| 00:02 | Today is the lecture 15 of It's October 20 and we have been |
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| 00:11 | the structure and function of major parts the south, some of the anatomical |
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| 00:18 | the meninges, the vascular I'm sorry ventricular system. We moved into looking |
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| 00:28 | the development, early development, no . And then a couple of conditions |
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| 00:35 | with neural tube formation that are abnormal that can form. We looked at |
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| 00:41 | differentiation of the primary vesicles into secondary further differentiation into a complex structure of |
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| 00:51 | brain. And we left off, talked about the cortex how it is |
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| 00:58 | six layer structure, how it's a structure and also colonist structure at the |
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| 01:03 | time talked about primary secondary hierarchical processing sensor information and then the association |
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| 01:12 | the overall structure of the brain. discussed different parts of the spinal |
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| 01:20 | different parts of the brain stem, cephalon, thalamus, hypothalamus. The |
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| 01:25 | nuclei such as basil ganglia, hippocampus the amygdala and cerebral cortex, cerebral |
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| 01:33 | and the major lobes. We ended talking about the thalamus and thalamus is |
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| 01:42 | structure where all of the sensor information it reaches cortex. So let say |
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| 01:49 | information. Coming into the air center cochlear to before it goes into the |
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| 01:54 | the auditory cortex it will actually be through multiple stations. But the last |
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| 02:01 | before it goes into the cortex is and what we saw is that thomas |
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| 02:07 | comprised of multiple nucleons. So each will observe a different function. The |
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| 02:14 | inputs, the visual inputs that will studying today from the retina will leave |
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| 02:20 | it will enter the specific nucleus of thalamus called lateral nucleus and from there |
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| 02:27 | will go into the primary visual cortex the occipital lobe area, 17 auditory |
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| 02:34 | will enter into the medial nucleus before goes into the auditory cortex and the |
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| 02:40 | lobe. It's a matter of sensor , everything from the neck down that's |
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| 02:47 | through the spine through the spine, will ascend through the spinal cord, |
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| 02:54 | column, n dorsal column nuclei and go into the ventral ministerial lateral |
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| 03:02 | The and then projecting to the primary cortex and uh in the new |
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| 03:12 | So at first it was thought that is a relay station. You know |
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| 03:17 | the retina into thalamus and then into over here for visual inputs. But |
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| 03:24 | know that there are sophisticated circuits, and inhibitory circuits within these individual nuclei |
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| 03:32 | they are capable of adjusting or what call modulating or gaining, allowing more |
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| 03:40 | a sensory signal to come in or of the sensor signal to commence. |
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| 03:44 | they actively essentially influence the sensor signal it reaches the cortex. The cortex |
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| 03:51 | also going to communicate back into the nuclei and we'll see how that works |
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| 03:58 | we study the I think the third of the visual system. The other |
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| 04:05 | feature of the thalamus is that surrounding thalamus you have this sheet that we |
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| 04:13 | to as a particular nucleus and it have down below the entire thalamus And |
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| 04:19 | is a collection of the inhibitory inter that will also be controlling activity, |
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| 04:25 | activity and processing of that activity at level of the thalamus. Hypothalamus is |
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| 04:32 | of the autonomic control involved in involuntary function control. We talked about hypothalamus |
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| 04:41 | involved in neuro endocrine system. We about hypothalamus being involved in H. |
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| 04:46 | . A hypothalamic pituitary adrenal axis for response and control of stress hormone. |
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| 04:54 | also has multiple functions in the It has rather lose blood brain barrier |
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| 05:02 | it can detect changes in temperature. can also detect any toxins that may |
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| 05:08 | found in the blood and reacted before structures do. Uh And finally a |
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| 05:15 | of down in south Carolina is a cosmetic nucleus which is the master body |
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| 05:19 | regulator. It's the nucleus that expresses transcription factors during the day or during |
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| 05:26 | evening. And an icon and that your awakened sleep cycles or circadian eternal |
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| 05:35 | . So here are some structures that discussed And this exam is gonna be |
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| 05:40 | rich in questions for labeling different structures different functions of those structures in the |
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| 05:49 | . This is our optic eye ASM the optic nerves will cross over here |
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| 05:55 | eye ASM you have the corpus this massive fiber bundle that will interconnect |
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| 06:01 | two hemispheres have this big what is Singulair drivers here. The cerebellum from |
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| 06:08 | back of the brain. You have nucleus that we talked about and there |
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| 06:14 | have the hippocampus also in three dimensions in the brain. So these are |
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| 06:19 | good labeling questions. Uh cerebellum, has its own to left and right |
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| 06:27 | in the middle of has a verma's like we talked about cerebellum, cerebellum |
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| 06:33 | involved in procedural memory, is involved the iptc lateral control of motor |
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| 06:40 | It's involved in fine tuning and adjustment motor commands that have already been initiated |
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| 06:46 | the cortex before it reaches the spinal for the final execution of most of |
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| 06:52 | motor commands that happen below the So this structure is responsible for procedural |
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| 07:00 | . This structure and the campus is for semantic memory we discussed. The |
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| 07:06 | is also responsible for spatial memory or memory and in alzheimer's disease of the |
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| 07:14 | is one of the structures that gets by Alzheimer's disease and one of the |
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| 07:19 | of alzheimer's is inability to orient yourself space, not just in time but |
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| 07:25 | in space. So hippocampus is also for spatial memories that we create um |
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| 07:33 | are often associated because you typically associate in new environments with something else that |
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| 07:39 | can recognize, some signs that you , some store name that you recognize |
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| 07:43 | such. So now this is procedural which is mechanical, more of a |
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| 07:51 | motor tasks riding a bicycle but it be as complex as doing somersaults with |
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| 07:59 | skateboard, you know 5m up in and such. If you remove the |
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| 08:07 | , the cerebellum would be exposing the peed uncles. So this is where |
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| 08:13 | is attached uncles. And obviously because is cerebellum, you're looking from the |
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| 08:20 | side. So you're looking at you can see the fourth ventricle part |
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| 08:27 | the ventricular system narrowing into go into spinal canal and the spinal cord. |
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| 08:35 | if you remove the cerebellum you expose of my favorite structures that we talk |
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| 08:41 | corporate quadra gemini. It is composed the two left and right, superior |
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| 08:46 | , sauce and two left and right calculus. So superior caligula sees, |
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| 08:51 | will learn as we study. The system is responsible for psychotic or very |
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| 08:58 | uh jump like eye movements and empirical is involved in processing auditory information. |
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| 09:08 | vision, certain part of the digital and auditory information. Now, everything |
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| 09:18 | we do that we sense from below the neck down comes from the spinal |
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| 09:28 | that communicate that information to the spinal . And we will actually look at |
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| 09:33 | spinal nerves that are shown here and them in a minute. But we |
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| 09:38 | finished talking about major parts of the and now we're gonna talk about brain |
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| 09:44 | and what are some of the nerves come out of the brain stem. |
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| 09:48 | everything touch sensation, heat, pain here down from basically below the skull |
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| 09:57 | processed through spinal nerves that enter into neck, into the cervical air, |
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| 10:02 | and all the way processing information from lower body. Now, everything that |
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| 10:07 | feel on your face, everything that move in your face, like your |
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| 10:14 | , you speak and wink turn control of the eyes off the face of |
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| 10:25 | head. This is the cranial nerves these cranial nerves are distributed throughout the |
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| 10:32 | stone there are 12 cranial nerves and start from the top, more |
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| 10:39 | going down to inferior from 1 to . The first nerve is the olfactory |
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| 10:48 | and it's not shown here. And is shown here for example is this |
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| 10:54 | the back. Okay, so this dorsal. So you can see the |
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| 10:58 | curriculums here for example And the second nerve is shown is the optic |
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| 11:04 | So there are 12 nerves. But gonna want you to know six out |
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| 11:09 | those 12 nerves and I will tell which ones they are optic nerve as |
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| 11:13 | can see obviously is one optic nerve comes from one I this is the |
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| 11:18 | view and from the other eye. then the optic nerves cross over through |
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| 11:23 | optic chasm and after they cross over optic chasm, then they become optic |
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| 11:30 | optic tract will contain components of both left and the right eye. This |
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| 11:36 | number two, Number three is ocular and all three of these nerves that |
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| 11:43 | you to know 1234. Factory smell information optic nerve visual system because we |
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| 11:51 | study that in greater detail. Ocular . I want you to know that |
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| 11:56 | it's a part of what we're going discuss with the movement of the eyeball |
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| 11:59 | the visual system. But also as can see, some of the cranial |
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| 12:04 | will tell you what they do. ocular the eye motor motor for the |
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| 12:12 | movement of the eye. Other nerves tell you what they do. So |
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| 12:17 | a nerve is number four. We discuss that in great detail. Trigeminal |
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| 12:22 | wants you to know number five. doesn't tell you what it does but |
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| 12:26 | tells you something about the nerve. germinal has three major branches for that |
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| 12:33 | . Five. And I want you know it because it's the largest |
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| 12:38 | You should be able to recognize. fall somewhere in the middle of the |
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| 12:42 | nerves. And you can see that will have 1234. Then you have |
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| 12:49 | the ponds you'll have this very prominent . You should be able to label |
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| 12:54 | trigeminal nerve and trigeminal nerve is responsible a lot of sensory and motor functions |
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| 13:00 | the in the in the face and facial muscles. Then you have a |
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| 13:07 | nerve then which is six. You facial and intermediate nerve which is |
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| 13:15 | You have vestibular cochlear nerve which is . And I want you to know |
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| 13:21 | nerve so so far. 12358. tubular cochlear to it's also one of |
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| 13:27 | mirrors that tells you what it This tabula apparatus cochlear cochlear so it |
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| 13:34 | to uh fiber bundles one from the or province, one from the processing |
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| 13:41 | from the copa. Okay, so so good. Mr. Number |
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| 13:47 | Glass. A forensic real and vagus . So Glass of forensic real and |
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| 13:55 | nerve nine and 10. Glass. Perenchio Lhasa is tongue for ngos |
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| 14:03 | So something to do with control or information, remote information from the town |
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| 14:09 | bearings. Something to do with um with with with with other different complex |
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| 14:19 | moving of the tongue. So happened nerve which is number 12. And |
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| 14:25 | don't mean to skip over accessory nerve is a lot of about half a |
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| 14:29 | cell again. Has to do something tongue and underneath the tongue movement or |
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| 14:35 | of the uh sublingual regions essential. . So what nerves I want you |
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| 14:42 | know is 1,235, eight and It is supposed to be like oh |
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| 14:54 | and 10 is the vagus nerve because know the vagus nerve uh in the |
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| 15:00 | that you know that that's where the transmission was discovered that vagus nerve innovates |
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| 15:08 | heart. But vagus nerve is one the most extensively um innovating nerves throughout |
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| 15:16 | body and the viscera pop, It's to remember all of the 12 cranial |
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| 15:22 | and I'm not asking you to remember all. I'm asking you to remember |
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| 15:26 | of them Now. Some of these and sensory, some of them are |
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| 15:32 | . Some of them are both, they're both have sensory component and motor |
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| 15:38 | . When I take them to graduate , the head and neck, we |
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| 15:42 | to know all 12 all of their and we have to be able to |
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| 15:47 | them on the real human cadaver. that was really uh interesting and uh |
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| 15:56 | had an opportunity as undergraduate to actually the surgeries for the tests and expose |
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| 16:01 | nerves. Put little like red tags yellow tags and green tags with numbers |
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| 16:08 | we have students and later me as mentor, we would basically have them |
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| 16:13 | correctly for the functions and for what are. So when we had to |
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| 16:17 | it, we came up with this . This pneumonic is not, it's |
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| 16:25 | great. It's not perfect. But something that worked for me for a |
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| 16:29 | long time. And this is the bunny pneumonic and why we came up |
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| 16:36 | this is because we were bored. was late at night and we had |
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| 16:38 | prepare for the exam and no other that were in the text books or |
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| 16:43 | . We're sticking. So we started around came up with bugs bunny |
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| 16:49 | oh to touch and feel very green . Ah so here, the |
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| 16:58 | the first letter of the word 002 . Touch T corresponds to the first |
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| 17:09 | of the cranial room. So, , back throughout the optic optimal |
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| 17:15 | two stroke clear, four trigeminal five since six facial 7. Very |
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| 17:25 | nine federal vegetables, Davis, And uh that really helped us memorize |
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| 17:34 | of the nerves and and and their . Uh and I never forgot |
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| 17:38 | no money. So when we needed kind of figure out which one's a |
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| 17:46 | , which one's the motor. Then Bunny said, so, so much |
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| 17:52 | . But my brother says, Bugs makes more. So here s is |
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| 18:01 | m his motor and B is both motor. So, so, so |
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| 18:07 | money. But if you remember you remember that the first three nerves |
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| 18:11 | I'm asking you to know. so much money. But so sensory |
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| 18:18 | , motor and both components sensory and number eight sensory. This video copia |
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| 18:26 | 10 vagus nerve is both okay, and motor. So you can use |
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| 18:33 | pneumonic, you don't have to, can come up with a separate pneumonic |
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| 18:37 | just the six nerves that I'm asking to know for this exam. And |
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| 18:43 | what do you need to know about nerves? So you need to know |
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| 18:46 | one is which you need to The trigeminal is the largest, you |
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| 18:51 | probably be able to label the trigeminal and the optic nerves and the chi |
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| 18:56 | um pretty well because they just stand so well uh you should probably know |
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| 19:02 | vagus nerve is where the neural transmission discovered. So I may ask you |
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| 19:08 | this point. The question related to fellow, his discovery could be which |
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| 19:16 | nerve below we stimulate number 46789 And so if you study that and |
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| 19:24 | studied the first portion of the course you have the answer very easily. |
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| 19:30 | ? Uh So hopefully this helps you and I hope it does because if |
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| 19:36 | go on into the professional world and anything to do with like biological medical |
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| 19:43 | it's very often that you may have come back to maybe you're working in |
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| 19:48 | , rehabilitation, Davis nerve stimulation for . Uh You're in dental school taking |
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| 19:55 | neuroscience, you're in medical school taking neuroscience. You're in the school of |
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| 20:02 | studying the structure of the retina. all of these things become very useful |
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| 20:09 | hopefully it will help you in the as well. So let's go back |
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| 20:17 | not this. But this this is we were this is what's going on |
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| 20:23 | this is the sensations from the face had an act the control the chewing |
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| 20:29 | movement of the tongue, the output the speech final output of the speech |
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| 20:35 | out controlled by the cranial nerves. the spinal nerves are associated with their |
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| 20:44 | vertebra. So you have seven cervical , C. One through C. |
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| 20:50 | . And you have the first cervical above. And then you have the |
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| 20:56 | cervical nerves. So you have a of eight cervical nerves associated with the |
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| 21:01 | vertebra. Then you have thoracic One, choose thoracic 12, vertebra |
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| 21:06 | . 12. And you have 12 nerves. Then lumber L. One |
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| 21:12 | L. Five, lumbar vertebra And you have five lumber nerves and |
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| 21:17 | you finally have the sacral vertebra and cervical nerves shown there now. Uh |
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| 21:27 | you can see the nerves radiate out between each vertebra on each side and |
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| 21:33 | one of the spinal nerves on each will be comprised of the sensory and |
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| 21:37 | component. And we'll look into the of that. And quite often you |
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| 21:43 | hear in the clinical world the injuries C. Three or C. Four |
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| 21:49 | the nerve is pinched. Let's say T. One. And if the |
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| 21:55 | pinch to ti wan then very likely pain would be associated with the area |
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| 22:02 | the nerve from. T wan right thoracic burning for juan projects toward the |
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| 22:08 | area and and the arm. So there's numbness for example or something like |
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| 22:15 | and that's because of the pinched nerve this region because of the pinch spinal |
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| 22:21 | , it's very likely that it's going be T. One or C. |
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| 22:24 | for example, I'm sorry, or . Eight. Okay, so each |
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| 22:30 | will process information from different parts, the way from the head to the |
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| 22:37 | extremities, spinal cord proper ends at L two L three. And about |
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| 22:44 | area here, number two, Number . And from that point on it |
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| 22:50 | out into this uh kind of a out fiber bundle that's reminiscent of horse's |
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| 22:58 | . And therefore it has the name , the queen of kata, kata |
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| 23:04 | , retail china, equestrian horses So this is the spinal nerves and |
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| 23:12 | innovation that you will see. So all of the sensors and motor |
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| 23:17 | Of course, motor commands will initiate the cortex. Right? And basal |
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| 23:23 | . The final execution of these commands the neck will be through this movement |
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| 23:29 | the activation of the spinal cord. nerves. Yeah. No, not |
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| 23:37 | . Because we'll come back to when talk about the Samata sensor system. |
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| 23:42 | I was actually thinking about that yesterday like why aren't the to kind of |
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| 23:46 | together the two images? And I'm to redo the slides for the accessibility |
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| 23:51 | . They changed all of the rules us. I think almost overnight. |
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| 23:56 | I'm gonna potentially think about including But that's a good question that each |
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| 24:01 | of those nerves will also be associated a different area of the skin where |
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| 24:06 | sensor information is that is processing to come back and talk about it. |
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| 24:13 | Five. So so each spinal I said as a sensory component dorsal |
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| 24:23 | ganglion. So these are the peripheral . The bundle here ganglion is the |
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| 24:30 | of the DRG cells that the central and the central axons will innovate in |
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| 24:37 | dorsal side here and then the motor will the difference right? The output |
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| 24:46 | the motor neurons will exit out through ventral side, also called the ventral |
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| 24:51 | . And see. So these are motor neuron fibers that will form and |
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| 24:56 | enveloped, Kind of the same spinal running into a different part of the |
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| 25:03 | . You can see that this gray here let's label dorsal horn ventral |
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| 25:10 | spinal canal is where the super spinal is. And so if you want |
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| 25:16 | , for example, do a spinal uh which is basically sampling the cerebral |
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| 25:25 | fluid. And that happens if somebody meningitis and there's an infection in the |
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| 25:31 | , bacterial or viral infection on the . There's going to be infectious agents |
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| 25:40 | the cerebrospinal fluid about the bacteria viruses . And you cannot really immediately put |
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| 25:47 | needle into the ventricle because that's a complex neurosurgical procedure. But what you |
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| 25:57 | do is you can sample through the fluid is called the spinal tab. |
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| 26:02 | you would you would basically tap through meninges which surrounds the spinal cord |
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| 26:09 | But you would do it in the where the spinal cord proper already has |
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| 26:15 | . So right below that L. . You would put attractants sort of |
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| 26:20 | so soft needle and draw out some the cerebrospinal fluid which is much easier |
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| 26:28 | to do it in the lumber And it's not really a as complicated |
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| 26:34 | putting a needle into somebody's ventricles through parts of the brain and statue. |
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| 26:42 | that's just some valuable information. Obviously meninges meninges are gonna be protecting the |
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| 26:47 | cord that where there are so much in the spinal cord you see the |
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| 26:53 | area. So it looks sort of a butterfly with a dorsal horn and |
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| 26:57 | ventral horn. And this is where so mazar mostly off the uh into |
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| 27:04 | of the spinal cord and the motor of the spinal cord. Because the |
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| 27:07 | root ganglion so mazar here in the in the ganglion. Okay and in |
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| 27:15 | back you can see what are labeled dorsal columns. So there is surrounding |
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| 27:21 | gray matter. We have the wide the wide matter that several projections that |
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| 27:27 | either ascending from the major sending projections going through the dorsal columns or |
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| 27:33 | So that's information from the spinal cord is being communicated to the brain and |
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| 27:40 | brain also communicating information back to the cord. These are the major sensing |
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| 27:49 | sensory pathways to the dorsal column. I want you to know this and |
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| 27:54 | able to recognize dorsal column is the sending sensory path Alex. And in |
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| 28:01 | to dorsal column he also has finally track some of these tracks or interconnections |
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| 28:10 | you where they originate and where they're to. So if it is spinal |
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| 28:18 | IQ, that means it originates and that goes into these columns, that |
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| 28:24 | it's ascending tract, vice versa. can have Corta co spinal tract which |
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| 28:33 | from originating in the cortex and going spine. Is that ascending and |
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| 28:39 | Is the descending track? So descending to motor packers. And I don't |
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| 28:46 | you to know that details of the pathways would definitely be able to recognize |
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| 28:52 | dorsal column because such a vast area in between the wings. The butterfly |
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| 28:58 | , on the dorsal horns of the cord. Again, techno spinal originates |
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| 29:07 | tech tim is the spine. The spinal, the stimulus Perata's is the |
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| 29:12 | . So I don't want you to the details of this but understand that |
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| 29:18 | you look at the definition cortical it means from cortex to thalamus, |
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| 29:25 | cortical means from thalamus to cortex. , so it's typically the where it |
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| 29:31 | was the first word or the first of the structure where it's going to |
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| 29:36 | second word. The second name of structure. You have the autonomic, |
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| 29:42 | our autonomic visceral nervous system. So a whole projections here that are sympathetic |
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| 29:52 | parasympathetic ganglia. And you can see in green here for example, you |
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| 29:59 | the vagus nerve and you can see vagus nerve innovating the hard components |
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| 30:06 | the visceral components and digestive system into organs. Okay, we don't spend |
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| 30:12 | time about on the peripheral nervous But as I mentioned, the interactions |
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| 30:20 | in the peripheral nervous system interactions and pheasant, terrine nervous system, the |
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| 30:26 | , the gut and the nerve endings . What we call the brain, |
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| 30:30 | axis is the axis between the brain the gut is really emerging is a |
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| 30:36 | important field of study. Okay, now we kind of understand again about |
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| 30:43 | major parts of the brain, the and their functions their locations. We |
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| 30:49 | a lot of different experimental techniques by we can study activity in neurons. |
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| 30:54 | can measure action potentials, we can post synaptic potentials, we can visualize |
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| 31:01 | flux is we can image calcium And ultimately what we want to be |
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| 31:09 | to do is to have clinical tools allow us to measure fast activity of |
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| 31:18 | brain. Most of the imaging that done in the body or the brain |
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| 31:24 | not imaging activity but rather structural So when we talk about imaging the |
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| 31:31 | activity and by the way this is in the Abacus box and the |
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| 31:38 | When you talk about imaging a lot most common knowledge of uh imaging of |
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| 31:45 | structures is probably the yearly checkup at dentist office and the dental scan which |
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| 31:53 | X rays. And when they take rays it shows you all of the |
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| 31:57 | , it shows you all of the structure really well. X rays can |
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| 32:01 | you abnormalities more larger abnormalities in the issue as well. But it's not |
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| 32:07 | good necessarily. And computer tomography or scans are sophisticated X rays that are |
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| 32:15 | multidimensional and their X rays that essentially the structure, different focal points, |
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| 32:26 | angles to allow to recreate the really three dimensional view of the structures. |
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| 32:33 | CT scans again can be used for changes in the bone. If there |
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| 32:39 | any fluid build up near the bone will show up. But if there |
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| 32:44 | masses, abnormal mass formations, tumor in the head or neck. Because |
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| 32:52 | us this is what we're interested in neuroscientists. Then CT scan would also |
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| 32:58 | some of the features of those abnormal formations and tissue formations. Magnetic resonance |
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| 33:11 | . You're not using X rays. you're using a magnet that is detecting |
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| 33:19 | in hydrogen atoms. And you will about two techniques uh that are functional |
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| 33:28 | techniques. So again, if you it's changing the structure of the bone |
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| 33:34 | the tumors such as glioblastoma. So most common brain tumors caused by real |
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| 33:41 | uh you don't know about what is activity changes. How do you measure |
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| 33:49 | in the brain. So later in course we'll talk about E E. |
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| 33:54 | . Electroencephalogram. You put electric recordings measure neuronal activity but you want to |
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| 34:00 | image neuronal activity or neuronal circuit And to do that you can employ |
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| 34:08 | positron emission tomography which is pet or . M. R. I. |
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| 34:14 | is functional magnetic residence imaging. In cases what you're really tracking is regional |
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| 34:26 | flow and brain metabolism. Because neurons are active remember we looked at the |
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| 34:32 | early on and we said oh look part of the brain is active when |
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| 34:36 | person is looking at the words this of the brain is acting when the |
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| 34:40 | is listening to the words and then some other part of the brain is |
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| 34:45 | . So why is that showing up these cans is because active neurons demand |
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| 34:51 | lot of oxygen. They demand a of glucose so they demand food and |
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| 34:58 | and they will be drawing more and food and oxygen. So the neuronal |
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| 35:02 | that are active they will synchronize be and they will sequester more and more |
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| 35:09 | the resources towards that part of the . And then another part of the |
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| 35:13 | becomes active or more active than this . And that part of the brain |
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| 35:18 | sequester the resources through the micro innovating the brain tissue. But Mariah |
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| 35:26 | have a hydrogen atom has one proton between high and low energy states. |
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| 35:32 | frequency at which low state protons absorb is called the resonant frequency which resonates |
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| 35:40 | the frequency the speed at which it between the state two states and there's |
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| 35:44 | death. So uh um it's uh waves by protons and and F. |
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| 35:51 | . R. I. It's a coil. It's similar to pat |
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| 35:55 | It's a magnetic coil that get placed it. And these procedures are pretty |
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| 36:02 | because for having neck scans, the and the magnet space is pretty |
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| 36:10 | So if you have claustrophobia, if have anxiety, other conditions if you |
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| 36:19 | a child it needs to get ahead the next scan done. If you're |
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| 36:24 | elderly person It could be loud some the movement of the equipment around your |
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| 36:31 | . It can take time 20 40 minutes depending on what area how |
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| 36:37 | of the head and neck or the body. Which can these cats can |
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| 36:41 | whole body imaging to not everybody can go through this procedure. Some people |
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| 36:48 | sedated and have to either be lightly or go onto the general anesthesia to |
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| 36:57 | still but then obviously affecting the So if you're getting anesthetized then it's |
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| 37:05 | for imaging some other things like a stroke damage from stroke or abnormal growth |
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| 37:14 | the brain. So now you'll still really nice images and functional. |
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| 37:23 | R. I. Will give you images that we see with pet scan |
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| 37:27 | give you these hotspots. These hotspots say this is stimulation. So when |
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| 37:32 | stimulate the brain let's say this person being told the story and they're listening |
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| 37:37 | talking or listening about the story of to music background and then they turn |
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| 37:44 | the music and the background and they the brain again and you can see |
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| 37:49 | the hotspots have redistributed. So you take the stimulated activity images of activity |
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| 37:57 | subtract them from control images of And the difference will show you what |
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| 38:02 | of the brain were involved in stimulation in this part of the brain that |
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| 38:07 | involved. Ah There is not that of a resolution here. So we're |
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| 38:15 | at single neurons here, we're looking what what is the resolution of a |
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| 38:21 | pixel here? Single pixel is typically one centimeter cute. Okay so you're |
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| 38:33 | at thousands hundreds of thousands of neurons some sophisticated preparations, you may be |
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| 38:43 | to go down to one millimeter which 1000 microns Cell diameter is 10 |
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| 38:52 | You're still looking at hundreds of cells that square area. Okay so uh |
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| 39:01 | area really. So it's a lot cells ultimately we want to be able |
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| 39:09 | do. This is a somewhat noninvasive and that's what I said. It's |
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| 39:12 | difficult procedure. It's not the same your double X ray at the dentist |
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| 39:19 | . You know done you know and sit this this this may take for |
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| 39:26 | emission tomography. You have radioactively labeled with positively charged ions gets injected in |
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| 39:33 | bloodstream. Have to sit around and for about half an hour to an |
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| 39:38 | until you become really hot. And cannot be around other people. You're |
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| 39:44 | to separate room because you're radioactive radio you can be and then it has |
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| 39:53 | certain half life radio activity so it away in your body but it also |
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| 40:00 | for the best imaging. And uh even with X rays or CT s |
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| 40:06 | can also inject contrast into the blood distinguished blood vessels from soft tissue and |
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| 40:11 | the bones. But here you are and you go in and the protons |
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| 40:16 | electrons and admit electromagnetic radiation in the of the photons that get captured by |
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| 40:24 | coil here. And the procedure if you're doing the head and neck |
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| 40:28 | probably about 20 minutes but To wait an hour or 20 minutes. And |
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| 40:34 | these substances get cleared. And not everybody can do this because you |
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| 40:41 | and metabolizes a lot of substances toxins materials. You have kidney that filters |
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| 40:50 | blood. So people that have liver , dysfunctions or compromised livers or kidney |
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| 40:59 | liver dysfunctions. They may not be to go through some of these |
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| 41:04 | And the difference in the two is in pet scans you're looking at the |
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| 41:11 | consumption. So you're measuring two Oxygen, glucose and F. |
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| 41:16 | R. I. You're looking at consumption and you're looking at hemoglobin oxygenated |
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| 41:23 | which will carry oxygen on it. deoxygenated hemoglobin. Deoxygenated hemoglobin. So |
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| 41:30 | part of the brain and the ratio these the oxygenated and deoxygenated the parts |
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| 41:36 | the brain that are active will need lot more oxygen. So they will |
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| 41:42 | higher ratio of deoxygenated human globe. parts of the brain that are not |
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| 41:48 | active will have more of the oxygenated floating around because they're not utilizing as |
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| 41:55 | of it as the parts of the that are being activated. Ultimately uh |
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| 42:03 | techniques are also not very fast. a certain delay even when you give |
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| 42:08 | tasks there's a delay of seconds if hundreds of milliseconds. Ultimately we want |
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| 42:15 | be able to develop technologies that allow to visualize non invasively activity of the |
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| 42:26 | . But all the way down to neuron. Single cell. It's a |
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| 42:33 | complex task to do that. There's machines. These magnets can be very |
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| 42:39 | for M. R. I. hear five T. That's five Teslas |
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| 42:45 | Tesla magnets are very powerful magnets. but hopefully there will be some interesting |
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| 42:53 | and maybe all of you can contribute developing some of them to get to |
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| 42:58 | single cell resolution on a clinical and invasive level. And scientists have been |
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| 43:05 | on this for a good 100 of with electrophysiology and probably a good 50 |
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| 43:13 | years using these advanced imaging techniques. so this concludes our section on the |
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| 43:22 | . N. S. And the of the lecture we will talk about |
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| 43:31 | visual system a little bit and introduce anatomy of the eye. And the |
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| 43:45 | german term gets styled this configuration of . It's everything that you see is |
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| 43:50 | you perceive it. What we see properties of objects in the organization of |
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| 43:57 | by the brain. We have a organization in the visual cortex, we |
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| 44:03 | certain organization in the circus of the . We have three major subtypes of |
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| 44:10 | in the retina. We are limited that. We have three color |
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| 44:16 | Not 16 were limited by three color . We are limited by the |
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| 44:22 | We have two eyes, not That would be cool All the way |
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| 44:28 | like 360 vision. Um We learn lot of things from the outside |
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| 44:35 | We make a lot of assumptions. three dimensions that we are experiencing are |
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| 44:40 | from two dimensional images and we organize sensations into a stable pattern gestalt that |
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| 44:48 | moves around with us as we move it's stable despite variation and the information |
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| 44:58 | . And uh most of the things looking at from a distance, two |
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| 45:05 | . So this is two dimensional. art. Do not mention a |
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| 45:27 | You can fix it quickly. So what what is that? Most of |
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| 45:34 | would say it's a box but it's just a whole bunch of lines and |
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| 45:40 | that are two dimensions. And we this three dimensional structure and understanding just |
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| 45:48 | looking at it. So we make assumptions what is to be seen in |
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| 45:53 | world. And we derive these expectations from experience. So we learn |
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| 45:59 | So we're growing up and apart from built in wiring and limitations of this |
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| 46:04 | and maybe some of the advantages of wiring that we don't understand very well |
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| 46:09 | someday will be even better processing visual . So what are some of the |
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| 46:17 | that we make at the top? have a the biggest pattern B You |
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| 46:23 | this assumption of similarity, which if were to ask you what is |
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| 46:27 | Most of you would say these are lines of blue alternating with vertical lines |
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| 46:35 | yellow thoughts. And I would say about this? And you would |
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| 46:40 | well these are horizontal lines alone, lines in blue. And that's an |
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| 46:45 | that most of us would make in this this this question of looking at |
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| 46:51 | diagram. However, what if the intended that these are horizontal lines with |
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| 46:58 | blue, yellow, blue, blue, yellow and uh this is |
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| 47:03 | columns, yellow, blue, blue, yellow, blue. You're |
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| 47:06 | not looking at that in the same . And so not everybody will see |
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| 47:10 | the same way. Not everybody has same interpretations that everybody has the same |
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| 47:17 | of this similarity assumptions by which we and group things visually together of the |
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| 47:25 | proximity. You just basically bring these closer here and further apart and you |
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| 47:34 | them closer here with further apart in here. Here, you will say |
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| 47:39 | , these are vertical dot lines. are was on a lot lines, |
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| 47:45 | again, it could be the It could be that this is the |
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| 47:50 | pattern. But whoever designed the pattern had this idea about that pattern for |
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| 47:56 | architectural pattern chairs in the building, in the hallway and so on. |
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| 48:04 | have illusions and we also make assumptions we get confused by some of the |
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| 48:13 | we're seeing. But this is one the classical delusions that I'm actually gonna |
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| 48:21 | . So it's the same length, the same like that I'm drawing on |
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| 48:29 | board with this arrow here for this here, but in this one, |
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| 48:37 | gonna put the arrows in like Mhm. And then this one, |
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| 48:45 | gonna put the arrows out like And when you look at the two |
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| 48:54 | and again, if you did not , but I used the same |
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| 48:59 | if you did not know and I to ask you these lives equal |
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| 49:04 | you would say no. The bottom is so much longer and then the |
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| 49:10 | one that's an assumption that you're making you're now seeing something narrowing in going |
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| 49:18 | versus going out. But that's an that our brains make. And then |
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| 49:26 | I'll do is all but the lime and josh wine and it's and |
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| 49:41 | a, you know, rectangle, it's the exact same length with two |
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| 49:49 | too. So we have these things we call illusions. We also learn |
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| 49:57 | things so that when we see people away in the hallway, that's for |
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| 50:03 | , not an illusion. That's not , we don't say it's a much |
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| 50:09 | person because they're hot the whole way , you know, like from the |
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| 50:14 | tale, you know, little but that's not the case. And |
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| 50:21 | , you will probably look at It's the same chair. So probably |
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| 50:24 | same size, same size person just further away, you know, |
|
| 50:29 | This door is big and there's you know, john Malkovich door in |
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| 50:35 | back holiday, you know, So are illusions and once we learn |
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| 50:40 | it's very easy to recognize two surveys, frogs and green fish and |
|
| 50:47 | room. These are very simple And once you see them then you'll |
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| 50:52 | forget it. But there are very ones. And there are three dimensional |
|
| 50:57 | there are even motion. Uh, three dimensional illusions. If you focus |
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| 51:05 | one spot that are quite difficult to all the different parts and pieces in |
|
| 51:11 | . Light comes into the eye and has properties. Its electromagnetic radiation that |
|
| 51:18 | wavelength amplitude and frequency wavelength is here from 407 100 nanometers is our visible |
|
| 51:28 | wavelength is then you can say is color. Uh And the frequency of |
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| 51:37 | wave like it's gonna be. How is repeating the amplitude is gonna |
|
| 51:48 | How strong is the color. So you can when you buy flashlights and |
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| 51:54 | 200 lumens, 400 lumens. So the amplitude. But the color of |
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| 52:01 | flashlight, the wavelength, the frequency be the same. It's just a |
|
| 52:08 | much brighter element for producing the same of life. Uh There is another |
|
| 52:15 | Roy g biv red, orange, , green, blue and violence so |
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| 52:24 | are 400 below that we have ultraviolet rays, gamma rays on the other |
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| 52:31 | of the red. You have infrared , radar broadcast that broadcast bands and |
|
| 52:36 | circuits. We see the world and the world. And these wave lines |
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| 52:42 | and there are animals around us that the world outside of our visible |
|
| 52:50 | And they perceive things differently. And may perceive the world more like kind |
|
| 52:54 | heat maps rather than color maps. eye anatomy that will start discussing is |
|
| 53:04 | of doing everything that you're seeing Actually. You can reflect the balance |
|
| 53:10 | of the light off from a different and bend that light. There also |
|
| 53:17 | . The darker surfaces that are gonna more absorbed. The light, you |
|
| 53:20 | absorb light and when the light crosses between two media such as air and |
|
| 53:27 | will get refracted will get bent. also gonna be bending of the |
|
| 53:32 | not just the reflection bent but bending the light as it's going through. |
|
| 53:37 | that happens so that from the air sun rays light rays enter into the |
|
| 53:46 | and there's a pris environment here. is the cornea. These are the |
|
| 53:50 | sell extra ocular muscles in the back the eye. You have the |
|
| 53:54 | the irises, clara college activa here pupil where the information of the light |
|
| 54:01 | going to enter as that information enters the retina. What we will learn |
|
| 54:12 | the next two lectures is the whole . Today we're just starting to understand |
|
| 54:18 | anatomy of the eye. But if stick with me for the next two |
|
| 54:25 | lectures you understand how this information from I actually is the circus in the |
|
| 54:32 | . What are the circuits the function the circus and the retina. How |
|
| 54:36 | information projects into the lateral nucleus of 1000 books and from there how it |
|
| 54:44 | processed in the primary visual cortex. you should be able to at the |
|
| 54:50 | of these three lectures to understand the and the function of these different circuits |
|
| 54:57 | creating a primal sketch of the visual of the outside world as you can |
|
| 55:05 | the information and the primary visual cortex stop. It goes to secondary tertiary |
|
| 55:10 | the temporary, it actually forms to streams that split. And this is |
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| 55:16 | we're talking about when this visual information gonna get co joined. It's gonna |
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| 55:21 | into the association areas we're gonna get with different senses, different modalities such |
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| 55:28 | hearing, such as touch motor So this bottom part here it goes |
|
| 55:35 | the inferior temporal cortex and is referred as eventual inferior temporal pathway. And |
|
| 55:41 | pathway that the qi is there at top on the left and this pathway |
|
| 55:46 | concerned with processing color information. Form and a little bit of death but |
|
| 55:55 | color and form the pathway that projects the posterior parietal cortex. Up there |
|
| 56:04 | called the dorsal parietal pathway and that is mostly concerned with processing motion, |
|
| 56:13 | and form motion and depth. Interesting the motion part is creeping up closer |
|
| 56:22 | the motor cortex eventually information from what seeing and how you're performing motor tasks |
|
| 56:31 | very importance of you waiting your hands punching people in their face. You |
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| 56:37 | see the distance, adjust for communicate to your motor commands and and so |
|
| 56:44 | have the split going their color. you're listening to music color right? |
|
| 56:51 | thinking about maybe temporal of now you're to involve the areas responsible for hearing |
|
| 56:58 | language speech areas which you're seeing, form, the color becomes important what |
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| 57:04 | write, how you speak also, you describe things. The special |
|
| 57:13 | Visual system you have this canal for drainage. You have lack ramo grande |
|
| 57:18 | produces the um tears you have in front uh here of the of the |
|
| 57:28 | . The Aquarius humor which supplies the and nurses as part of the |
|
| 57:33 | And a curious human impairments can be to glaucoma amongst other things. And |
|
| 57:40 | eyeball shape is really supported by the humor which gives the eyeball this whole |
|
| 57:47 | . The lens as you can is here and it is suspended by |
|
| 57:51 | suspense serie ligaments have axillary bodies and thickness of the lens depends on the |
|
| 58:00 | of these little muscle ligaments. So they contract. If these ligaments contract |
|
| 58:09 | will stretch the lens and the lens become thinner. If they relax, |
|
| 58:14 | lens will relax and become thicker and what helps us focus in a different |
|
| 58:22 | . Is actually changing not only moving head but also changing the thickness of |
|
| 58:28 | lens, which helps us focus in closer or farther away object. The |
|
| 58:35 | is located all the way in the of the eyeball you have in the |
|
| 58:39 | of the eyeball, the optic nerve you also have the vascular system that |
|
| 58:45 | out where the optic nerve exits You have a blind spot because there's |
|
| 58:50 | information processing where the fibers are running . It's called the optic discs in |
|
| 58:55 | area is called the phobia is the is located very centrally right centrally in |
|
| 59:02 | of the pupil. So phobia, you will see contains very high densities |
|
| 59:09 | cone photoreceptors and it's so designed that of the direct axial rays of light |
|
| 59:17 | atomically will be directed into the photo region. So phobia is the highest |
|
| 59:25 | , the highest resolution processing area. that's why when you need to see |
|
| 59:31 | you don't see them while sometimes adding light and directing that light directly into |
|
| 59:38 | phobia helps you resolve and see Okay? I asked security or highest |
|
| 59:47 | vision. As you can see there's whole circuit here in the retina. |
|
| 59:52 | uh I think that uh we will discussing the circuit but this is going |
|
| 59:59 | be the last slide that I show today the information in the, I |
|
| 60:04 | gonna come in the eyeball. You to travel through all that goop. |
|
| 60:10 | until it gets to the back of eyeball, to the retina. In |
|
| 60:15 | retina is gonna encounter forest of neurons gonna penetrate the light. Is going |
|
| 60:22 | travel all the way in the back this retinal circuit and it's going to |
|
| 60:27 | activate the photo receptors. You have photoreceptors and rod photoreceptors. Great labeling |
|
| 60:37 | . Am I going over time? uh coats are blue, red and |
|
| 60:45 | . If you haven't caught on In my test, I may ask |
|
| 60:49 | a question true or false. A choice and then if you go to |
|
| 60:54 | question, there's a diagram. So I ask you questions what types of |
|
| 61:00 | you have blue, red and you can't remember. Maybe you should |
|
| 61:05 | and see if there is a labeling that shows something that indicates that. |
|
| 61:11 | there's a little bit of circularity and of the questions that I asked between |
|
| 61:17 | and especially multiple choice that can help . Also a lot of times read |
|
| 61:23 | question very well because there's maybe something the name of the structure, a |
|
| 61:29 | that's mentioned, not just the answer the question itself that actually has maybe |
|
| 61:35 | hint indication toward the answer. So light comes in from this direction it |
|
| 61:43 | photo transaction process which we'll talk It activates these photoreceptors and information processing |
|
| 61:52 | now going to flow from the back the retina from the receptors photo receptors |
|
| 61:58 | the bipolar ourselves. Remember we talked the different morphological descriptions of cells and |
|
| 62:06 | we talked about pseudo unit polar bipolar , Visa bipolar cells of retina bipolar |
|
| 62:12 | and these bipolar cells are going to onto the retinal ganglion cells and these |
|
| 62:19 | ganglion cells are going to form the of the cranial nerve to the optic |
|
| 62:26 | that is going to exit out of back of the red. Okay, |
|
| 62:32 | first this slide here gets transducer into electrical signal, you have synaptic |
|
| 62:40 | We have synaptic potentials and the bipolar . And the only output from the |
|
| 62:46 | is retinal ganglion cells. The retinal cells now start producing action potentials in |
|
| 62:54 | this stream of processing. There are types of cells that influence the connectivity |
|
| 63:01 | the communication between but the receptors and cells. Those are the horizontal cells |
|
| 63:10 | between bipolar cells and retinal ganglion Those are the hammer green cells. |
|
| 63:16 | we'll talk about their function over the lecture. So this uh uh last |
|
| 63:26 | actually I said it's the last slide this is just what I've discussed. |
|
| 63:29 | should have showed you that slide a bit earlier. You can see the |
|
| 63:33 | ones you can focus in on fire and then thickened bloods or fat runs |
|
| 63:41 | re focus on near earth objects. so that's what I was referring to |
|
| 63:47 | . Okay so when we come back gonna start looking more into this uh |
|
| 63:53 | circuit, finish talking about what's happening the retina. In the circuits while |
|
| 63:57 | create colors. And after we finish we will move into the lateral nucleus |
|
| 64:05 | on up into the primary visual cortex have a great weekend and I'll see |
|
| 64:10 | on Tuesday. Thank you for being today. Those all in class in |
|
| 64:16 | and those all in |
|
