| 00:00 | Recording in progress. This is lecture of neuroscience and we stopped last lecture |
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| 00:09 | about U cranial nerves that I just . Again, the important ones for |
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| 00:16 | . Now, olfactory optic ocular motor and vague ran nerves. Uh So |
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| 00:29 | is a separate slide presentation on the nerves and the pneumonic by which you |
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| 00:34 | remember them. And you can also up different other mnemonics that are available |
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| 00:40 | and in some books and create their pneumonic to remember the order and to |
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| 00:46 | these uh sensory or motor and potentially function. Because factor is for whole |
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| 00:53 | . We already talked about it very when we touched upon COVID-19 infections very |
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| 00:59 | . It was actually on that slide optic because we will cover the visual |
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| 01:05 | . So we will start talking about comprises the optic nerve, which are |
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| 01:09 | axons of retinal ganglion cells from the ocular motor because it's motor and it's |
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| 01:19 | in the nerve itself, what it moves the eye Trigeminal # five because |
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| 01:27 | want you to be able to recognize nerve stalk. And I want you |
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| 01:33 | be able to distinguish it from optic , optic and the track. Uh |
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| 01:42 | are the two largest most prominent cranial that you would see if you were |
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| 01:46 | expose the brain stem. This to la coa. Number eight, it |
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| 01:54 | what it does or at least it the source of that nerve vestibular apparatus |
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| 02:01 | cochlea. So vestibular cochlear, but talk about the auditory system. So |
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| 02:07 | the nerve that carries information or sound the cochlear component of that. In |
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| 02:15 | , uh vagas 10, we discovered Coline by stimulating vagus nerve onto a |
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| 02:23 | heart. That's an important thing to . Also, it runs extensively throughout |
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| 02:30 | body, innervating the heart and many organs. It's really the most extensive |
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| 02:36 | innervation wise nerve throughout the bottom. it's important to know it also important |
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| 02:42 | remember that when of the lowest stimulated nerve, he saw that the heart |
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| 02:47 | slowed down, although the cty colon a neurotransmitter. And when we studied |
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| 02:54 | junction, this is also heart is muscle. But when we started the |
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| 03:02 | muscle junction, you know, muscular , we talked about acetylcholine as being |
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| 03:09 | a. So don't lose track of fact that all of these things, |
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| 03:14 | things and nerves and uh what they in neurotransmission. It's still a part |
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| 03:22 | the larger picture of the nervous system the chemical electrochemical neural transmission in the |
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| 03:30 | that C MS looking in the spinal , spinal cord is subdivided into |
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| 03:38 | cervical thoracic lumber and sacred in between vertebrae on each side, on the |
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| 03:49 | side and the right side, you a spinal, that spinal nerve on |
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| 03:55 | side is comprised of dorsal Logan axons also motor neuron axons. So those |
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| 04:05 | the gang would be a or inputs motor neurons would be ears or |
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| 04:10 | but they all form that one uh spinal nerve on the lobe that then |
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| 04:17 | itself accordingly. So the, the nerves will take care of the thorax |
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| 04:24 | . The cervical nerves will take care the uh neck area. So you |
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| 04:31 | vertebra, you have C one vertebra C seven. That means that there |
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| 04:38 | seven cervical vertebrae, there are 12 . So you have T one to |
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| 04:46 | 12, there are five, number 13 L five, There's photograph |
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| 04:54 | S one with a shell of the . So if you look again in |
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| 05:06 | each vertebra, you have a a spinal nerve that's associated with |
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| 05:11 | So, C one will have first c uh there's nerve on top, |
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| 05:18 | actually eight cervical nerves versus seven cervical . Right now. Uh the spinal |
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| 05:28 | proper, if you look at the of the spinal cord, proper Ends |
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| 05:35 | one continuous proper structure in about L L 3. And by the |
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| 05:41 | a lot of times you will hear somebody has an injury in the spine |
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| 05:46 | the neck, they'll say oh, have a disc in T four, |
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| 05:49 | five. That's what it means. I have a nerve pie between C |
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| 05:55 | and C three. In this it means that you have a nerve |
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| 06:00 | between cervical vertebra two and cervical vertebra . And where are the nerves that |
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| 06:08 | get pinched in the neck? Between and three? It would be affecting |
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| 06:12 | neck and also the, the shoulder the arm. For example, would |
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| 06:19 | move lower to the short thoracic area nerves? Here would be involved in |
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| 06:25 | information from the thorax, both the and motor information, spinal cord preference |
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| 06:33 | L two L three. From that onward, it becomes ana as |
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| 06:43 | as in or the tail and quina an equestrian. So a horse's tail |
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| 06:57 | Latin called it when now spinal for splits into these fibers and still innervate |
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| 07:05 | respective areas all the way down to toes. Uh That is important clinically |
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| 07:14 | if somebody has an infection in the , it is very likely that infection |
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| 07:23 | it is the case typically is in cerebrospinal fluid. So think about how |
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| 07:31 | you draw cerebrospinal fluid from an You're not talking about blood, you're |
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| 07:37 | about getting inside ventricles potentially because this where rubrospinal fluid is. And one |
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| 07:45 | the best places to draw without Obviously, if you have to draw |
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| 07:50 | from lateral ventricles or the or the the or the third ventricle, you |
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| 07:56 | have to penetrate through the brain So typically people do what is called |
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| 08:02 | spinal tap. A spinal tap is you tap in to the area of |
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| 08:09 | spine to sample cerebra spinal fluid. you can draw a little bit of |
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| 08:15 | cerebral spinal fluid and whatever you find that cerebrospinal fluid, for example, |
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| 08:22 | meningitis infection, you suspect a a person, an adult has mening |
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| 08:30 | infection. By that virtue, you be able, it's an infection of |
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| 08:35 | brain should be able to find the agents in the spinal fluid. So |
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| 08:44 | confirm, you would have to draw serious spinal fluid and I will show |
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| 08:51 | the presence of mano Coco and let's it can be viral or bacterial in |
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| 08:57 | case of London Jarvis. So you put a soft needle right below two |
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| 09:03 | three below the spinal cord proper in the virus and try to sample some |
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| 09:09 | the spinal fluid. Also for anesthesia , during the birthing process. When |
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| 09:17 | female is giving birth to a it is typically very painful and the |
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| 09:27 | and the displacement, physical displacement of the body parts is very painful. |
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| 09:35 | now there's some dual anesthesia that is and typically, again, it's given |
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| 09:42 | this lumber level, the low spinal proper so that it doesn't spread and |
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| 09:49 | anesthetize the rest of the upper which rather takes away the the, |
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| 09:55 | pain, the feeling in the low of the body that's responsible for |
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| 10:01 | the muscles that are contracting and that's most of the pain is. Was |
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| 10:05 | often. Uh women that get the anesthesia, they also cannot move their |
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| 10:13 | because it can affect the, the lower extremities and it not, |
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| 10:18 | move them forever. It's just for couple of hours as anesthesia kicks in |
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| 10:22 | then basically the birth happens and anesthesia off. Yeah. Now this is |
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| 10:30 | components of the spinal cord and the nerves. Again, one spinal nerve |
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| 10:35 | between each vertebra is comprised of the reg gari component and the motor nerve |
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| 10:41 | component. Uh If you look at anatomy of the final cord, it's |
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| 10:47 | of a you think that sometimes people it like a maybe butterfly inside the |
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| 10:55 | cord or sometimes it's referred to as . So everything that's dark here that |
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| 11:01 | seeing, this is the gray gray matter or surrounding white matter are |
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| 11:09 | axons. Those are the ascending and axons. Ascending information will be mostly |
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| 11:16 | through dorsal columns right here on the side of the, of the spinal |
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| 11:22 | . That means that all of the from your, from your to from |
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| 11:30 | neck area is carried into the dorsal and it's carried up that column. |
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| 11:38 | lower extremities, it goes into the column. Those fibers are running up |
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| 11:42 | spinal cord to wherever they are going , which is going to be eventually |
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| 11:48 | to the neocortex and not a sensory . And the way it's going to |
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| 11:54 | the Methalen and some other things that will learn when we study this amount |
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| 11:58 | sensory system. So you have these horns in the back, dorsal horns |
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| 12:04 | where you have the uh location of , of the SOMA. That's where |
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| 12:10 | inputs also coming in contacting motor neurons contacting into neurons that are located |
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| 12:19 | Ventral horn will contain a lot of so of the motor numbers and that's |
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| 12:24 | the output comes out of the motor uh uh in the ventral. So |
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| 12:29 | comes in the dorsal side climbs it gets processed through the SOMA cell |
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| 12:34 | and comes out on the ventral So you have the ventral horn and |
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| 12:40 | have the ventral column, then you the lateral column which is on, |
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| 12:46 | , on, on both sides, . And some people would also designate |
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| 12:53 | as a lateral horn. It's another of a gray matter of division within |
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| 12:59 | spinal cord. It's protected by the protective meninges that we talked about. |
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| 13:04 | is the ventral side and the back the dorsal side. So the major |
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| 13:11 | information is sensory information that means touch heat, pain, itch mosquito |
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| 13:20 | ok. That goes into the spinal , dorsal organum and is carried out |
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| 13:27 | the ascending the sensory pathways and mostly dorsal colum. Uh path is |
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| 13:35 | there is one pathway here, a guess where it originates in the |
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| 13:42 | guess where it is traveling the Ok. So from spine to |
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| 13:47 | Ok. So these are the ascending package. Now, there's a lot |
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| 13:55 | descending motor pathways. So everything the down, those are motor pathways. |
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| 14:01 | the sensor information, somebody touched you up the dorsal column informs, informs |
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| 14:09 | Alaus informs the cortex. You have perception of somebody stopping you on the |
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| 14:15 | . What are you gonna do You're gonna produce a motor command. |
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| 14:20 | then it's gonna produce the motor command the motor cortex and through the descending |
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| 14:27 | . And there are many different descending . I don't want you to know |
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| 14:30 | for the exam, but I want to know the ascending dorsal column because |
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| 14:34 | a major sensory pathway. We study part of this amount of sensory |
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| 14:39 | But this corticospinal tract ribo spinal car the jewelry ridiculous spinal tract, tectospinal |
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| 14:47 | , different origins ending up vestibular spinal . And again, some of them |
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| 14:53 | say, indicate what they do. tibula spinal tract is important for vestibular |
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| 14:59 | . Why is that important for spinal and motor output? Because it's important |
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| 15:03 | your posture and gait and what your is doing with the motor output. |
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| 15:08 | all of these are different motor out . So everything is a sensing, |
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| 15:12 | sensory, everything descending is motor. once your cortex makes, makes that |
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| 15:19 | , hey, somebody tapping on the up, you're gonna turn and shake |
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| 15:22 | hand. That command comes from your travels down into the spinal cord, |
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| 15:28 | adjusted potentially by cerebellum. And then motor neurons activate the movement of the |
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| 15:36 | , the contraction of the muscles on intent to shake somebody's hand. |
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| 15:42 | We have autonomic peripheral nervous system, we don't spend much time talking about |
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| 15:48 | we will spend a little bit of talking about the imaging of the |
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| 15:52 | Now, most of you are familiar imaging and as far as x-rays, |
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| 15:58 | you go to a dentist's office, do an x-ray if you want uh |
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| 16:05 | years ago. They were kind of not as advanced as 10 years |
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| 16:10 | 10 years from now, there will even more advanced, but you get |
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| 16:13 | x-ray done and it shows you your and it shows the cavities and it |
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| 16:21 | any fillings, any crowns you have it shows something around it. So |
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| 16:27 | focus there is the bone structure or heart structure that that starts. |
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| 16:33 | we are here uh and neuroscientists and interested in imaging, first of all |
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| 16:39 | tissue and second of all, we're in imaging brain activity on that brain |
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| 16:48 | . So, a more advanced uh imaging that you have these days is |
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| 16:54 | T of computer tomography. It can pretty well. Between the soft tissue |
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| 17:00 | the fluid filled gaps or tissues or and, and the bone structure |
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| 17:07 | And it's a sophisticated three dimensional It still uses x-ray beams, But |
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| 17:14 | can be in three dimensions. It really nicely recreate an area of interest |
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| 17:20 | three dimensions by doing these x-rays at planes or slices we call them and |
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| 17:28 | up to hundreds, 200 300 slices a small area of the brain. |
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| 17:34 | example, that will reveal a lot what's happening in there with a certain |
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| 17:40 | on the on the spatial resolution. you also hear a Mara or magnetic |
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| 17:47 | of injury. And magnetic resonance imaging not use x-ray depending on the technology |
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| 18:00 | it. And the power uh of that are being used for magnetic magnetic |
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| 18:08 | imaging. Uh MRI may have more than C T you're looking there at |
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| 18:19 | spin and resonance of the of the atoms. It's based partly on on |
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| 18:29 | physics. It is actually based on physics and some parts of quantum |
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| 18:34 | we we can't really explain very well there is a different spin on the |
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| 18:39 | atoms and MRI. So MRI again , will reveal really well the soft |
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| 18:48 | like the brain tissue, different parts that you're imaging and you can see |
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| 18:56 | lot but neither one of these techniques C T scans or MRI reveal anything |
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| 19:07 | the function. It is all about structure of the bone structure of the |
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| 19:14 | . How big is the cyst is uh uh cancer's growth in the in |
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| 19:19 | brain? Right. So it's all structure we're interested in imaging function. |
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| 19:29 | when we talked about uh experimental neuroscience , for example, when we talked |
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| 19:34 | neural transmission, I brought up this imaging technique and they said, oh |
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| 19:39 | are calcium sensitive dye. So you image fluxes of calcium. We also |
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| 19:46 | , oh you can image single you can record from single cells. |
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| 19:51 | have very high resolution with different But now you're placed in a clinical |
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| 19:58 | where a patient comes in and says have this tremendous headache and the head |
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| 20:03 | is helping me. Uh an x-ray not showing much. I'm starting to |
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| 20:09 | seizures. You don't have the ability put an electrode inside their brain. |
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| 20:15 | me just check real quick, open skull, put an electrode, take |
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| 20:21 | recording, send them home, you it doesn't exist. So what, |
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| 20:27 | do you wanna do? And what you do? You can do noninvasive |
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| 20:32 | techniques. And those are pat which poor AIS to tomography and F M |
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| 20:39 | and C T and and C T MRI are noninvasive meaning that that you |
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| 20:47 | placed in the machine. The machine a scan of U C T scan |
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| 20:51 | MRI which is a more complex OK? But uh during it's non |
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| 20:59 | , nobody's putting an electrode inside your , opening your skull or anything of |
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| 21:04 | sort. But we want to know function so that patient was having |
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| 21:11 | for example. And maybe there's something the function of that area or maybe |
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| 21:18 | abnormal growth and there's abnormal activity around area. To me, activity of |
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| 21:23 | brain you need pattern am active neurons demand more blood to be supplied to |
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| 21:31 | active area of the brain. So we saw from uh lecture one or |
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| 21:35 | images, we said, look at brain maps that show a person is |
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| 21:40 | at the words and their exhibit lobe activated and we saw it as a |
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| 21:43 | map of the exhibit lobe. Then said the person is reading uh uh |
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| 21:49 | mean looking at the words, the is thinking about the words and there |
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| 21:52 | a different map that was activated, was activity map. Those were pet |
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| 21:57 | measurements of brain activity. And because active regions are the ones that are |
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| 22:03 | in looking, they're gonna be demanding oxygen, they're gonna be demanding more |
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| 22:09 | and they're gonna be demanding more The cells are increasing their metabolism, |
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| 22:17 | metabolism in the areas that are active a particular task. And that's how |
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| 22:22 | have these regional brain activity mass that can see on the pet scans. |
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| 22:27 | can see them with F MRI MRI is hydrogen atom one proton. |
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| 22:34 | goes between high energy or low energy . The frequency at which low state |
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| 22:40 | absorb energy is called resonant frequencies. this bouncing between high and low state |
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| 22:48 | the resonance frequencies. So that's where have the F and R F is |
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| 22:57 | R is resonant. So F MRI is functional magnetic resonance imaging and radio |
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| 23:07 | get emitted by protons that can then collected by very sophisticated uh electromagnetic |
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| 23:18 | So for pet scan, for pet , you have positive emission tomography. |
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| 23:28 | if you want to image with pet a subject, the person or patient |
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| 23:35 | injected with radioactively labeled solution with positively ions. It's I V injection. |
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| 23:48 | people say, and they a lot times don't know but these procedures are |
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| 23:55 | pretty uh difficult on many patients. not the same as x-ray. So |
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| 24:04 | not like you stand and the machine around you and oh, you |
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| 24:08 | we'll have to repeat this. Oh know, five minutes later, 10 |
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| 24:11 | later you're out that scan, you injected into bloodstreams with radioactive label. |
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| 24:19 | now are radioactive, radioactive. And you have to sit there for |
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| 24:29 | half an hour, please. And you sit there for half an |
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| 24:34 | you cannot be in the presence of individual because you are radioactive. |
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| 24:41 | Literally. So you wait a half hour and then you go into these |
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| 24:49 | under these machines and depending now we're about the brain. So your head |
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| 24:54 | into this machine and a lot of may have issues with it. |
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| 24:59 | first of all, the actual injection radioactive label, what happens to radioactive |
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| 25:05 | to these isotopes? They get they get processed, they get filtered |
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| 25:11 | of the blood. What are the that would be involved in that? |
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| 25:16 | ? Liver? What if somebody has kidney in their own dialysis? It's |
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| 25:24 | huge issue, right? And they not even be able to do this |
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| 25:28 | . What if somebody has weak liver liver cirrhosis? Again, they would |
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| 25:33 | weighing their options, whether this is procedure that they can do. What |
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| 25:36 | that person is a child And you to make them lay down and lay |
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| 25:43 | still for 40 minutes beside that it's very difficult. So some people |
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| 25:49 | even have to get sedated to go this process. Yeah. How come |
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| 25:55 | cross the, not, not, does it cross the blood brain |
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| 26:03 | Well, I mean, it's, small enough and they're often designed so |
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| 26:07 | they easily cross the blood brain So you would use definitely an imaging |
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| 26:13 | you would use molecules to cross into brain. So uh they're usually typically |
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| 26:21 | , very small or they may have that facilitates uh lipid soil to cross |
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| 26:27 | blood brain barrier from the blood But typically it it's a systemic |
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| 26:34 | That means your whole body is That means it's penetrating everywhere. And |
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| 26:39 | scans are not limited to just the . People will do pet scans and |
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| 26:44 | scans. If they're looking for spinal issues, pinched nerve and they may |
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| 26:50 | MRI. But if they have cancer , suspected cancer growth, they may |
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| 26:56 | in clinical setting, a physician may you need an MRI, not necessarily |
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| 27:02 | MRI, but you need MRI and need pet scan. So they will |
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| 27:08 | to draw as much inflammation as In some instances, pet may show |
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| 27:13 | better that MRI. So inflammation may associated better with cancer's growth. The |
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| 27:21 | may not show that inflammation as the . So doctors again because this country |
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| 27:29 | so expensive with health insurance access, ? How much you can afford? |
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| 27:35 | primary is gonna say no, your is gonna say no to something you |
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| 27:40 | afford. So you have to weigh of these options. But a lot |
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| 27:43 | times you have a serious disease, condition, you will do multiple |
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| 27:47 | You will do pet scan, you do MRI C T or just to |
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| 27:53 | to resolve more detail, try to more because you really are. There's |
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| 27:58 | such thing as you walk into the office and rarely, it's like, |
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| 28:04 | , this is us, this is definitive diagnosis. This is it, |
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| 28:07 | just did some test results or something that. It's usually a quest and |
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| 28:13 | a person finds something they try to what, what it is more |
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| 28:19 | let's say, found the grows. you want to know it uh malignant |
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| 28:23 | is it be, you know, do you do to do that? |
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| 28:27 | know, you have to do your , you have to do scans, |
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| 28:29 | have to do this, you so it's, it's a combination of |
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| 28:32 | things. But so now you go the coil and you stay there for |
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| 28:37 | minutes, half an hour, imaging activity which is protons, electrons and |
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| 28:44 | radiation in the form of protons, gets picked up by these coils. |
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| 28:49 | in pet, you're looking at glucose . So a lot of times you're |
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| 28:54 | at the levels of two deoxy glucose and oxygenated glucose. In F |
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| 29:04 | you are looking at oxygenated or deoxygenated levels. So the difference is F |
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| 29:13 | . Both are functional pet and F . Both functional C T and x-rays |
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| 29:19 | not as regular MRI is not functional at revealing details in tissue. But |
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| 29:26 | MRI and pat are two functional techniques imaging brain activity. One is glucose |
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| 29:34 | . Another one is oxyhemoglobin, the , they are a lot more sophisticated |
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| 29:41 | spinoffs of these general imaging tools that mentioning here. There are tools by |
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| 29:49 | markers could be imaged with specific neurotransmitter could be imaged using these techniques. |
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| 29:55 | of them are already in practice others in sort of a clinical trial |
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| 30:03 | But now let's say you have a in either F MRI or a |
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| 30:09 | you tell them to look at an , let's say, or do something |
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| 30:16 | . But let's say you, you stimulate them, you give them |
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| 30:19 | sort of a stimulus and you see this part of the brain is activated |
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| 30:22 | the stimulus. So you image their as you're stimulating their brain. It |
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| 30:28 | matter what the stimulus is, you listen to music, you can think |
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| 30:31 | something you can have to solve a and then you do the same scan |
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| 30:36 | the same image where you tell the stop that task, whatever the task |
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| 30:40 | looking, listening, you know, just try to kind of be in |
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| 30:44 | moment. It's actually called a very , it's called sentinel state or |
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| 30:51 | In this case, it's control. is a very interesting term. It's |
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| 30:54 | soldier on duty, right? And soldier is on duty on guard is |
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| 31:00 | soldier actively emboldened doing something. they're on duty, they own guard |
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| 31:06 | they may be completely still and sitting , right? But they're still doing |
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| 31:10 | . So the brain even if it's doing something, even if it's still |
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| 31:14 | is still doing something. So in conditions, you still see these heat |
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| 31:20 | , these activity maps that are here red, those maps are different from |
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| 31:26 | . You can take the data during simulation data during the control imaging and |
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| 31:31 | the two. And this shows you difference that during this task during the |
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| 31:36 | task, this is what was different that this part of the brain was |
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| 31:40 | specifically during the stimulation patch. Now have a really nice what we call |
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| 31:45 | map of activity. OK. That you the map of where the neurons |
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| 31:51 | acting. Can you get to a cell level? No, the answer |
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| 31:58 | no, you cannot image a single using pet scan or am you cannot |
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| 32:05 | activity of a single neuron. You image activities from square cubed millimeters or |
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| 32:13 | centimeters. Those are the scales geo imaging. If you recall the average |
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| 32:21 | of a neuron is 10 micrometers 10 of the minus six Uh and |
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| 32:28 | Cube Millimeter, one millimeter is 1000 . So you could stack 100 cells |
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| 32:35 | to each other if it was Uh and then if you go in |
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| 32:39 | dimensions, 100 cells and 100 So you're talking about thousands of cells |
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| 32:49 | that are active, each one of will then represent a pixel. Because |
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| 32:55 | still imaging, you're still converting into visual image or digital display, which |
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| 33:00 | a a pixel. So in the , we can stab those cells and |
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| 33:10 | them and process them and record activity image dendritic spines and uncaged neurotransmitters in |
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| 33:17 | single spine level. And in the , it's not invasive because nobody's cutting |
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| 33:26 | it except injecting radioactive labeled materials is invasive for, for, for your |
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| 33:32 | in any case, not the actual , but it's, it's a toll |
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| 33:36 | your body. Let's put it this . So, uh how can we |
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| 33:41 | the 2? How can we get a single cell resolution to effuse cell |
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| 33:51 | in a clinical setting? We need call upon the unidentified flying, unidentified |
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| 34:00 | objects or we need to engage all you because I am hoping that one |
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| 34:09 | my students is gonna come up with really cool optical imaging method that can |
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| 34:17 | at a resolution of a single sound the way to these more generalized brain |
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| 34:24 | . So let's say this is not task, but this is a |
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| 34:30 | Let's say this is a pathological pathological activity. It's not a task |
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| 34:35 | looking or thinking pathological activity. What comes to mind when you see this |
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| 34:41 | here and this area may involve hundreds millions of cells. So, you |
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| 34:50 | , in the crowd, there's usually or two troublemakers, the start things |
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| 34:55 | then things go back from there, . Soccer. So, right. |
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| 35:03 | um OK, so what do you to know? I wanna know the |
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| 35:12 | troublemakers in the, in, in , in this hundreds of millions of |
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| 35:18 | , I wanna find the the two that are most active during a task |
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| 35:24 | during a pathology. In this I wanna know if these neurons express |
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| 35:30 | neurotransmitters like gab or glutamate or something . So, you know, in |
|
| 35:39 | there was x-ray crystallography and you had primary investigator, a postdoc and two |
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| 35:47 | students trapping a protein and a crystal using x-rays to expose a structure of |
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| 35:57 | protein. Five years of work for or five people. Now we have |
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| 36:04 | intelligence but based on all of this working that humans did, don't, |
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| 36:10 | get me wrong. It didn't just up with artificial intelligence can solve The |
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| 36:19 | in about 20 minutes or unknown new proteins based on all of this |
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| 36:26 | work by hundreds thousands of postdocs around world, graduate students, undergraduate students |
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| 36:33 | professors and trying to solve a different structure. So that was not possible |
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| 36:42 | 1990s, if you told somebody that you're doing here for five years may |
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| 36:46 | this machine 20 minutes. You you would probably stop doing it. |
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| 36:52 | except that it wasn't there. And you did 20 years ago, 30 |
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| 36:57 | ago contributed to that machine and that intelligence that now can solve that protein |
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| 37:02 | that that that reveal that protein structure 20 minutes. So there is |
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| 37:08 | there is hope, I I hope is hope in solving this in this |
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| 37:16 | that we could potentially get the resolution a single neuron, noninvasive in a |
|
| 37:21 | setting almost at the same level as do. In experimental neuroscience. And |
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| 37:27 | it will take artificial intelligence, maybe will take a lot of different technological |
|
| 37:32 | . But that would be amazing. could visualize a single cell from the |
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| 37:39 | that is non invasive and, and with the larger network issues or pathologies |
|
| 37:46 | functions and things like that. So here we end uh talking about |
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| 37:52 | C N S and we move in start talking about the visual system and |
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| 38:02 | have a series of lectures on the system. I believe we have three |
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| 38:07 | scheduled. If I'm not mistaken, may have uh a little bit behind |
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| 38:12 | the actual syllabus. We'll see where are before one. But introduction to |
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| 38:17 | visual system. Let's go to this . Now, this is a portion |
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| 38:25 | visual system that is coming in what a system, a system is not |
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| 38:31 | thing, a system is collection of parts of the brain and organs and |
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| 38:38 | that are involved in receiving the visual , processing the visual information, communicating |
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| 38:51 | visual information and tying that visual information we talked about to its own association |
|
| 38:56 | . Remember guys, we talk about secondary cur. So here you have |
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| 39:01 | uh V one and V two. is primary is V one, secondary |
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| 39:06 | V two. So in each V one is a pretty simple understanding |
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| 39:12 | the visual cortex of the outside And V two is more complex understanding |
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| 39:17 | V three, it's more complex And then after you had a visual |
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| 39:23 | with what you've stored in your you also associate the visual input with |
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| 39:31 | else with auditory olfactory somatic sensory, producing a motor output or an intellectual |
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| 39:42 | in your head that does not have motor output. So in the visual |
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| 39:49 | , information enters into the high, information gets processed into the retina in |
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| 39:55 | back of the eye, there are major pathways M N P that carry |
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| 40:01 | information outside of the retina in the of optic nerve, two cranial nerve |
|
| 40:08 | , after the fibers cross over, becomes optic track and optic track projects |
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| 40:12 | both sides. The left side, left side, right side, uh |
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| 40:16 | lateral genius of the thalamus and the the that information projects into G one |
|
| 40:27 | visual cortex. In the exhibit lobe , we have two major splits here |
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| 40:36 | the pathway that is going through your blow here, inferior temporal cortex called |
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| 40:46 | , inferior temporal cole. And that is concerned with color processing and it's |
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| 40:54 | with form and it's concerned this area with death. So this is the |
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| 41:01 | what this means. And this area is close to the auditory area. |
|
| 41:09 | sounds now that get processed in the area in the temporal lobe. As |
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| 41:15 | looking at the color, you may hearing some sound and you will associate |
|
| 41:19 | two through these pathways here. The pathway goes into posterior parietal cortex and |
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| 41:29 | dorsal parietal pathway. And it's concerned motion and death processing some form. |
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| 41:38 | motion, motion, this is moving . Uh so matter of sensory and |
|
| 41:45 | cortex is right because as something that perceiving is moving, it requires of |
|
| 41:53 | to do what potential it's a right? As you perceive a car |
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| 42:01 | is moving at you, your next is going to be I'm gonna get |
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| 42:05 | of the way the move. So now the motion perception is going to |
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| 42:12 | traveling to the to the area of brain and the primary motor cortex here |
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| 42:16 | other areas that will associate it according the reaction, the perception of that |
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| 42:21 | and then the reaction of that motion that's a visual system. And that's |
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| 42:26 | a portion of that visual system because at least 17 different areas that process |
|
| 42:32 | information. So we're just touching the of it. But by the time |
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| 42:37 | finish the visual system in this you will understand how at the level |
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| 42:41 | the primary visual cortex in V we actually form a perception what we |
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| 42:49 | a primal sketch or rudimentary sketch of information of the visual world that we |
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| 43:00 | . Yeah, so that's what a is. And so we have visual |
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| 43:05 | , we have auditory system, remember auditory system, we had pathways that |
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| 43:11 | went into thalamus. We mentioned the called M G N medial genu nucleus |
|
| 43:17 | we looked at thalamus. So it its own nuclei, it has its |
|
| 43:21 | pathways and auditory signal is gonna end in the auditory cortex in the temporal |
|
| 43:28 | . Oh So before we understand the of the information, we have to |
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| 43:34 | the anatomy and physical properties of But let's go back here and talk |
|
| 43:42 | these things a little bit. There's German term gestalt which is configuration reform |
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| 43:47 | it's a configuration reform as a So not just one thing, one |
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| 43:54 | but as a whole as it fits your visual perception. What we see |
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| 44:00 | properties of objects and the organization of by the brain. What we see |
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| 44:06 | the matter that we observed, we process information and 400 to 700 nanometer |
|
| 44:23 | . Does that mean nothing exists in infrared world? And ultraviolent world are |
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| 44:33 | that dwell in those frequencies and live them? What is, what is |
|
| 44:39 | world look like? Is a world of color? Does it look like |
|
| 44:46 | map? Does it look like a map? What is it? We |
|
| 44:53 | know because we don't perceive it. so I'm gonna share something really, |
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| 44:59 | cool with you that happened to me Sunday, I went to um intimate |
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| 45:08 | given by one of the probably most um meditation psychology Psychotherapy Psychiatry. A |
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| 45:29 | doctor by the name of Deepak He's written only about 90 books. |
|
| 45:38 | you don't know this man or anything his work. This is the man |
|
| 45:45 | is trying to advance the humanity in understanding of what we are as human |
|
| 45:52 | . How can we explain the world the 400-700 nm of wavelength that we |
|
| 45:58 | visually or other limitations that we perceive , which is 20 Hz to 20 |
|
| 46:07 | range. This is our range of on this planet. And what happened |
|
| 46:16 | he gave a lecture where he talked things that I'm gonna introduce to you |
|
| 46:21 | not gonna be on the test for next like five minutes or so of |
|
| 46:25 | spiel, I'm gonna be on on the test. But so Deepak |
|
| 46:33 | is very heavily involved in understanding human , human brain, human existence, |
|
| 46:43 | , human spirituality, evolution of human . OK. And I asked them |
|
| 46:53 | question that was related to what you about. You talked about a couple |
|
| 46:56 | things. Um So meta may have on metaverse. It turned into a |
|
| 47:06 | device, another gaming device. But Chopra talked about psychedelics and psychedelic |
|
| 47:15 | which is really interesting because psychedelic therapy anti addiction therapy. It's therapy to |
|
| 47:22 | with emotional distress with post traumatic stress , alcoholism, all of these |
|
| 47:29 | And it's right now actually in clinical for many different conditions and they're |
|
| 47:36 | they're turning out to be superior to reuptake inhibitors. So you guys know |
|
| 47:42 | that is. Serotonin re uptake Ok. So things like PROzac that |
|
| 47:48 | the presence of serotonin. All we talked about it when we talked |
|
| 47:53 | serotonin. So you have that and is a physical thing. Psychedelic is |
|
| 47:59 | a substance that you take in a fashion, under supervised protocols that are |
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| 48:04 | developed for psychedelic therapy, supervised by and people that know and understand different |
|
| 48:14 | substances such as slain, which comes mushrooms. And then he said, |
|
| 48:22 | know about this thing called metabolics and had their ears perked up. What |
|
| 48:29 | metabolic? So Trump said there, is a virtual reality world that influences |
|
| 48:39 | physical life. So there are studies if a person has a burn on |
|
| 48:46 | hand and they are overheating and they're in virtual reality, that's freezing, |
|
| 48:55 | body temperature goes down and the temperature around the wound also decreases. That's |
|
| 49:04 | that came from somebody's mind being exposed virtual reality. Didn't come from a |
|
| 49:13 | compra compress or, or cold press claim ha it came from somebody thinking |
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| 49:20 | they're in a cold environment, in thinking those thoughts affected their physical |
|
| 49:30 | And we do that, we have power of the mind to do |
|
| 49:35 | So there were three questions that were Uh deep chakra. They gave the |
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| 49:42 | question to me and I was sitting him maybe like if you're sitting for |
|
| 49:47 | like 10 ft. And so I really interested in what he thinks will |
|
| 49:52 | the next evolution of the human Where are we going and what is |
|
| 50:00 | to help us accomplish to evolve and the next next stage? What is |
|
| 50:07 | next stage? What is the next for those humans and brain anatomy is |
|
| 50:12 | the camp is gonna become a six structure, life structure for Neocortex? |
|
| 50:17 | go. How's that going to Are we gonna be able to perceive |
|
| 50:23 | nanometers we're gonna be able to see ultraviolet, right? How's that |
|
| 50:30 | So I asked him that question, next and how that is going to |
|
| 50:34 | ? And I was thinking about it , in the terms of brain plasticity |
|
| 50:39 | human evolution of hope for what we to kind of make it better and |
|
| 50:45 | it better. And he proceeded to me a lecture for about 10 |
|
| 50:50 | which was amazing when a master guru to you for 10 minutes, eye |
|
| 50:55 | eye. And his main point was for humans to evolve our brains and |
|
| 51:05 | spiritual existence, moral existence, we to forget about matter. And the |
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| 51:16 | why we have to forget about matter the way we understand matter is because |
|
| 51:23 | only seen matter within this range. whenever we discover some technological tool, |
|
| 51:32 | we see something that animals see uh changes our understanding and changes our perceptions |
|
| 51:43 | there and he believes with forgetting the um metabolics and brain plasticity, maybe |
|
| 51:55 | next sort of a stage of the evolution and the, and the human |
|
| 52:00 | in the, in the human OK. So we will not ask |
|
| 52:05 | any questions on that, but please up deepak chopra, look up a |
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| 52:12 | video, like I said as a York Times best selling author, time |
|
| 52:16 | time over and over again, very successful entrepreneur too and just a |
|
| 52:22 | inspiring person. So have you heard tell you to forget matter before? |
|
| 52:31 | , me neither. But uh but you think about metabolics and the power |
|
| 52:37 | the mind, how that overcomes the overcomes the physical being that becomes AAA |
|
| 52:44 | interesting thought to, to care and with you and know our limitations as |
|
| 52:50 | beings. So huge world, infinite number of universes out there. |
|
| 53:03 | probably 100 20 chances in the 100 other forms of life with different perceptions |
|
| 53:10 | things like that. So what we represents properties of objects which is 400 |
|
| 53:15 | 700 nanometers and organization of sensations by brain because the brain is organized in |
|
| 53:21 | structures and certain connectivity. So what see is what we get Uh three |
|
| 53:32 | experiences are formed From two dimensional objects variations of these objects. So we |
|
| 53:41 | the ability to take, oh Oh man, I have to use |
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| 53:50 | uh water or alcohol. Maybe I'll so. Oh, I'll have to |
|
| 54:00 | a little, little bit. Zoom guys. There we go. |
|
| 54:09 | if I do something like from this uh this is two dimensions, |
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| 54:14 | Two dimensions. Why is it Dimension? Because it's dot on the |
|
| 54:22 | . So three dimensions. What does see here? Oh, thank |
|
| 54:40 | Thank you. It's just blank the just do that much. Why do |
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| 54:47 | think it's a, you associate it something that you saw was a |
|
| 54:52 | a box you open, you were little child, you open the box |
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| 54:55 | a cube that you learn that you it. So you think it's a |
|
| 54:59 | ? Now, when you see it the board, it's flattened, there's |
|
| 55:03 | really that much to do this. you still think it's a cute. |
|
| 55:08 | . So we do these things right our, in our heads and it's |
|
| 55:12 | stable, it's pretty stable. Most you just said it's a cute, |
|
| 55:16 | know, because you didn't say this Lines and four dots connected by 16 |
|
| 55:22 | lines. and uh so this is a stable pattern, more or less |
|
| 55:29 | constant. Despite variation, we'll look some of these variations. The brain |
|
| 55:33 | certain assumptions about what is to be in the world expectations that seem to |
|
| 55:37 | them apart from experience. You've learned a cube open. This is what |
|
| 55:41 | looks like two dimensions, looks like cube and from built-in neural wiring for |
|
| 55:47 | vision, right? So there's these and wiring the vision. So this |
|
| 55:57 | on top, if I ask is there any pattern to this on |
|
| 56:01 | here? Again, you say it's square, square number of dots and |
|
| 56:05 | square pattern. If I ask what do you see here on the |
|
| 56:11 | ? You will say while I'm seeing columns here, blue and yellow, |
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| 56:15 | and yellow, what about here? will say while I'm seeing these rows |
|
| 56:19 | , yellow and blue, yellow and , yellow and blue and that is |
|
| 56:23 | similarity principles. So we group things are simulate together and we say that |
|
| 56:28 | they're yellow, they must be in column, they must be in one |
|
| 56:32 | . But what if I told you not the case? Actually, it's |
|
| 56:35 | a line that consists of blue, , blue, yellow, blue, |
|
| 56:42 | . Maybe that's my intent, but grouped it together based on that singularity |
|
| 56:48 | and then proximity principle. So you move the objects closer together in this |
|
| 56:57 | or you can move them closer together versus vertically. And the same thing |
|
| 57:03 | , these looks like columns and these like rows. And again, maybe |
|
| 57:08 | intent was that this is a column , you know, more separation and |
|
| 57:14 | group together to another column. It's a road. So I would have |
|
| 57:19 | explain that to you. But we certain assumptions just by looking at |
|
| 57:23 | this is a row, this is column, this is all yellow |
|
| 57:27 | this is all blue and it's close . So they have to be somehow |
|
| 57:32 | , they're matching. There's a lot illusions in the, in the outside |
|
| 57:42 | . I don't know what I can but I use this have to go |
|
| 57:47 | . Yeah. So this is uh know, a really famous delusion. |
|
| 57:53 | look, what I'm gonna do is gonna put a marking here, a |
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| 58:00 | here on this side, a marking . OK. And then I'm gonna |
|
| 58:05 | a straight line through it. So amount marking here, we draw a |
|
| 58:20 | line through it. So it's the distance apart, right? Everybody see |
|
| 58:25 | , It's the same distance apart, two things and they were to say |
|
| 58:37 | . And if I were to ask which er which, which line is |
|
| 58:41 | the one on top or the one the bottom, you also say they |
|
| 58:45 | the same, but then I did like this and then I'll ask you |
|
| 59:01 | same question. Which line do you is longer? Um Most of |
|
| 59:06 | if you didn't see me do what just did with this, you would |
|
| 59:12 | the the bottom line is. So is, there are illusions how other |
|
| 59:18 | , how other lines of object make perceive things bigger colors make you perceive |
|
| 59:24 | , bigger, right? Like when fashion time and stuff like that, |
|
| 59:28 | know, don't wear white is gonna you big black, you know, |
|
| 59:32 | like that, but it's all of perceptions, right? So it's also |
|
| 59:38 | with other objects. It's pretty The person sitting further away. You |
|
| 59:42 | in the hall and you see two sitting, you don't assume that the |
|
| 59:46 | further away is only half the size this person and they're sitting on a |
|
| 59:50 | that's half the size of this chair even yet, maybe they're just |
|
| 59:55 | a small midget that's sitting in the back of the corridor there on the |
|
| 60:00 | little chair, you know, so adjust for these things, you |
|
| 60:03 | and when you come up closer to door, you don't think that that |
|
| 60:07 | , which looks really tiny door over . I wonder like it's John M |
|
| 60:10 | your door. I wonder if I fit in that bar or into |
|
| 60:14 | You assume that while I'm just gonna up and the door is gonna become |
|
| 60:18 | size, I gonna walk in. adjust for all of these things, |
|
| 60:21 | depth perception, your size perception, learned and it's ingrained. This is |
|
| 60:27 | classical again, illusion of two faces vase. This is green frog, |
|
| 60:33 | fish. The other thing is once see an optical illusion, you can |
|
| 60:38 | that these are very simple, they're complex optical illusions. There are three |
|
| 60:43 | optical illusions or optical illusions from two that create three dimensions. But in |
|
| 60:49 | very complex way with movement and with movement in the tune, they're all |
|
| 60:56 | there are some that are online. believe so too. These are simple |
|
| 61:00 | , but this is what our limitation . And we talk about properties of |
|
| 61:05 | , its wavelength, it has certain and the wavelength obviously is in certain |
|
| 61:11 | . So 400 nanometers to 700 red, orange, yellow, |
|
| 61:20 | hello indigo Violent Roy GB red, , yellow, green, blue |
|
| 61:35 | violent you have infrared. You have amplitude is how bright or how strong |
|
| 61:44 | light is. You go shop for flashlight if you're going camping or fishing |
|
| 61:48 | something like that, I tell you has 300 lumens and this has 600 |
|
| 61:54 | . What does that mean? It that just the stronger light but it |
|
| 61:58 | be within the same frequency with the white light or if you're buying |
|
| 62:02 | flash light red, it's gonna be brighter, right? Doesn't mean the |
|
| 62:07 | of view has changed or the So the light has property so that |
|
| 62:13 | can reflect, it can get absorbed get refracted and once it enters, |
|
| 62:21 | gets refracted from air. This is , this is the pupil and the |
|
| 62:27 | surrounding it where the inflammation comes in . This is the extraocular muscles controlled |
|
| 62:34 | ocular motor nerve. This is a of the whole visual system. And |
|
| 62:40 | is the anatomy of the eye. have the lens here that is supported |
|
| 62:45 | the cellular bodies. It's a sensory . So the lens can become thicker |
|
| 62:51 | it can become thinner by becoming thicker thinner. It can focus the image |
|
| 62:57 | on the back of the eyeball, the retina. You have the humor |
|
| 63:03 | in the front and the virus humor the eyeball that's shaped or little she |
|
| 63:09 | substance almost. And the back of eyeball will contain retina here. |
|
| 63:16 | But we'll get into some of the of that directly in the path of |
|
| 63:22 | uh pupil. As the light it is being directed to a very |
|
| 63:27 | area called the where the optic nerve out. You have a blind |
|
| 63:34 | These are the optic nerve crab nerve too that are coming from retina that |
|
| 63:40 | retinal ganglion cell fibers. So there three major subtypes of cells. There |
|
| 63:47 | photoreceptors, bipolar cells and retinal gang . The photoreceptors are going to transduce |
|
| 63:54 | convert information of light into an electrochemical . There's going to be processing in |
|
| 64:01 | retinal circuit here and there's going to an output of activity from retinal gang |
|
| 64:08 | into the thalamus and into the And in the, as you can |
|
| 64:13 | , there is a special indentation in structure here that allows for the light |
|
| 64:18 | be concentrated as much as possible in central area of the retina. This |
|
| 64:24 | where we have the highest spatial This is when you read the smallest |
|
| 64:29 | or try to look as far as and discern them with the highest |
|
| 64:34 | It's called OK, highest acuity And we constantly move eyes and refocus |
|
| 64:41 | this area. If we are really into discerning detail. Now, when |
|
| 64:46 | look at something, you can see or something in a really great detail |
|
| 64:51 | you can still see the surroundings, they're not in this great of a |
|
| 64:54 | . And if you want to see , you're gonna have to move your |
|
| 64:57 | to see more detail in other surroundings individuals. So the information, the |
|
| 65:03 | of the information, the direction of light actually coming through the eyeball will |
|
| 65:09 | to pass what are called the jungle fibers and circuits here to get into |
|
| 65:16 | photo receptors that are located in the back of the retina. And then |
|
| 65:21 | processing will take place initially in the bipolar cell system. Finally, in |
|
| 65:28 | retinal gang and cells that are gonna the major output of the retina. |
|
| 65:34 | . So the direction of the light way and signal processing, electric chemical |
|
| 65:42 | synoptic transmission is in the opposite We have two types of photoreceptors cone |
|
| 65:49 | rod rods are in one subtype They are achromatic cones are blue green |
|
| 65:59 | red. OK. So the three of cone filter receptors. And as |
|
| 66:05 | mentioned already, if you're looking at object far away, you're focusing on |
|
| 66:11 | object, far away, that object move. And as that object moves |
|
| 66:16 | to you, you still wanna have keep that object in focus. And |
|
| 66:21 | do that, you're gonna adjust the of the lens to keep that object |
|
| 66:26 | in focus. Always on the back the retina, uh eyeball on the |
|
| 66:31 | , the back of the retina to photoreceptors. So this is normal |
|
| 66:36 | If you have tropia, that means your lungs can adjust steadily to far |
|
| 66:43 | near objects. So you can perceive . And if you cannot adjust, |
|
| 66:49 | may need a correction. Yeah. that adjusts for you to put things |
|
| 66:55 | focus that otherwise are out of So typically we do that with the |
|
| 67:02 | ligaments and relaxing, contracting those ligaments changing the shape or the thickness off |
|
| 67:10 | lungs. But if you have the lens is now capable of adjusting |
|
| 67:19 | and things are blurred, they're being behind the space that would fall immediately |
|
| 67:26 | the retina. So you would use convex lens or glasses to adjust to |
|
| 67:36 | the image for hyperopia. For that image is some distance it's focused |
|
| 67:47 | before the retina. Again, out focus blurry can discern detail. So |
|
| 67:54 | have concave ones that will adjust and now allow for that image to be |
|
| 68:03 | on the run and uh So this and lenses and uh Lasi can with |
|
| 68:14 | laser, adjust the lenses and uh certain uh areas to, to basically |
|
| 68:24 | the shape of those lenses so that can focus better when we look with |
|
| 68:31 | eye. So if you close your eye, right eye, We have |
|
| 68:37 | around us, but one eye is to be able to see a 150 |
|
| 68:42 | . We call it the uh degrees visual angle, 150 from one on |
|
| 68:53 | you hold like an object really close that one eye. It may occupy |
|
| 69:01 | all of it like 100 degrees of of your vision. And put aside |
|
| 69:06 | example, typically when the moon is risen, we know the distance to |
|
| 69:12 | moon that dot that you see when risen, it's about half a degree |
|
| 69:19 | visual angle out of this 150. that dot that right dot That moon |
|
| 69:27 | be perceived by about 100 40 micrometers space on the retina. So that |
|
| 69:33 | bright dot is perceived by 100 and micrometers of space in the retina, |
|
| 69:37 | means a whole bunch of photoreceptors will activated in this space of the retina |
|
| 69:42 | that point to be seen. What the Jupiter when the Venus were |
|
| 69:48 | And the Jupiter would have its own ? And if it was closer, |
|
| 69:52 | it would occupy 100 and 60 micrometers space. If the unus is even |
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| 69:56 | here, occupy maybe 300 micrometers of , you know, perceiving that |
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| 70:03 | So here is occupying almost all of records here when it's so close |
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| 70:10 | Cool. Now, the two important is I think that I uh overs |
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| 70:17 | a little bit too much but too point here is that we have photoreceptors |
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| 70:25 | they're the only light sensitive cells that that they're the only ones that are |
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| 70:31 | to react to light. And then have ganglion cells, it's the only |
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| 70:35 | that comes out of the retina. , photoreceptors or bipolar cells, you |
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| 70:39 | put anything out. Uh optic nerve nerve two is a collection of retinal |
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| 70:46 | and cell aides. So for the of evolution of the human brain and |
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| 70:54 | , I'm gonna end this lecture here . Uh Look up Deo chakra and |
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| 70:59 | finish up the retina and the photoreceptors in about 15 minutes when we come |
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| 71:06 | on Wednesday before we move to more on digital systems. Thank you very |
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| 71:12 | |
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