SIO464: All About Synesthesia, Part 2

Transcript

This transcript was generated automatically and may contain errors — the audio is the record.

0:00:16 Thomas: Hello and welcome to Serious Inquiries Only. This is episode It's part two with Dr. Jenessa Seymour on synesthesia. Is so cool. Part two maybe doesn't have the most mind -blowing thing in the world from part one that I'm still so excited about and just been thinking about. It may not have that, but it has so much more about synesthesion, what understand about it, what it is, what it isn't. And this part will even make clear something that I was kind of skeptical about in way that something that I really didn't quite understand yet that Jenessa ties together beautifully about where in the process the synesthesia is happening. You know, it can't be right away. It can't be in the beginning, the very beginning, because there seems Seems to be some sort of brain processing, but it can't be too far out in the process, to use loose language here, because we know that it's involuntary, there's different reasons. And particularly if you remember talking about the peripheral vision thing, that was really fascinating. And that felt like something that was Really Hard to Reconcile, someone's synesthesia essentially turned black and white in the same way that their peripheral vision would. Got to a certain area. That seemed hard to understand. And today's episode, among other things, in the process of helping us understand what synestesia is, actually does explain that. It's so cool. Hope you enjoy this even a tenth as much as I did. Once again, please support the show, patreon.com/seriouspod. If you like conversations like these, if you're finding it interesting, that is the way to support the Show to make sure it keeps happening. Also share with a friend, share it with someone, especially these ones are so cool. Who is not interested in synesthesia? If they aren't, then I'm not interested In them. Sorry. This is exactly the kind of thing I love talking about the on the show. And so I share it With someone. All right, after this break, we'll get to part two with Jenessa. Jenessa, welcome back.

0:02:19 Thomas: I'm doing orange. I don't know. I think of an on theme joke. But no, this is synesthesia part two, I suppose.

0:02:17 Jenessa: How you doing

0:02:29 Thomas: And my mind is still blown from the first one. I've like actively been thinking about that since we recorded that. That. Uh, it's so cool. Like I seriously almost might make a Tik TOK or something. If I ever had time of like, this might be the only person we know of who can imagine a color that they've never seen.

0:02:29 Jenessa: Awesome yeah

0:02:46 Thomas: I I mean think, that we know I'm sure there's others statistically, but not many.

0:02:46 Jenessa: Sure as far as documented evidence goes that I have come across in my extensive research on this that's that's the one I've seen yeah

0:02:59 Thomas: So cool. Uh am still thinking about that all the time. Uh now we're gonna learn more more about synesthesia right who

0:03:06 Jenessa: So I think last time we did a lot of just what is this and today Today, I'm thinking we could do a little more of like, how can this be?

0:03:14 Thomas: Is not how is yeah I'm with I'm right with yeah that's what I said too yep

0:03:23 Jenessa: You know, we've talked like just descriptively, like what is going on here? And there's a lot of themes of, you it's primarily just sensory crossing. There's a stimulus that comes in. It triggers the usual perception you would expect. And then there's this secondary perception that is unexpected, not typical. So how can that be happening? Really eliminated the they're just making it up theories or the it's just a metaphor. Metaphor it's just fluffy language kind of theories it data is pretty clear I'm sure there's individuals who are just making it up or using metaphors right

0:04:05 Thomas: Yeah that guy over there is definitely making it up your annoying friend is for sure making it out but oh and remind me I'm sure you said this but remind me the prevalence of it like the actual once we've done the test of the are you lying test like roughly what the percentage of people that have this ends up being right

0:04:08 Jenessa: Whatever sure it is ultimately still going to rely on reporting like I don't know that anybody's ever done a yeah but estimated is like probably about four percent which is still pretty high when you you think about it.

0:04:24 Thomas: You can't test everybody sure yeah that is a lot higher than I think of now is there something uh again just kind of reviewing is there Something that's a very light form of it that's getting you in that four percent that's like okay that's very low form of It but the the more like vivid kind we would think of is just like, wow, mind -blowing part of it. Maybe that's a smaller percent or what does that 4 % cover?

0:04:51 Jenessa: 4% is anybody who would fit the definition. So that could be color the graphing we talked about as letters and numbers having color uh we talked About color pitch where uh musical notes can have color mirror touch is one we didn't talk about where you know I were to touch my arm and you watched me do that you could imagine what that feels like but for people with mirror touch they would literally feel a touch sensation on their own arm yeah it so

0:05:22 Thomas: What? Okay. Now this is raising all kinds of questions because based on what I've learned about synesthesia, do people also have that with other things? Like a letter is a touch, a name is a Touch, a musical note is a Touch Or just by the nature of like I don't know, maybe how our senses are Not all like identical in terms of Our brain wiring and stuff Is touch more specific and it's just Like mirror touch is where you see that

0:05:48 Jenessa: Is really interesting um general way it's conceived of, like you'll hear as researchers talk about it, is like anything could be paired with anything. Don't know that I 100% agree because as I go through, there is a lot of diversity. So, for example, having color. So, like, you know, you can have like dull ache or like sharp pain or whatever. Some people have it where like different types of pain have different colors. Um people have um names different people's names can have a color or

0:06:17 Thomas: With my luck, my name To somebody is going to be, you know, that's Fun because I know in college a lot of the girls I was interested in seemed like my name Caused them physical pain, so So that's a hacky joke, but that would be really funny if that was like, oh, bad luck. It's like one of those sitcom rom things where it's like they love each other every other way, like they're attracted to each other, every other way. But then like, you name know, is find out the person's name and it's like causes physical pain.

0:06:43 Jenessa: Yeah no there's someone who um the example he gives is the name derrick tastes of earwax like how could he be your friend every time he hears your name yeah sorry man And so like names having a taste and textures having a taste, there is one that I never see and I can't quite put my finger on. I've never seen a, I've never seen anybody mention things having a sound.

0:06:55 Thomas: Apologies to all Derek's. Yeah. Wow. Oh, wow.

0:07:11 Thomas: Feelings having a sound. I'm trying to think. Interesting. Oh,

0:07:16 Jenessa: I have seen different sounds trigger color.

0:07:17 Thomas: It is that one. Okay. Other, yeah.

0:07:21 Jenessa: It triggers this, it triggers that. I so we have like color pitch where the sound triggers a color. I have yet to see a case where it's like, oh, that color sounds high pitched or that color Sounds tinny and this color sounds warm. Like,

0:07:31 Thomas: Interesting. I wonder if it would just be too disruptive. Like you wouldn't be able for, knows? Like just, just my first thought, like, is there some way, I don't know if it's like way back in the, uh, what is the paleolithic or whatever, where it's like, somebody is just hearing every single sensation. Like, ah, I can't deal with this. That combination when it's when it stinks for some reason but I don't know that would get awful that would be really bad

0:07:46 Jenessa: Maybe it's just, yeah, just like overstimulating. Oh, sure. And like we can all imagine sounds to some extent, right? You know, some people more vividly than others, but not this involuntary.

0:08:08 Thomas: Know that's very interesting not again I I would probably be in the liar category I donT think I have synesthesia or anything but when it comes to sound like there's there's a reason I've always been like musician and into sound like I do feel like I have more of an experience of hearing things in my brain than than most people. And I will say that there are times when, uh, there's like some sort of repeating visual pattern, I hear it. And, but like, not, not in a super vivid way, but like, I don't know, a little bit, like trying to think of an example, there've been times where I dunno, if there's some sort random computer thing that's like cycling, you know, or, or flashing at certain intervals, like like even actually, no, even GIFs, like GIFS that repeat, I start like, even with no sound, I swear, like, I started to hear them in a weird way. I also think that's probably more of my, like... I don't think it's synesthesia. I think it's like my active imagination that's always tuned into sound kind of starts like making a sound for it or something.

0:09:09 Jenessa: A really great paper that distinguishes differentiates musical imagery, which is your intentional, I'm going to listen to this song in my head, kind of, which musicians do intentionally very often.

0:09:13 Thomas: I do that all the time. Yeah. Yeah, mm

0:09:21 Jenessa: Stuck in your head, which is, they call it an earworm, which I can't stand that, and musical hallucinations, and distinguishing how those are qualitatively different, how they're experienced differently. All internal auditory experiences, but they are not actually the same thing um so what you're describing to me sounds like almost like a form of of auditory imagery it's not literally a visual image right but it's internal but it it less like intentionally oh I'm gonna think about this song and intentionally listen into this song it doesn't sound like an earworm because it's not stuck in your head but

0:09:25 Thomas: Also have that all all the time interesting no I I really think it's sort of more just like I'm sure for for most people they would have the sense of like if if you see something visually your brain is expecting to hear it probably you know and I think for me I just have maybe a little bit more overactive of that where like more things than just what you think would have that for me maybe I don't know yeah

0:10:21 Jenessa: So like if I if I see a gif especially like yeah repeating like somebody dribbling a basketball on a hard surface I my brain would start to it it almost feels like I can hear the basketball so if you mean it like that and there's a direct

0:10:34 Thomas: Kind of yeah but it's not just like direct sounds like a basketball. It's also something about the visual repeated pattern that like, I mean, I think it's still related to a sound you would expect from something repeating. This is not interesting, but anyway, it's the kind of way both our brains work where I feel like we're like, oh, we just want to figure this thing out. And I appreciate you putting thought into my nonsense.

0:10:52 Jenessa: Know sure I well actually this ties in really well because what describing is it sounds like you're kind of struggling to connect it to is it uh this strong synesthesia definition of what is definitional at least according to the researchers Right. Is OK, this is idiosyncratic. It is not there's no rational connection. There's no reason Middle Sea should be blue and not green.

0:11:24 Jenessa: Like, why would it be? We have certain forms of what they'll distinguish it from is weak synesthesia that we all have, which is essentially tendency to draw metaphors. Um, if I were to say this is a shirt, I don't mean that literally. And you know what I meant. At the same time, if you if you really step back and analyze that for a second, what the hell? That is so weird.

0:11:57 Thomas: You shouldn't. Yeah it would be hard to speak to someone who's always been blind and explain what that meant.

0:12:05 Jenessa: Yeah, like that makes no sense. But you instantly know that I don't mean mean it has bells and whistles and you know a sharp cheddar it's not poking me it's not poking the roof of my mouth

0:12:17 Thomas: Delicious. I feel like I almost tasted it right there.

0:12:21 Jenessa: Yeah so like it's have these metaphors built into our language um familiar with um booba kiki experiment okay

0:12:26 Thomas: That's interesting. All right now you're just making shit up. Oh is this the thing the sounds oh wait is this about the sounds and the whatever like there's something okay I don't remember exactly that but I do remember one where it was like some sort of visual and they asked people like which thing would have what sound and it's like pretty universal okay I feel that very strongly like that's the kind of thing I feel like oh I have a like just a bit of a dialed up experience of that is all mainly I'm I'm thinking oh

0:12:32 Jenessa: I know I I know it's, yes, exactly. So Yeah.

0:13:00 Jenessa: Exactly. So, I just sent you the picture of it. And if people aren't familiar, it's essentially, they show you these two shapes and yeah.

0:13:08 Thomas: Yeah yes I do Remember exactly this I thought it was different words than that for some reason mm

0:13:12 Jenessa: It'll, work generally with with any, words are evoking the shape essentially is what it's doing is they'll show you these two shapes and they'll say, okay, imagine that you've met some alien species. They use a sort of hieroglyphic language. And all you know is one of these represents the word booba and one represents the Word Kiki. If you just had to guess, which one do you think is which? And one of them is this very spiky shape and one is this more organic round shape and it is like universal like 99% of people, language independent are going to say the sharp pointy one that's kiki

0:13:51 Thomas: Well, and you know what's interesting as a podcast editor, the waveform actually looks like that. I mean, it's not in that. Yeah, those sharper sounds like a you know like those kind of sounds are going to spike more whereas something that's like wow it will look more rounded

0:13:58 Jenessa: It does, doesn't it? Mhm, yeah Yeah. Uh -huh. It makes a big old wave, right?

0:14:10 Thomas: And it's like I know that that's not exactly the reason like we're not all imagining the waveform but at the same time kind of we are in a way like it is like like a like those kinds of sounds are going to seem more sharp than like a, whoa, you know? And it's like, this sounded like absolute nonsense, but also not like every, and what was the percentages on that? It was, it's pretty universal, right?

0:14:33 Jenessa: It's like 98, 99.

0:14:35 Thomas: There you go.

0:14:36 Jenessa: It's this isn't like a, well, you know, it tends to be like 54. No. No this is like, people feel strongly about this. And think about even like the mouth shape, like key, key, thin, long, and like, ah, this big big open mouth shape. It's visually and auditorily representing the object. And there is a proposal that this may have facilitated our language development. It is totally arbitrary, but if we all agree that the word fork, that right for that object.

0:14:39 Thomas: 60, 40. Yeah, right. Yeah yeah. Absolutely.

0:15:12 Jenessa: Spoon doesn't feel right for If we have an agreement, for some reason it just all feels right, we will have an easier time coming together and agreeing. And language is very, in a weak sense, synesthetic.

0:15:14 Thomas: It's so cool. Absolutely.

0:15:30 Jenessa: It different from strong synesthesia is this agreement. Agreement. Not, for me, middle C is blue, and for you, it's green. It is like, no, we agree. This is the correct sound for that word.

0:15:42 Thomas: That's so fascinating. I love that.

0:15:44 Jenessa: There is something going on there that seems like humans do gravitate towards a tendency to, you know, we are pattern generators and pattern -seeking, and we associate things, and it's a way to connect things conceptually. So one possibility is this is just that on overdrive.

0:16:08 Thomas: You would think if it were that there'd be more agreement, like a little more universal.

0:16:14 Jenessa: That would make more sense, wouldn't it? If there was some logical connection between them, then it would be the step in this drawing connections process would be, ah, yes, the letter A really, there's something red about the letter a, but there isn't. Right. It

0:16:29 Thomas: Or is it because of Apple? No, I don't know.

0:16:32 Jenessa: Make sense, wouldn't that the objects you encounter the most frequently in your life, but then, you people who more frequently encounter green apples would have some disagreement with you, right? So

0:16:41 Thomas: But at least there would be a reason, you know? There'd be like a, yeah.

0:16:44 Jenessa: Anything, any reason at all that's not completely arbitrary. But for the people who experience this, it's obviously not arbitrary.

0:16:52 Thomas: It's consistent to them, right? That's another thing about the actual synesthesia is it doesn't, yeah, yeah exactly.

0:16:53 Jenessa: Yes, extremely consistent. Yeah. There's a really good book, if people want to read more about this, called Born on a Blue Day. Written by Daniel Tammet, and he experiences synesthesia for, particular, his stuff is really associated to numbers. And he's also autistic, and he uses it to communicate in a lot of ways to use numbers for associations, and like his numbers have textures, and they have feelings to them. He also, there's a story in there about some um think it was twin girls who the mother comes in they're about five or six and they're arguing and she's like what are you yelling about and she was like well she says tuesday's green but tuesdays yellow and the mom is like tuesday does not have a color and now they're yelling at the mom because I may not agree what color tuesday is but it has a color damage. So, you the people who experience this experience it very and consistently.

0:17:47 Thomas: Mom yeah I imagine yeah yeah

0:17:55 Jenessa: Okay, kind of eliminated the, this is all made up, this is just a metaphor. This is a literal sensory experience. So how can it be happening on a a low level sensory phenomenon, it can't be that a sound is triggering your retina. There's just no mechanism for that. And when we know there is an extent to which it's context dependent.

0:18:20 Thomas: That's what's blowing my mind I really cannot get to the bottom of how sometimes the context matters and it seems like it's got to be at a higher level of your brain and then other times it's like so quick that it'll you color test thing that we talked about was super fast it seems hard to imagine both those things are true true

0:18:38 Jenessa: Right. So to kind of get this to make a little bit of sense, kind of like how we did the other day crash course how is sensory perception a little bit of like crash course what is a brain um yeah no big deal

0:18:52 Thomas: That should be easy yeah well it's a pile of meat that shocked we a little bit that has shocks in it that uh dreams I don't know all

0:18:59 Jenessa: You're not wrong um so basically yeah if you want to think of it like an input output machine and if you think about these brain areas like have a a certain output that to create this output, and then they receive certain inputs. Say I'm a brain area that the thing I output is, this is color, or this is a face, or there's a moving object over there. Can see how different types of sensory information are more or less useful. So brain area I was focused on in my dissertation does moving objects in the periphery. That one's a lot less picky. Sound or visuals, or ideally both, are really good for like, where is this thing? And I don't really care what it is. Some other brain area can bother with that problem. But where isthis moving object? Auditory and visual are really good for that. So I'm not picky. I'll take it. An area that does, this is a green object. It's got to be kind of picky about like, I don't know what, what other thing than vision is that really going to do?

0:20:18 Jenessa: So as you're a little baby developing and you come into this world with this this pre -built system. It has some general expectations of what it's going to get. But on the other hand, it's this extremely flexible organ, plastic, plasticity. It is going to take what it gets in its environment and change. So if you never get exposed to this thing, but you do get exposed with this other thing and it adapts and it changes and it makes it work. Work, and you're more flexible as a kid, but you're still very flexible as an adult, you'll find ways. It's still not fully understood, but we think what's going on is a lot of things are heavily connected as a baby with some of the roots and the really, in particular, the type of output predetermined, but what the input is going to be is not so predeterminated. And so there's a lot of connections. And then you just, you prune them back as you discover that they're not so useful anymore. So there's burst in the synapses, synaptogenesis, it's called the synapse is being the connections between neurons. And we're going to cut them back when when we discover that one's not helping. Dogs do bark. Dogs are not connected to apples in any particular way. So we'll trim that off. Not that you have like a dog neuron and an apple neuron, but you know, metaphorically speaking.

0:20:18 Thomas: Right yeah I'm on pc neuron no I'm just kidding the apple neuron is that hasn't come out yet but I will own one as soon as I can and it'll be way overpriced

0:22:03 Jenessa: So yeah. You've got your brain and it's, a it's big old lump of meat and we have not injected apple into it yet. And we're starting to connect things up and prune them back. And if you've, going according to plan brain wise and in your environment and your sensory receptors, everything is typical, normal, whatever. We We, kind of know how your brain is going to end up. Your visual stuff is going to be over here. Your auditory stuff is gonna be over here. There's gonna be some sensory integration areas, yada yada. Anything about your sensory experience is atypical or your brain is atypical, things are gonna get rewired and repurposed and behave differently. It'll do what it's got to do. That's fine. But let's imagine instead something happened to the pruning process and for for whatever reason, a connection between two things that are not actually related just didn't get pruned. Is basically the theory we're working from right now. You should have learned that objects have colors. Apples can be red and green, and dogs can be white and black and brown, and all these kind of things. But musical pitches, sounds, all the sounds, they have colors. So we'll cut the connection between those two areas. And for some reason, some people just didn't.

0:23:38 Jenessa: Have yet to hear a good explanation. Know, there was one group that proposed, well, it could be about proximity, that like the the area in your brain that processes color and the area that processes graphemes, letters and numbers, they are extremely close together. It would kind of make sense that that's the most common form of synesthesia. They're right next door and they stayed so they just didn't detach. But then if you think, well, then somebody with color pitch, when the part of the brain that processes pitch and the part that processes color are much further apart so why wouldn't everybody with color pitch also have color grapheme like that they don't so I'm not sold on that explanation um that gets proposed right okay maybe maybe some people just didn't prune as effectively. But it can't be that you just didn't prune your whole brain, because then that's inefficient brain. That's like a brain that never matured. That would be not good. Is a good thing to cut useless connections in your brain. Why did it selectively just not prune this one thing? I donít know. Childhood experience, probably. Probably something just,

0:24:01 Thomas: Interesting interesting really

0:24:54 Jenessa: Right,

0:24:55 Thomas: So do we have any indication of when synesthesia starts I guess it's like with everything with kids it's hard to know to because they can't communicate it right away but oh

0:25:04 Jenessa: And parents probably ignore it when kids say, I mean, kids say weird stuff all the time, right? Like, this is Susie, and you're like, cool, nobody's there, whatever, we're moving along, like, so, mom, the pancakes are purple, and your 'e like, alright, whatever. Like, sure.

0:25:07 Thomas: Fair yep they sure do the walls do have demonic voices sure kid yeah no I'm just kidding

0:25:27 Jenessa: I have places to be and I can't put your socks on, please. Like you just you don't have time for this.

0:25:33 Thomas: Ignore the screams yeah oh

0:25:35 Jenessa: Yeah. So, you know, it traditional definition of strong synesthesia is you are born with this or it develops so very, very early in life, so early that you you don't remember a time when you didn't have it. Then again, on the other hand, we have examples of acquired and adult synesthesia.

0:25:58 Thomas: Really oh but with like brain injury type stuff yeah that doesn't count no I'm just kidding sure

0:26:01 Jenessa: Of, yeah. So I'm sure people are, well, it feels like it, right? So I am sure people recently research on lsd in humans has become legal in lab settings and in some of that recent research uh asking people like what are you experiencing do you feel this do you feel that the most commonly reported experience I think it was about 80 percent of participants it was audio visual synesthesia so sounds were making colors well

0:26:13 Thomas: Interesting so these babies are doing lsd that's what you're telling me that's

0:26:41 Jenessa: My hypothesis here is Is that this is a serotonergic network overactivation, possibly.

0:26:49 Thomas: Yeah that's what I meant yes interesting

0:26:52 Jenessa: Essentially, yeah, that, like, babies are just, you know, they're all synesthetic. They're all bouncing off the wall, little hallucination machines. I don't know. Like, that there might be some hyperactivity in that serotonergic system. Because LSD is just, like super serotonin. It's hyperactivating that. But here's the thing, is if the only way to get the experience would be to have not physically pruned the connection, a drug in an adult shouldn't be able to do this. So the connection has to still physically be there.

0:27:29 Thomas: Oh but it could be you ignore it like a lot of stuff that our brain just ignores

0:27:34 Jenessa: Yeah, exactly. The hypothesis is an unmasking. That you are constantly masking. Masking, you've maintained physical connections that you don't use frequently, but that you occasionally need to pull up. So we keep them suppressed, but we don't cut them away permanently. And when you need it, we're going to unmask and let it out. And LSD is going to do that. Serotonergic drugs are going to be used.

0:28:04 Thomas: Like a plan let's do it oh no you weren't talking Yeah, I gotcha.

0:28:06 Jenessa: We're not going to let it go. Past character and fitness. Don't, don't do drugs. That's, that's my official advice. Thank you.

0:28:12 Thomas: Don't do drugs? Oh, okay. I was hearing a different message, but I guess I would. That was my synesthesia. My synesthesion adds a drug -related message to sounds.

0:28:25 Jenessa: Oh God. Um, so the other one we have that kind of fits with this is examples of acquired synesthesia. So example, um, mean, these are all case studies, but a patient who never had synesthesia before loses his vision and he starts learning braille as many not all but many blind people do and he finds that when he touches the braille bumps he's getting flashes of color and he has a really significant blindness this is not vision hitting his retina um they did all kinds of testing to you know basically to eliminate the making it up type explanations or that it's random. And it seemed pretty clear he was essentially developing a form of color grapheme synesthesia.

0:28:55 Thomas: That's interesting. Interesting.

0:29:16 Jenessa: It was touching the letters. It was not touching random objects. It Was beginning to be associated with the letter. That seemed to be the the most commonly documented was for amputees. So pretty much every amputee is going to develop phantom limb sensation. It's extremely common. If you're lucky, you will get the sensations pain. And that will tend to, not everybody, it will tend to go away within like two or three years um yeah if there's pain associated

0:29:46 Thomas: Or three years? Wow. I guess I'm pretty damn used to these limbs.

0:29:53 Jenessa: Yeah your brain likes your limbs a lot if you have pain associated with your phantom sensation um could go on for decades it pretty much yeah it pain yeah there are people who just it's it's bad it's really bad and we're working on treatments but I

0:30:01 Thomas: Then your brain hates you. Decades? What? Come on, man. Haven't Haven't these people been through enough? Like, what the hell? Unreal.

0:30:12 Jenessa: Know it's so terrible like you lose a limb that's already so traumatic and then it's limb is gone and it's you're feeling physical pain of a limb that's not even there.

0:30:24 Thomas: Why couldn't that have been reversed, you know? Like... Give me a break. Like, the non -pain kind lasts forever, and the pain kind lasts like a day. Come on. It must be that all -loving god of ours oh

0:30:34 Jenessa: I yeah. Course, right? Like, oh, God, it's so terrible. And, you know, it is why, like, when we do find treatments for that, have you, are you familiar with the mirror box treatments?

0:30:44 Thomas: Yeah I think so where it's like it makes you think you have like a limb that you don't for a second then yeah I didn't know it was treatment maybe but I I'm familiar with just the experiments that like you it strongly makes your brain think that you it is your limb and it's not

0:30:57 Jenessa: Yeah, and it can work for this. So for example one of the most common phantom limb pains for an upper limb amputee can be a sensation that your fist is clenched really tight and like nails digging into your palms and like just a muscle tension of that. So what they'll have you do is take the other limb that you still have, clench it real tight, just like that, put it into this mirror box and look at the mirror. So it'll give you the impression that your absent limb is there. And now just real slow unclench that fist while you're looking at the mirror. Instant relief.

0:31:32 Jenessa: And this can be people who've experienced decades of pain just short.

0:31:33 Thomas: But is there some danger that that well I guess getting rid of the pain is obviously the priority but is There's some sense in which like maybe that will prolong the sense of having having a limb you don't or something you know very interesting yeah

0:31:42 Jenessa: I share that concern. CERN. So I don't want to sound too braggy, but I swear this is true. I had the hypothesis for the longest time that, know, people were trying like pain medications, they were trying anti -seizure drugs that would prevent brain plasticity in these areas because they think the plasticity is what's causing it and remapping is what causing it. And I was like, I think you need to get out the other end of the plastic city. I think it needs to finish. So I was like I think lsd is what would do it I know mean in a medical supervised setting yesterday

0:32:16 Thomas: Like jenessa stop suggesting lsd to everybody that's hey do some lsb about it there

0:32:26 Jenessa: Literally was double checking getting ready for this and I found one of the most famous authors on this is giving psilocybin to amputees and it's working on this so uh called it I can't prove it.

0:32:35 Thomas: You go well it yeah you called it congrats I will go ahead and believe you um it does seem like what's happening here the phantom limb stuff and now you know it's is an an analogy, it's almost like, what's a good analogy? I mean, your brain is trying to get the input signals that it's always had and going to start like really, it is like if you are trying to hear something and it gets fainter and fainther, you are going to start listening harder and you are goign to start, oh, was that little tiny sound? Even though normally it should be, I am sure, a really strong signal, like you should get a pretty clear unambiguous nerve signal, I'm guessing, from just at vague level and it should be pretty strong, but then your brain's like, wait a minute, where, you know, it's it's gotta tune the dial a little bit. Like it's like it'S scanning the radio and it's turning the volume way up or something.

0:33:25 Jenessa: No, literally. Yes, yes. When we talk about attention, as talk about it as turning up the gain, that when you are trying to pay attention to something, you turn up the sensitivity of that neuron. And what that means is you'll be both more sensitive to the real stimulus, but you will also be more sensitive to random noise.

0:33:46 Thomas: Just noise. Yeah.

0:33:48 Jenessa: Exactly. So really what seems to be happening here is you get these overactive neurons that are just looking for something because it's not getting its normal input. And it's like, where is my input? And is the theory that I've been working on for of, seems like you lose the sensation, you hallucinate in it because there's this hyperactivity there's just bursts of activity going on and it's random activity because it's just hunting for something and then it seems to eventually settle back down into non -random activity driven by other types of sensory input so in this case you would typically see the area that used to represent that upper limb will eventually come to be represented by parts of the face will take that over the touch sensation and the motor.

0:34:26 Thomas: Interesting. Oh, wow. Wait, I didn't. So really, so like the, oh, No. So you're saying like it's almost like your arm, for example, you lose an arm, whatever. It's like you're another part of your body starts kind of being the input that that was.

0:34:52 Jenessa: Into that area of the brain. Yeah.

0:34:54 Thomas: Huh. What does that feel like to these folks?

0:34:57 Jenessa: So it can start with, and this is pretty common as a referred sensation of you touch on on the lip and they'll say, okay, I, this is not delusion. I am well aware you are touching my lip, but also, uh, you are definitely touching my thumb on my limb that I understand. I do not have that limb, but I can feel you touching my tongue. Then you touch the chin and they say, that's my pinky.

0:35:15 Thomas: Interesting. Huh.

0:35:21 Jenessa: And it's, it's starting to map to that location.

0:35:24 Thomas: So to your point, you do you you need that plasticity to remap maybe or at least to change in some way so that it stops looking for that same old input.

0:35:36 Jenessa: Yeah. And that's how I usually think of it is it's going to take time. But as it finishes that process, that seems to be why for all of these types of sensory loss, there's this onset and offset. Offset, it seems to be the timeline for that process. That timeline part, that's my, you theory on it. But

0:35:59 Thomas: While we're theorizing, it also seems like what would help is to try to do something that would develop senses in some other way. Because if we learn a new instrument, for example, where we kind of, I think maybe even you and I have talked about stuff like this before, when you're just learning maybe anything new that involves the of senses that we're talking about, you're going to develop more detailed sense in your fingers or something. So I wonder if that's a thought about a way to try to activate that remapping is find some way to try something new or practice something new that would make use of those

0:36:36 Jenessa: Yeah, I think that makes total sense. So like, exactly like you're talking about, If you learn to play the violin, for example, the fingers that you use to touch the strings, the representation that those get in the sensory and motor cortex in the brain will get larger. It will take up more space in your brain because

0:36:58 Thomas: I think we did talk about this because there's different areas like the this part of your back that's like the least sensed area of everybody usually. Yeah, that's right. A real gerrymandered house district, I thing is probably the joke I would have made hmm

0:37:10 Jenessa: Exactly. So essentially, that's what we see happening is if everything's going according to plan and we don't have this like pain interference because pain insists on being felt. Pain is extremely difficult to ignore. You know, as you can train yourself to do other things, you that is what the brain changing is. Right. Like learning is your brain changing. So, you know, these things go hand in hand, literally. And so of the things that's very interesting, we get these patients, right, they lose a limb and they get phantom limb sensations. And so, you know, the doctor anyway, because they've lost a limb. And that's usually requires some medical intervention. They're often reporting the phantom limb. And it took the longest time. But there was a doctor who happened to also be a researcher who studies this. And in talking to patients, had a patient say, Doc, you know, it's funny. Every time somebody else puts their arm up, I feel my phantom go up. And this person.

0:37:24 Thomas: Gotcha sure they actually refer to it as their phantom this is that is wow I didn't think about that interesting

0:38:22 Jenessa: Yeah. So the light bulb kicks on. I'm sure a thousand patients have said this before, but the lightbulb kicks on because this researcher knows that's mirror synesthesia. I have heard people with all their limbs describe that to me, the sensation of when that person's hand gets touched, I feel my hand get touched. And so they started studying it And it was something like 30 or 40 percent of their amputees with phantom sensation also had mirror sensation and not their whole body.

0:38:55 Thomas: Is the kind of thing where again they're looking so the brain is looking so hard for those inputs it's like gonna take anything interesting

0:39:02 Jenessa: Yeah. Yeah. Basically. So, so not the rest of their body. Right. I have my left arm and I see you get touched. I don't feel anything in my left arm, but you start doing stuff with your right arm and my phantom right arm is going nuts. I feel it moving. I feel like getting touched.

0:39:18 Thomas: That's wow so in that radio dial that's like again turned up to try to sense anything the visual of seeing something even if it's not yours the brain's like well that's something that's like that's kind of involving that limb we're gonna god this is all impossible never mind it shows canceled brains are impossible I do this I do several times an episode with you canceled it's not real, everybody, this is a big dream, none of us are real, yeah oh it makes perfect sense

0:39:40 Jenessa: Well, and I know. But it's, it fits, it fits with so many things because there is that that, you know, we always talk about senses as like, you know, there's color vision and then there's this and there's, you know, there's this, you know, that, and the other thing. But we don't usually talk about this broad sense of proprioception, your perception of your body in space and where you are. That is an integration of visual, of touch, of stretch.

0:40:13 Thomas: It's going to be a lot of things. Yeah.

0:40:15 Jenessa: You know where your limb is using the integration of so many any senses. So it's, in some ways, it's not surprising that without any touch or stretch receptor, visual is still kind of making your brain think a limb is there. And that there's a brain area that's still getting other sensory inputs. So, it is like, well, I know I don't feel a stretch receptor in my muscle anymore, but like, there could still be something there, right? Right. And when you learn to you're moving your hand around, right, you're learning to catch a ball, you learn in hand eye coordination. When you pick up a hammer and it extends the length of your arm, we can see in real time how your brain will adapt to perceive your arm as longer. Longer you learn to use objects you brain treats the object you're holding as if it's like part of your body in a lot of ways and will extend your understanding of how to move the object as if it's a part of Your Own Limb so it kind of all fits that like yeah I'm looking for So there's something going on there where our brains want to make connections. They're looking for something. We have a system to make connections. Even as an adult, if something goes wrong, I, you know, let's say I lose my vision. I've got this visual cortex that's not doing anything yet. You take away the mask, the thing that was pushing the activity down and saying like you have a job to do, do your job. It just starts firing like crazy. And so I start hallucinating. And in this case, we'd call it Charles Bonet syndrome is this visual hallucination process.

0:41:23 Thomas: The hammer fits. Jeez, what did JonBenet's parents do this time?

0:42:09 Jenessa: Oh, do you know what's so funny? Charles Bonnet, he documented this back in like, I don't know, 1700s, um, his grandfather went blind and started to visually hallucinate, and then he went blind and started to visually hallucinate, this coincidence um

0:42:26 Thomas: Is it a coincidence or?

0:42:28 Jenessa: Who knows honestly it's all a mystery really but as it's calming down a new process has come in and now that visual cortex is doing touch and it's doing auditory and And it's obviously not visual anymore. And I shouldn't even call it visual anymore So it seems like there is a mechanism in your brain To preserve structural connections That don't make sense right now will keep it masked And if I need it later, I will unmask it And that is how I stay flexible And that's how I'm the only species that lives on every continent Except the South Pole, I guess, or whatever um if you were to not only not prune it but not mask it you could end up with this sort of blending of your senses why did this exact connection not get cut and not get suppressed in this person and in this way no clue no idea no answers for that one is a mystery still mm

0:43:33 Thomas: Very interesting. It goes with a lot of stuff we've talked. I think we've talked about before too. And just in general, I feel like a lot of childhood development is more about perceiving less in a way is my impression or at least um perceiving less like when you're a kid everything is like the same volume like everything everywhere it's all it's very adhd and that's why kids I feel like kids are even non -adhd kids are more adhd than adults, I think, and it's like, it's an adult is boringly about like refining what you actually pay attention to and it feels like this is maybe maybe it sounds like what you're saying is maybe these cross cross connections are possibly a little more common than we might think. It's just, we don't, we aren't paying attention to them. And I don't think it's like something you could just turn off and on, obviously. Like it, it seems like it takes something significant to maybe change that and almost never changes.

0:44:26 Jenessa: So when we think about like a higher order cognitive thing kind of the whole point of that is those those are choices you make those are things you decide to do or not do when we're talking about sensory things um are kind of inherently involuntary you can pay more or less attention to sensory stimuli. But, you fact that the receptors in my skin picked something up is not really, that's not a choice, right? And so that's the level on which synesthesia is occurring. People can choose to pay attention to it and choose to use it, but it's still happening to them.

0:45:01 Thomas: Well, but at the same time, I thought we said it was like definitely some amount higher than that. Right?

0:45:06 Jenessa: Yes. So it's definitely above the receptor, But it's definitely below the level of needing to have completely identified it consciously. So you don't have to pull out a, you know, detector and know that that's middle C and read it on the screen and then it turns blue. It turns blue and you're like, oh, I later learned that's middle C. Now I know. So it's got to be happening after the receptor because receptor couldn't possibly do that by just physics. But it's got to be happening before the actual conscious identification and then decision making process. So it's somewhere in the middle there. And it might be some of these are more complex than others and therefore happening higher up in the system. But it's thing, the definitional thing will be the involuntary nature of it. There's something about this system that is just getting triggered as if it's sensory. So actually, I think coming back to the peripheral vision example with how would have like, okay, the number five in my central vision, it's green. We're going to move it out to your periphery. And it's, oh,

0:46:25 Thomas: That's the one that was so crazy. Yeah! Yeah. Sorry, just as you still see it, but it's black and white. I should have let you finish up.

0:46:27 Jenessa: I Yes, now it has turned to black and white as expected. Detected um one way to think of it would be this there's that five in my central vision now it does not have a color so it doesn't matter that it's hitting the cones in the center of my retina and I move it out and now it's heading the rods in my periphery but if it's getting processed in parts of my brain that are capable of processing color because they're receiving inputs from central vision, then it's capable of being green. But if I keep moving it into the periphery, and eventually I move that digit into getting processed in parts of my brain that only process peripheral vision,

0:47:14 Thomas: The big reveal. You genius. I was like, there's no way you can explain this fucking thing. Wow.

0:47:18 Jenessa: I the explanation, is now it has entered the visual stream that is predominantly peripheral, which ignores color.

0:47:30 Thomas: My gosh, yeah, so it's like, and importantly, just to make sure everyone understands, it's not that it's doing that physically, like in terms of your rods and cones and that crap, right? It's not like that, but in terms, it sounds like maybe in terms of efficiency maybe our brains are like well we know when something is in this area we don't even bother with the processing power of color essentially and so it's it's moved to a region that's only like perceptually only black and white in some way that's not just by the the actual rods and cones right

0:48:01 Jenessa: Yeah, that part of my visual field does not get sent to the color area. It doesn't trigger the color area.

0:48:09 Thomas: It's almost like, okay, so it's almost like you've got, think of our, our vision is like monitors, like TVs, like monitors. And you have the color one in the center and the peripheral is a black and white TV, but it's also, there's more than just the input. So you could have a color signal that goes into a black -and -white TV. It's still going to be black and White.

0:48:29 Jenessa: Exactly. It couldn't be color if it wanted to. Because

0:48:35 Thomas: So this is like, yeah, but the signal we're talking about is a little different, right? Because it's the synesthesia signal. So it's not a literal, So like it's still a color signal, but then your brain is like, well, now we're we're routing that to the black and white TV because it's always when it's vision, it's always black and White there. So we don't need it in the color TV.

0:48:53 Jenessa: You could almost think of it like as if normally the digit five for some reason is getting routed over to green but once it's far enough in the periphery nothing there ever gets routed to color period so it just doesn't it just skips that whole thing because a way to think of it um there in the physical world, these different sensory things are different. Sound One is a pressure wave. Color and other types of light are photons. Is physical pressure on your skin. Smell and taste are chemicals. But once it enters your, at the moment of translation, when it hits your sensory receptor, they're all just electrical impulses.

0:49:12 Thomas: Interesting. Yeah. Right. Right.

0:49:42 Jenessa: It's neuron fired or didn't. It is It's ones and zeros. So the only way your brain knows the difference between hearing it or seeing it or tasting it is based on what brain area it hit.

0:49:53 Thomas: Crazy.

0:49:54 Jenessa: It's all just electric.

0:49:56 Thomas: That's so cool. It's all electric. Like the Bob Dylan era. No, I don't know. Yeah. No, that I really, this is amazing because I really thought that was going to be so hard to explain how that would all be consistent with the kind of the theory, but that makes perfect sense. And that's, that's really cool. Wow. Is that a good place to leave it?

0:50:16 Jenessa: Me throw you one more thing as we leave off. You know, I always think about this when I'm teaching about these different types of sensory adaptations, interpretations, you know, I can tell people all about how like a person who becomes blind like look at this amazing echolocation ability you know they're like going for a hike in the dark and it doesn't even matter you and I couldn't do that I'd get lost but doesn't make a difference to them you know look at all these cool things they're doing and people be amazed but not like I want to be blind um and you know we can talk about the same things with like uh the amazing amazing peripheral visual abilities that deaf people have. And that can be super cool, but nobody's like, I want to be deaf. But, um, think a lot of times people hear about synesthesia and they're like, that's, it feels like an, yeah, it sounds like an addition. Right. So I just want to throw out the, like, why does that feel different? And a little flavor of like, it's not always super positive.

0:50:59 Thomas: I want that. Yeah. Yeah. Hmm.

0:51:11 Jenessa: Um, for some examples I found of, um,, somebody talking about, a person who has color pitch and they were driving and their friend turned the radio on and yeah all the colors it

0:51:24 Thomas: Yeah. Where in your visual field? I didn't even think about that. Where do they see it? Is it related to the sound source or is it just in there somewhere in their field of vision?

0:51:32 Jenessa: Depends on the person so some people would kind of more experience it like in the mind's eye um and it wouldn't be as obtrusive but some people experience it projected out into their environment and it will obstruct their vision so somebody talking talking about it, I've almost gotten in car accidents when friends put in their music and turn it way up.

0:51:56 Jenessa: So I can't imagine going for a long drive with no music. I'll lose my mind. One woman who, has mirror touch synesthesia.

0:52:04 Thomas: Well, there's podcasts, but yeah, sure.

0:52:06 Jenessa: Yeah, lifesaver, right? This woman has mirror-touch synesthesia, and she first noticed it as a kid when she was at a party, and there was a guy who got home from he'd been away for a long time and he's walking around everybody's hugging him and she says people were hugging him like they hadn't seen him in a while I remember feeling like I was being hugged watching him it was just so nice but then she also talks about she can't eat dinner with yeah she can't eat dinner with her family, it feels like they're shoving food in my mouth and I'm trying to eat and they're shoving their forks in my And it's like this thing piled on top of itself.

0:52:34 Thomas: In the face and oh okay oh oof yikes wow I guess he blindfolded or something oh

0:52:50 Jenessa: Yeah. And there was another time she was trying to help this kid. Backward and hit his head just smack. And I went to run and all of a sudden my eyes went blurry and I was down on my knees on this thing before I could get to this kid and I'm like, this child, he needs help. My head hurts so bad. I was crawling to get to him. So so pleasant um for some people um know obviously we talked about our derrick tastes of earwax it's a little hard to be buddies um there's another woman where numbers have spatial locations um

0:53:21 Thomas: That must be really hard to take a test or something yeah

0:53:32 Jenessa: It messes with arithmetic operations so subtraction and division were were much more difficult across the parts of the number time, line that were kind of bent. So like if seven and two were closer together, which for you and I are obviously separated by precisely five digits, that made it harder for her to do subtractions. So I always think it's interesting to throw that out there of like, it feels like an addition of an ability, But is this a disability? I don't know.

0:54:01 Thomas: Hmm I don't know I guess that's depends on if it's yeah causing problems for how you function but it does seem like it could be either. Could be an extra ability, could potentially be a disability. That just all depends on your luck, I guess.

0:54:17 Jenessa: It's something to think about as you think through these things. It's definitely when I've taught like disability culture classes, I always love throwing this one in there of like, what do we think of this one? Um because it feels so additive um yeah synesthesia it's a weird world and we don't really have an explanation for it but it seems pretty pretty interesting yeah

0:54:42 Thomas: Well, that is so fascinating. That was a delight. Jenessa, thank you so much as always. And do have another plug? Got way for us to not fuck up voting?

0:54:52 Jenessa: Um so there are voting helplines that you can check out oh my gosh I wish I remembered remembered, the name of one right this second would be super helpful. Oh, think it's just called election hotline, election help hotline. Oh my God. If you Google it, you're going to find it. This is embarrassing. But if you run into an election emergency the day of, like while you're trying to vote, you can call any of, there's multiple, but you can Call Those Resources. Resources um please also document if you run into problems while you're trying to vote because you can report this afterwards and do something about it you're not just stuck with whatever happened um that's my whole job is reporting that stuff so uh yeah write it down if something happens uh who what when where why I'll

0:55:43 Thomas: So if Trump wins, I am reporting it. Yeah. Hi, election emergency. We're fucked.

0:55:50 Jenessa: No oh god I'm just not thinking about it two gonna be fine everything's fine yeah

0:55:58 Thomas: Right. Well, this was amazing. This was so much fun. Jenessa, thank you very much.

0:56:03 Jenessa: Thanks for having me familiar with um booba kiki experiment okay

0:56:28 Thomas: All right now you're just making shit up.

0:56:31 Thomas: Jenessa, stop suggesting LSD to everybody, that's it, show's canceled, brains are impossible, I