So let's get into the CNS,
the central nervous system, that's your brain
and your spinal cord. Your brain and your spinal cord are
your central processing unit. Now, I've grayed out some stuff because I don't have time to talk
about everything I want to talk about
that's germane to your test so I want to get focused and be appreciative of your
time
and your attendance and your attention. So there's a hind brain. Well all
all animals that, you know, we know of, think a lizards got a hind brain,
right, birds got a hind brain, dolphin got a hind brain, monkey got a hind brain, human gotta Hamre muggy got a high-ranking we
got a hind brain, right?
It's your basic level of survival, right? You got your cerebellum, your medulla, your pons,
you get knocked back here in the hindbrain hard enough you die
because those functions are parasympathetic and they're controlled by those
structures and your hindbrain.
Those are absolutely crucial to functioning physically.
You lose those, you go into coma,
right, you become unresponsive. If it's
damage is extensive enough you die. Midbrain!
So we've got a small area that deals with dopamine regulation
and voluntary muscular control and that's a little bit more advanced.
Not every little creature got a midbrain.
Worm. Every little creature you think about it in terms of
other species. What have they got that we don't got,
or more properly what have we got that they don't got?
We got forebrain like nobody's business.
We got proportionately more forebrain
then every other species. Not in terms of mass,
in terms of ratio, right? Quail got a bigger head
than human, right? Got a bigger brain. But proportionately we got way more forebrain.
Forebrain seems to be what makes us particularly
human. That makes us really adaptive. If you go back to the functionalist school,
you all remember that, right, should remember that for your test, anybody know what name is
associated with functionalism?
William James, that's it, thank you girl, hallelujah, can I get an amen?
Yes, forebrain seems to make us more functional than all other species.
Why doesn't monkey rule the world? Like Planet of the Apes?
Because monkey hasn't got as much forebrain as we do.
We're smarter than monkey in different ways. We have abstract thinking
and monkey we don't think has that much abstract thinking. So now we're talking
about
a large section with many parts generating what we consider as human beings
to be higher functions. That isn't to say we're better creatures than monkey
because some people would debate that all creatures are equally
valuable in the scheme of things. Others would say, no, we eat some of them
and too bad for them and that's a debate I'm not getting into. What I'm saying is
proportionally our brain
has functionalities that we take as human beings to be very important to our
survival
and adaptivity to situations. So one area is the thalamus.
So I'm going to point you to some specific areas,
not all of them by any stretch will we cover. The brain is full of structures and when
we're talking about structures what we're really talking about is
neurons located in different areas. They're all neurons
but there's different kinds of neurons, right, and they have different functions
and their location
seems to be important or at least the development of where they are located
seems to have functionality. So all sensory input but smell is
integrated and sorted so you can kind of look at that as a junction box,
right? You got everything but smell, well why not smell? Cause smell's right here in your brain
anyway,
right? But sight goes through it because sight has to be rerouted.
Touch, sound.
So those activate various areas of your brain and they're also routed to
other areas of your brain. The reason you can hear sound
as more than just a tone or noise and discriminate, and discriminate in this case
is good,
we're talking about stimulus discrimination, not social discrimination which is bad, we're talking
about being able to understand that a sound is a
tone versus a word, taking a word to a poem
versus a memo, understanding different languages,
that's because it's routed, this information is routed to different areas of your
brain
through the use of interneurons. Hypothalamus got him a little asterisk beside him.
Hypothalamus is a pea-sized gland below the thalamus.
Hypothalamus, thalamus, hypothalamus, look,
I even put the hypothalamus right below the thalamus. Wasn't that thoughtful of me?
Help you remember that. Pea-sized
gland below the thalamus controls basic biological needs.
How you going to remember that? The four f's: fighting
fleeing, feeding, and reproduction - all
part of the limbic system, right? So it turns out that this little tiny pea-size gland
is critical for our functioning and continuation as a species,
as an individual you got to go if you're threatened
or you got to fight if you're threatened but as an individual collectively
we need to make more of us, right? So
reproduction has to be partly biological. Humans have a lot more choice
in mating
than other species do, right? We have a lot to control. Some of us don't
exercise control,
and engage in horrific kinds of behaviors
that are socially inappropriate but we have more control if we decide to exercise
it than almost every other
animal on the planet. You all have a wonderful day. We'll finish this up on
Wednesday!
I wanted to emphasize, somebody had a really good question after class and I
appreciate those. If you feel empowered ask during class,
I can make those clarifications, but if you ask after class, I'll be happy to clarify for the
class cause if you've got a question
likely somebody else does and if this is review for you, good.
Extra review is what helps you do well on a test. So your essential nervous system
is your brain and your spinal cord, right? CNS, and
your peripheral nervous system is all of that which is outside of it.
Your PNS, which I thought was a catchy little thing to help you remember it,
right? So, your peripheral nervous system and your central nervous system
are actually integrated. They have separate functions but clearly they cannot be
independent of each other. So when we broke down the peripheral nervous system
we're talking about divisions that also overlap a little bit but for
the point of view of the test and understanding the systems,
the divisions are very helpful. Somatic is
where you have voluntary control over functions of your body.
Autonomic, I liken to automatic,
because it works without your conscious awareness. It keeps you alive,
keeps you breathing, keeps your heart beating, keeps you digesting food, keeps your
metabolism
going and usually the system, subsystem that's in charge of all that
is the parasympathetic system. It's kind of sympathetic, it keeps you going.
You face a threat in your environment, whether it's real physical threat, you
think you might be hurt or killed,
car crash, assault, military
operations, some kind of a natural disaster, tornado,
hurricane, earthquake like in South Carolina, you're going to get a shot of
adrenaline.
A fight or flight response will occur and internally, psychologically, if you perceive a
threat that's not external,
it could be a fear of being embarrassed, a fear of being rejected,
a fear of feeling like you feel, you can get an adrenaline response too because your
brain is perceiving it as though it is a
legitimate threat and it's going to flood you with adrenaline and glucocorticoids.
Sympathetic nervous system is going to take care of you at that moment so
moving on forward, I think that'll help us tie it together if will look a little bit
more at the parasympathetic. You don't need to know this for your test.
Parasympathetic we got slowing your heart beat to what it is normally, your
baseline heart beat.
you got flow of saliva which you need to keep your mouth lubricated so you can masticate
and chew food and not choke to death on it. Constricts your bronchi,
stimulates your peristalsis, and that's what we were talking about before,
digestion,
moving the poo through the system, right, stimulating the release of bile,
contracts the bladder, all of that stuff. There's a link that's
clogging this up. There we go.
And the sympathetic, when you need it,
you're going to get a shot of adrenaline and other glucocorticoids,
dilating your pupils, inhibiting the flow of saliva, accelerating your heart rate. Why do you
dilate your pupils, take in more light
but more of a tunnel vision experience because you're focusing in
on what might be threatening you, right, and you don't need to have a
lot of saliva flow so we shut that off, accelerate your heart beat so you can
get more oxygen
more quickly to the muscles, dilates your bronchi so you can take in more oxygen
inhibits peristalsis and secretions in the
intestines cause you don't need to be digesting food right now. In fact, you
might even feel sort of a butterfly in the stomach
sensation, right, as you get that shut down.
Converting glycogen to glucose to creating adrenaline and noradrenaline
and somebody else had a question about adrenaline. That's epinephrine
is another name for it, right, epinephrine, norepinephrine,
or adrenaline, noradrenaline, same stuff. Inhibits bladder contraction
and that allows you to focus in on dealing with the threat
for a short period of time. You'll be tweaked out, ready to fight,
or to flight, run away or fight as hard as you can but as soon as the threat is past the
parasympathetic will take back over control
and return you to baseline automatic functioning so that you breathe
and you digest and all that other important stuff so we talked about the
central nervous system. I was just going to point you back at this, we've already
covered this, so I'm not going to
hang on it too long. You've got your hind brain that we share with reptiles,
we got our midbrain and we got our forebrain and that's a large section, many parts. We got
our
thalamus and we got our hypothalamus with our four F's which are really
absolutely essential to survival and procreation.
That's what we're talking about right there, right? To survive you have to eat,
right? So feeding is important. You have to fight
or flee if you are faced with a threat and you have to engage in
reproduction
to progenerate the species. So we all have these biological drives within us.
You don't go, I don't think I'll be hungry today.
You are hungry because that's an automatic
natural reaction. Those kind of things are monitored by the
hypothalamus and then we had the limbic system that we started talking about. I
believe we got stopped about right there.
Separate but connected structures throughout the brain which help regulate
memory. They also help regulate emotion.
They also help regulate arousal and thus motivation.
So there's multiple structures in the brain but you now know
with interneurons, these are connected to one another.
So they have neurons originating within these sections that project out into
other sections that they are related to in terms of function and they
communicate with one another
and they do so so fast that you can't even perceive it. It just feels like it's
automatic. But it isn't. There's a process that goes
on internally that can be inhibited by drugs,
could be inhibited by damage to the tissue, either through an external
insult to the brain like a crash or a blow to the head
or a fall, or an internal insult, which would be something along the lines of a stroke
causing lesions or tumors growing and pressing on areas of the brain.
All those areas have to be in their ideal shape to function well and
integrate with one another.
So this limbic system; we have the hippocampus which we'll talk more about
when we get into the chapter on memory helping us with formations of new
memories.
So if you've seen that movie 50 First Dates where the Drew Barrymore character
can't remember meeting
the Adam Sandler character, and it just looks crazy.
Right? That's not real. Yeah, it can be real. It depends.
It would be hard to sustain a deep brain injury like that but if you broke a blood
vessel you certainly could.
If you had a stroke, you certainly could. If you had a lesion in
terms of a tumor pressing on and killing off that
that tissue, you certainly could and if you don't have a hippocampus,
you don't remember anything new. It's required
for us to form new memories. We just do that all day every day
so we don't put our minds to what's going on and that's where I say practical
significance,
you're not going to run into hippocampal damage much in your life or the lives of your
family and friends, thank goodness,
but when you're thinking about your ability to remember things,
you're talking about the hippocampus and forming new memories,
and stress, prolonged chronic stress and prolonged chronic anxiety
can actually inhibit that because you can get neuronal death in the
hippocampal region
from chronic exposure to glucocorticoids and that is
something we will talk about in that anxiety stress seminar.
The amygdala facilitates learning fear responses. When we get into the learning chapter
one of the most important chapters from my point of view, you're going to start looking at
classical conditioning and looking at learning there,
we start to see mechanisms that facilitate learning
or inhibit learning, which we'll talk about in the memory chapter,
but when you have a fearful experience, when you have sickness,
pain, or fear you only need one time to be exposed to the stimuli to
learn to avoid them, right? You get instant learning.
Most things you've got to expose yourself to time and time again
or do time and time again. When you're studying for a test
it helps if you will do that time and time again, right? It is work
to acquire this information and remember it. But how many times do you have to touch a
hot stove to learn that information?
One time and it creates an enduring memory that seems to be facilitated by the
amygdala.
So when we have those powerful negative emotional experiences
we get a thing called flashbulb memory sometimes where you have a pretty vivid
recollection
of what occurred at the moment that trauma happened to you.
Then we've got the self-stimulation centers, the pleasure centers where animal subjects, and this
is looking at ESB, electrical stimulation of the brain,
animal subjects will continually stimulate this area of their brain
if at all possible. It seems to be heavily involved with dopamine regulation
which I said the other day, technically,
the only thing you enjoy is dopamine and serotonin. Those are the neuro
transmitters
most centrally involved with pleasure, although other ones are involved,
An area of the brain that seems to be centered in what we call a self-
stimulation center, why is it called that?
Because what we would see with animal models, using rats
and surgically implanting a little electrode into that area of their brain
connecting it to a lever, they would press that lever and
wooooo - have them a little mental orgasm.
You all know why people do cocaine and things like that? Because when they do it they go
wooooooooo
woooo - they have them a little mental orgasm. They just
lights them up, right, and it's the same area of the brain involved.
It's the same area of the brain involved. So what you would see was a little rat
would push that lever
and push that lever and push that lever to the exclusion of
eating until it got so exhausted it would just pass out and sleep
and as soon as it got back up it was right back to pushing that lever. Animal model of
addiction,
right? What you see as the analog in humans
is the use of certain psychoactive substances
that produce that really intense high or really intense pleasure
has a high potential for addiction. Now when we get into the learning chapter we'll see
how that wanes over time and it's replaced by other processes
that have implications for why treatment of addictions is so
damn difficult, because it's not just people's willpower.
If it was, people would get better cause most people who are addicted,
losing their families, losing their jobs, losing their self-esteem
and all that other stuff are not enjoying that ride. They would like to
change it if they could.
So it's an easy kind of thing - oh well, they just don't want to be different.
That's not exactly the case.