Rabbi when we think of breakthroughs in biology normally we think of the dna revolution these gigantic things but what you've done with phantom limbs has deep implications for how the brain works and it's just a like a radical new way of seeing things so what was the process what what's what is the point.
And and how can we use phantom limbs to understand how the brain works well basically the phenomenon involves my arm is amputated or lost in a car accident continue to continue to vividly feel the presence of the missing arm you call that a phantom.
Often excruciatingly painful can you help the patient to leave the pain so so the arm has been amputated either deliberately for disease or in injury and i and i i feel it's there but it i have it's painful your pain in the phantom very often not always but very often yeah one of the first things we did was.
Simply put a take a q-tip and did a routine neurology exam with a cotton bud and touch different parts of his body and face and what do you feel and remarkably he said well i feel that touch in my phantom thumb oh even though thumb was here and faces here yeah yeah and it's missing there's.
No arm there and he feels it in that in that thumb and touching the index finger pinky ball of the thumb there's a map of the face on the hand on the face now why does it happen it happens i think because the in the in the map of the surface of the body and surface of the brain.
Completely surface the body every point is mapped onto a specific point in the brain is what we call a penfield map right the body surface the so-called homogeneous homunculus yeah in that body it's map the hand is right next to the face so when you amputate the hand the hand area and the brain is hungry for new.
Sensory input so the sensory input from the face skin which normally innervates the face area adjacent phase area invades the vacated territory corresponding to the missing hand fooling the brain into thinking that the sensations are coming from the missing pan of hand wow.
No needed brain imaging to prove that this is going on this is relevance to phantom pain because there's miswiring during the rewiring you get you get pan and pain one of the outcomes of that yeah so a natural result of the plasticity of the brain which in some cases is very good if you have a stroke you can eventually recover through.
Plasticity here it's it's gone wrong gone wrong yeah except we landed on the trick of using a mirror which was widely known but i mentioned it briefly yeah the patient often says the phantom is awkward it is clenching my my fingers are clenching into the.
Palm producing extruded excruciating pain i cannot open my fist it didn't just locked that and it's very painful then you put your hand in front of this mirror the mirror box so you put this phantom on the left side of the mirror the shiny side of the mirror is facing me the physician.
Uh and the patient looks at the the the reflection of his normal hand in the in the mirror resurrecting optically his phantom hand when you say can you move your fingers to the normal hand right hand synchronously with the phantom and then clap or wave or something but symmetrically and.
It's really just the one hand being a mirror and he's seeing both that's he sees both right yeah and he can't really move his phantom he's already said that right he says oh my god it's unbelievable the movements have come back after 10 years my phantom is moving again the pain is going away the pain has been.
Haunting me for months and months and years it's gone away then it's close your eyes and it doesn't the pain comes back so i said i'm not going to get a price for getting somebody to move a phantom limb but if he practices for for a few weeks then the pain does go away in about one third to half the patient's.
Substantial reduction in pain using a mirror and nothing else now that's surprising in itself but what's even more surprising is patients with phantom men listen to this right you have a patient of the phantom limb and uh i i came across a paper by yakima.
Regionality and mirror neurons and then his colleagues and one of the things that's been discovered is if you touch somebody on the skin the sensory area in my cortex fires a neuron in my sensitivity map fires elbow another neuron so no no no no fire so okay that's fine well-known well-known physiology.
Now if i watch you being touched yeah different parts of your body that same neuron virus 10 of the neurons will fire if i'm watching another human being being touched this sounds like esp of course it's not my brain is creating a virtual reality simulation of the.
Of what's going on in your in your body so to speak and saying and empathizing saying this guy is being something's going to hit his face hit his body and he's going to experience the same thing i would experience if i were with my body in your head so you do a mind reading so to speak a sort of.
Virtual reality simulation of his his sensations and allows you to empathize with that person right okay so this is surprising in itself the neurons will fire somebody else right the same in the same area that if i if i'm doing it myself or i see you doing it correct same area yeah but only ten percent of.
The cells yeah yeah other cells are normal regular sounds right now the interesting thing is if i then say um why why then i don't feel the sensation if i watch it being touched same neuron is firing if i poke you with a needle i don't think i'll chip put it on my hand.
If i'm feeling everything that you're feeling the neurons are firing in the amygdala and anterior cingulate for pain pain sensations why don't i feel the pain you feel not merely empathize with it the answer is the skin around in your skin in your in your hand does not have pain signals.
It's not you sending a veto signal upstairs yeah shut up you're not in pain nobody's poking you empathize he's in pain this competition occurs very rapidly so i am emphasizing i don't feel the pain now what is the prediction from that yeah prediction from that is if you empty it in my hand.
I have a phantom then i watch it being poked in your hand then i should feel the pain in my family because there's no veto very simple hypothesis right 100 years 200 years of study in fact nobody had done that we had three patients sit down and we just took hasn't opened their eyes and said i'm.
Going to poke my hand and see what happens in your phantom for sure oh my god it's very strange doctor i experienced that pain in my my wrist that's very odd yeah and then i said how about that that's in my elbow i feel that pain so there's a that was a a prick to to yourself yes.
And i'm feeling it in my face you're feeling in your phantom yeah and this is extraordinary because dissolving the barrier between you and me yeah the notion of self and others this tenuous barium of skin and bones is dissolved by removing the arm and i start.
Experiencing your sensations now third question how do you help this patient i said go home and then whenever you feel the pain in your phantom you can't massage it because it's a phantom ask your wife to massage her hand watch it get a phantom massage to relieve the pain.
And guess what it does but we haven't done control trials yet so we don't know how prevalent it is tony yang and walter reed is doing some work on this but we hope it's very even even simpler in the mirror another person and this gives deep insight into the empathy and it's much broader than just.
The pure physiology of the phantoms exactly so it's not merely telling you about pharma pain but the whole concept of empathy including emotional empathy in fact we've seen patients with another group of patients not patient normal people who have what's called congenital inter-sensory fat sensei referral.
Sensations we call it congenital intuitive sensations it's also discovered by uh jamie ward in england and sarah blakemore what you see is otherwise completely normal no phantom nothing normal person experiences your sensation just don't come out and told people about it.
But she or he has had the entire entire life you call it interpersonal referral okay exciting thing if you tickle yourself yeah she starts giggling uncontrollable giggling and claudia sellers in our department has worked on this uncontrollable giggly she experiences and this patient experiences and she.
Can't stop oddly enough she can tickle herself you and i can't tickle ourselves yeah she can tickle herself because it's altered circuitry and she'll also say here's a very important point i want to make right if i may been testing patients people think.
You'll use sophisticated equipment months of research thousands of dollars you don't have to sometimes you do it but you don't have to here's the young lady telling me she feels if i do this she feels in her leg if i do this she feels it how do i know she's not making it up to draw attention so i said okay.
We have this two students sitting next to me she's telling me that anytime i touch the student she feels it or touching myself she feels it right did this i did this to a student hitting her face yeah yeah the student flinched the draw and she did the same thing no no no she didn't know you were going to do that she didn't know i was going to.
Do that yeah no normal person flinches and draws back blinker flight does not occur right you get a startle reflection you do that they don't do this telling me immediately you're dealing with a real phenomenon yeah secondly i said what if it's a lot cheaper than an.
Absolutely but secondly we do the simple thing you say what do you put your hand in hot water boiling water i put my hand on boiling water does she feel the heat yeah right so i said i'm going to do this he said no don't do that i said no don't worry i'm going to put it withdrawal quickly.
And i had a bucket of probably dry ice or something to make it look like it was boiling yeah i did that and she said i felt the wetness of the hand but no heat that's very strange you know and then i thought maybe the maps and the better sensitivity maps mirror neurons don't occur for.
For heat and warmth and cold they only occur with touch and pain right yeah we don't know why you have to do that the way the brain is wired right then i started talking to her and i noticed he was doing something here behind my banner back she's doing this you see now why is she.
Doing that because earlier i dipped my hand and then okay what it's still wet see she's still wet so she's doing that and then she's just wiping her hands and that tells me that you're dealing with it's like the dogs that did not bark in the night of the murder stories that.
Doesn't mean more than six months of brain emitting they've clinched the deal that is really a real phenomenon now we can study it and she's very empathetic hyperempathetic as you just pointed out so very interesting syndrome that we stumbled on.
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