 episode of In the Studio. And my guest today is Professor Sharon Wrangana. He is the director of the UC Davis program of Memory and Plasticity, MAP, within the Center of Neuroscience, and he's also a professor in the Department of Psychology. Welcome. Thank you. Thank you for having me, Lynn. Thank you for coming. And our topic today is going to be memory and the secret world of memory. And memory is who we are. And as you may know, the French 19th century novelist, Marcel Proust, discovered the power of memory when he tasted his famous cookie. Yes. And after that he published a long series of psychological novels, very long novels. So here we are. Well, Professor Wrangana is a prominent researcher in the vast and complex field of the brain. And so when I was preparing for this interview, I began to read about what he does and I was spellbound. And I quote, our research involves the use of functional neuroimaging, scalp and intracranial electroencelephalography to study the neural basis of human memory and executive control, et cetera, et cetera, et cetera. I hope you're going to make it a little more easy for us. Yes, definitely. I should probably rewrite that. Oh, it sounds wonderful. Very mysterious. Yeah. Very secret. Very secret. Yes. So what would you say are some of the most interesting advances in the study of memory at the moment? Remember, we are lay people here. Oh no, that's fine. That's fine. I think probably the biggest advance is, it's a very exciting time to be studying memory because we have new technologies that allow us to get in the brain and we have methods to kind of identify what people are remembering at a given time. And so there's been this convergence of studies in humans and studies from animals that are allowing us to break down what a memory even is, right? Yes. Because you can remember something in terms of being able to see someone's face and be like, I've seen this person before. Or you can remember something in terms of, say, going back to, you know, Bruce Cookie kind of thing, where you have something that just takes you back to a particular time and place. And it's just so powerful, isn't it? And it's vivid and you re-experience all this stuff. It's like you get the sensory information, the sights and the sounds, you know, the smells especially. Smell. Yes. Yes. And so that's all, if you think about it, that so many different parts of the brain that are processing so many different kinds of information, that we're now just starting to figure out, okay, how does the brain file all of those different kinds of information and how are they linked together? And so we have techniques, some of which are a little bit simpler, but some of them are also more complex using things like machine learning. Yes. Where we can image people's brain activity, say, while they're watching a movie. Yes. And then we can identify while people are just remembering the movie. We can say, ah, this is essentially what's happening in the brain as people call up that memory. And what's amazing is, is that you can find brain areas that, you know, across, you know, let's say if you remember this interview later, it's going to be probably a 15 minute interview. Yes. And if somebody asks you what happened, it might take you two or three minutes to recall what happened. All more. Will it help if I show one of the pictures? Absolutely. And maybe you can expand a little bit about where memory is functioning, or at least that's what I would like to do. Yes, absolutely. Absolutely. So if you can show this, this is a nice brain. It's schematic, of course. Yes. Yes. Well, actually, this is a real brain, but what we did with it, it is a real brain, but what we do is we can use software to say, because if you imagine the brain's like, imagine it's like a football that was deflated and all crinkled up. And so this is literally, we call it brain inflation, where we imagine what would the brain look like if we could puff it up with air and make it all look, you know, completely flat. And this is puffed up. This is puffed up. And so you're looking at the middle of the brain here. And so what you can see is that there's areas both, one area is kind of deep in the middle of the temporal lobe called the hippocampus. Yes. And there's other areas that you can see, the bright areas kind of towards the back middle. And that's, those are areas in the parietal lobes. And so these areas in the parietal lobes are very interesting, because as I was saying before, if you watch a movie or you do this interview, what you'll find is that you tend to break it up into little segments. Yes. You might go, okay, we start off with the introduction. And now we're doing the photo tour and so forth, right? Yes. And so you can actually see these patterns of the brain saying, Hey, here's event number one, here's event number two, here's event number three. And when people recall it, you catalog them from your brain. That's right. And we sort of, it's called, we segment them too. So even though if you think about our life, it's a continuous timeline, right? But when you remember things, you don't remember it like that. You sort of break it up into things that happen at particular chunks of time and space. Yes. But this is very interesting. Let's show another image that perhaps, oh, this is you. It's a nice picture with a very nice hat there. Thank you. Well, so this is, this is usually there's very smart people in my lab who do that kind of work with me. Yes. But this is just a picture of me doing it. We're doing what's called electroencephalography, which you also read about on the website. Except that you pronounce it properly. You did fine. You did fine. Yeah. And so electroencephalography is a way to measure electrical activity in the brain because it. And map it. And map it. Yeah. It's not that great for figuring out exactly where it's coming from, but it gives you information in the millisecond range in real time. Because if you think about it in just, let's say, one tenth of a second, your brain is volleying back all of these different kinds of signals. And what's really interesting is, you know, if you see a performance and everyone starts clapping, you notice within about a second or so, everybody's clapping in sync, right? You know, just here, you know, it's like everybody gets into a rhythm. Oh, that's very interesting. And that's how people naturally interact with each other. And so you can see these kinds of rhythms and brain activity, too, if you record electrical brain activity. And so we call those oscillations, but they're basically rhythms that are showing how brain regions are interacting with each other. And so this method is really good for getting at that because one of the things we found that I'll show you a little later is that you can actually try to stimulate those brain rhythms and improve memory. Yes. Well, this leads me to my next question. But before I do that, you mentioned tools, better tools. Can you give me an example of one being the one we just solved, right? The encephalo... Electroencephalography. Yes, yes. And that is proving very effective at the moment. Yes, yes. Electroencephalography, magnetic resonance imaging, which was the first thing that I showed. In animal research, one of the... I should add that there's a big movement towards integrating these techniques with advances in machine learning and computational modeling where the idea is to say, you know, the brain's a complicated place. We've got all of these different things happening at a very fine timescale. And so a computer model can help make sense of all that information and sort of act as an interpreter between what we think people are remembering and what we're seeing in the brain. And the Center for Neuroscience is the perfect place to be because of all the interdisciplinary contribution that it receives so many team members and experts in various aspects of this. It's probably the only way to crack some of the things that you're studying. So that's very good. Let's go to the next image. And this is another... Well, actually, we must point out this is actually a gif, but we aren't able to rotate it at this moment. So it's okay because we can see all the nice colors. Yeah, people might get motion sickness anyway. Yes, that's right. That's one risk. So what type of... What are you showing here? So this is an example of what's called diffusion tensor imaging. Yes. And so this is again a real brain, but we've done some funny stuff with it. So what we did is we use this technique to understand what the white matter looks like in the brain, right? So normally people talk about the brain as if this kind of information is done here and this thing is done here, but the brain is a connected network. So just like you have social networks where you interact with people, the brain is like this too. You have brain regions that are talking to each other, and the white matter is like the telephone lines that are connecting different brain areas together. And so one of the things that we're starting to realize is the integrity of that white matter is very important. And so you can be somebody who doesn't even have Alzheimer's disease, you can be somebody who just has diabetes, let's say, and they have tiny little events, probably tiny strokes that affect the integrity of that white matter. And so imagine if you start snipping the telephone lines, brain areas can't talk to each other, and they can't produce those kind of rhythms that I was telling you about before. Is that curable? You don't want it to happen to you. We don't know how reversible it is, but most likely once you lose those connections, you probably don't get them back. I should say there is some evidence that when you learn something new that you can get changes in the white matter, and it's not clear whether that's forming new pathways or if it's just something that's a strengthening of an existing pathway. So I think it's still unclear. It's still unclear. And so do you think that the healthy aging process affects the way memory works or at least how powerful this memory depends from individual to individual, of course. But what would you say is a healthy aging process of memory? You really nailed it, that it varies a lot from individual to individual. So if we take a group of UC Davis undergraduates and compare them to a group of UC Davis graduates who are in their 60s, the variability amongst those people in their 60s is much, much higher. And so part of the reason, we're still trying to understand what makes people's memory different from each other. And so in fact, the white matter imaging that I was showing you is part of our one of our projects to try to understand why and how people vary. In general, as people get older, if you're perfectly healthy, you'll still generally say my memory is not as good as it used to be. Of course, yes. But usually what you find is is that people often, it's kind of like, you know, my office gets messier and messier as I get more and more jobs and I have trouble finding things. So there are certain sensual factors that influence your memory because if you had only one piece of paper on your desk, you would find it no problem. That's right. Yes. Yeah. And of course, there are also changes in the brain that happen even over the course of healthy aging. But those changes can be very small or very large depending on the person. On the person, yeah. And their lifestyle. And the lifestyle, of course. And also, there was recently I read that one experiment they're trying to do, and I'm sorry I can't remember the source, but that's okay. That's normal. Is it normal? Good. I'm glad. That for sufferers of PTSD. Oh, yeah. There is a new approach to modify or manipulate, if you like, the memories. Have you, of course, you've heard about it and you're probably studying it too. Yes, yeah. We're not studying PTSD in our lives. Per se. Per se. But the broader thing that you're talking about is, again, another one of the breakthroughs that people have had in our field recently. So it used to be, and many people still think this, that when you recall an event, it's like you push play on the memory. That's right. Like a little button there. Yeah. That's right. Yeah. That's exactly right. And what we now know is, is that when you push that button, you're both pushing play and record at the same time. Oh, how very interesting. Yes. Explain. So basically, when you reactivate a memory for a past event, you go back and you remember your 16th birthday or something like that. It's like you've opened up this little box where your memory is. Yeah. And now what can happen is, is that you can strengthen that memory and just increase the amount of stuff in that box. You could also, though, end up, somebody could be talking to you and the things that they're saying could be incorporated into that memory, in which case it becomes a little distorted. You could also become distracted, and that could potentially, some people argue, will make it less accessible in the future. So when you open up a memory, all sorts of things happen. Well, that is very interesting because it makes me think of testimonies. That's right. In the court, you know, how reliable are they? Yes. You know, and before DNA or whatever, you know, people were accused on the basis of someone's testimony. So would you say that there is a way to improve the understanding of how this works and how we enrich or, you know, deprive the memory? Yes, absolutely. So one of the things with eyewitness testimony, for instance, is that people will often recall something, but they can get, they're vulnerable to suggestions. And prejudices as well. As well. That's right. That's right. And sometimes, what happens is when you remember something, it's like your brain's being a little detective and it's trying to put together the clues and give you a little story about what happened, right? Yes. And sometimes, like you said, those prejudices can come into play, but also that opening of the box that I talked about. I like the idea of the box, yes. Yeah. So there are many cases where well-intentioned law enforcement, for instance, would ask people questions and they would feed them the answers, you know, and they would say, do you remember putting the gun in the cabinet or something? Yes. Yes. And what happens is, is that people, especially when they're stressed out and if they've undergone trauma, for instance, it can be even more likely that they could start to get confused between what people told them and what actually happened. And they open up the box and they put in this other stuff in it. I'm afraid our time is up. Oh no. 15 minutes go so fast when it's interesting and we've only scratched a very surface. So I hope we'll be able to have you back. I would love to. And talk a little more about special areas. But at the moment, thank you so much, Professor Ranganar, for taking the time. It's all so fascinating. And thank you all for watching. If you like this episode, you can watch it again by streaming it on our website at DCT, davismedia.org and check out some of our other programs. We have a lot of interesting people and topics for you. And from all of us here, thank you and see you next time. And thank you, Professor Ranganar. Thank you, Lynn, for having me. We look forward to coming back. Thank you.