Neuro 11:3: Memory Systems and the Brain PDF

Created with Coconote - https://coconote.app Neuro 11: 3 But I'm gonna try not to do that. Okay. So what we're gonna do now is we're gonna talk about, the areas of the brain that are involved in different types of memory. And I'm not gonna talk about them all. I'm just gonna talk about explicit an...

Created with Coconote - https://coconote.app Neuro 11: 3 But I'm gonna try not to do that. Okay. So what we're gonna do now is we're gonna talk about, the areas of the brain that are involved in different types of memory. And I'm not gonna talk about them all. I'm just gonna talk about explicit and implicit memories. And then I have a really, I think, really interesting videos. Video, of an individual with amnesia, a very severe form of memory impairment that really highlights how these memory systems can break down. So in terms of what areas are involved with memory, the biggest association has been between long term explicit and implicit memory. The areas that are important for long term explicit memory are 3 different regions. The temporal lobes, both of them, left and right, and proximal or neighboring regions. So here we're looking at the undersurface of the brain, and this is the temporal lobe down here. And the temporal lobe is important. The entorhinal cortex, which is a specific, part of the temporal lobe on the inferior surface here is very important. We mentioned it, last time or the time before when we talked about Alzheimer's disease. It's one of the first areas that's affected in Alzheimer's. The parohippocampal cortex, which is a gyrus right next to the interrhinal cortex, the perirrhinal cortex, the hippocampus, which is the seahorse type structure that's wrapped up into the temporal lobe, and the amygdala as well. So these areas of temporal cortex and neighboring regions, hippocampus and amygdala, are critically important in long term exposive memory. Also important is the prefrontal cortex. And third area that's important as part of this circuit is the medial thalamus. The medial thalamus is a specific nucleus in the thalamus. You'll recall that the thalamus, one of its major roles is it serves as a relay station for sensory processes, also serves, in motor function as well. It plays a really important role in many cognitive functions as well, and it still acts as a relay stop. What it is is it's what hooks up the temporal lobe structures to the prefrontal cortex. So the medial thalamus loops them together into a network. So this is from your text, and it shows, how an explicit long term memory would be laid down in the brain. And I think the best way to work through this is for someone to come up with an example of something that's happened to them recently. If you can't come up with an example, I'll think of something from my life. Come tell me an example of something that's happened to you recently that involved a whole bunch of sensory and motor things. Things that you saw, things that you heard, things that you smelled, things that you tasted, motor things that you did. So every event in your life can be coded in terms of sensory processes and motor processes. Right? Like, everything involves sensation and most things involve motor activity as well. So tell me something that happened. Okay. I recently moved, so I had to, like, bring up my handsets since we're moving in there. So I've lost a lot of motor and sensory and you can see things. It's really nice. Okay. So tell me tell me some really specific examples. So tell let's let's look at vision. What did tell me one thing you saw. Furniture. Okay. Furniture. Something that you smelled. Well, it's a different house, so I could smell it. It smelled different. It smells a little bit more. Okay. Something that you heard. The vacuum going. Okay. They're cleaning the other house. Okay. Was there was taste involved? Not really, but we stopped for lunch. So I guess it's fine. And what's the last sense? Odor? No. Sense. Vision. Oh, sensor. Vision. Did I say vision? Yes. I heard you. Touch. Touch. Yeah. Feelings, things. Yeah. So cardboard and tape and Yeah. Exactly. All those sensations. Okay. But, you know, the metal of the scissors when you're cutting the boxes and okay. So you've described all the sensory things and then give me a couple of motor things as well. Moving furniture, like, vacuuming, all the necessary. Wonderful. Okay. So there's something that happened, and it's been described in sensory and motor terms. If you want to lay that experience down in your memory, what we need is we need your brain stem to have basically allowed you to have paid attention to it. So it does say you were in, like, you know, a like a super, super, like, sleepy and inattentive and, like, you were just not paying attention to what was going on. You were just, like, mentally vacant. Would you remember this event of moving, like, 5 years from now? Probably not. The more attentive and the more you were tuned in to what was happening, the stronger the memory. So that's what this arrow was showing here. There's lots of other cortex involved beyond the sensory and the motor acts. So was language involved? Was visual perception involved? Was, like, praxis, like, you know, coordinated motor acts involved? Was executive functioning involved? Yeah. Yep. So whole bunch of other cortical processes were involved. And this event, especially since we've talked about it now for 5 minutes, is gonna be laid down in your memory for a since we've talked about it now for 5 minutes, is gonna be laid down in your memory for a very long time through this circuit here. So the temporal lobes is where the actual, like, memory gets laid down with, you know, the firings of neurons and connections, between, different neurons, in these areas here. The prefrontal cortex plays a really important role in organization, screen there, also was linked to the, you cleaner, also was linked to the, you know, the sound of, you know, the tape as you cut it. They weren't discrete events. They were all linked together and organized. And the prefrontal cortex, because it's really important in executive function and organization and planning and all these higher level things, pieced all these events together. And then the medial thalamus act as the as as the connector between these two areas. So there we have a long term explicit memory that you will never forget now nor will the rest of us. So and that's very different than something like doing, you know, the tower of Hanoi task where you have to move the dowels over, in a certain number of steps, or learning to ride a bicycle, or learning to play the violin and getting better with experience as you practice this sequence of, you know, finger movements. Long term implicit memory, and I don't have a picture that shows this, but what it depends on are the motor pathways, especially the basal ganglia and the cerebellum and their connections to the cortex. And it there's pathways to the thalamus as well, but it doesn't involve these temporal lobe structures. These temporal lobe structures are uniquely involved in long term explicit memory. So a little bit more about memory. Memory different memory systems can be selectively impaired by damage. And when you have a memory impairment, it's known as amnesia. You can also have a distinction of memory type based on whether it's a new memory or an old memory impairment. So this is showing a timeline. And if this is the future and this is the past and this is the time at which someone sustains something to their brain, and that might be a traumatic brain injury. It might be a stroke. It might be the onset of a degenerative, process like Alzheimer's disease. Here's when the brain event happens. Difficulties laying down new memories after the time of the stroke or the onset of the Alzheimer's disease or the traumatic brain injury, those difficulties are referred to as anterior grade amnesia. So if someone's in a nursing home and they have Alzheimer's disease and they've had Alzheimer's disease for 5 years and they can't remember what they had for breakfast that day, that's an anterior grade memory impairment. What a retrograde memory impairment would be would be if that same person can't remember, the names of their children and they had their children and named them before the Alzheimer's disease started or they can't remember the town of which they were born. Old memories are referred to as retrograde memories, and impairment in them would be retrograde animation. I'm just wondering, like, is the difference between the 2 that, like, anterograde, you're having difficulty consolidating whereas retrograde, it's like re like bringing the information down. Probably. Yeah. Exactly. So with anterior dysplasia, in the case of Alzheimer's disease, we know people have, like, just terribly degraded temporal lobes in all of these areas here, and so they can't even get the memories in place. That's different than not being able to recall them from the past where the memories are there, but they can't pull them out. So it's I think it's it's not quite that clear cut, but, Brynn, what you're saying is is exactly right. Mhmm. Within retrograde amnesia, you can see a gradient of impairment sometimes too, where the closer you get to the time of the event, the more things are effective. And the more you go back and pass, the better they're preserved. So you might see people re being able to remember the town that they grew up in, the house that they lived in until they were 5 years old or 10 years old, but they can't remember where they went to university. They can't remember their, you know, their wife's sister that they met, you know, 30 year or 20 years prior to the onset of the Alzheimer's disease. You see this this gradient of impairment. And I know you're all pressed for time, but when you have some time in future, there's an Oliver Sacks story. It's called The Lost Mariner. It's about someone who has amnesia, and it's really interesting. He has this really profound form of amnesia, and there's a timeline. He can remember up to I think it's about, like, 25 years of age in, like, really, really vivid detail. And then at around 25, his memories pretty much stopped. And he had a really severe form of amnesia from something called Korsakos disease, which is actually from it's a from a vitamin deficiency. If you have really, high levels of alcohol use for years, it breaks down, you have a thiamine deficiency, and then what happens is the medial thalamus breaks down in the mammillary bodies, and people can be left with just profound endings. But what's interesting, and this is not uncommon, is there's this gradient. There's this point at which the memories just stop, and nothing after that is accessible. And you'll see some examples of this in the video that I'll show you as well. So yes. I don't I think it's gonna vary from person to person. And I don't think it's necessarily gonna be, like, it can be a, like, a rough timeline, but there might be some memories that kinda dip down below and then some that dip up. Like, if something was really emotionally salient, then maybe it could be, like, you get closer to this point in time. Whereas if something didn't have a lot of significance, maybe it would be something that's, like, more down here. So it's gonna vary. It it's it's really it's interesting to see the things that get preserved versus the things that are lost, because it's not always the things that you'd expect. People can remember sometimes really vivid details about their their childhood pets, and yet they can't remember their mother. So you think, well, you have lots of memories associated with your mother, but with your pet, you know, there it's very pure or a child and you had a dog. There's so many there's probably so much joy involved with that and, you know, sensory things as you get licked and your dog smells and so you remember the stink of your dog and, like, all these things. So I don't know. It's and it varies. Yeah. From experience, like, my grandmother has Alzheimer's, and she still thinks I'm in high school. So every time I see her and I don't get to see her a whole lot, but every time I see her, I kinda have to re explain that I've already graduated with a degree, and now I'm in grad school. But also, like, when we would go visit her, so usually it would be over a weekend. Every day that we would go visit her would be kind of like a new experience. Like, she wouldn't remember from the day before that we had already been there to visit her. So she would be more kind of like surprised and excited, which was good to see, but also kind of sad because she would remember us visiting the day before. So Yeah. So thanks for sharing that because that's actually a really good example too because it shows that her memory she can remember you, but the memories are stuck somewhere down when you were in high school. Yeah. She can't lay down new memories because then you keep correcting her, but she can't Yeah. Score that. And then sometimes what you see, I don't know if it's the case with her, but sometimes people who will have Alzheimer's disease or another, you know, stroke that leads to a a major memory problem, implicit memories can be so well preserved. So they might be able to knit these really complicated knitting patterns. You'll see that sometimes. Or they can still cook in the kitchen. They can't remember that they put something in the stove, but all the things from memory about how to bake a cake, they can just automatically do. One thing I noticed too, and, like, my mom used to work in a nursing home. She mentioned, like, when she would work with you who had Alzheimer's, their taste changes a lot of the time too. Is that more something Their taste? Yeah. So, like, things that they used to like, they don't necessarily like anymore. Is that just because of, like, because as we get older, like, our taste buds do change? Or does that have to do with the memory loss as well? I think it's more sensory, but I'm not actually sure. And you see that with Parkinson's disease too, and I I don't know what the mechanism is, but I've heard of many people with Parkinson's disease who really their taste preferences really change. I don't know. I don't know what it underlies that, but it's not uncommon. You know? Just to answer the question a little bit, I worked in a nursing home for a few years. And for the taste, yeah, it seems like some, like, aspects of taste, like, kinda start to fade before others and others kind of stay prominent. So, like, like sweet things, like sugar, for example, stays around a lot longer, so we'll have more preference for that. Mhmm. And do you know like, is it is it actually like, is it related to taste buds or is that at a higher level? At least from what I've heard, it is like a is it is it taste thing? Right. So they can actually like, those ones stay longer or something. But it's at a receptor level, isn't it? Yes. It's not at a brain. Yeah. Yeah. Anyways, great examples. Thank you. So probably the most famous patient with memory disorder was h m, and he's talked about a lot in his textbook. How many of you have heard of h m before? Great. So I've don't and I've talked about him lots before. He was probably the most famous amnesic patient ever. He had a very severe case of anterograde, explicit, memory, difficulties, and this resulted from he had temporal lobe epilepsy. They didn't know at this point in time when he had his surgery. I think his surgery was in the 19 forties, that the really critical role that the temporal lobes and the hippocampus played in memory. And so they took out bilaterally his hippocampi and adjacent temporal lobes. You can see what his brain would have looked like here. And he was left with a profound, profound, memory impairment. So, apparently, he would be in the hospital, and a nurse would walk in and she'd introduce herself. She'd come back in 3 minutes later. He had no memory of ever seeing her before and thought that a stranger was entering his room. He would eat his breakfast then he'd ask, you know, 5 minutes later for breakfast because he didn't remember eating his breakfast. However, he was able to do some really neat things like the tower task that I told you. He was able to figure it out and then get better. And when he was given the task again, he remembered his brain remembered doing it because he could do it more quickly, but he would say, oh, I've never seen this before. There's another task called mirror tracing where there's a mirror and you have to trace something. So you have to make your motor act opposite of what you're seeing, and I've tried it. It's kinda tricky, but as soon as you get it, you can it's really easy. And, again, he could learn this, And then when he was given the task again, he was quite skilled at it, but he would say, I've never done this before. So all sorts of implicit things he was able to do because those circuits were impaired? Yes. Absolutely. And so in something like Alzheimer's disease, what is most affected is explicit memory. As time goes on, semantic memory will be affected as well, but people can have, you know, quite good understandings of the world around them, but they can't remember what they had for breakfast or that their daughter came to live with them. But they could tell you about, you know, a whole bunch of details about, farm animals or, there those of you who are in the the speech program, we will go to Maplestone, long term care facility, and, hopefully, next term, and you'll do an activity there with a resident. There was a gentleman there for a number of years who was an auto mechanic, and he wouldn't remember people the students from week to week. He wouldn't remember the people that were caring for him, but he could tell the students so many details about cars and how to repair an engine and all these things that were probably procedural, but also some magic too. Like, there's a standard way to repair an engine, and those were still with them. So you can see dissociations between episodic and semantic, like, absolutely. Okay. And then with HN as well, emotional memory seemed to be preserved. He He knew who he liked. He couldn't say why, but he had strong emotions attached to people and events. One last dissociation, and then I have a video that highlights these things really nicely. Was there another question over here? Yeah. I it wasn't me that had my head. Okay. So if someone else has a question, I'm not sure. But I was also just wondering, like, do you think part of the reason why HMs memory loss was, like, so profound even compared to, like, other things like TBI and that sort of thing is because it was so, like, surgically precise? Because I'm just kind of thinking again of, like, how the brain is, like, there's, like, a lot of association and, like, cross wiring and redundancy. But because it was, like, such a, like, clean precise removal, whereas, like, if you hit your head, like, you know, there might be a few pieces still left. Yeah. Absolutely. So they, like, physically took out those areas, and it was symmetrical. And I think there'd be no other the only other, well, I shouldn't say this absolutely. One other form of brain damage that can lead to that severity, which is, what the gentleman in the video that I'll show you in a minute has is herpes simplex encephalitis. I don't have a brain scan to show you, but the way that brain infection happens, essentially, it completely eats the temporal lobes. And if you look at an MRI, there's there's big empty spaces. There's no temporal lobes. And I have seen patients who have had it, and it's been like Like, just memory is complete this form of memory is completely gone. And their brains, like, they're they've lost their temporal lobe. So in many cases, like, it was removed surgically, but with herpes simplex encephalitis. And I can't remember. There might be a brain scan shown in the video. It's the virus has taken the the tissue out. But Alzheimer's disease is more subtle. As it's happening, there's probably some plasticity occurring, so the other areas are taking over some of those functions. But it's not, like, surgically removing something or having a virus eat it away. Yeah. Yeah. So one more distinction that I wanna make before we watch the video is, what are called material specific images. So the left and right so these brain areas are really important in long term explicit memory. But the left hemisphere and the right hemisphere code different types of information. So the left hemisphere is responsible largely for encoding language based material. So things that you heard, things that you read, things that are encoded in a linguistic form, people's names, stories, and so forth. The right hemisphere would be responsible for things that are encoded more visually. So people's faces, roots, locations, objects, and so forth. This is an example from a patient who had a a tumor, in the temporal lobe in the right hemisphere, and this is a a task where they were shown a picture, they're given a minute to study it, then it's covered up, and they have to reproduce it. And this these are the forms that they would have drawn for each of these items. And though you can look at this and say, well, it sort of resembles this. I can assure you, if you were given a minute to study this and then reproduce it, you would have you would have done it all correctly. And the same patient couldn't remember people's faces, couldn't remember, like, a common route that they would take, like, in their neighborhood. So it was visually based types of materials. Whereas with the left hemisphere, it's more language based. And a really good example of this, I don't know. Have any of you watched there's been 2 now documentaries about Corey Downey, the the tragically hip, founder. Right? This is a little bit? So he had he died from a brain tumor when he was I don't know how old he was. Not old. Only 40 something. He died a couple of years ago. And he had, a brain tumor that was in his left temporal lobe. And he in the interviews that I've seen with him and then in the documentaries, he had, like, a really specific, at least at first, verbal, memory deficit. So he would give concerts when he was still able to perform and he'd have to have teleprompters, with the lyrics. He had problems with word finding. He right around the time that he became, ill, he put out an album, and it was called introduce yourself because he couldn't remember people's names. So he had a really specific verbal memory problem. And if you're interested in music at all, you might find one of those documentaries interesting. There's he's he was quite, open about, what it was like to live with the tumor and the decline and so forth. It's it's really inspiring and and interesting. Mhmm. If you're a person whose language is very viralized, with the visual spatial stuff, you can decide that. Yeah. So we'll talk a little bit about it next time. There is some variation. Almost everyone has language in the left and more visual spatial types of skills are in the right. But there's a small proportion of people, guessing I'll tell you some stats next week. I think it's about 5% who was flipped and then it's just like a mirror image pretty much. Okay. Thank you. Okay. Any other was there another question about coming? I'm just wondering if I know some of the Yeah. So it might so you're talking about things there, like, the Wisconsin card sorting test, which traditionally are thought to be more sort of frontal types of tasks because you have to change your behavior based on the feedback that you're given. But they certainly involve memory as well. So if you had an anemia, you'd struggle with that type of task. So there isn't one task. There's it's very difficult to come up with a task that just assesses one function. Because if you ask someone to name an object, well, first, you have to recognize it. That's visual. You have to come up with the word. We may probably have to activate some semantics. You have to have some memory. There's, like, there's no one task that you can use to assess, like, one individual function. So tasks will be labeled as a language task or an executive system task or visual spatial task, but it depends on the variety of things. So that's a good a very good question. Okay. Sorry. One more question. If you're working with a patient who has, like, delusional, So different people will have different opinions. My opinion would be there's no amount of correction that's gonna have that's gonna change what the person remembers. So why stress them and just go along with it? That would be my approach. Unless there's some reason, like safety, for example, where you think Unless there's some reason, like safety, for example, where you think reiterating some things might make a difference. But I think, like, like, when you look at people and maybe some of you who have some experience working, or volunteering with older people or in nursing homes, like, if you look if people are disoriented in time and space, it can be very stressful for them. So if you're constantly correcting them, it makes them more stressed and agitated. Whereas if you just kinda go along with it and be with them wherever they are, you can actually have quite a nice conversation. I can't remember. There's a video I have. It must be for next term that I use it, but someone's having a conversation with somebody who's completely disoriented and they're having this completely nonsensical conversation, but it's a lovely conversation if you don't look at the fact that it's just completely not related to anything. Anyways, anyone have anything to add based on your experiences? Yeah. Like, my OPUS and my grandpa, he was, like, I think 92 when he passed. So, honestly, for most of his life, he had, like, he was pretty, like, sharp. Like, it was only right, right, right at the very end that he declined, like, I'd say the last year or so. But it was interesting because he was in a nursing home, but he kept thinking it was like a hotel, which kind of makes sense because it's, like, their staff and he knew he was in a different place. And then also, I remember one of our last conversations with him, he kept, like, talking about New York, and he had all of these, like, really, like, vivid details. And it was very interesting, but then we were all, like my dad's, like, I don't think he's been to New York. So it was, like, probably from, like, TV or, like, something. But it was just kind of, like, we were just listening to him talk and it was, like, yeah. It was, like, interesting. Yeah. So there was this, there was this therapy that was very popular a number of decades ago called reality orientation therapy where you may attempt to, like, reorient people to, like, the reality of the world. And I don't think it worked. It caused a lot of stress, and but it was sort of seen to be something that you should do with people who were disoriented. Yeah. My, my husband, both his parents had, unfortunately, rather early onset neurological illnesses, and his mother had a a brain tumor when she was in her early sixties and had to go into a a long term care facility as she declined from that. And there was somebody in the facility who I shouldn't laugh, but it was quite amusing. She would walk around and say, I can't believe I just bought this place. I inherited so much money. This place is mine. Look at it. Look at all these rooms. And now that I'm the owner, there are going to be some major changes, and she'd start talking about all the changes that she was gonna make to this facility. I think she thought it was a hotel or something. I don't know what her issue was, but I remember, my husband was because he spent a lot of time there and he would, like, start to talk to her about what kinds of changes she was making and how she had come about this money. And she would just be, like, so involved and engaged. It was absolutely not based in reality, but did it matter? Not really. So I think unless it's real my own opinion would be unless there's some kind of safety issue involved, like, just do whatever's gonna be the most, like, meaningful and not cause the least amount of stress for the person. Okay. So what I wanna do now are there any other questions? This is a fairly, it's about a 10 minute video. So we'll watch the video, and then we'll have a bit of discussion about it, and then we'll leave the rest to, we'll talk about executive function next time. It's, yeah, it's an 8 minute video. So this is someone who had, herpes simplex It's in the UK. He was a a music professor, and there's been a whole lot written about this individual. He had a very severe form of of amnesia. Oliver Sacks wrote a story about him. It's called man without a man without a memories, the documentary. There's a long documentary. What I'm gonna show you is just an excerpt from it, and there's been lots written about this particular individual. But what I want you to think about and make notes about when you're watching the video is based on all the different types of memory we've talked about, what is affected and what is spared? Because you see examples of almost all of the memory types that we've talked about so far. Without any memories of the past nor expectations in the future. What would it mean to have no place in time? One man is consigned to live entirely within the present with terrible consequences. Clive Waring has the worst case of amnesia ever known. 20 years ago, he lost his memory, and now his wife, Deborah, is the only person he recognizes. Clive really only has less you know why I'm going? No. She's having a party at her house tomorrow. Shouldn't know. No? No. Do you know why? No. It's to do with her daughter. Yeah. She? Do you know why her daughter's having a party? No. Guess. No. I don't. She's just got married. Oh, is she? She just got married. And do you know what country she just got married in? No. Yeah. In New Zealand. Oh, I see. The sentence he is in, he will probably have forgotten the sentence before. You ask him a question, and he'll give you an answer. But while he's giving you the answer, he's already forgotten the question. That's how short it is. I'm gonna see your kids tomorrow. I'm gonna see my kids. Yeah. Your children. What are they up to now? Do you know what they're up to now? No. Guess what you think they're up to. No. I think it couldn't be. Yes. I know what they're. They haven't got another level last time we've come to. Mhmm. So is it Imagine never recognizing your own children or your own home, not even knowing who you are, not being able to hold on to the past or present for long enough to imagine the future. Not only is Clive unable to remember what he's ordered for lunch, but he can remember which flavors belong to which foods. Since Clive is unaware of anything that's just happened, he perpetually thinks that he has just come around from a lengthy period of unconsciousness. I've never seen anyone at all. I don't know no dreams do. Every time he sees Deborah, he believes it's the first time in years. He's stranded, if you like, on this tiny scrap of time. He has no past that he knows about, and he has no specific idea of the future. All he has is void behind him. I've been like death. I've never seen a human being before. Never had a dream or a thought. The brain has been totally inactive. Day and night, the same. No thoughts at all. As far as I'm concerned, night the same. No thoughts at all. As far as I'm concerned, the doctors have been totally incompetent. I've never seen a doctor the whole time. Oh, look. Come on. Before his illness, Clive was a successful conductor and musicologist. And one of the few things that have survived is Clive's ability to play the piano. It has been devastatingly sad to watch how frustrating it is for Clive, who is the man I love to suffer so horribly. I do not know of a more horrific state to be in than to have no knowledge of the whole of your life, no knowledge of any events that have ever happened to you, and no idea of anything except now. Clive's tragedy is to feel such intense human emotions without ever being able to anchor them into his memory. He's a man utterly lost in time. Okay. So it's a very dramatic example. So he had, as I mentioned, herpes simplex and encephalitis and lost on both sides, bilaterally, his hippocampus and part of his, temporal a big part of his temporal lobes. And as you can see, it's a severe, severe amnesia. But in terms of the different types of memory that we talked about, what's what's affected and what's preserved? Because there's examples of both. So I wrote down that, like, explicit memories affected because he can't remember pretty much anything from his past. And also And and is that anterior grade or retrograde or both? Oh, well, both. Because there would be retrograde amnesia because he can't remember his past and then also interior grade because he can't put down new memories. Right. So his wife tells him a story about, like, the party with his sister and lots of other examples, and he cannot hold that for, like, even a few seconds. And his past in terms of, anterior or retrograde explicit memory is It's gone. It's gone. Can't remember his children, can't remember any details about his past and so forth. Okay? And then I also said that he does still have implicit memories, especially with, like, playing the piano. It's like that sort of skilled task learning is preserved. And I was also very curious if he could, like, learn a new piece of music, like, you know, like adding, like, a new task, kind of like, like, because he still has the skill to, like, play. Like, if he could, like, learn it, like, not sight read, but, like, actually learn something if that makes sense that way. So in terms of music, he's playing the piano. He appears to be reading the music. So he's remembering how the notes correspond to what he has to do on the keyboard. So my my guess would be that he could, like, sight read a piece of music and probably remember it. I don't know. Can anybody? What I'm finding interesting about the the sight reading is, I mean, if you're playing the piano especially and reading that kind of music, you're reading a couple bars ahead. I know. So there's some amount of of memory in there somehow. Yeah. It's working memory because it's able to, like, anticipate. Yeah. And yeah. So great examples of preserved, to some extent, working memory and in that in the implicit skill based context. There were some other really good examples of preserved implicit memories. Did can you think of what those were? Yeah. He used, like, the knife and fork correctly. He used the knife and fork correctly. When they went into the restaurant, he held the door open for his wife. So that's like a sort of, you know, social skill that somehow got cemented in his brain. There was another example too of preserved, impulsively. I just had a question. So, like, it seemed like a lot of his semantic memory is intact because he was talking about, like, dreams and his brain and death and all of these concepts that he obviously had he was talking about them appropriately. But then when he looked at the chicken, like, he couldn't identify it. And so I wondered if there's, like, a difference between, like, visually stimulated semantic memory versus, like, something kind of thought of internally. Like I know. Because so his episodic memories were wiped out. Semantic, though, was kind of patchy because the issue with the chicken, he had difficulties with it. The cooked salad, like, the spinach behind it. And yet some examples of when he when his wife was relaying the story about the party, and then he just kinda guessed, he said, oh, is it for a birthday? So he knew that birthdays would go with parties. And then when she said that my son had a PhD, he said, oh my goodness. That's good. So he knew that the p a PhD was something that, you know, you should be, like, viewed positively. So I don't know if that's, like, a verbal visual. I don't know what that relates to. But semantic memories were, like, definitely more intact than episodic, but kind of hit and miss. Yeah. What is that? Like, I think it was wife fault. Like Yeah. What do you think about that? Anyone except for his wife. So is that more like an emotional thing? I think so. Yep. So I think his wife, for whatever reason, was coded in such a strongly emotional way that it's it involved a different set of circuits that her face and her voice and her presence, you know, he he had no difficulty remembering. Oh, I know what the other example of spared implicit memory was. It was the dance steps, like, when she came in. He could do those, fine. Is there another hand up? Yeah. I just wanna say, like, the romantic kind of aspect of his personality scene there with, like, the dancing and the arm around her and, like, the holding of the door. Yeah. Maybe that's, like And the affections and, like, all of those things were preserved. To the kissing in the front. Yeah. Yeah. So it's it's a memory, but it's encoded in a very different way than the explicit memories. And what about so we've talked about anteriograde and retrograde. We've talked about episodic and emotional and semantic. What about the left right distinction, like visual versus verbal? Any differences there, or was it sort of both globally affected? When she was, like, breathing off the venue or, like, options, Right. So again, when she was reading it, that was like a sort of probably a more semantic type of and you understood language. So that's semantic memory too. So I don't know if there was more of a his semantic memory seemed to be I'm just I don't know exactly what happened, but I wonder if his semantic memory memories were is semantic memories better for verbal overall than visual? I think so. Yeah. So maybe the semantic circuitry on the right was more effective than on the left, but episodic circuitry was bilateral. I don't know. I also think in regards to semantic memory, it was interesting that he did seem to have, like, a lot of knowledge, I guess, of, like, dreams or, like, coming out of unconsciousness or, like, even medicine and doctors and all of these things? Because if you think about, like, the state he exists in, I think your brain I mean, your brain, one of the kind of amazing things about it is it's always gonna, like, try to, like, quote unquote, heal itself or, like, rationalize what's happening. Mhmm. So even for something that's so profound, it's like you can tell his mind is still trying to make sense of it. And that explanation of, like, oh, I just, like, came out of a coma or a dream. Like, that kind of is the most, like, sensible explanation of a certain sense. I'm sure something lingers on a lot and so it stays. Yeah. That's a great observation. And you clearly knew, like, I can't remember what his comment was, but there was a comment about doctors and the sibling. Yeah. Yeah. I'm kind of like a book of doctors. It seemed to me like it was kind of maybe Yeah. And not to be overly sentimental here, but I think this those observations make, a very important point about your role as clinicians because you can be working with people who are very severe severely impaired, and yet how you behave with them and how you act with them and the kindness that you showed is being coded in their brain somewhere even if they don't remember you when you come back again. So I think it really, just because people have severe cognitive behavioral issues, it doesn't mean that what you do doesn't matter. It matters a lot. And I think, yeah, it's very important. So, again, I'll just say it's a very severe case, but it it illustrates nicely how memory can break down and the different brain areas play different roles. So, great discussion. Thank you very much. Let's leave it at that for you today. And next time, we'll talk about, key remaining functions. It seems really satisfying. It was. And it was, like, tactile tactile. Yeah. Yes.