May 25, 2023 • 26 mins
Do we really only use 10% of our brain? Can we classify ourselves as “left-brained” or “right-brained?” And can we really trust our memories? Notre Dame Psychology professor Jessica Payne breaks down truths vs. myths about the human brain with host Steven Schragis.
One Day University is a co-production of iHeart Podcasts and School of Humans. It is a Curiosity Podcast. You can sign up at the website OneDayU.com to become a member and access over 700 full length video lectures. You can also download their app. Once you’re a member, you can watch Professor Jessica Payne’s lecture, “What We Know About The Brain (And What We Don’t)”
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Speaker 1 (00:04):
My response to people who say, while else to sleep
when I'm dead is yes, you'll be dead a lot
sooner and a lot stupider in the meantime, because that's
what the science says.
Speaker 2 (00:20):
Welcome to One Day University talks with the world's most
engaging and inspiring professors discussing their most popular courses. This
podcast is your chance to discover some of our top
rated lectures on your own schedule. I'm Stephen Shregis. The
National Institutes of Health calls the brain the crown jewel
(00:41):
of the human body. It's the most complex organ we have,
controlling our behavior, memories, emotions, movements, and much more. There's
quite a lot we don't understand about the brain, and
even more surprisingly, some of the things we thought we
knew are actually myths. That's according to Notre Dame psychology
(01:01):
professor Jessica Paine, she has to talk for One Day
University called What we Know about the Brain and What
We Don't. Jessica directs the Sleep, Stress and Memory Lab
at Notre Dame, and before dispelling misinformation about the human brain,
she first explains the field of cognitive neuroscience.
Speaker 1 (01:28):
The way I like to explain it is it's a
blend or a hybrid really of classical cognitive psychology, where
we're trying to understand cognition, meaning memory, emotion, decision making, attention, concentration,
and then neuroscience, which is really the study of the
physical cells that make up the brain, and cognitive neuroscience
(01:52):
is still a relatively new field where we're trying to
put the two things together. So when we talk about
I'll just use memory as an example because that's my
area of expertise. As you're trying to remember things, what
regions of the brain are you leveraging to do that.
So we're trying to get at not just the behavioral
(02:12):
experimental aspect of what is a memory, how does it operate,
what can people retrieve, and why how long do memories last,
But we're also trying to understand the systems and the
structures in the brain that are going to participate in
those types of tasks.
Speaker 2 (02:30):
Not that many years ago, something called an fMRI was
invented and now it's used all the time. What is
that and why is it so important in this field?
Speaker 1 (02:40):
Well, and it's related to what I just said. So
when we studied cognitive issues back in the day, I
mean even as early the eighties the nineties, we didn't
have tools that could help us understand where things occurred
in the brain. So fMRI and other neuroimaging tools allow
us to image the brains at work. So while you're
(03:02):
performing memory task, for example, or maybe it's a language task.
Maybe you're bilingual and you're speaking in one language and
flipping to the other, we can look inside the brain
and determine what regions are active when you're performing these
different cognitive tasks. So we really didn't have the ability
to look inside the brain before that, at least not
(03:23):
an intact neurotypical brain. We were reliant on quote, normal
human subjects in psychology tasks and had to deal with
this black box in place of the brain. We just
didn't really know how to talk about the brain because
most neuroscience studies at that time were going on in
animals or in patients, and so we were able to
(03:44):
derive some conclusions from animals and patients. But now we're
able to study the neurotypical brain because fMRI is not dangerous.
You're using a magnet, there's no radiation or anything like that,
and so we're able to image the brain at work
on these different cognitive tasks that really brought the neuroscience
into cognitive neuroscience, at least in part.
Speaker 2 (04:04):
I've got a few questions now regarding so called facts
that a lot of people believe that perhaps aren't really true.
So I'll start with this one. Most people only use
ten percent of their brain.
Speaker 1 (04:17):
It has me crazy. Yep, you know, I honestly don't
even know where that came from. I've tried to trace
it back. It's very clearly misinformation. We are utilizing most
of our brains most of the time. So even if
you look at one of these language tasks, now that
we can use fMRI, you see that you're using a
whole bunch of different regions of the brain to produce
(04:39):
or comprehend language. Even when you retrieve a memory, you're
going to preferentially activate a region of the brain called
the hippocampus, which is probably the most important structure we
think for learning and memory. But it's not as if
it's the only structure. It collaborates with other structures all
over the place. In the frontal lobe, which is the
most recently evolved part of our brain, the at a lobe,
(05:00):
other regions of cortex to complete the act, say of
retrieving a memory. So I can't really think of any example,
even during sleep where you're not utilizing quite a bit
of your brain.
Speaker 2 (05:14):
You're telling me it's not true that when you sleep
your whole brain turns off and nothing much is happening,
not at all.
Speaker 1 (05:21):
In fact, I like to say nothing could be further
from the truth, because when you're asleep, and particularly when
you're in rapid eye movement sleep, some of these regions
that I was just talking about, like the memory and
surrounding cortical structures that are important for memory, they're just
wildly activated. Same with the amygdala, which is so important
for emotion and emotional learning and memory. They're in some
(05:43):
cases even more active than when people are wide awake.
Speaker 2 (05:48):
Jessica, you mentioned that our brains are never shut off.
Is that always a good thing? Is that sometimes a
bad thing?
Speaker 1 (05:54):
You know? It's a good question. I think it's a
good thing in the sense that the brain has a
lot of information to process, needs to not just encode
do information and store it for later reference, but it
needs to transform information in interesting ways so that we
can come up with these creative solutions to problems, as
I was saying, but I think the potential downside of
(06:15):
our active brains is when that activity turns into something maladaptive,
like rumination. And that's why I think it's better to
try to redirect our cognition in more useful ways, because
it can it really can backfire on people if you
can't stop thinking about something, can't stop flashing back on something.
(06:35):
This is pretty characteristic of a lot of different mental
health disorders. By the way, rumination or flashbacks when it
comes to negative events. You see that in anxiety disorders
like PTSD. You see rumination in anxiety and in depression.
So there's something really interesting about the brain being unconstrained
and sort of running a muck on you when the
content that's going through your head is negative.
Speaker 2 (06:56):
Next one right brain versus left brain. Except we've all
heard about what's the basis for it and is there
a reason there is?
Speaker 1 (07:05):
And in that case there's at least a good reason.
It turns out again, in neurologically normal people, there just
aren't that many interesting differences there. I mean, there's a
big one, which is language. And so for the majority
of people, something like ninety five plus percent of right handers,
and I think over seventy percent of left handers have
language lateralized to their left hemispheres, and that is true
(07:27):
in most people. But where the real you know, drawing
on the right side of the brain. And a lot
of these oversimplifications and the media came from, I think,
are based in what are known as split brain patient studies.
So these are fascinating patients who are quite rare that
actually have their hemispheres separated from one another. There's a
(07:47):
big white matter track that's called the corpus colosum that
connects the two hemispheres, and it's like an information super highway.
Its whole job is to really make sure the two
hemispheres communicate together all the time, and due to intractable epilepsy,
in some very rare patients, they will actually sever that
so that they separate the two hemispheres from one another
(08:10):
so that the seizures can't spread from one hemisphere to another.
And this is obviously only in very very rare cases
where medication isn't working, nothing else is working. But those patients,
if you meet them, and I've had the pleasure of
actually meeting one, you would never know that they actually
have two hemispheres that don't talk to each other. They're
very quote normal seeming, But if you design the right
(08:31):
kinds of tasks, that's where you see some of these
asymmetries where the right side of the brain tends to
be much better when it comes to visual and spatial
information and the left brain much more specialized when it
comes to language. Now, those types of strict asymmetries, though,
you just don't see in an intact brain where the
(08:52):
two hemispheres are communicating. So there's a little bit of
truth to it. I mean, certainly language is lateralized. The
right hemisphere may be a little bit better at dealing
with global processing, gestalts and this visual spatial ability I'm
talking about. But when I hear about consultants who are
on the road, you know, teaching people to be more
(09:12):
less right or left brain, there's just nothing to that.
It's real pop psychology.
Speaker 2 (09:18):
Let's keep going. Our memories are accurate snapshots of what
really happened in our past. Is there a reason to
doubt that?
Speaker 1 (09:27):
There's every reason to doubt that. In fact, we know
that they're not and I'm on the record just to
be controversial. At some memory conferences saying there's no such
thing as a memory. There's no such thing as a real, true,
verritical memory. In most cases, insofar as we're talking about
episodic memories or memories for the episodes and experiences of
our past, we know that we're incredibly biased as human
(09:50):
beings even when we're encoding or acquiring new information, and
that sort of bias only gets worse as you are
processing information over time. And I think it's much more
helpful to understand the memory system as a system that
really evolved more to help us figure out how to
problem solve in the future than it did to accurately
(10:11):
reflect the past. So it's not that it can't do that.
I mean, anybody who's been a student knows that you're
going to have to have a fairly accurate memory system
in order to perform well on tests. So it can
perform those tasks up to a point, especially with very
simplistic materials, But when it gets into you know, the
real world memories of people's pasts, they're not at all accurate.
(10:34):
And I don't think that they necessarily should be, because
I think the goal of that system is to encode
and store information in a flexible way, so that you
can use what you've learned, not just to spit it
back out in some high fidelity version of the way
you originally learned it, but to be able to use
it creatively and flexibly in this unpredictable world that's constantly
(10:57):
changing on us.
Speaker 2 (10:58):
I'm going to follow up a little that I've heard
you speak a bit about memories made during highly significant
emotional events. So, for instance, I'm one hundred percent sure
I know where I was when the innocent verdict in
the OJ Simpson case was released. Is my memory of
that probably accurate?
Speaker 1 (11:19):
It's probably not. And this is what's fascinating. I mean,
I'm convinced that I can tell you exactly where I
was and what happened to the detail during nine to eleven.
But we have run studies and multiple labs have done
this confirming that we are very confident in those memories.
But they're not much more accurate than any other types
(11:41):
of memories. They're just more vivid and more detailed, which
makes us more confident in them. And the way we
know that is because there have been studies done on
nine to eleven where people have been asked immediately after
the event what they remember, and then they've been followed
up later, and the memories change over time, just like
most normal memories do. So that's a fascinating finding that
(12:02):
the confidence we have in our most emotional memories is high,
but we're not necessarily much more accurate.
Speaker 2 (12:13):
After the break. How words actually can hurt you, and
why sleep deprived people make Jessica mad I'm just going
to ask for a couple of sentences about two other concepts,
(12:35):
mind wandering good or bad, and meditation good or bad,
or both.
Speaker 1 (12:42):
Wandering and actually mind wandering the answers both. Mind wandering
gets a bad rap, and in some sense deservedly so,
because most people think about mind wandering in the context
of say a student in a classroom who can't concentrate
because his or her mind is wandering, or an employ
at work who's not getting as much done because his
or her brain is mind wandering. So it can be
(13:04):
tied to distractability, and that makes it quote bad. But
mind wandering also is tied to creativity. So if your
mind is wandering about a problem that you're trying to solve,
or even just wandering when you don't have thoughts that
need to be constrained, you can come up with some
really cool and unusual ideas. So I think it's all
(13:24):
about the affective tone, the valance, whether it's positive or negative,
and sort of the regimented nature of your thoughts, whether
there's something happening in a repetitive way, which is again
more along the lines of rumination, or if what you're
being distracted by is completely unrelated to anything in your
life versus something that could be right. So it really
(13:45):
just depends on the context about whether that's good or bad,
whether that's distraction or whether that's the brain problem solving
in a way that could yield some useful insights.
Speaker 2 (13:54):
And meditation and meditation there's.
Speaker 1 (13:56):
A downside to everything. I mean, there are some stet
that have been looking at the downside of meditation, but
I'd say on the whole, especially if you're doing it
the way most Americans do, which is probably no more
than ten twenty thirty minutes a day max, it seems
to be extremely beneficial. There's evidence out there that suggests
(14:17):
that meditation even changes the brain, not just functionally, meaning
the way you process information that we can see using fMRI,
but even structurally, and you're building new neural tissue in
key emotion and emotion regulation areas of the brain like
the ventral medio prefernal cortex and the insula. So meditation
to me is one of the more interesting topics in
(14:40):
the neuroscience field right now, because what we know from
our research on stress is that stress can if it's
elevated for long enough and it's chronic enough, especially exposure
to stress hormones like cortisol. If it's really really high
and really chronic, you end up with problems, and you
end up with some neural deficits, including a reduction in
(15:01):
plasticity and even shrinkage in certain brain areas like the
hippocampus being so important for memory, and regions of the
ventromedial prefrontal cortex as well potentially. But when you do
something like meditate, which involves a relaxation component and a
breathing component, which is very helpful for dropping those stress hormones,
and then most, if not all, meditation techniques have an
(15:23):
attentional component where you're focusing over and over again on
the breath and if your mind wanders, you catch that,
but you nonjudgmentally come back to the mantra or to
the breath, and there's something about I believe the combination
of the breathing and the relaxation and the reduction in
andreenergic and tone of cortisol in addition to that attentional
(15:43):
piece that seems to create these beneficial again not just functional,
but structural changes in the brain, which makes it I think,
stronger and potentially more resilient to future negative emotional events
and threats in the future.
Speaker 2 (15:56):
Sticks and stones can break my bones, but words can
never harm me. My mother used to say that, I
thought it was true. Not so true, huh, not so true.
Speaker 1 (16:06):
Now, I don't think it's the worst thing for a
mom to say to her kid. If for kids, you know,
being bullied, I think you've got to do something. And
bullying is its own topic obviously, but that's not true.
I mean we know, in fact, in order to understand
social exclusion, in order to understand bias, I mean, even
getting into really difficult topics like racism, words are hurtful,
(16:28):
and I think there I'm drawing on social exclusion experiments
where what you see is that when people experience social pain, okay,
being teased, being bullied, being excluded, you actually see pain
regions of the brain becoming activated in very much the
same way, or at least a similar way to the
(16:48):
way they become activated when you're in physical pain. So
social pain is real, and it's experienced very similarly by
the brain to the way pain is. The reason for that,
I think is because we're a highly social species. We
evolved in social groups. We're incredibly dependent on our social networks,
and it's tough to feel excluded or to feel less
(17:12):
than and the brain data show that quite convincingly, I think.
So it's all the more reason we should care about
things like bias and discrimination and bullying, even when it's verbal.
Speaker 2 (17:24):
You explain that taking advil or aspirin when you're feeling
very badly about how you've been treated is sometimes as
effective as taking it when you have actual pain.
Speaker 1 (17:37):
Yeah, those studies are fascinating, and I think the phenomenal
logical experience of the participants is still a little bit
up for debate whether they actually feel better. I think
in some studies they suggest that people do actually say
they feel better, at others they don't. But what it
definitely seems to do is reduce the pain that people
experience as a function of social exclusion or other types
(18:00):
of social pain. So again, I think the message underlying
these studies that's so important is that social pain and
physical pain are very, very similar when it comes to
the way the brain processes these two different types of pain.
Meaning it's very real. It gets under the skin. These
words that supposedly can't hurt you really can get under
the skin to activate the same networks in your brain
(18:22):
that you activate if you put your hand on a
hot stove, and in the same way. Part of what
supports that is that if you take aspirin or advil
or senemtapin something like that, you end up reducing the
amount of brain activity that you typically see activated when
somebody is subjected to its socially painful stimulus.
Speaker 2 (18:40):
Here's something I know a lot of people wonder about dreaming.
Some people remember their dreams or seem to. Some people
never do, some people do sometimes Why is that? And
does everyone dream?
Speaker 1 (18:52):
So we think most people dream? I mean there are
certain stroke patients who may genuinely not dream, but most
people who think they don't. I love getting a hold
of them because we can bring them into the research laboratory,
hook them up to EEG electrodes, so we can see
whether they're sleeping or not and what stage of sleep
they're in. And if you wake people up periodically, especially
out of rapid eye movement sleep, people who usually don't
(19:16):
remember their dreams will invariably report dreams, and they surprise
themselves and it's really fun to see. So most, if
not virtually all of us dream, but there does seem
to be this very interesting difference in how regularly people
remember them. Some people remember them a lot, some people less.
There's some evidence that people who don't tend to remember
(19:36):
their dreams at all are better and deeper sleepers. But
I've also met people who remember their dreams periodically that
sleep quite well, and they report sleeping well, and their
EEG tells me the same thing. So I think there's
just natural human variation in that, just like there are
in so many of these domains, and it's a fascinating
area to study. It's one of my great passions for sure.
Speaker 2 (19:56):
Speaking of passion, there's something I've seen you get real
worked up about, and it's those people who talk about
denying themselves sleep. You call them the a sleep when
I'm dead group. Yes, why did they upset you so much?
What's going on there?
Speaker 1 (20:11):
Yeah, and you're right, you have a good eye, because
I think I've nearly like followed off the stage thrown
my microphone. And my response to people who say, well, else,
just sleep when I'm dead is yes, you'll be dead
a lot sooner and a lot stupider in the meantime,
because that's what the science says. Yes. And I get
angry about that because it's a myth, it's a cultural myth.
It's not backed up by data. These people who seem
(20:33):
to think that they're not just find but great on
three and four hours of sleep are so difficult to find.
I have had many people tell me they're that person,
but I haven't actually found one of these short sleepers yet.
I mean they exist. Again, the amount of sleep we
need seems to be normally distributed, so most of us
need somewhere between seven and nine. But if you go out,
you know, to standard deviations on this, you know, normal
(20:54):
distribution or Bell curve, you can find people who probably
really only need four. But again, they're just so satistically
rare that I can't find them. And yet I find
plenty of people who brag about it. Right, it's the
CEO who's you know, constantly working. It's the student at
Notre Dame or prior to that, Harvard who thought they
were doing the right thing by sleep depriving themselves to
(21:15):
learn more. And I'm a memory researcher. The two worst
things you can do for your ability to learn and
remember are one cram and two sleep deprive yourself while
you're doing it. So the two best things to do
or distribute or stagger your practice across multiple study episodes
and to sleep on it. It's frustrating to me because
it's based, I think in this cultural ideology that we
(21:39):
have where we really think that we're only worth as
much as our human capital, you know, and so we
need to be using every single ounce of our time
and energy to produce. And I have a lot of
issues with that just socially, but I have a big
issue with the fact that if you want people to
be more productive, you need to do the revolutionary thing
of let them sleep, let them have time with their families,
(22:02):
let them have down time, let them exercise. It's about efficiency,
and the brain simply can't perform very well if it's
highly stressed out and sleep deprived. That's the world we're
living in We've got most companies out there thinking that
that's a good thing, when the truth is it's a
bad thing, which is why I've gotten into so much
corporate work and doing a lot of leadership trainings in
across domains, but especially in healthcare, where it's particularly upsetting
(22:25):
because I feel like they ought to know better. So
sleeping is one of the best things you can do
for your cognitive performance. I think it's one of the
most powerful tools we have at our disposal. I've just
been waiting for our kind of corporate culture to catch
up with what the neuroscience facts say.
Speaker 2 (22:39):
I've got one more untrue statement. We're born with a
certain number of neurons in our brain, and that's all
we're going to get, right.
Speaker 1 (22:48):
And isn't that great that that turned out to not
be true. Yes, it used to just be like it
was all downhill, And so now we know. There are
two main types of plasticity in the brain, and one
is called neurogenesis, and that's the one you're referring to.
That's the literal birth of new brain cells which seem
to become functionally active and relevant, especially in memory systems.
(23:08):
And neurogenesis seems to continue even into the eighties. At
least some studies really strongly suggest that the other type
of plasticity is the dendrites, which are sort of part
of the neuron that has a lot of different connections,
and it goes out and makes connections with other neurons
that sort of form our ability to have thoughts and
store memories and do everything else. That also can change,
(23:32):
can shrink or grow in the same way neurogenesis can
sort of be reduced or increased, and the things that
inhibit that those two to different types of plasticity seem
to be quite similar. So, for instance, if you're highly
sleep deprived and extraordinarily stressed for a long time, you're
actually going to get hit on both of those fronts.
So the good news, though, is that we do have
(23:52):
plastic abilities throughout the lifespan, unlike we once thought. The
bad news is we are still, i think, living in
social conditions which aren't always benefiting those two types of plasticity.
Speaker 2 (24:04):
Okay, I've got one more question for you. What's something
we still don't know about the brain that you'd really
like to know because you'd find it fascinating, but we
just can't answer it.
Speaker 1 (24:16):
I mean, there are so many things. Really, I would
like to know definitively how memories actually work. I would
like to know what dreaming really is. There's new literature
suggesting that there's such a phenomenon as local sleep, where
you've got certain patches of the brain sleeping or sleeping
differently than other patches of the brain. What I love
about neuroscience and what I love about the brain is
(24:39):
I think it's by far the most complex system in
the world, certainly the most complex biological one, and we
just don't have a huge amount of understanding yet. So
I'm always trying to recruit people into science to help
us figure it out. And there are literally probably an
infinite number of questions to ask about it that we're
not even really asking yet.
Speaker 2 (25:00):
Now, say, Jessica, thank you so much for doing this.
We really appreciate it. I love learning about this stuff,
and I know our listeners do too.
Speaker 1 (25:07):
You're welcome, wonderful seeing you, Stephen.
Speaker 2 (25:10):
Thanks for joining us here at One Day University. Sign
up at our website one dayu dot com to become
a member and access over seven hundred full length video
lectures from the world's finest professors. You can also download
our app. There you can watch Notre Dame Professor Jessica
Pain's lectures on the brain, the science of sleep, and more.
(25:33):
Join us next time. When we talk about the wives
of Henry, ye, I.
Speaker 3 (25:37):
Think that they can be easily summed up or described
in one word. You know, one's the temptress, or one's
the loyal wife, one's the saint. They're too often talked
about just sort of as these wives who are only
understood in relationship to Henry and their mostly terrible ends,
when in fact they have these rich lives that go
beyond that.
Speaker 2 (25:57):
One Day University is a production of iHeart Podcasts and
School of Humans. If you're enjoying the show, leave a
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out other Curiosity podcasts to learn about history, pop culture,
true crime, and more. School of Humans
My response to people who say, while else to sleep
when I'm dead is yes, you'll be dead a lot
sooner and a lot stupider in the meantime, because that's
what the science says.
Speaker 2 (00:20):
Welcome to One Day University talks with the world's most
engaging and inspiring professors discussing their most popular courses. This
podcast is your chance to discover some of our top
rated lectures on your own schedule. I'm Stephen Shregis. The
National Institutes of Health calls the brain the crown jewel
(00:41):
of the human body. It's the most complex organ we have,
controlling our behavior, memories, emotions, movements, and much more. There's
quite a lot we don't understand about the brain, and
even more surprisingly, some of the things we thought we
knew are actually myths. That's according to Notre Dame psychology
(01:01):
professor Jessica Paine, she has to talk for One Day
University called What we Know about the Brain and What
We Don't. Jessica directs the Sleep, Stress and Memory Lab
at Notre Dame, and before dispelling misinformation about the human brain,
she first explains the field of cognitive neuroscience.
Speaker 1 (01:28):
The way I like to explain it is it's a
blend or a hybrid really of classical cognitive psychology, where
we're trying to understand cognition, meaning memory, emotion, decision making, attention, concentration,
and then neuroscience, which is really the study of the
physical cells that make up the brain, and cognitive neuroscience
(01:52):
is still a relatively new field where we're trying to
put the two things together. So when we talk about
I'll just use memory as an example because that's my
area of expertise. As you're trying to remember things, what
regions of the brain are you leveraging to do that.
So we're trying to get at not just the behavioral
(02:12):
experimental aspect of what is a memory, how does it operate,
what can people retrieve, and why how long do memories last,
But we're also trying to understand the systems and the
structures in the brain that are going to participate in
those types of tasks.
Speaker 2 (02:30):
Not that many years ago, something called an fMRI was
invented and now it's used all the time. What is
that and why is it so important in this field?
Speaker 1 (02:40):
Well, and it's related to what I just said. So
when we studied cognitive issues back in the day, I
mean even as early the eighties the nineties, we didn't
have tools that could help us understand where things occurred
in the brain. So fMRI and other neuroimaging tools allow
us to image the brains at work. So while you're
(03:02):
performing memory task, for example, or maybe it's a language task.
Maybe you're bilingual and you're speaking in one language and
flipping to the other, we can look inside the brain
and determine what regions are active when you're performing these
different cognitive tasks. So we really didn't have the ability
to look inside the brain before that, at least not
(03:23):
an intact neurotypical brain. We were reliant on quote, normal
human subjects in psychology tasks and had to deal with
this black box in place of the brain. We just
didn't really know how to talk about the brain because
most neuroscience studies at that time were going on in
animals or in patients, and so we were able to
(03:44):
derive some conclusions from animals and patients. But now we're
able to study the neurotypical brain because fMRI is not dangerous.
You're using a magnet, there's no radiation or anything like that,
and so we're able to image the brain at work
on these different cognitive tasks that really brought the neuroscience
into cognitive neuroscience, at least in part.
Speaker 2 (04:04):
I've got a few questions now regarding so called facts
that a lot of people believe that perhaps aren't really true.
So I'll start with this one. Most people only use
ten percent of their brain.
Speaker 1 (04:17):
It has me crazy. Yep, you know, I honestly don't
even know where that came from. I've tried to trace
it back. It's very clearly misinformation. We are utilizing most
of our brains most of the time. So even if
you look at one of these language tasks, now that
we can use fMRI, you see that you're using a
whole bunch of different regions of the brain to produce
(04:39):
or comprehend language. Even when you retrieve a memory, you're
going to preferentially activate a region of the brain called
the hippocampus, which is probably the most important structure we
think for learning and memory. But it's not as if
it's the only structure. It collaborates with other structures all
over the place. In the frontal lobe, which is the
most recently evolved part of our brain, the at a lobe,
(05:00):
other regions of cortex to complete the act, say of
retrieving a memory. So I can't really think of any example,
even during sleep where you're not utilizing quite a bit
of your brain.
Speaker 2 (05:14):
You're telling me it's not true that when you sleep
your whole brain turns off and nothing much is happening,
not at all.
Speaker 1 (05:21):
In fact, I like to say nothing could be further
from the truth, because when you're asleep, and particularly when
you're in rapid eye movement sleep, some of these regions
that I was just talking about, like the memory and
surrounding cortical structures that are important for memory, they're just
wildly activated. Same with the amygdala, which is so important
for emotion and emotional learning and memory. They're in some
(05:43):
cases even more active than when people are wide awake.
Speaker 2 (05:48):
Jessica, you mentioned that our brains are never shut off.
Is that always a good thing? Is that sometimes a
bad thing?
Speaker 1 (05:54):
You know? It's a good question. I think it's a
good thing in the sense that the brain has a
lot of information to process, needs to not just encode
do information and store it for later reference, but it
needs to transform information in interesting ways so that we
can come up with these creative solutions to problems, as
I was saying, but I think the potential downside of
(06:15):
our active brains is when that activity turns into something maladaptive,
like rumination. And that's why I think it's better to
try to redirect our cognition in more useful ways, because
it can it really can backfire on people if you
can't stop thinking about something, can't stop flashing back on something.
(06:35):
This is pretty characteristic of a lot of different mental
health disorders. By the way, rumination or flashbacks when it
comes to negative events. You see that in anxiety disorders
like PTSD. You see rumination in anxiety and in depression.
So there's something really interesting about the brain being unconstrained
and sort of running a muck on you when the
content that's going through your head is negative.
Speaker 2 (06:56):
Next one right brain versus left brain. Except we've all
heard about what's the basis for it and is there
a reason there is?
Speaker 1 (07:05):
And in that case there's at least a good reason.
It turns out again, in neurologically normal people, there just
aren't that many interesting differences there. I mean, there's a
big one, which is language. And so for the majority
of people, something like ninety five plus percent of right handers,
and I think over seventy percent of left handers have
language lateralized to their left hemispheres, and that is true
(07:27):
in most people. But where the real you know, drawing
on the right side of the brain. And a lot
of these oversimplifications and the media came from, I think,
are based in what are known as split brain patient studies.
So these are fascinating patients who are quite rare that
actually have their hemispheres separated from one another. There's a
(07:47):
big white matter track that's called the corpus colosum that
connects the two hemispheres, and it's like an information super highway.
Its whole job is to really make sure the two
hemispheres communicate together all the time, and due to intractable epilepsy,
in some very rare patients, they will actually sever that
so that they separate the two hemispheres from one another
(08:10):
so that the seizures can't spread from one hemisphere to another.
And this is obviously only in very very rare cases
where medication isn't working, nothing else is working. But those patients,
if you meet them, and I've had the pleasure of
actually meeting one, you would never know that they actually
have two hemispheres that don't talk to each other. They're
very quote normal seeming, But if you design the right
(08:31):
kinds of tasks, that's where you see some of these
asymmetries where the right side of the brain tends to
be much better when it comes to visual and spatial
information and the left brain much more specialized when it
comes to language. Now, those types of strict asymmetries, though,
you just don't see in an intact brain where the
(08:52):
two hemispheres are communicating. So there's a little bit of
truth to it. I mean, certainly language is lateralized. The
right hemisphere may be a little bit better at dealing
with global processing, gestalts and this visual spatial ability I'm
talking about. But when I hear about consultants who are
on the road, you know, teaching people to be more
(09:12):
less right or left brain, there's just nothing to that.
It's real pop psychology.
Speaker 2 (09:18):
Let's keep going. Our memories are accurate snapshots of what
really happened in our past. Is there a reason to
doubt that?
Speaker 1 (09:27):
There's every reason to doubt that. In fact, we know
that they're not and I'm on the record just to
be controversial. At some memory conferences saying there's no such
thing as a memory. There's no such thing as a real, true,
verritical memory. In most cases, insofar as we're talking about
episodic memories or memories for the episodes and experiences of
our past, we know that we're incredibly biased as human
(09:50):
beings even when we're encoding or acquiring new information, and
that sort of bias only gets worse as you are
processing information over time. And I think it's much more
helpful to understand the memory system as a system that
really evolved more to help us figure out how to
problem solve in the future than it did to accurately
(10:11):
reflect the past. So it's not that it can't do that.
I mean, anybody who's been a student knows that you're
going to have to have a fairly accurate memory system
in order to perform well on tests. So it can
perform those tasks up to a point, especially with very
simplistic materials, But when it gets into you know, the
real world memories of people's pasts, they're not at all accurate.
(10:34):
And I don't think that they necessarily should be, because
I think the goal of that system is to encode
and store information in a flexible way, so that you
can use what you've learned, not just to spit it
back out in some high fidelity version of the way
you originally learned it, but to be able to use
it creatively and flexibly in this unpredictable world that's constantly
(10:57):
changing on us.
Speaker 2 (10:58):
I'm going to follow up a little that I've heard
you speak a bit about memories made during highly significant
emotional events. So, for instance, I'm one hundred percent sure
I know where I was when the innocent verdict in
the OJ Simpson case was released. Is my memory of
that probably accurate?
Speaker 1 (11:19):
It's probably not. And this is what's fascinating. I mean,
I'm convinced that I can tell you exactly where I
was and what happened to the detail during nine to eleven.
But we have run studies and multiple labs have done
this confirming that we are very confident in those memories.
But they're not much more accurate than any other types
(11:41):
of memories. They're just more vivid and more detailed, which
makes us more confident in them. And the way we
know that is because there have been studies done on
nine to eleven where people have been asked immediately after
the event what they remember, and then they've been followed
up later, and the memories change over time, just like
most normal memories do. So that's a fascinating finding that
(12:02):
the confidence we have in our most emotional memories is high,
but we're not necessarily much more accurate.
Speaker 2 (12:13):
After the break. How words actually can hurt you, and
why sleep deprived people make Jessica mad I'm just going
to ask for a couple of sentences about two other concepts,
(12:35):
mind wandering good or bad, and meditation good or bad,
or both.
Speaker 1 (12:42):
Wandering and actually mind wandering the answers both. Mind wandering
gets a bad rap, and in some sense deservedly so,
because most people think about mind wandering in the context
of say a student in a classroom who can't concentrate
because his or her mind is wandering, or an employ
at work who's not getting as much done because his
or her brain is mind wandering. So it can be
(13:04):
tied to distractability, and that makes it quote bad. But
mind wandering also is tied to creativity. So if your
mind is wandering about a problem that you're trying to solve,
or even just wandering when you don't have thoughts that
need to be constrained, you can come up with some
really cool and unusual ideas. So I think it's all
(13:24):
about the affective tone, the valance, whether it's positive or negative,
and sort of the regimented nature of your thoughts, whether
there's something happening in a repetitive way, which is again
more along the lines of rumination, or if what you're
being distracted by is completely unrelated to anything in your
life versus something that could be right. So it really
(13:45):
just depends on the context about whether that's good or bad,
whether that's distraction or whether that's the brain problem solving
in a way that could yield some useful insights.
Speaker 2 (13:54):
And meditation and meditation there's.
Speaker 1 (13:56):
A downside to everything. I mean, there are some stet
that have been looking at the downside of meditation, but
I'd say on the whole, especially if you're doing it
the way most Americans do, which is probably no more
than ten twenty thirty minutes a day max, it seems
to be extremely beneficial. There's evidence out there that suggests
(14:17):
that meditation even changes the brain, not just functionally, meaning
the way you process information that we can see using fMRI,
but even structurally, and you're building new neural tissue in
key emotion and emotion regulation areas of the brain like
the ventral medio prefernal cortex and the insula. So meditation
to me is one of the more interesting topics in
(14:40):
the neuroscience field right now, because what we know from
our research on stress is that stress can if it's
elevated for long enough and it's chronic enough, especially exposure
to stress hormones like cortisol. If it's really really high
and really chronic, you end up with problems, and you
end up with some neural deficits, including a reduction in
(15:01):
plasticity and even shrinkage in certain brain areas like the
hippocampus being so important for memory, and regions of the
ventromedial prefrontal cortex as well potentially. But when you do
something like meditate, which involves a relaxation component and a
breathing component, which is very helpful for dropping those stress hormones,
and then most, if not all, meditation techniques have an
(15:23):
attentional component where you're focusing over and over again on
the breath and if your mind wanders, you catch that,
but you nonjudgmentally come back to the mantra or to
the breath, and there's something about I believe the combination
of the breathing and the relaxation and the reduction in
andreenergic and tone of cortisol in addition to that attentional
(15:43):
piece that seems to create these beneficial again not just functional,
but structural changes in the brain, which makes it I think,
stronger and potentially more resilient to future negative emotional events
and threats in the future.
Speaker 2 (15:56):
Sticks and stones can break my bones, but words can
never harm me. My mother used to say that, I
thought it was true. Not so true, huh, not so true.
Speaker 1 (16:06):
Now, I don't think it's the worst thing for a
mom to say to her kid. If for kids, you know,
being bullied, I think you've got to do something. And
bullying is its own topic obviously, but that's not true.
I mean we know, in fact, in order to understand
social exclusion, in order to understand bias, I mean, even
getting into really difficult topics like racism, words are hurtful,
(16:28):
and I think there I'm drawing on social exclusion experiments
where what you see is that when people experience social pain, okay,
being teased, being bullied, being excluded, you actually see pain
regions of the brain becoming activated in very much the
same way, or at least a similar way to the
(16:48):
way they become activated when you're in physical pain. So
social pain is real, and it's experienced very similarly by
the brain to the way pain is. The reason for that,
I think is because we're a highly social species. We
evolved in social groups. We're incredibly dependent on our social networks,
and it's tough to feel excluded or to feel less
(17:12):
than and the brain data show that quite convincingly, I think.
So it's all the more reason we should care about
things like bias and discrimination and bullying, even when it's verbal.
Speaker 2 (17:24):
You explain that taking advil or aspirin when you're feeling
very badly about how you've been treated is sometimes as
effective as taking it when you have actual pain.
Speaker 1 (17:37):
Yeah, those studies are fascinating, and I think the phenomenal
logical experience of the participants is still a little bit
up for debate whether they actually feel better. I think
in some studies they suggest that people do actually say
they feel better, at others they don't. But what it
definitely seems to do is reduce the pain that people
experience as a function of social exclusion or other types
(18:00):
of social pain. So again, I think the message underlying
these studies that's so important is that social pain and
physical pain are very, very similar when it comes to
the way the brain processes these two different types of pain.
Meaning it's very real. It gets under the skin. These
words that supposedly can't hurt you really can get under
the skin to activate the same networks in your brain
(18:22):
that you activate if you put your hand on a
hot stove, and in the same way. Part of what
supports that is that if you take aspirin or advil
or senemtapin something like that, you end up reducing the
amount of brain activity that you typically see activated when
somebody is subjected to its socially painful stimulus.
Speaker 2 (18:40):
Here's something I know a lot of people wonder about dreaming.
Some people remember their dreams or seem to. Some people
never do, some people do sometimes Why is that? And
does everyone dream?
Speaker 1 (18:52):
So we think most people dream? I mean there are
certain stroke patients who may genuinely not dream, but most
people who think they don't. I love getting a hold
of them because we can bring them into the research laboratory,
hook them up to EEG electrodes, so we can see
whether they're sleeping or not and what stage of sleep
they're in. And if you wake people up periodically, especially
out of rapid eye movement sleep, people who usually don't
(19:16):
remember their dreams will invariably report dreams, and they surprise
themselves and it's really fun to see. So most, if
not virtually all of us dream, but there does seem
to be this very interesting difference in how regularly people
remember them. Some people remember them a lot, some people less.
There's some evidence that people who don't tend to remember
(19:36):
their dreams at all are better and deeper sleepers. But
I've also met people who remember their dreams periodically that
sleep quite well, and they report sleeping well, and their
EEG tells me the same thing. So I think there's
just natural human variation in that, just like there are
in so many of these domains, and it's a fascinating
area to study. It's one of my great passions for sure.
Speaker 2 (19:56):
Speaking of passion, there's something I've seen you get real
worked up about, and it's those people who talk about
denying themselves sleep. You call them the a sleep when
I'm dead group. Yes, why did they upset you so much?
What's going on there?
Speaker 1 (20:11):
Yeah, and you're right, you have a good eye, because
I think I've nearly like followed off the stage thrown
my microphone. And my response to people who say, well, else,
just sleep when I'm dead is yes, you'll be dead
a lot sooner and a lot stupider in the meantime,
because that's what the science says. Yes. And I get
angry about that because it's a myth, it's a cultural myth.
It's not backed up by data. These people who seem
(20:33):
to think that they're not just find but great on
three and four hours of sleep are so difficult to find.
I have had many people tell me they're that person,
but I haven't actually found one of these short sleepers yet.
I mean they exist. Again, the amount of sleep we
need seems to be normally distributed, so most of us
need somewhere between seven and nine. But if you go out,
you know, to standard deviations on this, you know, normal
(20:54):
distribution or Bell curve, you can find people who probably
really only need four. But again, they're just so satistically
rare that I can't find them. And yet I find
plenty of people who brag about it. Right, it's the
CEO who's you know, constantly working. It's the student at
Notre Dame or prior to that, Harvard who thought they
were doing the right thing by sleep depriving themselves to
(21:15):
learn more. And I'm a memory researcher. The two worst
things you can do for your ability to learn and
remember are one cram and two sleep deprive yourself while
you're doing it. So the two best things to do
or distribute or stagger your practice across multiple study episodes
and to sleep on it. It's frustrating to me because
it's based, I think in this cultural ideology that we
(21:39):
have where we really think that we're only worth as
much as our human capital, you know, and so we
need to be using every single ounce of our time
and energy to produce. And I have a lot of
issues with that just socially, but I have a big
issue with the fact that if you want people to
be more productive, you need to do the revolutionary thing
of let them sleep, let them have time with their families,
(22:02):
let them have down time, let them exercise. It's about efficiency,
and the brain simply can't perform very well if it's
highly stressed out and sleep deprived. That's the world we're
living in We've got most companies out there thinking that
that's a good thing, when the truth is it's a
bad thing, which is why I've gotten into so much
corporate work and doing a lot of leadership trainings in
across domains, but especially in healthcare, where it's particularly upsetting
(22:25):
because I feel like they ought to know better. So
sleeping is one of the best things you can do
for your cognitive performance. I think it's one of the
most powerful tools we have at our disposal. I've just
been waiting for our kind of corporate culture to catch
up with what the neuroscience facts say.
Speaker 2 (22:39):
I've got one more untrue statement. We're born with a
certain number of neurons in our brain, and that's all
we're going to get, right.
Speaker 1 (22:48):
And isn't that great that that turned out to not
be true. Yes, it used to just be like it
was all downhill, And so now we know. There are
two main types of plasticity in the brain, and one
is called neurogenesis, and that's the one you're referring to.
That's the literal birth of new brain cells which seem
to become functionally active and relevant, especially in memory systems.
(23:08):
And neurogenesis seems to continue even into the eighties. At
least some studies really strongly suggest that the other type
of plasticity is the dendrites, which are sort of part
of the neuron that has a lot of different connections,
and it goes out and makes connections with other neurons
that sort of form our ability to have thoughts and
store memories and do everything else. That also can change,
(23:32):
can shrink or grow in the same way neurogenesis can
sort of be reduced or increased, and the things that
inhibit that those two to different types of plasticity seem
to be quite similar. So, for instance, if you're highly
sleep deprived and extraordinarily stressed for a long time, you're
actually going to get hit on both of those fronts.
So the good news, though, is that we do have
(23:52):
plastic abilities throughout the lifespan, unlike we once thought. The
bad news is we are still, i think, living in
social conditions which aren't always benefiting those two types of plasticity.
Speaker 2 (24:04):
Okay, I've got one more question for you. What's something
we still don't know about the brain that you'd really
like to know because you'd find it fascinating, but we
just can't answer it.
Speaker 1 (24:16):
I mean, there are so many things. Really, I would
like to know definitively how memories actually work. I would
like to know what dreaming really is. There's new literature
suggesting that there's such a phenomenon as local sleep, where
you've got certain patches of the brain sleeping or sleeping
differently than other patches of the brain. What I love
about neuroscience and what I love about the brain is
(24:39):
I think it's by far the most complex system in
the world, certainly the most complex biological one, and we
just don't have a huge amount of understanding yet. So
I'm always trying to recruit people into science to help
us figure it out. And there are literally probably an
infinite number of questions to ask about it that we're
not even really asking yet.
Speaker 2 (25:00):
Now, say, Jessica, thank you so much for doing this.
We really appreciate it. I love learning about this stuff,
and I know our listeners do too.
Speaker 1 (25:07):
You're welcome, wonderful seeing you, Stephen.
Speaker 2 (25:10):
Thanks for joining us here at One Day University. Sign
up at our website one dayu dot com to become
a member and access over seven hundred full length video
lectures from the world's finest professors. You can also download
our app. There you can watch Notre Dame Professor Jessica
Pain's lectures on the brain, the science of sleep, and more.
(25:33):
Join us next time. When we talk about the wives
of Henry, ye, I.
Speaker 3 (25:37):
Think that they can be easily summed up or described
in one word. You know, one's the temptress, or one's
the loyal wife, one's the saint. They're too often talked
about just sort of as these wives who are only
understood in relationship to Henry and their mostly terrible ends,
when in fact they have these rich lives that go
beyond that.
Speaker 2 (25:57):
One Day University is a production of iHeart Podcasts and
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