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BIOL 2301 Human Anatomy & Physiology I - BIOL2301_lecture12_0623
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00:03 OK. I think it's working. right. Yes, it is.
00:06 . Ok. Um All right. just a reminder we have the test
00:13 Tuesday, not on Monday. Um , uh use your weekend to kind
00:19 do as much studying as you can make your life easier for Monday night
00:23 really kind of the way I'd put . Um, you know, so
00:27 , we're gonna have another lecture that lecture on Monday goes on the
00:31 because it's four units and then a . So prepare accordingly. Yeah,
00:37 sucks. I don't like the way set it up, but that's just
00:39 way it's set up. Um, we're gonna do today. Um There's
00:46 stuff that's just really kind of light easy. The first stuff that we're
00:48 to be dealing with, we're going be looking at the different types of
00:52 , the glial cells. Uh then going to kind of look at how
00:55 brain kind of forms itself and then we're gonna do is we're going to
00:58 gears and kind of move into the cord and its general structures. What
01:03 gonna notice is very similar to what already talked about gray and white
01:07 And then what we're gonna do is going to start moving into the peripheral
01:10 system to look at gene generic All right. So the idea is
01:15 understand uh the organization of the peripheral system via the spinal nerves. And
01:20 we're going to look at the different , there's four plexuses, we'll be
01:23 at them and their structure as Ok. So we kind of are
01:28 around a lot in this unit and just kind of the way it
01:32 Um So we've talked about neurons And so what we're going to do
01:38 we're going to focus here on the cells. But I just want to
01:41 out this one thing is that remember neuron, it's the excitable cell that
01:45 responsible for transmitting the electrical signal. one of the types of cells,
01:50 neurons that you're going to see quite bit. So we kind of looked
01:53 this one. This is how we've seen these multi polar neurons and
01:59 use this because these are all over place. But in the central nervous
02:03 , this is the type of multipolar that you see most often. It's
02:09 a pyramid cell. And you can guess why it's called a pyramid cell
02:14 it was discovered in Egypt, No, no, no, it's
02:19 pyramid shape here. You, you it right. It's like, why
02:22 they call it an astrocyte because it discovered in Houston? No star
02:30 All right. Now, you can it has a cone shaped soma,
02:34 has a single axon. It's it's not always easy to find
02:38 I mean, you have to kind be a neurologist or at least be
02:41 , very familiar with the anatomy to of, or histology to kind of
02:45 . But that right, there would the axon all the rest of these
02:47 , even though they're elongate are And so you can see there's just
02:51 dendrites and these are all throughout the . And so, you know,
02:55 going to look at some sections, sections but different regions of the
02:58 And you might see this term pop . And so the reason I'm showing
03:02 this now is not because I'm going say what is a pyramid cell.
03:05 so that when we look at other and you see the pyramid cells
03:08 you're not going, what is Is this some sort of weird,
03:11 thing that I need to know. just a neuron that has been identified
03:15 on its shape. OK. It's like what we've been looking at
03:20 The ones that we'll see primarily are be the ones that are gonna be
03:22 in cognition when we start looking at um the central nervous system specifically,
03:28 when we start looking at the what we're gonna focus on today
03:34 or at least the first part of supporting cells. All right. So
03:36 are the glial cells. So you see this term. It's one of
03:40 weird words. And if you read for the first time you'd probably just
03:43 it's neuroglia, but it's pronounced neuroglia reasons, right. Probably some British
03:49 said it and you know how they weird accents on stuff, right?
03:53 the neuroglia, the glial cells, the, the support cells of the
03:57 system and there are six basic All right, we're gonna have four
04:02 are found in the central nervous Two that are found in the peripheral
04:05 system. The two that are found the peripheral nervous system have similar functionalities
04:10 the two others that are in the but because of where they're located and
04:14 they're different. OK. So that's they're identified uh separately right now.
04:21 do not transmit electrical signals. Their is to support the neuron, they
04:28 neurons roughly 10 to 1. Uh example I always use in, in
04:32 other classes, like think about a team or a soccer team. Really
04:36 football team is probably easier. It's if you think of the most important
04:39 on a football team, everyone kind goes, oh, it's the
04:42 I mean, that way he's the that we make the big deal
04:44 right. But the quarterback can't do unless he has a line, can't
04:48 anything unless he has receivers, can't anything unless he has running backs to
04:52 the ball off to. All So the quarterback is awesome because of
04:57 the other players on the field and neuron is awesome because of all the
05:01 cells that support it. Right. couldn't do what it does without all
05:06 different types of glial cells. So terms of the different types you can
05:11 here here, central nervous system, have astrocytes, we have the ependymal
05:15 , which you've already kind of talked a little bit. We have the
05:18 , which we mentioned when we talked myelin and then we have the microglia
05:22 looks like microglia. But again, a weird accident thingy. So
05:26 all right, we're going to go these and then out in the peripheral
05:30 system, we have the satellite cells the Schwan cells. All right.
05:34 are also called neuro limo sites. you'll probably see that term more frequently
05:39 than so now to um create an , there is a progenitor cell,
05:49 right. So like a stem cell it gives rise to um different types
05:55 , of these um uh glial So it's called oligodendrocyte progenitor cell,
06:00 it can give rise to all sorts different types of cells here.
06:04 these are found throughout the central nervous . What they do is they kind
06:08 follow a signal. So if they're their premature form, like as this
06:15 they put out growth cones, what they're doing is they're kind of
06:18 them, they're looking for chemical signals that chemical signal will direct them to
06:22 they need to go. And then they finally arrive to where they need
06:24 go, that's going to stimulate them divide multiply and differentiate so that you
06:29 things like the alloy. All So typically you're going to be going
06:33 damaged areas. So, you most of this stuff is going to
06:36 developed very early on. But if are developing your brain or you
06:41 if there's damage that happens to these cells exist to do the work
06:46 repair or to replace is really the that I'm looking for here. So
06:52 are the different cells? What are different types that we can come up
06:56 ? Well, the Ogaden side, is the uh support cell that produces
07:01 myelin. All right. Oligo means , if you, if you never
07:05 , it's, it's, it's less poly, but more than than
07:09 All right. So Oligo is some between two and infinite. All
07:15 And so you can see here, my cell body and you can see
07:19 it has these processes that come out there's anywhere up to 20 to 50
07:25 processes that will extend from an And what they'll do is they'll reach
07:30 and find an axon. And what do is they'll wrap themselves around that
07:35 creating that myelin sheath. All So they can myelinate up to 50
07:39 axons. That's hence the term all site. All right. Uh They
07:45 also inhibit a neuron's ability to In other words, what they're doing
07:49 they're telling the neurons your job is just signal, don't try to multiply
07:53 divide it basically represses that activity. And it can help control neuronal
08:00 So it's not just myelin, there's things that it does, but for
08:04 purposes today, myelin, OK. nervous system, myelin, the neuro
08:11 site or Schwan cell is in the nervous system. And it's very similar
08:15 the oligodendrocyte in terms of function, terms of structure, very different.
08:21 they do is they migrate and find axons of the cells and then they
08:25 themselves individually. So that's an a limo site. That's a neuro limo
08:30 , that's a neuro limo site. one of those is its own individual
08:33 . And you can kind of see it's done is it's taken, it's
08:36 itself um multiple times around the cell then it sits there and it now
08:41 as that ion sheath. All So very, very different in terms
08:47 its structure. Each individual cell creates single sheath. So you'll have,
08:53 you follow an axon, you'll see hundreds to several 1000 of these neural
08:57 sites. Now, what's interesting is I damage a neuron, so let's
09:02 I damage down here. What will is that the neuron will remove everything
09:08 and actually, it will kind of back a little bit and the neuro
09:11 sites stay in place and they release to tell that neuron where to
09:18 And so it will grow in the direction as where it is and then
09:21 re wrap themselves around that new but the rate of repair is
09:27 very slow. So sometimes they kind move on if the thing doesn't show
09:30 in time, it's like, oh done and so it's not perfect.
09:36 right. So neuro LeMay peripheral nervous , myelin, so far two my
09:44 . Now we move away from We go to the Astros site,
09:46 one that was discovered in Houston. . Fine. All right, star
09:52 . It's the most abundant uh glial . Now this has multiple functions.
09:59 right. One of the things that can do is that you can think
10:01 terms of it is the connective tissue of the brain. In other
10:06 it creates the scaffolding on which the cells actually direct you can see
10:12 this green thing is supposed to be astrocyte. All right, blue things
10:17 supposed to be the neurons. And it's done is it's basically sent out
10:20 these processes and it's created a network it's holding things into place and everything
10:26 it is being held in place by astrocyte. We saw that it wrapped
10:31 around the capillaries, creating part of blood brain barrier. It actually creates
10:38 to ensure that the neurons are actually that you can actually maintain synapses.
10:46 right, it does all these crazy to ensure that the brain structure is
10:53 it's supposed to be, it controls chemical environment by wrapping up the
11:00 It helps determine what goes in and goes out of the brain extracellular
11:06 By wrapping the synapses, it determines gets destroyed and what gets kept
11:12 It is what delivers the nutrients to neurons by basically creating that boundary.
11:20 controls the ion concentrations. And so brain extracellular fluid is dependent upon the
11:30 of the astrocyte to ensure that it kind of this standard environment through which
11:36 neurons can actually work can play a in repairing damaged cells. It acts
11:42 scar tissue, which we mentioned I told you about the student with
11:45 pickax in the head. Um it stimulate other cells like the oligodendrocytes.
11:54 , astrocytes are kind of this catchall connective tissue like cell, it is
12:01 connective tissue, it is nervous but it behaves in kind of the
12:05 way creating the environment of the uh nervous system. The ependymal cells we
12:15 when we talked about the cerebral spinal , that's their job is to produce
12:19 spinal fluid, they're found in the , right? Those internal cavities they
12:25 ciliated. So here's the cartoon, can see the cylia if you look
12:29 , very closely at the picture, can see the silly on the
12:32 This is what helps that beating to move this uh spinal fluid as it's
12:37 made, they're at um attached to astrocytes that underlie them. So these
12:43 the epidermal cells, these are going be the astrocytes holding things in
12:48 Um So the key thing here is spinal fluid, the microglia are the
12:59 ones. So they do all sorts interesting. They make up a uh
13:05 10 to 15% of the cells in central nervous system. And their job
13:10 to kind of just sit around and nothing unless they are activated. And
13:14 they're activated, what they do is act as resident macrophages. So they're
13:18 of the immune cell of the central system. All right. Now,
13:23 not all they do. They can divide and become um responsible for other
13:29 as well. But what we've discovered that they're like monocytes, a monocyte
13:35 an immature macrophage and they sit around they do nothing, basically just releasing
13:42 factors to make sure all the cells happy and everything is going hunky
13:45 But when damage occurs, so one the interesting, I went to this
13:50 once and it was talking about macrophages it was all about, um,
13:56 . And they show that when a occurs, you know, you damage
14:01 sorts of cells and these things go bonkers and they start migrating all over
14:05 brain, destroying the tissue that has damaged. Their job is to behave
14:11 that destroy and deal with the damaged so that you don't harm brain
14:20 So they'll deal with damaged neurons, damage, deal with damaged neuroglia if
14:28 get something infectious beyond the blood brain , which you hope you never get
14:33 the immune system is not allowed past blood brain barrier. All right.
14:38 these cells behave as if they are immune cells. All right. And
14:44 they can present antigen which makes more when you know about the immune
14:48 All right. So their job think behave as the immune system.
14:56 there's a cell that I don't have slide for. So I'm gonna go
15:00 a slide too. All right, going here to aides. The satellite
15:06 is like the astrocyte of the peripheral system. All right. Now,
15:13 all sorts of function here. But wanna go back to the picture.
15:15 wanna just kind of show you where is. All right. So let's
15:19 back, go back, go go back there. We are,
15:22 can see here. So, what looking at in this picture here,
15:26 little things that are flat and look . Those are supposed to be the
15:29 cells. And really what they do just like the astrocytes, they are
15:34 for hanging around the cell bodies of , of the neurons. That's what
15:40 is. So these are, that's axon, we'll learn about this weird
15:44 when we talk about the peripheral nervous . But what we have here is
15:48 have a series of satellite cells and provide all the nutrients they are there
15:51 maintain the relationships between the cells and all the things that the astrocytes
15:56 But in the peripheral nervous system. . So the easy way to remember
16:01 astro is stars or you can think being in space city or whatever it
16:07 . All right, it makes it for us and satellites are found in
16:12 and so they are related. So do the same kind of things.
16:16 how I remember it. All I don't know why I don't have
16:19 slide. I don't think I've ever a slide. I think I'm a
16:23 man who knows. So that gets through those six different cells. Do
16:30 cover all six cells? Yeah. . So here's where we kind of
16:37 kind of jump around and do So what is the whole purpose of
16:41 nervous system? Well, everything in two pictures here kind of represent what
16:45 nervous system is responsible for. All . So remember we have a nervous
16:50 that's divided into two parts. What central, what is peripheral? So
16:53 we talk about the peripheral, what gonna do is we're gonna receive signals
16:56 we're gonna send signals. All And where are we receiving signals uh
17:01 where we are, where we receiving signals and sending them to or sending
17:04 to the central nervous system for processing then once we process, we're gonna
17:09 out in a way so that we other parts of the body to do
17:13 . All right. So that's integration what the central nervous system is
17:18 And when we integrate, what does mean? Well, it means we
17:20 store stuff in a memory, What else does it mean? It
17:23 we can do something about it. I take my keys and throw them
17:26 you, what do you do? do you do? You catch them
17:30 if you want to, you can out of the way. There's a
17:33 of choices here, right? You catch them and throw them back at
17:36 . There are plenty of actions that can perform as in response to some
17:41 of process or you can just let hit you in the face,
17:46 You can ignore action. Have have you done that? Have
17:49 did you have a roommate that, talks to you and you just kind
17:51 not listen to him. Yeah. . Or a parent clean your
17:57 OK. I'm just ignoring, So you can do all sorts of
18:04 with regard to, with that All right, that you're receiving.
18:09 so the integration and the processing all stuff we when we receive, we're
18:15 information from the external environment, from internal environment, we're sending it up
18:19 then at the level of the the neurons talking to each other come
18:24 with a solution to the problem, ? In other words, they are
18:28 central processing unit. All right. of the individual neurons create clusters of
18:34 that are there to calculate what they're to do, right? And then
18:41 , that's when you send the signal to make you do stuff. All
18:44 . So you can send it to neurons where you're stimulating muscles to
18:48 You have motor neurons, we're sending to your glands. So if you
18:52 like, oh I don't know, , baking. What does that make
18:57 do? Fresh brownies? Oh Yeah. I mean just thinking about
19:02 brownies right now kind of make you elevating, don't they? You can
19:05 them. Your memory pulls that smell your brain. Can you can you
19:10 , can you smell the baking brownies now? Yeah. Right. It
19:15 sends information to other cells to do . So this results in consciousness.
19:23 an awareness a self awareness of what's on around you, right? It
19:28 result in a perception in terms of . If someone comes up to you
19:33 grabs you by the hand, you them and you recognize I'm being
19:38 that's both conscious awareness, but also physical uh sense of, yeah,
19:44 is touch going on, right? is something that we've come up
19:50 right? The idea of being able communicate using sound or facial expressions.
19:56 when I see this, look across face in here, it tells me
20:01 either bored or angry at me, ? And then there's this look.
20:06 yeah, I have no idea what talking about. See it's, it's
20:10 form of language reasoning, right? say you're hungry and you see in
20:17 trash can, it's kind of stacked with stuff, but on the top
20:20 a untouched unopened sandwich. Do I the untouched unopened sandwich or is that
20:28 when I'm not hungry? If I'm starving, it's gross. But if
20:34 was hungry, I might eat that . All right. There's a
20:41 memory, things that you think about that you can remember both to keep
20:46 alive and those things that actually make happy, your emotions. These are
20:50 things that are governed through the nervous . All right. Now, we're
20:58 gonna go through embryogenesis and how the system is formed. Thank goodness.
21:02 is rough. All right. There's lot of information there. But what
21:06 want to show you here just very is that neurogenesis results in cells migrating
21:12 forming the structures that we're we're gonna talking about here in the future,
21:17 early on during embryogenesis. What we're to see is a specific type of
21:22 migration. So cells basically migrate from to layer to layer. And what
21:28 going to discover a little bit later that there are six layers in the
21:32 . And so what the cells are is they're migrating upward and outward,
21:37 a radiation. All right. So you think radiate, they're moving from
21:42 to outside. Ok. So this going to be dependent upon specific
21:48 In other words, cells telling cells to do. But as you grow
21:54 , so you know, if you know puberty is kind of like what
21:59 caterpillars do. All right, you've what a caterpillar does. Caterpillar turns
22:04 a butterfly. So puberty is like turning into butterflies. All right,
22:09 a lot closer than I am. that's why I'm kind of calling on
22:13 . What we've discovered is that the brain basically completely remodels itself during
22:20 which isn't surprising you're going from a reproductive organism to a reproductive organism.
22:26 right, one that's capable of And so there's like you basically become
22:31 in hormones. We are all familiar that. And when we think of
22:34 we think of hormones, right? so there is this massive restructuring that
22:39 place, that's probably more chemical than , all right. But just think
22:45 brain will start off as mush and gets reused and then reformed. And
22:49 part of that reformation is this migration cells moving to where they need to
22:55 to form the proper neural networks in for you to function appropriately. And
23:00 now what we do is we don't outward instead, instead we migrate primarily
23:06 the layer that they're found. So is kind of tangential, right?
23:11 they're dependent now on the signals of surrounding cells. In other words,
23:15 astrocytes and all those cells that have been put in place, how do
23:18 neurons know where to go and who talk to? Well, the astrocytes
23:21 them and they stay within that range they stay within the layer in which
23:25 are actually placed here during embryogenesis. when they grow, what they do
23:34 they extend their neurons and move based chemical messages. And this is what
23:40 called chemotaxis. Chemotaxis is a generic just referring to any sort of specific
23:46 of chemical signal that causes movement. chemical taxis refers to the tactic or
23:54 is where it's coming from. the older I get, the more
23:59 realize you guys have zero experience with , you don't spend any time in
24:02 of the television because youtube and Right. But if you didn't know
24:09 a channel on cable or Hulu or thing that you could, that your
24:13 subscribe to. And it's called the Channel. And in the summer they
24:18 to freak everybody out by having a called Shark Week where it's all shark
24:23 all the time. It's awesome. all sensational and it's crazy. But
24:28 of the things they talk about in in shark wheats is usually they talk
24:32 Mako sharks, which are highly, sensitive to chemical signaling in the
24:37 So basically, you can put a of blood and that drop of blood
24:40 kind of the chemicals in that blood of diffuse and disperse. And a
24:45 can pick up that signal and follow . And it's really interesting because a
24:49 just kind of swims along and when come across that signal, then they
24:53 of slow down and they start doing long sweeps and what they're doing is
24:58 trying to hone in on where that comes from. All right. And
25:02 they get the signal gets bigger, get shorter and they'll start swimming in
25:07 finally they can peg where that signal from and find the wounded fish or
25:12 wounded surfer or whatever. OK. sim sim similar to Chemotaxis. It's
25:20 Chemotaxis because you're talking about a whole , right? But Chemotaxis here
25:27 I have a whole bunch of little pieces that are going out from my
25:34 dendrite. So it's like I'm just out little signals and out here are
25:37 series of receptors. So this whole right here is referred to as the
25:42 cone. And if I pick up chemical signal that's going to cause me
25:45 keep growing in that particular direction. so this is how the neurons not
25:51 find each other because they're telling each where they are. So you can
25:58 sort of branching so that you can larger networks or you could basically
26:02 hey, um don't grow this So you can kind of force it
26:06 grow where you need it to And it's this that allows us to
26:13 that kind of plasticity that I referred yesterday. Remember when I said plastic
26:19 we have plastic brains, but it's Barbie brains, it's plastic in the
26:24 that it develops. Now, what want you to do is you can
26:27 at this if you want to, I want you to focus here.
26:30 right. And I think this is pretty good picture. So during
26:34 your brain creates a whole bunch of which are represented by the dots.
26:39 then those cells are created and formed the network to talk to each
26:43 OK. So we can see this talks to this one, this cell
26:47 to both those two, you and you can see here this one
26:49 the middle does all three. All . Now as you go through
26:53 you create experiences, you do right? And what that happens is
26:58 that that's going to create interesting They're going to try out to create
27:03 unique types of synapses. So you see here, I'm kind of creating
27:06 growth out in this direction. I'm growth in this direction and so on
27:10 so forth. So this cell is talking just kind of like, you
27:14 , I don't know, like on first date basis, type type
27:17 right? Maybe you text each other or twice that neuron is not creating
27:22 solid network. It's not part of network, it's testing the network.
27:26 let's say you are doing something like across the street and as you're walking
27:31 the street, oh, I don't , you always get hit by a
27:33 but they honk and get out of way. And so all of a
27:35 now you have this experience, And what's gonna happen is you're gonna
27:40 this. And so it's going to that experience by the synapses that have
27:47 formed. All right. So you're making new synapses and you're always destroying
27:53 until you establish a network and that's going to be gone here. I'm
27:58 and reinforcing. So when you when you come up with, come
28:03 with information, you're not taking information storing it in a single cell
28:08 what you're doing is you're building a of interactions. All right. So
28:13 gonna try to paint this picture so it doesn't sound so weird. They
28:17 two, are they scientists have done different experiments. Two papers came out
28:21 the same month in the same journal . One was an experiment that was
28:25 in rats. One was an experiment in humans really, really cool.
28:28 the rats, what they did because can do this with a rat is
28:30 basically drill a hole through their skull you put the little electrodes in there
28:33 you can actually place it directly in brain so you can record the activity
28:37 taking place in the brain. And they did, they put a rat
28:41 a maze and it was a figure maze like this, right? So
28:44 they did is they train the rat you'd run to the middle of
28:49 of the eight and then you'd get a treadmill and then what you could
28:53 is then you jump off the treadmill then you do the other eight or
28:56 other half of the eight and then get up on the treadmill and that's
28:58 they do. So basically you're doing figure eight, but every time you
29:01 in the middle, you have to on the treadmill. All right.
29:04 they're recording the brain of the rat it's doing this. And they can
29:08 watch in real time what the synapses firing. So they can literally see
29:12 activity of the brain that's going Right. And they could predict when
29:16 , when the rat was going to a mistake because they could see in
29:20 synapses when it would fail to do it was trained to do because they
29:23 seen what it did while it was it. Right. So it would
29:27 like, oh, it knows to through the middle so they could see
29:30 . But, oh, it's gonna to actually jump on the wheel and
29:33 . It's just going to run the half of the eight. Ok.
29:37 . All right. So I can it in rats. All right.
29:41 journal, same month or, or that same, that same article uh
29:46 . Right. So they had epileptic . So they were trying to determine
29:50 , how does memory work? you can't drill holes in patients
29:53 Instead you wear the really funny So, it's the bathing caps or
29:57 swim caps where they put the 10,000 on there and kind of watch.
30:01 right. So what they did is watch had, had them watch scenes
30:06 a, like a TV show or movie or something like that. And
30:10 they recorded as they're watching to see the brain was recording that information and
30:16 they would ask them, what did see, explain the scene and they
30:21 see when the brain would repeat the prior to them telling it. So
30:27 other words, it had recorded the between all the neurons. And so
30:32 be like, OK, this is pattern, this pattern matches what they
30:36 . So they're gonna actually tell me what they saw and it's gonna match
30:40 was actually on the screen. And if the pattern was off, they
30:44 that they were gonna make a And miss uh like, oh,
30:48 don't remember or oh I, this what happened. So that was what
30:52 happening. And the reason that that occurring is because you are creating whenever
30:58 do a memory, whenever you have action or anything that is stored in
31:02 term, creates different synapses that gets creating different synapses practicing, strengthens
31:10 And then the things that you don't are destroyed in that interaction in that
31:16 . Now, if cells aren't the interaction is now the way you
31:19 look at it is let's say the of us are neurons and I'm talking
31:23 two, but I'm doing something like don't know, dribbling a basketball,
31:27 dribbling the basketball is reinforced here, not here. So what I do
31:30 I actually withdraw my, my So I'm no longer interacting over
31:35 I'm only interacting here and that's how are formed. That's how, when
31:40 do the practice over and over you're strengthening that particular thing. So
31:45 know how I told you how to , right? And saying, how
31:48 you study, you write everything So you create a pattern,
31:53 you reinforce the network and then what I say? You practice,
31:58 practice over and over again. So when you go on the test,
32:01 not like, well, I there's there you're actually revisiting and redoing that
32:06 that I told you. That's why tell you to do it the way
32:10 do it. This the, the that I've told you because it just
32:13 what your brain naturally does. Do have a favorite song? It would
32:19 so fun to just record you singing out, you know, or even
32:24 thinking it right? As you listen it, it would be really
32:30 Uh-huh. They see, they don't the actual individual neurons, they see
32:35 pattern develop in the brain. Right. So, so, so
32:42 you're gonna create an action, we're , we're gonna kind of see this
32:46 little bit as we go through the system. Remember, your activity has
32:51 rehearsed and done hundreds of thousands of before it actually gets done. So
32:59 me going. OK, I'm taking step forward, lifting my leg and
33:03 this. My brain has calculated hundreds thousands of times how to make that
33:10 forward and it's already making corrections in time as I'm going along. It
33:15 absolutely phenomenal how fast your brain And there are days where it feels
33:19 it's not moving at all, but is cruising. That makes sense.
33:24 of. Yeah. Yeah. So why you can see it happen because
33:28 that before the action takes place you're processing. Yeah. Mhm.
33:39 it's actually, it's, it's stuff the cells themselves. I mean,
33:44 , we're still trying to figure out actually is the cause of Alzheimer's.
33:48 mean, you know, for years years and years it's plaque,
33:50 plaque, plaque, plaque, and looks like plaques are not the
33:54 Plaques appear to be just one of things that appears. And so I
33:58 there was a paper, I didn't it. I just remember it coming
34:01 . I was like, oh, , we've discovered really what the problem
34:04 Alzheimer's is. And I'm like, , I don't, I don't
34:07 I'm too lazy. There's something on , I'd rather watch. So,
34:11 , um, it's not the failure the, of these because the weird
34:16 in Alzheimer's right is you'll see people Alzheimer's, um, and any sort
34:22 , uh, uh neurodegenerative disorders like is you'll see them have bursts of
34:27 , right? Where it's like, , here's this. So there's something
34:30 impeding that actual, uh, activity actually occurring. So I couldn't tell
34:38 what it is. I mean, , I not my area. All
34:45 . So the way that information is , the way you can think about
34:50 does my nervous system work? It's to be coordinated and integrated into,
34:57 these uh pools or into what we call a circuit? All right.
35:02 it's not a, here's a here's a cell, here's a
35:05 it's usually hundreds of cells talking to other doing the calculation, whatever the
35:12 happens to be, right. So can be uh these pools can be
35:19 . And so when we say we're saying, OK, in this
35:23 region, we have a series of that are clustered together that are working
35:28 to deal with this particular question or or, or um activity or whatever
35:33 happens to be. All right. other thing we'll see is very often
35:38 neurons aren't just localized, they can distributed throughout. And so if you've
35:42 seen uh uh like a cat you'll see like, oh this is
35:46 region for small you do over this is the region for speech.
35:49 then you look at the a a itself and it's not just that it's
35:53 there are parts of the brain all that are involved, but it happens
35:56 be there's a primary region for speech then there are other areas that
36:01 And so this distribution is not an uh a strange thing. Yes,
36:06 . I heard this. It Right. That doesn't surprise me at
36:26 . I mean, it does in sense that speech is, comes from
36:30 specific area of the brain called, don't know where singing would come
36:33 But the fact that the words and that other information is stored in other
36:38 , it's being, being able to . So we have an area of
36:42 and we have an area of understanding , two different areas, right?
36:47 so it wouldn't surprise me that that . There are things that your brain
36:50 do. Oh You want weird. weird. You can actually cut your
36:55 in half, right? And your side of the brain won't know what
36:58 right side of your brain is doing . And so you could literally have
37:03 two sides interfere with each other where fighting each other. So like your
37:08 and stuff like that. Yeah. When I saw it. Mhm And
37:23 said, oh why? Oh I That's right. So what we're going
37:32 see here a little bit later, today, but that the brain has
37:36 . You'll hear the term people say left brain, I'm right brain.
37:39 , that's a bastardization of lateralization. right. What that means is that
37:44 of the time your brain communicates cross . So the left and the right
37:49 communicates so that it can do whatever but it's capable that some or some
37:55 of the brain are divided in In other words, the left side
37:58 the brain, for example, has heavy speech component. In other
38:02 the ability to speak and the ability understand speech are only found on the
38:06 side of the brain. Some of might be the right side of the
38:09 if you have the reverse imaging. , but the idea is that you
38:13 have the same areas on both So it's like if you damage that
38:18 out of luck, you can't speak . But as you were saying,
38:23 know, the idea of like my hand picks up and I don't know
38:28 I actually did it. It's because the left side of understanding what you're
38:32 and stuff is over here. So some pretty, pretty interesting wonky things
38:38 go on. All right. But , so we have this distribution is
38:42 I was trying to get them. right. Another thing uh there's going
38:45 be a restriction to the number of and outputs which should make sense.
38:48 don't want every part of your brain receive all the information and to send
38:51 all the information. So it's basically part of the brain is going to
38:55 specific to what its job is. right. So there's, there's very
39:00 the part of the brain that's responsible uh for understanding sense, the sense
39:05 smell is not going to be the of the brain that also plays a
39:09 in the sense of taste or the of touch or vision, right?
39:13 you're basically uh limiting what sort of goes in and where that input goes
39:18 to. All right, we'll see when we talk about the different regions
39:23 the cerebrum, and then this should also pretty overt or obvious is like
39:29 can be simple or complex. We to focus on the simple just to
39:33 us understand. All right. So gonna look at four basic types of
39:37 here that are simple circuits, but can be used to create much,
39:42 more complex things. All right, rule to follow the more neurons you
39:48 the more, more interactions you have more complex it's going to be.
39:52 so that's going to result in synaptic . And so it's just going to
39:57 down the processing. So the more you become, the longer it takes
40:00 process some sort of ability or action whatever it is, right? So
40:08 we go, we're gonna look at and complex circuits. So that's kind
40:11 the transition understanding that we're going to these to create these much, much
40:16 vast uh much more difficult uh neural . But a simple cir circuit is
40:22 , really basic, these are not common. All right, we're gonna
40:27 much more of these complex circuits, right. So basically this is a
40:32 circuit, one cell talks to another at the end, pretty straightforward,
40:36 . OK. That's simple complex is there are going to be multiple
40:41 Now again, in this little model they're showing you, there are two
40:45 , we got cell A talking to B, but cell B also feedbacks
40:49 talk to cell A which then can cell B. And so now you
40:53 something a little bit more complex. have a positive feedback loop here in
40:58 particular model. So you can see with complexity, you're gonna have these
41:04 connections. All right. So let's a look at some of these different
41:09 of circuits. There are four types you should know. All right,
41:13 first two types are converging and All right. So convergence means I
41:19 to a point, diverging means I away from a point. All
41:22 And you can see here here is divergence circuit. I have a single
41:25 and I'm sending that signal to multiple places. So I'm going away from
41:32 point, I'm getting broader and broader broader as I go along. So
41:35 an amplification that's taking place here. right. So where do we see
41:43 lots of movements type of stuff? to think what else we hear?
41:46 yeah. So like the example I is neurons that simulate walking. They
41:51 stimulate balance, right? Because what walking not falling? Right? So
41:57 time I lift up my foot, have the ability to fall over.
42:02 what I'm also doing is I'm not just the muscle to lift up
42:06 leg, I'm also telling the muscles the other leg to go down and
42:09 maintain the balance. So I don't over to the left or to the
42:12 . Instead, I'm putting my weight so that I can come and then
42:17 myself on that. That would be example of divergence because I'm going to
42:21 these different muscles to create uh to that single movement. So there's hundreds
42:29 hundreds of things that are happening So that's divergence. So, pre
42:35 input, postsynaptic input is much more in a converging circuit. This is
42:40 we're going to concentrate. So you see here, information is coming to
42:42 one thing. So these are very common we're basically focusing in.
42:49 So uh the example I have I'm using salivation as an example.
42:57 right. So salivation is a single input. What is salivation? Where
43:02 I where, how do I start ? What makes me salivate?
43:06 it's not just the things that are my taste buds, right? It's
43:10 what I see. It's also what smell, in fact, smell and
43:16 go hand in hand, right? you are sick, everyone knows when
43:20 sick, nothing tastes good, Because the olfaction is a huge,
43:23 role also tactile, right? If in your mouth and it tastes,
43:28 know, if it feels good that to the dimension of the taste.
43:33 all of these different special senses give to a simple function for me to
43:40 understand the food that's in my All right. That kind of makes
43:45 . So here I'm getting input from areas and it's converging on the one
43:53 . All right, rhythm generating circuits we have three different neurons in our
44:00 model. You can see neuron A sending a signal to neuron B and
44:05 C, right. So neuron here's neuron B, there's neuron
44:11 So this is the ax on that . So these two things are,
44:16 getting signals, this one signals to one. This one also signals to
44:21 . But what am I also I'm getting a positive feedback so that
44:24 can reinforce this thing over and over . So what's gonna happen is you're
44:28 to create a rhythm. All breathing is an example of a,
44:32 a rhythm. All right. What is, is a single neuron fires
44:37 the circuit. And so what ends happening is you get bigger and bigger
44:40 bigger and bigger and bigger signals. so what you're doing is you're recruiting
44:44 muscles, creating greater tension which causes to go and then you get a
44:51 from the outside that says stop and all those muscles relax and then you
44:58 it all over again. So that's pattern that's being generated. It's just
45:02 rhythmic pattern of tidal waves of breathing and exhaling, breathing in and exhaling
45:09 and over again. Typically, with type of circuit, you're going to
45:13 what are called CPGS. So these central pattern generating circuits. Um Walking
45:19 another one. If you go outside watch people walk for a while,
45:23 start noticing that they have this pattern they do, right? Everyone kind
45:26 has this arms moving opposites, go and watch him simple pattern. And
45:41 you have listen to music, you'll noticing that they move to the rhythm
45:44 you're listening to. Not that they're to just what you're listening to.
45:49 right, sleep wake cycle, these of up and down, up and
45:54 , these are all going to be these types of circuits that are
45:58 All right. Now, this is a model. So don't say it
46:01 to have ABC. It's the The last one is a parallel after
46:06 here. What we're doing is we're create this massive uh uh final
46:10 All right. And so in this , how many do we have,
46:12 have an ABC de and F and they're all converging on F over
46:18 right. So A is stimulating So it gets its signal but also
46:25 to uh B which signals to E this is gonna be a delayed signal
46:30 to f this one is shorter than one. So this one is going
46:35 fire and hit this one before this does. So you can think like
46:38 a hits this first, then C D then E so this cell is
46:47 boom, boom, boom, boom. So you're basically getting a
46:51 signal being charged out of that last because of the series of uh stimulations
46:58 it's receiving. All right, it's types of circuits that we believe are
47:07 in higher order thinking like, should grab that sandwich off the top of
47:13 trash can that hasn't been touched? . Can I cross the street?
47:20 I enter into traffic? You like when you're driving your car?
47:27 . Is that person interested in Do these words mean what I think
47:32 means when I'm reading a book, sort of stuff? High order
47:41 So as I mentioned, we're gonna a lot of these very early on
47:46 life. All right. And then going to either maintain these circuits or
47:51 going to uh demonstrate and restructure Have you ever watched Children?
47:58 like, like a baby, like things and just shove things into their
48:03 ? Have you noticed that? That's they do. Have you ever wondered
48:06 are they just stupid? Probably. I mean, but do you think
48:12 a behavior because they don't know better what do you think they're really
48:21 they're exploring their world through their sense taste. Right. They're not just
48:28 on stuff. I mean, some they chew on because they're teething.
48:31 . But it's like, you they grab keys and you're like,
48:36 , they grab the cat poop and you're like, chasing after them,
48:39 they're trying to figure out what's food what isn't food. Right? You're
48:44 the world, right? And that's early on. Have you ever seen
48:51 , like, grab their foot? ? And then like, put it
48:55 their mouth and they're like, you , and you're like, man,
48:58 really cool. I wish I could , do that. No,
49:01 but you notice that right? they're discovering or like when they reach
49:06 , they're trying to teach their muscles their brain how to be coordinated
49:12 right? When a baby starts what do they do? They learn
49:16 pull themselves up and then they fall , they sit down and then they
49:20 themselves up and you look at they would do these repeated actions over
49:24 over and over again. What are doing? They're developing those circuits,
49:31 ? And when we learn stuff, doing the exact same thing. All
49:34 , we just may do it in way that doesn't seem particularly efficient.
49:37 know, I come sit, let's come sit in a room in straight
49:41 and listen to some old guy yammer about this stuff for hours.
49:47 Have you ever sat down with a video to learn how to do something
49:51 , I don't know, two in car. Something that you would never
49:54 able to do otherwise. Yeah, the same thing. You're just retraining
49:59 brain, reorganizing the circuits. All . Practice makes perfect. The more
50:06 do something, the more likely you're do it. Pick on the athlete
50:17 a little bit. Right. What you guys do during practice? Do
50:22 , do you, like, do , like very early? I
50:24 I know you guys are now beyond this. But like, do you
50:27 up on the block, get yourself position, jump in, come back
50:32 , get up on the block, in, do it over and over
50:35 over again. Right. Because what you doing? You're, you're training
50:43 neural network so that when you hear gun, the eat, you
50:48 when to go that you don't prematurely off the block. Yeah.
51:08 Yeah. Absolutely. Yeah. It , it's when you stop practicing.
51:22 . Yeah. I still play video . I'm better than my kid in
51:27 games and he's better than others. could not play Fortnite to save my
51:31 because that building stuff. Oh, , I'd be sitting there going.
51:34 button do I push to, to, to not be dead?
51:37 it's like, ok, it's time start shooting people. I've been playing
51:40 person shooters since I was y'all's Right? I'm as fast as
51:46 My, my reaction time, if saw me drive, you'd wonder why
51:50 not racing because my reaction time is quick. I do it all the
51:55 . I play video games. My is terrible with reaction because she doesn't
51:59 her brain to do stuff like She has, it takes more time
52:02 process stuff. Now I have that recording and so she can come and
52:07 me, I tell you, but , that's in essence what you
52:10 the more you practice to do the better you become at it the
52:14 you're training these networks, right? so it was like what I was
52:19 yesterday when we were talking about the kids, you know, the wax
52:22 , wax off. Why did it or pick up the jacket, put
52:25 the jacket, put the jacket, it on the ground. Why does
52:28 work? You're training the muscles to , right? You go to a
52:33 , you know. And, like, so I played football,
52:36 , I pretend like I played I was terrible. They put me
52:40 a foul because, you know, I play football, right? And
52:44 do you do? You do the ? Why do you do the drill
52:47 and over and over again? So it comes time to the game,
52:50 not sitting there thinking, ok, do I do in this situation?
52:52 just respond because it doesn't need to the conscious thought. It needs to
52:56 the neural response. Yeah. So wearing this plastic throughout life? I
53:07 , and so, I mean, your phones you have, like,
53:10 watching something, you get that like Ebony, the Ebony or there's the
53:15 one, the stupid game that you know, play this game to
53:18 your IQ. Ya, ya, . I mean, that's a
53:21 It doesn't improve IQ, it doesn't intelligence quotient. But we know that
53:26 you, if you practice puzzles and things, you, you try your
53:31 . In other words, you, work it out, it's going to
53:34 , you know, functional in the that you're able to do more
53:41 It's when you stop doing stuff that become worse at it now. All
53:46 . My 96 year old grandmother said , I don't want to drive
53:50 Ok. Good. Good for all us. Right. You know,
53:54 her reaction time less? Yeah. know, probably. But, you
53:57 , it's because she doesn't drive all long through rush hour traffic. Could
54:01 have done it? Yeah. you know, she didn't want to
54:04 that, you know, and that's most of us do over time.
54:08 stop doing things, you know, , I don't know how many years
54:13 stopped exercising. It was wonderful because sucks. Sorry. You know,
54:19 it's like, ok, I think should exercise and so now I have
54:22 mass. I live more than I did when I was in high
54:25 You know, I'm stronger, muscle , you know. But, you
54:34 , it's just a matter of I go every single day and
54:37 I change, you know, I doing the same thing over and over
54:41 and then I add in and so then once I add in,
54:44 keep doing it and I just keep up. So practice, that's all
54:49 is. Practice. All right, have a proper wiring, you can
54:54 the function. All right. How you get the function? Well,
54:58 do you get the proper wiring? keep doing it over and over and
55:01 again. So your coach is doing right thing making you do the crazy
55:05 over and over again, right? we're doing in this very often is
55:14 creating reflexes. There are cranial reflexes spinal nerve reflexes and reflexes have this
55:20 dimension to it. But what we're do is we're gonna keep it simple
55:23 . All right. So a reflex definition, all right, is a
55:29 preprogrammed, right? So, in words, it's already there inherent in
55:33 involuntary reaction of a muscle or a to some sort of stimulus.
55:38 this is one that you're probably very with, right? Have you ever
55:42 the knee one, the knee knee jerk reflex is real simple.
55:47 mean, we could, I could up here and do it to
55:49 I mean, all I gotta do sit up there cross my leg and
55:51 just hit the right spot. And I'm doing is I'm hitting a tendon
55:54 feels the stretch in the tendon which me to kick the leg. All
55:59 . That's a program response. What's stimulus? In this case, there's
56:01 sort of sensory input, that's the that I'm feeling. So I'm putting
56:06 into that tendon. So the response , is, is basically to cause
56:12 kick. And so how does that happen? Well, there are a
56:15 of neurons involved but it didn't need go up to the brain. I
56:17 need to process that information. And know, I've been hit that
56:20 So I think I need to it's actually occurring at the level of
56:23 spinal cord. I don't even have think about it. It doesn't even
56:27 up to my cranium. I'm not consciously aware that I'm doing it
56:32 in, in most cases pre programmed that this response is going to be
56:38 result no matter how often I do , I can't stop it. All
56:43 . As in voluntary mean, I suppress it, right? No conscious
56:49 . All right. So like I , this is gonna be done at
56:51 level of the spinal cord, you have stuff that goes up to and
56:55 to the cranial region. But most reflexes are going to be here
57:00 the spinal cord. So there's basic . These are the unlearned one.
57:03 is what we're looking at here in particular picture here. All right,
57:07 is the suckling response. You get little baby, you know, up
57:10 a certain age and if you sit and rub their face like this,
57:13 turn their head and they'll try to that finger because they know that built
57:20 into their bodies is when something is my face right around here. That's
57:25 I need to latch onto and begin . That should be a nipple.
57:34 . Mhm. I have one. . Um, no, I wouldn't
57:49 stupider. But, but, I mean, I know what you're
57:51 to say. Right? Is does it have a long term neural
57:55 ? Yeah. My, my cousin a heavy, heavy, heavy drug
57:59 . I mean, um, and my age and he's in a nursing
58:02 and he's in a wheelchair right He's had other issues as a result
58:08 that. You know, heart uh, stroke other things because you
58:14 your body. It's gonna catch up you eventually, right? Um,
58:19 sweetest guy ever. But I he's just, I mean, you
58:21 at him, he's like a 70 old man in terms of physical,
58:24 physical shape. Right. Um, , yeah, it's so, it
58:29 damage these networks whenever you smoke Uh, remember what you're doing is
58:33 doing the same thing to meat. made of meat, right?
58:36 if you smoke meat, you get , you smoke yourself. What are
58:39 doing? Your barbecue in your barbecue and your other tissues.
58:45 stay off the drugs kitties there. , with regard to a,
58:50 other type of reflexes. So, reflexes, like I said, these
58:53 built in, uh, these are unlearned. You just do and
58:58 there's the ones that are what are the condition reflexes. All right.
59:01 these are required acquired after practice and . So, like, for
59:05 when you see a yellow light, do you do? I was waiting
59:11 the speed through. That's, that's we've been conditioned. I don't wanna
59:15 at the red light. I'm I'm gonna accelerate into that intersection.
59:20 ? That's, that's an, that's stupid example, but it's one that
59:22 like to use. But I any sort of, of things you've
59:25 conditioned from years and years of going school that when you hear the
59:29 that's when you pack up your stuff get up and go. Right.
59:31 , you know, I have 10 to get to my next thing.
59:36 . That's a conditioning right. you've learned about conditioning through Pavlov.
59:40 had a dog, right? You Pavlov and his dog So, what
59:44 Pavlov do? He rang? The . Fed, the dog rang,
59:47 bell fed, the dog rang, bell fed, the dog rang,
59:50 bell didn't feed the dog. What dog do? Yeah, that's what
59:54 story goes. I'm sure the dog him. Right. But,
59:58 so the dog knew when I hear , that means food comes.
60:03 You have something in your pocket when buzzes. What do you do?
60:12 gotta look at it. I gotta out you've been trained just like Pavlov's
60:19 . There's something that my phone needs tell me and everybody who programs those
60:23 apps on the phones knows this. so they program to have you pick
60:28 the phone every couple of minutes you've conditioned. Alright. Now there is
60:37 conditioning and bad conditioning. All that's an example of bad conditioning.
60:43 to ignore your phones, I think the 1st 18 years of my
60:47 if the phone rang, I didn't it up, you can leave a
60:50 . If you're really important, I'll you back. That was a function
60:55 my parents who hated to talk on phone as well. So right,
61:00 right here is the single most important that you can take out of the
61:04 six weeks. All right, it to about four different things that we're
61:08 . So if you learn this and not hard, that's the good
61:11 This is an easy, easy If you learn this, you've learned
61:16 the nervous system. It's kind of . All right, because you'll see
61:19 like again, it's like, oh , I recognize this. OK.
61:23 what we're gonna do is we're gonna look at it in terms of the
61:25 arc, which is what we're showing . Reflex arc is very, very
61:32 . There's five parts to it and gonna show you we're gonna start where
61:36 have a receptor. So you can in this uh picture right up
61:40 here's a receptor. We have an nail, right? And then electric
61:45 because it has lighting. Sure you pick it up. Are you
61:52 OK. All right. So you imagine if the nail goes into my
61:57 , am I gonna feel it? it going to be painful right
62:02 Notice the painful stuff is, is perception thing. What it's gonna do
62:05 it's going to stimulate the activation of pathway. All right. So the
62:13 is part one, it receives the , it activates a pathway. The
62:18 is called the A pathway. A I'm, I'm, I'm, I'm
62:22 saying a all right, because in afferent and efferent sound an awful lot
62:28 . So A&E is what I'm going say so that we can distinguish
62:32 All right. So we have an pathway, a pathway goes in and
62:37 it's going to go into is it's to go into the central nervous
62:40 So what we can see here is can see now the division between the
62:44 and the central. This is one the reasons why this is an important
62:48 . All right. So the pathway is called the a pathway, we
62:53 into the central nervous system and we see that we're going to come across
62:58 neuron in the central nervous system. right. In this particular case,
63:01 looking at an interneuron, you won't have an inter inter neuron. You
63:04 have multiple inter neurons. All So the thing here is that we
63:08 something onto which we are sending that . And that thing that we're sending
63:13 signal in the central nervous system is to as the integration center. It
63:17 the cell or cells that are responsible processing that signal. What am I
63:23 to do with this? All So it has the program. If
63:27 receive the signal, then this is you're going to do. So that's
63:31 going on here. It says, we got stabbed by the electric
63:36 I I understand when I get stabbed the electric nail, we have a
63:39 that needs to take place. So do we do? We're gonna do
63:42 . So let's send out that signal it comes out the EENT pathway.
63:47 the third part. Sorry. Fourth got to make sure I'm counting
63:52 So A is in E is out that E goes and innervates the
64:00 What is an effector? It causes effect in this particular case because I'm
64:05 stabbed by the electric nail. I'm my arm away from the electric
64:10 So in this case, the effector to be a muscle. All
64:15 But it doesn't necessarily need to be muscle, let's say up there,
64:19 receptor is an olfactory receptor and I fresh baked brownies. What is the
64:25 going to be? It could be muscle. But what what do I
64:30 it to be gland? Salvation, . So you see this is a
64:37 that's repeated over and over and over the nervous system receptor Afare pathway integration
64:46 , efa pathway effector oop. That terrible, right? So if you
64:53 these five things and start remembering, , if this is the pattern I
64:58 now then apply it to say for , a basic reflex, I'm in
65:02 shape, right? I step on . I don't break my mother's
65:07 I lift my foot up. I'm touching something hot. What do
65:11 do? Pull my hand away? . Notice I'm not even perceiving what's
65:19 on here when you touch a. . So if you click that link
111:13 the recorded lectures on the front page on canvas, you can actually do
111:16 search, just use either my name the course name and literally all the
111:24 from when I started teaching. Are ? Except for, like, if
111:27 didn't save, if something bad happened the recording. But it's basically me
111:34 the same dad joke on a different . Yeah. Yes. Yep.
5999:59
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