WEBVTT - The Livewired Brain with David Eagleman 0:00:03.040 --> 0:00:05.400 Welcome to Scoot to Blow Your Mind production of My 0:00:05.480 --> 0:00:14.640 Heart Radio. Hey, welcome to Stuff to Blow Your Mind. 0:00:14.720 --> 0:00:17.680 My name is Robert Lamb. Joe is away from work. 0:00:17.760 --> 0:00:20.440 He's realigning his gray matter at the moment, so it's 0:00:20.480 --> 0:00:24.120 just me today, but I'll be joined by neuroscientist, author, 0:00:24.200 --> 0:00:28.479 and science communicator David Eagelman about his new book Live Wired, 0:00:28.600 --> 0:00:32.160 The Inside Story of the Ever Changing Brain. Now we've 0:00:32.200 --> 0:00:35.600 mentioned David Eagelman on the show many times before. He's 0:00:35.800 --> 0:00:39.199 an adjunct professor at Stanford University and his CEO of 0:00:39.360 --> 0:00:43.519 Neo Sensory, a company that develops devices for sensory substitution. 0:00:43.960 --> 0:00:46.320 You may also know him from his previous books about 0:00:46.320 --> 0:00:49.720 the human brain, his TV series The Brain with David Eagleman, 0:00:50.040 --> 0:00:53.160 and his role as a scientific advisor on HBO's Westworld, 0:00:53.479 --> 0:00:56.760 and the t NT series Perception. I'm recording this on 0:00:56.800 --> 0:00:59.680 a Monday, and I actually read Live Wired over the weekend. 0:01:00.000 --> 0:01:02.440 It's a highly addictive read and one that I think 0:01:02.480 --> 0:01:05.080 our listeners will will really enjoy. David does an amazing 0:01:05.160 --> 0:01:08.520 job breaking down the inner workings of the brain via 0:01:08.640 --> 0:01:12.880 relatable pop culture and historical metaphors. Everything from the Colonization 0:01:12.920 --> 0:01:16.160 of the America's to Mr Potato Head and Ellen Ripley 0:01:16.240 --> 0:01:19.840 from Aliens. It's published by Pantheon Books and you can 0:01:19.880 --> 0:01:22.760 currently grab it as a hardcover, an e book, or 0:01:22.840 --> 0:01:24.880 an audio book. And the fun thing is that that 0:01:25.000 --> 0:01:27.399 David reads the audio book. It's always great when you 0:01:27.440 --> 0:01:30.600 when you get that with an audio book. So, without 0:01:31.000 --> 0:01:37.080 without any further ado, let's jump right in. David Eagleman, 0:01:37.120 --> 0:01:39.319 thanks for joining me today. Great to be here, Robert. 0:01:39.440 --> 0:01:41.160 First of all, I have I just have to say 0:01:41.200 --> 0:01:43.560 that this book was such an engaging read. Actually read 0:01:43.600 --> 0:01:46.440 it all over the weekend, and while I was familiar 0:01:46.520 --> 0:01:49.920 with some of the findings and technologies discussed, there was 0:01:49.960 --> 0:01:51.800 plenty I hadn't been exposed to yet, and it was 0:01:51.840 --> 0:01:54.000 all delivered in such a fashion that it all ended 0:01:54.080 --> 0:01:57.360 up feeling like, you know, it's kind of like a revelation. Um, 0:01:57.480 --> 0:02:00.720 and I feel like that revelation is really well summarized 0:02:00.760 --> 0:02:03.920 in the title of the book, live Wired. If you would, 0:02:04.080 --> 0:02:07.640 could you summarize the basic difference between the idea of 0:02:07.680 --> 0:02:10.800 the live wired understanding of our brain as opposed to 0:02:10.960 --> 0:02:14.320 previous notions of how the brain worked. Yeah, I mean 0:02:14.360 --> 0:02:16.880 the whole The whole thing is that when you first 0:02:16.880 --> 0:02:19.520 pick up a neuroscience textbook as a young person, you 0:02:19.560 --> 0:02:21.720 see a picture of the brain and it says this 0:02:21.800 --> 0:02:23.799 parts or visions, parts are hearing, the parts are touch, 0:02:23.840 --> 0:02:27.560 and so on. But in fact, UM, I guess what 0:02:27.560 --> 0:02:29.680 I've spent the last twenty years, you know, in my 0:02:29.760 --> 0:02:33.480 laboratory really understanding the lesson of is that the brain 0:02:33.600 --> 0:02:37.360 is a is a dynamic system that's constantly moving around. 0:02:37.440 --> 0:02:40.160 And so, for example, if you go blind, the part 0:02:40.240 --> 0:02:42.440 that we would have called your visual system gets taken 0:02:42.480 --> 0:02:45.040 over by hearing and touch. If you lose an arm, 0:02:45.160 --> 0:02:47.240 the part of your body map that has an arm 0:02:47.280 --> 0:02:50.280 gets taken over by neighboring areas, and so on. The 0:02:50.280 --> 0:02:53.880 whole thing is this incredibly dynamic system. It's not like 0:02:54.000 --> 0:02:56.560 anything that we know how to build. Um. You know, 0:02:56.639 --> 0:02:58.880 here in Silicon Valley where I live, everything is about 0:02:58.919 --> 0:03:03.000 hardware and software, and engineers are praised for building an 0:03:03.040 --> 0:03:06.680 efficient system where you've got these two layers and that's it, um. 0:03:06.720 --> 0:03:10.760 But what's happening in our skulls is an entirely different 0:03:10.840 --> 0:03:14.720 kind of technology. And so I in the book, I 0:03:14.800 --> 0:03:17.040 ended up coining a new term for this live Wired 0:03:17.560 --> 0:03:20.640 or live where. And the idea with live where is 0:03:20.680 --> 0:03:24.960 that every moment of your life, this is reconfiguring itself. 0:03:24.960 --> 0:03:28.200 So you've got eighty six billion neurons, these are the 0:03:28.200 --> 0:03:31.040 cell types in the brain. You've got about point two 0:03:31.160 --> 0:03:36.520 quadrillion connections, and every moment in your life, these things 0:03:36.520 --> 0:03:40.640 are changing their strength of connection. They're unplugging, they're replugging elsewhere, 0:03:40.680 --> 0:03:45.520 they're seeking around. What you have are these dense jungles. 0:03:46.160 --> 0:03:48.680 And you know, this level of complexity is something that 0:03:48.720 --> 0:03:51.040 bankrupts our language. We don't have any way of talking 0:03:51.040 --> 0:03:55.960 about point two quadrillion connections moving and changing. But everything 0:03:55.960 --> 0:04:00.440 in your life, every experience that you have, UM changes 0:04:00.480 --> 0:04:02.880 who you are. When you learn, for example, that my 0:04:02.960 --> 0:04:05.520 name is David, there's a physical change in the structure 0:04:05.560 --> 0:04:07.280 of your brain. And that's what it means for you 0:04:07.320 --> 0:04:09.800 to then remember, you know, two months later, who's the 0:04:09.800 --> 0:04:12.080 guy you had on your podcast David. You know, it's 0:04:12.080 --> 0:04:16.080 like it's it's this constantly changing system and it's UM 0:04:16.160 --> 0:04:19.800 unlike anything that we know how to build at the moment. 0:04:19.920 --> 0:04:23.400 So UM you know, as you as you saw in 0:04:23.440 --> 0:04:25.920 the book, I tell these different stories just by way 0:04:25.920 --> 0:04:30.440 of introduction that are so fascinating, Like you can take 0:04:30.480 --> 0:04:32.960 out half the brain in a child. For example, when 0:04:33.040 --> 0:04:36.560 children have this really bad type of epilepsy, there's a 0:04:36.560 --> 0:04:38.719 surgery that they go through. Half the brain is removed, 0:04:38.880 --> 0:04:42.520 and they're just fine cognitively, they're totally fine because the 0:04:42.560 --> 0:04:45.000 rest of their brain, the other half says, Okay, I'm 0:04:45.000 --> 0:04:48.360 gonna rewire the functions that are that went missing from there. 0:04:49.240 --> 0:04:51.599 Sometimes a child is born with only half a brain, 0:04:52.160 --> 0:04:55.360 you know, and things just get get rewired so that 0:04:55.480 --> 0:04:58.680 it all is there and we can't you know, you 0:04:58.680 --> 0:05:01.320 can't do this with your cell phone or your computer. 0:05:01.400 --> 0:05:03.840 You can't take out half the circuitry and expect it 0:05:03.920 --> 0:05:07.120 to still function. But it works just fine, especially with 0:05:07.160 --> 0:05:09.400 a young brain. Now, with all of this in mind, 0:05:09.960 --> 0:05:13.480 into this live wired understanding of the brain in mind, um, 0:05:14.160 --> 0:05:17.160 I thought we might back up to a very basic question. Uh. 0:05:17.440 --> 0:05:19.600 Sometimes I guess we don't think about because we're I mean, 0:05:19.680 --> 0:05:22.120 we were trapped in the brain. We can't see the 0:05:22.160 --> 0:05:24.920 forest for the trees. But what what does the brain do? 0:05:25.560 --> 0:05:29.600 So the brain is locked in silence and darkness inside 0:05:29.600 --> 0:05:31.880 the vault of your skull, and all it's trying to 0:05:31.920 --> 0:05:35.080 do is make a model of the world, as in, 0:05:35.160 --> 0:05:38.360 I've got all this incoming data. And by the way, 0:05:38.600 --> 0:05:42.160 the data that comes into the brain is just spikes, 0:05:42.200 --> 0:05:45.360 just little electrical spikes, and these neurons. It doesn't know 0:05:45.560 --> 0:05:48.640 that these spikes represent photons, and these spikes represent air 0:05:48.680 --> 0:05:52.200 compression waves, and these spikes represent mixtures of molecules hitting 0:05:52.200 --> 0:05:54.320 a membrane and so on. All it knows is I've 0:05:54.320 --> 0:05:58.239 got data coming in as zeroes and ones and um 0:05:58.279 --> 0:06:02.000 and it knows that it can can troll a body. 0:06:02.279 --> 0:06:04.760 And so it's job is to figure out, all right, 0:06:04.760 --> 0:06:06.520 how do I control the body? How does that change 0:06:06.560 --> 0:06:08.280 the spikes coming in? And how do I make a 0:06:08.320 --> 0:06:12.839 model of the world. And this is an extraordinary technology 0:06:12.839 --> 0:06:16.520 that we have carrying around on our shoulders. Um, As 0:06:16.560 --> 0:06:19.320 I said, we we don't know how to build technology 0:06:19.320 --> 0:06:21.080 like this, and we're just scratching the surface of even 0:06:21.080 --> 0:06:23.240 trying to figure this out. But that's what the brain 0:06:23.320 --> 0:06:27.560 is doing, locked in its in its vault, is figuring out, Okay, 0:06:27.560 --> 0:06:30.120 how do I understand the world. And and it's really 0:06:30.120 --> 0:06:35.040 extraordinarily good at at extracting patterns and eventually making predictions 0:06:36.279 --> 0:06:39.120 and um, yeah, that is that is the main job 0:06:39.160 --> 0:06:41.320 that is trying to accomplish. Now, the big part of 0:06:41.320 --> 0:06:44.120 the book deals with how our senses, uh you know, 0:06:44.160 --> 0:06:46.440 speak to the brain and how the brain works around 0:06:46.520 --> 0:06:49.440 limitations uh such as that are the ones you mentioned 0:06:49.440 --> 0:06:51.520 with the half of the brain being missing at etcetera. 0:06:51.560 --> 0:06:55.039 And also uh you know relating limbs uh and uh 0:06:55.120 --> 0:06:58.440 and I love how use these various metaphors to explain 0:06:58.520 --> 0:07:01.800 that to the reader. Would you mind explaining to our 0:07:01.839 --> 0:07:05.520 listeners how our brains are, like Mr potato Head. Yeah, 0:07:05.640 --> 0:07:07.840 So this is something that struck me many years ago 0:07:08.040 --> 0:07:11.040 where I realized that, so we've got all these sensors 0:07:11.080 --> 0:07:13.440 like our eyes and our ears and our nose and 0:07:14.000 --> 0:07:16.360 our fingertips. All these things were used to and so 0:07:16.440 --> 0:07:18.320 we just sort of think of these as fundamental. But 0:07:18.800 --> 0:07:20.840 but when you look across the animal kingdom, what you 0:07:20.880 --> 0:07:23.880 find are all these other weird kinds of sensors, things 0:07:23.880 --> 0:07:27.560 that you could take in like snakes taken infrared information, 0:07:28.240 --> 0:07:31.040 honey bees taken ultra violet. When you look at something 0:07:31.080 --> 0:07:34.600 like the black Ghost knifefish, it has electro receptors where 0:07:34.600 --> 0:07:39.640 it's pulling in information about perturbations and electrical fields. Um. 0:07:39.880 --> 0:07:44.160 Lots of birds and cows and insects have magneto reception 0:07:44.160 --> 0:07:46.080 where they are picking up on the magnetic field of 0:07:46.120 --> 0:07:48.720 the planet and they're navigating that way and so on. 0:07:48.840 --> 0:07:51.440 And what I realized is Mother Nature doesn't actually have 0:07:51.480 --> 0:07:55.160 to recreate the brain every time she does this. Instead, 0:07:55.440 --> 0:07:59.640 the principles of brain operation, she's figured that out at 0:07:59.680 --> 0:08:01.600 the beginning in ing, and then she can just plug 0:08:01.600 --> 0:08:04.520 in anything she wants in terms of what is the 0:08:04.560 --> 0:08:07.600 information that would be useful to sense. And that's why 0:08:07.640 --> 0:08:11.080 I suggested this potato head model of how to think 0:08:11.080 --> 0:08:13.440 about this, which is to say, you just take any 0:08:13.440 --> 0:08:15.240 sensors and you stick it in and it's good to go. 0:08:15.360 --> 0:08:17.680 The brain figures out, Okay, I've got this kind of 0:08:17.680 --> 0:08:21.840 spikes coming in um, and it seems to correlate with 0:08:21.840 --> 0:08:23.800 this other sense, and it seems to allow me to 0:08:24.000 --> 0:08:27.200 find food or avoid predators or whatever. And so it 0:08:27.240 --> 0:08:29.960 just figures out what to do with that information. And 0:08:30.000 --> 0:08:32.000 so this is a very new kind of way to 0:08:32.040 --> 0:08:35.040 think about the brain. It's essentially understanding the brain as 0:08:35.080 --> 0:08:39.120 a general purpose compute device. You feed in whatever kind 0:08:39.120 --> 0:08:41.600 of data stream you want, and it's and it's good 0:08:41.600 --> 0:08:43.400 to go. And this, you know, explains a lot of 0:08:43.440 --> 0:08:47.760 what happens evolutionarily with genetics. It just what it allows 0:08:47.840 --> 0:08:50.160 Mother Nature to do is just tweak around with the 0:08:50.160 --> 0:08:53.920 genetics to make new kinds of sensors. But one of 0:08:53.960 --> 0:08:56.240 the really amazing things you you discussed in this is 0:08:56.280 --> 0:08:59.440 that is that you can plug an eye into an 0:08:59.440 --> 0:09:01.160 ear hole or an ear into an eye hole on 0:09:01.160 --> 0:09:02.960 the Mr Potato head of our of our brain, and 0:09:03.000 --> 0:09:06.880 the brain will roll with the data that that's exactly right. 0:09:06.960 --> 0:09:11.080 And so this is an area called sensory substitution, which 0:09:11.080 --> 0:09:14.439 is to say, you can feed information into the brain 0:09:14.600 --> 0:09:17.880 via an unusual channel. And so something I started in 0:09:17.920 --> 0:09:20.240 my lab about ten years ago was seeing if we 0:09:20.280 --> 0:09:24.480 could build sensory substitution for people who are deaf. So 0:09:24.840 --> 0:09:27.240 what we do. We started by building this as a 0:09:27.360 --> 0:09:30.040 vest with vibratory motors in it. So you've got a 0:09:30.040 --> 0:09:33.320 whole bunch of little buzzers like the buzzer in your 0:09:33.320 --> 0:09:37.640 cell phone, and um, it captures sound and turns out 0:09:37.640 --> 0:09:41.480 into patterns of vibration on the torso. And it turns 0:09:41.480 --> 0:09:43.720 out that that worked really well. We could get people 0:09:43.760 --> 0:09:47.760 who are profoundly deaf to start understanding what is happening 0:09:47.760 --> 0:09:51.960 in the auditory world just predicated on this spatio temporal 0:09:52.000 --> 0:09:55.160 pattern of vibrations on their skin. And the reason it 0:09:55.200 --> 0:09:58.120 worked is because it doesn't matter how the information gets 0:09:58.120 --> 0:09:59.800 to the brain. As long as it gets there, the 0:10:00.040 --> 0:10:02.040 rain will establish the correlations and figure out what to 0:10:02.080 --> 0:10:03.800 do with it. So, as an example, if you see, 0:10:04.240 --> 0:10:06.560 you know, the dog's mouth moving and you feel the 0:10:06.600 --> 0:10:09.000 buzzing on your skin, you know, your brain puts that 0:10:09.080 --> 0:10:11.880 together really easily. Or you know, you see somebody speaking, 0:10:12.000 --> 0:10:14.440 or or we train people by showing a word and 0:10:14.520 --> 0:10:16.520 you you know, you feel the world on the vest 0:10:16.559 --> 0:10:19.600 and you start understanding what's going on. So what we 0:10:19.640 --> 0:10:22.080 did then is we shrunk it down to the size 0:10:22.120 --> 0:10:25.400 of a wrist band. And because you and I are 0:10:25.400 --> 0:10:27.520 on video, Robert, you can see the wrist band that 0:10:27.559 --> 0:10:29.120 I'm wearing right now. It's you know, it looks about 0:10:29.120 --> 0:10:32.080 the size of a fitbit and it has very sophisticated 0:10:32.080 --> 0:10:35.360 computation in here where it's capturing sound and turning that 0:10:35.360 --> 0:10:39.560 into patterns vibration around the skin of the wrist. And um, 0:10:40.040 --> 0:10:44.160 so what we've been doing is we uh this Actually 0:10:44.160 --> 0:10:46.840 now I spun a company out of my lab called 0:10:46.920 --> 0:10:51.320 neosensory and we have been on the market since March 0:10:51.480 --> 0:10:54.360 and we're now on wrists all around the world. So 0:10:54.679 --> 0:10:56.920 people who are deaf for have hearing loss of some 0:10:57.000 --> 0:10:59.880 degree where this and they are picking up on the 0:11:00.000 --> 0:11:03.440 auditory world through their skin. Now, the interesting part is 0:11:03.480 --> 0:11:05.439 this is exactly what the inner ear is doing. Your 0:11:05.480 --> 0:11:10.000 inner ear is just registering vibrations of your ear drum 0:11:10.040 --> 0:11:13.600 and it breaks sound up into from high to low frequency, 0:11:13.600 --> 0:11:15.880 and then it ships it off to the brain. And 0:11:15.920 --> 0:11:18.320 all we're doing is transferring the inner ear to to 0:11:18.440 --> 0:11:21.760 the wrist and it works. So that's the idea of 0:11:21.800 --> 0:11:26.120 sensory substitution. Is your um just getting the information there 0:11:26.440 --> 0:11:28.360 via a different route and the brain figures out what 0:11:28.440 --> 0:11:30.560 to do with it. And if this weren't amazing enough, 0:11:30.640 --> 0:11:34.040 there's this then this this other additional step, this idea 0:11:34.640 --> 0:11:37.920 of of plugging all new things into it, like new 0:11:38.080 --> 0:11:42.560 forms of sensory information, new even uh, you know, not 0:11:42.600 --> 0:11:46.720 only limbs of replacement, but artificial additional limbs. Use the 0:11:46.760 --> 0:11:50.719 example of doctor Octopus from the spider Man comics. Um, 0:11:51.559 --> 0:11:53.400 can you tell us a little bit about how even 0:11:53.480 --> 0:11:56.640 like this nineteen sixties sci fi concept is not that 0:11:56.760 --> 0:11:59.960 far removed from our current understanding of the brain. Yeah, 0:12:00.400 --> 0:12:04.080 so um, let me actually let me say two things. Actually, 0:12:04.160 --> 0:12:08.040 one is what we can do, so let me just 0:12:08.080 --> 0:12:11.559 separate out sensory information coming in and motor information going out. 0:12:11.600 --> 0:12:14.640 So sensory information coming in. One of the things we're 0:12:14.679 --> 0:12:18.640 doing with the with our wristband called buzz Um is 0:12:18.840 --> 0:12:21.720 we can not only take in sound information for people 0:12:21.720 --> 0:12:25.640 who are deaf, but we could actually expand the sensory 0:12:25.679 --> 0:12:27.559 information that you would normally have. So for example, with 0:12:27.600 --> 0:12:30.679 somebody who's not deaf, we feed in ultra violet or 0:12:30.760 --> 0:12:33.440 infrared or or things like that, where we're expanding senses 0:12:33.440 --> 0:12:35.160 that you already have. And then we're doing this other 0:12:35.200 --> 0:12:38.600 thing called sensory addition, where we're feeding in brand new 0:12:38.679 --> 0:12:41.240 senses that you've never had. So we can feed in 0:12:41.280 --> 0:12:44.080 any day to stream with this, like stock market data 0:12:44.120 --> 0:12:48.440 or Twitter data or factory information or anything at all. 0:12:49.240 --> 0:12:51.040 Feeding this in and as long as your brain can 0:12:51.040 --> 0:12:53.800 make correlations with what it's seeing or hearing around it, 0:12:54.160 --> 0:12:57.480 then the brain can figure out how to utilize that information. 0:12:57.559 --> 0:13:00.920 So we actually just finished a big developer contest where 0:13:01.000 --> 0:13:04.760 people did all kinds of projects with you know um 0:13:04.800 --> 0:13:08.640 monitoring air quality or monitoring you know, blood sugar and 0:13:08.640 --> 0:13:13.040 your bloodstream or um. Um many many different kinds of 0:13:13.200 --> 0:13:16.559 monitoring of feeling, electrical fields and so on. UM. So 0:13:16.600 --> 0:13:18.880 all this, by the way, if if anybody is interested, 0:13:18.960 --> 0:13:21.360 we have an open a p I and an s 0:13:21.440 --> 0:13:24.640 d K four buzz. You can get this on neo 0:13:24.679 --> 0:13:27.040 central dot com and pursue any kind of project you 0:13:27.080 --> 0:13:29.360 want this way. So we've had hundreds of people just 0:13:29.400 --> 0:13:31.200 making their own thing, which has been which has been 0:13:31.280 --> 0:13:34.160 very cool. Now to switch to the second thing about 0:13:34.280 --> 0:13:38.199 motor output. UM, Yeah, it turns out that your brain 0:13:38.760 --> 0:13:43.200 UM is not pre programmed to drive your body, but 0:13:43.280 --> 0:13:47.520 instead can figure out whatever the affordances are of whatever 0:13:47.600 --> 0:13:50.000 is there. So just as an example, you know, one 0:13:50.000 --> 0:13:52.040 of the things I tell the story about this dog 0:13:52.720 --> 0:13:55.000 UM that was born without four limbs. It didn't have 0:13:55.080 --> 0:13:57.640 his front legs, and so it just she walked bipetally. 0:13:57.720 --> 0:13:59.800 She walks on her back legs like a human and 0:14:00.080 --> 0:14:03.360 presumably any dog could do this, but they're not sufficiently motivated, 0:14:03.400 --> 0:14:06.480 but so she just walks around her hind legs and UM. 0:14:06.600 --> 0:14:09.640 What this illustrates is that dog brains are not pre 0:14:09.760 --> 0:14:12.559 programmed to drive dog bodies, but instead they figure out, Okay, 0:14:12.679 --> 0:14:14.000 here's what I can do. I need to get to 0:14:14.040 --> 0:14:16.120 my food, to my water, to my mother whatever. This 0:14:16.200 --> 0:14:19.800 is how I do it. And so um. Also, I 0:14:20.240 --> 0:14:21.880 you know, tell the story of the guy who's the 0:14:21.920 --> 0:14:25.440 world's best archer. He has the world's record for best 0:14:25.560 --> 0:14:28.200 archery shot, and he doesn't have arms, so he does 0:14:28.240 --> 0:14:31.640 this with his legs. And it's just another illustration that 0:14:31.680 --> 0:14:34.280 the brain figures out whatever body it's in says okay, 0:14:34.360 --> 0:14:35.920 I figure how to drive this. Of course, we see 0:14:35.920 --> 0:14:38.960 this when people, for example, get an amputation. Let's say 0:14:38.960 --> 0:14:41.440 they lose an arm in a motorcycle, accent or something. 0:14:41.880 --> 0:14:46.520 The map of their body in their brain readjusts to say, Okay, 0:14:46.560 --> 0:14:49.200 I see I've got a body without an arm, so 0:14:49.280 --> 0:14:53.760 I'm just gonna figure that out now. Okay. So, because 0:14:54.320 --> 0:14:59.680 it is not pre programmed, it's extremely flexible. Um. I 0:14:59.680 --> 0:15:02.640 think that we could actually build any kind of body 0:15:02.720 --> 0:15:06.440 we want. So um, coming back to your question, I 0:15:06.840 --> 0:15:10.359 you know mentioned about Doc Cock in the nineteen sixties, 0:15:10.520 --> 0:15:14.640 which debuted in spider Man, the scientist who plugs in 0:15:14.720 --> 0:15:17.720 four robotic arms so that he can actually do extra 0:15:17.800 --> 0:15:20.400 things and poor beakers and so on, and he controls 0:15:20.480 --> 0:15:22.160 us with his brain. But then there's an explosion his 0:15:22.240 --> 0:15:24.720 lab and he turns evil and he scales buildings and 0:15:24.800 --> 0:15:27.320 learns new forms of martial arts with with eight arms 0:15:27.320 --> 0:15:30.080 and so on, and um, Dr Octavia starts to go 0:15:30.120 --> 0:15:34.480 by Doc Dock. Anyway, UM, the exactly as you said, 0:15:34.520 --> 0:15:37.040 This is not as far off and weird as we 0:15:37.120 --> 0:15:40.000 used to think, because now what we're doing is with 0:15:40.120 --> 0:15:44.040 for example, patients who are paralyzed. Um, you can put 0:15:44.160 --> 0:15:47.680 electrodes into their motor cortex and they can learn to 0:15:47.800 --> 0:15:50.520 drive a robotic arm even though they are paralyzed. They 0:15:50.600 --> 0:15:54.000 drive the robotic arm with their thoughts, which sounds weird, 0:15:54.040 --> 0:15:56.200 but that's of course, how you drive your fleshy arm. 0:15:56.280 --> 0:15:57.840 You just you know, you think about it, you learned 0:15:57.880 --> 0:16:01.040 the you learned what the put signals are that make 0:16:01.080 --> 0:16:03.360 your arm respond. It's the same thing with the robotic arm, 0:16:03.400 --> 0:16:05.600 and you can do that. And there have been experiments 0:16:05.600 --> 0:16:10.040 with monkeys where they their bodies work fine, they're not paralyzed, 0:16:10.240 --> 0:16:12.640 but they can drive a third arm with you know, 0:16:12.680 --> 0:16:14.760 with their thoughts. So they're driving a robotic arm with 0:16:14.800 --> 0:16:17.880 their thoughts. There was an experiment done where a monkey 0:16:18.120 --> 0:16:22.480 um uses his motor cortex to make a robot walk. 0:16:22.560 --> 0:16:25.800 But the interesting part was the robot happened to be 0:16:25.880 --> 0:16:28.320 across the world. The monkey was in North Carolina and 0:16:28.360 --> 0:16:31.160 the robot was in Japan, and the signals from the 0:16:31.160 --> 0:16:33.640 monkey's brain were being sent over the internet. And you 0:16:33.680 --> 0:16:37.200 can get the robot, you know, the monkey to control 0:16:37.240 --> 0:16:40.600 the robot just with the spikes in its motor cortex. 0:16:41.040 --> 0:16:44.120 And so, UM, I think it's going to be no 0:16:44.240 --> 0:16:48.600 time at all before we really start controlling external devices 0:16:48.800 --> 0:16:51.480 with our thoughts. And one of the things, one of 0:16:51.520 --> 0:16:54.600 the frameworks that I build is this issue that what 0:16:54.640 --> 0:16:57.000 we think of as the self, what you think of 0:16:57.040 --> 0:16:59.600 as your body, just as a matter of control, what 0:16:59.680 --> 0:17:01.560 can you control with your body? And I think this 0:17:01.640 --> 0:17:05.760 is by the way, why we understand our reflections in 0:17:05.760 --> 0:17:08.680 a mirror to be us. Because you move in it moves, 0:17:08.680 --> 0:17:12.199 and so you're driving what you're seeing over there, so 0:17:12.240 --> 0:17:15.600 you think, oh, yeah, that's me over there. Um. But 0:17:15.640 --> 0:17:18.080 what this means is in you know, make up a 0:17:18.160 --> 0:17:22.680 number thirty five years, when we are controlling a robot 0:17:22.880 --> 0:17:26.199 with our thoughts, it is essentially an extension of our body. 0:17:26.880 --> 0:17:29.920 What it means is that that will become us. It 0:17:29.960 --> 0:17:33.879 will be a part of of your body. All right, 0:17:33.920 --> 0:17:35.480 we're going to take a quick break, but I'll be 0:17:35.560 --> 0:17:41.119 right back with David Eagleman. Thank alright, I'm back with 0:17:41.200 --> 0:17:44.280 David Eagleman. In the book, you talk about the live 0:17:44.359 --> 0:17:49.440 wired brain as as being a place of competition, um, 0:17:49.520 --> 0:17:52.159 based on the input that's coming in. And I was 0:17:52.200 --> 0:17:56.439 just really uh intrigued by this, this new theory of 0:17:56.520 --> 0:17:59.680 dreaming that you discuss. Would you would you mind h 0:18:00.000 --> 0:18:03.119 sharing that with our listeners. Yeah, um, yeah, this is 0:18:03.160 --> 0:18:06.160 something very cool that's come out of our studies of plasticity, 0:18:06.480 --> 0:18:10.400 and UM here it is. It's that when any part 0:18:10.440 --> 0:18:13.040 of the brain goes unused, it gets taken over. And 0:18:13.080 --> 0:18:17.919 so for example, if you go blind, your systems for 0:18:18.119 --> 0:18:20.720 hearing and touch and all of that real estate will 0:18:20.760 --> 0:18:22.520 take over the part of the brain that we used 0:18:22.520 --> 0:18:26.400 to call the visual cortex. So the surprise in neuroscience 0:18:26.400 --> 0:18:30.680 has been how rapidly this happens. Um. What group found 0:18:31.280 --> 0:18:34.480 about thirteen years ago was that if you take sighted 0:18:34.560 --> 0:18:36.840 people and you blindfold them tightly and you stick them 0:18:36.880 --> 0:18:40.000 in a brain scanner, within about an hour you can 0:18:40.080 --> 0:18:43.679 start seeing activity in the visual cortex just based on 0:18:44.480 --> 0:18:47.080 um hearing or touch. If you touch them on the 0:18:47.080 --> 0:18:50.480 hand or something, you start seeing activation in the visual cortex. Now, 0:18:50.480 --> 0:18:53.199 it's not because the neurons have had a chance to 0:18:53.280 --> 0:18:57.840 grow that fast from hearing and touch into the visual cortex. Instead, 0:18:58.160 --> 0:19:01.800 there's all kinds of cross wiring the brain where those 0:19:01.840 --> 0:19:05.120 systems are already reaching over into the visual cortex. It's 0:19:05.160 --> 0:19:07.959 just that they're normally silenced and they're inhibited, so they 0:19:07.960 --> 0:19:10.520 don't get to do anything. But that inhibition starts wearing 0:19:10.520 --> 0:19:14.720 off very quickly. And so I was really shocked by 0:19:14.840 --> 0:19:17.280 the speed at which hearing and touch could take over. 0:19:17.320 --> 0:19:18.919 And so my student and I were talking about this 0:19:18.960 --> 0:19:21.120 one day, and what we realized is there's a very 0:19:21.119 --> 0:19:23.760 critical thing that happens because we live on a planet 0:19:23.760 --> 0:19:27.560 that rotates into darkness for half the time. You know, 0:19:27.760 --> 0:19:29.600 in the dark you can still hear and touch and 0:19:29.640 --> 0:19:31.399 taste and smell and all that just fine, but you 0:19:31.440 --> 0:19:34.520 can't see. And of course I'm talking about evolutionary time, 0:19:34.560 --> 0:19:38.800 not recent electricity times. And so um, what this means 0:19:38.840 --> 0:19:40.760 is that the visual cortex has always been in a 0:19:40.800 --> 0:19:44.600 big disadvantage when the planet rotates into darkness. And so 0:19:44.640 --> 0:19:46.359 what we realized is, Wow, if it doesn't want to 0:19:46.359 --> 0:19:49.240 get taken over by the other senses, it has to 0:19:49.240 --> 0:19:52.080 have some way of defending its territory. And what we 0:19:52.160 --> 0:19:54.800 realized was that that's what dreams are. You have this 0:19:55.000 --> 0:19:58.879 very specific circuitry that starts in the midbrain and goes 0:19:58.960 --> 0:20:02.320 through a series of depths and just blasts activity into 0:20:02.400 --> 0:20:06.600 the visual cortex every night about every ninety minutes, and 0:20:06.600 --> 0:20:09.239 and that's its only job. It's just blast activity in there. 0:20:09.240 --> 0:20:12.000 It's very specialized circuitry. It's very specific of the type 0:20:12.000 --> 0:20:16.960 of thing that to the ananimouss eye is not accidental. 0:20:17.640 --> 0:20:20.960 And so and of course, because it's our visual cortex, 0:20:21.040 --> 0:20:23.440 we you know, we see and we think, oh, I'm 0:20:23.480 --> 0:20:26.560 having this full, rich visual experience. Um. And of course 0:20:26.640 --> 0:20:28.879 dream content might have to do with you know, it 0:20:28.880 --> 0:20:31.359 certainly has to do with what you've experienced during the 0:20:31.440 --> 0:20:33.600 day in which synapses are still hot and so on. 0:20:33.720 --> 0:20:36.320 But but the point is that it's just blasting activity 0:20:36.320 --> 0:20:40.840 in there to defend the visual system against takeover. And 0:20:40.880 --> 0:20:43.640 so we've now done big studies on this. For example, 0:20:43.720 --> 0:20:45.800 where I'll just give you one thing that we just 0:20:45.800 --> 0:20:48.960 published recently where we compared twenty five different species of 0:20:49.040 --> 0:20:51.960 primates and we looked at how plastic they were, because 0:20:52.000 --> 0:20:55.679 across even the primate kingdom, you have this um you know, 0:20:55.760 --> 0:20:58.840 spectrum of how plastic you drop into the world and 0:20:58.880 --> 0:21:01.040 then how much rems sleep they get in other words, 0:21:01.040 --> 0:21:03.960 how much you know, rapid eye movement or or dream sleep, 0:21:03.960 --> 0:21:06.520 because this is when dreams happen. And it turns out 0:21:06.560 --> 0:21:09.679