0:03 [Music]
0:08 it's time to cover the neural basis of
0:14 behavior okay so our brain and the rest
0:16 of our nervous system consists of
0:18 neurons we've got it
0:19 just like with genetics and we broke it
0:21 down to the most basic unit we've got to
0:23 break it down to the most basic unit
0:29 here and that's the neuron the neuron is
0:31 this tiny information processing system
0:33 with thousands of connections for
0:35 receiving and sending electrochemical
0:37 signals to other neurons it's a cell
0:40 when it comes down to it the neuron is a
0:45 cell a group of neurons is called a
0:48 nerve so we're gonna go through all the
0:49 parts of the neuron so y'all are gonna
0:52 understand truly what it is but it's
0:54 this specialized cell designed to
0:57 transmit information to nerve cells
1:01 muscle or gland cells okay some
1:03 different stats written down each body
1:07 may have as many as one trillion neurons
1:09 think y'all there's seven point one two
1:11 five last I load seven point one two
1:15 five billion people in the world yeah
1:18 the body may have as many as one
1:23 trillion neurons that's way more the
1:27 brain has 100 billion neurons each
1:32 neuron has one thousand to tens of to
1:36 ten thousand synapses 100 to 1,000
1:40 trillion synapses in your brain total
1:43 this is really cool to think of ok the
1:44 people in the world versus how many
1:46 neurons we have because you can kind of
1:48 look at the body as a microsystem
1:52 of the world so zoom out from Russia you
1:54 get really high up in outer space and
1:56 look down on us and then we become just
2:01 as small as a neuron but there's less of us
2:08 [Music]
2:11 somewhere in the universe is a small
2:13 blue planet the third Rock from a star
2:16 called the Sun just one of billions of
2:18 stars in a spiral galaxy known as the
2:21 Milky Way but where in the universe is
2:26 the Milky Way a team of scientists
2:28 gather data on more than 8,000 of the
2:32 galaxies that surround us they mapped
2:34 each galaxies position and movement in
2:38 space and for the first time they've
2:39 shown that the Milky Way is part of a
2:42 much larger system of galaxies a super
2:45 cluster that they have named Laniakea
2:48 the Milky Way is nested in the furthest
2:50 reaches of this structure on the outskirts
2:51 outskirts [Music]
2:58 the entire universe can be seen as an
3:00 intricate network of galaxies a cosmic
3:03 web some areas are almost empty dark
3:06 voids others are densely packed with
3:08 galaxies in regions known as super clusters
3:09 clusters [Music]
3:18 oh let's put its the basic building
3:25 block of the nervous system okay we've
3:29 got to talk about glial cells glial
3:32 cells hold and support and hold neurons
3:38 in place 90% of the brains total cells
3:43 are glial cells they supply nutrients
3:49 and oxygen perform cleanup tasks and
3:52 insulate one neuron from another so that
3:56 their neural messages are not scrambled
3:59 so basically they take care of the
4:03 neurons right we could say that and so
4:06 y'all want to know what I call them I
4:10 call them the neurons parents hi mom and dad
4:12 dad
4:16 dis your place no no no no no no no I
4:18 live with my mom yeah
4:21 you hungry hey mom we get some meatloaf
4:24 doesn't this make sense they support the
4:25 neurons they hold the neurons in place
4:28 they supply nutrients and oxygen they
4:31 perform cleanup tasks they insulate one
4:33 neuron from the other so that they are
4:35 and messages do not get scrambled they
4:37 keep you separated from your brother or
4:39 sister when you're fighting so they also
4:44 play a small role now a small role in
4:48 nervous system communication the star of
4:51 the communication show though is the
4:54 neuron this is pretty cool no two
4:57 neurons are alike so I just said oh if
4:59 we zoomed up in outer space and got this
5:02 above picture of us and we're almost
5:05 smaller's neurons well
5:08 no two of us are exactly alike no two
5:10 neurons are exactly alike they're like
5:14 snowflakes they although share some
5:17 basic features and we're gonna go
5:19 through those but mainly they share they
5:21 have dendrites they have a cell body and
5:23 they have an axon we said several times
5:26 that they speak in a type of electrical
5:29 and chemical language so we're going to
5:30 talk about how that is so
5:33 let's look at the parts of the neuron
5:36 well let's start off with the dendrites
5:39 these little tentacle type things these
5:41 are the branching fibers of neurons that
5:44 receive neural impulses from other
5:47 neurons and convey impulses towards the
5:50 cell body so how do I remember the parts
5:51 of the neuron
5:56 well I pretend I'm in the room these are
6:02 my dendrites these are my branching
6:04 fibers and I think of myself kind of
6:06 like an alien and I say receiving
6:09 receiving or receiving receiving this
6:11 feels even sillier than doing it in the
6:17 classroom receiving receiving receiving
6:19 receiving I'm receiving information
6:21 you'd think of it like antennas a top of
6:24 your head and antennae receiving
6:28 information also how I think about it
6:30 then is I think well if they're my
6:32 fingers here what's fingers in Spanish
6:35 Davis right so I think dedos dendrites
6:38 receiving receiving receiving so the
6:40 next part we need to learn is the cell
6:43 body and that's gonna be kind of this
6:46 right here the part of the neuron that
6:49 contains the cell nucleus and other
6:50 structures at health and neuron carry
6:53 out its functions it's also known as the
6:58 soma pourtant word to realize what that
7:02 means soma means body I don't know if
7:05 anybody's been to that pyjama store in
7:09 the mall called soma oh of course
7:12 receiving receiving receiving my cell
7:16 body contains the nucleus my brain the
7:19 nucleus is like the brain what's next
7:24 the axon this is the axon the axon is a
7:26 long tube-like structure that conveys
7:29 impulses away from the neuron cell body
7:31 towards other neurons or to muscles or glands
7:32 glands
7:44 now the myelin she
7:47 it's like fatty insulation it covers the
7:50 axon of this of the neurons or some
7:53 neurons to insulate and help speed up
7:56 neural impulses if blankets the axon
7:59 instead of saying it's the fat on high
8:03 poly what I go with it's my clothes this
8:06 is my insulation and the main thing here
8:07 is that this myelin sheath help speed up
8:10 neural impulses so I think if I'm stuck
8:13 outside in a blizzard and I don't have
8:15 any clothes or I don't have good warm
8:17 clothes I only have one layer I'm gonna
8:34 end up frozen I'm frozen all right have
8:37 a myelin sheets of insulation now we are
8:44 all warm and toasty and guess what I'm
8:47 just running to generate more heat it's
8:49 a safety so your clothing is that warm
8:53 insulation okay so neural impulses move
8:57 much more slowly than electricity loose
8:59 through a wire the neural impulse
9:01 travels along a bear axon without any
9:03 myelin sheath had only about 10 meters
9:06 per second electricity just to put in
9:08 perspective moves at 36 million meters
9:12 per second 10 meters per second versus
9:14 36 million meters per second in an
9:18 myelinated axon the neural impulse moves
9:21 about ten times as faster than a fare
9:25 axon so it speeds it way up it's really
9:27 interesting if you look at the impact of
9:29 the myelin sheath of research research
9:31 shows that social isolation during the
9:33 early weeks and months of life has
9:36 occurs for babies who are in orphanages
9:40 or who are neglected prevent cells from
9:42 producing the right amount of myelin
9:45 which leads to long-term problems in
9:49 cognitive functioning so here I see this
9:52 really interesting combination of the
9:56 body and nature and nurture the myelin sheath
9:56 sheath
10:00 doesn't properly develop when there's
10:02 social isolation in the early weeks and
10:05 months of life and that leads to
10:14 terminal buttons these forum junctions
10:17 with other cells and release chemicals
10:20 called neurotransmitters you know we're
10:21 interested in neurotransmitters in
10:24 psychology because we talk about things
10:25 we've researched things like serotonin
10:27 we can look at depression as being
10:29 caused by not having enough serotonin
10:31 and so you can take something like a
10:34 Sarah and SSRI serotonin reuptake
10:36 inhibitor selective serotonin reuptake
10:38 inhibitor we're gonna get some more of
10:41 that but what are the terminal buttons I
10:44 think that they're my toes so I'm not
10:46 gonna take off switch to those and show
10:50 my toes but they're the terminal buttons
10:52 you can think about as little tiny
10:56 buttons on the end of your feet and it's
10:58 from there that the little
11:00 neurotransmitters are going to jump now
11:03 whenever a neuron connects to another
11:09 neuron there is a synaptic gap so show
11:12 on the screen say we wanted to draw
11:13 another neuron here these are the
11:16 dendrites and really they're synapses
11:19 all over and they're on not just on the
11:21 dendrite but we're trying to keep things
11:24 real simple and so it's important to
11:26 know that right here they're not
11:29 actually touching there's a synaptic gap
11:32 or sometimes refer to a synaptic cleft
11:35 this is less than five millionths of a
11:38 centimeter and so it's this tiny tiny
11:41 opening between the sending sending
11:54 neuron and the receiving neuron okay so
11:58 I'm a neuron receiving receiving
12:00 receiving receiving information comes in
12:03 it travels down it actually travels down
12:07 the axon almost like a wave in a sports
12:09 stadium we'll talk about that if I could
12:12 do a body roll that's you so receiving
12:15 and receiving receiving body ball down
12:18 gets down to the bottom down to the
12:21 terminal buttons and then say we are
12:23 going to connect form a nerve
12:27 well somebody in the class would be the
12:31 next person so your fingers we'd have to
12:35 touch my toes thank you don't want to do
12:37 that you don't want to touch my toes not
12:39 that my toes are bad or anything but
12:41 germs you know so you don't want to
12:42 touch my toes so instead we leave the
12:45 tiniest space possible but even though
12:49 we leave that tiny tiny space the germs
12:52 are going to jump the gap so receiving
12:54 receiving receiving information coming
12:56 down travel by the body roll goes down
12:59 to the bottom the germs
13:01 jump the gap you receive I'm receiving
13:04 receiving receiving information down the
13:06 next person you connected to the germs
13:12 jumped the gap so this kind of body roll
13:14 thing that I mentioned
13:17 that's called an action potential this
13:21 is the communication within a neuron so
13:23 that germ that jumps the gap that's the
13:25 neurotransmitter remember it's
13:27 neurotransmitter that's a chemical
13:30 within communication which in the neuron
13:34 is electrical and it's called an action
13:36 potential it's the message that moves
13:39 along the axon in the form of a Norton
13:42 or neural impulse action potential has
13:44 to do with positive and negative
13:48 polarization over although it moves like
13:51 a wave in a football stadium [Applause]
14:09 so this wave or this body roll this
14:12 action potential has to do with sodium
14:15 ions and potassium ions and they move
14:19 into and out of the axon cut causing
14:22 this electrical change sodium ions and
14:24 potassium ions moving into and out of
14:28 the axon cause electrical changes so
14:30 typically when a neuron is resting
14:31 meaning it's not transmitting
14:33 information these tiny gates all over
14:35 the membrane called ion channels are
14:38 closed and a slight negative charge is
14:40 present along the inside of the cell
14:42 membrane so typically the axon slightly
14:44 negative on the inside and it's positive
14:49 on the outside so how does an action
14:51 potential happen well one of the doors
14:55 opens letting positive in positive and
14:57 negative are opposites attract are going
14:58 to run towards each other as soon as
15:00 they get a chance so the positive is
15:03 going to run in negatives going to run
15:05 out and there's a series of opening and
15:08 closing basically the little gates that
15:21 [Applause] [Music]
15:22 [Music] [Applause]
15:26 [Applause]
15:30 so all we do we like [Music]
15:45 it's a series of opening and closing
15:49 basically the little gates causes this
15:53 kind of electrical movement electrical
15:58 charge to move through the axon now
16:01 where's this all-or-nothing principle
16:03 basically once an electrical impulse
16:06 reaches a certain level of intensity it
16:08 fires and it moves all the way down the
16:10 axon without losing any difference to
16:13 intensity so we also look at
16:16 neurotransmitters neurotransmitters are
16:17 gonna jump the gap and they're either
16:20 going to excite the nerve the receiving
16:21 neuron or they're gonna inhibit the
16:22 receiving neuron
16:26 if the dendrite if the receiving axon
16:30 receives enough of the message that side
16:32 Ettore message then the neuron will fire
16:35 it either fires or it doesn't fire
16:36 that's called the all-or-nothing
16:39 principle it fires all moving all the
16:41 way down the axon without losing any
16:44 intensity so it's kind of like a gun a
16:46 gun either fires or doesn't fire it
16:49 doesn't kind of buy them and yet this
16:51 may be confusing cuz you can say well we
16:53 have I don't know varying levels of
16:56 sensation pressure for example you can
16:58 either kind of tiny press a really press
17:02 let varying levels of intensity this
17:05 doesn't have to do with how much oh like
17:07 it acts the the neurons kind of firing
17:11 kind of not nope it has to do with how
17:13 many neurons are fine firing and the
17:16 frequency of firing so that's within a
17:21 neuron it's electrical when I mentioned
17:23 and I keep mentioning neurotransmitters
17:26 these are chemical so within the neuron
17:28 mess the neuron messages to travel
17:32 electrically between neurons messages
17:35 travel across the synaptic gap via
17:36 chemicals called neurotransmitters
17:40 messages travel chemically between
17:42 neurons ok so when you go through some
17:45 different types of neurotransmitters and
17:48 their effects and I think I'm gonna post
17:52 a video that kind of explains this
17:54 because the guy does a pretty great job
17:58 so if you're watching out for that but
18:02 just really quickly we know serotonin
18:05 right and we've talked about a serotonin
18:08 reuptake inhibitor what a serotonin
18:11 reuptake inhibitor is going to do is
18:14 it's going to block the sending neuron
18:16 from taking back its neurotransmitters
18:19 so say this is the sending neuron and
18:26 this is the receiving neuron while
18:28 neurotransmitters are going to typically
18:43 receiving neuron some receptor sites but
18:46 they just go over they latch into and
18:49 they trigger a response and then they go
18:55 back reuptake what a reuptake inhibitor
19:04 it blocks a sending neuron from taking
19:08 back up that set that serotonin so then
19:10 it just stays within this gap and it can
19:14 keep activating the neuron or carrying
19:17 out whatever its purpose is so that's
19:19 what a rehab tech inhibitor is it's
19:22 stopping the reuptake leaving an excess
19:26 of serotonin in the gap so we know
19:29 serotonin has to do with things like
19:32 mood we know for one has to do but it
19:34 also has to do with sleep and dreaming
19:36 and appetite dopamine is an interesting
19:41 one dopamine has to do with motor
19:46 control but it also has to do with
19:48 pleasure areas of the brain with
19:50 motivation with reward areas of the
19:54 brain but when we found that people with
19:57 too little dopamine 10 we see this
20:00 related to Parkinson's disease whereas
20:02 too much dopamine is related to
20:06 schizophrenia I want to explain the
20:08 and I'm gonna go ahead and upload this
20:14 video from this other guy I really like
20:20 his example of agonist versus antagonist
20:24 neurotransmitters or drugs so look for
20:26 this posting because this is required
20:29 lecture content agonist versus antagonist
20:30 antagonist
20:33 I'll post two videos one where he talks
20:35 more about different neurotransmitters
20:36 and the other where he talks about a
20:43 venous versus an antagonist it's
20:45 important to know that neurotransmitters
20:49 are locked into the receptor site like a
20:53 lock into a key this is pretty crazy the
20:54 shape of the neurotransmitter has to
20:58 match the shape of the receptor site in
21:01 order for it to lock in and for it
21:05 either to excite or inhibit the neuron
21:11 okay so that's about the neuron the most
21:15 basic structure of the nervous system we
21:18 need to now mention the endocrine system
21:20 pretty quickly we don't spend as much
21:23 time on the endocrine system but it's
21:26 important the internet system is a
21:28 network of glands located throughout the
21:29 body that manufacture and secrete
21:35 hormones into the bloodstream so think
21:37 puberty where you have this influx or
21:57 [Music]
22:00 truth is no one quite knew what was wrong
22:00 wrong
22:03 most times a person grows up gradually
22:16 where's daddy
22:17 well he just look what's wrong I'm
22:19 hemorrhaging what do you mean you're
22:22 hemorrhaging and I don't need your help
22:28 did this happen in the bathroom told you
22:30 it's okay
22:31 come on upstairs we have to have a
22:37 little talk it's not fair nothing
22:44 happens to boys hi Berta can you come
22:49 out and please it's real hot maybe we
22:56 can go swimming no yeah here and don't
23:06 so hormone is a chemical messenger
23:09 manufactures in secreted by the enter
23:10 compliance which circulate in the blood
23:13 soon to produce bodily changes or
23:16 maintain normal bodily functions all
23:18 kinds of things are impacted by hormones
23:20 mood arousal circadian rhythms
23:25 metabolism immune system they can signal
23:28 growth help with reproduction attraction
23:32 appetite aggression hormones can have a
23:36 drastic influence on the body so all of
23:39 this the endocrine system is regulating
23:41 long term bodily processes and controls
23:44 the body's response to emergencies as
23:47 well so I'll post a picture here buddy
23:51 of the different glands we have the
23:53 pituitary gland the thyroid gland the
23:56 ovaries or testes a pair of thyroid the
23:59 adrenal the pancreas the pituitary gland
24:01 is considered the master gland because
24:04 it kind of controls everything else
24:07 almost all of its hormones direct the
24:11 activity of the other glands the
24:13 pituitary glands though has its own
24:17 master the hypothalamus
24:20 so it's important that we compare while
24:24 the endocrine system compared to the
24:27 nervous system because we know we have
24:29 two chemical messengers here while we
24:32 have neurotransmitters and we have
24:36 hormones you can think of them like
24:39 emails with the nervous system and
24:42 neurotransmitters these are like
24:46 individual emails we send emails to
24:49 particular people so if I sends an email
24:53 to one of you guys only you would get it
24:58 nobody else would over here hormones
25:01 instead are like global emails mass
25:04 emails when I send an email to the
25:07 entire class or an announcement through
25:13 canvas everyone hears everyone is notified
25:15 notified
25:17 so hormones are carried by the blood
25:19 throughout the body to any cell that
25:22 will listen it's like this mass email
25:23 that just floods when you hear about
25:26 hormones you hear you're flooded your
25:28 system is flooded with this hormone
25:30 every everyone hears it
25:33 so you're flooded and it also lingers it
25:36 can take some time to for example simmer
25:39 down after its screen moments of fright
25:43 or anger testosterone is a hormone that
25:45 maybe a lot of people have been hearing
25:47 about you know this idea of low tea high
25:51 tea there's a study that I read so they
25:55 had a bunch of people rolled dice in
25:57 private and then they had to report
26:00 their numbers and they received money
26:03 based on the results so if you're a high
26:05 roller you've got cash
26:07 thanks down and this was really
26:08 surprising because when you think about
26:10 testosterone you kind of think about
26:14 these big beefy guys that are very manly
26:16 and they're going to be aggressive and
26:24 but what they found was that high levels
26:28 of testosterone you actually reported
26:30 self-reported the numbers more honestly
26:34 so it fosters in a way they found social
26:37 behavior and honest interaction which
26:38 was a really big surprise because you
26:40 think someone who has too much
26:42 testosterone it's not going to be
26:44 pro-social and so what you start to
26:49 wonder is maybe that lying dishonesty is
26:53 a result of insecurity or feeling bad
26:56 and the more testosterone you have the
26:58 more confident you are maybe that leads
27:02 you to being more honest more bolder
27:04 regardless hormones influence the way
27:06 you act the way you and the way you have
27:09 influences your hormones so it's really
27:13 interesting it's bi-directional cortisol
27:15 is a stress hormone that we're going to
27:17 talk about later on adrenaline is a
27:20 hormone I think adrenaline is the
27:22 confusing one that's both a hormone and
27:29 okay I think that's pretty good
27:33 introduction to the neuron
27:35 neurotransmitters and then the endocrine
27:39 system as well thanks for watching y'all [Music]
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