Charan Ranganath

Traumatic brain injury is another one of the big risk factors.

Traumatic brain injury is another one of the big risk factors.

Traumatic brain injury is another one of the big risk factors.

Well, it's not fully understood, but I'll give you my best guess that's science-based and not just my wildly speculating completely. But basically, one of the early findings that gave you a sense about what deja vu is, is Hewlings-Jackson, who's this great neurologist who did pioneering work in behavioral neurology.

Well, it's not fully understood, but I'll give you my best guess that's science-based and not just my wildly speculating completely. But basically, one of the early findings that gave you a sense about what deja vu is, is Hewlings-Jackson, who's this great neurologist who did pioneering work in behavioral neurology.

Well, it's not fully understood, but I'll give you my best guess that's science-based and not just my wildly speculating completely. But basically, one of the early findings that gave you a sense about what deja vu is, is Hewlings-Jackson, who's this great neurologist who did pioneering work in behavioral neurology.

observed that many patients who get epilepsy would have this aura, it's this mental sensations right before a seizure, where they would get an intense feeling of deja vu. It doesn't happen in everyone, but a certain number. And this is associated with temporal lobe epilepsy. And the hippocampus, as you know, is in the temporal lobe.

observed that many patients who get epilepsy would have this aura, it's this mental sensations right before a seizure, where they would get an intense feeling of deja vu. It doesn't happen in everyone, but a certain number. And this is associated with temporal lobe epilepsy. And the hippocampus, as you know, is in the temporal lobe.

observed that many patients who get epilepsy would have this aura, it's this mental sensations right before a seizure, where they would get an intense feeling of deja vu. It doesn't happen in everyone, but a certain number. And this is associated with temporal lobe epilepsy. And the hippocampus, as you know, is in the temporal lobe.

But there's also these areas around it that are super important for memory, including the amygdala, but also really the perironal cortex is a key, key player in this. And so the... So then you have Wilder Penfield and other people who started to do these surgeries for epilepsy and they said, well, I want to make sure I'm not taking out good brain, right?

But there's also these areas around it that are super important for memory, including the amygdala, but also really the perironal cortex is a key, key player in this. And so the... So then you have Wilder Penfield and other people who started to do these surgeries for epilepsy and they said, well, I want to make sure I'm not taking out good brain, right?

But there's also these areas around it that are super important for memory, including the amygdala, but also really the perironal cortex is a key, key player in this. And so the... So then you have Wilder Penfield and other people who started to do these surgeries for epilepsy and they said, well, I want to make sure I'm not taking out good brain, right?

So Penfield wasn't responsible for HM and that was like kind of an irresponsible surgery.

So Penfield wasn't responsible for HM and that was like kind of an irresponsible surgery.

So Penfield wasn't responsible for HM and that was like kind of an irresponsible surgery.

Yeah. And so, in fact, he had this dense, dense amnesia, right? And actually one of the little known things even in memory research is he actually lost – he had what's called a temporal lobectomy where they just hack off the front part of the temporal lobe. It might have been cauterized. I can't remember the – I think he cauterized it.

Yeah. And so, in fact, he had this dense, dense amnesia, right? And actually one of the little known things even in memory research is he actually lost – he had what's called a temporal lobectomy where they just hack off the front part of the temporal lobe. It might have been cauterized. I can't remember the – I think he cauterized it.

Yeah. And so, in fact, he had this dense, dense amnesia, right? And actually one of the little known things even in memory research is he actually lost – he had what's called a temporal lobectomy where they just hack off the front part of the temporal lobe. It might have been cauterized. I can't remember the – I think he cauterized it.

But anyway, they do that temporal lobectomy and he actually had the posterior one-third of his hippocampus. But he had lost his perirhinal cortex bilaterally. And that turned out to be Betsy Murray at NIH later and other people turned out to be a huge thing. So one of the reasons I think that he became so densely amnestic is that it was bilateral.

But anyway, they do that temporal lobectomy and he actually had the posterior one-third of his hippocampus. But he had lost his perirhinal cortex bilaterally. And that turned out to be Betsy Murray at NIH later and other people turned out to be a huge thing. So one of the reasons I think that he became so densely amnestic is that it was bilateral.