| 00:00 | Work. Welcome. This is lecture of Neuroscience and we were discussing some |
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| 00:06 | concepts and important stops along the history development of this very interdisciplinary field of |
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| 00:14 | field of science. It's going to me to change the slides, having |
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| 00:22 | really hard time right now. There go. We talked about ancient |
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| 00:33 | we talked about Roman Empire. We how it was difficult to understand the |
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| 00:39 | anatomy because it was not allowed to human dissections until renaissance times and that's |
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| 00:44 | the development of the modern human. at that point, there is no |
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| 00:50 | that the brain is the most important of the body. Now, the |
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| 00:55 | starts about what are different parts of brain look like. What are they |
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| 01:00 | for in this ventricular localization of the function comes about as suggesting that ventricles |
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| 01:08 | where there's something stored in these There's some fluid, there is some |
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| 01:13 | and the communication in the brain and of distal like motor control of the |
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| 01:19 | and legs is due to the ventricles the specific localization of the brain function |
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| 01:25 | the ventricles. It gets throughout the . But there's also a distinction between |
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| 01:31 | gray matter which is softer, potentially information white matter, which is |
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| 01:36 | We now know these are the myelinated that interconnect neuronal networks. It's harder |
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| 01:42 | nature. Um and is responsible for that information. We have no doubt |
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| 01:49 | modern day and modern neurons that the comes from the cellular networks. We |
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| 01:59 | call this into question once in a , especially when it comes to near |
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| 02:05 | experiences or brief lucidity before death where is no matter to support some of |
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| 02:11 | functions that humans regain very briefly before pass. So, but overall, |
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| 02:18 | the understand it's a complex network of with intricate connectivity in the brain, |
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| 02:26 | what's responsible for your thoughts, for learning, for your mind. But |
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| 02:31 | was called into question and we started about Rene de Carte who came up |
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| 02:38 | a really famous phrase, I think , I am Cogito Ergo and Rene |
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| 02:44 | Carte starts looking at the whole human and also control of the human body |
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| 02:50 | the brain as a fluid mechanical So he is off the impression that |
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| 02:57 | information from the ventricles likely located here communicated through nerves that serve sort of |
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| 03:04 | pipes that pump either the fluids or from those ventricles to control the |
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| 03:11 | He distinguishes between what would be cognitive, reflective behavior versus reflexes and |
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| 03:23 | is illustrated here by this image where child that has never seen a fire |
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| 03:30 | , experienced it and extend the hand the fire and immediately withdraw it reflexively |
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| 03:36 | even thinking about it. The same if you step on a sharp object |
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| 03:40 | as a glass or a nail, step off of it immediately, that's |
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| 03:45 | behavior. A lot of these things handled at the level of the spinal |
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| 03:50 | . Of course, you are consciously that you just step potential in a |
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| 03:53 | object. And then you can execute complex conscious command which is going to |
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| 04:00 | complex motor activities such as going to first aid kit, taking the triple |
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| 04:07 | cream, putting it on the putting a band aid or bandaging it |
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| 04:12 | going to seek medical health, maybe up the phone to call somebody. |
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| 04:20 | , nerves are still viewed as pipes mind is thought to be outside of |
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| 04:26 | matter. Therefore, mind is not part of this gray matter white matter |
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| 04:33 | . It's somewhere out there just like soul. Where is your soul? |
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| 04:44 | is it? Uh So it's sort a soft like somebody may have had |
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| 04:49 | question actually over email from this section that. So, so where they |
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| 04:53 | the mind was out there out And so the connection and formation of |
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| 05:02 | mind is by something that's out there to Rene de card, that gets |
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| 05:09 | through the eyes gets seen, gets to single nucleus pineal gland, it's |
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| 05:18 | centrally within the brain. It's large its structure. And when he looks |
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| 05:23 | the brain, he sees lateral left structure, right side structure, replica |
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| 05:28 | that almost like mirror structures. And sees this pineal gland that is big |
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| 05:36 | it's in the, in the middle , and it's one. So he |
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| 05:39 | that's why I think it's important comes the eyes. Goes to plan of |
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| 05:44 | . That's where you have the Now, the formation of the mind |
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| 05:49 | in contact with this outside energy spirits, whatever you may want to |
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| 05:55 | it and then gets communicated through fluids gasses, move the nerves really cool |
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| 06:05 | . And uh we now know that are not pipes and that they do |
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| 06:14 | pump gasses or pump fluids from the into the rest of the brain or |
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| 06:21 | and the nerves and the periphery arms legs through gasses or fluids. In |
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| 06:28 | 17 eighties, Luigi Galvani works with preparations and he has a rotating static |
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| 06:38 | generator. It's also called a Laden . So he generates electricity and he |
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| 06:45 | a frog that he has dissected and shocks the frog's nerve. And he |
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| 06:51 | that the muscle contracts and then he the frog's muscle and he sees that |
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| 06:57 | muscle also contracts. And to this , we know that the two excitable |
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| 07:03 | in our body from four types of is muscle and nervous tissue. And |
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| 07:11 | now he understands that he replicates that many different animals, he understands now |
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| 07:19 | nerves are not water pipes or channels the cart before him thought. And |
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| 07:25 | nerves are actually electrical conductors. They conduct electricity and they can generate |
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| 07:33 | So the electrical generators and conductors. therefore, you have this overlay image |
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| 07:42 | what one would see typically in the boxes someplace running through your body. |
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| 07:48 | these are the nerves that would be of the nerves running through the body |
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| 07:53 | controlling the muscles and controlling your motor your motor outputs that come from your |
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| 08:00 | cortex. All right. Now, move into the 19th century. In |
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| 08:09 | 19th century, we already understand major of the CNS. We're looking at |
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| 08:15 | central nervous system as comprised of the or cerebral cortex, cerebellum, which |
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| 08:24 | on the back of the brain, brain stem, which essentially holds the |
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| 08:29 | , the stem of the brain, is in your neck area going down |
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| 08:33 | the neck region. And then of , from the cervical here, you |
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| 08:38 | your spinal cord that goes all the as one continuous structure to lumbar two |
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| 08:46 | three and then spreads into the nerves penetrate the lower limbs, have control |
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| 08:52 | the lower limbs, nerves are studied wires. And so there is a |
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| 08:58 | of studies that stimulate the nerves and beautiful system to work with is the |
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| 09:04 | cord, spinal cord has the dorsal of the spinal cord where all of |
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| 09:12 | sensor information is going to come So any information from touching the |
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| 09:17 | anywhere below the neck is going to processed by the spinal fluid. Everything |
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| 09:24 | the neck is gonna get processed by stem and other structures. The nerves |
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| 09:28 | are found there that we call the nerves that we'll study in this course |
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| 09:32 | well. So, but you have dorsal component that forms what is called |
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| 09:38 | root ganglion. There's collections of the soma in this clump right here and |
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| 09:46 | are projections. So they will have peripheral axon in the skin, any |
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| 09:51 | temperature pain, it communicates into the part of the spinal cord which is |
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| 09:58 | is on your back and then the command comes out from the ventral side |
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| 10:04 | the spinal cord, ventral is in front. So this will form the |
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| 10:11 | nerve which will have the dorsal sensory running into the spinal cord. We |
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| 10:17 | the a a sensory inputs. And the ventral side, it will have |
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| 10:24 | neurons that will send their axons through same enveloped nerve bundle to stimulate the |
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| 10:32 | . And we will study the neuromuscular at the beginning. Uh the section |
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| 10:37 | we talk about the s naive transmission well. Now, you have a |
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| 10:42 | where you can stimulate sensory, stimulate , you can ablate it or cut |
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| 10:48 | ventral side or the dorsal side and what repercussions it has. Of |
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| 10:52 | these are animal experiments and they already that there's sensory dorsal carrying information aha |
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| 11:02 | there is ether coming out of the cord into the periphery, motor neuron |
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| 11:08 | that is for muscle control. So we're here at the 19th century, |
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| 11:13 | picking apart, not just looking at nerves, but looking at the structure |
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| 11:18 | the spinal nerves, distinguishing between sensory motor components. And then there is |
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| 11:26 | really interesting science that's huge and it's dominating a lot of brain or neuroscientists |
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| 11:34 | that day. A lot of them relating more to psychology. At the |
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| 11:38 | . We have uh roots of psych uh uh uh uh psychology and |
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| 11:43 | And so, so you have the that is an intersection between biology and |
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| 11:49 | . It's called phrenology. And it about from this Viennese physician Franz Joseph |
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| 11:56 | , from his theories. It's different Galen that we discussed. We discussed |
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| 12:01 | as the person that was using animal dissections to describe human anatomy. And |
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| 12:07 | said it was flawed in part because that. But yo, Joseph Gao |
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| 12:13 | the system of phonology. Uh what after here is specific localization of the |
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| 12:19 | function. Now, an argument ensues all of the brain is responsible for |
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| 12:26 | of the functions. Therefore, if have a piece of the brain on |
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| 12:29 | right side here of the parietal lobe gonna process all of the same functions |
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| 12:34 | that uh piece in the temporal lobe the other side and the piece on |
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| 12:39 | left side in the occipital lobe, all responsible for all the functions. |
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| 12:43 | if you damage a little bit of brain, you lose all of the |
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| 12:46 | to a small degree but to preserve functions to the larger. Well, |
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| 12:52 | is another idea that maybe that's not case that maybe specific areas, specific |
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| 12:59 | in the brain, specific parts of cortex or the lobes are responsible for |
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| 13:04 | function. So, uh or probably lack of any imaging techniques that are |
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| 13:12 | at the time to visualize the bones x-rays have come later or the tissues |
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| 13:19 | come also later with CT scans and scans and pet scans and things like |
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| 13:26 | in the activity. So you cannot any of that. So Franz Joseph |
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| 13:32 | comes up with a system of these tenants that says the brain is the |
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| 13:37 | of the mind. There's no dispute the mind is composed of multiple distinct |
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| 13:42 | faculties while you can be basically very . And they think that that's an |
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| 13:47 | faculty or generosity, for example, they're distinct, these faculties, you |
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| 13:54 | , like uh aggression or generosity or or other things, traits that you |
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| 14:02 | think of an individual because they're He believes that each faculty must have |
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| 14:09 | separate seat or organ in the brain then he says the size of an |
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| 14:16 | , other things being equal is a of its power. So if you |
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| 14:22 | a small muscle, you can lift dumbbell, big muscle, you can |
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| 14:28 | £200 dumbbell size, right? And things being equal is a measure of |
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| 14:36 | power. What does he imply with ? He implies that two things. |
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| 14:43 | of all, that we will have size organs. So if you're generous |
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| 14:50 | that's an innate faculty, your organ generosity is gonna be bigger than other |
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| 14:57 | that may be having other traits. right. So the shape of the |
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| 15:05 | is determined by the development of the organs. As the skull takes its |
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| 15:11 | from the brain, the surface of skull can be read as an accurate |
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| 15:16 | of psychological aptitudes and tendencies. Organs responsible for different intellectual aptitudes and character |
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| 15:31 | . So you're very interested in certain you in features or you know, |
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| 15:36 | mother is so generous, she just everything away. Well, she gave |
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| 15:40 | the house, she gave away the . You know, she's just so |
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| 15:44 | . I don't know, it just everything away. I'm gonna take her |
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| 15:47 | Joseph Gao. Walk in the Joseph office, knock, knock, |
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| 15:53 | You were here for phrenology consultation. , I am sit it. The |
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| 15:59 | sits down and the phrenologist takes out tool. It's not invasive or no |
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| 16:08 | takes out the stool and the stool the size, the circumference, the |
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| 16:14 | , it measures the angles and he the stool all around the skull of |
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| 16:20 | person. And what is he doing those tools? His theory is that |
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| 16:26 | you have that large area for generosity your skull develops, your skull is |
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| 16:34 | . So in any infant and any , it's pretty scary. Actually, |
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| 16:38 | even have these soft spots. One in, in the front because the |
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| 16:42 | plays, have not even fused and about the size of the skull in |
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| 16:46 | infant, the size of a fist and the size of your skulls now |
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| 16:53 | adults. So the bones grow and bones shape themselves, the bones are |
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| 17:00 | and the bones shape themselves around the , neuronal tissue that's underneath it. |
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| 17:07 | that is true. You don't have uh skull plates fused. You'll have |
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| 17:11 | soft spot here and another one in back up until about one years of |
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| 17:16 | . It's pretty scary because you put finger and it's, and it's soft |
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| 17:20 | . It's almost like, can I like poke through it and my finger |
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| 17:24 | gonna go into somebody's brain, you . But no, because we have |
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| 17:28 | meninges covering and protecting the surface. skull does shape itself around the developing |
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| 17:35 | nervous system, nervous tissue. You have heard of a condition hydrocephalus and |
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| 17:41 | feature of that condition are these very , what is typically depicted like alien |
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| 17:47 | . Although we don't know what kind pets aliens had and what kind of |
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| 17:50 | they come in. But let's say large heads. And that's because in |
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| 17:54 | , there's an accumulation of a lot fluid. If it doesn't get drained |
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| 17:58 | early development, that fluid in the starts pushing on the tissue, that |
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| 18:03 | starts pushing on the skull and the starts expanding. So they knew |
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| 18:09 | And so he's taken it too far he would measure people's skulls. And |
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| 18:14 | had all of these areas that they on the skull by measuring sizes and |
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| 18:21 | and ridges on their skull. They that ah ha indeed area, whatever |
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| 18:26 | B is can be noticeably seen here the generosity area. You are |
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| 18:33 | Can't do anything about it, an trait. Your mother will keep giving |
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| 18:36 | all the cows. All right. he drafts up a report. So |
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| 18:42 | a lot of, there's a lot cool things that are going on |
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| 18:45 | There's a lot of cool details that going on here. It's we're really |
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| 18:50 | to understand what part of the brain responsible for what trade or function as |
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| 18:55 | may. And if you go into library in 1848 and 1877 chronological Journal |
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| 19:05 | , Science of Health and it talks the, the, the chronology, |
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| 19:13 | , this magnetism. So there's a bit of uh you know, quackery |
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| 19:18 | on in there. And obviously what has thought of is correct is that |
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| 19:23 | parts of the brain are responsible for functions. However, you cannot read |
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| 19:27 | book by its cover. You cannot a, apart from hydrocephalus condition, |
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| 19:33 | is severe neurological disorder. From looking somebody's skull. You cannot tell their |
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| 19:39 | traits or abilities. You just the size of an organ doesn't really |
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| 19:45 | that you're going to be more power the brain and smarter, I'm a |
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| 19:49 | head and I'm teaching you elephants have heads and much bigger brains than |
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| 19:56 | So that means that they should be the world at the top of the |
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| 20:00 | chain. Maybe we should go back that old image of elephants carrying the |
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| 20:05 | on their shoulders. Uh But that not the case, the size actually |
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| 20:11 | important, but only to a certain , what is more important is the |
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| 20:18 | of that tissue and the complexity of connectivity and interconnectivity and processing ability of |
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| 20:24 | tissue. And so size is This is important. We're pushing the |
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| 20:30 | forward and trying to localize specific functions the brain, but it fails because |
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| 20:36 | looks at the cover, it looks the skull, it doesn't really look |
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| 20:39 | the brain, doesn't look at the tissue. And what we understood early |
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| 20:46 | uh about localization of specific brain functions emerges in the 19th century from the |
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| 20:53 | of doctor Paul Broer, he has patient and that patient expresses or has |
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| 21:01 | aphasia, expressive aphasia is difficulty and inability to convey thoughts through speech or |
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| 21:10 | . You have very difficult time saying , you have difficult time stringing words |
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| 21:15 | into sentence. You have difficult time things down. So it's inevitably linked |
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| 21:22 | a motor function because this is expression your speech. It's not understanding of |
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| 21:27 | speech, it's not listening to the , it's producing the speech or |
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| 21:30 | The speech expresses the patient. And looks in the brain of this patient |
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| 21:35 | mortem art to death and finds a in the left side in the left |
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| 21:42 | in this area right here. And is very puzzled. So he writes |
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| 21:48 | his other colleagues, there's no there's no email, he writes to |
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| 21:52 | other colleagues letters and he says, you have at that point, there |
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| 21:58 | brain banks that scientists could refer Do you have any of you scientists |
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| 22:06 | Europe everywhere we can send the Do you have these cases of expressive |
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| 22:12 | ? Can I have the brain if in the bank? And so soon |
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| 22:16 | , he collects uh examples of several that have all damage to this area |
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| 22:24 | . This area is now called Broca . And all of these patients exhibit |
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| 22:31 | eas so now what he proclaims is we speak with the left hemisphere, |
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| 22:38 | where the speech is located there's no in the right hemisphere, but it's |
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| 22:43 | to damage this area to cause expressive . Now, sometime later, there's |
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| 22:52 | discovery of another area vicus area where damage to Verus area. And the |
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| 22:58 | theme in these studies is what we loss of function studies and the loss |
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| 23:03 | function, inability to express yourself and aphasia, loss of function in receptive |
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| 23:10 | is difficult and inability to understand or read the language, but the patient |
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| 23:21 | hear and see the print but cannot sense. So that's a receptive inability |
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| 23:27 | receive the information. It's not about it, it's about receiving it. |
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| 23:32 | patients that have receptive aphasia, they damage to nicu area. So damage |
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| 23:38 | broker area or loss of function equates expressive aphasia, damage to nicu |
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| 23:45 | loss of function equates to receptive There are a lot of uh significant |
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| 23:54 | of fibers uh that are interconnecting. Aus and Vernis aus. And there |
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| 24:01 | also two more types of aphasia. of them is anomic or amnesia, |
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| 24:06 | . It's the least severe form of where you have difficulty in using the |
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| 24:10 | names for particular objects, people and , nouns and verbs. I think |
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| 24:15 | all have transient, uh anomic uh uh amnesia or amnesia, aphasia at |
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| 24:22 | point. You cannot remember. And like you have that phenomenal the tip |
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| 24:27 | my tongue, like it's some buzzing a neural circuit and you just cannot |
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| 24:31 | that connection to that what we call gram of the neural circuit that processes |
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| 24:38 | is at the tip of your the name of the person or the |
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| 24:41 | or the year or something like And then there is the most severe |
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| 24:45 | of aphasia, that's global aphasia where have damage to multiple language areas and |
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| 24:53 | lose almost all language function. Those both comprehension, ex expression, they |
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| 24:58 | read or write. What we have from this work of the loss of |
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| 25:03 | is there are multiple areas, many that process and produce language. There |
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| 25:10 | areas that are receiving language information, are areas that are expressing that language |
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| 25:15 | between everything else that we're capable of with language and even the thoughts and |
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| 25:20 | new things and the poetry uh that produced by many different parts that are |
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| 25:28 | for language, the same as in occipital lobe, you have the primary |
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| 25:34 | cortex, then we'll study the whole system all the way through the primary |
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| 25:39 | cortex. But we'll also understand that there, there's over 20 different areas |
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| 25:44 | process visual information and they're all slightly for slightly different function of that visual |
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| 25:51 | processing. So this is very revealing it's not necessarily very exact in the |
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| 25:59 | that this has been called somewhat into Barnica Broca area of the location. |
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| 26:06 | much of the speech do you lose course, Broca area is located very |
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| 26:10 | to the primary motor cortex, which in your frontal lobe, which be |
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| 26:15 | be this massive area right here. therefore, it's more tied to |
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| 26:21 | right? But uh there's still a of things that are being investigated and |
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| 26:26 | . But we now understand it's very , many different structures for even one |
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| 26:32 | . And then we come to this here still talking about localization of specific |
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| 26:38 | function at the epicenter of the slide F Gauge, whose story is |
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| 26:47 | really interesting and it's very important for and psychology. Gauge is working as |
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| 26:56 | explosives master. Uh when in the of the 19th century, you have |
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| 27:04 | England railroads that are being laid through mountain ranges there. And what you |
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| 27:09 | to do is you have to flatten ground for the train to pass through |
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| 27:14 | mountains and the crevices in between the . So there's a lot of explosions |
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| 27:19 | the rocks going on. And the who's pictured here is using this |
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| 27:25 | which is really like a metal spare packing the explosives into the rocks and |
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| 27:33 | a controlled explosion to clear the area the railroads. And what happens is |
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| 27:38 | that gets uncontrolled is that accidentally as packing the explosives and explosion happens. |
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| 27:47 | metal bar projects like a bullet out his hands, enters underneath his cheek |
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| 27:56 | here and exits through the top of skull in the frontal lobe here. |
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| 28:05 | This is for gauge, holding that bar that penetrated through his brain. |
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| 28:12 | you would imagine that such a severe brain injury, such a severe trauma |
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| 28:17 | result from the person being dead in person losing many functions, maybe not |
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| 28:22 | able to walk or talk or, of course, he has a loss |
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| 28:27 | function. He cannot see in this because that's been damaged has been |
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| 28:31 | nerves have been cut completely. But months later, he comes back to |
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| 28:37 | for his job again. He's he's talking, he's doing a lot |
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| 28:43 | things that he was doing before this except he cannot control his aggression. |
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| 28:51 | very aggressive. But we now understand you can lose large chunks of the |
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| 28:59 | such as in this case and really an impact on executive function, which |
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| 29:05 | the frontal and prefrontal lobes. They're for having an impact on control of |
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| 29:11 | aggression or behavior. But you are functional member of the society, maybe |
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| 29:16 | little bit dangerous. And so there counseling him traveling from United States to |
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| 29:21 | , killing some people taking the boat to the Gulf of Mexico to Texas |
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| 29:25 | something like that or Florida coming But then there are other counts of |
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| 29:29 | like he wasn't that bad. This exaggerated. So uh a lot of |
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| 29:34 | story isn't known what happens after this , but he is really used as |
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| 29:40 | example for two reasons because there's a of function, huge damage to the |
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| 29:46 | tissue, loss of function is like said, this executive function and control |
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| 29:50 | aggression and behavior. But he also epilepsy. And that's another thing that |
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| 29:59 | now know and we learned that one and we'll talk about epilepsy briefly in |
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| 30:04 | course is one of the major neurological . What we still know to date |
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| 30:09 | traumatic brain injury can cause epilepsy. can lead to severe damage, |
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| 30:19 | loss of neurons, what we call . It can be a continuous chronic |
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| 30:26 | following an injury that eventually causes his in 1860. So an individual that |
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| 30:37 | epilepsy following traumatic brain injury doesn't always it right away. There is what |
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| 30:44 | call a latent period and that latent following the trauma following the data minute |
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| 30:51 | the injury can be a couple of or it can be as long as |
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| 30:56 | decade before an individual develops epilepsy. don't know exactly when he developed |
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| 31:01 | But what we learned is that he 12 years following his accident and he |
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| 31:08 | from a condition that that's called status and status epilepticus is a generalized form |
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| 31:15 | seizure that if it cannot be it will essentially burn the circuits in |
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| 31:21 | uh in the brain and will cause of an individual. So he, |
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| 31:26 | , he, he, he has condition but that condition also doesn't um |
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| 31:33 | his passing 12 years from the date injury. Yes, right now that |
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| 31:43 | like a week. Uh I had great injury. No, this is |
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| 31:48 | great one. So sometimes you can a seizure immediately following a trauma. |
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| 31:55 | in order for you to be as you learn later in the course |
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| 31:59 | epilepsy, one seizure is not In fact, uh a lot of |
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| 32:05 | will have what we call febrile heat induced seizures when their temperature goes |
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| 32:10 | the roof due to infection or flu inflammation. And you know, you're |
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| 32:15 | to take kids, like if they over 104 just rush on, call |
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| 32:20 | nurse and rush on to er, you can't get to er, the |
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| 32:24 | will tell you put them in the bath because you cannot have that temperature |
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| 32:30 | so long. But very likely uh that have the temperature go up, |
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| 32:35 | are also temperature dependent, trauma chemical dependent. So they will have |
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| 32:40 | seizure. It's called febrile seizure. never have a seizure again and they'll |
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| 32:44 | develop epilepsy. So in order for to qualify as epilepsy, you have |
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| 32:49 | have multiple seizures, but you are that following a trauma or an impact |
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| 32:55 | a severe concussion as it happens in sports, you can have a seizure |
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| 33:00 | the spot. It doesn't mean you epilepsy and it's very relevant because you |
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| 33:07 | been hearing all of the discussion, know, now the football playoffs going |
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| 33:11 | , it's really exciting games. But saw last year, you know, |
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| 33:15 | being knocked out in the middle of field had a cardiac uh failure was |
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| 33:21 | to the hospital. There is a tight controls around concussions that happen in |
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| 33:27 | . Now, earlier, it was about get back to fight, you |
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| 33:33 | , get over, get over get back. Now there's a whole |
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| 33:37 | , especially at a more professional especially in football, other contact |
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| 33:42 | rugby, where they will monitor that will take, the vitals will monitor |
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| 33:47 | individual, monitor their ice and say . And sometimes you see people uh |
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| 33:53 | one of the players, uh last , the season was asked to sit |
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| 33:58 | for for many games because he had concussions. And that's another factor. |
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| 34:03 | Another factor is if you have repeated , you're likely to develop a condition |
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| 34:09 | is called chronic traumatic encephalopathy or which has a lot of uh pathology |
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| 34:17 | is similar to Alzheimer's disease. So , you can look at the football |
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| 34:22 | brains that had multiple concussions developed CTE at 30 years of age, their |
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| 34:27 | look like Alzheimer's patients at 90 years age. So, so all good |
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| 34:34 | and some of the things like the clinical stuff we actually introduce and |
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| 34:38 | a little bit about not just on cellular level, but even on the |
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| 34:42 | and even treatments in this course. . Uh Charles Darwin is important to |
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| 34:49 | as one of the people that contributed to the theory of evolution and his |
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| 34:54 | was spectacular, right? He was all around Galapagos Islands, at least |
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| 34:58 | we know what he did is observations animals and their natural environments. And |
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| 35:04 | was studying turtles, he was studying , finches, he was studying um |
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| 35:10 | in the water and he was looking their morphological features such as the beaks |
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| 35:15 | example. And he would say, , it's interesting in Galapagos, you |
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| 35:20 | these islands or the lago of islands is dis in distance. They're located |
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| 35:24 | close to each other but is an very, very diverse and could be |
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| 35:30 | different and, and some islands would all volcanic soil and others. It's |
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| 35:35 | and, and, and so on so forth. So he observes these |
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| 35:39 | on the outside the fins of the , the shapes and the sizes of |
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| 35:44 | beaks, the formation and the movement the turtles on one island versus that |
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| 35:51 | . And the spirit of evolution basically that you have to adapt in order |
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| 35:56 | survive. But what happens is it's only your external organs or external shapes |
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| 36:05 | the beaks or uh fins on the that are being altered is also the |
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| 36:11 | structures that are responsible for having a structure in the brain and function in |
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| 36:16 | brain in order to adapt to that ecosystem on that island. And if |
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| 36:23 | look across species in the in the closest relatives to, to |
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| 36:31 | you have very precisely developed visual cortex it doesn't show much to you |
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| 36:37 | it will show a lot more when study the visual system. But in |
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| 36:42 | , what rodents do is they whisk . And if you look in the |
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| 36:46 | cortex, you will find the structure is referred to as the car |
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| 36:52 | Each one of these barrels corresponds to single wher same number of rows, |
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| 37:00 | , number of whiskers in the same number of barrel rows, a |
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| 37:04 | of barrels in the and we don't this anatomy because guess what? This |
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| 37:13 | survival and procreation depends on whisking around . Doesn't we have facial hair? |
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| 37:21 | we don't do it to touch things feel things around. It's a different |
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| 37:30 | and we don't have that same So this is anatomical map. You |
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| 37:36 | have this whisper mouth in our We don't have a whisper map and |
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| 37:42 | map is a structure on top of structural map. There's going to be |
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| 37:48 | , neuronal activity in neuronal networks. structure and function of the structure and |
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| 37:55 | structure are intertwined. OK. we're getting to the point where a |
|
| 38:04 | of very interesting things happen. We seeing individual cells using microscopes. Uh |
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| 38:12 | I told you that if you take brain and you make a slice of |
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| 38:15 | brain and you just look at it looks translucent. You will see |
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| 38:19 | little bit of gray matter, a bit of white matter, but you |
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| 38:21 | see individual neurons. No, for reasons because it's translucent. And the |
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| 38:27 | reason is at that time or until uh 18 twenties and really about middle |
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| 38:34 | the 19th century, there's no microscopes have high enough resolution to see individual |
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| 38:42 | . And even when those microscopes are , they're looking and they're really not |
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| 38:48 | individual neurons and the game in the is mainly in the stain. So |
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| 38:56 | Golgi pictured here, Clio Golgi is very inquisitive scientist and professor and his |
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| 39:05 | Santiago Ramon Cajal, probably the most neuroscientist definitely in Spain uh Institute of |
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| 39:14 | Monica in Spain, Golgi, Emilio Italian, very inquisitive scientist. What |
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| 39:22 | have is you have photography, how photography done in the 19th century? |
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| 39:31 | know how pictures were taken iphone 13 exist. So you have to have |
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| 39:43 | film, have to expose the you have to go in the dark |
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| 39:50 | , the red light have to develop film. So it exposes the contrast |
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| 39:57 | it was all black and white, gray scale. Basically use a number |
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| 40:02 | chemicals in this process. And you use a number of codes, |
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| 40:08 | preserve it so that when you take photograph, you scratch, it doesn't |
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| 40:12 | come on, it's code. So observes this process, Camellia Gulian and |
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| 40:17 | process is silver nitrates are being used as part of the exposure and the |
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| 40:24 | process of photographs. And he ha let me take it to the |
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| 40:32 | , why not? Let me apply on some brains and see what |
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| 40:38 | And this is what you can do a basic scientist. That's a huge |
|
| 40:43 | . You can have a brain you can see something somewhere else to |
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| 40:46 | , I'm gonna order it. So long as you know, it's legal |
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| 40:49 | , whatever allowed you have it in lab, you can try it. |
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| 40:54 | is really gonna punish you unless you all of your time and money on |
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| 40:57 | for many, many years. But when he does that, he applies |
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| 41:02 | silver nitrate stain. He sees this fraction of neurons pick up the |
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| 41:12 | a fraction 1 to 3% or so all of the neurons. So a |
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| 41:17 | small fraction of all of the neurons the brain will pick up the golden |
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| 41:22 | . And when they get exposed, reveal the entire anatomy with the |
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| 41:27 | with the dendrites and with the accents Ramon Cajal, his student is the |
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| 41:34 | that is sitting and doing these drawings the day and at night and has |
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| 41:40 | very interesting life doing that. And describes here, what we'll study is |
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| 41:46 | retinal projections from the retina some of that become contralateral and cross over into |
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| 41:52 | optic chiasm. Here, others that a lateral from the temporal retina and |
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| 41:58 | to the same side of the Don't worry, you'll know all of |
|
| 42:02 | hippocampus which has different types of This is a structure called the |
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| 42:08 | It looks a little bit like a horse look shaped like a sea |
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| 42:12 | This is a massive cell called Kinji that has over 100,000 inputs on this |
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| 42:19 | tweet. So, Ramonica Hal uses stain and exposes these neurons. And |
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| 42:25 | that same time, there's a raging about reticular theory versus neuron chain, |
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| 42:32 | do chain. If you've taken biology , it's also self theory. What |
|
| 42:38 | the debate? The debate is that reticular theory proponents primarily because the brain |
|
| 42:43 | translucent, it looks like it was kind of one interconnected, especially before |
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| 42:48 | bul stain. The proponents of reticular say that it's all one sensum with |
|
| 42:55 | cytoplasmic envelope and having many many they know millions of nid. It's one |
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| 43:04 | structure enveloped by one cytoplasmic membrane, ? And having cytoplasmic continuity in this |
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| 43:15 | massive network surrounded by one membrane, all a sensation. And of |
|
| 43:23 | Ramon Kahal and Camello Golgi, despite fact that he invented the Golgi |
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| 43:28 | And despite the fact that Golgi stain individual neurons with their processes such as |
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| 43:35 | . And Axons Golgi argues in favor the reticular theory. And his student |
|
| 43:43 | Hall argues in favor of the neuron . He says, no, you're |
|
| 43:50 | . These are discrete individual units that even puts these arrows. And he |
|
| 43:55 | , you know what these are He says these dendrites probably receive information |
|
| 44:02 | this dendritic tree. And then something here which is in the song of |
|
| 44:06 | information gets processed. And then he arrows saying, you know what from |
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| 44:12 | SOMA that information, these are axons information travels through the axons onto the |
|
| 44:19 | cells and adjacent networks. He also that these connections, we don't know |
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| 44:27 | they are yet. We don't have name for them yet. Charles Sherrington |
|
| 44:32 | up with a name synapse points, storm and starts studying the synaptic transmission |
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| 44:41 | understanding the synapse and wins a Nobel in Physiology and Medicine in 1932. |
|
| 44:46 | that, there's a synopsis and he to a Ramonica ha 2030 years before |
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| 44:56 | , these synopsis are not rigid that neurons connect to each other and then |
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| 45:01 | disconnect and maybe they form other So he without knowing introduces this concept |
|
| 45:09 | neuronal plasticity or synaptic plasticity that is important in early development and learning and |
|
| 45:17 | uh ending in and forgetting things as . So OK, what happens? |
|
| 45:27 | disagrees with his boss, but in , together with his boss, they |
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| 45:34 | Nobel Prize in Physiology in medicine. is an important example of progress and |
|
| 45:46 | in science, dogmatism and rigidity in that remains, despite looking in the |
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| 45:53 | and seeing these individual units, it remains. There should be an important |
|
| 45:59 | for you. Let's use A I generation, older people. What is |
|
| 46:03 | thing? A I, I don't to use it. I don't believe |
|
| 46:06 | . You're cheating. Everything should just directly from you. New generation. |
|
| 46:11 | use A I, we are not . We're just helping. It's helping |
|
| 46:15 | to move ahead. It's two different of thought. Oh, so afraid |
|
| 46:19 | A I, no, I'm gonna advantage and use it, you |
|
| 46:22 | the same in science and the same may encounter with your mentors or with |
|
| 46:28 | bosses in the future, you may studying some molecule, some pathway, |
|
| 46:32 | disease and there's going to be an way of dogmatic, maybe not as |
|
| 46:38 | as it used to be 100 years or more. But there's an established |
|
| 46:44 | of doing something and you as a scientist or medical professional or engineer. |
|
| 46:52 | , you know, there's a better and uh it's not like this. |
|
| 46:56 | like this. Actually there's a better can encounter a lot of resistance. |
|
| 47:01 | lot of times when there's a new in science, any science, a |
|
| 47:07 | tries to publish his or her work that work gets peer reviewed. It |
|
| 47:14 | you send it into the journal so cannot just publish work. I have |
|
| 47:19 | experiments. These are my results. are my figures published. No, |
|
| 47:23 | submit it to the journal, journal then contact maybe 10 different scientists |
|
| 47:31 | hey, can you review this The person that submitted the paper doesn't |
|
| 47:36 | who's going to review. It does know even after review sometimes now they |
|
| 47:40 | saying we reviewed it after the especially for the accepted papers. The |
|
| 47:46 | who get rejected still don't say who it, but they review it and |
|
| 47:50 | say no, we get this work 10 years. It's like what you're |
|
| 47:55 | here and it says no, don't believe so that it may take |
|
| 47:58 | years, it may take five years a person just to publish their work |
|
| 48:02 | convince somebody, especially if they're seeing new, something exciting. And uh |
|
| 48:08 | , it, it, it can , it can be difficult. But |
|
| 48:13 | , you know, at that uh Ramona Cajal resists his mentor and |
|
| 48:20 | a Nobel Prize. So you can in disagreement with your mentor. So |
|
| 48:23 | scientific disagreement, not personal, personal work. Usually you have to leave |
|
| 48:28 | line. But uh scientific, you , if it is, if it |
|
| 48:33 | based on peer reviewed, on discoveries your own intelligent thought processing and um |
|
| 48:43 | guessing that you have or intuition or something that you saw that could relate |
|
| 48:48 | it, you know, it's, , it's very important. You can |
|
| 48:52 | be successful and both of them are . Um And Ramonica hal draws these |
|
| 49:01 | , he does not know that neurons generate action potential. So we know |
|
| 49:05 | nerves running into the muscles can generate potentials. But we don't know whether |
|
| 49:09 | individual units can generate action potentials. electricity and he cannot visualize synapses. |
|
| 49:18 | the reason why is because synapses are small. The the the distance physical |
|
| 49:23 | between two neurons is about 20 nanometers space. So at that time, |
|
| 49:27 | don't have enough of the resolution with microscopes to see that spatial resolution that |
|
| 49:34 | of a detail. There is another that has been developed by uh Nel |
|
| 49:47 | Nissel and Niel stain is different from stain. Nile stain will in fact |
|
| 49:53 | all of neurons and all of the missile stain will get picked up by |
|
| 50:00 | A and poly ribosomes which live mostly . So therefore, as you use |
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| 50:09 | stain, all of those elements, and glia will pick up the Nissel |
|
| 50:13 | will expose their SOMA really well, it will not reveal the precise morphology |
|
| 50:21 | the processes such as dendrites and axons a Golgi stain would. Uh So |
|
| 50:29 | is really good for looking at the of the location of the packing densities |
|
| 50:36 | you see these darker bands. That that the cells are clamp up here |
|
| 50:41 | located closer to each other in It's really good method to see layers |
|
| 50:47 | these cells. And Trian Broman, Brodman is using missile stain and it's |
|
| 50:55 | it, cutting the brain into little and pieces and is using this stain |
|
| 51:01 | this outlining structure. The orientation uh hacking densities of neurons in the brain |
|
| 51:13 | said that we have to look at brain here. What we now call |
|
| 51:17 | broad areas because as I said, and function are interdependent on each |
|
| 51:24 | So, so this is the only we can really understand if we can |
|
| 51:27 | understanding the packing deads and these orientation later connectivity of these neuronal networks. |
|
| 51:35 | they are called cy architectonic methods. different functional areas would be determined by |
|
| 51:42 | underlying structure or the anatomy and packing of these cells and their orientations throughout |
|
| 51:48 | brain. So we cannot see synopsis modern day ST standard life microscope can |
|
| 51:59 | 0.1 micrometer. Does that mean anything you? How big are neurons anybody |
|
| 52:17 | 10 micrometers? They can be as smaller, it can be much, |
|
| 52:21 | larger but average about 10 micros of . So processes can be way way |
|
| 52:29 | of your processes. Some can be others can travel very far distances. |
|
| 52:37 | is one millimeter? How many micrometers in one millimeter patrick? Where's the |
|
| 53:03 | ? Right? 1000 micrometers? So you have 10 micrometers in diameter |
|
| 53:09 | these neurons and the space between two that have the synapsis talking to each |
|
| 53:21 | . These are my two neurons with so much this space here it's 29 |
|
| 53:30 | . So even today, 200 years , we still using light standard light |
|
| 53:38 | are short of having that spatial resolution see 20 nanometer space because we're processing |
|
| 53:44 | 1 to 1 micrometers. OK. right. Now, what do we |
|
| 53:55 | in order to see the spaces? need an electron microscope. It's a |
|
| 54:00 | different. Most of you are familiar the standard light microscope, but an |
|
| 54:06 | microscope, you have to go in separate room. It's a big piece |
|
| 54:10 | equipment and has a resolution of 0.1 boom. Now, we can see |
|
| 54:15 | synopsis. Now, Ramonica Hall can to everybody but that comes about uh |
|
| 54:21 | the middle of the 20th century. it's a little too late for him |
|
| 54:25 | visualize it. Another important technique that introduced for visualizing neu neurons and neuroscience |
|
| 54:34 | infrared imaging using infrared cameras. So was a setup that I was running |
|
| 54:41 | actively for many years at the University Houston here where you have a brain |
|
| 54:46 | that gets placed right here underneath the lenses. This is your eye |
|
| 54:52 | And so if you looked in you wouldn't see anything but with a |
|
| 54:57 | light and a set of filters and that information from the slide over here |
|
| 55:07 | there's a little green light just for illustration purposes that information travels through the |
|
| 55:12 | of mirrors into the back camera here is an infrared camera. And that |
|
| 55:19 | camera is connected to a monitor. when you look in the monitor without |
|
| 55:26 | stain, you can visualize individual And this is a very common |
|
| 55:32 | infrared visualization and doing neurophysiological studies or studies where you have a microelectrode and |
|
| 55:40 | study the action potential some resting number potential. Later in this course, |
|
| 55:45 | have a micro electrode and that microelectrode typically the tip of that micro electrode |
|
| 55:52 | typically on the order of one a to one micrometer where we can target |
|
| 56:00 | neurons. So we don't have to in the brain. We can visualize |
|
| 56:05 | neurons. You have to have infrared , we can visualize their selma and |
|
| 56:11 | pretty well but not to the same . And to the same great detail |
|
| 56:16 | Gogi stain would reveal it still. it's not used to describe the morphology |
|
| 56:21 | the cell, but rather to visualize the cells in specific brain structures |
|
| 56:27 | um target them with the micro Since we have more powerful tools to |
|
| 56:37 | neurons and to visualize synapses in these , we understand that dendrites contain these |
|
| 56:45 | specialized protrusions that we call dendritic And this is where most of the |
|
| 56:52 | between neurons from one neuron to the happens is by contacting these dendritic spines |
|
| 56:58 | this dendritic shaft and it can be of spines in some instances, tens |
|
| 57:04 | thousands of spines and tens of thousands synapses formed on a single neuron. |
|
| 57:09 | is just a fragment of a dendrite a single neuron with its dendritic |
|
| 57:17 | If you look here at the electron , dem is dendrite, not |
|
| 57:24 | it's dendrite. This is mitochondria This is postsynaptic density. So these |
|
| 57:30 | will contain postsynaptic densities of postsynaptic receptors they're directly physically juxtaposed to these red |
|
| 57:40 | that are axons. And as you see inside the red axons, you |
|
| 57:45 | these red round organelle sort of vesicles are filled with neurotransmitter. So they |
|
| 57:52 | be fused with a plasma membrane here the Axion of one neuron releasing that |
|
| 57:59 | in that tiny 20 nanometer space. on the other side, on the |
|
| 58:05 | spin a posy nap density receptors that bind that chemical causing a posy response |
|
| 58:11 | the cell. And these dendritic spines in many different shapes. There are |
|
| 58:18 | that I described here study then spine the mushroom shaped spine. This one |
|
| 58:25 | here. So there are some certain shapes in these spines and they're |
|
| 58:30 | very important in the early development especially throughout the adult life and for normal |
|
| 58:39 | function as a whole. And we'll what can happen if you have a |
|
| 58:44 | in the anatomy or loss of dendritic , it can lead to pretty severe |
|
| 58:49 | conditions, developmental conditions, what we in modern day neuroscience. So today |
|
| 58:57 | the levels that we can study are vast, we can study individual |
|
| 59:04 | we can study individual molecules, we image individual molecules of individual cells, |
|
| 59:11 | can sequence RNAs from individual cells. A seek and sort them and tag |
|
| 59:17 | with different tags. We understand pretty the anatomy of neurons and their |
|
| 59:23 | although it's still ongoing war probably And we also have a view of |
|
| 59:32 | brain activity noninvasively at the clinical So what do you have here is |
|
| 59:41 | of human brain as a person is at words, listening to words, |
|
| 59:47 | , words or thinking of words. are positron and mission tomography or pet |
|
| 59:54 | . Pet scans can show indirect activity neurons but we are imaging neuronal activity |
|
| 60:02 | . So no longer have to open skull. The person just like with |
|
| 60:06 | MRI, the pet scan goes into circular tube in the hospital or clinic |
|
| 60:14 | their brain or their bodies get You can ask people to do different |
|
| 60:19 | , think of words, speak words image their brain activity. So we |
|
| 60:23 | not have the resolution of single We cannot image single neurons, we |
|
| 60:28 | image neuronal networks being active. And can see that very distinct areas of |
|
| 60:35 | brain are activated for distinct functions. as it concerns the speech, |
|
| 60:41 | speaking and thinking of the words we these brain maps. A brain activity |
|
| 60:48 | or brain maps sometimes also referred to brain waves because they travel through the |
|
| 60:54 | networks can virtual reality change the We have of course, imaging |
|
| 61:02 | pet scans F MRI that we study in the course. A great way |
|
| 61:07 | confirm noninvasively specific localizations of brain functions as looking at the words versus writing |
|
| 61:15 | . Each function is subserve by more one neural pathway. We know that |
|
| 61:19 | is a redundancy in process and we two eyes, two years, there's |
|
| 61:22 | lot of redundancy where our sensors are . And even the processing of that |
|
| 61:27 | information is further diverged into different lines processing that information. For speech. |
|
| 61:34 | talked about 20 different areas. So have to take out big, big |
|
| 61:38 | of left hemisphere. In order to lose speech, you have redundancy when |
|
| 61:43 | pathway is damaged, there's plasticity that that neurons can reconnect in different |
|
| 61:50 | And when they reconnect, they are uh compensating for the loss of |
|
| 61:59 | And a very broad sense of somebody's one sense, they can't hear |
|
| 62:04 | their senses of smell, their senses touch or vision might be heightened. |
|
| 62:13 | reconfiguration of the brain that happened to certain extent. Although there's no regeneration |
|
| 62:20 | lost neurons in the CNS, there a regeneration of peripheral nerves and that's |
|
| 62:26 | because they're in different environment. So grain processing is both cereal and |
|
| 62:35 | in parallel redundancy repetition. In hierarchically more complex. What your eye |
|
| 62:43 | is not the picture of the south wall that you form in the |
|
| 62:48 | That information from retinol network, it processed to a certain extent gets sent |
|
| 62:53 | a higher order centers and the thalamus processed there gets sent to the higher |
|
| 62:58 | centers hierarchically making that information more more complex and also more holistic to |
|
| 63:06 | you form the final image of the world, such processing appears introspectively seamless |
|
| 63:13 | us. And also know that A is based on neural networks, virtual |
|
| 63:19 | can definitely affect our brains can affect brain maps. Here is an image |
|
| 63:25 | with virtual reality or no virtual So you sit in front of two |
|
| 63:29 | screen and you do the snowballs at , at the snowman here and they |
|
| 63:35 | and this is the image without no reality. And then you place an |
|
| 63:39 | within the virtual reality where they have actually sort of clicking the mouse being |
|
| 63:43 | this three dimensional world and it changes brain map for the same function. |
|
| 63:51 | yes, this immersion of artificial enhanced reality or augmented reality virtual reality |
|
| 64:00 | A I are very, very interesting there are some interesting thoughts that are |
|
| 64:05 | in the field that we refer to meta. And that's not because of |
|
| 64:10 | , it's because of meta as a in general. Meta pseudo says patients |
|
| 64:15 | have inflammation, they have pain and lot of heat. You can place |
|
| 64:21 | in virtual reality in the snow and and they actually measurable decrease in the |
|
| 64:28 | and inflammation and in their body or areas. So there's definitely interaction |
|
| 64:35 | Uh And it's all, it's all us. Now. I was just |
|
| 64:39 | to a program about the new uh . I guess iphone doesn't want to |
|
| 64:45 | them headsets, but new headsets that bringing some of these elements into everyday |
|
| 64:51 | , not affordable right now for most the people, but soon will be |
|
| 64:56 | . Well, there's a few more about the kind of a where you |
|
| 65:00 | go with Neuroscience. I'm gonna leave here today and we'll come back, |
|
| 65:04 | discuss a couple of these slides before plunge into the neurons and glia |
|
| 65:10 | So again, thank you for being . Appreciate it. I'll see everyone |
|
| 65:14 | |
|
