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00:00 | Okay, this is lecture 14 of and we will start discussing the central |
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00:08 | system some basic concepts and the development the central nervous system. Some structures |
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00:15 | functions of the major parts of the . N. S. As |
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00:19 | So if you look at this diagram this uh section will have a lot |
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00:27 | diagrams and typically on exam two I quite a few questions on labeling that |
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00:32 | related to the brain parts and And you should note the parts and |
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00:39 | functions because the questions may ask you the function to point to certain part |
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00:43 | the opposite may pointed to certain part see what is the function of this |
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00:48 | part of the brain or or nucleus such. So on the left, |
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00:53 | you have is you have different animal from rat to dolphin aligned in |
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01:02 | So this is to scale on the and you can see that rat brain |
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01:08 | barely just a centimeter and some, dolphin brains are actually larger. And |
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01:18 | we look at this and we should fern ologists, the dolphins are smarter |
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01:25 | humans because they measured it partly by size of the organ. So uh |
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01:32 | would be smarter than humans too. some basic features that repeat in these |
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01:39 | brains here, it's no longer to . But here it's to show you |
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01:44 | larger images how they differ that if look at the human brain it has |
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01:52 | complex imaginations and Rijs. They're called and Joy ride. You see that |
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02:02 | structure in other animals and dolphins. then you look at more primitive animals |
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02:09 | you see that they don't have this and gyros structure, rodents or it's |
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02:17 | limited what these salsa do. They change the positioning. The architectural positioning |
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02:26 | neural networks, increases the surface area increases the complexity of the brain |
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02:35 | And so english language, there's sometimes saying a lizard brain or smooth brain |
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02:42 | the lizard brain. A smooth brain to a smooth brain that has no |
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02:48 | and dry, right and really kind a simplistic attitude. Uh Forward life |
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02:54 | problem solving as it is being used , uh you can see that certain |
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03:01 | will have certain structures that are much relatively to the rest of the size |
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03:06 | the brain, rats and rabbits. can see they have these huge olfactory |
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03:12 | in the front and that's a factory . So a sense of smell and |
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03:18 | lot of the brain area. A of its mass is dedicated to |
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03:24 | You can see that when you look the humans, you will see these |
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03:29 | olfactory bulbs, you can barely identify here in this diagram. Here's olfactory |
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03:34 | in dolphin there even larger here but still very small compared to the rest |
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03:38 | the size of the brain and then parts of the brain are developed differently |
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03:44 | animals. So the dolphins will have very large served malum referred to also |
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03:50 | a little brain. Humans will have sizable cerebellum too. Um But here |
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03:56 | can see cerebellum is almost like half the massive and C. N. |
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04:01 | . So there's certain functions that these are performing. There are certain sensory |
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04:08 | such as hearing that is improved in animals are superior even to humans. |
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04:16 | of smell in certain animals, superior humans. But we still find ourselves |
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04:24 | the top of the food chain, to mars and playing politics and really |
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04:36 | , ruling the rest of the animal uh collectively on your own, if |
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04:43 | in the forest, you're pretty helpless the rest of animal kingdom and your |
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04:48 | may not save you. But these that you see in the brains are |
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04:55 | changing throughout evolution. So how the looks like, how the circuits are |
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05:02 | the brain, what parts of the are accentuated certain animals. It has |
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05:06 | do with evolution has to do with environmental changes. It has to do |
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05:10 | the ability to procreate and survive. we talk about anatomy and brain anatomy |
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05:19 | structures. We always have to refer to some of the basic concepts some |
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05:23 | those concepts, medical concepts you may learned, such as on the orientation |
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05:30 | planes through the brain, the cutting through the brain. So the front |
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05:37 | inferior for rasta rel the back is end that the back because this is |
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05:44 | back, the back is dorsal, chest area is ventral access here and |
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05:54 | tail is posterior coddle media was in middle and lateral is away from the |
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06:04 | . And there's a lot of brain that are named after their location, |
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06:09 | lateral nucleus or so and such. you're gonna look somewhere in the middle |
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06:14 | a little bit off the middle laterally identify certain nucleus. Then you have |
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06:21 | planes through which you can cut the to visualize the inside of the brain |
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06:27 | all of the structures the cut that it in between you can say between |
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06:33 | and advances from media or midline to lateral aspects you referred to as miss |
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06:41 | cuts that really roster to carl. if you cut the brain in this |
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06:49 | , this is horizontal orientation and this orientation as we purchase kurono orientation, |
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06:57 | cuts and how this came about is we were interested to know how different |
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07:05 | in the brain looked like traditionally. you learned there was nestle stain and |
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07:10 | will stain. Will stay in all the neurons and glia and show you |
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07:13 | cider architecture. So you want to that side of architecture in three dimensions |
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07:18 | this plane and this plane that And then you can reconstruct three dimensions |
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07:24 | these different structures. Uh your anatomist these as their maps. So somebody |
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07:31 | to tell me you're looking at the sagittal section of a mouse brain and |
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07:37 | give me coordinates let's say half a apart from midline I place in my |
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07:44 | approximately what part of the brain or structure of the brain we're looking we're |
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07:48 | about are looking at just by getting coordinates and placing them in my mind |
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07:53 | where they are. So we use as maps. Now. You take |
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07:57 | map of campus and you say this the building here, this is the |
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08:01 | here, this is the student this is the dorms here. So |
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08:05 | use it as a map. Also these different cuts will give you a |
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08:09 | representation of this map essentially giving you dimensional representations. So cerebral hemisphere. |
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08:17 | cerebral we have lateralization of brain Right brain, the right hemisphere and |
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08:24 | cerebral hemisphere. They're responsible for slightly functions. Advanced processing, different |
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08:30 | cognitive functions and even sensory remember, this area was on this side. |
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08:36 | . And we we we saw that clearly it wasn't shown on the right |
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08:41 | of the brain. So there's other of cognitive and processing capabilities that are |
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08:47 | . Ized and to the hemisphere. stem is sort of the core of |
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08:53 | brain that's holding the brain and evolutionarily was the original first structure that was |
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09:00 | in the C. N. And these other structures cerebellum. Sub |
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09:04 | structures such as the thalamus and Finally culminating with neocortex as the most |
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09:13 | advanced and most sophisticated neural circuits in brain. So cerebellum, cerebrum and |
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09:24 | hemispheres. The process information contra laterally they send the motor signals contra |
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09:33 | So a lot of sensor information will this hand, right hand will cross |
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09:39 | the left side of the brain and I'm moving my right hand, that |
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09:44 | my left motor cortex is telling my hand to move my right motor cortex |
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09:49 | telling my left hand to move cerebellum the other hand will process. One |
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09:55 | the functions of cerebellum is movement control it will adjust that on the same |
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10:02 | which is referred to as iptc lateral . So left cerebellum will control movement |
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10:07 | on the left, right on the side. Brain stem is where you |
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10:13 | a lot of the cerebral to sarah between cerebrum and cerebellum, the cerebral |
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10:21 | and cerebellum and between cerebellum and So a lot of the connections these |
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10:28 | areas are very much interconnected. A of these connections are gonna be running |
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10:32 | brain step brainstem will also contain nuclei are responsible for the vital body functions |
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10:42 | what you've learned in the neuro transmission is that brainstem will also contain these |
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10:48 | that specifically express subtypes of a means we looked at such as norepinephrine dopamine |
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10:57 | scattered through brainstem as we saw in diagrams from last lecture, but brainstem |
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11:05 | contain nuclear that responsible for vital body , breathing consciousness control of body temperature |
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11:15 | uh supposedly maybe this is all you to survive. Originally before you become |
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11:21 | very complex cognitively animal and it gets you know democratic or Republican party left |
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11:29 | right right. So uh this was core of the brain that existed |
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11:36 | More complex structures evolved with time and peripheral nervous system. We don't spend |
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11:46 | time. But you have a somatic is voluntary motor and sensory skin joints |
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11:53 | muscles. But you also have a peripheral nervous system which is a lot |
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12:00 | times referred to as autonomic nervous And this is really the nervous system |
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12:05 | innovates your guts not your motor and . The motor and sensory we discussed |
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12:12 | the reflex arch from the spinal But the visceral autonomic nervous system is |
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12:19 | of nerve endings throughout organs, internal , blood vessels, glands and very |
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12:28 | so very sophisticated. Mesen terek autonomic system which is basically the gut or |
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12:35 | digestive nervous system. And what's emerging this nervous system and the gut is |
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12:42 | potentially it is as complex with as players and synapses in ways of communicating |
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12:49 | the periphery as it is in the and the C. M. |
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12:54 | And this is a really interesting emergent of study how the god affects the |
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13:01 | . How the nervous system of the is related to the C. |
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13:06 | S. How the microbiome of the where you carry a lot of bacteria |
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13:14 | probiotics in your gut that are very that they not only help your digestive |
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13:21 | but sometimes they produce their own Metabolites could even cause neurodegenerative neurological complications |
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13:29 | your gut. This is a very field emerging of microbiome the nervous system |
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13:36 | connected to the microbiome and how this system is enteric is communicating to the |
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13:43 | . N. S. And what they have on each other. The |
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13:49 | is protected by the men injuries. have three men injuries. So after |
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13:55 | remove the skull you are encountering the surface. Meninges is due Ramada which |
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14:04 | hard mother. And subdural space here the dura mater is spilled with arachnoid |
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14:15 | . They're also meninges and membranes that spider like productions. And the closest |
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14:23 | right on top of the brain Most internal is the PM. Modern |
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14:29 | the or the gentle mother. So men in jeez they are protective. |
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14:36 | physically protective. Uh Dura mater is tough. It's like a skin. |
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14:45 | you you have to you cannot penetrate dura mater. Just with the finger |
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14:50 | have to use a scalpel in order cut through dura mater uh in this |
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14:57 | you have fluids so it's kind of fluid. It's gel like environment. |
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15:04 | then you have a cushion here. if the brain squeezes you have physical |
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15:08 | . You have the arachnoid that can squeezed and change its shape a little |
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15:13 | . And then you have the M. On it. They not |
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15:16 | protect but they also nourish the brain can be a source of nutrients, |
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15:23 | the PM. Otto. When we in the first lecture, the brain |
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15:29 | nations. And we said that these prehistoric cultures that were performing brain |
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15:37 | they were potentially the first neurosurgeons. as you can see underneath the dura |
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15:43 | , you have larger blood vessels that the smaller micro vessels that penetrate throughout |
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15:52 | the brain tissue. And there are where these vessels can rupture. It's |
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16:01 | stroke or it can be an aneurysm normal formation in the blood vessel and |
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16:08 | the blood vessel. And what would then is that you would have what |
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16:13 | called a subdural hematoma. So if blood vessel ruptures and they have coagulants |
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16:21 | the blood and the coagulants at the of the coagulants is to stop the |
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16:27 | , is to thicken the blood and of that blood and stopping the bleed |
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16:33 | create a thickened kind of a blood that is referred to as a |
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16:39 | And you can have him a thomas on your arms and your legs where |
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16:44 | have the bleed and you can see bruises for example. So this would |
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16:48 | on the inside soda really. And only way that you could clear that |
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16:57 | would be by opening the skull making incision in dura mater and clearing physically |
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17:04 | that wound. Just like you would this in fact and patch up the |
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17:09 | on a hand or a leg or part of the body. So if |
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17:15 | don't clear hematoma, what can happen the pressure may build up and they |
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17:22 | causing pain and it may start causing problems down down the road, like |
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17:29 | and potentially neuro degeneration in the area the area of the injury. So |
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17:34 | want to clean up that area and why you had potential interpretations. That's |
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17:40 | interpretations potentially were repeated. Because some these problems where either chronic or recurrent |
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17:47 | that needed attention multiple times through this . Yeah. Do they do they |
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17:57 | ? That's a they don't degenerate the way that neurons would degenerate. There's |
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18:04 | sis in the crisis that happens in but there's definitely aware down of the |
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18:09 | injuries. But I'm not very familiar how they degenerate. It's more of |
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18:14 | structural breakdown and in the actual Oh do they grow back? |
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18:24 | Actually you can suture some of the modern dura mater especially you can suture |
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18:30 | some of the PM. Modern and would would be belt. Yeah. |
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18:34 | was thinking more when you ask that whether they degenerate with age kind of |
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18:39 | know, become very thin and go . So good question. So ventricular |
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18:46 | , we have the supply of cerebrospinal CSF cerebral spinal fluid that bathes cerebral |
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18:54 | the spine it's produced in this area lateral ventricles that has core oid plexus |
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19:02 | produces the cerebrospinal fluid. Cerebrospinal fluid circulating through this ventricular system that is |
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19:10 | the whole brain and inside the spinal . And this is how it provides |
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19:15 | cerebral spinal fluid that bathes the neurons there's constant production of cerebrospinal fluid and |
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19:23 | of that almost on a on a basis where we basically produce new fluids |
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19:31 | and they eventually go into Iraq subarachnoid spaces and get drained. Now, |
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19:40 | there is abnormal formation of fluids, could have a developmental condition which is |
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19:48 | to as hydrocephalus. Okay, what I have here? And brain trapper |
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19:54 | again. So what is hydrocephalus? is a condition where there's too much |
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20:02 | the production of the surplus spinal fluid the draining of the cerebrospinal fluid is |
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20:07 | . If it happens during early developmental it will actually stretch the ventricles will |
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20:15 | them very large. The ventricles will pushing on the brain tissue, will |
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20:21 | the brain tissue and the brain tissue start pushing on the skull and the |
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20:26 | is soft during early development. If recall and mentioned that when newborns are |
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20:32 | , the skull plates are not even and the size of the head is |
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20:36 | big and then by the time you're it's about this big, whatever, |
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20:44 | ? So if that happens and those are not drained properly, there's a |
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20:51 | up of those fluids, they will the head and in the hydrocephalus. |
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20:58 | developmentally patients may end up with this shown here. I don't need to |
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21:05 | with this exaggerated alien, like whatever think of alien heads are egg shaped |
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21:13 | heads that are abnormally large and And how do you treat hydrocephalus? |
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21:21 | insert a tube into the lateral electrical drain the fluids. If it's a |
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21:26 | problem, sometimes you can actually leave tube in the petunia cavity so that |
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21:33 | draining the fluid and you have extra as the child is growing, it's |
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21:39 | to the child's size. Uh, is a rare developmental condition, but |
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21:49 | can also be brought out by So there's this thing that I've learned |
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21:56 | about uh 13 years ago that a baby and shaken baby syndrome can result |
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22:07 | hydrocephalus, shaken baby, shaken baby is usually when parents are very stressed |
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22:15 | and they have newborns and the newborn crying and if the parent is not |
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22:21 | altogether or they're not educated or they're not good people, they start shaking |
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22:28 | babies shut up to sleep off and shaking actually can lead the hydrocephalus is |
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22:36 | condition because it imbalances this mechanical movement the brain, the fluids, the |
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22:43 | of the fluids and can result in condition. Uh Likewise, brain trapper |
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22:51 | , potentially were used to drain those also. So there are some skulls |
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22:58 | are in in in in Children. nations that are found that would suggest |
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23:02 | potentially that was one of the conditions treated in addition to internal bleeding. |
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23:08 | hematomas. I it could be the . Yeah and the lymphatic system it |
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23:32 | could be too much for plucks is producing too much fluid instead of the |
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23:38 | 500 ml for a certain amount of is producing 2000 and the drainage system |
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23:43 | working but it's not adjusted to this of the fluid being produced. So |
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23:54 | going to the spinal cord. And so here the drainage actually we don't |
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24:01 | much about the drainage but we'll come to it. I have another whole |
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24:06 | on the ventricle. So we talk how to get to the spinal |
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24:10 | So hang on to that question. look a little bit before we get |
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24:15 | that at the development of the N. S. And how it |
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24:17 | about. So first of all we three for more deal what I call |
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24:28 | really three developmental layers. The Term the term in the end. |
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24:36 | . Um And so when we have three layers it's kind of a this |
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24:41 | called the neural plate and it looks a plate and then that plate starts |
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24:47 | and it actually closes up and forms tube. So this neural tube formation |
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24:54 | also referred to as no relation. end of term will give rise to |
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25:02 | lining of internal organs. Sir. mezza term will result in skeleton bones |
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25:11 | muscles and ectodermal um will produce nervous and skin skin is the largest organ |
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25:22 | the body. And in the very stages of the pleura potency these cells |
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25:32 | capable of becoming either the skin cell No, no. Uh We have |
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25:38 | research here at U. Of When the skin cells of being isolated |
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25:43 | study to produce the progenitors of the of cells, part of the cells |
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25:49 | neurons. Part of the cells become cells. Uh So here you have |
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25:57 | neural play green when neural group neural fold and then finally neural tube |
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26:06 | surrounded by simple minds here and the crest here this process again is no |
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26:13 | and so much that you're seeing here become the vertebral column and scalable |
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26:22 | So this becomes the C. S. And this becomes a vertebral |
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26:26 | column. Now after you have neural formation and during the neural to information |
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26:35 | can have some miss formations of the and these are rare developmental disorders of |
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26:43 | tube formation. But this process, you think about it, it's a |
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26:49 | complex structure in general. From inception sperm meets the egg and there's new |
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26:58 | generator. What happens is self It means that the father and the |
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27:08 | are not saying that I'm gonna put ear next to this here and then |
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27:12 | gonna do this. I'm gonna shape head like this. It's self assembles |
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27:16 | body. The brain self assembles itself this really complex structure. You have |
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27:21 | have the right environment for it internally externally for this development to take place |
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27:30 | and developmental disorders. And maybe one 1000. So the code for self |
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27:37 | is really strong. It's pretty robust . That means that it's not that |
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27:44 | brains always form perfectly. It's just whatever happens in small differences is robust |
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27:49 | not to cause developmental and other But if you have a condition where |
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28:00 | frontal part, the roster, all of the tube is not folded regularly |
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28:09 | not formed normally. You may have condition you cannot survive as anencephaly, |
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28:16 | know, missing that cerebrum or your cerebrum, cerebellum, cerebellum, uh |
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28:24 | cortex. And in other instances if more carnal aspects of this to get |
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28:36 | during the no relation process, you have a condition that is referred to |
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28:42 | to come about. And that is treatable surgically treatable condition. So uh |
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28:53 | they're rare. What happens? What is that there is a very good |
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29:00 | . Thanks for pointing. God is the spinal cord forms this abnormal growth |
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29:05 | it actually sometimes sticks out of the call. So it has to be |
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29:11 | corrected. And I believe that these days they can diagnose it in the |
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29:16 | . And sometimes even perform the procedure the womb too. Don't quote me |
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29:21 | that. But I believe I read this a little while ago For me |
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29:27 | quite remarkable that you have two cells together form a human body but just |
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29:32 | at this millions of cells folding, each other, shaping itself. And |
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29:39 | does it really well the code is . So once you have the plate |
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29:47 | into tube you have more complexity developing the brain and you have information of |
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29:53 | primary and the secondary vesicles, primary of prison cephalon, forebrain. Mesen |
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30:00 | , birdbrain. Now we're looking at divisions of the future. CMS and |
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30:05 | sufferer for the hind brain. So are the primary. Then with some |
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30:11 | this this this shape here frozen cephalon into this shape and differentiate. So |
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30:19 | is now development and differentiation from the from the tube. Primary secondary. |
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30:26 | you differentiated the talents of phallic diets of phallic these are the optic |
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30:36 | students will have the attachment of the . I telling the catholic vesicles become |
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30:45 | cortex. Don cephalon because the part the brain that we call the |
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30:51 | So if you have the optic stock and these optical vesicles and the optic |
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30:58 | of the edge of the optic cup will form the retina. So anybody |
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31:04 | studies the retina or in optometry or neuroscientists because it's a part of the |
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31:13 | routinely is not that other components of eye ball and the eye, but |
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31:19 | retina is okay, okay. file and cephalon, two cerebral hemispheres |
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31:36 | from talent cephalon dying stuff along starts in the high end brain and the |
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31:45 | starts differentiating. You can see that what looks like one structure in the |
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31:52 | . Eventually you form four structures. is on, on the dorsal |
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32:00 | you're looking on the dorsal side of brain and uh what you're seeing basically |
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32:07 | these structures four structures. One of favorite structures in the brain that referred |
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32:13 | as corporate quadra, gemini, corporal, the body quadrille for gemini |
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32:25 | . If anybody is into linguistics or foreign languages and there's more than two |
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32:30 | three languages and this is also a . You always have to take it |
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32:35 | and cut it in pieces. so um that's how you can understand |
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32:45 | easier. There's roots to the their endings to the words of |
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32:50 | But if you go to the you know corpora, corporal, corporate |
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32:56 | something to do with what location or quadra. Four quadra quadra try or |
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33:08 | try would be three by would be what computer received we have again, |
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33:19 | rasta Raul, no factor involves All coddle dan cephalon cerebral hemisphere. |
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33:30 | for labeling questions don't get stuck on image. This is a different orientation |
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33:36 | the previous slide, just learn what structures are and what you're looking at |
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33:41 | factory bumper front, what's the front ? All that's where I am. |
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33:47 | look in previous slides roster was on opposite side of the slide. So |
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33:52 | learn it just by looking in the but learn the three dimensional structure. |
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33:57 | is still in cephalon. Diane the main divisions. Okay And |
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34:03 | You have the formation of the ventricles two lateral ventricles, the third |
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34:09 | You can see the dyin cephalon further into stahl emus and hypothalamus. Very |
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34:16 | parts of the brain. You have basil tellin cephalon. Then you have |
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34:20 | cerebral cortex, basal tellin cephalon also other cortical areas like temporal lobe. |
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34:27 | have corpus callosum here corpus callosum is major fiber track that inter connects the |
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34:34 | hemispheres, the left and the right . So the communication between hemispheres because |
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34:40 | have contra lateral as I said control movement for example it doesn't mean that |
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34:45 | left hemisphere doesn't get that information and that information. There is a connection |
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34:52 | communication between the hemispheres. You have lot of sub cortical e from the |
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34:59 | cephalon especially from the thalamus. You a lot of projections that are wide |
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35:05 | projections. So these are axons that run from the thalamus into the cortex |
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35:10 | they will also run back from the into the thalamus. These projections are |
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35:16 | to as internal capsule and you will these white matters running basically from diane |
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35:25 | into the cortex from back into the and cephalon and that's how the communication |
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35:30 | happening between the sub cortical parts of brain and the cortex. So if |
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35:35 | look at this brain ship enterprise, have talent, cephalon, dying |
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35:41 | This is another representation. You have based on olfactory bulbs. You have |
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35:47 | cephalon which becomes the following. This the following. This is on the |
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35:52 | side and then you have the hypothalamus you have the textile which forms from |
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36:00 | the brain. Tector means the So again it's this side that detect |
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36:07 | . Then you have the tag momentum this side and the ventral side. |
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36:12 | balham around them. Zeppelin hind brain to serve balham and pawns and then |
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36:19 | smallest longest part here. That's the reminiscent of the spinal cord is called |
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36:24 | medulla oblon gata and then subsequently the cord to the ventricles that you have |
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36:31 | running into the lateral ventricle, the and 4th ventricles and then the whole |
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36:38 | supply goes through the spinal canal into spinal cord. So CSF actually will |
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36:44 | in the spinal cord also has its drainage system. With the interesting part |
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36:50 | is that if you wanted to sample fluid you could tap in to the |
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36:59 | . It's called spinal tap and get sample of service spinal fluid and that |
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37:04 | important especially when you are studying or suspect the brain infection in the cns |
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37:10 | infection of the fluid. So we'll back to that in the sacramento. |
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37:18 | once again now we have the mature with complexity with different parts that we're |
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37:24 | at. And now we're going to learning about these different parts of their |
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37:28 | . South side grooves, gyre, ridges, cortex, the seat of |
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37:35 | and ignition. Or can we think our guts? Well, surely our |
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37:45 | can influence our thinking a lot. But if you disconnect for cortex from |
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37:56 | rest of the body, there isn't left. So if the gut is |
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38:02 | it cannot perceive it without the higher and this the brain you have the |
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38:09 | lobes in the front. You have parietal love and the central selfish that |
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38:16 | the two lobes. Here have a . It'll load in the back. |
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38:20 | is a temporal lobe. This is sort of alum. This is a |
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38:25 | dimensional structure of the ventricles and the is the lateral ventricles. And third |
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38:31 | going into the spinal cord, the dimensional structure that's been cut off in |
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38:37 | sort of the rat and human brain there's still a lot of similarities, |
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38:42 | if we're very different animals structurally There's some basic features that are |
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38:48 | You know, we have Madura have pounds. Uh We have third |
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38:55 | We have talent, cephalon, olfactory that's very small. And they have |
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39:02 | factory but it's very very large. there's certain features that we have again |
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39:08 | have developed a lot better in us the animals so that there are certain |
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39:13 | features that are repeated throughout animal So you can take a piece of |
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39:21 | from an alligator with a lot of here or you can take a piece |
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39:26 | cortex from rat. We also have lot of these here too. And |
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39:29 | you take the piece of its new and you stained it with famous stains |
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39:36 | missile stain or golgi stain you would the parameter will sell ethical denver rides |
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39:41 | a certain layer structure. When you in the rodent you would find the |
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39:46 | or very similar looking phenomenal sauce with certain structure. So there is uh |
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39:55 | in the cells across animals. There redundancy in connectivity in in in between |
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40:06 | animals. And also there's redundancy and that is throughout different cortical areas. |
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40:14 | you can take a plug from the lobe, temporal lobe, frontal lobe |
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40:20 | you will find similar circuits and you find these parameter cells in there as |
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40:26 | . Give Me 1 2nd Place. . Neocortex. New cortex is both |
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40:38 | layered structure and a column of It's found only in mammals. And |
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40:46 | really a structure that organizes all of neuronal inputs and outputs and dictates the |
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40:57 | . The structure dictates the function and function can affect the structure also. |
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41:02 | are synonymous. If you were to neocortex and you were to take it |
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41:07 | occipital temporal loan rat or human you would see a strip layered structure |
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41:18 | so you can see this is a stain and you can very clearly see |
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41:22 | denser bands of cells here and these bands of south means that there are |
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41:29 | packing of the neuronal settlements. But by looking at this corona section through |
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41:37 | cerebral cortex, we can tell that clearly 123423 doesn't have much of a |
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41:46 | boundary, therefore subdivided into abc at five and layer six. So the |
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41:53 | superficial layers one and the deepest layer six. If you were to look |
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42:01 | the cortex and layer structure, you say it has a laminar anatomy. |
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42:07 | then if you were to do certain such as golgi stain or initial |
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42:14 | you would see that these cells are communicating up and down this layered structure |
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42:23 | referred to as a columnist structure. it has columns and this is a |
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42:29 | stain for you which is a Weigert wider stain will specifically stain axons which |
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42:36 | these very clear columnar like connectivity in little Patricks of the neocortex that we're |
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42:44 | at, like I said, you take it from frontal lobe from primary |
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42:52 | cortex in the frontal lobe from the association cortex and parietal lobe from primary |
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43:00 | cortex in the occipital lobe and its large structure. And it's similar in |
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43:07 | arrangement and packing density and it's a different than the overall thickness of the |
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43:13 | york cortex. So neocortex, the letter structures called neo. Because it's |
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43:21 | . This is the hottest latest thing the brain that has formed through |
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43:26 | Six large structure. Remember when we at the hippocampus and we studied hippocampal |
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43:34 | and I said there's excitatory cell that's by all of these inhibitory cells. |
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43:40 | ? I said it's a three layer and it's referred to as our key |
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43:46 | or archaic cortex. So hippocampus is three layer structure in this old cortex |
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43:54 | a cortex. New cortex is six structures. New cortex evolutionarily. It's |
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44:00 | . However, I keep saying that wants to become a cortex too. |
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44:06 | there is, in my opinion uh something very interesting going on in hippocampus |
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44:12 | the connectivity of hippocampus and maybe a years from now hippocampus will be a |
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44:19 | large structure just like the neocortex And it will no longer be called |
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44:24 | cortex, neurons form columns that have response properties within the column. These |
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44:39 | come in different sizes from very small columns and they are like a local |
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44:46 | network. There's many networks involved in a task with this local processing |
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44:53 | You may have multiple columns next to other, processing the same information. |
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44:58 | you have parallel processing or you have redundancy in processing the same information through |
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45:04 | columns. Remember radio glial cells during early development they stretch themselves and become |
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45:12 | a lattice on which neurons climb to their final destinations. So at the |
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45:20 | of the micro column. During early this is a really cool thing. |
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45:24 | gonna be one master mike radio glial that is going to regulate and allow |
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45:31 | neurons to hang on to populate this and adjacent column is going to be |
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45:37 | radio real master south that's going to neurons populate the micro column next to |
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45:43 | . So there's something interesting about the glial cells and the development of these |
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45:49 | columns is a limiting factor. After factor in the destination for neurons but |
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45:54 | factor in the sizing of these columns they're using one lattice to climb across |
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46:01 | one micro column and not that one over which would form the other micro |
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46:09 | comedian. Broad hman, he stained , they studied it, he's famous |
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46:18 | uh he devised side architect tonic Remember you said different functional areas are |
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46:25 | by observing variations in the structure That's not enough. You have to |
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46:29 | the structure itself, you have to the subtypes of cells, you have |
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46:32 | know the connectivity of self, you to know the subtype and as far |
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46:35 | exciting or inhibitory projections or non So this this is somewhat limiting but |
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46:41 | is a huge advantage in looking at brain and organizing the brain based on |
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46:46 | architecture. The other interesting thing is if you use nestle stain you actually |
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46:50 | distinguish between neurons and glia. Remember stain will not reveal the processes the |
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46:56 | anatomy of them. Rights and accents stain all of the cells but it |
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47:01 | be used poor stand to distinguish neurons glia but it can Okay so then |
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47:09 | have different parts of the brain that and by the way we're gonna come |
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47:15 | and study the cortical connectivity in much detail. So this is just introduction |
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47:22 | the sixth layer and calling the You should know these dies. But |
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47:28 | we study the visuals system and I'm sure we're going to get to the |
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47:32 | of the visual system in this But the second section of the course |
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47:36 | try to study the visual system. look into exact circuit connectivity in the |
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47:41 | york cortex. So there will be information coming about new york cortex in |
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47:48 | brain We have areas that are called . Then we have areas that are |
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47:55 | secondary in motor areas and association And those association areas are particularly large |
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48:05 | complex in primate brains. So what we mean by primary area? Primary |
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48:13 | is how much of the brain how much of the brain mass is |
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48:22 | to receiving auditory information. That's what information is. It receives obviously through |
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48:28 | years. But when it gets to cortex, how much of that cortex |
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48:33 | listening, How much of that cortex looking at the stimulus, how much |
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48:40 | that cortex is processing some out of information. So you look at the |
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48:49 | very large part of its brain is to visual information, auditory sensory motor |
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48:57 | then you would say wow in humans visual information and is so small. |
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49:02 | that mean that rats have by far advanced visual system? That's not the |
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49:08 | . It's actually just the opposite is you look at the complexity across the |
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49:15 | here from rat to capture human what seeing in the cat. That visual |
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49:22 | . Overall visual area in red is relatively much smaller to the rest of |
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49:28 | size of the brain than it is rodents. And if you look in |
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49:34 | , that visual area which is primary is even much smaller relatively to the |
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49:42 | of the size of his right, does that mean? Primary you may |
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49:48 | of almost like primal? Not but you can think of the primary |
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49:54 | primal. What I see what I , what I smell what I feel |
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50:03 | areas. Secondary areas, tertiary they're co ordinary areas. In each |
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50:10 | the information becomes more and more There are areas in the brain that |
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50:17 | join the information across different sensory That means that the auditor information is |
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50:26 | meet visual information. It's gonna meet information is gonna meet emotional information is |
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50:33 | meet number information and so on. those areas where these sensory modalities intersect |
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50:43 | get processed in complex ways are called areas. So in these lower |
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50:51 | animals, their primary, what I occupies a lot of their brain. |
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50:57 | humans, it's not what I but it's how do I interpret what |
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51:03 | see? Way more of the brain is dedicated to. How do I |
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51:08 | this primary primal signal? How do join that visual signal with auditor's |
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51:17 | With sensation from my body. So you can see, humans will have |
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51:25 | primary areas and large areas of the . And be dedicated to Association |
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51:34 | two More complex processing of the So it makes this lower or the |
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51:40 | more simple, actually, more more area processing basic information what I |
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51:48 | rather than how do I interpret what see? So, association areas is |
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51:58 | the magic happens. It's where you're happens. It's where your association with |
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52:07 | a certain color. I'm in love I hate the scholar and the |
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52:11 | It's killing me and I hate but I love rock and roll and |
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52:16 | of these things come together. So association areas is where the magic |
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52:25 | . Association areas is what gives us is humans and how we perceive |
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52:33 | We don't perceive things the same way how we interpret things but we don't |
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52:39 | things the same way. There could something that happens factually between two people |
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52:45 | a fact happened and those two people walk away interpreting what happened completely |
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52:53 | And some may say this did not , it's not a fact. How |
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53:00 | that come about? How does that about in anything in life? But |
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53:06 | does come about in any place. you have an argument with a |
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53:10 | No he or she didn't say She said that. No he didn't |
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53:13 | it. You play the phone. , she she said it. So |
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53:18 | happened to you at that time when saying you forgot it or you're interpreting |
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53:23 | differently. So there's all of these things that come into play. But |
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53:28 | areas is what makes us more individual think is more complex. Gives the |
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53:35 | to interpretation. The diversity to our also motor outputs eventually their motor outputs |
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53:42 | speak your right to draw something and or something. And at each station |
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53:47 | primary to secondary to tertiary coronary association , the processing becomes more complex |
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53:59 | So what you see gains a lot context and interpretation and you have parallel |
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54:10 | . So you'll have a perfect example years, two eyes the processing |
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54:17 | some of that information is overlapping with right ear can hear is also with |
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54:22 | left ear Can hear Part of the visual field overlaps with the left eye |
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54:27 | field. So you'll have these parallel streams and then on the micro scale |
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54:32 | have smaller parallel processing streams. But each state station from the I. |
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54:38 | primary visual cortex, secondary to the visual information gains more and more |
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54:45 | more and more complexity until it goes association areas where now it gets |
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54:51 | Co joined with the feeling with the , with the sound and so |
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54:59 | There's a lot of different parts of brain here would like them all. |
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55:06 | spinal cord which is uh missing here the very top is hidden by the |
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55:13 | the slide, major divisions the spinal sacral, lumbar, thoracic, cervical |
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55:19 | stem from the of long palms. midbrain here dot which is the thalamus |
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55:28 | top, hypothalamus below. Basal ganglia an important nucleus in the brain that |
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55:34 | involved in motor command initiation in Yeah, hemispheres here. So this |
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55:42 | cord receives and processes sensor information from joints, muscles of limb and |
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55:52 | Everything that your spinal cord processes is down. That means from here from |
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56:00 | head information inside is processed by the stem and then further up by the |
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56:09 | regions. So spinal cord fields, and spinal cord has motor neurons the |
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56:18 | output to movement of limbs and write. The command comes from the |
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56:25 | , left cortex move my right what would move my right arm. |
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56:33 | for modern urz motor cortex send that to the connections to the spinal cord |
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56:40 | spinal cord said contract this muscle this this muscle relax that I don't relax |
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56:46 | boom. There is a command that from eventually from the modern neurons that |
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56:52 | studied from the spinal cord but it in the cerebral cortex. Brain stem |
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56:59 | well you have a lot of sensor from muscles of the head and |
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57:06 | Motor control of head muscles, sensations the face and head. Brainstem also |
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57:14 | the nuclei that regulate arousal and awareness it has cranial nerve nuclei which you |
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57:21 | learn in this course the cranial nerves sensory and motor information and also in |
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57:28 | brainstem. You have nuclei that are we call them special senses nuclei for |
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57:35 | , balance and taste. Medulla oblon is vital, autonomic functions, breathing |
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57:42 | rate, digestion. You have damaged maduro of long gotta. It can |
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57:47 | deadly because you may lose control of breathing or the heart rate ponds is |
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57:53 | you have a lot of the inter between cerebellum and cerebrum. And so |
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58:00 | have a lot of motor information that crossing in between cerebrum and cerebellum, |
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58:07 | is responsible for force and range of and learning motor skills. So sarah |
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58:16 | is responsible for what we call procedural . Your motor skills or procedures that |
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58:24 | do. What is an example of memory riding a bicycle, it's not |
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58:31 | not facts, you can remember facts the bicycle but knowing that your brakes |
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58:36 | salmon or something else is not gonna you ride the bike just helps you |
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58:42 | . So once you learn how to the bike, do you ever forget |
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58:50 | ? No. That's really interesting about procedural memory is that you can recall |
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58:56 | instantly. And even if you don't a bike for 20 years you can |
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58:59 | down, you're going to be a bit of balance while going there you |
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59:03 | . But try to solve an equation yourself 20 years ago or even five |
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59:10 | ago, that's really way, way more complex, right? And |
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59:17 | not that writing a bicycle, keeping balance and watching everything around is a |
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59:21 | task but the memory encoded for the and the cerebellum is very strong and |
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59:26 | states and it's called procedural memory. we talked about the hippocampus, we |
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59:31 | hippocampus is responsible for semantic memory. there are different types of memories. |
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59:37 | of us are better at remembering facts storytelling and that's a semantic memory. |
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59:43 | some of us had really well developed procedural aspects and very well developed serb |
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59:51 | this muscle memory and performance that athletes do is also involving these brain |
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59:58 | These it's not just building of a then you know, it's it's building |
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60:03 | a muscle but you're if you're a , if you're some pole vaulter or |
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60:08 | else, you know that's that's really and you recall it so it will |
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60:17 | peed uncles. We look at the , we can cut off the cerebellum |
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60:21 | attach the pause here at this particular uncles, it's just the name of |
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60:27 | area, mid brain uh sensory and functions including eye movement and coordination of |
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60:38 | and auditory reflexes. So that structure talked about corporate quadri gemini is responsible |
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60:45 | visual and auditory somewhat of reflexes. you may this information from all over |
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60:57 | nervous system and route to cortex before get into cortex to go through diet |
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61:02 | stuff alone and before things exit out cortex to go through hypothalamus is the |
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61:12 | of the knee thalamus that is responsible economic and voluntary bodily functions. It |
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61:19 | it is somewhat of a neuro endocrine and it's also can influence the glands |
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61:32 | hormones and hormone induced hormone release and functions and hypothalamus is also a part |
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|
61:41 | HP. A. Access if you about it. Hypothalamic pituitary adrenal |
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|
61:52 | hypothalamus to pituitary gland two adrenal is organ and kidneys. Uh So what |
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|
62:11 | that HP access do? It's your axis, it's the cortisol the stress |
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62:17 | control access. And so hypothalamus is in in the stress response and control |
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62:25 | the H. P. A. release of the stress hormone which is |
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62:31 | cerebral hemispheres to have cerebral cortex throughout different hemispheres. When we keep mentioning |
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62:37 | of the nuclei in the cortex are collections of south such as basil ganglia |
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62:44 | as hippocampus which you already know very and function of basal ganglia is coordination |
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62:50 | initiation some of the movement patterns but informs the motor cortex that's performed this |
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62:59 | pattern. Motor cortex says remember this ? Okay you reminded me I'm going |
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63:04 | send the signal, this is the so it's encoded and basal ganglia will |
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63:11 | responsible for initiating and some of these that I'm talking about for campus semantic |
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63:20 | . Magdala is part of our emotional emotional processing. It's also a fear |
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63:28 | linda brain. So these are some the three sort of cortical structures but |
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63:35 | not cortex that you discuss to a or lesser detail throughout the course. |
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63:47 | you're playing tennis and it seems like pretty simple task. But let's see |
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63:54 | needs to happen in the brain in for you to play tennis. Tennis |
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64:00 | flying after you. What happens? see the ball? So the first |
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64:07 | is you see the occipital lobe gets right? You're measuring the speed of |
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64:12 | ball with the rise pre motor How should I approach and hit this |
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64:20 | ? The motor commands right basil gang involved too. The amygdala is also |
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64:28 | just the motion but also part of home state is up keeping regular from |
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64:32 | ecstatic environment. But emotion, emotion important. I want to win this |
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64:38 | . You need to have emotion, need to have motivation to hit a |
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64:42 | shot, right? And maybe great memory in your cerebellum and maybe even |
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64:55 | memory, you know this is my game with this opponent. I'm on |
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65:00 | to I have to win this, know, his name is stone, |
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65:03 | her name. Now you're about ready hit the ball all of a sudden |
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65:10 | parts of the brain kick in. when you're hitting the ball of course |
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65:15 | looking but now a lot of it motor function, execution of that basil |
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65:22 | that initiates the pattern and recall of . Motor pattern says the signal communicates |
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65:27 | motor cortex. The command comes from cortex, hit the ball, you |
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65:33 | hippocampus again, semantic memory is important . Remember that shot, Remember that |
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65:39 | I had when I won that I want to have that feeling |
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65:43 | I want to be a loser. I hit that ball point. So |
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65:50 | is responsible for appropriate exception, which the orientation of your body with respect |
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65:58 | gravity and the objects around you. the net tennis net and the |
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66:04 | Okay, and how you're leaning in that's appropriate exceptions are about them. |
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66:10 | cerebellum is fine tuning of the already motor commands. So the motor command |
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66:19 | hit like this and you're running to the ball and the ball bounces off |
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66:25 | little stone because you're playing on the court and instead of flying straight into |
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66:31 | rock into the racket, it seems be turning slightly this direction. But |
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66:36 | command pattern already initiated the front hand now is what we call the middle |
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66:44 | steps in and says, do the and you return the shot right? |
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66:51 | there's fine tuning and there's adjustments and lot of times cerebellum for that matter |
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66:56 | called the middle management of the murder executions. Racquetball is a great example |
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67:03 | I think of the cerebellum function because has uh wall surrounding it and the |
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67:11 | can bounce and you can put a on the ball in a different way |
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67:15 | you think the ball is going to far, but it actually stops and |
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67:18 | or vice versa. It's bouncing off wall one direction and then something happens |
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67:23 | the curve of the ball and then doing something else. So once the |
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67:29 | is initiated, many adjustments can be , especially in racquetball, you have |
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67:34 | have the brain stem, you have have arousal, you have to have |
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67:38 | , you have to have heart you have to control it. A |
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67:42 | of times. I'm still learning how breathe. Actually it takes a |
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67:46 | very long time to learn how to when you talk and not to choke |
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67:52 | because you're trying to get 15,000 words with one breath and so on or |
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67:58 | you're working out. It's also we're you know have to control your breath |
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68:04 | some of it is conscious and some it is just vital functions but you |
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68:08 | influence them with what you're consciously Alright now we're gonna go into more |
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68:16 | on the brain. Let's see how slides I can cover today. Maybe |
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68:23 | just this slide which shows you more any one of these great exam questions |
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68:32 | labeling. So you may want to some of these like auditor cortex. |
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68:39 | cortex beyond just occipital lobe that you visual cortex that have auditor in the |
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68:45 | lobe. This amount of sensory is right here and the parietal, the |
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68:51 | area of the primary motor cortex. the frontal lobe this is referred to |
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68:55 | pre frontal cortex. There's a gustatory cortex of some of the court assists |
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69:04 | process certain information are not all on surface. And you have to actually |
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69:09 | off some of these salsa and gyrate find a seat for that particular |
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69:16 | Okay and so yeah maybe how many slides we have left? We have |
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69:27 | Uh let's say 45 minutes left. I just like to introduce this slide |
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69:32 | the last slide today. It's a of the thalamus and hypothalamus thalamus here |
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69:42 | . So sub cortical. It's called cortical is below cortex. Hi is |
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69:49 | the following. It's following this information all of the C. N. |
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69:54 | . For a very long time. nuclei which stalinists is huge tolerance is |
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70:01 | a collection of many different nuclei and nucleus and the following. This is |
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70:08 | for specific information processing. So for visual information from the retina comes into |
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70:17 | lateral gene Nicholas nucleus and from lateral of the thalamus it projects into the |
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70:25 | visual cortex. In the occipital lobe information comes into the medial nucleus from |
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70:35 | ears and for medial nucleus that information go into the auditory cortex. In |
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70:42 | temporal lobe it's a matter sensor information the spinal cord will come through the |
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70:51 | column nuclei. I don't need to that to make it smaller and larger |
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71:04 | comes in to the ventral posterior lateral of the thalamus. So that's all |
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71:12 | sensor information and then it goes into amount of sensory cortex. So what |
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71:19 | stalinist stalinist is a collection of nuclei are responsible for different sensory functions that |
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71:27 | going into the cortex and for a time it will stop the thalamus is |
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71:34 | . It's like a relay station. carry the signal from the regiment to |
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71:38 | thalamus. The thalamus passes it on cortex. So like it doesn't do |
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71:43 | just it's too far from the retina the occipital lobe. Primary visual cortex |
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71:47 | thalamus halfway through. Whoever did the . Put the eye here and put |
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71:53 | visual cortex in the back. But think there is a reason for |
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71:58 | Maybe more states can sometimes be You can do more complex inter inter |
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72:03 | in between. So not passive tolerance not passive. What we've learned is |
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72:11 | when the inputs come in from the they're adjusted in the following days when |
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72:15 | inputs coming from the ear cochlea, adjusted in the thalamus the thalamus gates |
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72:21 | modulates the signal flow information. It is interestingly following. This is mostly |
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72:28 | of excitatory cells. There's some inhibitory with this excitatory cells of projection cells |
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72:34 | L. G. M. That project onto the cortex. But the |
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72:39 | following this has this really interesting sheet is referred to as red articular |
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72:47 | It's a sheet that covers the whole and it's a sheet of inhibitor |
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72:54 | Inhibit ourselves that control the activity of thalamus and activity between the thalamus and |
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73:01 | cortex and from the cortex back into followings it's almost like a mesh like |
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73:09 | . Very thin couple of soma Uh So much layer like structure have |
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73:17 | following us is responsible for our dynamic under cream glands and hormones visceral |
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73:26 | body temperature. The blood brain barrier the blood and hypothalamus is pretty |
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73:33 | So hypothalamus sort of your gauge for going on in the blood like the |
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73:39 | . Like some toxins even that can in your blood hypothalamus is gonna start |
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73:45 | to uh it can influence appetite, intake, control sexual activity, lactation |
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73:57 | slow growth as in hormone induced growth your slow growth development. And does |
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74:07 | mean that this is the only part the brain that will regulate appetite or |
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74:14 | activity? No but it's an important and plays a role in these complex |
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74:20 | that we have. Super charismatic Super charismatic nucleus is Located right where |
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74:30 | chi as um happens between the two . So were the two optic nerves |
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74:40 | in. This is optic nerve from eye and optic nerve from that. |
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74:44 | know we stripped off the brain so looking at the cranial nerves. And |
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74:48 | worry we'll come back next lecture and all of the cranial nerves at least |
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74:53 | that are important for us. So is optic nerve. One optic nerve |
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74:59 | left right eye. The component one of the optic nerves is going to |
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75:05 | over in the area where it crosses is known as the optic eye. |
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75:11 | supra cat asthmatic nucleus will be located next to the chi as um. |
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75:20 | and that's super cosmetic nucleus is the body clock regulator or regulator of the |
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75:31 | rhythms. Those are the rhythms that diurnal rhythms. This is why we |
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75:37 | to go to sleep at night and want to wake up sometimes in the |
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75:43 | but light stimulates us to wake up the super asthmatic nucleus will contain certain |
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75:52 | factors and with ambient light and then daylight coming in, they will stimulate |
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75:59 | , light mode or daylight transcription factors molecules. And when the sun starts |
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76:06 | and artificial lights kick in which a spectrum from the sunlight, then the |
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76:13 | happens. This transcription factors that are night take over and they start producing |
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76:20 | and interactions that are important for sleep your night cycle. And it's an |
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76:28 | , very important uh nucleus. And you have traveled overseas and you know |
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76:37 | there's this thing called jetlag, what lag means is that the jet has |
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76:44 | from the United States, let's say . But your body is lagging, |
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76:51 | body is still living in the United clock, Although now you're seven or |
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76:58 | hours ahead of the clock in Or if you're in Asia 12 hours |
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77:04 | of the clock. Right? And the larger that that separation is, |
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77:10 | harder it is for people to So if you go, you know |
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77:15 | Louisiana to florida, it's one hour , you don't really notice it. |
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77:21 | you go from east coast to the coast, its three hour difference, |
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77:27 | actually start noticing it a little But when you cross this kind of |
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77:33 | 56 hour difference and more you really noticing that your body clock is adjusted |
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77:41 | it has a system and then for to adjust it to daylight and night |
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77:46 | for nighttime signals takes time. And lag, you know, for experienced |
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77:51 | is a day or two. Inexperienced a week and then you got to |
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77:55 | home and adjust your time again to your home is at that time. |
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78:03 | , most of the accidents that happened accidents, they typically happen at night |
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78:11 | early, gone kind of a light . That's because third shift of the |
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78:18 | shift is very difficult and as much you train yourself to work at night |
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78:22 | we have a lot of industries, south of here, the energy corridor |
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78:28 | all of the refineries, all of factories that work 24 hours. The |
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78:33 | are very complex, but the human reacts to the environment. The circadian |
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78:38 | is go to sleep and they're like , I'm getting paid to work at |
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78:41 | , so I'm gonna stay awake and circadian clock wins. And humans make |
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78:46 | mistake and you know, something an oil spill or a chemical spill |
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78:51 | something like that. All right, end it here. And when we |
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78:55 | back we're gonna finish talking about major , will review the cranial nerves, |
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79:02 | spinal cord and talk a little bit imaging of the brain function. And |
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79:07 | should conclude our C. N. . And we may start going into |
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79:11 | visual system. Next election. Let check the chat. Okay, somebody |
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79:24 | . Alright, everyone on zoom. see you on Wednesday. Don't stop |
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