00:01
Okay, now let's get into
how emotion and biology
play a role together.
00:09
So what we want to figure out
is, is there a place
in the brain that is dealing
with all of our emotion?.
00:14
Is there a place in the
brain that is allowing us to
experience our emotion?
Is there a place in your brain
right now that is saying,
"I'm completely stressed out
about this MCAT exam."
And the answer really is,
"No."
So we know there is no
specific brain region
associated with a specific
emotion.
00:30
Therefore, for example,
there is no discussed center
of the brain.
00:34
There is, "No, I'm scared center
of the brain."
But what we have instead is
this really unique way
to express several different
emotions
through emotional circuits
that would involve
different brain structures.
00:45
It's kind of makes much more
sense and think about it,
is that you want to have
sometimes a different component
from each or more than just
one emotion.
00:52
Because there's a lot of
scenarios I think you can think
of where you're kind of happy,
you're kind of sad,
you're kind of scared,
you're kind of excited.
01:00
And all that's put into
a blender and you experience
that emotion that you are experience.
01:04
And it's hard to say,
"I'm feeling just fear."
"I'm feeling just happiness."
So by having these emotional
circuits we are allowed to
pull and draw from a bit
of those emotions to create
the ultimate final emotional
experience that you're getting.
01:18
And that's done through all
these networks and circuits
that are happening within
the brain.
01:22
Now that being said, you will
have some brain structures that
are involve in that process.
01:28
And we've highlighted some of
them here on this diagram.
01:30
And you can see we have
things like the thalamus,
the hypothalamus,
the frontal lobe,
the amygdala,
the hippocampus.
01:37
Even olfactory bulb
which is a part of your brain
dealing with this smell
of things that actually
really contribute to emotions
that you feel.
01:46
But a lot of times you've heard
of how scent or smell can
trigger a memory
or can trigger an emotion.
01:53
Which is why when you go to your
local candle shop and you have,
your calming candle and then
you'll have your chill candle.
02:00
Have your, you know, different
types of candles based on
scent that's because we have
established that smell
can impact emotion.
02:06
So what we're going to do,
we're going to highlight
some of these brain structures.
02:09
And we'll talk about what they
do and how they contribute
to our perception of emotion.
02:14
So the first one we will
look at is the limbic system.
02:17
And the limbic system is going
to come up and several lectures
we are going to have.
02:21
And it is quite important
for your MCAT exam.
02:23
So you should be quite familiar
with the components
of the limbic system.
02:26
How they are involved
with emotion.
02:27
And we're going to talk about
how they are involved
in other processes as well.
02:30
So the limbic system
is a collection of structures
found on both sides
of the thalamus, okay.
02:36
So if you go back to
the previous slide,
we'll look at that and you can
refer that diagram.
02:40
And you can have one in front
of you looking at, okay,
here's a thalamus and here
the limbic system is.
02:44
The structures within the limbic
system are appear to be primary
responsible for emotional
experiences.
02:50
So we're going to get into how
when you are presented
with an emotional experience.
02:55
Parts of the limbic
system are activated.
02:59
And there's different neurotransmitters
which will
release within the limbic
system,
dopamine being one of them.
03:05
Which provides pleasure.
03:07
And therefore,
we know the limbic system
is quite involved with things
like reinforcing
positive behavior.
03:13
We'll get into that
in more detail.
03:14
So the first specific structure
we are going to
talk about is amygdala.
03:18
This is the main structure
involved with emotion found
in the limbic system.
03:22
And it's surprisingly small.
03:24
So it's, about the size of an
almond or nothing much more than
an almond may be a kidney bean.
03:31
And it's found deep,
deep within your brain.
03:33
So this is something very
superficial on the top.
03:35
This is deep, deep
within the brain.
03:37
And we know that if you activate
this structure,
if it is stimulated,
that we are going to activate
the expression of fear
and aggression.
03:46
We also know in studies
and experiments where
the amygdala amygdala is damaged
or removed that you see
a removal of this fear
and aggression.
03:54
Okay, so this is an example in
research, in health research
where we look at damaged to
see the impact on function.
04:03
So great example of it is you
remove again amygdala you see
this direct impact which change
in our expression of fear
and aggression.
04:13
So here you can see a visual
diagram
looking at where you would see
the amygdala.
04:19
And you can see that it is quite
small and it is found deep
within the brain.
04:22
And this is what I meant by,
it's not found on the corticular
layers on the top.
04:25
Convoluted layers expand deeper
in the brain.
04:31
Now, let's talk about
the hypothalamus.
04:33
The hypothalamus is also a very
small structure
and it is very involved
with the amygdala.
04:38
So it communicates
with the amygdala
and prefrontal cortex.
04:41
Or the PFC, it's lot of times
you see it abbreviated.
04:44
These three structures
have this straight relationship
and they communicate a lot.
04:48
And that makes sense if
we're dealing with emotion.
04:50
You want this cross-talk.
04:51
So we know that the hypothalamus
controls a lot of the body
functions associated with emotion.
04:57
So we say the physiological
aspects of emotion.
05:00
Things like when you
saw that bear,
or you had your surprise MCAT party,
the increase in your
heart rate is sweating,
those changes are attributed
to changes in functions
or stimulation of
the hypothalamus.
05:14
And the prefrontal cortex
is very, very important.
05:16
And it is involved with a lot
of different functions.
05:19
Now in terms of where it's
located,
it's found at the brain.
05:23
That's the name pre.
05:24
Frontal which should be in front
of your head, right here.
05:27
Cortex.
05:28
It controls a lot of behavioral
aspects of emotion.
05:32
So how do you approach things.
05:34
How do you thinking
about things.
05:36
How do you avoiding
different things.
05:37
Obviously all things directly
related to emotion.
05:40
And it also helps
regulate emotion.
05:44
And it plays a role in
an executive function.
05:46
So, I'm throwing a lot
of terms around.
05:48
Let's walk through
a couple of those.
05:49
So an important term I want
you to understand
is executive function.
05:53
So what are we talking about
when we say executive function.
05:55
So let's break that down,
executive.
05:58
When you think of executive,
you think of somebody
that's higher up in the rungs
of say an organization.
06:03
So the big boss or the executive
brass at a company,
your company is somebody
that kind of runs the show
and makes the big decisions.
06:11
And related to function.
06:13
So executive function is
referring to as an individual,
these broad important choices
are being made
by the prefrontal cortex.
06:21
And so in terms of the emotion,
it's going to modulate
what you're experiencing.
06:26
And it's going to therefore,
direct what are the functional
roles that you're going to
do based on that emotion.
06:32
So how do we understand what
the prefrontal cortex does.
06:36
I'm going to bring
forth an example.
06:38
And this is a classic MCAT style
example that you would
need to know.
06:43
And this is about are good
friend Phinease Gage.
06:46
So you may have heard
this story before.
06:48
We are going to really quickly
bring you up to speed on that.
06:51
This is an example of us
understanding the function of
the brain based on damage.
06:56
So you got to backtrack a little
bit and think of you know,
fifty hundred years ago, we
didn't have the bio-technology
that we have today.
07:03
Today you have headaches and you
have an issue,
you go to your local hospital,
and you get an MRI
or CAT scan and they can look
at all these different ways
to bio-image your brain.
07:13
And we can use so many different
ways to examine changes
and function and what's
happening inside your body.
07:19
You got to think a 100 years ago
we didn't have access
to these types of tools.
07:24
So how would you figure out what
this portion of the brain
is doing versus that portion.
07:28
Really it's kind of barbaric
but what we would do
is look at an individual before.
07:33
If you had some type of record
and you looked at damage
that happened,
hopefully you didn't apply
that damage
versus what happens after
the damage.
07:40
So Phineas Gage was a railroad
worker.
07:44
And he was a very well
liked guy, very bright.
07:47
And he was sort of a foreman
and he was able to manage
his troops laying down tracks.
07:52
And one day while working on
the railway track,
there was an explosion.
07:57
And they have something called
a tampering rod which
is the long metal rod.
08:00
You know, I'm not a big railway
guy so I can't get
into the specifics of what
those are for.
08:04
But basically there was an
explosion and that explosion
caused that tampering
rod go fly in the air.
08:10
But on it's way to go through
the air, decided to go through
Phineas Gage's head.
08:15
And it actually entered his, it
actually entered below his cheek
and exited up through the top
of his frontal,
temple and frontal lobe.
08:25
That's got to hurt.
08:27
That's got to hurt a lot.
08:28
Now that's not something you
want happening to you hopefully
on a regular basis.
08:32
But this happened to
our friend Phineas.
08:33
And this brought forth
a really unique situation,
is we understood Phineas's
personality and behavior prior
to the accident and post accident.
08:44
And prior to the accident,
we know behaviorally speaking,
he was a great guy.
08:47
He was very well liked,
personable, intelligent.
08:50
And after the accident they
noticed these huge changes.
08:55
So they track these changes
and post hoc or afterwards
they realized where was
the damage to his brain.
09:02
And they realized that
was in his frontal lobe.
09:04
More specifically in
the prefrontal cortex.
09:06
And they are able to attribute
the behavioral change
to the damage that we saw
in those areas.
09:11
So again just to summarize.
09:13
We know what he was like before.
09:15
Tampering rod enters his brain.
09:17
Destroys and really damages
his prefrontal cortex
and the frontal lobe.
09:21
And then we see the resultant
personality change.
09:24
So we can make this indirect
relationship and say,
well that must mean that
is prefrontal cortex
is involved with these types
of behaviors because they've been
impacted by a metal rod through
the head.