Understand & Improve Memory Using Science-Based Tools

00:00:00.000 | - Welcome to the Huberman Lab Podcast,

00:00:02.260 | where we discuss science and science-based tools

00:00:04.900 | for everyday life.

00:00:05.900 | I'm Andrew Huberman,

00:00:10.200 | and I'm a professor of neurobiology and ophthalmology

00:00:13.060 | at Stanford School of Medicine.

00:00:14.880 | Today, we are discussing memory,

00:00:16.660 | in particular, how to improve your memory.

00:00:19.340 | Now, the study of memory is one

00:00:20.660 | that dates back many decades.

00:00:22.700 | And by now, there's a pretty good understanding

00:00:25.360 | of how memories are formed in the brain,

00:00:27.860 | the different structures involved

00:00:29.300 | and some of the neurochemicals involved.

00:00:31.220 | We will talk about some of that today.

00:00:33.620 | Often overlooked, however,

00:00:34.820 | is that memories are not just about learning.

00:00:37.580 | Memories are also about placing your entire life

00:00:40.160 | into a context.

00:00:41.580 | And that's because what's really special about the brain,

00:00:44.180 | and in particular, the human brain,

00:00:46.040 | is its ability to place events in the context

00:00:48.500 | of past events, the present, and future events,

00:00:52.660 | and sometimes even combinations of the past and present,

00:00:54.980 | or present and future, and so on.

00:00:57.460 | So when we talk about memory,

00:00:58.820 | what we're really talking about

00:01:00.300 | is how your immediate experiences relate

00:01:03.020 | to previous and future experiences.

00:01:06.220 | Today, I'm going to make clear how that process occurs.

00:01:09.320 | Even if you don't have a background in biology or psychology,

00:01:11.820 | I promise to put it into language

00:01:13.140 | that anyone can access and understand.

00:01:15.300 | And we are going to talk about the science

00:01:17.620 | that points to specific tools

00:01:19.700 | for enhancing learning and memory.

00:01:22.400 | We're also going to talk about unlearning and forgetting.

00:01:25.100 | There are, of course, instances

00:01:26.260 | in which we would like to forget things.

00:01:28.380 | And that too is a biological process

00:01:30.660 | for which great tools exist to, for instance,

00:01:34.540 | eliminate or at least reduce the emotional load

00:01:37.320 | of our previous experience that you really did not like,

00:01:39.980 | or that perhaps even was traumatic to you.

00:01:43.000 | So today, you're going to learn about the systems

00:01:46.100 | in the brain and body that establish memories.

00:01:49.320 | You're going to learn why certain memories

00:01:51.340 | are easier to form than others.

00:01:53.300 | And I'm going to talk about specific tools

00:01:55.640 | that are grounded in not just one,

00:01:57.900 | not just a dozen, but well over a hundred studies

00:02:00.860 | in animals and humans that point to specific protocols

00:02:04.620 | that you can use in order to stamp down

00:02:07.380 | learning of particular things more easily.

00:02:09.980 | And you can also leverage that same knowledge

00:02:12.620 | to better forget or unload the emotional weight

00:02:15.260 | of experiences that you did not like.

00:02:17.540 | We are also going to discuss topics

00:02:19.060 | like deja vu and photographic memory.

00:02:21.980 | And for those of you that do not have a photographic memory,

00:02:24.980 | and I should point out

00:02:25.820 | that I do not have a photographic memory either.

00:02:28.480 | Well, you will learn how to use your visual system

00:02:31.360 | in order to better learn visual and auditory information.

00:02:35.220 | There are protocols to do this

00:02:36.560 | grounded in excellent peer-reviewed research.

00:02:39.100 | So while you may not have a true photographic memory,

00:02:41.940 | by the end of the episode, you will have tools in hand,

00:02:44.140 | or I should say tools in mind or in eyes and mind

00:02:47.760 | to be able to encode and remember specific events

00:02:51.340 | better than you would otherwise.

00:02:53.340 | Before we begin, I'd like to emphasize

00:02:54.880 | that this podcast is separate

00:02:56.220 | from my teaching and research roles at Stanford.

00:02:58.380 | It is, however, part of my desire and effort

00:03:00.240 | to bring zero cost to consumer information

00:03:02.060 | about science and science-related tools

00:03:04.060 | to the general public.

00:03:05.460 | In keeping with that theme,

00:03:06.520 | I'd like to thank the sponsors of today's podcast.

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00:07:54.780 | Okay, let's talk about memory

00:07:56.340 | and let's talk about how to get better

00:07:57.840 | at remembering things.

00:07:59.420 | In order to address both of those things,

00:08:01.220 | we need to do a little bit of brain science 101 review,

00:08:04.460 | and I promise this will only take two minutes,

00:08:06.580 | and I promise that even if you don't have a background

00:08:08.860 | in biology, it will make sense.

00:08:10.640 | We are constantly being bombarded with physical stimuli,

00:08:14.780 | patterns of touch on our skin,

00:08:17.420 | light to our eyes, light to our skin for that matter,

00:08:21.100 | smells, tastes, and sound waves.

00:08:23.820 | In fact, if you can hear me saying this right now,

00:08:25.620 | well, that's the consequence of sound waves

00:08:28.020 | arriving into your ears through headphones, a computer,

00:08:30.660 | or some other speaker device.

00:08:32.660 | Each one of and all of those sensory stimuli

00:08:35.560 | are converted into electricity and chemical signals

00:08:39.120 | by your so-called nervous system,

00:08:40.400 | your brain, your spinal cord,

00:08:41.580 | and all their connections with the organs of the body

00:08:43.860 | and all the connections of your organs of the body

00:08:46.560 | back to your brain and spinal cord.

00:08:48.460 | One of the primary jobs of your nervous system, in fact,

00:08:50.620 | is to convert physical events in the world

00:08:53.020 | that are non-negotiable, right?

00:08:54.920 | Photons of light are photons of light.

00:08:56.680 | Sound waves are sound waves.

00:08:57.820 | There's no changing that,

00:08:59.140 | but your nervous system does change that.

00:09:01.140 | It converts those things into electrical signals

00:09:04.280 | and chemical signals,

00:09:05.720 | which are the language of your nervous system.

00:09:08.180 | Now, just because you're being bombarded

00:09:09.620 | with all this sensory information

00:09:10.880 | and it's being converted into a language

00:09:12.840 | that neurons and the rest of your nervous system

00:09:14.820 | can understand does not mean that you are aware of it all.

00:09:18.360 | In fact, you are only going to perceive a small amount

00:09:22.020 | of that sensory information.

00:09:23.760 | For instance, if you can hear me speaking right now,

00:09:26.400 | you are perceiving my voice,

00:09:28.420 | but you are also most likely neglecting the feeling

00:09:31.620 | of the contact of your skin

00:09:32.680 | with whichever surface you happen to be sitting

00:09:34.980 | or standing on.

00:09:36.740 | So it is only by perceiving a subset,

00:09:39.740 | a small fraction of the sensory events in our environment

00:09:42.820 | that we can make sense of the world around us.

00:09:44.400 | Otherwise we would just be overwhelmed

00:09:46.280 | with all the things that are happening

00:09:47.620 | in any one given moment.

00:09:49.480 | Now, memory is simply a bias in which perceptions

00:09:54.480 | will be replayed again in the future.

00:09:57.200 | Anytime you experience something,

00:09:58.980 | that is the consequence of specific chains of neurons

00:10:01.560 | that we call neural circuits being activated.

00:10:04.320 | And memory is simply a bias in the likelihood

00:10:07.540 | that that specific chain of neurons

00:10:09.580 | will be activated again.

00:10:12.080 | So for instance, if you can remember your name,

00:10:14.420 | and I certainly hope that you can,

00:10:16.440 | well, that means that there are specific chains of neurons

00:10:19.620 | in your brain that represent your name.

00:10:22.140 | And when those neurons connect with one another

00:10:25.220 | and communicate electrically with one another

00:10:27.380 | in a particular sequence, you remember your name.

00:10:30.660 | Were that particular chain of neurons to be disrupted,

00:10:34.220 | you would not be able to remember your name.

00:10:36.400 | Now, this might seem immensely simple,

00:10:37.960 | but it raises this really interesting question,

00:10:40.820 | which we talked about before,

00:10:42.960 | which is why do we remember certain things and not others?

00:10:45.720 | Because according to what I've just said,

00:10:49.040 | as you go through life,

00:10:50.140 | you're experiencing things all the time.

00:10:51.860 | You're constantly being bombarded with sensory stimuli.

00:10:54.860 | Some of those sensory stimuli you perceive,

00:10:56.880 | and only some of those perceptions

00:10:59.260 | get stamped down as memories.

00:11:02.020 | Today, I'm going to teach you how certain things

00:11:04.480 | get stamped down as memories.

00:11:05.880 | And I'm going to teach you how to leverage that process

00:11:08.800 | in order to remember the information that you want

00:11:11.160 | far better.

00:11:12.300 | Now, even though I've told you that a memory

00:11:13.840 | is simply a bias in the likelihood

00:11:15.340 | that a particular chain of neurons will be activated

00:11:17.560 | in a particular sequence again and again,

00:11:20.980 | it doesn't operate on its own.

00:11:23.260 | In fact, most of what we remember

00:11:25.620 | takes place in a context of other events.

00:11:29.200 | So for instance, you can most likely remember your name,

00:11:32.780 | and yet you're probably not thinking about

00:11:35.500 | when it was that you first learned your name.

00:11:38.040 | This generally happens

00:11:39.420 | when we are very, very young children.

00:11:41.580 | And yet I'm guessing you could probably remember

00:11:45.220 | a time when someone mispronounced your name

00:11:47.580 | or made fun of your name.

00:11:49.260 | Or as the case was for me,

00:11:51.140 | I got to the third grade and there were two Andrews.

00:11:53.860 | And sadly for me, I lost the coin flip

00:11:56.900 | that allowed me to keep Andrew.

00:11:58.140 | And from about third grade until about 12th grade,

00:12:02.460 | people called me Andy, which I really did not prefer.

00:12:04.980 | So if you call me Andy in the comments,

00:12:07.060 | I'll delete your comment.

00:12:07.900 | Just kidding, doesn't bother me that much.

00:12:09.980 | But eventually I reclaimed Andrew as my name.

00:12:13.440 | Well, it was mine to begin with and throughout,

00:12:15.460 | but I started going by Andrew again.

00:12:18.280 | Why do I say this?

00:12:19.120 | Well, there's a whole context to my name for me.

00:12:22.140 | And there may or may not be a whole context

00:12:24.520 | to your name for you.

00:12:25.620 | But presumably if you asked your parents

00:12:27.000 | why they named you your given name,

00:12:28.960 | you'll get a context, et cetera.

00:12:30.940 | That context reflects the activation

00:12:33.800 | of other neural circuits that are also related

00:12:35.980 | to other events in your life, not just your name,

00:12:38.500 | but probably your siblings names and who your parents are

00:12:41.580 | and on and on and on.

00:12:43.020 | And so the way memory works is that each individual thing

00:12:47.200 | that we remember or that we want to remember

00:12:48.980 | is linked to something by either a close,

00:12:51.700 | a medium or a very distant association.

00:12:54.540 | This turns out to be immensely important.

00:12:56.900 | I know many of you will read or will encounter programs

00:13:01.080 | that are designed to help you enhance your memory.

00:13:03.340 | You have these phenoms that can remember 50 names

00:13:06.500 | in a room full of people,

00:13:08.060 | or they can remember a bunch of names of novel objects

00:13:11.060 | or maybe even in different languages.

00:13:12.820 | And oftentimes that's done by association.

00:13:15.520 | So people will come up with little mental tricks

00:13:18.020 | to either link the sound of a word

00:13:21.260 | or the meaning of a word in some way that's meaningful

00:13:23.520 | for them and will enhance their memory.

00:13:25.520 | That can be done and is impressive when we see it.

00:13:28.080 | And for those of you who can do that, congratulations.

00:13:30.340 | Most of us can't do that,

00:13:32.060 | or at least it requires a lot of effort and training.

00:13:35.220 | However, there are things that we can do

00:13:37.520 | that leverage the natural biology of our nervous system

00:13:40.700 | to enhance learning and memory of particular perceptions

00:13:43.700 | and particular information.

00:13:45.900 | Let's first just talk about the most basic ways

00:13:48.420 | that we learn and remember things

00:13:49.860 | and how to improve learning and memory.

00:13:52.180 | And the most basic one is repetition.

00:13:55.140 | Now the study of memory and the role of repetition

00:13:58.100 | actually dates back to the late 1800s, early 1900s,

00:14:01.660 | when Ebbinghaus developed the first

00:14:03.780 | so-called learning curves.

00:14:06.020 | Now learning curves are simply what results

00:14:08.840 | when you quantify how many repetitions of something

00:14:11.480 | are required in order to remember something.

00:14:15.100 | In fact, it's been said that Ebbinghaus liberated

00:14:17.960 | the understanding of learning from the philosophers

00:14:20.560 | by generating these learning curves.

00:14:22.480 | What do you mean by that?

00:14:23.320 | Well, before Ebbinghaus came along,

00:14:26.960 | learning and memory were thought to be philosophical ideas.

00:14:31.420 | Ebbinghaus came along and said,

00:14:33.480 | well, let's actually take some measurements.

00:14:35.980 | Let's measure how well I can remember a sequence of words

00:14:39.200 | or a sequence of numbers if I just repeat them.

00:14:41.660 | So what Ebbinghaus did is he would take a sequence

00:14:43.780 | of numbers or words on a page and he would read them.

00:14:47.700 | And then he would take a separate sheet of paper

00:14:50.740 | and we have to presume he didn't cheat.

00:14:52.720 | And he would write down as many of them as he could

00:14:55.140 | and he would try and keep them in the same sequence.

00:14:57.140 | Then he would compare to the original list

00:14:58.980 | and he would see how many errors he made.

00:15:00.780 | And you do this over and over and over again.

00:15:03.340 | And as you would expect,

00:15:04.740 | early in the training and the learning,

00:15:08.620 | it took a lot more repetitions to get the sequence correct.

00:15:11.340 | And over time, it took fewer sequences.

00:15:13.900 | And he referred to that difference

00:15:15.580 | in the initial number of repetitions that he had to perform

00:15:19.300 | versus the later number of repetitions

00:15:22.340 | that he had to perform as a so-called savings.

00:15:25.140 | So he literally thought of the brain

00:15:26.940 | as having to generate a kind of a currency of effort.

00:15:30.660 | And he talked about savings as the reduction

00:15:34.000 | in the amount of effort that he had to put forward

00:15:36.340 | in order to learn information.

00:15:37.740 | And what he got was a learning curve.

00:15:38.900 | And you can imagine what that learning curve looked like.

00:15:40.640 | It was at a very sharp peak at the beginning

00:15:42.580 | that dropped off over time.

00:15:44.180 | And of course he remembered

00:15:45.260 | all this meaningless information.

00:15:47.240 | But even though the information

00:15:48.660 | might've been meaningless, the experiment itself

00:15:51.660 | and what Ebbinghaus demonstrated was immensely meaningful

00:15:54.860 | because what it said was that with repetition,

00:15:57.760 | we can activate particular sequences of neurons.

00:16:01.600 | And that repeated activation lays down

00:16:04.600 | what we call a memory.

00:16:06.080 | And that might all seem like a big duh,

00:16:07.820 | but prior to Ebbinghaus, none of that was known.

00:16:09.960 | Now I should also say Ebbinghaus,

00:16:12.140 | because of when he was alive,

00:16:13.540 | was not aware of these things that we call neural circuits.

00:16:16.200 | It was in 1906 that Golgi and Cajal got the Nobel prize

00:16:20.360 | for actually showing that neurons are independent cells

00:16:22.800 | connected by synapses,

00:16:23.920 | these little gaps between them where they communicate.

00:16:26.220 | So he may have been aware of that,

00:16:27.780 | but the whole notion of neural circuits

00:16:29.140 | hadn't really come about.

00:16:30.440 | Nevertheless, what the Ebbinghaus learning curves

00:16:32.760 | really established was that sheer repetition,

00:16:36.340 | just repeating things over and over and over again

00:16:39.220 | is sufficient to learn.

00:16:41.500 | Something that no doubt had been observed before,

00:16:43.560 | but it had never been formally quantified.

00:16:46.860 | Now, if we look at that result,

00:16:50.260 | there's something really important

00:16:51.420 | that lies a little bit cryptic.

00:16:53.140 | That's not so obvious to most people,

00:16:55.540 | which is the information that he was trying to learn

00:16:58.900 | wasn't any more interesting the second time

00:17:01.440 | than it was the first,

00:17:02.780 | probably was even less interesting

00:17:04.700 | and less and less interesting with each repetition.

00:17:06.820 | And yet it was sheer repetition

00:17:09.140 | that allowed him to remember.

00:17:11.900 | Now, sometime later in the early to mid 1920s,

00:17:15.020 | a psychologist in Canada named Donald Hebb

00:17:17.500 | came up with what was called Hebb's postulate.

00:17:20.060 | And Hebb's postulate, broadly speaking,

00:17:23.060 | is this idea that if a sequence of neurons is active

00:17:28.060 | at the same time or at roughly the same time,

00:17:31.500 | that that would lead to a strengthening of the connections

00:17:33.880 | between those neurons.

00:17:35.380 | And many, many decades of experimentation later,

00:17:38.460 | we now know that postulate to be true.

00:17:41.020 | Neurons themselves are not smart.

00:17:44.780 | They don't have knowledge.

00:17:46.420 | So every memory is the consequences, I told you before,

00:17:49.660 | of the repeated activation of a particular chain of neurons.

00:17:53.300 | And what Ebbinghaus showed through repetition

00:17:55.640 | and what Donald Hebb proposed,

00:17:57.980 | and it was eventually verified through experimentation

00:18:00.620 | on animals and humans,

00:18:02.340 | was that if you encourage the co-activation of neurons,

00:18:06.480 | meaning have neurons fire at roughly the same time,

00:18:11.220 | they will strengthen their connections.

00:18:12.960 | It leads to a bias in the probability

00:18:14.940 | that those neurons will be active again.

00:18:17.160 | Now, this is vitally important

00:18:18.500 | because nowadays we hear a lot about how memories

00:18:21.820 | are the consequence of new neurons added in the brain,

00:18:25.460 | or that every time you learn something,

00:18:28.340 | a new connection in your brain forms.

00:18:30.780 | Well, sorry to break it to you,

00:18:31.820 | but that's simply not the case.

00:18:34.100 | Most of the time, and I want to emphasize most, not all,

00:18:36.800 | but most of the time when we learn something,

00:18:38.940 | it's because existing neurons, not new neurons,

00:18:42.400 | but existing neurons strengthen their connection

00:18:45.460 | through co-activation over and over and over

00:18:48.940 | through repetition, or, and this is a very important or,

00:18:53.060 | or through very strong activation once and only once.

00:18:58.060 | In fact, there's something called one trial learning

00:18:59.900 | whereby we experience something

00:19:01.980 | and we will remember that thing forever.

00:19:05.300 | This is often most associated with negative events,

00:19:08.100 | and I'll explain why in a few minutes,

00:19:10.000 | but it can also be associated with positive events,

00:19:12.940 | like the first time you saw your romantic partner

00:19:16.960 | or something that happened with that romantic partner,

00:19:19.660 | or the first time that you saw your child,

00:19:22.380 | or any other positive event,

00:19:23.920 | as well as any other extremely negative event.

00:19:26.820 | So again, both repetition,

00:19:28.740 | and I guess we could label it intensity,

00:19:31.900 | but what we really mean when we say intensity

00:19:33.620 | is strong activation of neurons can lay down these traces,

00:19:37.240 | these circuits that are far more likely to be active again,

00:19:41.620 | than had there not been repetition

00:19:43.820 | or not some strong activation of those circuits.

00:19:47.220 | So with that in mind,

00:19:48.320 | let's return to the original contrarian question

00:19:51.860 | that I raised before,

00:19:52.720 | which is why do we remember anything?

00:19:55.760 | Every day you wake up,

00:19:57.380 | your neurons in your brain and body are active,

00:20:00.140 | different neural circuits are active,

00:20:01.780 | and yet you only remember a small fraction

00:20:04.140 | of the things that happen each day,

00:20:05.540 | and yet you retain a lot of information from previous days

00:20:08.060 | and the days before those and so on.

00:20:10.580 | It is only with a lot of repetition

00:20:14.260 | or with extremely strong activation

00:20:17.100 | of a given neural circuit that we will create new memories.

00:20:20.060 | And so in a few minutes,

00:20:20.900 | I'll explain how to get extremely strong activation

00:20:24.000 | of particular neural circuits.

00:20:25.980 | Repetition is pretty obvious, repetition is repetition,

00:20:29.080 | but in a few minutes,

00:20:30.620 | I'll illustrate a whole set of experiments

00:20:32.980 | and a whole set of tools

00:20:34.340 | that point to how you can get extra strong activation

00:20:38.140 | of a given neural circuit as it relates to learning

00:20:40.620 | so that you will remember that information,

00:20:43.180 | perhaps not just with one trial of learning,

00:20:45.840 | but certainly with far fewer repetitions

00:20:48.500 | than would be required otherwise.

00:20:50.380 | Before we go any further,

00:20:51.500 | I want to preface the discussion by saying

00:20:53.020 | that there are a lot of different kinds of memory.

00:20:55.020 | In fact, were you to take a voyage

00:20:56.700 | into the neuroscience and or psychology of memory,

00:21:00.180 | you would find an immense number of different terms

00:21:02.460 | to describe the immense number of different types of memory

00:21:05.760 | that researchers focus on.

00:21:07.880 | But for sake of today's discussion,

00:21:09.680 | really just want to focus on short-term memory,

00:21:11.760 | medium-term memory and long-term memory.

00:21:14.400 | And while there's still debate,

00:21:16.320 | as is always the case with scientists, frankly,

00:21:18.500 | about the exact divisions between short-term,

00:21:20.380 | medium and long-term memory,

00:21:22.120 | we can broadly define short-term memory and long-term memory

00:21:26.740 | and we can describe a couple of different types of those

00:21:29.220 | that I think you can relate to in your everyday life.

00:21:32.020 | The most common form of short-term memory

00:21:33.660 | that we're going to focus on is called working memory.

00:21:36.180 | Working memory is your ability to keep a chain of numbers

00:21:39.720 | in mind for some period of time,

00:21:41.880 | but the expectation really isn't

00:21:44.180 | that you would remember those numbers the next day

00:21:46.780 | and certainly not the next week.

00:21:48.220 | So a good example would be a phone number.

00:21:49.780 | If I were to tell you a phone number, 4932938,

00:21:53.480 | well, you could probably remember it 4932938,

00:21:56.980 | but if I came back tomorrow and asked you

00:21:59.420 | to repeat that chain of numbers, most likely you would not,

00:22:02.420 | unless of course we used a particular tool

00:22:05.180 | to stamp down that memory into your mind

00:22:07.180 | and commit it to long-term memory.

00:22:10.040 | Now, of course, in this day and age,

00:22:11.580 | most people have phone numbers programmed into their phone.

00:22:14.820 | They don't really have to remember the exact numbers.

00:22:16.620 | It's usually done by contact identity and so forth.

00:22:20.900 | So a different example

00:22:21.960 | that some of you are probably more familiar with

00:22:24.060 | would be those security codes.

00:22:25.900 | So you try and log on to an app or a website

00:22:28.180 | and it asks you for a security code

00:22:29.860 | that's been sent to your text messages

00:22:31.580 | and then you can either plug that in directly in some cases

00:22:33.940 | or you have to remember that short sequence

00:22:35.340 | of anywhere usually from six to seven,

00:22:37.580 | sometimes eight numbers.

00:22:38.780 | Your ability to do that, to switch back and forth

00:22:40.860 | between web pages or apps and plug in that number

00:22:45.560 | by remembering the sequence and plugging it in

00:22:47.780 | by texting or keying it in on your keyboard,

00:22:50.800 | that's a really good example of working memory.

00:22:53.100 | Long-term memory of the sort

00:22:54.380 | that we're going to be talking a lot about today

00:22:56.420 | is your ability to commit certain patterns of information,

00:22:59.320 | either cognitive information or motor information, right?

00:23:02.620 | The ability to move your limbs in a particular sequence

00:23:05.560 | over long periods of time,

00:23:07.380 | such that you could remember it a day or a week or a month

00:23:10.260 | or maybe even a year or several years later.

00:23:12.900 | So we've got short-term memory and long-term memory

00:23:14.600 | and we've got this working memory,

00:23:15.900 | which is kind of keeping something online,

00:23:18.140 | but then discarding it, okay?

00:23:19.980 | Not online on a computer, but online within your brain.

00:23:22.780 | There are also two major categories of memory

00:23:25.380 | that I'd like you to know about.

00:23:26.540 | One is explicit memory.

00:23:28.460 | So this is not necessarily explicit of the sort

00:23:31.140 | that you're used to thinking about,

00:23:32.960 | but rather the fact that you can declare you know something.

00:23:36.420 | So you have an explicit memory of your name.

00:23:39.500 | Presumably you have an explicit memory of the house

00:23:42.380 | or the apartment that you grew up in.

00:23:44.340 | You know something and you know you know it

00:23:46.700 | and you can declare it.

00:23:47.700 | So I can ask you,

00:23:48.620 | what was the color of the first car that you owned?

00:23:51.780 | Or what is the color of your romantic partner's hair?

00:23:56.660 | These sorts of things.

00:23:57.480 | That's an explicit declarative memory,

00:23:59.740 | but you also have explicit procedural memories.

00:24:04.100 | Now, procedural memories, as the name suggests,

00:24:06.300 | involve action sequences.

00:24:08.980 | The simplest one, it's almost ridiculously simple,

00:24:11.620 | is walking.

00:24:12.460 | If I say, how is it that you walk from one room

00:24:15.300 | to the other, you'd probably say,

00:24:16.460 | well, I go that direction, then I turn left.

00:24:17.960 | I say, no, no, no, no.

00:24:18.820 | How is it exactly that you do it?

00:24:20.700 | And say, well, I move my left foot,

00:24:22.220 | then my right foot, then my left foot.

00:24:24.100 | And you could describe that.

00:24:25.860 | So it's an explicit procedural memory.

00:24:27.940 | So much so that if you were going to teach a young toddler

00:24:30.660 | how to walk, you would probably say,

00:24:32.660 | okay, good, good, try.

00:24:33.840 | Okay, and you, you know,

00:24:34.940 | probably that's going to be pre-language for the toddler,

00:24:37.620 | but you're going to encourage them to move one leg

00:24:40.040 | than the other.

00:24:40.880 | And you're going to encourage and reward them

00:24:43.100 | for moving one leg than the other

00:24:44.700 | because you have an explicit procedural memory

00:24:47.420 | of how to walk.

00:24:48.980 | Okay, almost ridiculously simple,

00:24:50.580 | maybe even truly ridiculously simple.

00:24:52.660 | But nonetheless, when you think about it in the context

00:24:55.340 | of neural circuits and neural firing, pretty amazing.

00:24:58.220 | Even more amazing is the fact that all explicit memories,

00:25:03.220 | both declarative and procedural explicit memories

00:25:07.860 | can be moved from explicit to implicit.

00:25:11.980 | What do I mean by that?

00:25:12.980 | Well, in the example of walking,

00:25:15.520 | you might've chuckled a little bit

00:25:16.600 | or kind of shook your head and said,

00:25:18.180 | that's a ridiculous thing to ask.

00:25:19.740 | How do I walk from one room to the next?

00:25:21.180 | I just walk, I just do it.

00:25:22.900 | Ah, well, what is just do it?

00:25:24.980 | What it is is that you have an implicit understanding,

00:25:28.380 | meaning your nervous system knows how to walk

00:25:31.660 | without you actually having to think about

00:25:35.460 | what you know about how to walk.

00:25:37.100 | You just get up out of your chair

00:25:38.380 | or you get up out of bed and you walk.

00:25:40.460 | In the brain, you have a structure.

00:25:43.260 | In fact, you have one on each side of your brain.

00:25:45.980 | It's called the hippocampus.

00:25:47.460 | The hippocampus literally means seahorse.

00:25:49.900 | Anatomists like to name brain structures after things

00:25:52.780 | that they think those brain structures resemble.

00:25:55.480 | When I look at the hippocampus,

00:25:57.100 | frankly, it doesn't look like a seahorse,

00:25:58.960 | which either reflects my lack of understanding

00:26:01.440 | of what a seahorse really looks like, a visual deficit,

00:26:03.780 | or I think it's fair to say that those anatomists

00:26:06.240 | were using a little bit of creative elaboration

00:26:09.780 | when thinking about what the hippocampus looks like.

00:26:12.220 | Nonetheless, it is a curved structure.

00:26:15.360 | It has many layers.

00:26:17.200 | It's been described by my colleague, Robert Sapolsky,

00:26:19.700 | and by others as looking more like a jelly roll

00:26:22.620 | or a cinnamon roll is what it looks like to me.

00:26:25.740 | And if you were to take one cinnamon roll,

00:26:28.020 | chop it down the middle.

00:26:29.700 | So now you've got two half cinnamon rolls

00:26:32.020 | and rather than put them back together

00:26:33.920 | in the configuration they were before,

00:26:35.520 | you just slide one down so that you've got essentially

00:26:39.100 | two C's, two C-shaped halves of the cinnamon roll

00:26:43.380 | and you push them together,

00:26:45.420 | slightly offset from one another.

00:26:47.180 | Well, that's what the hippocampus looks like to me.

00:26:49.340 | And I think that's a far better description

00:26:51.540 | of its actual physical structure.

00:26:53.300 | But I guess if you were to use that physical structure

00:26:56.560 | as the name, well, then you'd have to open up

00:26:57.780 | a brain atlas and it would be called

00:26:59.700 | two half C cinnamon rolls stuffed halfway together.

00:27:02.100 | So that's not very good.

00:27:02.940 | So I guess seahorse will work.

00:27:04.620 | Hippocampus is the name of this structure

00:27:07.140 | and it is the site in your brain.

00:27:10.180 | And again, you have one on each side of your brain

00:27:13.140 | in which explicit declarative memories are formed.

00:27:17.460 | It is not where those memories are stored and maintained.

00:27:21.220 | It is where they are established in the first place.

00:27:23.980 | In contrast, implicit memories, right?

00:27:28.120 | These subconscious memories are formed and stored

00:27:32.540 | elsewhere in the brain, mainly by areas like the cerebellum,

00:27:36.180 | but also the neocortex,

00:27:37.300 | the kind of outer shell of your brain.

00:27:39.180 | The cerebellum is, it literally means mini brain.

00:27:42.180 | And it does in fact look like a mini brain

00:27:44.300 | and is in the back of the brain.

00:27:45.660 | And the neocortex is the outer part of the brain

00:27:47.920 | that covers all the other stuff.

00:27:49.900 | So the hippocampus is vitally important

00:27:53.420 | for establishing these new declarative memories

00:27:56.180 | of what you know and what you know how to do.

00:28:00.260 | Now, in order to really understand

00:28:02.060 | the role of the hippocampus in memory,

00:28:03.660 | in particular explicit declarative

00:28:06.220 | and explicit procedural memory,

00:28:08.020 | and to really understand how that's distinct

00:28:10.340 | from implicit declarative and implicit procedural memories,

00:28:15.340 | we have to look to a clinical case.

00:28:17.820 | And the clinical case that I'm referring to

00:28:19.300 | is a patient who went by the name HM.

00:28:22.140 | Patients go by their initials

00:28:23.800 | in order to maintain confidentiality of their real identity.

00:28:27.500 | HM had what's called intractable epilepsy.

00:28:31.500 | So he would have these really dramatic

00:28:33.780 | so-called grand mal seizures or drop seizures.

00:28:37.120 | For those of you that know somebody with epilepsy

00:28:39.540 | or that have epilepsy, you might be familiar with this.

00:28:43.680 | You can have petit mal seizures, which are minor seizures.

00:28:47.100 | You can have tonic-clonic seizures,

00:28:48.540 | which are sometimes not even detectable.

00:28:50.320 | You can have absent seizures where people will just stop.

00:28:52.820 | It's almost as if their brain goes on pause

00:28:55.020 | and they'll just stop there.

00:28:55.860 | It was reported actually that Einstein had absent seizures,

00:28:59.120 | although I don't know that

00:28:59.960 | that's ever really been confirmed neurologically.

00:29:02.900 | Grand mal seizures are extremely severe,

00:29:06.800 | and that's what HM had.

00:29:08.180 | So he could just be going about his day

00:29:10.140 | and maybe even cooking or doing something,

00:29:12.500 | driving, operating any kind of machinery,

00:29:14.740 | and then all of a sudden he would just have a drop seizure

00:29:17.500 | so he would just physically drop

00:29:18.940 | and go into a grand mal seizure.

00:29:20.360 | So convulsing of the whole body,

00:29:22.180 | loss of consciousness, et cetera.

00:29:24.280 | Or he would feel it coming on.

00:29:26.320 | Oftentimes people with epilepsy

00:29:27.660 | can feel the epilepsy seizure coming on

00:29:29.700 | kind of like a wave from the back of the brain.

00:29:32.260 | And sometimes they can get to a safe circumstance,

00:29:34.340 | but not always.

00:29:35.180 | And so the frequency and the intensity of his seizures

00:29:38.240 | were so robust that the neurosurgeons and neurologists

00:29:41.840 | decided that they needed to locate the origin,

00:29:44.380 | what they call the foci of those seizures

00:29:47.580 | and remove that brain tissue.

00:29:49.460 | Because the way seizures work is they spread out

00:29:52.040 | from that focus or that foci of brain tissue.

00:29:56.500 | And unfortunately for HM,

00:29:58.980 | the focus of his seizures was the hippocampus.

00:30:02.220 | So after a lot of deliberation, a neurosurgeon,

00:30:05.480 | in fact, one of the most famous neurosurgeons

00:30:07.580 | in the world at that time

00:30:08.920 | made what are called electrolytic lesions,

00:30:11.860 | actually burned out the hippocampus in the brain of HM.

00:30:16.180 | And as a consequence, he lost all explicit memory.

00:30:20.840 | Now, the consequence of this was that he couldn't exist

00:30:23.480 | in normal, everyday life, like most people.

00:30:26.080 | So he had to live mostly, not entirely,

00:30:28.840 | but mostly in a kind of hospital setting.

00:30:31.940 | And I've talked to several people who have,

00:30:34.980 | I should say, who met HM directly

00:30:37.900 | because he's no longer alive,

00:30:39.940 | but an interaction with him might look like the following.

00:30:44.140 | He would walk up to you just fine.

00:30:45.880 | You wouldn't know that he had any kind of brain damage.

00:30:49.220 | He could walk fine.

00:30:50.420 | He could speak fine.

00:30:51.420 | And he'd say, "Hi, I'm Andrew."

00:30:53.340 | And he'd say, "Hi, I'm," whatever his name happened to be.

00:30:55.940 | He wouldn't say HM, but he'd probably say his real name.

00:30:58.720 | And then perhaps someone new would walk into the room.

00:31:02.200 | He might turn around, look at that person,

00:31:03.860 | as any of us might do, then turn around back to me

00:31:08.140 | and say, "Hi, what's your name?"

00:31:10.360 | And if I were to say, "Well, I just told you my name

00:31:12.500 | and you just told me your name.

00:31:14.140 | Do you remember that?"

00:31:14.980 | He'd say, "I'm sorry, I don't remember any of that.

00:31:16.780 | What's your name?"

00:31:17.620 | So you had to go through this over and over again.

00:31:19.200 | So a complete lack of explicit declarative memory.

00:31:22.820 | Now he did have some memory for previous events in his life

00:31:27.820 | that dated way back, okay?

00:31:30.180 | Again, hinting at the idea that memories

00:31:33.360 | are not necessarily stored in the hippocampus.

00:31:36.420 | They're just formed in the hippocampus.

00:31:37.900 | So once they've moved out of the hippocampus

00:31:39.460 | to other brain areas, he could still keep those memories.

00:31:42.260 | They're in a different database, if you will.

00:31:43.960 | They're in a different pattern of firing

00:31:45.420 | of other neural circuits, but he couldn't form new memories.

00:31:48.280 | Now there's some very important and interesting twists

00:31:51.220 | on what HM could and could not do

00:31:53.420 | in terms of learning and memory

00:31:55.180 | that teach us a lot about the brain.

00:31:56.800 | In fact, I think most neuroscientists would agree

00:31:59.100 | that this unfortunate case of HM's epilepsy

00:32:02.140 | and the subsequent neurosurgery that he had

00:32:04.600 | taught us much of what we know, or at least think about,

00:32:07.300 | in terms of human learning and memory.

00:32:09.660 | For instance, as I mentioned before,

00:32:11.580 | he still had implicit knowledge.

00:32:13.920 | He knew how to walk.

00:32:14.800 | He knew how to do certain things like make a cup of coffee.

00:32:17.820 | He knew the names of people that he had met

00:32:21.380 | much earlier in his life and so on.

00:32:23.900 | And yet he couldn't form new memories.

00:32:26.060 | Now in violation to that last statement,

00:32:29.380 | there were some elements of HM's emotionality

00:32:32.920 | that suggests that there was some sort of residual capacity

00:32:36.500 | to learn new information,

00:32:38.060 | but it wasn't what we normally think of

00:32:40.500 | as explicit declarative or procedural memory.

00:32:43.080 | For instance, it's been reported, or it's been said,

00:32:46.980 | I should say, because I don't know that the studies

00:32:49.000 | were ever done with intense physiological measurements,

00:32:51.860 | that if you were to tell HM a joke

00:32:54.820 | and he thought it was funny, he would laugh really hard.

00:32:58.180 | Though he liked jokes, so you'd tell him, you'd say,

00:32:59.760 | "HM, I want to tell you a joke."

00:33:01.760 | You'd tell him a joke and he'd laugh really hard.

00:33:03.940 | Then you could leave the room, come back,

00:33:05.980 | and tell him the same joke again.

00:33:07.980 | Now, keep in mind, he did not remember

00:33:09.700 | that you told him the joke previously.

00:33:11.980 | And the second time he would laugh a little bit less.

00:33:14.580 | And then you'd leave the room, come back again,

00:33:17.220 | say, "Hi, I'm Andrew."

00:33:18.700 | And he'd say, "Oh, nice to meet you."

00:33:19.620 | Because as you recall, because you can recall things,

00:33:23.040 | but he couldn't recall things.

00:33:24.500 | He didn't know that he just met you,

00:33:25.820 | or at least he couldn't remember it.

00:33:27.240 | You tell him the joke a third time or a fourth time.

00:33:29.340 | And with each subsequent telling of the joke,

00:33:31.620 | he found it a little less funny, just as,

00:33:34.920 | keep this in mind, folks.

00:33:36.360 | If you tell a joke and you get a big laugh,

00:33:39.180 | don't tell it again, at least not immediately,

00:33:42.060 | not to the same person or the same crowd,

00:33:44.360 | because the second time it's a little less funny,

00:33:46.600 | and the third time it's a little less funny.

00:33:47.980 | And that actually has to do with a whole element of dopamine

00:33:51.180 | and its relationship to surprise.

00:33:53.360 | And that's the topic of a future podcast

00:33:55.260 | where we talk all about humor and novelty in the brain.

00:33:58.420 | But the point being that certain forms of memory

00:34:02.140 | seem to exist in a kind of phantom-like way

00:34:05.000 | within HM's brain.

00:34:06.400 | What do I mean by that?

00:34:07.300 | Well, this underscores the fact that he had

00:34:09.880 | an implicit memory of having heard the joke before.

00:34:13.620 | And it suggests that humor, or at least what we find funny,

00:34:16.720 | is somehow more related to procedures,

00:34:19.300 | similar to walking or motor ability,

00:34:21.540 | than it is to the precise content of that joke.

00:34:25.940 | That's a little bit of an abstract concept,

00:34:27.480 | but the point is that HM lacked explicit declarative memory.

00:34:31.320 | He couldn't tell you what he had just heard.

00:34:34.020 | He could not learn new information.

00:34:36.120 | And he couldn't tell you how to do something

00:34:38.600 | unless he had learned how to do that something

00:34:40.940 | many years prior.

00:34:42.880 | Now, there've been a lot of other patients besides HM

00:34:45.620 | that have had brain lesions due to epilepsy,

00:34:49.200 | or I should say, due to surgeries to treat epilepsy,

00:34:51.980 | due to strokes, due to sadly gunshot wounds

00:34:55.540 | and other forms of what we call infarct,

00:34:58.540 | infarct, I-N-F-A-R-C-T, infarct is the word we use

00:35:03.540 | to describe damage to a particular brain region.

00:35:07.180 | And many different patients with many different patterns

00:35:10.240 | of infarct have taught us a lot about how memory

00:35:13.960 | and other aspects of the brain work.

00:35:15.700 | HM really teaches us that what we know

00:35:21.280 | and what we are able to do is the consequence of things

00:35:24.740 | that we are aware of and learnings that have been passed off

00:35:28.200 | into subconscious knowledge, that our body knows,

00:35:31.000 | our brain knows, but we don't know exactly

00:35:33.920 | how we know that thing.

00:35:35.560 | And I tell you the story about HM's ability

00:35:37.980 | to understand a joke,

00:35:39.800 | but that with repeated telling of a joke,

00:35:42.340 | it has less and less and less of an impact

00:35:44.460 | in creating a sense of laughter, of humor in HM,

00:35:49.460 | not as just an anecdote to flesh out his story,

00:35:53.280 | but because emotion itself turns out to be the way

00:35:57.240 | in which we can enhance memories,

00:35:59.620 | even if those are memories for things that are not funny,

00:36:02.760 | are not intensely sad, are not immensely happy,

00:36:07.120 | or don't evoke a really strong emotional response

00:36:10.160 | or even any emotional response.

00:36:12.980 | And the reason for that is that emotions,

00:36:15.760 | just like perception, just like sensation,

00:36:18.620 | are the consequence of particular neurochemicals

00:36:21.080 | being present in our brain and body.

00:36:22.720 | And as I'm going to tell you next,

00:36:24.780 | there are particular neurochemicals

00:36:26.920 | that you can leverage in order

00:36:28.600 | to learn specific information faster

00:36:31.280 | and to remember it for a much longer period of time,

00:36:34.160 | maybe even forever.

00:36:35.520 | And you can do that by leveraging the relationship

00:36:37.880 | in your nervous system between your brain and your body

00:36:41.500 | and your body back to your brain.

00:36:44.240 | So let's talk about tools for enhancing memory.

00:36:46.840 | Now there's one tool that is absolutely clear works,

00:36:51.360 | and it's always worked, it works now,

00:36:53.860 | and it will work forever.

00:36:56.240 | And that's repetition.

00:36:57.480 | The more often that you perform something

00:37:00.480 | or that you recite something,

00:37:02.340 | the more likely you are to remember it in the future.

00:37:05.680 | And while that might seem obvious,

00:37:07.380 | it's worth thinking about what's happening

00:37:09.580 | when you repeat something.

00:37:11.000 | But when I say what's happening, I mean at the neural level.

00:37:13.840 | What's happening is that you're encouraging the firing

00:37:16.660 | of particular chains of neurons

00:37:18.880 | that reside in a particular circuit, right?

00:37:21.180 | So a particular sequence of neurons playing neuron A, B, C, D

00:37:24.960 | played in that particular sequence

00:37:26.120 | over and over and over again.

00:37:27.920 | And with more repetitions,

00:37:29.440 | you get more strengthening of those nerve connections.

00:37:33.300 | Now, repetition works, but the problem for most people

00:37:37.680 | is that they either don't have the patience,

00:37:40.020 | they don't have the time,

00:37:40.880 | and sometimes they literally don't have the time

00:37:42.400 | because they've got a deadline

00:37:44.120 | on something that they're trying to remember and learn,

00:37:47.220 | or they simply would like to be able

00:37:49.380 | to remember things better in general,

00:37:51.780 | remember them more quickly.

00:37:53.820 | This process of accelerating repetition-based learning

00:37:57.640 | so that your learning curve doesn't go

00:37:59.680 | from having to perform something 1,000 times

00:38:02.580 | and then gradually over time, it's 1,750 times a day,

00:38:06.320 | 500 times a day, 300 times a day,

00:38:08.560 | and down to no repetitions, right?

00:38:10.400 | You can just perform that thing

00:38:12.000 | the first time and every time.

00:38:13.800 | Well, there is a way to shift that curve

00:38:16.820 | so that you can essentially establish stronger connections

00:38:20.920 | between the neurons that are involved

00:38:22.840 | in generating that memory or behavior more quickly.

00:38:26.800 | How do you do that?

00:38:27.660 | Well, in order to answer that,

00:38:29.220 | we have to look at the beautiful work

00:38:31.760 | of James McGaugh and Larry Cahill.

00:38:34.680 | James McGaugh and Larry Cahill did a number of experiments

00:38:37.260 | over several decades, really,

00:38:39.240 | based on a lot of animal literature,

00:38:41.460 | but mainly focused on humans

00:38:44.140 | that really established what's required

00:38:46.960 | to get better at remembering things

00:38:49.600 | and to do so very quickly.

00:38:51.620 | I want to talk about one experiment that they did

00:38:53.860 | that was particularly important,

00:38:55.980 | and we will provide a link to this paper.

00:38:57.540 | It's some years old now, but the results still hold up.

00:39:00.700 | In fact, the results establish an entire field

00:39:03.420 | of memory in neuroscience and psychology.

00:39:06.000 | What they did is they had human subjects

00:39:08.900 | come into the laboratory and to read a short paragraph

00:39:12.060 | of about 12 sentences,

00:39:14.440 | and the key thing is that some subjects read a paragraph

00:39:18.620 | that was pretty mundane.

00:39:20.920 | The content, the information within the paragraph

00:39:23.460 | was all related to the content of the previous sentence,

00:39:26.340 | so it was a cogent paragraph, right?

00:39:27.980 | It just wasn't meaningless scramble of words,

00:39:30.980 | but it described a kind of mundane set of circumstances.

00:39:35.140 | Maybe it would be a story about someone

00:39:36.740 | who walked into a room, sat down at a desk,

00:39:39.520 | wrote for a little bit, then got up and had lunch,

00:39:42.080 | just kind of mundane information, not very interesting.

00:39:45.700 | Another group of subjects read also

00:39:48.620 | a 12-sentence paragraph, but that paragraph

00:39:51.940 | included a subset of sentences

00:39:54.600 | that had a lot of emotionally intense language,

00:39:58.040 | or that had language that could evoke

00:40:00.520 | an emotionally intense response in the person reading it.

00:40:03.320 | So it might've talked about a car accident

00:40:05.420 | or a very intense surgery,

00:40:07.600 | but it also could be positive stuff,

00:40:09.740 | things like a birthday party

00:40:12.240 | or a celebration of some other kind or a big sports win.

00:40:15.560 | So in other words, you have two conditions of this study,

00:40:18.420 | people either read a boring paragraph

00:40:20.700 | or they read a really emotionally laden paragraph.

00:40:23.500 | And again, the emotions could either be positive

00:40:25.700 | or negative emotions.

00:40:27.900 | Subjects left the laboratory and sometime later,

00:40:30.300 | they were called back to the laboratory.

00:40:32.040 | And I should say at no point in the experiment

00:40:34.700 | did they know they were part of a memory experiment, okay?

00:40:37.040 | They don't know why they're reading this paragraph.

00:40:39.020 | They came in either for class credit or to get paid.

00:40:41.700 | It's typically how these things are done

00:40:42.900 | on college campuses or elsewhere.

00:40:45.180 | They come back into the lab

00:40:46.860 | and they would get a pop quiz.

00:40:49.620 | They would be asked to recall the content of the paragraph

00:40:53.520 | that they had read previously.

00:40:55.700 | As is probably expected, perhaps even obvious to you,

00:40:58.880 | the subjects that read the emotionally intense paragraph

00:41:03.700 | remembered far more of the content of that paragraph

00:41:06.500 | and were far more accurate

00:41:08.900 | in their remembering of that information.

00:41:11.660 | Now, that particular finding wasn't very novel.

00:41:15.460 | Many people had previously described

00:41:17.380 | how emotionally intense events are better remembered

00:41:20.540 | than non-emotionally intense events.

00:41:22.780 | In fact, way back in the 1600s, Francis Bacon,

00:41:25.600 | who's largely credited with developing the scientific method

00:41:29.320 | said, quote, "Memory is assisted by anything

00:41:32.040 | "that makes an impression on a powerful passion,

00:41:34.200 | "inspiring fear, for example, or wonder, shame, or joy."

00:41:38.400 | Francis Bacon said that in 1620.

00:41:40.860 | So Jim McGaugh and Larry Cahill

00:41:42.700 | were certainly not the first to demonstrate

00:41:46.180 | or to conceive of the idea

00:41:47.700 | that emotionally laden experiences

00:41:50.060 | are more easily remembered than other experiences.

00:41:53.460 | However, what they did next was immensely important

00:41:56.800 | for our understanding of memory

00:41:58.300 | and for our building of tools

00:42:00.900 | to enhance learning and memory.

00:42:03.400 | What they did was they evaluated the capacity for stress

00:42:08.220 | and for particular neurochemicals associated with stress

00:42:11.460 | to improve our ability to learn information,

00:42:14.380 | not just information that is emotional,

00:42:17.620 | but information of all kinds.

00:42:19.940 | So I'm going to describe some experiments

00:42:21.380 | done in animal models just very briefly,

00:42:23.420 | and then experiments done on human subjects,

00:42:26.620 | because McGaugh worked mainly on animals,

00:42:28.900 | also human subjects,

00:42:30.080 | Larry Cahill almost exclusively on human subjects.

00:42:32.960 | If you take a rat or a mouse and put it in an arena

00:42:38.480 | where at one location the animal receives an electrical shock

00:42:42.440 | and then you come back the next day,

00:42:44.600 | you remove the shock evoking device

00:42:47.280 | and you let the animal move around that arena,

00:42:49.480 | that animal will quite understandably avoid the location

00:42:52.600 | where it was shocked, so-called conditioned place aversion.

00:42:56.300 | That effect of avoiding that particular location

00:43:00.640 | occurs in one trial.

00:43:01.780 | That's a good example of one trial learning.

00:43:03.920 | So somehow the animal knows

00:43:05.960 | that it was shocked at that location.

00:43:08.160 | It remembers that it is a hippocampal dependent learning.

00:43:12.260 | So animals that lack a hippocampus

00:43:14.160 | or who have their hippocampus pharmacologically

00:43:16.240 | or otherwise incapacitated

00:43:18.600 | will not learn that new bit of information.

00:43:21.880 | But for animals that do,

00:43:24.060 | they remember it after the first time and every time,

00:43:27.680 | unless you are to block the release of certain chemicals

00:43:32.080 | in the brain and body.

00:43:32.960 | And the chemicals I'm referring to are epinephrine,

00:43:36.280 | adrenaline, and to some extent the corticosterones,

00:43:40.080 | things like cortisol.

00:43:41.720 | Now we know that the effect of getting one trial learning

00:43:44.360 | somehow involves epinephrine,

00:43:46.320 | at least in this particular experimental scenario,

00:43:49.160 | because if researchers do the exact same experiment

00:43:52.880 | and they have done the exact same experiment,

00:43:54.860 | but they introduce a pharmacological blocker of epinephrine

00:43:59.400 | so that epinephrine is released in response to the shock,

00:44:02.440 | but it cannot actually bind to its receptors

00:44:05.200 | and have all of its biological effects.

00:44:07.360 | Well, then the animal is perfectly happy to tread back

00:44:10.400 | into the area where it received the shock.

00:44:12.680 | It's almost as if it didn't know,

00:44:14.280 | or we have to assume that didn't remember

00:44:17.140 | that it received the shock at that location.

00:44:19.680 | So it all seems pretty obvious when you hear it,

00:44:21.380 | something bad happens in a location,

00:44:22.640 | you don't go back to that location.

00:44:24.140 | So that's conditioned place avoidance,

00:44:26.380 | but it turns out that the opposite is also true,

00:44:29.160 | meaning for something called conditioned place preference,

00:44:32.400 | you can take an animal, put it into an arena,

00:44:34.760 | feed it or reward it somehow at one location in that arena.

00:44:38.760 | So you can give a hungry rat or mouse food

00:44:41.040 | at one particular location, take the animal out,

00:44:44.280 | come back the next day, no food is introduced,

00:44:46.580 | but it'll go back to the location where it received the food

00:44:49.160 | or you can do any variant of this.

00:44:50.680 | You can make the arena a little bit chilly

00:44:52.240 | and provide warmth at that location,

00:44:54.260 | or you can take a male animal and turns out male rats

00:44:59.040 | and mice will mate at any point or a female animal

00:45:01.360 | that's at the particular so-called receptive phase

00:45:03.200 | of her mating cycle and give them an opportunity

00:45:05.320 | to mate at a given location,

00:45:06.520 | they'll go back to that location and wait and wait.

00:45:08.180 | This is perhaps why people go back to the same bar,

00:45:10.520 | the bar, seat at the bar or the same restaurant

00:45:12.560 | and wait because of the one time they, you know,

00:45:14.880 | things worked out for them, whatever the context was.

00:45:18.240 | Conditioned place preference.

00:45:19.880 | Conditioned place preference,

00:45:22.960 | as with conditioned place avoidance,

00:45:25.200 | depends on the release of adrenaline, right?

00:45:28.240 | It's not just about stress,

00:45:30.200 | it's about a heightened emotional state in the brain

00:45:33.480 | and body, okay, this is really important.

00:45:35.460 | It's not just about stress.

00:45:37.240 | You can get one trial learning for positive events,

00:45:39.520 | conditioned place preference,

00:45:40.920 | and you can get one trial learning for negative events.

00:45:45.560 | Here I say positive, negative,

00:45:47.280 | I'm putting what's called valence on,

00:45:48.720 | I'm making a value judgment about whether or not

00:45:50.880 | the animal liked it or didn't like it,

00:45:52.340 | and we have to presume what the animal liked or didn't like

00:45:55.200 | and how it felt,

00:45:56.040 | but this turns out all to be true for humans as well.

00:45:59.840 | We know that because McGaugh and Cahill did experiments

00:46:03.420 | where they gave people a boring paragraph to read

00:46:07.000 | and only a boring paragraph to read,

00:46:09.360 | but one group of subjects was asked to read the paragraph

00:46:13.320 | and then to place their arm into very, very cold water.

00:46:17.600 | In fact, it was ice water.

00:46:19.160 | We know that placing one's arm into ice water,

00:46:21.520 | especially if it's up to the shoulder or near to it,

00:46:25.080 | evokes the release of adrenaline in the body.

00:46:27.480 | It's not an enormous release,

00:46:28.780 | but it's a significant increase.

00:46:30.360 | And yes, they measured adrenaline release.

00:46:32.920 | In some cases,

00:46:33.760 | they also measured for things like cortisol, et cetera.

00:46:36.440 | And what they found is that if one evokes the release

00:46:40.980 | of adrenaline through this arm into ice water approach,

00:46:45.760 | the information that they read previously,

00:46:47.880 | just a few minutes before, was remembered.

00:46:51.120 | It was retained as well as emotionally intense information,

00:46:55.400 | but keep in mind that information that they read

00:46:57.060 | was not interesting at all,

00:46:58.120 | or at least it wasn't emotionally laden.

00:47:00.980 | This had to be the effect of adrenaline released

00:47:03.800 | into the brain and body,

00:47:05.180 | because if they blocked the release or the function

00:47:09.840 | of adrenaline in the brain and or body,

00:47:13.260 | they could block this effect.

00:47:14.620 | Now, the biology of epinephrine and cortisol

00:47:17.840 | are a little bit complex,

00:47:18.900 | but there's some nuance there that's actually interesting

00:47:21.080 | and important to us.

00:47:22.020 | First of all, adrenaline is released in the body

00:47:25.300 | and in the brain.

00:47:26.140 | It's released in the body from the adrenals,

00:47:28.060 | remember epinephrine and adrenaline are the same thing.

00:47:31.040 | Cortisol is also released from the adrenal glands,

00:47:33.100 | these two little glands that ride atop our kidneys,

00:47:35.600 | but it can't cross into the brain.

00:47:37.460 | It only has what we call peripheral effects,

00:47:39.280 | quickening of the heart rate, right?

00:47:41.080 | Changes the patterns of blood flow,

00:47:43.640 | changes our patterns of breathing,

00:47:45.040 | in general makes our breathing more shallow and faster,

00:47:47.800 | in general makes our heartbeat more quickly, et cetera.

00:47:51.360 | Within our brain, we have a little brain area

00:47:53.240 | called locus coeruleus, which is in the back of the brain,

00:47:55.620 | which has the opportunity to sprinkler the rest of the brain

00:47:58.600 | with the neuromodulator epinephrine, adrenaline,

00:48:01.360 | as well as norepinephrine, a related neuromodulator,

00:48:04.240 | and to essentially wake up or create a state of alertness

00:48:07.520 | throughout the brain, so it's a very general effect.

00:48:10.600 | The reason we have two sites of release

00:48:12.840 | is because these neurochemicals

00:48:15.760 | do not cross the blood-brain barrier,

00:48:17.900 | and so waking up the body with adrenaline

00:48:20.520 | and waking up the brain are two separate

00:48:22.360 | so-called parallel phenomena.

00:48:24.500 | Cortisol can cross the blood-brain barrier

00:48:27.200 | because it's lipophilic,

00:48:28.600 | meaning it can move through fatty tissue,

00:48:31.640 | and we'll get into the biology of that in another episode,

00:48:34.240 | but cortisol in general is released

00:48:36.280 | and has much longer term effects,

00:48:37.920 | and as I've just told you,

00:48:38.960 | can permeate throughout the brain and body.

00:48:40.760 | Adrenaline has more local effects,

00:48:42.380 | or at least is segregated between the brain and the body.

00:48:45.220 | This will turn out to be important later.

00:48:47.280 | The important thing to keep in mind

00:48:48.480 | is that it is the emotionality evoked by an experience,

00:48:53.020 | or to be more precise,

00:48:55.020 | it is the emotional state that you are in

00:48:57.620 | after you experience something

00:49:00.960 | that dictates whether or not

00:49:02.200 | you will learn it quickly or not.

00:49:04.600 | This is absolutely important

00:49:06.880 | in terms of thinking about tools to improve your memory,

00:49:09.520 | and no, I am not going to suggest

00:49:11.320 | that every time you want to learn something,

00:49:12.620 | you plunge your arm into ice water.

00:49:15.200 | Why won't I suggest that?

00:49:16.480 | Well, it will induce the release of adrenaline,

00:49:20.600 | but there are better ways to get that adrenaline release.

00:49:22.980 | Before I explain exactly what those tools are,

00:49:25.460 | I want to tamp down the biology of how all this works,

00:49:28.560 | because in that understanding,

00:49:30.580 | you will have access to the best possible tools

00:49:33.400 | to improve your memory.

00:49:35.240 | First of all, McGaugh and Cahill

00:49:37.360 | were excellent experimentalists.

00:49:38.880 | They did not just establish

00:49:40.820 | that you could quicken the formation of a memory

00:49:44.720 | by accessing material that was very emotionally laden

00:49:48.000 | or creating an emotional high adrenaline state

00:49:51.120 | after interacting with some thing,

00:49:54.320 | some word, some person, some information.

00:49:57.160 | They also tested whether or not

00:49:58.960 | that whole effect could be blocked

00:50:00.900 | by blocking the emotional state or by blocking adrenaline.

00:50:04.160 | So what they did is they had people read paragraphs

00:50:05.880 | that either had a lot of emotional content

00:50:09.000 | or they had people read paragraphs that were pretty boring,

00:50:11.980 | but then had them put their arm into ice water.

00:50:14.600 | And I should say they did other experiments too

00:50:16.320 | to increase adrenaline.

00:50:17.400 | There were even some shock experiments

00:50:18.700 | that were done by other groups,

00:50:20.240 | any number of things to evoke the release of adrenaline,

00:50:22.180 | even people taking drugs that increase adrenaline.

00:50:24.720 | But then they also did what are called blocking experiments.

00:50:29.020 | They did experiments where they had people

00:50:31.340 | get into a highly emotional state

00:50:33.280 | from reading highly emotional material,

00:50:35.640 | or they got people to get into

00:50:36.800 | a highly emotional neurochemical state

00:50:38.600 | by reading boring material

00:50:39.880 | and then taking a drug to increase adrenaline

00:50:42.480 | or ice bath or a shock.

00:50:44.320 | And then they also administered a drug

00:50:47.120 | called a beta blocker to block the effect of adrenaline

00:50:50.840 | and related chemicals in the brain and body.

00:50:52.960 | And what they found is that

00:50:55.360 | even if people were exposed to something really emotional

00:50:58.920 | or had a lot of adrenaline in their system

00:51:02.200 | because they received a drug

00:51:03.240 | to increase the amount of adrenaline,

00:51:04.520 | two manipulations that normally would increase memory,

00:51:06.640 | keep that in mind,

00:51:08.040 | if they gave them a beta blocker,

00:51:10.480 | which reduced the response to that adrenaline, right?

00:51:13.540 | So no quickening of the heart rate,

00:51:14.840 | no quickening of the breathing,

00:51:16.840 | no increase in the activity of locus coeruleus

00:51:20.080 | and these kind of wake up signals to the rest of the brain.

00:51:22.700 | Well, then the material wasn't remembered better at all.

00:51:26.000 | What this tells us is that yes, Francis Bacon was right.

00:51:29.080 | McGaugh and Cahill were right.

00:51:30.560 | Hundreds, if not thousands of philosophers

00:51:32.680 | and psychologists and neuroscientists were right

00:51:35.680 | in stating and in thinking that high emotional states

00:51:40.380 | help you learn things.

00:51:42.060 | But what McGaugh and Cahill really showed

00:51:45.000 | and what's most important to know

00:51:47.000 | is that it is the presence of high adrenaline,

00:51:51.840 | high amounts of norepinephrine and epinephrine

00:51:54.600 | and perhaps cortisol as well, as you'll soon see,

00:51:58.160 | that allows a memory to be stamped down quickly.

00:52:01.920 | It is not the emotion.

00:52:05.360 | It is the neurochemical state that you go into

00:52:08.120 | as a consequence of the emotion.

00:52:10.480 | And it's very important to understand

00:52:11.720 | that while those two things are related,

00:52:13.400 | they are not one and the same thing.

00:52:15.740 | Because what that means is that were you to evoke

00:52:20.040 | the release of epinephrine, norepinephrine and cortisol,

00:52:23.640 | or even just one or two of those chemicals,

00:52:27.100 | after experiencing something,

00:52:29.200 | you are stamping down the experience

00:52:32.120 | that you just previously had.

00:52:34.200 | This is fundamentally important and far and away different

00:52:38.120 | than the idea that we remember things

00:52:41.280 | because they are important to us

00:52:42.840 | or because they evoke emotion.

00:52:44.240 | That's true, but the real reason, the neurochemical reason,

00:52:47.620 | the mechanism behind all that

00:52:49.560 | is these neurochemicals have the ability

00:52:52.480 | to strengthen neural connections

00:52:54.720 | by making them active just once.

00:52:57.440 | There's something truly magic

00:52:58.920 | about that neurochemical cocktail

00:53:00.740 | that removes the need for repetition.

00:53:03.180 | Okay, so let's apply this knowledge.

00:53:04.720 | Let's establish a scientifically grounded set of tools,

00:53:08.240 | meaning tools that take into account

00:53:10.880 | the identity of the neurochemicals

00:53:13.040 | that are important for enhancing learning

00:53:15.520 | and the timing of the release of those chemicals

00:53:18.060 | in order to enhance learning.

00:53:20.220 | When I first learned about the results of McGaugh and Cahill,

00:53:23.520 | I was just blown away.

00:53:25.660 | I was also pretty upset, but not with them.

00:53:28.360 | I was upset with myself because I realized

00:53:30.440 | that the way that I'd been approaching learning and memory

00:53:33.000 | was not optimal.

00:53:34.480 | In fact, it was probably in the opposite direction

00:53:37.780 | to the enhanced protocol for learning and memory

00:53:40.680 | that I'm going to teach you today.

00:53:43.080 | My typical mode of trying to learn something

00:53:44.920 | while I was in college or while I was in graduate school,

00:53:47.960 | or as a junior professor or even a tenured professor

00:53:51.200 | was to sit down to whatever it is

00:53:53.600 | I was going to try and learn, perhaps even memorize,

00:53:56.600 | or if it was a physical skill,

00:53:58.040 | move to whatever environment

00:53:59.540 | I was going to learn that physical skill in.

00:54:01.520 | And prior to that, to make sure that I was hydrated,

00:54:05.680 | 'cause that's important to me,

00:54:06.880 | and certainly can contribute to your brain's ability

00:54:09.720 | to function and your body's ability to function

00:54:11.960 | and general patterns of alertness, but also to caffeinate.

00:54:16.080 | I would have a nice strong cup of coffee or espresso.

00:54:19.420 | I would have a nice strong cup of yerba mate.

00:54:22.020 | And I still drink coffee or yerba mate very regularly.

00:54:27.000 | I drink them in moderation, I think, certainly for me,

00:54:30.360 | but typically I would drink those things

00:54:33.520 | before I would engage in any kind of attempt

00:54:36.220 | to learn or memorize or to acquire a new skill.

00:54:39.240 | Now, caffeine in the form of coffee or yerba mate

00:54:43.120 | or any other form of caffeine

00:54:45.120 | does create a sense of alertness in our brain and body.

00:54:47.400 | And it does that through two major mechanisms.

00:54:49.680 | The first mechanism is by blocking the effects of adenosine.

00:54:54.080 | Adenosine is a molecule that builds up in the brain and body

00:54:56.360 | the longer that we are awake.

00:54:57.880 | And it's largely what's responsible

00:54:59.600 | for our feelings of sleepiness and fatigue

00:55:02.140 | when we've been awake for a very long time.

00:55:05.240 | Caffeine essentially acts to block the effects of adenosine.

00:55:10.240 | It's a competing agonist, not to get technical,

00:55:13.600 | but it binds to the receptor for adenosine

00:55:16.240 | for some period of time and prevents adenosine

00:55:18.120 | from having its normal pattern of action

00:55:20.120 | and thereby reduces our feelings of fatigue.

00:55:23.800 | But it also increases state of alertness.

00:55:26.580 | So while it's reducing fatigue,

00:55:28.800 | it's also pushing on neurochemical systems

00:55:31.000 | in order to directly increase our alertness.

00:55:32.720 | And it does that in large part by increasing

00:55:35.760 | the transmission of epinephrine,

00:55:37.600 | adrenaline in the brain and body.

00:55:39.560 | It also has this interesting effect

00:55:41.040 | of upregulating the number and or efficiency,

00:55:44.040 | or we say the efficacy of dopamine receptors,

00:55:48.180 | such that when dopamine is present

00:55:50.720 | and as a molecule that increases motivation

00:55:52.680 | and craving and pursuit,

00:55:54.080 | that dopamine can have a more potent effect

00:55:56.080 | than it would otherwise.

00:55:57.200 | So caffeine really hits these three systems.

00:55:59.240 | It hits other systems too,

00:56:00.240 | but it mainly reduces fatigue by reducing adenosine,

00:56:03.720 | increases alertness by increasing epinephrine release

00:56:07.200 | or adrenaline release,

00:56:08.200 | I should say both from the adrenals in your body

00:56:10.140 | and from locus coeruleus within the brain.

00:56:12.720 | And it can in parallel to all that increase the action

00:56:16.920 | or the efficacy of the action of dopamine.

00:56:20.160 | So my typical way of approaching learning and memory

00:56:22.780 | would be to drink some caffeine and then focus really hard

00:56:25.760 | on whatever it is that I'm trying to learn,

00:56:27.480 | trying to eliminate distractions and then hope, hope, hope,

00:56:31.440 | or try, try, try to remember that information

00:56:33.800 | as best as I could.

00:56:35.440 | And frankly, I felt like it was working pretty well for me.

00:56:37.680 | And typically if I leveraged other forms of pharmacology

00:56:40.420 | in order to enhance learning and memory,

00:56:43.100 | things like alpha GPC or phosphatidylserine,

00:56:47.440 | I would do that by taking those things

00:56:50.160 | before I sat down to learn a particular set of information

00:56:54.000 | or before I went off to learn a particular physical skill.

00:56:58.040 | Now, for those of you out there listening to this,

00:57:00.260 | you're probably thinking, well, okay,

00:57:03.120 | the results of McGaugh and Cahill pointed to the fact

00:57:05.880 | that having adrenaline released after learning something

00:57:10.560 | enhanced learning of that thing.

00:57:12.540 | But a lot of these things like caffeine or alpha GPC

00:57:15.880 | can increase epinephrine and adrenaline or dopamine

00:57:20.080 | or other molecules in the brain and body

00:57:23.440 | that can enhance memory for a long period of time.

00:57:25.700 | So it makes sense to take it first or even during learning

00:57:28.720 | and then allow that increase to occur.

00:57:31.020 | And the increase will occur over a long period of time

00:57:33.040 | and will enhance learning and memory.

00:57:35.260 | And while that is partially true, it is not entirely true.

00:57:39.560 | And it turns out it's not optimal.

00:57:41.820 | Work that was done by the McGaugh laboratory

00:57:44.160 | and other laboratories evaluated

00:57:47.400 | the precise temporal relationship

00:57:50.140 | between neurochemical activation of these pathways

00:57:54.100 | and learning and memory.

00:57:55.280 | What they did is they had animals and or people,

00:57:57.540 | depending on the experiment, take a drug, could be caffeine,

00:58:01.520 | could be in pill form,

00:58:03.620 | something that would increase adrenaline

00:58:06.700 | or related molecules that create this state of alertness

00:58:10.180 | that are related to emotionality.

00:58:12.100 | And they had them do it either an hour before,

00:58:14.420 | 30 minutes before, 10 minutes before,

00:58:17.380 | five minutes before learning

00:58:20.100 | or during the bout of learning, right?

00:58:23.100 | The reading of the information

00:58:24.240 | or the performing of the skill that one is trying to learn,

00:58:26.220 | or five minutes, 10 minutes, 15 minutes,

00:58:28.820 | 30 minutes, et cetera, afterwards.

00:58:30.900 | So they looked very precisely at when exactly is best

00:58:33.980 | to evoke this adrenaline release.

00:58:35.940 | And it turns out that the best time window

00:58:38.260 | to evoke the release of these chemicals,

00:58:40.660 | if the goal is to enhance learning

00:58:42.820 | and memory of the material is either immediately after

00:58:46.660 | or just a few minutes, five, 10, maybe 15 minutes

00:58:50.840 | after you're repeating that information,

00:58:53.920 | you're trying to learn that information.

00:58:55.380 | Again, this could be cognitive information

00:58:57.180 | or this could be a physical skill.

00:58:59.200 | Now, this really spits in the face of the way

00:59:01.680 | that most of us approach learning and memory.

00:59:03.980 | Most of us, if we use stimulants like caffeine or alpha GPC,

00:59:08.980 | we're taking those before or during an attempt to learn,

00:59:13.140 | not afterwards.

00:59:15.460 | These results point to the fact

00:59:16.940 | that it is after the learning and memory

00:59:19.800 | that you really want to get that big increase

00:59:22.140 | in epinephrine and the related molecules

00:59:24.460 | that will tamp down memory.

00:59:25.880 | So what this means is that if you are currently using

00:59:28.540 | caffeine or other compounds,

00:59:30.540 | and we'll talk about what those are

00:59:31.840 | and safety issues and so forth in a moment,

00:59:34.620 | if you're using those compounds

00:59:36.780 | in order to enhance learning and memory

00:59:38.420 | by taking them before or during a learning episode,

00:59:42.560 | well, then I encourage you to try and take them either late

00:59:46.040 | in the learning episode

00:59:47.340 | or immediately after the learning episode.

00:59:49.880 | Now, given everything I've told you up until now,

00:59:51.560 | why would I say late in the learning episode

00:59:53.440 | or immediately after?

00:59:54.560 | Well, when you ingest something by drinking it

00:59:57.160 | or you take it in capsule form,

00:59:58.680 | there's a period of time

00:59:59.520 | before that gets absorbed into the body

01:00:01.040 | and different substances such as caffeine,

01:00:03.800 | alpha GPC, et cetera,

01:00:05.160 | are absorbed in from the gut and into the bloodstream

01:00:08.040 | and reach the brain and trigger these effects

01:00:10.100 | in the brain and body at different rates.

01:00:11.600 | And so it's not instantaneous.

01:00:13.280 | Some have effects within minutes,

01:00:14.880 | others within tens of minutes and so on.

01:00:18.320 | It's really going to depend on the pharmacology

01:00:20.600 | of those things.

01:00:21.440 | And it's also going to depend on whether or not

01:00:22.720 | you have food in your gut,

01:00:23.720 | what else you happen to have circulating

01:00:25.160 | in your bloodstream, et cetera.

01:00:26.800 | But at a very basic level,

01:00:28.240 | we can confidently say that there are not one, not dozens,

01:00:32.640 | but as I mentioned before,

01:00:33.680 | hundreds of studies in animals and in humans

01:00:35.880 | that point to the fact that triggering the increase

01:00:37.740 | of adrenaline late in learning

01:00:39.960 | or immediately after learning is going to be most beneficial

01:00:42.640 | if your goal is to retain that information

01:00:44.760 | for some period of time

01:00:45.920 | and to reduce the number of repetitions required

01:00:48.140 | in order to learn that information.

01:00:49.920 | Now, I want to acknowledge that on previous episodes

01:00:52.340 | of this podcast and in appearing on other podcasts,

01:00:56.120 | I've talked a lot about things like non-sleep deep rest

01:00:58.920 | and naps and sleep as vital to the learning process.

01:01:01.960 | And I want to emphasize

01:01:02.960 | that none of that information has changed, right?

01:01:05.420 | I don't look at any of that information differently

01:01:07.320 | as the consequence of what I'm talking about today.

01:01:09.760 | It is still true that the strengthening of connections

01:01:12.680 | in the brain, the literal neuroplasticity,

01:01:15.460 | the changing of the circuits occurs during deep sleep

01:01:17.840 | and non-sleep deep rest.

01:01:19.680 | And it is also true,

01:01:20.960 | and I've mentioned these results earlier,

01:01:22.840 | that two papers were published in Cell Reports,

01:01:25.720 | Cell Press Journal, excellent journal

01:01:27.480 | over the last few years showing that brief naps

01:01:30.840 | of about 20 to up to 90 minutes in some period of time

01:01:35.800 | after an attempt to learn can enhance the rate of learning

01:01:39.720 | and memory.

01:01:41.360 | However, those bouts of sleep,

01:01:44.720 | the deep sleep that night, I should say,

01:01:46.320 | or those brief naps, or even the so-called NSDR,

01:01:49.680 | as we call it, non-sleep deep rest that was used

01:01:52.200 | to enhance the learning and memory

01:01:54.800 | of particular pieces of information,

01:01:57.360 | either cognitive or physical information or both,

01:02:00.960 | that still can be performed,

01:02:03.420 | but it can be performed some hours later, even an hour later

01:02:08.440 | it can be performed two hours later or four hours later.

01:02:11.020 | Remember, it's in these naps and in deep sleep

01:02:13.360 | that the actual reconfiguration of the neural circuits

01:02:15.700 | occurs, the strengthening of those neural circuits occurs.

01:02:18.940 | It is not the case that you need to finish a bout

01:02:21.440 | of learning and drop immediately into a nap or sleep.

01:02:23.520 | Some people might do that,

01:02:24.800 | but if you're really trying to optimize and enhance

01:02:27.300 | and improve your memory, the data from McGaugh and Cahill

01:02:31.080 | and many other laboratories that stemmed out

01:02:33.660 | from their initial work really point to the fact

01:02:36.120 | that the ideal protocol would be focus on the thing

01:02:40.040 | you're trying to learn very intensely.

01:02:41.600 | There are also some other things like error rates, et cetera.

01:02:44.220 | Please see our episodes on learning.

01:02:45.780 | We have a newsletter on how to learn better.

01:02:48.320 | You can access that at hubermanlab.com.

01:02:50.000 | It's a zero cost newsletter.

01:02:51.720 | You can grab that PDF.

01:02:53.240 | It lists out the things to do during the learning bout.

01:02:56.800 | Still try and get excellent sleep.

01:02:59.280 | Again, fundamentally important for mental health,

01:03:01.120 | physical health, and performance.

01:03:02.580 | And we can now extend from performance to saying,

01:03:05.300 | including learning and memory, nap,

01:03:08.540 | if it doesn't interrupt your nighttime sleep,

01:03:10.880 | naps of anywhere from 10 to 90 minutes

01:03:13.380 | or non-sleep-depress protocols

01:03:14.980 | will enhance learning and memory.

01:03:16.400 | But we can now add to that that spiking adrenaline,

01:03:20.720 | provided it can be done in a safe way,

01:03:22.800 | is going to reduce the number of repetitions

01:03:25.280 | required to learn.

01:03:26.120 | And that should be done at the very tail end

01:03:28.520 | or immediately after a learning bout,

01:03:30.720 | which is compatible with all the other protocols

01:03:33.360 | that I mentioned.

01:03:34.200 | And the reason I'm revisiting the stuff about sleep

01:03:36.200 | and non-sleep-depress

01:03:37.540 | is I think that some people got the impression

01:03:39.040 | that they need to do that immediately after learning.

01:03:41.080 | And today I'm saying to the contrary,

01:03:42.640 | immediately after learning,

01:03:43.780 | you need to go into a heightened state of emotionality

01:03:46.540 | and alertness.

01:03:47.400 | Now it's vitally important to point out

01:03:49.840 | that you do not need pharmacology.

01:03:52.560 | You don't need caffeine.

01:03:54.460 | You don't need alpha GPC.

01:03:56.680 | You don't need any pharmacologic substance

01:03:58.820 | to spike adrenaline,

01:04:00.620 | unless that's something that you already are doing

01:04:03.300 | or that you can do safely

01:04:05.000 | or that you know that you can do safely.

01:04:06.680 | And I always say, and I'll say it again,

01:04:09.160 | I'm not a physician, so I'm not prescribing anything.

01:04:11.120 | I'm a professor, so I profess things.

01:04:13.200 | You need to do what's safe for you.

01:04:14.800 | So if you're somebody who's not used to drinking caffeine

01:04:17.140 | and you suddenly drink four espresso

01:04:19.040 | after trying to learn something,

01:04:20.580 | you are going to have a severe increase in alertness

01:04:25.580 | and probably even anxiety.

01:04:26.760 | If you're panic attack prone,

01:04:28.260 | please don't start taking stimulants

01:04:30.240 | in order to learn things better.

01:04:31.720 | Please be safe.

01:04:32.560 | I don't just say that to protect me.

01:04:33.580 | I say that to protect you.

01:04:35.020 | And I should mention that if you're not accustomed

01:04:38.280 | to taking something,

01:04:39.520 | you always want to first check with your doctor, of course,

01:04:42.200 | but also move into that gradually, right?

01:04:45.040 | Start with the lowest effective dose,

01:04:47.700 | the minimal effective dose.

01:04:49.240 | And sometimes the minimal effective dose is zero milligrams.

01:04:53.240 | It's nothing.

01:04:54.400 | Why do I say that?

01:04:55.240 | Well, we already talked about results

01:04:57.480 | where they put people's arms into an ice bath

01:05:01.260 | in order to evoke adrenaline release.

01:05:02.880 | You are welcome to do that if you want.

01:05:04.320 | In fact, that's a pretty low cost, zero pharmacology,

01:05:07.640 | at least exogenous pharmacology way

01:05:09.280 | to approach this whole thing.

01:05:11.040 | That's a way of evoking your own natural epinephrine.

01:05:13.960 | And it turns out also dopamine release.

01:05:16.480 | You could take a cold shower.

01:05:18.200 | You could do an ice bath or get into a cold circulating bath.

01:05:21.880 | We've done several episodes on the utility of cold

01:05:24.920 | for health and performance.

01:05:25.800 | You can find those episodes at huberunelab.com.

01:05:28.080 | Also the episode with my colleague at Stanford

01:05:30.800 | from the biology department, Dr. Craig Heller,

01:05:33.060 | lots of protocols in particular,

01:05:34.780 | in the episode on cold for health and performance

01:05:37.700 | that describe how best to use the cold shower

01:05:41.980 | or the ice bath or the circulating cold bath

01:05:44.620 | in order to evoke epinephrine and dopamine release.

01:05:47.320 | The point is that the time in which you would want

01:05:50.980 | to do those protocols is after,

01:05:53.100 | ideally immediately after you're learning about,

01:05:56.280 | meaning when you're sitting down to learn new information

01:05:58.500 | or after trying to learn some new physical skill.

01:06:01.280 | Now, whether or not that's compatible

01:06:02.460 | with the other reasons you're doing deliberate cold exposure

01:06:05.880 | and whether or not that's compatible

01:06:07.280 | with the other things you're doing,

01:06:08.320 | that depends on the contour of your lifestyle,

01:06:10.080 | your training, your academic goals,

01:06:11.440 | your learning goals, et cetera.

01:06:12.840 | But if your specific purpose is to enhance learning

01:06:15.880 | and memory, you want to spike adrenaline afterwards.

01:06:17.920 | And so what I'm telling you is you can do that with caffeine.

01:06:20.680 | You can do that with alpha GPC.

01:06:22.780 | You can do that with a combination of caffeine and alpha GPC

01:06:25.640 | if you can do that safely.

01:06:27.360 | Some of you I know are using other forms of pharmacology.

01:06:29.780 | I did a long episode all about ADHD.

01:06:32.260 | I have to just really declare my stance very clearly

01:06:35.660 | that I am not a fan.

01:06:37.780 | I am actually opposed to people using prescription drugs

01:06:42.220 | who are not prescribed those drugs, right?

01:06:44.480 | In order to enhance alertness,

01:06:45.960 | I think there's a big addictive potential.

01:06:47.720 | There also is a potential to really disrupt

01:06:50.140 | one's own pharmacology around the dopaminergic system.

01:06:53.820 | However, some of you I know are prescribed things

01:06:57.000 | like Ritalin, Adderall, and modafinil and things of that sort

01:07:00.960 | in order to increase alertness and focus.

01:07:02.960 | So for those of you that are prescribed those things

01:07:04.820 | from a board certified physician,

01:07:07.680 | you're going to have to decide if you're going to take them

01:07:09.240 | before trying to learn or after trying to learn.

01:07:12.040 | You also have to take into consideration

01:07:13.380 | that some of those drugs are very long acting,

01:07:15.440 | some are shorter acting and time that

01:07:17.960 | according to what you're trying to learn and when.

01:07:20.200 | So that's pharmacology.

01:07:21.800 | But as I've mentioned, there are the behavioral protocols.

01:07:24.800 | You can use cold and cold is an excellent stimulus

01:07:28.800 | because first of all, it doesn't involve pharmacology.

01:07:32.880 | Second of all, you can generally access it

01:07:35.680 | at low to zero cost, especially the cold shower approach.

01:07:39.360 | And third, you can titrate it.

01:07:41.960 | You can start with warmer water.

01:07:43.680 | You can make it very, very cold if that's your thing

01:07:45.980 | and you're able to tolerate that safely.

01:07:47.480 | You can make it moderately cold.

01:07:50.780 | How cold should it be in order to evoke adrenaline release?

01:07:53.560 | Well, it should be uncomfortably cold,

01:07:55.520 | but cold enough that you feel like you really want to get out

01:07:58.960 | but can stay in safely.

01:08:00.340 | That's going to evoke adrenaline release.

01:08:02.560 | If it quickens your breathing,

01:08:04.120 | if it makes you go wide-eyed,

01:08:06.040 | that's increasing adrenaline release.

01:08:07.520 | In fact, those effects of going wide-eyed

01:08:09.800 | and quickening of the breathing

01:08:10.800 | and the challenges and thinking clearly,

01:08:12.720 | those are the direct effects of adrenaline

01:08:14.360 | on your brain and body.

01:08:15.840 | And of course, there are other ways to increase adrenaline.

01:08:18.160 | You could go out for a hard run.

01:08:20.720 | You could do any number of things

01:08:22.820 | that would increase adrenaline in your body.

01:08:25.060 | Which things you choose is up to you.

01:08:27.440 | But from a very clear, solid grounding in research data,

01:08:32.400 | we can confidently say that spiking adrenaline

01:08:35.100 | after interacting with some material,

01:08:37.620 | physical or cognitive material that you're trying to learn

01:08:39.840 | is going to be the best time to spike that adrenaline.

01:08:42.380 | Now, I realize that I'm being a bit redundant today

01:08:44.240 | or perhaps a lot redundant in repeating over and over

01:08:47.700 | that the increase in epinephrine should occur

01:08:51.380 | either very late in an attempt to learn something

01:08:54.280 | or immediately after an attempt to learn something.

01:08:58.180 | I also want to emphasize the general contour

01:09:00.940 | of pharmacologic effects and of behavioral tools

01:09:03.640 | to create adrenaline.

01:09:04.880 | What do I mean by that sentence?

01:09:06.260 | What I mean is that McGaugh and colleagues

01:09:09.240 | explored a huge number of different compounds and approaches,

01:09:11.720 | everything from the hand into the ice bath

01:09:13.760 | to injecting adrenaline, to caffeine,

01:09:17.400 | to drugs that block the effects of adrenaline and caffeine,

01:09:22.320 | drugs like mucimol and picrotoxin, please don't take those.

01:09:25.160 | These are drugs that reduce or enhance

01:09:27.560 | the amount of adrenaline.

01:09:28.560 | And the overall takeaway is that anything

01:09:31.640 | that increases adrenaline will increase learning and memory

01:09:35.280 | and will reduce the number of repetitions

01:09:36.880 | required to learn something,

01:09:39.160 | regardless of whether or not that something

01:09:40.880 | has an emotional intensity or not.

01:09:44.800 | Provided that that spike in adrenaline occurs

01:09:47.740 | late in the learning or immediately after,

01:09:49.580 | and anything that reduces epinephrine and adrenaline

01:09:53.720 | will impair learning.

01:09:55.760 | And that's the key and novel piece of information

01:09:58.560 | that I'm adding now, which is if you're taking beta blockers,

01:10:01.960 | for instance, or if you're trying to learn something

01:10:05.560 | and it's not evoking much of an emotional response

01:10:08.960 | and you're not using any pharmacology or other methods

01:10:11.640 | to enhance adrenaline release after learning that thing,

01:10:14.780 | well, you're not going to learn it very well.

01:10:17.100 | In fact, McGaugh and Cahill did beautiful experiments

01:10:20.560 | in humans looking at how much adrenaline is increased

01:10:24.980 | by varying the emotional intensity of different things

01:10:29.280 | that they were trying to get people to learn

01:10:31.160 | or by changing the dosage of epinephrine

01:10:34.160 | or by changing the amount of epinephrine blocker

01:10:36.480 | that they injected, lots and lots of studies.

01:10:39.420 | The key thing to take away from those studies

01:10:41.160 | is that for some people,

01:10:42.680 | adrenaline was increased 600 to 700%.

01:10:46.280 | So six to seven fold over baseline

01:10:48.900 | in the amount of circulating epinephrine or adrenaline.

01:10:51.700 | And keep in mind, sometimes that increase

01:10:53.400 | was due to the actual thing they were trying to learn

01:10:55.500 | being very emotional, positive or negative emotion.

01:10:58.600 | And sometimes it was because they were using

01:11:00.260 | a pharmacologic approach or the ice bath approach.

01:11:02.900 | I don't think they ever used a cold shower approach,

01:11:04.560 | but that would have been a very effective one,

01:11:06.200 | we can be sure.

01:11:07.380 | However, other people had a zero to 10% increase

01:11:13.020 | or a very small increase in epinephrine.

01:11:15.140 | What we can confidently say on the basis of all those data

01:11:19.200 | is that the more epinephrine release,

01:11:22.660 | the better that people remembered the material.

01:11:25.820 | Over and over again, this was shown

01:11:27.200 | whether or not it was for cognitive materials,

01:11:29.100 | so learning a language, learning a passage of words,

01:11:31.760 | learning mathematics,

01:11:33.120 | or whether or not it was for physical learning.

01:11:35.780 | I want to emphasize something about physical learning

01:11:37.700 | because I know a number of you

01:11:39.100 | are probably drinking a cup of coffee

01:11:41.100 | or having a cup of yerba mate

01:11:42.620 | or maybe even an energy drink

01:11:43.900 | and taking some alpha GPC or something

01:11:45.620 | before physical exercise.

01:11:48.300 | I'm not saying that's a bad thing to do

01:11:49.820 | or that you wouldn't want to do that,

01:11:51.020 | but that's really to increase alertness.

01:11:53.360 | It won't enhance learning, at least not as well

01:11:55.800 | as doing those things after the physical exercise.

01:11:59.060 | Now, again, many of you, including myself,

01:12:01.620 | exercise for sake of the physical benefits

01:12:03.580 | of that exercise, so cardiovascular resistance training,

01:12:06.500 | but we're not really focused on learning and memory.

01:12:09.860 | So I emphasize this

01:12:12.460 | just so it's immensely clear to everybody.

01:12:14.420 | If you want to use those approaches

01:12:16.800 | of increasing adrenaline prior to

01:12:18.940 | or during physical training

01:12:20.820 | or cognitive work for that matter, be my guest.

01:12:23.380 | I think that's perfectly fine provided that's safe for you.

01:12:26.300 | It's only by moving it to late or after the learning

01:12:29.840 | that you're really shifting the role

01:12:32.020 | of that adrenaline increase

01:12:34.060 | to enhancing memory specifically.

01:12:36.540 | And as a cautionary note,

01:12:38.340 | don't think that you can push this entire system

01:12:40.860 | to the extreme over and over again,

01:12:42.740 | or chronically as we say, and get away with it.

01:12:45.420 | In other words, you're not going to be able to take

01:12:48.380 | a alpha GPC and a double espresso,

01:12:52.180 | do your focus bout of work, cognitive or physical work,

01:12:56.120 | and then spike adrenaline again afterwards

01:12:58.780 | and remember that stuff even better, right?

01:13:00.580 | I'm not encouraging you.

01:13:01.700 | In fact, I'm discouraging you

01:13:03.640 | from chronically increasing adrenaline

01:13:06.960 | both during and after a given bout of work

01:13:11.860 | if the goal is to learn.

01:13:13.440 | Why do I say that?

01:13:14.380 | Well, work from McGaugh and Cahill and others

01:13:17.600 | has shown that it's not the absolute amount

01:13:21.380 | of adrenaline that you release in your brain and body

01:13:24.040 | that matters for enhancing memory.

01:13:26.560 | It's the amount of adrenaline that you release

01:13:29.680 | relative to the amount of adrenaline

01:13:32.240 | that was in your system just prior,

01:13:34.300 | in particular in the hour or two prior.

01:13:36.320 | So again, it's the delta, as we say, it's the difference.

01:13:38.920 | So if you're going to chronically increase adrenaline,

01:13:41.180 | you're not going to learn as well.

01:13:43.160 | The real key is to have adrenaline modestly low,

01:13:45.860 | perhaps even just as much as you need

01:13:48.140 | in order to be able to focus on something,

01:13:50.000 | pay attention to it, and then spike it afterwards.

01:13:52.860 | This is immensely important

01:13:54.900 | because while much of what we're talking about

01:13:58.220 | is actually a form of inducing a neurochemical acute stress,

01:14:01.980 | meaning a brief and rapid onset of stress,

01:14:06.300 | well, chronic stress,

01:14:08.460 | the chronic elevation of epinephrine and cortisol

01:14:11.860 | is actually detrimental to learning.

01:14:13.620 | And there's an entire category of literature,

01:14:16.500 | mainly from the work of the great,

01:14:18.380 | and sadly the late Bruce McEwen

01:14:20.660 | from the Rockefeller University

01:14:22.000 | and some of his scientific offspring,

01:14:23.580 | like the great Robert Sapolsky,

01:14:25.660 | showing that chronic stress,

01:14:27.780 | chronic elevation of epinephrine

01:14:29.340 | actually inhibits learning and memory

01:14:31.460 | and also can inhibit immune system function,

01:14:33.380 | whereas acute, right, sharp increases in adrenaline

01:14:37.700 | and cortisol actually can enhance learning

01:14:39.980 | and indeed can enhance the immune system.

01:14:41.920 | So if you really want to leverage this information,

01:14:44.780 | you might consider getting your brain and body

01:14:47.580 | into a very calm and yet alert state,

01:14:50.780 | so a high attentional state that will allow you

01:14:52.780 | to focus on what it is that you're trying to learn.

01:14:55.180 | We know focus is vital for encoding information

01:14:58.320 | and for triggering neuroplasticity,

01:15:00.260 | but remaining calm throughout that time

01:15:02.980 | and then afterwards spiking adrenaline

01:15:05.860 | and allowing adrenaline to have these incredible effects

01:15:08.740 | on reducing the number of repetitions required to learn.

01:15:11.620 | So if you're like me,

01:15:12.700 | you're learning about this information,

01:15:14.180 | this beautiful work of McGaugh and Cahill and others

01:15:16.660 | and thinking, wow, I should perhaps consider

01:15:19.740 | spiking my adrenaline in one form or another

01:15:23.060 | at the tail end or immediately following

01:15:25.320 | in attempt to learn something.

01:15:27.220 | And yet we are not the first to have this conversation

01:15:30.020 | nor were McGaugh and Cahill or any other researchers

01:15:33.020 | that I've discussed today,

01:15:34.260 | the first to start using this technique.

01:15:37.780 | In fact, there is a beautiful review

01:15:40.120 | that was published just this year, May of 2022

01:15:42.740 | in the journal Neuron, Cell Press Journal,

01:15:44.460 | excellent journal called "Mechanisms of Memory Under Stress."

01:15:48.980 | And I just want to read to you the first opening paragraph

01:15:52.120 | of this review, which is, as the name suggests,

01:15:54.380 | all about memory and stress.

01:15:56.760 | So here I'm reading and I quote,

01:15:58.660 | "In medieval times, communities threw young children

01:16:01.580 | in the river when they wanted them

01:16:02.900 | to remember important events.

01:16:04.860 | They believed that throwing a child in the water

01:16:06.700 | after witnessing historic proceedings

01:16:08.980 | would leave a lifelong memory for the events in the child."

01:16:12.540 | Believe it or not, this is true.

01:16:14.400 | This is a practice that somehow people arrived at.

01:16:18.980 | I don't know if they were aware of what adrenaline was,

01:16:22.180 | probably not, but somehow in medieval times,

01:16:26.040 | it was understood that spiking adrenaline

01:16:28.860 | or creating a robust emotional experience

01:16:32.160 | after an experience that one hoped a child would learn

01:16:36.720 | would encourage the child's nervous system,

01:16:39.040 | and they didn't even know what a nervous system was,

01:16:40.420 | but would encourage the brain and body of that child

01:16:43.440 | to remember those particular events.

01:16:45.860 | Very counterintuitive, if you ask me.

01:16:48.880 | I would have thought that the kid would remember

01:16:50.680 | only being thrown into the river.

01:16:52.120 | My guess is that they remembered that,

01:16:53.520 | but that the idea here anyway

01:16:55.440 | is that they also remember the things

01:16:56.820 | that preceded being thrown into the river.

01:16:59.140 | So both interesting and amusing,

01:17:02.540 | and somewhat, I should say, thought stimulating, really,

01:17:06.620 | that this is a practice that has been going on

01:17:09.620 | for many hundreds of years,

01:17:11.680 | and we are not the first to start thinking

01:17:14.140 | about using cold water as an adrenaline stimulus,

01:17:16.780 | nor are we the first to start thinking

01:17:18.100 | about using cold water-induced adrenaline

01:17:20.780 | as a way to enhance learning and memory.

01:17:22.580 | This has been happening since medieval times.

01:17:25.320 | So up until now, I've been talking about

01:17:27.180 | a pretty broad contour of these experiments.

01:17:29.880 | I've been talking about the underlying pharmacology,

01:17:31.960 | the role of epinephrine, and so forth.

01:17:33.320 | I haven't really talked a lot

01:17:34.420 | about the underlying neural mechanisms,

01:17:36.260 | so I'm just going to take a minute or two

01:17:37.320 | and describe those for you because they are informative.

01:17:40.800 | We all have a brain structure called the amygdala.

01:17:43.540 | A lot of people think it's associated with fear,

01:17:45.560 | but it's actually associated with threat detection,

01:17:48.820 | and more generally, and I should say more specifically,

01:17:52.140 | with detecting what sorts of events in the environment

01:17:55.580 | are novel and are linked to particular emotional states,

01:17:59.480 | both positive emotional states

01:18:01.060 | and negative emotional states.

01:18:03.040 | So the neurons in the amygdala are exquisitely good

01:18:06.120 | at figuring out, right, they don't have their own mind,

01:18:09.280 | but at detecting correlations between sensory events

01:18:13.160 | in the environment that trigger the release of adrenaline

01:18:15.620 | and what's going on in the brain,

01:18:17.220 | and because the amygdala is so extensively interconnected

01:18:19.920 | with other areas of the brain,

01:18:21.280 | it basically connects to everything,

01:18:22.420 | and everything connects back to it,

01:18:24.180 | the amygdala is in a position

01:18:26.960 | to strengthen particular connections in the brain

01:18:30.380 | very easily, provided certain conditions are met,

01:18:34.400 | and those conditions are the ones we've been talking about

01:18:36.080 | up until now, emotional saliency that results in increases

01:18:39.600 | in epinephrine and cortisol,

01:18:41.400 | or circulating epinephrine and cortisol being much higher

01:18:44.440 | than it was 10 minutes or 15 minutes before,

01:18:46.800 | and the net effect of the amygdala in this context

01:18:49.440 | is to take whatever patterns of neural activity

01:18:52.160 | preceded that increase in adrenaline and corticosterone

01:18:55.200 | and strengthen those synapses

01:18:57.320 | that were involved in that neural activity.

01:18:59.200 | So the amygdala doesn't have knowledge,

01:19:01.120 | it's not a thinking area, it's a correlation detector,

01:19:05.400 | and it's correlating neurochemical states

01:19:07.160 | of the brain and body with different patterns

01:19:08.960 | of electrical activity in the brain.

01:19:11.440 | This is important because it really emphasizes the fact

01:19:15.280 | that both negative and positive emotional states

01:19:19.320 | and the different but somewhat overlapping chemical states

01:19:24.320 | that they create are the conditions, as we say,

01:19:27.260 | the AND gates through which memory is laid down.

01:19:30.760 | AND gates will be familiar to those of you

01:19:32.520 | who have done a bit of computer programming.

01:19:35.120 | An AND gate is simply a condition in which you need one thing

01:19:40.120 | and another to happen in order for a third thing to happen.

01:19:44.400 | So you need epinephrine elevated

01:19:46.080 | and you need robust activity in a particular brain circuit

01:19:49.260 | if in fact that brain circuit is going to be strengthened.

01:19:52.520 | It's not sufficient to have one or the other,

01:19:54.820 | you need both, hence the name AND gate.

01:19:57.240 | And the amygdala is very good

01:19:58.640 | at establishing these AND gate contingencies.

01:20:01.480 | It's also a very generic brain structure

01:20:03.820 | in the sense that it doesn't really care

01:20:06.360 | what sorts of sensory events are involved

01:20:09.240 | provided they correlated in time

01:20:11.100 | with that increase in adrenaline and corticosterone.

01:20:14.140 | This has a wonderful side and a kind of dark side.

01:20:17.800 | The dark side is that PTSD and traumas of various kinds

01:20:22.800 | often involve a increase in adrenaline

01:20:27.060 | because whatever it was that caused the PTSD

01:20:29.900 | was indeed very stressful,

01:20:31.060 | caused these big increases in these chemicals,

01:20:33.140 | and because the amygdala is rather general

01:20:37.000 | in its functions, right?

01:20:37.840 | It's not tuned or designed in any kind of way

01:20:40.600 | to be specifically active in response

01:20:42.840 | to particular types of sensory events or perceptions.

01:20:47.060 | Well, then what it means is that we can start

01:20:49.260 | to become afraid of entire city blocks

01:20:53.060 | where one bad thing happened in a particular room

01:20:56.040 | of a particular building in a city block.

01:20:58.220 | We can become fearful of any place

01:21:01.140 | that contains a lot of people

01:21:02.520 | if something bad happened to us

01:21:04.260 | in a place that contained a lot of people.

01:21:06.440 | The amygdala is not so much of a splitter,

01:21:09.380 | as we say in science, we talk about lumpers and splitters.

01:21:11.820 | Lumpers are kind of generalizers, if that's even a word,

01:21:16.380 | and I think it is,

01:21:17.220 | someone will tell me one way or the other,

01:21:18.720 | and splitters are people that are ultra precise

01:21:23.200 | and specific and nuanced about every little detail.

01:21:26.480 | The amygdala is more of a lumper than a splitter

01:21:29.560 | when it comes to sensory events.

01:21:31.560 | Other areas of the brain only become active

01:21:33.660 | under very, very specific conditions

01:21:35.580 | and only those conditions.

01:21:36.780 | And similarly, epinephrine is just a molecule.

01:21:40.740 | It's just a chemical that's circulating

01:21:43.500 | in our brain and body.

01:21:44.560 | There's no epinephrine specifically for a cold shower

01:21:48.120 | that is distinct from the epinephrine

01:21:50.000 | associated with a bad event,

01:21:51.200 | which is distinct from the epinephrine

01:21:52.760 | associated with a really exciting event

01:21:54.340 | that makes you really alert.

01:21:55.340 | Epinephrine is just a molecule, it's generic.

01:21:57.680 | And so these systems have a lot of overlap,

01:21:59.780 | and that can explain in large part

01:22:02.340 | why when good things happen in particular locations

01:22:05.560 | and in the company of particular people,

01:22:08.280 | we often generalize to large categories

01:22:11.620 | of people, places, and things.

01:22:13.440 | And when negative things happen in particular circumstances,

01:22:16.140 | we often generalize about people, places, and things

01:22:19.080 | associated with that negative event.

01:22:20.880 | So now I'd like to talk about other tools

01:22:22.660 | that you can leverage that have been shown

01:22:24.480 | in quality peer-reviewed studies

01:22:26.000 | to enhance learning and memory.

01:22:28.040 | And perhaps one of the most potent of those tools

01:22:30.720 | is exercise.

01:22:32.360 | There are numerous studies on this in both animal models

01:22:36.600 | and fortunately now also in humans,

01:22:39.400 | thanks to the beautiful work of people like Wendy Suzuki

01:22:42.220 | from New York University.

01:22:43.740 | Wendy's lab has identified how exercise works

01:22:47.040 | to enhance learning and memory

01:22:48.600 | and other forms of cognition, I should mention,

01:22:51.240 | as well as things that can augment,

01:22:54.480 | can enhance the effects of exercise on learning and memory

01:22:57.800 | and other forms of cognition.

01:22:59.840 | Wendy is going to be a guest on this podcast.

01:23:01.800 | It's actually the episode that follows this episode

01:23:05.000 | and includes a lot of material

01:23:06.320 | that we have not covered today.

01:23:08.120 | And she's an incredible scientist

01:23:10.720 | and has some incredible findings

01:23:12.600 | that I know everyone is going to find immensely useful.

01:23:15.540 | In the meantime,

01:23:16.920 | I want to talk about some of the general effects of exercise

01:23:19.900 | on learning and memory that she's discovered

01:23:22.000 | and the other laboratories have discovered.

01:23:24.260 | If you recall earlier,

01:23:25.140 | I mentioned that learning and memory

01:23:27.880 | almost always involves the strengthening

01:23:30.400 | of particular synapses and neural circuits in the brain

01:23:33.960 | and not so much the increase

01:23:36.580 | in the number of neurons in the brain.

01:23:39.160 | There is one exception, however,

01:23:40.960 | and we now have both animal data and some human data

01:23:43.640 | to support the fact that cardiovascular exercise

01:23:46.500 | seems to increase what we call dentate gyrus neurogenesis.

01:23:51.200 | Neurogenesis is the creation of new neurons.

01:23:53.440 | The dentate gyrus is a sub-region of the hippocampus

01:23:56.200 | that's involved in learning and memory of particular kinds,

01:23:59.800 | certain types of events, in particular contextual learning,

01:24:02.920 | but some other things as well,

01:24:04.860 | sometimes involved in spatial learning.

01:24:06.680 | There's a lot of debate about exactly

01:24:08.120 | what the dentate gyrus does,

01:24:09.480 | but for sake of this discussion,

01:24:11.340 | and I think everyone in the neuroscience community

01:24:14.580 | would agree that the dentate gyrus is important

01:24:16.620 | for memory formation and consolidation.

01:24:19.000 | The dentate gyrus does seem to be one region of the brain,

01:24:24.260 | certainly in the rodent brain,

01:24:25.540 | but more and more it's seeming also in the human brain

01:24:29.100 | where at least some new neurons

01:24:31.280 | are added throughout the lifespan.

01:24:33.180 | And as it turns out that cardiovascular exercise

01:24:36.720 | can increase the proliferation of new neurons

01:24:40.180 | in the structure and that those new neurons, excuse me,

01:24:44.040 | are important for the formation

01:24:46.560 | of certain types of new memories.

01:24:48.600 | There are wonderful data showing

01:24:49.960 | that if you use X irradiation,

01:24:52.100 | which is a way to eliminate the formation of those new cells

01:24:55.200 | or other tools and tricks

01:24:57.240 | to eliminate the formation of those cells,

01:24:59.160 | that you block the formation

01:25:00.960 | of certain kinds of learning and memory.

01:25:02.480 | What does this mean?

01:25:03.320 | Well, there are a lot of reasons

01:25:05.120 | for the statement I'm about to make

01:25:06.400 | that extend far beyond neurogenesis

01:25:09.280 | and the hippocampus learning and memory,

01:25:11.000 | but it's very clear that getting anywhere from 180,

01:25:14.700 | I should say a minimum of 180 to 200 minutes

01:25:17.760 | of so-called zone two cardiovascular exercise.

01:25:20.040 | So this is cardiovascular exercise that can be performed

01:25:23.320 | at a pretty steady state,

01:25:25.480 | which would allow you to just barely hold a conversation.

01:25:28.080 | So breathing hard, but not super hard.

01:25:31.000 | This isn't sprints or high intensity interval training,

01:25:33.320 | but doing that for 180 to 200 minutes per week total is,

01:25:37.940 | it appears the minimum threshold

01:25:39.640 | for enhancing some of the longevity effects

01:25:43.160 | associated with improvements in cardiovascular fitness.

01:25:46.280 | And we believe that it is indirectly,

01:25:48.960 | I should say indirectly through enhancements

01:25:51.280 | in cardiovascular fitness,

01:25:53.000 | that there are improvements

01:25:54.160 | in hippocampal dentate gyrus neurogenesis.

01:25:56.920 | What does that mean?

01:25:57.960 | The improvements in cardiovascular function

01:26:00.560 | are indirectly impacting the ability

01:26:02.700 | of the dentate gyrus to create these new neurons.

01:26:05.160 | To my knowledge, there's no direct relationship

01:26:07.920 | between exercise and stimulating the production

01:26:11.600 | of new neurons in the brain.

01:26:13.000 | It seems that it's the improvements in blood flow

01:26:17.260 | that also relate to improvements

01:26:18.920 | in things like lymphatic flow,

01:26:20.460 | the circulation of lymph fluid within the brain

01:26:22.840 | that are enhancing neurogenesis

01:26:24.900 | and that neurogenesis, it appears is important.

01:26:27.840 | Now, in fairness to the landscape of neuroscience

01:26:31.060 | and my colleagues at Stanford and elsewhere,

01:26:34.040 | there is a lot of debate as to whether or not

01:26:36.320 | there is much, if any, neurogenesis

01:26:39.640 | in the adult human brain.

01:26:42.100 | But regardless, I think the data are quite clear

01:26:44.760 | that the 180 to 200 minutes minimum

01:26:48.200 | of cardiovascular exercise is going to be important

01:26:50.960 | for other health metrics.

01:26:52.560 | Now, it is clear that exercise can impact learning

01:26:55.520 | and memory through other non-neurogenesis,

01:26:58.160 | non new neuron type mechanisms.

01:27:00.300 | And one of the more exciting ones

01:27:02.000 | that has been studied over the years

01:27:05.040 | is this notion of hormones from bone

01:27:08.680 | traveling in the bloodstream to the brain

01:27:11.000 | and enhancing the function of the hippocampus.

01:27:13.400 | Now, the words hormones from bones is surprising to you.

01:27:17.520 | I'm here to tell you that yes, indeed,

01:27:19.560 | your bones make hormones.

01:27:22.160 | We call these endocrine effects.

01:27:23.980 | So in biology, we hear about autocrine,

01:27:27.640 | paracrine and endocrine.

01:27:28.920 | And those different terms refer to over what distance

01:27:32.740 | a given chemical has an effect on a cell.

01:27:35.620 | For instance, a cell can have an effect on itself.

01:27:38.120 | It can have an effect on immediately neighboring cells,

01:27:40.600 | or it can have an effect on both itself,

01:27:43.420 | immediately neighboring cells,

01:27:44.600 | and cells far, far away in the body.

01:27:46.440 | And that last example of a given chemical or substance

01:27:50.840 | having an effect on the cell that produced it

01:27:54.220 | plus neighboring cells plus cells far away

01:27:56.380 | is an endocrine effect.

01:27:57.520 | And a lot of hormones not all work in this fashion.

01:28:01.360 | Hence, why we sometimes hear about endocrine and hormone

01:28:04.620 | is kind of synonymous terms.

01:28:06.000 | Your bones make chemicals that travel in the bloodstream

01:28:10.900 | and have these endocrine effects.

01:28:12.320 | So they're effectively acting as hormones.

01:28:14.000 | And one such chemical is something called osteocalcin.

01:28:17.260 | Now, these findings arrive to us through various labs,

01:28:19.560 | but one of the more important labs

01:28:20.860 | for sake of this discussion today

01:28:22.680 | is the laboratory of Eric Kandel

01:28:24.440 | at Columbia Medical School.

01:28:26.440 | Eric is now, I believe, in his mid to late 90s,

01:28:29.160 | still very sharp, and has studied learning and memory.

01:28:32.160 | It also turns out that he is an avid swimmer.

01:28:34.840 | Now, I happen to know that Eric swims

01:28:37.240 | anywhere from a half a mile to a mile a day.

01:28:39.960 | And again, this is anecdotal.

01:28:42.860 | I'm not referring to the published data just yet,

01:28:44.720 | but he credits that exercise as one of the ways

01:28:48.280 | in which he keeps his brain sharp

01:28:50.100 | and has indeed kept his brain sharp for many, many decades.

01:28:54.180 | And as I mentioned before, he's well into his 90s,

01:28:55.960 | so pretty impressive.

01:28:57.360 | His laboratory has studied the effects of exercise

01:29:00.640 | on hippocampal function and memory,

01:29:02.760 | and other laboratories have done that as well.

01:29:05.240 | And what they found is that cardiovascular exercise,

01:29:08.440 | and perhaps other forms of exercise too,

01:29:10.200 | but mainly cardiovascular exercise,

01:29:12.740 | creates the release of osteocalcin

01:29:15.040 | from the bones that travels to the brain

01:29:17.560 | and to subregions of the hippocampus

01:29:19.880 | and encourages the electrical activity

01:29:22.920 | and the formation and maintenance of connections

01:29:25.740 | within the hippocampus and keeps the hippocampus

01:29:28.540 | functioning well in order to lay down new memories.

01:29:31.440 | Now, osteocalcin has a lot of effects

01:29:33.480 | besides just improving the function of the hippocampus.

01:29:36.320 | Osteocalcin is involved in bone growth itself.

01:29:39.360 | It's involved in hormone regulation.

01:29:41.240 | In fact, there's really nice evidence

01:29:42.920 | that it can regulate testosterone and estrogen production

01:29:45.980 | by the testes and ovaries,

01:29:47.480 | and a bunch of other effects in other organs of the body,

01:29:49.880 | because again, it's acting in this endocrine manner.

01:29:52.120 | It's arriving from bone to a lot of different organs

01:29:55.500 | to have effects.

01:29:56.400 | Load-bearing exercise in particular

01:29:59.840 | turns out to be important

01:30:01.640 | for inducing the release of osteocalcin.

01:30:03.620 | And when you think about this, it makes sense.

01:30:06.800 | A nervous system exists for a lot of reasons,

01:30:08.940 | to sense, perceive, et cetera.

01:30:10.240 | You've got taste, you've got smell, you've got hearing.

01:30:12.160 | But the vast majority of brain real estate,

01:30:15.080 | especially in humans, is dedicated to two things.

01:30:18.080 | One, vision.

01:30:19.840 | We have an enormous amount of brain real estate

01:30:21.720 | devoted to vision, certainly compared to other senses.

01:30:25.560 | And to movement,

01:30:27.020 | the ability to generate coarse movements of the body,

01:30:29.540 | the ability, excuse me, to generate fine movements

01:30:32.500 | of the body, like the digits, or to wink one eye,

01:30:34.580 | or to tilt your head in a particular way,

01:30:36.440 | or move your lips, or move your face,

01:30:37.860 | and do all sorts of different things

01:30:39.060 | in a very nuanced and detailed way.

01:30:42.080 | So much of our brain real estate is devoted to movement,

01:30:45.100 | that it's been hypothesized for more than a half century,

01:30:49.420 | but especially in recent years,

01:30:51.120 | as we've learned more about the function of the brain

01:30:52.920 | at a really detailed circuit level,

01:30:54.840 | that the relationship between the brain and body

01:30:58.040 | and the maintenance,

01:31:00.200 | and perhaps even the improvement of neural circuitry

01:31:02.360 | in the brain, depends on our body movements

01:31:04.920 | and the signal from the body that our brain is still moving.

01:31:08.460 | So think about that.

01:31:09.300 | How would your brain know if your body was moving regularly?

01:31:11.900 | And how would it know how much it was moving?

01:31:13.580 | How would it know which limbs it was moving?

01:31:15.940 | Well, you could say, if the heart rate is increased,

01:31:18.660 | then the blood flow will be increased,

01:31:20.200 | and then the brain will know.

01:31:21.940 | Ah, but how does your brain know

01:31:24.600 | that it's increased blood flow due to movement

01:31:27.260 | and not to, for instance, just stress, right?

01:31:29.980 | Maybe you actually can't move

01:31:31.080 | and you're very stressed about that,

01:31:32.300 | and so the increased blood flow

01:31:33.800 | is simply a consequence of increased stress.

01:31:37.280 | The fact that osteocalcin is released from bone,

01:31:42.880 | and in particular can be released

01:31:44.720 | in response to load-bearing exercise,

01:31:46.900 | so this would be running.

01:31:48.400 | Again, weightlifting hasn't been tested directly,

01:31:50.480 | but one would imagine anything that involves

01:31:52.600 | jumping and landing or weightlifting or body weight movements

01:31:57.380 | and things of that sort,

01:31:59.320 | that's a signal to release osteocalcin,

01:32:01.840 | and we know that signal occurs,

01:32:03.960 | that is directly reflective of the fact

01:32:08.480 | that the body was moving and moving in particular ways.

01:32:11.200 | In fact, you could imagine that big bones, like your femur,

01:32:14.600 | are going to release more osteocalcin

01:32:16.240 | or be in a position to release more osteocalcin

01:32:18.280 | than fine movements like the movements of the digits.

01:32:21.240 | And this idea that the body is constantly signaling

01:32:24.480 | to the brain about the status of the body

01:32:26.720 | and the varying needs of the brain

01:32:29.100 | to update its brain circuitry

01:32:31.360 | is a really attractive idea that fits entirely

01:32:34.840 | with the biology of exercise,

01:32:36.840 | osteocalcin, and hippocampal function.

01:32:39.520 | I do want to mention that I'm not the first

01:32:42.440 | to raise this hypothesis.

01:32:43.760 | This hypothesis actually was discussed

01:32:45.660 | in a fair amount of detail by John Rady,

01:32:48.060 | who's a professor in Harvard Medical School.

01:32:50.300 | He wrote a book called "Spark,"

01:32:51.700 | which was one of the early books,

01:32:54.240 | at least from an academic, about brain plasticity

01:32:56.160 | and the relationship between exercise

01:32:57.640 | and movement in plasticity.

01:32:58.960 | And John, who I have the good fortune to know,

01:33:01.940 | has described to me experiments,

01:33:03.860 | or I should say observations,

01:33:05.480 | of species of ocean-dwelling animals

01:33:08.620 | that have, at least for the early part of their life,

01:33:11.040 | a very robust and complicated nervous system.

01:33:14.160 | But then these particular animals

01:33:16.640 | are in the habit of plopping down onto a rock.

01:33:19.380 | They find a kind of a safe, comfy space,

01:33:21.720 | and they actually stick to that rock,

01:33:24.000 | and they don't move anymore for a certain portion,

01:33:26.960 | I should say the late portion of their life.

01:33:29.100 | And it is at the transition between moving a lot

01:33:31.620 | and being stationary that those animals

01:33:33.540 | actually digest their own brain.

01:33:36.460 | They literally metabolize a good portion

01:33:38.920 | of their nervous system because they decide,

01:33:40.760 | oh, don't need this anymore, and gobble it up,

01:33:43.580 | use it for its nutritional value,

01:33:46.300 | and then sit there like a moron version of themselves

01:33:49.780 | with a limited amount of brain tissue

01:33:53.860 | because they don't need to move anymore.

01:33:55.420 | Now, I certainly don't want to give the message

01:33:57.120 | that just moving, just exercise is sufficient

01:34:00.060 | to keep the neural architecture of your brain

01:34:02.000 | healthy, young, and able to learn.

01:34:03.660 | While that might be true,

01:34:06.380 | it's also important to actually engage

01:34:08.180 | in attempts to learn new material,

01:34:10.220 | either physical material,

01:34:11.600 | so new types of movements and skills,

01:34:14.600 | and/or new types of cognitive information,

01:34:16.980 | languages, mathematics, history, current events,

01:34:20.840 | all sorts of things that involve your brain.

01:34:23.720 | Nonetheless, it's clear that physical movement

01:34:26.780 | and cognitive ability

01:34:28.560 | and the potential to enhance cognitive ability

01:34:31.360 | and the ability to learn new physical skills

01:34:33.280 | are intimately connected.

01:34:34.960 | And osteocalcin appears to be at least one way

01:34:38.400 | in which that brain-body relationship

01:34:40.040 | is established and maintained.

01:34:41.680 | So given the information about osteocalcin and movement,

01:34:45.120 | and given the information about spiking adrenaline late

01:34:48.960 | or after a period of attempt to learn,

01:34:52.300 | you might be asking, when is the best time to exercise?

01:34:55.120 | Now, unfortunately, that has not been addressed

01:34:58.020 | in a lot of varying detail

01:34:59.800 | where every sort of variation on the theme

01:35:02.720 | has been carried out.

01:35:03.680 | And yet, Wendy Suzuki's lab

01:35:05.400 | has done really beautiful experiments

01:35:07.720 | where they have people exercise,

01:35:10.200 | generally it was in the morning,

01:35:11.860 | but at other periods of the day as well.

01:35:14.640 | And what they find is that at least as late as two hours

01:35:18.600 | after that exercise,

01:35:20.680 | there's an enhancement in learning and memory.

01:35:23.240 | Now, I want to be clear,

01:35:24.440 | we don't know whether or not that exercise

01:35:26.760 | led to big increases in adrenaline.

01:35:29.600 | It may be that those forms of exercise were modest enough

01:35:33.600 | or didn't challenge people enough,

01:35:35.500 | that they merely got a lot of blood flow going,

01:35:37.600 | and that the improvements in learning and memory

01:35:39.220 | were related to blood flow,

01:35:40.380 | and we presume increases in osteocalcin.

01:35:43.920 | However, you could imagine

01:35:45.280 | a couple of different logical protocols

01:35:48.100 | based on what we've talked about.

01:35:50.060 | Let's say you were going to do a form of exercise

01:35:51.880 | that was going to spike adrenaline a lot.

01:35:53.560 | So this would be exercise that really challenges

01:35:56.420 | your system and forces you to kind of push through a burn.

01:35:59.160 | So here I'm mainly thinking about cardiovascular exercise,

01:36:01.960 | but it could even be yoga, it could be resistance training.

01:36:07.200 | If it's going to give you a big spike in adrenaline,

01:36:09.840 | it's going to take some serious effort,

01:36:12.380 | then logically speaking,

01:36:15.080 | you would want to place that after a learning bout

01:36:17.460 | in order to increase learning and memory.

01:36:19.180 | However, if you're using the exercise

01:36:21.740 | in order to enhance blood flow

01:36:23.480 | and to enhance osteocalcin release

01:36:26.120 | in efforts to augment the function of your hippocampus,

01:36:28.780 | I think it stands to reason that doing that exercise

01:36:31.760 | sometime within the hour to three hours

01:36:35.400 | preceding an attempt to learn

01:36:36.880 | makes a lot of sense.

01:36:37.880 | And there I'm basing it on the human data

01:36:39.480 | from Wendy Suzuki's lab,

01:36:41.080 | I'm basing it on the studies from Eric Kandel

01:36:43.340 | and from others labs.

01:36:45.320 | Again, right now there hasn't been an evaluation

01:36:48.040 | of a lot of different protocols to arrive

01:36:49.840 | at the peer reviewed laboratory super protocol.

01:36:53.500 | However, since what we're talking about

01:36:55.640 | is using activities like exercise

01:36:57.520 | that most of us probably, perhaps all of us

01:37:00.520 | should be doing regularly anyway.

01:37:02.520 | And I do believe most, if not all of us

01:37:04.640 | should probably regularly be trying to learn

01:37:06.440 | and keep our brain functioning well

01:37:08.080 | and acquire new knowledge

01:37:09.040 | because it's just a wonderful part of life.

01:37:10.740 | And there is evidence that that actually

01:37:12.160 | can keep your brain young, so to speak.

01:37:14.600 | Well then exercising either before or after a learning bout

01:37:19.600 | makes a lot of sense with the emphasis

01:37:22.660 | on after a learning bout,

01:37:24.180 | if the form of exercise spikes a lot of adrenaline

01:37:26.480 | for all the reasons we talked about before.

01:37:28.440 | Okay, so we've talked about two major categories

01:37:30.620 | of protocols to improve memory

01:37:32.200 | that are grounded in quality peer reviewed science.

01:37:35.240 | And there is yet another third protocol

01:37:37.760 | that we'll talk about in a few minutes.

01:37:39.440 | But before we do that,

01:37:40.760 | I want to briefly touch on an aspect of memory.

01:37:43.320 | In fact, two aspects of memory

01:37:44.760 | that I get a lot of questions about.

01:37:46.960 | The first one is photographic memory.

01:37:50.800 | To be clear, there are people out there

01:37:52.920 | who have a true photographic memory.

01:37:54.760 | They can look at a page of text,

01:37:56.600 | they can scan it with their eyes

01:37:57.840 | and they can essentially commit that to memory

01:38:00.760 | with very little, if any effort.

01:38:03.200 | While it might seem that having a photographic memory

01:38:04.920 | is a very attractive skill to have,

01:38:06.840 | I should caution you against believing that

01:38:09.040 | because it turns out that people

01:38:10.700 | with true photographic memory are often very challenged

01:38:13.260 | at remembering things that they hear

01:38:15.560 | and oftentimes are not so good at learning physical skills.

01:38:18.800 | It's not always the case, but often that's the case.

01:38:21.000 | So be careful what you wish for.

01:38:22.700 | If you do have a photographic memory,

01:38:24.400 | there are certain professions

01:38:25.580 | that lend themselves particularly well to you.

01:38:29.640 | And indeed, a lot of people with photographic memory

01:38:31.760 | have to find a profession and have to move through life

01:38:34.940 | in a way that is in concert with that photographic memory.

01:38:38.840 | So again, it's a super ability, it's a hyper ability,

01:38:42.280 | and yet it's not necessarily one

01:38:43.920 | that is desirable for most people.

01:38:46.360 | There's also this category

01:38:47.360 | of what are called super recognizers.

01:38:49.440 | These people are, I should mention,

01:38:51.020 | highly employable by government agencies.

01:38:53.320 | These are people that have an absolutely astonishing ability

01:38:57.820 | to recognize faces and to match faces,

01:39:01.400 | to templates.

01:39:02.240 | They can look at a photograph of, say,

01:39:04.640 | somebody on a most wanted list,

01:39:07.360 | and then they can look at video footage of,

01:39:11.160 | let's say, an airport or a mall or a city street

01:39:13.360 | at fairly low resolution,

01:39:15.260 | and they can spot the person whose face matches

01:39:18.420 | that photograph that they looked at.

01:39:20.360 | Even if that video or other footage is of people's profiles

01:39:25.360 | or even the tops of their heads

01:39:28.200 | and just a portion of their forehead,

01:39:29.380 | these people have just an incredible ability

01:39:32.140 | to recognize faces and to template match.

01:39:34.440 | And again, these people often will take jobs with agencies

01:39:37.560 | where this sort of thing is important.

01:39:39.760 | Some of you out there probably are super recognizers

01:39:42.560 | and may or may not notice it.

01:39:44.140 | If you've ever had the experience of watching a movie

01:39:46.180 | and thought to yourself,

01:39:47.620 | wow, her mouth looks so much like my cousin's mouth,

01:39:52.380 | or you look at a character in a movie or television show

01:39:56.340 | and you think, wow, they look almost like

01:39:59.240 | the younger sister of so-and-so,

01:40:01.680 | well, then it's very likely that you have this,

01:40:05.920 | or at least a mild form of this super recognizer ability.

01:40:09.080 | That is not memory per se.

01:40:11.640 | That is the hyperfunctioning of an area of the brain

01:40:14.320 | that we call the fusiform gyrus.

01:40:16.960 | The fusiform gyrus is literally a face recognition area

01:40:20.840 | and a face template matching area,

01:40:22.880 | and it harbors neurons that respond to faces generally.

01:40:25.840 | So as humans and other non-human primates

01:40:29.040 | care a lot about faces and their emotional content,

01:40:31.700 | and the identity of faces is super important to us

01:40:35.020 | for all the kinds of reasons that are probably obvious,

01:40:38.200 | knowing who's friend, who's foe, who do you know well,

01:40:40.900 | who's famous, who's not famous, et cetera.

01:40:43.840 | That is not memory per se.

01:40:45.700 | And yet if you're a super recognizer,

01:40:48.100 | or I guess we could call it a moderate face recognizer,

01:40:51.900 | or not very good at recognizing faces,

01:40:54.080 | 'cause indeed there are some people

01:40:55.200 | that are kind of face blind.

01:40:56.900 | They don't actually recognize people.

01:40:59.040 | When they walk in the room,

01:40:59.880 | I used to work with somebody like this,

01:41:01.040 | I'd walk into his office and he'd say,

01:41:02.660 | "Are you rich or are you Andrew?"

01:41:04.960 | I'd say, "Well, am I rich rich?

01:41:07.040 | Like, you know, wealth rich?"

01:41:08.220 | No.

01:41:09.060 | And he'd say, "No, are you Richard or are you Andrew?"

01:41:11.560 | And I'd say, "I'm Andrew.

01:41:12.720 | We know each other really well."

01:41:13.680 | He said, "Oh, I'm sorry, I'm kind of face blind."

01:41:16.080 | And it actually tend to be better or worse

01:41:18.920 | depending on how much he was working.

01:41:21.200 | Ironically, the more rested he was,

01:41:24.080 | the more face blind he would become.

01:41:25.520 | So it wasn't a sleep deprivation thing.

01:41:27.160 | That exists, that's out there.

01:41:28.280 | There's the full constellation

01:41:30.200 | of people's ability to recognize faces.

01:41:32.240 | That's not really memory.

01:41:33.380 | And yet visual function is a profoundly powerful way

01:41:37.680 | in which we can enhance our memory.

01:41:39.140 | So whether or not you're a super recognizer of faces,

01:41:41.800 | whether or not you are face blind or anything in between,

01:41:45.160 | next I'm going to tell you about a study

01:41:47.400 | which points out the immense value of visual images

01:41:52.120 | for laying down memories.

01:41:54.120 | And you can leverage this information

01:41:56.120 | and this involves both the taking a photograph,

01:41:58.280 | something that's actually quite easy,

01:41:59.760 | easily done these days with your phone,

01:42:01.560 | as well as your ability to take mental photographs

01:42:04.240 | by literally snapping your eyelid shut.

01:42:06.700 | So I just briefly want to describe this paper

01:42:08.440 | because it provides a tool that you can leverage

01:42:10.760 | in your attempt to learn and remember things better.

01:42:14.120 | The title of this paper is "Photographic Memory,

01:42:16.980 | the effects of our volitional photo taking

01:42:19.120 | on memory for visual and auditory aspects of an experience."

01:42:23.680 | I really like this paper

01:42:24.780 | because it refers to photographic memory,

01:42:27.680 | not in the context of photographic memory

01:42:30.160 | that we normally hear about

01:42:31.120 | where people are truly photographic,

01:42:32.760 | look at a page and somehow absorb all that information

01:42:35.600 | and commit it to memory,

01:42:36.680 | but rather the use of camera photographs

01:42:39.600 | or the use of mental camera photographs,

01:42:42.840 | literally looking at something and deciding blink

01:42:45.400 | and snapping a, so to speak, snapping a snapshot

01:42:49.380 | of whatever it is that you were looking at

01:42:50.880 | and remembering the content.

01:42:52.440 | The reason I like this paper

01:42:53.640 | and the reason I'm attracted to this issue

01:42:55.520 | of mental snapshots is this is something

01:42:57.200 | that I've been doing since I was a kid.

01:42:58.360 | I don't know why I started doing it,

01:42:59.640 | but every once in a while, I would say maybe twice a year,

01:43:03.420 | I would look at something

01:43:04.480 | and decide to just snap a mental snapshot of it.

01:43:07.440 | And I've maintained very clear memories

01:43:09.120 | of those visual scenes.

01:43:10.560 | Two years ago, I was in an Uber and I looked out the window

01:43:14.800 | and it was a street scene.

01:43:15.640 | I was actually in New York at the time

01:43:17.360 | and I decided for reasons that are still unclear to me

01:43:21.120 | to take a mental snapshot of this city street image,

01:43:23.400 | even though nothing interesting in particular was happening.

01:43:26.320 | And I do recall that there was a guy wearing a yellow shirt,

01:43:29.800 | walking, there was some construction, et cetera.

01:43:31.440 | I can still see that image in my mind's eye

01:43:33.720 | because I took this mental snapshot.

01:43:35.560 | This paper addresses

01:43:36.440 | whether or not this mental snapshotting thing is real.

01:43:38.780 | And this is something that I think a lot of people

01:43:42.040 | will resonate with,

01:43:43.000 | whether or not the constant taking of pictures on our phones

01:43:45.840 | or with other devices is either improving

01:43:48.560 | or degrading our memory.

01:43:50.140 | You can imagine an argument for both.

01:43:52.560 | A lot of people are taking pictures

01:43:53.820 | that they never look at again.

01:43:55.680 | And so in a sense,

01:43:56.520 | they're outsourcing their visual memory of events

01:44:00.480 | into their phone or to some other device.

01:44:03.440 | And they're not ever accessing the actual image again,

01:44:06.160 | they're not looking at it, right?

01:44:07.280 | You're not printing out those photos,

01:44:08.640 | you're not scanning through your phone again.

01:44:10.060 | Sometimes you might do that,

01:44:10.980 | but most of the time people don't.

01:44:12.060 | Most of the photographs that people take in,

01:44:13.520 | they're not revisiting again.

01:44:15.000 | So the motivation for this study was that

01:44:16.780 | previous experiments had shown that

01:44:19.720 | if people take photos of a scene or a person or an object,

01:44:24.440 | that they are actually less good at remembering

01:44:27.700 | the details of that scene or object, et cetera.

01:44:31.220 | This study challenged that idea and raised the hypothesis

01:44:36.300 | that if people are allowed to choose

01:44:39.000 | what they take photos of,

01:44:40.720 | that taking photos, again,

01:44:42.400 | this is with a camera, not mental snapshotting,

01:44:44.220 | that taking those photos would actually enhance their memory

01:44:47.020 | for those objects, those places, those people,

01:44:49.680 | and in fact, details of those object places and people.

01:44:53.080 | And indeed that's what they found.

01:44:54.920 | So in contrast to previous studies,

01:44:56.940 | where people had been more or less told,

01:44:59.520 | take photos of these following objects

01:45:01.380 | or these following people or these following places,

01:45:03.680 | and then they were given a memory test at some point later.

01:45:07.480 | In this study, people were given volitional control, right?

01:45:11.280 | They were given agency in making the decision

01:45:13.700 | of what to take photos of.

01:45:15.000 | And I'll just summarize the results.

01:45:16.240 | We'll provide a link to this study.

01:45:17.480 | I should say that some of the stuff that they tested

01:45:19.900 | was actually pretty challenging.

01:45:21.520 | Some of them were pottery and other forms of ceramics

01:45:24.960 | that are of the sort that you see

01:45:26.600 | if you go to a big museum in a big city,

01:45:28.560 | and if you've ever done that

01:45:29.480 | and you see all the different objects,

01:45:31.120 | there are a lot of details in those objects,

01:45:32.600 | and a lot of those objects look a lot alike.

01:45:35.300 | And so, you know, some will have two handles,

01:45:37.700 | some will have one handle, the position of the handles,

01:45:39.660 | how broad or narrow these things are.

01:45:42.500 | You know, a lot of this is pretty detailed stuff.

01:45:44.460 | They also took photos of other things.

01:45:47.300 | So basically what they found

01:45:48.820 | was that if people take pictures of things

01:45:50.860 | and they choose which things they're taking pictures of,

01:45:53.460 | right, it's up to them, it's volitional,

01:45:55.240 | that there's enhanced memory for those objects later on.

01:46:00.240 | However, it degraded their ability

01:46:04.380 | to remember auditory information.

01:46:06.180 | So what this means is that

01:46:07.020 | when we take a picture of something or a person,

01:46:11.060 | we are stamping down a visual memory of that thing,

01:46:14.620 | and that makes sense, it's a photograph after all,

01:46:16.840 | but we are actually inhibiting our ability

01:46:19.060 | to remember the auditory, the sound components

01:46:22.460 | of that visual scene or what the person was saying.

01:46:24.560 | Very interesting, and points to the fact

01:46:26.460 | that the visual system can out-compete the auditory system,

01:46:29.140 | at least in terms of how the hippocampus

01:46:30.980 | is encoding this information.

01:46:32.740 | The other finding I find particularly interesting

01:46:34.720 | within this study is that it didn't matter

01:46:38.420 | whether or not they ever looked at the photos again.

01:46:40.520 | So they actually had people take photos

01:46:42.940 | or not take photos of different objects.

01:46:45.600 | They had some people keep their photos

01:46:47.660 | and they had other people delete their photos.

01:46:49.340 | And turns out that whether or not people kept the photos

01:46:52.260 | or deleted those photos had no bearing

01:46:53.980 | on whether or not they were better or worse

01:46:56.420 | at remembering things, they were always better

01:46:58.020 | at remembering them as compared to not taking photos of them.

01:47:01.020 | What does this mean?

01:47:01.860 | It means if you really want to remember something

01:47:03.580 | or somebody, take a photo of that thing or person,

01:47:07.600 | pay attention while you take the photo,

01:47:10.100 | but it doesn't really matter if you look at the photo again.

01:47:12.020 | Somehow the process of taking that photo,

01:47:14.500 | probably looking at it in a camera,

01:47:18.340 | typically we'd say through the viewfinder now

01:47:20.240 | because of digital cameras on the screen

01:47:22.260 | on the back of that camera or on your phone,

01:47:25.180 | that framing up of the photograph

01:47:27.020 | stamps down a visual image in your mind

01:47:29.020 | that is more robust at serving a memory

01:47:32.020 | than had you just looked at that thing with your own eyes.

01:47:34.980 | Very interesting and it raises all sorts of questions for me

01:47:37.980 | about whether or not it's because you're framing up

01:47:39.980 | a small aperture or a small portion of the visual scene.

01:47:42.820 | That's one logical interpretation,

01:47:44.420 | although they didn't test that.

01:47:45.920 | I should also say that they found

01:47:47.700 | that whether or not you looked at a photo that you took

01:47:50.580 | or whether or not you deleted it

01:47:51.860 | and never looked at it again,

01:47:53.720 | didn't just enhance visual memory

01:47:55.740 | or the memory for the visual components of that image,

01:47:59.000 | but it always reduced your ability to remember

01:48:02.480 | sounds associated with that experience.

01:48:04.760 | So that's interesting.

01:48:06.300 | And then last but not least,

01:48:08.100 | and perhaps most interesting, at least to me,

01:48:10.380 | was the fact that you didn't even need a camera

01:48:12.820 | to see this effect.

01:48:14.540 | If subjects looked at something

01:48:16.500 | and took a mental photograph of that thing,

01:48:19.340 | it enhanced their visual memory of that thing

01:48:23.060 | significantly more than had they not taken a mental picture.

01:48:26.620 | In fact, it increased their memory of that thing

01:48:30.260 | almost as much as taking an actual photograph

01:48:32.760 | with an actual camera.

01:48:34.360 | And the reason I find this so interesting

01:48:36.340 | is that a lot of what we try and learn is visual.

01:48:40.500 | And for a lot of people,

01:48:41.900 | the ability to learn visual information feels challenging

01:48:45.900 | and we'll look at something

01:48:47.020 | and we'll try and create some detailed understanding of it.

01:48:49.860 | We'll try and understand the relationships

01:48:51.260 | between things in that scene.

01:48:53.380 | It does appear based on the study

01:48:54.940 | that the mere decision to take a mental snapshot,

01:48:58.380 | like, okay, I'm going to blink my eyelids

01:48:59.880 | and I'm going to take a snapshot of whatever it is I see,

01:49:01.700 | can actually stamp down a visual memory

01:49:04.220 | much in the same way

01:49:05.580 | that a camera can stamp down a visual memory,

01:49:07.760 | of course, through vastly distinct mechanisms.

01:49:10.680 | No discussion of memory would be complete

01:49:13.220 | without a discussion of the ever intriguing phenomenon

01:49:17.100 | known as deja vu.

01:49:19.260 | This sense that we've experienced something

01:49:21.220 | before but we can't quite put our finger on it.

01:49:23.500 | Where and when did it happen?

01:49:24.980 | Or the sense that we've been someplace before

01:49:27.260 | or that we are in a familiar state

01:49:30.220 | or place or context of some kind.

01:49:33.600 | Now, I've talked about this on the podcast before,

01:49:36.380 | at least I think I have,

01:49:37.860 | and the way this works has been defined

01:49:41.000 | largely by the wonderful work of Susumu Tonogawa

01:49:44.060 | at Massachusetts Institute of Technology, MIT.

01:49:47.340 | Susumu collected a Nobel Prize quite appropriately

01:49:50.660 | for his beautiful work on immunology

01:49:52.920 | and he's also a highly accomplished neuroscientist

01:49:55.620 | who studies memory and learning and deja vu.

01:49:58.860 | And I should also mention the beautiful work of Mark Mayford

01:50:01.860 | at the Scripps Institute in UC San Diego,

01:50:04.620 | beautiful work on this notion of deja vu.

01:50:06.660 | Here's what they discovered.

01:50:08.720 | They evaluated the patterns of neural firing

01:50:11.220 | in the hippocampus as subjects learn new things, okay?

01:50:16.220 | So neuron A fires, then neuron B fires,

01:50:20.020 | then neuron C fires in a particular sequence.

01:50:22.820 | Again, the firing of neurons in a particular sequence,

01:50:25.800 | like the playing of keys on a piano

01:50:27.500 | in a particular sequence

01:50:28.360 | leads to a particular song on the piano

01:50:30.020 | and leads to a particular memory

01:50:32.180 | of an experience within the brain.

01:50:34.020 | They then used some molecular tools and tricks

01:50:39.220 | to label and capture those neurons

01:50:41.940 | such that they could go back later

01:50:43.980 | and activate those neurons in either the same sequence

01:50:47.980 | or in a different sequence to the one that occurred

01:50:51.140 | during the formation of the memory.

01:50:53.660 | And to make a long story short

01:50:55.220 | and to summarize multiple papers

01:50:57.300 | published in incredibly high tier journals,

01:51:00.540 | journals like Nature and Science,

01:51:02.060 | which are extremely stringent,

01:51:03.800 | found that whether or not those particular neurons

01:51:08.800 | were played in the precise sequence

01:51:10.680 | that happened when they encoded the memory

01:51:13.380 | or whether or not those neurons were played

01:51:15.140 | in a different sequence

01:51:16.660 | or even if those neurons were played,

01:51:19.580 | activated that is, all at once with no temporal sequence,

01:51:24.580 | all firing in concert all at once,

01:51:27.540 | evoked the same behavior and in some sense, the same memory.

01:51:33.580 | So at a neural circuit level, this is deja vu.

01:51:38.940 | This is a different pattern of firing of neurons

01:51:41.820 | in the brain leading to the same sense of what happened

01:51:46.220 | leading to a particular emotional state or behavior.

01:51:51.120 | Now, whether or not this same sort of phenomenon occurs

01:51:54.180 | when you're walking down the street

01:51:55.420 | and suddenly you feel as if,

01:51:57.160 | wow, I feel like I've been here before.

01:51:58.580 | You meet someone and you feel like,

01:51:59.740 | gosh, I feel like I know you.

01:52:01.180 | I feel like there's some familiarity here

01:52:03.340 | that I can't quite put my finger on.

01:52:04.760 | We don't know for sure that that's what's happening,

01:52:07.660 | but this is the most mechanistic and logical explanation

01:52:11.820 | for what has for many decades, if not hundreds of years,

01:52:15.740 | has been described as deja vu.

01:52:17.660 | So for those of you that experienced deja vu often,

01:52:20.500 | just know that this reflects a normal pattern

01:52:23.660 | of encoding experiences and events within your hippocampus.

01:52:27.940 | I'm not aware of any pathological situations

01:52:30.820 | where the presence of deja vu inhibits daily life.

01:52:34.820 | Some people like the sensation of deja vu,

01:52:37.420 | other people don't.

01:52:38.620 | Almost everybody, however, describes it as somewhat eerie.

01:52:41.820 | This idea that even though you're in a very different place,

01:52:44.300 | even though you're interacting with a very different person,

01:52:46.900 | that you could somehow feel as if this has happened before.

01:52:50.980 | And just realize this, that your hippocampus,

01:52:53.760 | while it is exquisitely good at encoding

01:52:57.700 | new types of perceptions, new experiences, new emotions,

01:53:02.700 | new contingencies and relationships of life events,

01:53:07.180 | it is not infinitely large,

01:53:08.900 | nor does it have an infinite bucket

01:53:11.780 | full of different options of different sequences

01:53:14.220 | for those neurons to play.

01:53:15.540 | So in a lot of ways, it makes perfect sense

01:53:17.820 | that sometimes we would feel as if a given experience

01:53:20.620 | had happened previously.

01:53:22.100 | I'd like to cover one additional tool that you can use

01:53:24.820 | to improve learning and memory.

01:53:26.380 | And I should mention, this is a particularly powerful one,

01:53:29.500 | and it's one that I'm definitely going to employ myself.

01:53:33.420 | This is based on a paper from none other

01:53:36.860 | than Wendy Suzuki at New York University.

01:53:39.360 | We talked about her a little bit earlier.

01:53:40.980 | And again, she's going to be on the podcast

01:53:42.900 | in our next episode and is just an incredible researcher.

01:53:46.380 | I've known Wendy for a number of years,

01:53:47.820 | and it's only in the last, I would say five or six years,

01:53:50.200 | that she's really shifted her laboratory

01:53:52.340 | toward generating protocols that human beings can use.

01:53:56.100 | And she's putting that to great effect,

01:53:58.580 | great positive effect, I should say,

01:54:00.420 | publishing papers of the sort that I'm about to describe,

01:54:02.520 | but also incorporating some of these tools and protocols

01:54:05.480 | into the learning curriculum

01:54:07.260 | and the lifestyle curriculum of students at NYU,

01:54:10.380 | which I think is a terrific initiative.

01:54:12.540 | So you don't need to be an NYU student

01:54:14.020 | in order to benefit from her work.

01:54:15.620 | I'm going to tell you about some of that work now,

01:54:17.100 | and she'll tell you about this and much more

01:54:19.740 | in the episode that follows this one.

01:54:21.640 | The title of this paper will tell you a lot

01:54:23.980 | about where we're going.

01:54:24.920 | The title is "Brief Daily Meditation Enhances Attention,

01:54:28.740 | Memory, Mood, and Emotional Regulation

01:54:31.220 | in Non-Experienced Meditators."

01:54:33.900 | If ever there was an incentive to meditate,

01:54:36.040 | it is the data contained within this paper.

01:54:40.300 | I want to briefly describe the study,

01:54:41.860 | and then I also want to emphasize

01:54:44.420 | that when you meditate is absolutely critical.

01:54:47.500 | I'll talk about that just at the end.

01:54:49.540 | This is a study that involves subjects aged 18 to 45,

01:54:54.180 | none of whom were experienced meditators

01:54:56.380 | prior to this study.

01:54:57.500 | There were two general groups in this study.

01:55:01.460 | One group did a 13-minute long meditation,

01:55:06.800 | and this meditation was a fairly conventional meditation.

01:55:09.940 | They would sit or lie down.

01:55:11.840 | They would do somewhat of a body scan,

01:55:14.220 | evaluating, for instance,

01:55:15.460 | how tense or relaxed they felt throughout their body,

01:55:17.700 | and they would focus on their breathing,

01:55:19.560 | trying to bring their attention back to their breathing

01:55:21.480 | and to the state of their body as the meditation progressed.

01:55:25.200 | The other group, which we can call the control group,

01:55:28.740 | listened to, of all things, a podcast.

01:55:31.660 | They did not listen to this podcast.

01:55:33.480 | They listened to "Radio Lab," which is a popular podcast

01:55:36.620 | for an equivalent amount of time,

01:55:38.520 | but they were not instructed to do any kind of body scan

01:55:40.720 | or pay attention to their breathing.

01:55:43.300 | Every subject in the study either meditated daily

01:55:46.240 | or listened to a equivalent duration podcast daily

01:55:49.400 | for a period of eight weeks.

01:55:51.840 | And the experimenters measured a large number of things,

01:55:56.060 | of variables, as we say.

01:55:58.020 | They looked at measures of emotion regulation.

01:56:00.500 | They actually measured cortisol, a stress hormone.

01:56:02.980 | They measured, as the title suggests,

01:56:05.200 | attention and memory and so forth.

01:56:07.740 | And the basic takeaway of the study is that eight weeks,

01:56:12.260 | but not four weeks, of this daily 13-minute-a-day meditation

01:56:16.240 | had a significant effect in improving attention, memory,

01:56:21.240 | mood, and emotion regulation.

01:56:23.080 | I find this study to be very interesting

01:56:26.820 | and, in fact, important because most of us have heard

01:56:30.080 | about the positive effects of meditation

01:56:31.860 | on things like stress reduction

01:56:34.080 | or on things such as improving sleep.

01:56:36.700 | And I want to come back to sleep in a few moments

01:56:39.280 | 'cause it turns out to be a very important feature

01:56:41.100 | of this study.

01:56:41.940 | This particular study I like so much

01:56:45.660 | because they used a really broad array of measurements

01:56:49.880 | for cognitive function,

01:56:51.260 | things like the Wisconsin card sorting task.

01:56:53.260 | I'm not going to go into this.

01:56:54.220 | Things like the Stroop task.

01:56:55.600 | And they also, as I mentioned, measured cortisol

01:56:58.700 | and many other things, including, not surprisingly, memory.

01:57:03.260 | And people's ability to remember

01:57:05.620 | certain types of information,

01:57:06.740 | in fact, varied types of information.

01:57:08.800 | And the basic takeaway was, again,

01:57:11.740 | that you could get really robust improvements

01:57:14.180 | in learning and memory, mood, and attention

01:57:16.720 | from just 13 minutes a day of meditation.

01:57:19.620 | Now, there's an important twist in this study

01:57:21.380 | that I want to emphasize.

01:57:22.780 | If you read into the discussion of this study,

01:57:25.260 | it's mentioned that somehow meditation did not improve

01:57:30.100 | but actually impaired sleep quality

01:57:32.340 | compared to the control subjects.

01:57:34.240 | You might think, wow, why would that be?

01:57:36.080 | I mean, meditation is supposed to reduce our stress.

01:57:38.860 | Stress is supposed to inhibit sleep.

01:57:40.680 | And therefore, why would sleep get worse?

01:57:44.460 | Well, what's interesting is the time of day

01:57:47.040 | when most of these subjects tended to do their meditation.

01:57:51.200 | Most of the subjects in this study

01:57:52.680 | did their meditation late in the day.

01:57:54.400 | This is often the case in experiments.

01:57:56.060 | I know this because we run experiments

01:57:58.260 | with human subjects in my laboratory.

01:57:59.840 | And people are paid some amount of money

01:58:02.040 | in order to participate,

01:58:03.100 | or they're given something as compensation

01:58:05.400 | for being in the study.

01:58:06.240 | But oftentimes, the meditation, or in the case of my lab,

01:58:09.580 | the respiration work or other kinds of things

01:58:12.560 | that they're assigned to do are not their top, top priority.

01:58:15.500 | And we understand this.

01:58:16.580 | But in this study, the majority of subjects here I'm reading

01:58:19.020 | completed their meditation sessions

01:58:21.340 | from somewhere between 8 and 11 p.m.

01:58:24.460 | and sometimes even between 12 and 3 a.m.

01:58:27.660 | I think there probably were a lot of college students

01:58:29.280 | enrolled in this study.

01:58:30.460 | And their hours often are late shifted.

01:58:33.640 | That impaired sleep.

01:58:35.320 | And this raises a bigger theme that I think is important

01:58:37.740 | many times before on this podcast

01:58:39.700 | and certainly in the episode on mastering sleep

01:58:41.640 | and conquering or mastering stress.

01:58:44.580 | Those episodes, we talked about the value, again,

01:58:46.820 | of these non-sleep deep rest protocols, NSDR,

01:58:49.840 | for reducing the activity of your sympathetic nervous system,

01:58:53.980 | the alertness, so-called stress arm

01:58:56.420 | of your autonomic nervous system,

01:58:58.960 | that makes you feel really alert.

01:59:00.420 | NSDR is superb for reducing your level of alertness,

01:59:04.420 | increasing your level of calmness,

01:59:05.780 | and putting you into a so-called

01:59:06.720 | more parasympathetic relaxed state.

01:59:09.860 | Meditation does that too, but it also increases attention.

01:59:14.200 | If you think about meditation,

01:59:16.240 | meditation involves focusing on your breath

01:59:18.580 | and constantly focusing back on your breath

01:59:20.600 | and trying to avoid the distraction of things you're thinking

01:59:23.020 | or things that you're hearing

01:59:24.260 | and coming so-called back to your body, back to your breath.

01:59:28.000 | So meditation actually has a high attentional load.

01:59:33.000 | It requires a lot of prefrontal cortical activity

01:59:35.720 | that's involved in attention,

01:59:37.100 | which then logically relates

01:59:40.680 | to one of the outcomes of this study,

01:59:42.840 | which is that attention abilities

01:59:44.640 | improved in daily meditators.

01:59:46.840 | It also points out that increasing the level of attention

01:59:50.640 | and the activity of your prefrontal cortex may,

01:59:53.060 | and I want to emphasize may

01:59:53.980 | because here I'm speculating about the underlying mechanism,

01:59:56.540 | inhibit your ability to fall asleep.

01:59:59.060 | So while we have meditation on the one hand

02:00:01.140 | that does tend to put us into a calm state,

02:00:03.060 | but it is a calm, very focused state.

02:00:05.560 | In fact, attention and focus are inherent

02:00:08.140 | to most forms of meditation.

02:00:10.040 | Non-sleep deep rest, such as yoga nidra,

02:00:12.740 | as some of you know it to be, or NSDR.

02:00:16.060 | There's a terrific NSDR script that's available free online

02:00:19.220 | that's put out by Made For.

02:00:20.420 | So you can go to YouTube, NSDR Made For.

02:00:22.380 | You can also just do a search for NSDR.

02:00:25.100 | There are a number of these available out there,

02:00:26.900 | again, at no cost.

02:00:28.860 | Those NSDR protocols tend to put people

02:00:32.340 | into a state of deep relaxation,

02:00:34.620 | but also very low attention.

02:00:37.960 | And we have to assume very low activation

02:00:41.140 | of the prefrontal cortex.

02:00:42.660 | So the takeaways from the study are several fold.

02:00:44.600 | First of all, that daily meditation of 13 minutes

02:00:48.260 | can enhance your ability to pay attention and to learn.

02:00:51.300 | It can truly enhance memory.

02:00:54.400 | However, you need to do that for at least eight weeks

02:00:57.940 | in order to start to see the effects to occur.

02:01:00.660 | And we have to presume that you have to continue

02:01:02.900 | those meditation training sessions.

02:01:05.280 | In fact, they found that if people

02:01:08.340 | only did four weeks of meditation,

02:01:09.740 | these effects didn't show up.

02:01:11.020 | Now, eight weeks might seem like a long time,

02:01:13.020 | but I think that 13 minutes a day

02:01:14.620 | is not actually that big of a time commitment.

02:01:18.500 | And the results of this study certainly incentivize me

02:01:21.440 | to start adopting a, I'm going for 15 minutes a day now.

02:01:24.860 | I've been a on and off meditator for a number of years.

02:01:27.740 | I've been pretty good about it lately,

02:01:29.180 | but I confess I've been doing far shorter meditations

02:01:31.940 | of anywhere from three to five or maybe 10 minutes.

02:01:34.660 | I'm going to ramp that up to 15 minutes a day.

02:01:37.540 | And I'm doing that specifically to try

02:01:39.540 | and access these improvements in cognitive ability

02:01:42.260 | and our abilities to learn.

02:01:43.700 | Also based on the data in this paper,

02:01:45.740 | I'm going to do those meditation sessions

02:01:47.500 | either early in the day,

02:01:48.980 | such as immediately after waking or close to it.

02:01:52.960 | I might get my sunshine first.

02:01:54.820 | As you all know,

02:01:55.660 | very big on getting sunlight in the eyes early in the day

02:01:57.640 | as much as one can and as early as one can

02:02:00.200 | once the sun is out,

02:02:02.720 | but certainly doing it early in the day

02:02:04.920 | and not past 5 PM or so

02:02:07.640 | in order to make sure that I don't inhibit sleep.

02:02:09.920 | Because I think this result that they describe

02:02:11.940 | of meditation inhibiting quality sleep

02:02:14.880 | compared to controls is an important one

02:02:17.880 | to pay attention to, no pun intended.

02:02:20.180 | Today, we covered a lot of aspects of memory

02:02:22.560 | and how to improve your memory.

02:02:24.480 | We talked about the different forms of memory

02:02:26.260 | and we talked about some of the underlying neural circuitry

02:02:28.840 | of memory formation.

02:02:30.340 | And we talked about how the emotional saliency

02:02:34.020 | and intensity of what you're trying to learn

02:02:36.440 | has a profound impact on whether or not you learn

02:02:40.100 | in response to some sort of experience,

02:02:41.980 | whether or not that experience is reading

02:02:44.540 | or mathematics or music or language or a physical skill.

02:02:49.000 | It doesn't matter.

02:02:50.240 | The more intense of an emotional state that you're in

02:02:54.080 | in the period immediately following that learning,

02:02:57.040 | the more likely you are to remember

02:02:59.420 | whatever it is that you're trying to learn.

02:03:01.440 | And we talked about the neurochemicals

02:03:02.800 | that explain that effect,

02:03:04.560 | about epinephrine and corticosterones like cortisol

02:03:08.320 | and how adjusting the timing of those

02:03:10.580 | is so key to enhancing your memory.

02:03:13.280 | And we talked about the different ways

02:03:14.600 | to enhance those chemicals,

02:03:15.660 | everything ranging from cold water to pharmacology

02:03:19.200 | and even just adjusting the emotional state within your mind

02:03:22.420 | in order to stamp down and remember experiences better.

02:03:26.080 | We also talked about how to leverage exercise

02:03:28.140 | in particular load-bearing exercise

02:03:31.700 | in order to evoke the release of hormones like osteocalcin,

02:03:34.760 | which can travel from your bones to your brain

02:03:36.520 | and enhance your ability to learn.

02:03:38.520 | And we talked about a new form of photographic memory,

02:03:41.000 | not the traditional type of photographic memory

02:03:43.800 | in which people can remember

02:03:44.920 | everything they look at very easily,

02:03:47.160 | but rather taking mental snapshots of things that you see.

02:03:50.460 | Again, emphasizing that that will create a better memory

02:03:53.320 | of what you see when you take that mental snapshot,

02:03:55.560 | but will actually reduce your memory

02:03:57.600 | for the things that you hear at that moment.

02:03:59.660 | And we discussed the really exciting data

02:04:01.240 | looking at how particular meditation protocols

02:04:03.960 | can enhance memory, but also attention and mood.

02:04:07.660 | However, if done too late in the day,

02:04:10.740 | can actually disrupt sleep precisely

02:04:12.780 | because those meditation protocols can enhance attention.

02:04:17.340 | Now, I know that many of you are interested

02:04:18.800 | in neurochemicals that can enhance learning and memory,

02:04:22.380 | and I intend to cover those in deep detail

02:04:26.600 | in a future episode.

02:04:28.000 | However, for sake of what was discussed today,

02:04:30.240 | please understand that any number of different neurochemicals

02:04:34.320 | can evoke or can increase the amount of adrenaline

02:04:37.280 | that's circulating in your brain and body.

02:04:39.600 | And it's less important how one accesses

02:04:43.120 | that increase in adrenaline, right?

02:04:44.980 | Again, this can be done through behavioral protocols

02:04:46.900 | or through pharmacology.

02:04:48.240 | Assuming that those behavioral protocols

02:04:51.840 | and pharmacology are safe for you,

02:04:53.860 | it really doesn't matter how you evoke the adrenaline release

02:04:56.660 | because remember, adrenaline is the final common pathway

02:05:00.160 | by which particular experiences,

02:05:02.280 | particular perceptions are stamped into memory,

02:05:05.640 | which answers our very first question

02:05:07.960 | raised at the beginning of the episode,

02:05:09.300 | which is why do we remember anything at all, right?

02:05:12.380 | That was the question that we raised.

02:05:14.260 | Why is it that from morning till night

02:05:16.080 | and throughout your entire life,

02:05:17.380 | you have tons of sensory experience, tons of perceptions,

02:05:19.720 | why is it that some are remembered and others are not?

02:05:23.160 | While I would never want to distill an important question

02:05:26.740 | such as that down to a one-molecule type of answer,

02:05:29.840 | I think we can confidently say,

02:05:31.760 | based on the vast amount of animal and human research data,

02:05:36.140 | that epinephrine, adrenaline, and some of the other chemicals

02:05:39.900 | that it acts with in concert is in fact the way

02:05:44.380 | that we remember particular events and not all events.

02:05:49.020 | If you're learning from and/or enjoying this podcast,

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02:06:29.580 | During today's episode and on many previous episodes

02:06:31.940 | of the Huberman Lab Podcast, we discuss supplements.

02:06:34.880 | While supplements aren't necessary for everybody,

02:06:37.200 | many people derive tremendous benefit from them

02:06:39.320 | for things like enhancing sleep and focus

02:06:41.400 | and indeed for learning and memory.

02:06:43.480 | For that reason, the Huberman Lab Podcast

02:06:45.340 | is now partnered with Momentous Supplements.

02:06:47.760 | The reason we partnered with Momentous is several fold.

02:06:50.420 | First of all, we wanted to have one location

02:06:52.600 | where people could go to access single ingredient,

02:06:55.560 | high quality versions of the supplements

02:06:57.400 | that we were discussing on this podcast.

02:06:59.760 | This is a critical issue.

02:07:00.980 | A lot of supplement companies out there

02:07:02.580 | sell excellent supplements,

02:07:03.780 | but they combine different ingredients

02:07:05.720 | into different formulations,

02:07:07.080 | which make it very hard to figure out

02:07:08.640 | exactly what works for you

02:07:10.120 | and to arrive at the minimal effective dose

02:07:12.800 | of the various compounds that are best for you,

02:07:14.940 | which we think is extremely important.

02:07:16.800 | And that's certainly the most scientific way

02:07:18.760 | or rigorous way to approach

02:07:20.320 | any kind of supplementation regimen.

02:07:22.240 | So Momentous has made these single ingredient formulations

02:07:24.880 | on the basis of what we suggested to them.

02:07:27.260 | And I'm happy to say they also ship internationally.

02:07:30.040 | So whether or not you're in the US or abroad,

02:07:32.060 | they'll ship to you.

02:07:32.920 | If you'd like to see the supplements recommended

02:07:34.700 | on the Huberman Lab Podcast,

02:07:36.460 | you can go to livemomentous.com/huberman.

02:07:40.040 | They've started to assemble the supplements

02:07:42.000 | that we've talked about on the podcast.

02:07:43.500 | And in the upcoming weeks,

02:07:45.180 | they will be adding many more supplements

02:07:47.180 | such that in a brief period of time,

02:07:50.560 | most, if not all of the compounds

02:07:52.300 | that are discussed on this podcast

02:07:54.020 | will be there again in single ingredient,

02:07:56.620 | extremely high quality formulations

02:07:58.480 | that you can use to arrive

02:07:59.660 | at the best supplement protocols for you.

02:08:01.980 | We also include behavioral protocols

02:08:04.100 | that can be combined with supplementation protocols

02:08:06.520 | in order to deliver the maximum effect.

02:08:08.800 | Once again, that's livemomentous.com/huberman.

02:08:12.140 | And if you're not already following us

02:08:13.620 | on Twitter and Instagram,

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02:08:18.140 | There, I describe science and science-related tools,

02:08:21.220 | some of which overlap with the content

02:08:22.820 | of the Huberman Lab Podcast,

02:08:24.060 | but much of which is distinct

02:08:25.440 | from the content of the Huberman Lab Podcast.

02:08:27.780 | We also have a newsletter

02:08:29.180 | called the Huberman Lab Neural Network.

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02:08:33.880 | and information from our various podcast episodes.

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02:08:38.480 | You can go to HubermanLab.com,

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02:08:46.420 | We have a very clear privacy policy

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02:08:50.300 | And that newsletter comes out about once a month.

02:08:52.260 | You can also see some sample newsletters,

02:08:53.960 | things like the toolkit for sleep or for neuroplasticity

02:08:57.300 | and for various other topics

02:08:58.520 | covered on the Huberman Lab Podcast.

02:09:00.540 | Once again, thank you for joining me today

02:09:02.540 | to discuss the neurobiology of learning and memory

02:09:04.780 | and how to improve your memory using science-based tools.

02:09:08.580 | And last, but certainly not least,

02:09:10.620 | thank you for your interest in science.

02:09:12.480 | [upbeat music]

02:09:15.060 | (upbeat music)

Understand & Improve Memory Using Science-Based Tools | Huberman Lab Podcast #72

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