| 00:02 | This is Cellular Neuroscience. It's Monday 20. However, it's our lecture |
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| 00:10 | , not 14. And for lecture , we're going to discuss all |
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| 00:21 | OK. So when we talk about and smell, we are talking about |
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| 00:32 | air, inhaling odor molecules in the through the nasal, through our |
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| 00:42 | our nasal openings into our nasal And here the superior aspects deep within |
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| 00:51 | nasal cavities, we have the olfactory olfactory epithelium, which consists of the |
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| 01:02 | cells that consist of supporting cells. , you also learn sustentaculum cell and |
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| 01:12 | cellar of olfactory cells that are located . It's kind of a little wisps |
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| 01:20 | endings on the olfactory receptor neurons or neurons both used interchangeably. And this |
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| 01:30 | where the binding of the odor molecules this mucous layer takes place to the |
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| 01:37 | receptors uh on the CIA the factory . Ok. So when we inhale |
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| 01:48 | air, these odorant molecules, uh , yes, I think that we |
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| 01:54 | can only see the a a very in syllabus right now. Oh, |
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| 02:00 | you for pointing that out. Give one second zooming this recording now with |
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| 02:08 | image displayed properly as I mentioned, odor molecules would enter into nasal cavity |
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| 02:16 | they can enter by inhalation through nasal through, through our nose. But |
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| 02:25 | part of what we taste. The of our taste depends very much on |
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| 02:31 | we smell. And sometimes we can food through our mouths. So we |
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| 02:38 | our food through our mouths. Some the odor molecules will actually get back |
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| 02:44 | these nasal passages. And uh they still activate the olfactory uh neurons. |
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| 02:53 | shown here in the yellow olfactory receptor or olfactory neurons. And this is |
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| 02:57 | CIA to which the odor molecules combined helping us create that uh perception of |
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| 03:05 | , which a lot of it has do with smell. Because um as |
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| 03:11 | ingest food, we really can only salty, sweet, uh umami, |
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| 03:21 | , bitter, but we can surely a lot of different flavors. It |
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| 03:26 | be salty flavors. Uh It can bitter flavors, some multiple different variations |
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| 03:34 | bitter vegetables and multiple different kinds of vegetables. Uh And that is because |
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| 03:40 | the odor differences. A lot of that allow us to discriminate between different |
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| 03:47 | and between different foods also as we them. So the whole factory system |
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| 03:53 | pretty complex and we're not going to able to understand all of the details |
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| 03:59 | honestly, every time I read and the literature, there's some really interesting |
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| 04:04 | things and some things are still Uh left uh under, under understood |
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| 04:15 | not quite understood. In particular, higher processing of the olfaction. But |
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| 04:22 | you can see in this olfactory which is O E you have the |
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| 04:30 | neurons and these olfactory neurons are uh by S C which is Susten tacular |
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| 04:42 | and by G BC which is globo cells also. Uh and then the |
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| 04:52 | from the olfactory at the helium from olfactory neurons go into the O B |
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| 05:00 | is olfactory bulb and then olfactory Uh The there's a formation of the |
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| 05:10 | nerve which is actually cranial nerve And from there, from these primary |
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| 05:19 | secondary projections from there from the olfactory here shown right here, there are |
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| 05:28 | that spread into many different areas of brain. So they go, for |
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| 05:34 | , into the uh O F C is the orbitofrontal cortex that's involved in |
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| 05:44 | processing. It goes into uh A N which is uh an interior olfactory |
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| 05:55 | nucleus shown here. OK. It into I N which is another cortex |
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| 06:04 | as the insular cortex. Uh It into amygdala which is involved in the |
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| 06:16 | information processing shown here in, in yellow. It goes into the PC |
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| 06:24 | is pure form cortex and E C is enteral cortex and enteral cortex is |
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| 06:37 | the information to H C. The that we know very well. The |
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| 06:45 | and secondary and tertiary projections and go thus, OK. From these areas |
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| 06:57 | and then from thalamus, they project these two other cortical areas. So |
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| 07:03 | mentioned three cortical areas. But you see that some of the projections bypass |
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| 07:11 | and going to the peri form going to the hippocampus. Here it |
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| 07:17 | into orbital frontal cortex from the factory above the projections. Here it goes |
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| 07:27 | amygdala that's really significant because uh hippocampus involved in semantic memory processing. Amygdala |
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| 07:37 | involved in emotional memory processing and In general control of the emotions, |
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| 07:44 | frontal cortex. On these prefrontal cortical are involved in higher cognitive function as |
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| 07:52 | as executive function. Some of these go from into the thalamus from the |
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| 08:03 | bulb. There's another illustration here from olfactory uh uh bulb. Some of |
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| 08:10 | projections through olfactory tubercle go into the and other projections. As you can |
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| 08:17 | , they don't go through the they go to the olfactory cortex and |
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| 08:20 | temporal structures in the pure form cortex and hippocampus that we've discussed. So |
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| 08:29 | almost like there is uh a AAA a bimodal I would say processing and |
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| 08:37 | is not the term that is being but a almost like a bimodal like |
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| 08:44 | of the fact of information. The that requires thalamus and the one that |
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| 08:50 | and engage these other structures. The that requires thalamus, typically, when |
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| 08:57 | gets involved, there is a serious perception of the stimulus and thalamus will |
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| 09:10 | it to the highest or centers as discussed in the Neocortex here and the |
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| 09:16 | factory nucleus and uh insular cortex, am now. So, so these |
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| 09:29 | structures then there's an argument to be that there, there is a emotional |
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| 09:37 | memory and some sort of a executive function then bypasses the actual perception of |
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| 09:49 | through sounds. And that is uh is quite unique. And I think |
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| 09:58 | why I'm saying that there's new information , we're really trying to understand the |
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| 10:03 | between these very complex structures and how affects our smell perceptions, our cognitive |
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| 10:14 | , our motor output, even different . And how as you will see |
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| 10:21 | image actually comes from the supporting literature that I attached for you in your |
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| 10:27 | supporting class literature documents how smell impairments olfactory impairments are also quite strongly associated |
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| 10:42 | are linked to the mental illnesses. . So this is this is really |
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| 10:51 | system. As you can see multiple , multiple nuclei with different functions |
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| 10:59 | It's not just smell. Obviously, emotions, memories, perception of that |
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| 11:05 | comparison, association of that smell with you've learned what you know. And |
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| 11:10 | almost like two bimodal kind of a of process to sing it through |
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| 11:16 | And without thoms. Now, when odor molecules enter the olfactory epithelium, |
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| 11:24 | odorant receptor protein is the one that odor molecules. It's G protein coupled |
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| 11:33 | that produces cyclic A MP. And cyclic A MP opens uh calcium |
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| 11:43 | So this is a olfactory transduction. , the odor molecule activates the protium |
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| 11:51 | a de cycle through the G protein . OK. And the production conversion |
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| 12:03 | A T P into cyclic A MP for influx of calcium. So influx |
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| 12:16 | calcium, then what it does it actually calcium causes some of the |
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| 12:25 | , the major depolarization influx of calcium also chloride opening calcium dependent chloride |
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| 12:35 | And for the chloride actually is a of chloride to be leaving these factory |
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| 12:45 | causing more depolarization. So negative charge . So these are calcium sodium |
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| 12:55 | influx of calcium will open chloride some chloride leaving this time would cause |
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| 13:02 | membrane depolarization. You can see that a Olfa receptor cell here. This |
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| 13:08 | where the SOMA is, this is that are connected to the dendrite. |
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| 13:14 | then these olfactory receptors form the olfactory . Ok. So I misspoke earlier |
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| 13:22 | I said that this is the nerve , the olfactory receptors. This is |
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| 13:26 | formation of the nerve that goes into olfactory bulb. Ok. Now, |
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| 13:32 | the level of the CIA you have potentials. So this depolarization will cause |
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| 13:43 | synaptic or receptor potentials but only through protein coupled activation of these ion |
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| 13:51 | If we're talking about, if there strong enough depolarization, the soma will |
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| 13:57 | action potentials and the factory nerve will these action potentials. So here at |
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| 14:05 | level of the receptor CIA you have potentials and here at the level of |
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| 14:12 | soma and the nerve you have all none action tantrums. Now, what's |
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| 14:24 | and what's interesting about the system? it makes it a very interesting system |
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| 14:29 | study is that each receptor cell expresses single olfactory receptor protein. So here |
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| 14:39 | this diagram, you have the olfactory in different colors, green cyan, |
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| 14:48 | , brown, red. In this , it's an illustrative example showing that |
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| 14:58 | olfactory neurons express different subtypes of these proteins. And if you look at |
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| 15:08 | do we construct or perceive a sense smell? Is it only one, |
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| 15:16 | type of receptor that gets activated to a certain smell? It turns out |
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| 15:22 | for example, if you stimulate these receptors with this citrus odor, lemon |
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| 15:33 | , there will be olfactory receptor proteins are very strongly expressed in these green |
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| 15:41 | that are very strongly reacting to this . And remember it's a chemical |
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| 15:47 | It's a chemical of a certain But there are also these blue cells |
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| 15:54 | express a slightly different odor receptor but it still activates uh it still |
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| 16:06 | to some extent those neurons also the neurons. But red neurons shown here |
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| 16:14 | inactive. They don't react to the smell. If the flower smell is |
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| 16:22 | to these ulfa receptor neurons, green reacted a little did blue, react |
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| 16:27 | lot and red. A little peppermint , a lot, blue, very |
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| 16:33 | red, a lot almond smell, neurons don't react it at all. |
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| 16:40 | , produce a little bit of reaction red has pretty strong reaction. So |
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| 16:46 | that means that each odor smell or of smell such as citrus, floral |
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| 16:54 | almond is mediated by more by activation more than one subtypes of these olfactory |
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| 17:03 | neurons. And they're distinguished. These are distinguished by expressing a dim subtype |
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| 17:09 | factor receptor protein. Ok. All . So this is little factor receptors |
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| 17:17 | form the nerve that goes into the into this area which is located in |
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| 17:27 | factory bulbs. So the axons project and get contacted by the second order |
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| 17:36 | factory neurons and they're in the olfactory and then they will form the optic |
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| 17:44 | . And from an olfactory bulb optic is going to project to all of |
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| 17:49 | various locations in the brain that we discussed that are important, including columns |
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| 17:57 | course and excluding columns, specific mapping olfactory receptor neurons to glo is designed |
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| 18:10 | such a fashion that each one of , this is a factor bulb, |
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| 18:16 | one of these glomerulus that we looked . Each one of these glomerulus receives |
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| 18:25 | only from one subtype of olfactory receptor . So all blue olfactory neurons that |
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| 18:33 | blue odor receptor protium will project into here. The blue one red ones |
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| 18:42 | are located, they are dispersed. can see that within the factory |
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| 18:48 | These cells are dispersed throughout the But then their projections converge onto single |
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| 18:58 | is dedicated to processing information from all cells, all red cells, all |
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| 19:03 | cells, all yellow cells and keep any odor receptor protein that you can |
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| 19:09 | of. Then each one will have own collar that will all converge on |
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| 19:16 | olfactory receptor bones. All right. we will talk about the, we |
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| 19:22 | talked about some of the secondary and projections. But this is really important |
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| 19:29 | there's pathways that bypass thymus and pathways go through thymus into the orbital frontal |
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| 19:36 | . And so this is this this is really interesting to think about |
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| 19:39 | because we don't have this sort of divergence and the processing or perception of |
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| 19:49 | uh or per processing or perception of senses in other sensory systems. So |
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| 19:58 | , uh let's look at some experimental that is uh really neat and |
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| 20:07 | you can work with rodents and rodents really big olfactory bulbs. So it's |
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| 20:12 | well developed olfactory system because they rely heavily on all faction to, to |
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| 20:20 | in their environments. Uh And the interesting thing is that if you want |
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| 20:26 | image activity on the factory bulb, don't necessarily have to pop the brain |
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| 20:32 | of the skull instead in some experimental techniques that were uh you want to |
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| 20:43 | intact animal, which means that the has a nose attached to the olfactory |
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| 20:53 | , nasal cavity and all of that animal. What you can do is |
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| 20:58 | can actually cut a little opening in scalp right above the factory bulb. |
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| 21:11 | then you can shave the skull, can sand down the animal's skull, |
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| 21:19 | in rodents is not very thick until becomes super, super, super thin |
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| 21:26 | if it was just a almost a like translucent layer. So it's minimally |
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| 21:36 | because you're just cutting the scalp or skin right above the bulb or factory |
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| 21:43 | and you're shaving or sanding down the actual skull bone so that you can |
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| 21:52 | the factor evolves in the intact You can now subject that animal to |
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| 21:59 | smells. In this particular figure. have minty and fruity smells. |
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| 22:07 | minty smell will have a certain chemical as you can see. And fruity |
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| 22:14 | will also have a certain chemical And in fact, there these two |
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| 22:21 | are are quite similar. You're just AAA ach three here. OK. |
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| 22:28 | the uh versus the isopropyl. So what kind of map if you expose |
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| 22:40 | animal to minty smell versus Scroti What kind of map of activity we're |
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| 22:45 | very familiar. You can use voltage dyes, you can use intracellular calcium |
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| 22:52 | in this case. So calcium why? Calcium? Because it's a |
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| 22:58 | tool in this situation. As a of calcium enters into the factor receptor |
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| 23:05 | . And there's a lot of calcium signaling and in general increases in calcium |
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| 23:13 | to activation of cells. But you use voltage sensitive dim and you could |
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| 23:19 | genetically encoded voltage indicators that we talked . And now you're subjecting the animals |
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| 23:26 | different smells and you can look at map of those odors. So this |
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| 23:30 | the map of minty smell. You see very clearly. One glomus is |
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| 23:35 | , very active, maybe two or more or 44 or five more are |
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| 23:41 | to a certain extent the fruity Again, you see one glo Mario |
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| 23:46 | very, very active next to There are very active blue Mario and |
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| 23:51 | of them are activated. And this the Gloria map for minty smell gla |
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| 23:58 | for fruity smell. And in then what you could do potentially is |
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| 24:05 | you can get down to a uh resolution of a single cell is in |
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| 24:13 | diagram here on the right. You see that yellow color are neurons that |
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| 24:20 | activated, green color neurons and red neurons. So green color neurons are |
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| 24:27 | of the ones that were activated by smell or piny smell. And you |
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| 24:35 | look at this map of olfactory cellular and also in the olfactory cortex. |
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| 24:41 | doesn't have to be done in the ball factory cortex. Obviously, you |
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| 24:45 | have to do a more invasive technique uh opening up the, the skull |
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| 24:50 | lot more than just here shaming the the the the skull to visualize the |
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| 24:56 | balls which are just underneath the skull . So all of these cells green |
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| 25:02 | the map for pines, red is map for fruit and citrus yellow are |
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| 25:09 | that were overlapping. They're reacting to and and citrusy smell and cut |
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| 25:18 | This is a map of cut grass the cellular level and this is a |
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| 25:22 | of the fruit and there is a less overlap between cut grass and fruit |
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| 25:28 | you see a lot less of the cells which are responding to both green |
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| 25:33 | red. So by this virtue, can have these olfactory activity maps in |
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| 25:41 | glomus and in the olfactory cortex. this is not just in animals where |
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| 25:50 | can image of course experimentally in We can image uh using these beautiful |
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| 25:58 | neuronal activity, voltage, calcium uh sodium techniques, but we can also |
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| 26:10 | it non invasively in humans using functional resonance imaging. So if you recall |
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| 26:20 | and F MRI, the two functional clinically relevant imaging techniques in humans. |
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| 26:30 | in this case, this diagram here a person smelling a rose, a |
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| 26:38 | can be smelling a mint, a , a lemon. And first of |
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| 26:46 | , there is a map of that , which is the active neuron man |
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| 26:56 | is created in the olfactory bulb. that map from the primary and secondary |
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| 27:05 | neurons and then later to the tertiary onto the projections throughout the brain will |
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| 27:13 | a distinct neuronal activity in the map is way, way much wider than |
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| 27:20 | factor the bulb or just the It will involve all those other structures |
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| 27:25 | we discussed at the very beginning of lecture. And beyond that, it |
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| 27:31 | also involve the structures that are connected interconnected with the factory system. Uh |
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| 27:43 | structures are now the associated structures, very strong component in the in the |
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| 27:50 | lobe. As you can see uh strong component still in a lot of |
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| 27:55 | subcortical structures that we discussed again in activation. But what I like to |
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| 28:02 | out when I show students this diagram so do you still think that smell |
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| 28:09 | just a pleasant odor? And if show you this map of physiological changes |
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| 28:19 | the brain activity as a consequence of smell, that means that if you |
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| 28:27 | into a spa with aromatherapy of eucalyptus or or something like that, that |
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| 28:40 | create a certain math in your brain that may change your behavioral and motor |
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| 28:50 | . If you walk in an environment the smell is unpleasant, his nauseating |
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| 29:02 | , you will evoke not only an map in your brain but subsequently based |
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| 29:10 | that such information, a physiological emotional and motor responses. Ok. |
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| 29:24 | smells are very, very important. fact, smells might be one of |
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| 29:30 | most important determinants in selecting a Although we may not want to think |
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| 29:39 | it, but it is important and relationships don't go well, if there |
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| 29:47 | no smell or smell perception, compatibility. A lot of times people |
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| 29:56 | chemistry, well, there is the , inhaling chemicals. It's activating your |
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| 30:02 | maps and it's causing a certain behavior motor response. No. Next what |
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| 30:16 | if you have a smell disturbance? that comes from the um literature that |
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| 30:24 | included for you to look at as supporting class literature. Just one |
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| 30:30 | one review article. And as I , today's life show is probably gonna |
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| 30:35 | a little bit shorter, but let's about that. So first of |
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| 30:42 | let's talk about something that is quite these days because we have all gone |
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| 30:55 | COVID-19 to 1 extent or another. was infected with COVID-19. And when |
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| 31:03 | had COVID-19 infection, which also can your systems. Tacular cells as C |
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| 31:12 | and your olfactory neurons, eventually it lead to anosmia which is a complete |
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| 31:22 | of olfactory ability. In some A smell, the stones can be |
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| 31:30 | hyposmia which is decreased or factor So what is the difference between the |
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| 31:37 | ? The difference between the two is if you stick your nose into a |
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| 31:42 | of gasoline and you cannot smell anything a nice meal hyposmia is that if |
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| 31:52 | have your nose far away from a of gasoline, you may not smell |
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| 31:58 | , but as you bring that can , you put your nose in |
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| 32:03 | You know, the decreased the factor , you perceive the small smell of |
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| 32:08 | and gas, chemical smell, the rare disturbance is hyperosmia, heightened ul |
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| 32:17 | ability, which is less common. . How does that happen? Let's |
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| 32:24 | about it. Do we all perceive mouse in the same way? Do |
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| 32:30 | all find? Maybe we do somebody can say that? Ok, |
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| 32:38 | can perceive the smell of uh and can perceive a smell of banana. |
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| 32:52 | , uh uh both smells are gonna agreeable to everybody. Some people will |
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| 32:56 | I hate but can't smell it. know, bananas, I love some |
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| 33:00 | will say both others will say only bananas smell. Why is that? |
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| 33:07 | don't know a lot of it. course, is that behavioral maybe |
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| 33:12 | maybe um cultural geographical, the smells used to um um certain smells are |
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| 33:26 | strong for people from other cultures and it's vice versa. They can be |
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| 33:34 | for other people from other cultures and on and so forth and, and |
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| 33:38 | on. Now, does that mean we have slight variations of called factor |
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| 33:44 | protein expressions? Probably. Yeah. about wirings? Ok. That's |
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| 33:51 | What happens if you lose your And anosmia and COVID-19? Did any |
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| 33:58 | you lose a sense of smell. . One, I actually didn't. |
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| 34:07 | , my sister did and it took a couple of months to finally smell |
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| 34:13 | . She had lost the ability to , to gain it back. A |
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| 34:16 | of times that depends on, in COVID-19 specifically, that depends on |
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| 34:21 | we call the viral load. How of that virus got into the |
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| 34:27 | How bad was the infection? And viral load depends again on how much |
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| 34:33 | get into the system and how well system can defend itself with the immune |
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| 34:39 | against the invaders. Like a I lost my sense of smell for |
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| 34:44 | a week. Now, this is interesting thing that happened to me in |
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| 34:48 | last uh year and a half. lost my sense of smell three times |
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| 34:54 | . I lost it in the evening into the night and in the morning |
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| 34:59 | when I was going to test for one time, it came back and |
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| 35:04 | time, it also came back the day the following morning and I tested |
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| 35:09 | for COVID-19. That was interesting. I think that I actually may have |
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| 35:15 | COVID-19 infection, but it was very lived and I fended it off until |
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| 35:20 | finally, I got sick last December sense of smell for a week and |
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| 35:26 | started irritating me. Uh It started me psychologically started uh making my world |
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| 35:37 | very bleak and bland. It's the , those flavors that I'm talking about |
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| 35:45 | reduced to salty, sweet, bitter mommy. But, but you |
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| 35:53 | you can no longer tell that this salmon, salty, salmon versus salty |
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| 36:00 | and all of that because the sense smell, beef jerky is a sense |
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| 36:05 | smell is gone. Yeah. Now talk a little bit about like then |
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| 36:12 | came back. So, and it back and your sister, you |
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| 36:19 | uh, Elliott, I think, two months for it to come |
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| 36:23 | Yeah, it, it took Yeah. So, go ahead. |
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| 36:31 | took me about a month for any at all to come back. |
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| 36:37 | er, I guess smells, but for like a year I |
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| 36:42 | I was smelling things differently like egg, smell like armpit. |
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| 36:47 | My sister's in the same boat. she used to eat smelled very differently |
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| 36:50 | she just stayed away from them and took about a year, uh, |
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| 36:56 | be coughing anymore. So, Factor has a half life of one |
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| 37:04 | Is that interesting? You guys said month and you said two months for |
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| 37:09 | , I guess it's faster. It a week. Maybe it was |
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| 37:13 | maybe I fended it off because I fully vaccinated and boosting my, for |
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| 37:19 | . So, what does that You can actually regenerate of factory neurons |
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| 37:26 | then you can rebuild their nerve endings . Uh, and we'll get back |
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| 37:33 | the, the smell discrimination, something you already mentioned. So it's uh |
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| 37:37 | thing is to not have smell, thing not be able to discriminate different |
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| 37:43 | . So one could make an What about hyperosmia? You know, |
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| 37:47 | are usually people with really, really noses. I wish I had |
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| 37:51 | And uh they seem to have uh don't know, maybe greater number of |
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| 37:58 | receptor neurons, maybe more sillier, somehow their uh a mucus is different |
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| 38:08 | the olfactory epithelia. So it allows the passenger motor molecules easier. I |
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| 38:13 | know what the reason is being the behind high. Is it regenerating |
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| 38:21 | So the half life is like two or something. And actually it turns |
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| 38:27 | we switch which nostril smells passes the faster and which passes the air slower |
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| 38:34 | it switches every few hours between left right and back. OK. But |
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| 38:40 | are the common disturbance system that we're about. And obviously, it's way |
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| 38:44 | rare to have somebody with patent a ability and we also don't have a |
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| 38:51 | code for perception of smell. So you're into biomedical engineering or something like |
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| 38:57 | , I think this is very Can we build a robot that can |
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| 39:02 | the smells? There are robots that recognize the toxic uh chemicals and |
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| 39:09 | but I don't think there are robots can tell the difference between lemon and |
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| 39:15 | , you know, or passion fruit Guam, whatever it may be. |
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| 39:22 | . So this is the common disabilities disturbances. Uh for some reason, |
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| 39:28 | is a little bit uh but there significant uh associations of uh um I'm |
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| 39:41 | to exit this. So, hold . Give me 1 2nd. |
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| 39:47 | So small deficits are about 20% of population. So 11 in five may |
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| 39:57 | a small, small deficits. You , it's interesting, maybe some of |
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| 40:02 | already have these deficits. So when get an infection, it takes us |
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| 40:06 | to recover or longer time to Uh one would argue that discrimination of |
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| 40:13 | , which is recognizing something that you've before really, right? Citrus like |
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| 40:18 | versus lime, for example, or versus grapefruit. Um and that's discriminating |
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| 40:27 | lemon and grapefruit. Now that involves of multiple olfactory receptor neurons, ol |
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| 40:34 | receptor subtypes. And that means that in some instances where the eggs are |
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| 40:42 | like armpits or things like that, is maybe there is a recovery of |
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| 40:48 | factor receptor neurons on their proteins to to whatever level of pre infection faster |
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| 40:55 | compared to some others, it may taking longer time. And so now |
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| 41:00 | can imagine that that smell, you floral smell. If you're still missing |
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| 41:07 | red, it, that floral smell be very similar to citrus smell. |
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| 41:15 | ? And only a month or two later, when you have enough of |
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| 41:19 | red, it'll affect the receptor neuron . Now you can definitely tell the |
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| 41:23 | between citrus and floral smell. Does make sense? So now, uh |
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| 41:33 | , the review that I included for is uh how olfactory dysfunction is linked |
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| 41:39 | the psychopathology of mental illness. And we talk about uh clinical populations and |
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| 41:52 | you talk about how you test it's typically threshold or detection discrimination and |
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| 42:03 | . So threshold is relates to smallest of the r odor that you can |
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| 42:10 | discrimination is the the ability to distinguish or more different orders. Identification is |
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| 42:18 | most commonly used test is the ability detect, identify and name a sound |
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| 42:26 | o identification and o discrimination rely more cognitive functions. So specifically more on |
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| 42:35 | pathways, the semantic memory pathway, is a hippocampus pathway as compared to |
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| 42:43 | threshold tests. Ok. Because er you to have identification discrimination, you |
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| 42:52 | to have a memory of a require a knowledge of a particular scent |
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| 43:00 | memory of a particular scent or experience that particular scent. And that would |
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| 43:06 | again looping through the hippocampal pack mental that are associated linked to impairments and |
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| 43:22 | . And they can be again, three types of impairments and smells can |
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| 43:30 | threshold discrimination, identification. You could a a failure among those three |
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| 43:41 | The mental illness is anxiety, schizophrenia and bipolar disorders. And there |
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| 43:52 | different variations of what happens in these disorders and there's different ways in which |
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| 43:59 | being tested for. That article describes in greater detail. But in |
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| 44:05 | these are the things that I'd like you to know that there's strong association |
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| 44:09 | people that have a different discrimination, , identification of orders and sometimes odor |
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| 44:20 | are being used to diagnose and sometimes predict maybe early um diagnosis, noninvasive |
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| 44:31 | of, of, of mental illness depression. Very, very uh uh |
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| 44:39 | is very strongly linked to um some smell perception, alterations of smell |
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| 44:49 | and what could be the cellular and mechanisms that lead to to, |
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| 44:59 | to this. And in particular, the olfactory system, inflammation seems to |
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| 45:06 | one of the main causes the inflation the olfactory epithelium in formation of the |
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| 45:16 | receptor neurons seems to contribute a lot not having either threshold identification or discrimination |
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| 45:29 | . Inflammation is if you recall microglial , cytokines, they control cytokines and |
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| 45:39 | abnormal levels of cytokines and you have and and mental illness neurogenesis. So |
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| 45:49 | new neurons are born, they're born the zone called sub ventricular zone or |
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| 45:57 | V Z. And from that subculture , those new neurons migrate into the |
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| 46:04 | bulb and maybe it is the neurogenesis that is not necessarily uh directing the |
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| 46:16 | in the correct locations, structural and changers. So with inflammation, you |
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| 46:28 | have changes in connectivity, you could structural changes due to different things due |
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| 46:36 | trauma due to infections. Uh or to the inflammatory process, disregulation at |
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| 46:45 | , at the level of the of brain cells. But you can imagine |
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| 46:52 | you have differences here in connectivity between red and blue and green cells, |
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| 47:03 | the wiring is very important here. migration of the cells is very |
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| 47:09 | So the wiring and the connectivity if changes and if you're missing a factor |
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| 47:16 | protium, you could be living in world where you cannot discriminate between owners |
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| 47:23 | well or where you have a very perception of odors from others. And |
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| 47:30 | why in, for example, certain people with mental illnesses have very strong |
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| 47:40 | that may be around them from their or from their hygiene, but it |
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| 47:45 | not bother them at all. So misperception, this mis wiring information and |
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| 47:55 | processes get called misperception of odors. of us would think that, you |
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| 48:03 | , bathrooms don't smell good and the that misperceive that they think that |
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| 48:10 | you know, like a perfume counter Marcus or something like that. So |
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| 48:18 | you have it. So please look this article that I'm talking about and |
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| 48:26 | talks specifically about mental illness and it about these different pathways as they process |
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| 48:33 | information. And this is in addition the slides, in fact, these |
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| 48:39 | that I'm showing you, they're already on your power point. And there's |
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| 48:44 | very last slide for the last couple minutes. I'd like to, to |
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| 48:50 | you that what we smell every the most small volatile molecules are the |
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| 48:56 | chemically. So you can see that of these chemicals have complex and long |
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| 49:02 | . So those are simple and shorter to interact with the odor, separate |
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| 49:07 | and the shorter the molecules, the volatile they are in, in perfume |
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| 49:15 | or in candle industry or whatever they're to as the top notes. And |
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| 49:23 | after that, you have longer molecules are longer carbon chains because there are |
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| 49:29 | chains here that we're talking about c . These carbon chains are longer and |
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| 49:36 | called heart notes. And typically, you're smelling something that has heart |
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| 49:40 | the smell may persist for a longer , minutes of hours, the longest |
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| 49:47 | no persists for hours or days. cannot perceive odors that are 16 carbon |
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| 49:57 | or longer. So over 16 carbon , we cannot perceive the smell. |
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| 50:04 | one of the strongest smelling plants on is cannabis and we cannot smell |
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| 50:15 | the active ingredients in cannabis. Uh we smell odor molecules that are called |
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| 50:24 | and that's what the tarp stands It's a volatile odor molecule. Tarps |
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| 50:31 | present and everywhere around us and fruit vegetables, we consume them and eat |
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| 50:38 | , but they're also dominating odor. this is the only odor perception we |
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| 50:46 | in the cannabis plants as well or other plant for, for, for |
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| 50:52 | matter that contains molecules that are longer 16 carbon long chains and cannabinoids are |
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| 51:02 | typically 22 carbon long. All So we will end our lecture here |
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| 51:11 | . Thank you very much for joining online. I appreciate everybody being |
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| 51:16 | Please review the figure in the article the major mental illness conditions in these |
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| 51:25 | of threshold discrimination, identification and potentially causes of uh psychopath psychopathology, psychopath |
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| 51:39 | physiology of uh odor disturbances. All . Thank you very much and I |
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| 51:47 | see everyone back in school on Wednesday campus. Take care guys. Thank |
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| 51:58 | . Thank you, Doctor |
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