WEBVTT - Erasing Memories with Light 0:00:00.160 --> 0:00:07.240 Brought to you by Toyota. Let's Go Places. Welcome to 0:00:07.400 --> 0:00:14.000 Forward Thinking, Be There and Wealth into Horrid Thinking. The 0:00:14.040 --> 0:00:16.640 podcast it looks at the future and says, I remember 0:00:16.680 --> 0:00:24.119 when rock was young. I'm Jonathan Strickland and I'm Joe McCormick. So, um, memory. 0:00:24.720 --> 0:00:27.000 I wanted to talk about memory today. Specifically, I wanted 0:00:27.000 --> 0:00:29.320 to talk about memory because it's one of my favorite 0:00:29.800 --> 0:00:32.559 things that pops up in science fiction, the idea of 0:00:32.600 --> 0:00:35.040 messing with memory. I thought you were going to say, 0:00:35.040 --> 0:00:37.239 it's one of my favorite things that pops up in 0:00:37.320 --> 0:00:41.560 my brain. It can be I don't know, are you guys. 0:00:41.640 --> 0:00:44.599 Do you guys ever have that issue where you are 0:00:44.840 --> 0:00:49.000 you are feeling really relaxed and content and you're you're 0:00:49.040 --> 0:00:51.479 feeling like things are really going well, and then your 0:00:51.479 --> 0:00:54.680 brain this whole this can't happen, and so pulls up 0:00:54.720 --> 0:00:57.080 a terrible memory of something you did where you made 0:00:57.080 --> 0:01:00.560 a complete jackass of yourself and then replays it. Yeah, 0:01:00.680 --> 0:01:03.120 brains are jerks. It wouldn't be awesome to get rid 0:01:03.120 --> 0:01:05.200 of that memory so that we would no longer have 0:01:05.240 --> 0:01:07.360 that and when we're happy and content, we can just 0:01:07.560 --> 0:01:10.600 basque in the moment. Oh absolutely, and according to science fiction, 0:01:10.760 --> 0:01:15.000 this is easy peasy all the time, right continually. Wait, 0:01:15.000 --> 0:01:18.520 are we talking about about removing bad memories? Are adding 0:01:18.520 --> 0:01:24.440 good memories? Either one? Okay, so you have like inception, Sure, 0:01:25.160 --> 0:01:27.600 that's kind of that's more like than the dream world. 0:01:27.640 --> 0:01:30.880 But that's related to memory, all right, fair enough, that 0:01:30.920 --> 0:01:34.280 can definitely involve Yeah, you're right that that is dreams. Yeah, 0:01:34.360 --> 0:01:37.600 that's getting mixed up there. But but total recall, Total recall. 0:01:37.680 --> 0:01:40.960 Now that's a classic film, and we're talking about the 0:01:41.880 --> 0:01:50.640 nineteen is the amazing, amazing science fiction film. I did 0:01:50.680 --> 0:01:53.280 not see the more recent one, but it looked slick 0:01:53.400 --> 0:01:56.480 and boring. I saw the original one in the theater. 0:01:56.720 --> 0:01:59.000 I remember all the stories coming out about how the 0:01:59.040 --> 0:02:03.400 body count in that movie was astronomically high. Yeah, it's 0:02:03.400 --> 0:02:06.480 incredibly violent. Yeah, and it uh, of course has one 0:02:06.560 --> 0:02:10.040 of the best tour de force performances by Mr Schwarzenegger. 0:02:10.360 --> 0:02:13.560 You mean on the commentary track where he describes everything 0:02:13.600 --> 0:02:16.880 that's happening on the screen as it happens. That that also, 0:02:17.360 --> 0:02:20.520 I was thinking specifically in the context of the film itself, 0:02:20.560 --> 0:02:24.440 but it does in fact spill over into the meadow 0:02:24.520 --> 0:02:29.960 world around the film. Thank you, Thank you, Joe. Uh, 0:02:30.000 --> 0:02:31.840 that was a direct quote. We want to make sure 0:02:31.880 --> 0:02:36.000 we reference that, but yeah, total recall. Of course, the 0:02:36.000 --> 0:02:38.360 the premise of the movie is that you have a 0:02:38.440 --> 0:02:42.519 character who he's kind of like going on a vacation, 0:02:42.760 --> 0:02:44.720 but in this in this case, he's having a vacation 0:02:44.760 --> 0:02:47.800 implanted in his mind. Yeah. The service they sell is 0:02:47.919 --> 0:02:50.000 they say, well, you know, it's cheaper than going on 0:02:50.000 --> 0:02:53.320 an actual vacation. We'll just give you memories that make 0:02:53.400 --> 0:02:55.880 you feel like you had a vacation. And in this case, 0:02:55.919 --> 0:02:58.680 the memories were supposed to make him feel as if 0:02:58.720 --> 0:03:03.080 he were some sort of super spy who had traveled 0:03:03.080 --> 0:03:07.079 to Mars and been part of this major operation where 0:03:07.200 --> 0:03:09.040 uh it was you know, he was kind of the 0:03:09.080 --> 0:03:12.799 difference between life and death for the planet. But within 0:03:12.840 --> 0:03:14.720 the context of the film, it also opens up the 0:03:14.720 --> 0:03:18.720 possibility that he really is, in fact, this superspy and 0:03:18.919 --> 0:03:22.119 he just believes he's a normal guy because those memories 0:03:22.160 --> 0:03:26.040 have been implanted. Yeah, So either way, whether you go 0:03:26.240 --> 0:03:28.880 with the story that he's a normal guy but believes 0:03:28.880 --> 0:03:30.520 he's a spy and everything else is playing out in 0:03:30.520 --> 0:03:34.120 his mind, or he really is a spy but he 0:03:34.120 --> 0:03:36.520 thought he was a normal dude because his memories had 0:03:36.520 --> 0:03:39.760 been supplanted by these these fake ones. We're talking about 0:03:39.800 --> 0:03:42.960 messing with memory. Uh, And this is not the only 0:03:43.000 --> 0:03:46.000 time we see this pop up in science fiction, certainly not. 0:03:46.040 --> 0:03:48.840 There was also Strange Days. Strange Days Out Where is 0:03:48.880 --> 0:03:52.320 one of my favorite, incredibly disturbing films. I remember seeing 0:03:52.360 --> 0:03:56.080 that that movie and being very interested in the idea 0:03:56.240 --> 0:03:58.040 of this is this is just sort of a thing 0:03:58.120 --> 0:04:01.640 that is uh, sort of the often in that particular movie. 0:04:01.680 --> 0:04:05.440 But they have the super conducting quantum interference device or SQUID, 0:04:06.360 --> 0:04:09.520 and this allows you to record memories. So a person 0:04:09.560 --> 0:04:11.960 who has one of these devices can record memories that 0:04:12.000 --> 0:04:15.680 they are experiencing and then can essentially export those memories. 0:04:15.720 --> 0:04:18.080 I mean they hold onto them themselves too, it's more 0:04:18.120 --> 0:04:20.440 like a copy. They can export a copy of those 0:04:20.480 --> 0:04:23.520 memories to someone else who can then experience those memories. 0:04:24.000 --> 0:04:26.280 In the context of the movie, it all ends up 0:04:26.480 --> 0:04:30.440 involving a robbery gone wrong, a bank has gone wrong, 0:04:30.480 --> 0:04:34.800 and then nefarious things unfold because of it. But yeah, 0:04:34.839 --> 0:04:38.160 there's another one where we're talking about letting someone experience 0:04:38.160 --> 0:04:41.560 the memory that they themselves have not actually formed personally 0:04:41.880 --> 0:04:45.120 based on their own experience. There is eternal sunshine in 0:04:45.200 --> 0:04:47.400 the Spotless Mind. I remember I went and saw this 0:04:47.440 --> 0:04:50.400 in the theater knowing nothing about it, Like I hadn't 0:04:50.400 --> 0:04:53.360 even seen a trailer, and it was a great experience 0:04:53.440 --> 0:04:55.960 because I didn't know what was going to happen in 0:04:55.960 --> 0:04:58.520 the movie. It didn't have a clue, and when the 0:04:58.600 --> 0:05:01.840 plot developed, spoil or alert that. It does eventually turn 0:05:01.920 --> 0:05:04.880 into a situation where there's a service in the movie 0:05:04.920 --> 0:05:07.880 that sells you the option of erasing memories, such as 0:05:07.880 --> 0:05:12.640 like the memory of an ex boyfriend or girlfriend right right, 0:05:12.720 --> 0:05:14.520 someone who you're no longer with, and you just want 0:05:14.560 --> 0:05:16.720 to wipe that from your brain entirely because it's just 0:05:16.800 --> 0:05:19.479 too painful, right like, like even the good memories, you 0:05:19.480 --> 0:05:20.839 want to get rid of them because now that you 0:05:20.880 --> 0:05:24.280 no longer have that relationship, it's just a it's painful 0:05:24.320 --> 0:05:27.840 to even recollect. So that becomes the central premise of 0:05:27.880 --> 0:05:29.640 that film. And I mean, or at least that's the 0:05:30.080 --> 0:05:32.960 kind of the instigator for things that happened within the movie. Yeah, 0:05:33.000 --> 0:05:35.040 I'd say the central premise really is more of a 0:05:35.160 --> 0:05:37.880 question of, you know, should we do this? Do we 0:05:37.960 --> 0:05:40.120 really want to forget the things that we think we 0:05:40.200 --> 0:05:43.080 want to forget, and wouldn't we miss those memories if 0:05:43.600 --> 0:05:46.520 once we get to that situation, wouldn't we want them back? 0:05:46.920 --> 0:05:51.240 And then, of course, another another central film in the 0:05:51.279 --> 0:05:54.680 concept of memory manipulation every bit is deep and loving 0:05:54.839 --> 0:05:59.720 is Men in Black with the neuralizer, the little the 0:05:59.760 --> 0:06:02.640 little a flash bang, a little flashy device makes you 0:06:02.720 --> 0:06:07.240 forget the last, you know, whatever, the last, however convenient 0:06:07.279 --> 0:06:10.200 it is to the plot many minutes that have just passed, 0:06:10.600 --> 0:06:13.480 so that the Men in Black can can convince everyone 0:06:13.600 --> 0:06:16.680 that it was just you know, swamp gas or an 0:06:16.720 --> 0:06:20.239 electrical disturbance rather than aliens running amuck. Yeah, and actually 0:06:20.360 --> 0:06:23.919 less you forget. The best version of this plot device 0:06:23.960 --> 0:06:27.159 in films is in the Golden Globus film Superman. For 0:06:28.160 --> 0:06:32.159 where Superman, how is it possible that, no matter what 0:06:32.279 --> 0:06:35.440 the topic is, you somehow find a way of wrapping 0:06:35.440 --> 0:06:38.520 this back to Superman for a quest for peace? Well, 0:06:38.560 --> 0:06:42.760 you know, you've got to find peace somehow. Somebody's got 0:06:42.760 --> 0:06:44.520 to do it. It's not gonna be the President, it's 0:06:44.520 --> 0:06:47.000 not going to be the Russian. It's got to be Superman. 0:06:47.080 --> 0:06:49.800 Produce your explanation and pray, make it improbable. Well, if 0:06:49.880 --> 0:06:53.200 you recall from the film, there's a scene where Superman 0:06:53.279 --> 0:06:56.440 basically reveals his identity to Lois Lane and then he 0:06:56.480 --> 0:07:00.880 wipes her memory, which it seems a abusive That also 0:07:00.920 --> 0:07:06.479 happens it that also happens in Superman too. Yeah, okay, okay, 0:07:06.560 --> 0:07:09.120 I totally forgot about it. Well, I've seen four more 0:07:09.200 --> 0:07:12.680 recently than two. That's there's so much wrong. And what 0:07:12.800 --> 0:07:15.440 you just said Superman four, by the way, one of 0:07:15.480 --> 0:07:18.440 the memories I would love to earth, that would be 0:07:18.560 --> 0:07:20.360 that would be great. But then how would you remember 0:07:21.000 --> 0:07:23.600 the bad guy with his press on nails? And I 0:07:23.640 --> 0:07:26.280 wouldn't and it would make me a happier person. But 0:07:26.720 --> 0:07:30.240 we're getting that's fair. Yeah, we've have we been on 0:07:30.320 --> 0:07:33.560 track yet. No. I think we've just talked about how 0:07:33.600 --> 0:07:36.200 how often people bring up the topic of I'd really 0:07:36.200 --> 0:07:39.520 love to create fake memories or get rid of real memories, 0:07:39.640 --> 0:07:43.040 or just strengthen memories I have because I know that 0:07:43.160 --> 0:07:45.840 there are there are conditions. There's just the process of 0:07:45.880 --> 0:07:49.480 aging where people have trouble remembering stuff, and I would 0:07:49.480 --> 0:07:52.040 like to hold onto those memories for as long as possible. Yeah, 0:07:52.080 --> 0:07:55.080 So I guess the question within the realm of this 0:07:55.160 --> 0:07:59.600 podcast is is it possible we could actually do that technologically. 0:08:00.040 --> 0:08:02.920 So to answer that question, first, we have to explore 0:08:03.120 --> 0:08:06.760 what exactly is a memory. Now. On one level, of 0:08:06.840 --> 0:08:11.000 memory is a recollection of some stimuli that you encountered 0:08:11.000 --> 0:08:14.240 in the past. And that sounds vague, but it's because 0:08:14.320 --> 0:08:18.640 memory is a really big topic, right and we still 0:08:18.640 --> 0:08:20.800 don't know exactly how it works all the time. The 0:08:20.800 --> 0:08:23.040 brain is a little bit mysterious, but but there is 0:08:23.080 --> 0:08:26.080 a physical process that we have more or less identified 0:08:26.520 --> 0:08:29.720 what's going on when we form and recall memories. So 0:08:29.880 --> 0:08:35.160 I'd say the brain is more than a little bit mysterious. Yeah, 0:08:35.520 --> 0:08:40.600 she's so. So we have a several regions of our 0:08:40.640 --> 0:08:43.520 brains right there. It's not just one big massive gray 0:08:43.559 --> 0:08:47.320 matter with no differentiation between one part in the next. Uh. 0:08:47.360 --> 0:08:50.640 There is one region called the hippocampus, which is associated 0:08:50.679 --> 0:08:53.840 with forming long term memories. It's where hippopotamuses go to college. 0:08:53.960 --> 0:08:57.400 That's actually, yes, the hippocampus would be a big hippo 0:08:57.440 --> 0:09:00.720 on campus. I don't know that you're allowed to talk anymore. Uh. 0:09:00.800 --> 0:09:03.520 So this is part of the forebrain, and it's located 0:09:03.520 --> 0:09:07.800 inside the medial temporal lobe, and memories are made up 0:09:07.880 --> 0:09:11.400 of neurons that communicate with each other through synapses. Now, 0:09:11.400 --> 0:09:15.360 synapses are those gaps between one neuron and other neurons, 0:09:15.400 --> 0:09:18.080 And of course neurons are the basic nerve cells in 0:09:18.120 --> 0:09:21.319 the brain exactly. So in the brain we have around 0:09:21.400 --> 0:09:24.760 between you know, eighty billion and a hundred billion neurons. 0:09:25.200 --> 0:09:27.760 A single neuron can have synapses that allow it to 0:09:27.760 --> 0:09:31.400 communicate with thousands of other neurons. It's not just a oh, 0:09:31.440 --> 0:09:34.400 it can communic yeah, or even a one to a 0:09:34.480 --> 0:09:37.760 dozen thing. We're talking about the potential to uh, to 0:09:37.960 --> 0:09:41.720 communicate with hundreds or thousands of other cells. Again, depending 0:09:41.760 --> 0:09:43.840 upon the complexity of the brain we're looking at now 0:09:43.920 --> 0:09:47.120 with human brains, it's pretty darn complex. So how do 0:09:47.240 --> 0:09:50.000 neurons make memories? Do they what do they make new 0:09:50.040 --> 0:09:53.760 neurons or do they they form pathways of communication within 0:09:53.800 --> 0:09:58.520 the hippocampus. So I kind of imagine that this is oversimplifying, 0:09:58.800 --> 0:10:01.359 and and again this is base upon our current understanding 0:10:01.360 --> 0:10:04.240 of memory. Keeping in mind that we don't have a yeah, 0:10:04.240 --> 0:10:07.320 we don't have a complete picture, but they form a 0:10:07.360 --> 0:10:11.560 pathway when you encounter us a stimuli that you need 0:10:11.600 --> 0:10:14.439 to remember something, let's say it's short term memory. They 0:10:14.559 --> 0:10:17.920 end up communicating with one another through electrochemical means. That's 0:10:18.000 --> 0:10:21.800 the way neurons communicate, and in short term memory, they 0:10:21.840 --> 0:10:26.280 just do a really quick and dirty, short electrochemical response 0:10:26.520 --> 0:10:29.079 that can be repeated a couple of times as necessary 0:10:29.120 --> 0:10:32.160 for you to remember something while it's happening at the time. So, 0:10:32.320 --> 0:10:34.120 you know, short term memory where you're able to remember 0:10:34.120 --> 0:10:35.520 something for a couple of minutes, and then if you 0:10:35.520 --> 0:10:37.200 don't think about it, if you don't really try to 0:10:37.240 --> 0:10:41.120 commit it to memory, it's gone. That's what we're talking 0:10:41.160 --> 0:10:43.320 about here. If you want to try and convert something 0:10:43.360 --> 0:10:45.360 into a long term memory where you're trying to really 0:10:45.400 --> 0:10:47.880 remember something, trying to get a concept down, like you're 0:10:47.920 --> 0:10:50.800 studying for a test and you're you're taking you know, 0:10:51.120 --> 0:10:53.400 you're reading this one passage, then resting for a while, 0:10:53.440 --> 0:10:55.040 and then reading the passage again and making sure you 0:10:55.160 --> 0:10:59.360 understand it. This is where those that same communication pathway 0:10:59.400 --> 0:11:01.960 gets repeated, but now it's repeated with different proteins to 0:11:02.040 --> 0:11:04.920 kind of make it a more hesitate to use the 0:11:04.920 --> 0:11:09.360 word permanent, but a more stable pathway. All right, So 0:11:09.400 --> 0:11:11.480 you've got these neurons that are creating this same sort 0:11:11.520 --> 0:11:15.559 of pathway. Whenever you remember that thing that you've committed 0:11:15.559 --> 0:11:21.880 to memory, this pathway reforms, mostly because they're the actual 0:11:21.960 --> 0:11:25.040 process of remembering. It turns out that we have to 0:11:25.520 --> 0:11:28.520 forge this pathway over and over again. Whenever we're filing 0:11:28.520 --> 0:11:31.640 the memory away, we're essentially recreating the memory that was 0:11:31.720 --> 0:11:34.240 created the first time. This is something that came out 0:11:34.280 --> 0:11:37.679 of studies that were started in the nineteen sixties really 0:11:37.720 --> 0:11:41.000 and then uh, you know, it didn't get widespread um 0:11:41.040 --> 0:11:45.600 acceptance within the brain research field until later. The common 0:11:45.679 --> 0:11:48.800 thought was that once you've created a long term memory, 0:11:49.280 --> 0:11:52.079 you ended up consolidating it. That's what they called it 0:11:52.120 --> 0:11:55.320 was consolidation, and that your your memory was pretty much 0:11:55.440 --> 0:11:58.120 set like you would put it into long term memory, 0:11:58.320 --> 0:12:01.080 You're good to go. Uh. As it turns out that's 0:12:01.080 --> 0:12:04.320 not exactly what happens. You have this reconsolidation that happens 0:12:04.320 --> 0:12:07.320 where every time you are filing that memory away again 0:12:07.480 --> 0:12:10.199 so that you can recall it later, you are essentially 0:12:10.240 --> 0:12:13.839 re encoding that memory. And that means that you could 0:12:14.160 --> 0:12:17.160 alter the memory through the re encoding process, so little 0:12:17.200 --> 0:12:19.880 details could change. This might be why if you hear 0:12:19.920 --> 0:12:23.160 someone tell the same story and you've known this person forever, 0:12:23.800 --> 0:12:26.559 you you think that's not the way that story goes. 0:12:26.760 --> 0:12:29.000 They totally left out this other part, or I don't 0:12:29.040 --> 0:12:31.520 ever remember hearing this thing they said this other time. 0:12:31.720 --> 0:12:34.760 It might not be because they are trying to mislead 0:12:34.760 --> 0:12:37.920 you on purpose, but rather because they literally remember it 0:12:37.960 --> 0:12:42.560 differently exactly. The memory itself is different because the process 0:12:42.559 --> 0:12:46.160 of recalling a memory changes that memory. So as a 0:12:46.160 --> 0:12:50.320 as a related tangent, this should tell you that if 0:12:50.360 --> 0:12:52.640 the nature of memory is such that we re encode 0:12:52.640 --> 0:12:55.600 our memories every time we file them away, that tells 0:12:55.640 --> 0:12:59.840 you that relying upon memory for important stuff is not 0:13:00.120 --> 0:13:03.040 always a great idea and should perhaps not be relied 0:13:03.080 --> 0:13:06.199 upon as heavily as it is. And say, like court cases, 0:13:06.400 --> 0:13:09.960 that's a great example. Yeah, so in a court case, 0:13:10.040 --> 0:13:13.200 you know, it's we often see that people put more 0:13:13.240 --> 0:13:17.800 importance on witness testimony than they do on other types 0:13:17.840 --> 0:13:22.480 of evidence. Not. Yeah, we're not. This is obviously a generalization. 0:13:22.679 --> 0:13:24.840 It's not the case in every court case, but it's 0:13:24.840 --> 0:13:27.480 something that we see as a trend where people put 0:13:27.840 --> 0:13:30.760 the human element ends up having a greater impact on 0:13:30.880 --> 0:13:34.040 us than uh than either um, you know, things that 0:13:34.040 --> 0:13:38.280 we just have to uh conceptualize or just random pieces 0:13:38.320 --> 0:13:41.160 of information. The human element often seems to have a 0:13:41.160 --> 0:13:44.400 greater impact on us, which is unfortunate because memory is 0:13:44.440 --> 0:13:49.280 not infallible. It doesn't mean that it's completely unreliable either, 0:13:49.800 --> 0:13:51.800 but it does mean that just by the very physical 0:13:51.880 --> 0:13:55.000 nature the way memories are formed, we cannot be completely 0:13:55.000 --> 0:13:58.560 certain that what we remember is exactly what has happened. Uh. 0:13:58.640 --> 0:14:02.040 It's a little worrisome or freeing, depending upon your point 0:14:02.040 --> 0:14:05.040 of view. I at this point wipe my hands of 0:14:05.120 --> 0:14:09.000 all responsibility, Like, Jonathan, you did this terrible thing. I 0:14:09.040 --> 0:14:11.160 have no memory of that, and I can be honest 0:14:11.320 --> 0:14:14.040 or at least that's not the way I remember it. Um. 0:14:14.040 --> 0:14:17.280 But but even outside of this accidental changing of memories 0:14:17.280 --> 0:14:19.640 that happens, there has been a little bit of research 0:14:19.760 --> 0:14:24.000 right into how we can purposefully alter memory absolutely and 0:14:24.160 --> 0:14:27.520 a lot of this comes from some some studies that 0:14:27.600 --> 0:14:30.720 again started in the nineteen sixties, experiments that looked at 0:14:30.720 --> 0:14:33.720 the hippocampus and the way that memories are formed. One 0:14:33.840 --> 0:14:36.160 of the things that were that we looked at was 0:14:36.640 --> 0:14:39.840 the fact that if you stimulate neurons in the hippocampus. 0:14:40.360 --> 0:14:43.120 You can make them better at communicating with each other. 0:14:43.160 --> 0:14:45.760 You can boost their ability to communicate, which means that 0:14:45.800 --> 0:14:49.600 you could help memories form more quickly, or you could 0:14:49.600 --> 0:14:54.200 reinforce a memory, reinforcing that pathway. Uh. They used the 0:14:55.000 --> 0:14:59.320 electrical stimulation, and they called the process long term potential ation, 0:14:59.520 --> 0:15:02.360 also known LTP, which is pretty much how I'm going 0:15:02.360 --> 0:15:06.200 to say it from here on out, because potential ation 0:15:06.400 --> 0:15:12.120 I trip over it pretty frequently. So long term potential 0:15:12.120 --> 0:15:16.240 ation was suspected by some to play a really important 0:15:16.320 --> 0:15:21.240 role in encoding memories, but it wasn't necessarily again accepted 0:15:21.440 --> 0:15:25.280 as a widespread concept for a while. They their brain 0:15:25.280 --> 0:15:27.480 researchers who said, well, it's obviously important, but I don't 0:15:27.480 --> 0:15:31.280 know that's the primary uh cause. And more importantly, we 0:15:31.320 --> 0:15:34.960 don't have enough direct evidence, right, because that's how science works. 0:15:35.240 --> 0:15:38.600 We can create a hypothesis, but until we test that 0:15:38.680 --> 0:15:42.000 hypothesis repeatedly and get the same result, we can't really 0:15:42.600 --> 0:15:46.760 draw a firm conclusion. That's the difference between hypothesis and theory. 0:15:47.800 --> 0:15:49.960 And even theories can change, but they are more of 0:15:50.040 --> 0:15:54.080 a kind of consolidated uh, body of information that we 0:15:54.200 --> 0:15:56.680 understand about some aspect of the universe. And they're also 0:15:56.720 --> 0:15:59.480 different from the colloquial use of the word theory, in 0:15:59.520 --> 0:16:01.440 which you can say, well, I've got a theory that 0:16:01.520 --> 0:16:07.520 it's a demon, um, but so a singing demons right there, 0:16:09.760 --> 0:16:14.200 right exactly? Anyway, Yeah, sorry, back back to any sort 0:16:14.240 --> 0:16:16.080 of buffy quote and I'm going to jump all over it. 0:16:16.400 --> 0:16:19.600 Rats at any rate. Rights. Yeah, so rats and mice, Uh, 0:16:19.680 --> 0:16:22.480 their experiments have been done with both with with LTP 0:16:22.720 --> 0:16:26.360 and forming of memories as well as erasing memories. But 0:16:26.400 --> 0:16:28.360 I'll get to that in a second. So how can 0:16:28.400 --> 0:16:31.320 you tell if a mouse or a rat is remembering something? 0:16:31.640 --> 0:16:33.400 You can't really sit down with the mouse or rats. 0:16:33.560 --> 0:16:37.600 Hey do you remember that one wheel of cheese? Man? 0:16:37.760 --> 0:16:41.320 That was awesome? It doesn't really work. So one of 0:16:41.360 --> 0:16:44.400 the very common ways, here's where we get into the 0:16:44.400 --> 0:16:47.200 the part of the podcast that could very much upset 0:16:47.240 --> 0:16:51.000 some people, because we're talking about experimenting upon animals. Uh 0:16:51.040 --> 0:16:53.960 in the name of science. This is uh. One of 0:16:53.960 --> 0:16:57.520 the ways is conditioning them to fear a certain stimulus 0:16:57.560 --> 0:17:01.239 by following up that stimulus, well a little electric zap, 0:17:01.280 --> 0:17:05.240 so not enough to to really harm them enough to 0:17:05.440 --> 0:17:08.840 enough for it to be a pain stimulus. So you're 0:17:09.000 --> 0:17:11.640 usually you're talking about like a certain pitch of sound 0:17:12.000 --> 0:17:13.520 and then you follow that up with a zap. Now, 0:17:13.600 --> 0:17:16.480 rats catch onto this really quickly from what I understand, 0:17:16.520 --> 0:17:18.760 you usually only have to do it once. And then 0:17:18.800 --> 0:17:21.720 they learned to associate the sound with getting zapped. And 0:17:21.760 --> 0:17:25.000 if you play the sound again, they freeze in anticipation 0:17:25.160 --> 0:17:30.240 of the oncoming zap, So they build that memory very quickly. Um. 0:17:30.280 --> 0:17:34.080 But in order to try and test this LTP idea, 0:17:34.240 --> 0:17:37.040 what scientists would do is back in the nineties sixties, 0:17:37.080 --> 0:17:39.600 they started uh started doing this, and then they continue 0:17:39.640 --> 0:17:44.199 that into the eighties. They would establish something like the 0:17:44.240 --> 0:17:46.880 sound and the zapp, and then they would introduce some 0:17:47.000 --> 0:17:52.000 form of inhibitor that would inhibit LTP from taking place. 0:17:52.200 --> 0:17:54.000 It would either be a drug or sometimes they would 0:17:54.040 --> 0:17:56.600 introduce a gene that would inhibit lt P, and then 0:17:56.640 --> 0:17:58.439 they would observe the rats and they saw that the 0:17:58.520 --> 0:18:02.200 rats would not be able to form a memory connecting 0:18:02.400 --> 0:18:05.920 the sound to getting zapped, or they would just essentially 0:18:05.920 --> 0:18:08.720 forget like they you could play the sound and they 0:18:08.720 --> 0:18:11.760 wouldn't freeze, they didn't associate it anymore. They had forgotten 0:18:11.920 --> 0:18:16.440 that association, and that was some that was leaning more 0:18:16.480 --> 0:18:19.720 towards the evidence that LTP has this role in encoding memories, 0:18:19.720 --> 0:18:23.480 but still wasn't exactly conclusive. It was one of those 0:18:23.480 --> 0:18:25.800 things where says, all right, well, this is promising, let's 0:18:25.840 --> 0:18:28.800 continue research and seeing what else we can find. So 0:18:28.880 --> 0:18:32.240 that was the basis for that early LTP research. We'll 0:18:32.240 --> 0:18:34.520 get back to that in just a minute. Right. What 0:18:34.720 --> 0:18:38.080 might have something to do with this is something called 0:18:38.359 --> 0:18:41.800 dendrid ex spines. And there's one study in particular that 0:18:41.880 --> 0:18:44.800 came out of NY you that was about sleep and 0:18:44.840 --> 0:18:48.159 how sleep strengthens memory. That has a lot to do 0:18:48.240 --> 0:18:51.880 with this, Okay, So, um, dendrid expines are these little 0:18:51.880 --> 0:18:56.080 protrusions between neurons and they facilitate the transfer of signals 0:18:56.119 --> 0:19:00.080 across synapses. Right. They grow in mice at least in 0:19:00.119 --> 0:19:02.879 the first few hours after the mice have learned a 0:19:02.920 --> 0:19:05.919 new skill. So this is something that actually develops throughout 0:19:05.920 --> 0:19:08.199 the lifetime of the mouse as the mouse learns, you know, 0:19:08.320 --> 0:19:11.800 differential equations and right, you know how to do a 0:19:11.880 --> 0:19:14.679 Ronney dangerfield impression, that kind of thing exactly. Um, And and 0:19:14.560 --> 0:19:18.680 and they and they strengthen that memory of that skill UM, 0:19:18.840 --> 0:19:23.080 and these researchers found that these structures grow more during sleep. 0:19:23.200 --> 0:19:25.359 They trained two sets of mice at a task and 0:19:25.400 --> 0:19:28.160 then let one set sleep for seven hours and kept 0:19:28.240 --> 0:19:31.320 the others awake for seven hours. The sleep deprived mice 0:19:31.440 --> 0:19:35.640 had less dendritic spine growth. Furthermore, they tracked which brain 0:19:35.680 --> 0:19:39.560 cells activated during the learning process, and those same brain 0:19:39.600 --> 0:19:44.040 cells reactivated while the mice were asleep, UM, specifically while 0:19:44.040 --> 0:19:46.320 they were in deep sleep, which is a slow wave 0:19:46.400 --> 0:19:49.280 sleep it's sometimes called, which is when the brain waves 0:19:49.320 --> 0:19:54.040 slowed down and dreaming and and or rapid eye movement stops. This. 0:19:54.040 --> 0:19:58.439 This is really interesting for many reasons. This is some 0:19:58.480 --> 0:20:01.480 of the kind of current re search that's being done 0:20:01.520 --> 0:20:06.960 into exactly why this kind of long term memory formation happens. UM. 0:20:07.160 --> 0:20:09.000 In a separate study that was out of the Script's 0:20:09.000 --> 0:20:13.560 Research Institute, scientists UH did some of that inhibition thing 0:20:13.640 --> 0:20:16.560 that that you were talking about earlier. They inhibited the 0:20:16.600 --> 0:20:19.920 growth of dendrid expines a few days after training mice 0:20:19.960 --> 0:20:24.280 to associate methamphetamines with a few different site, touch and 0:20:24.359 --> 0:20:28.840 scent clues. Later on, the mice lost all interest in 0:20:28.880 --> 0:20:33.280 those drug associated cues. While still maintaining longer held food 0:20:33.280 --> 0:20:37.920 reward memories. So they're they're hoping that this could lead 0:20:37.920 --> 0:20:42.359 to ways of selectively removing harmful memories like related to 0:20:42.400 --> 0:20:46.480 addiction or to PTSD or something like that, while still 0:20:46.600 --> 0:20:50.320 maintaining other other memories. Yeah, So in other words, you're 0:20:50.359 --> 0:20:54.000 not doing a full system wipe. You're wiping ones that 0:20:54.119 --> 0:20:59.280 are causing uh, possible distress or problems in a person's life. Obviously, 0:20:59.400 --> 0:21:02.199 right now we're talking think about rodents, not people. And 0:21:02.240 --> 0:21:04.800 we'll we'll touch on that again in just a moment 0:21:04.840 --> 0:21:07.600 because and that's very important to remember rats brains and 0:21:07.680 --> 0:21:12.959 human brains in most cases. Yeah, but we've got some 0:21:13.000 --> 0:21:16.000 different stuff going on for most human beings. It's true 0:21:17.040 --> 0:21:21.440 there may be exceptions at any rate moving on. So 0:21:21.560 --> 0:21:24.119 that's a great point, and we'll reiterate that when we 0:21:24.160 --> 0:21:26.480 get to a little bit further along in our podcast. 0:21:26.800 --> 0:21:29.280 We wanted to talk about another concept that's going to 0:21:29.400 --> 0:21:34.240 fold into this, optogenetics. Yeah, I thought this was really interesting. 0:21:34.320 --> 0:21:38.359 So optogenetics is a fairly new tool in neuroscience, and 0:21:38.400 --> 0:21:41.320 it's when you genetically engineer cells, which in this case 0:21:41.359 --> 0:21:45.600 would be neurons brain cells, to become light sensitive, so 0:21:45.720 --> 0:21:49.680 you can either activate them or inhibit their activity with 0:21:50.040 --> 0:21:53.400 light with light waves, making it much easier to study 0:21:53.480 --> 0:21:55.840 and manipulate these cells. So it's a really simple on 0:21:55.960 --> 0:21:59.280 and off s which as opposed to the complex neurochemicals 0:21:59.280 --> 0:22:02.480 and electrical signals that normally happen in a brain exactly. So, 0:22:02.760 --> 0:22:06.080 for one example, you can make neurons light sensitive by 0:22:06.160 --> 0:22:09.359 adding proteins called and I hope I'm pronouncing this right 0:22:09.720 --> 0:22:16.119 channel rhodopsins sounds good to me, abbreviated the two different 0:22:16.160 --> 0:22:18.880 kinds of them, c HR one and c HR two um, 0:22:18.920 --> 0:22:22.560 and you'll see these pop up sometimes in studies of optogenetics. 0:22:22.600 --> 0:22:26.680 These proteins occur naturally in algae, a certain type of 0:22:26.720 --> 0:22:30.920 algae that use light sensitive spots to help steer themselves 0:22:30.920 --> 0:22:33.720 towards sunlight and water. They've got these flagella and they 0:22:33.760 --> 0:22:38.280 operate moving toward the light when the light strikes the spot. 0:22:38.720 --> 0:22:41.879 But once animal neurons are upgraded with for example c 0:22:42.160 --> 0:22:46.879