All right. Memory is a very big topic, and I've, I know we've been sort of bouncing around a little bit. And I've been showing you some tidbits of some really interesting things about memory. it is something that literally, we could of had a, a whole MOOC on memory itself. so you know, it's hard for me sometimes to decide what to hit and what not to hit. And in this case, I thought it was really important that we end this by talking about the relation between memory and the brain. So the next two lectures will focus on that. we'll get into some issues of the amnesias, especially in this lecture. but more globally I'm hoping that by the end of these next two lectures. You have a real sense of why memory is so critical to us and who we are. so that's the plan for the next two lectures. Let's get going. Alright, Week 5, Lecture 7, Memory and the Brain. And there's our little friend the brain over there, nice and pink, looking good, looking healthy. Just like our brains, alright. I want to start with this, we're going to talk about Amnesia. So situations where memory stops working properly. And there are various kinds of amnesia, so I want to introduce you to a few stories. And a few people, and, a little bit about how we know these amnesias occur. So we're going to start with what's called Retrograde Amnesia. I sometimes call it Soap Opera amnesia, because they love playing with this notion on soap operas. The idea that somebody could appear somewhere. And suddenly have no memory of who they are, what they did, or anything that happened to them before that point. And of course if it's a soap opera, they're married and have four kids but they don't know that. And then they find some new person and marry that person and have another four kids and they reunite, that's fun. Now, in real life, this kind of amnesia, well, it sort of happen and it doesn't happen. There is one situation where it does happen pretty regularly, but it's not that exotic. So, if you ever get concussed really hard, so you hit your head against something and and suffer a concussion. It's very common that people who have a concussion will have some amount of memory loss for past experiences. But it's usually like if this is the point of the concussion there's some area of time before that point that when the person wakes up, they can't remember. And sometimes this can extend pretty far into the past. So they may have trouble remembering who they were. And maybe if they got married, they might not recognize their wife or something like that. often that amnesia reflects to some extent damage to the brain or swelling in the brain. And so often over time as they person, as the brain starts to get back to it's normal self, that memory loss disappears. And it starts from the furthest memories that the person couldn't remember, and works it's way in. So that usually a person with that situation will get to a point where they remember just about everything from their past. But they may not remember the last half an hour or so before the accident, orr 10 minutes or 15 minutes, etcetera. There's a period of time that they never seem to remember. but other than that, they tend to recover it. So it's not the dramatic soap opera memory, it's usually a game because of some sort of concussion. And it starts out in the soap opera way, but it shows this pattern of usually relatively quickly returning, other than that little bit. But there are some cases, and I have one highlighted here, that seem more like the soap opera one. So in Toronto, in fact, just this, past summer, well, fall, I guess. we had this woman who showed up with amnesia. She literally, her name was Linda, but we didn't really know that at the time. she had just literally shown up in a homeless shelter and she had no memory. Could not tell us anything about herself. all she could remember was this intersection in Halifax, a city in the east of Canada. And so, she could describe this intersection a little bit, and that made people think, well, maybe she's from Halifax, but it turns out she wasn't from Halifax. She was actually from America, and she was a Schizophrenic. So she was living in a halfway house in America. Some sort of big stressful event happened and she seems to just lost all memory of who she was. And somehow she rode into Canada on a bus with an expired US passport, and ended up in Toronto, and had no idea. And it was a great mystery for everyone to try to figure out. Who this woman was, so that does happen on an occasion. And I'll have a link to this story at the end if you want to read more about it. But really this isn't that, common. not as common as soap operas would, at least, would have you believe. What is sort of more common, and maybe more interesting is something called Anterograde Amnesia. Now, I don't want to say it's more common. It's certainly not more common than the concussion kind of retrograde and that happens quite a bit. But that real extreme kind where person is lost their memory totally and it's not coming back, that's uncommon. Anterograde, this tends to only happen when the hippocampus, the structure deep inside the brain that we talked about earlier. When this part of the brain gets damaged in a very severe way. In fact, often the, the cases that we have of this kind of amnesia are caused by surgery. literally surgery performed on the brain and the famous, perhaps most famous, example is a patient named HM, or Henry M. Henry had severe epilepsy. When you have severe epilepsy, a signal starts on one side of the brain. I think we visited this with the split brain. It goes to the other side, comes back. Goes back and forth, and back and forth, and back and forth. And gathers in strength, becomes stronger and stronger and stronger. Eventually, the person suffers essentially a short circuit of the brain. The whole brain wires up, the person passes out. And of course, they show all the convulsions, because their motor cortex is being stimulated, which is causing their body to move. Henry M, was a patient who had those sorts of seizures several times a day. Sometimes up to ten times a day. So, he didn't want to leave the house, because he wa, he lived in constant fear that one of these seizures would hit at any time. He was not enjoying his life, and he was willing to undergo a very extreme procedure. And specifically, because his epilepsy seemed to emanate from the hippocampal region. He underwent a surgery where the hippocampi on both sides of his brain. So, bilateral removal of the hippocampus. both sides of the brain, that was removed. Nobody knew exactly what that would do, what would happen. and, but of course, Henry M recovered. At first he seemed okay, in fact when you speak with Henry, he can hold a conversation, he seems largely fine, largely normal. But something weird happens if you leave the room, specifically if you leave the room and then come back, Henry has no memory of ever having met you. And in fact as people started to experiment with his memory a lot more. What they realize is that this hippocampus seems critical with respect to us laying down new memories. So when we're experiencing the world, we're seeing things. Those experiences, somehow, have to get brought from our working memory, which is where we would first have them, into our long-term memory. And it seems like that's what the hippocampus does. And without that structure in place, a person can still experience things. But once those things are over, they don't remember what they experienced. So Henry M could remember his past life fine. Anything that he experienced when his hippocampi were intact. That all got stored in memory, and he could still access memory. He could still know about his childhood and things that happened. But from the day he had his hippocampi removed, he could not remember things from that day forward. He couldn't consciously remember them at any rate, kind of fascinating. If you watch the movie Momento, it depicts a similar situation. a person in a much more, you know, interesting dramatic context. But, I, I would suggest you check out Memento, if you can. It's, it's a movie that you should watch, and it messes with your own memory. So it's a good one to get you thinking about memory. But the character in Memento is a character like Henry M. he can remember something as long as he keeps it in mind. But his moment his mind turns to something else, whatever he was thinking about before, gone, very dramatic. So if we kind of think about retrograde versus anteriograde, for retrograde we have some point at which damage happens. So it says Lesion here, but it could be just a pump, a bump on the head or something like that. And then the patient has poor memory right before, for events that happened before that event. And then as you go back in time, you tend to get to a point where memory is fine. But there's this graded, as we call it, memory loss. but then severe memory loss for events just before the lesion. And again, over time, usually this whole thing shifts this way. You still have poor memory for what happened just before the event. But usually this memory loss starts to recede, over time. For Anteriograde amnesia, like HM, he has perfectly fine memory for everything that happened before his surgery. But from that point forward his ability to lay down new memories is in, is extremely su impaired. Okay, different patients are impaired to different levels. Henry M is actually quite impaired. So, re, real difference, is it memory for going backwards in time or memory for going forward? There's another extreme case that you really have to see some videos, and, and look at to really have appreciation of your own memory. Clive Wearing was a music composer and, and a very intelligent, important, powerful man, very successful man. but then, he suffered something called Herpes Encephalitis. Now herpes is very common, but sometimes it can lead to an infection of the brain. and in his case he had late to extremely high fever and in fact a lot of his brain areas were damaged. Including hippocampo area, but also the frontal areas. and that made it hard for him to remember anything. So he's got a really bad combination of not being able to remember events from the past. the retrograde, but also not being able to lay down new memories, anterior grade. So, Clive is living eternally in the present, hence the title, Forever Today. Now, its a really touching and interesting story when you learn more about Clive's, so theres a book called Forever Today. this is his wife Deborah, and it seems that, you know, what Clive paints a picture of is what would it be like to not have a memory. To only live in the moment all the time, and he keeps a journal. And what you see is, he had written, now I am totally perfectly awake for the first time. he would write than in his journal, but then the next moment he would say no, no now I am, now I am. I don't even know what this is, seriously or something perfectly awake for the first time, and he's crossed. He's went back or no, no before I was just almost awake, and, and it wasn't for the first time. He keeps writing this over and over, why does he keep writing this kind of thing. Because, he just feels like every moment of the day feels like that moment when you just wake up. And you realize what's around you. And he's constantly waking up, waking up, waking up. It's like the past keeps disappearing. Now you see you know, interesting there's food arrived, a delicious piece of chocolate. so he's able, you know, in the moment he can keep that in mind. His working memory seems okay, he just can't retrieve anything from the past, or lay anything down for the future. first patient's game ends, I am really awake but then these are the kind of nice things. Hello darling, I love you. He will mention Deborah and, and he still has love for Deborah. In fact one of the both, most creepy and beautiful scenes from some of the videos you will see. Is that when Deborah leaves him, now maybe just to go to the kitchen, maybe just to go to the store around the corner. But when she leaves and then comes back, he has the sense that she's been gone for a long, long time. So he reacts to her as you or I would react to a spouse who'd been gone on a trip for two weeks, and then comes back. And you say, aww welcome home, I love to see you, welcome back, and you give a big hug. You know, those sorts of hugs, those sorts of greetings. He does that every time he sees her. Which is sweet, but it's also a little over the top, it's a little much. And it says a lot about what's happening in his mind. and so when you watch these videos of Clive. What you get a real strong image of, is, wow, memory is what keeps us, whole. It what, it's what gives our existence continuity. So, we think of ourselves as here, but we also think here relative to where we were, and where we plan on being. And so we're a point on a continuum for most of us. But if you're just a point, if that's all you have is right now, right here, it's a very different kind of existence and not necessarily a very cool existence. so, what you really have to do is see this. I, I just have one link here, but in fact it's a link to many videos. There's a channel on YouTube that has videos of Clive and Henry. So you can see them in action. You can hear, learn more about them one of the things I want you to know for Clive for the next lecture. Is notice that although he's got no memory for a lot of things, when he sits down in front of a piano, he can still play the piano beautifully. Something about that ability has not been lost. We'll be talking about that next lecture. So, so notice that, if you want to see that mystery Toronto woman click here, you'll find a little bit more. And I just have a link here to Amazon I think for the, yeah, for the Forever Today book. So if you actually are interested in, in the book check it out, are you? So from here, we're going to go on and we're going to talk more about amnesia. But I'm going to sneak in that procedural memory, like the piano playing. I want to come back to that because I want to try to tie a bit of a bow on all we've been talking about. Even though I've kind of been here and there, I'm going to try to bring it all together by talking about, the things that amnesic patients can still do. And what that tells us about memory. Okay, so cool, I will see you in Lecture 8. Have a great day. Bye bye.
