This is the interview with V.S. Ramachandran from episode 003 of the You Are Not So Smart Podcast.

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One of the leading neuroscientists in our era, maybe the leading neuroscientist, V.S. Ramachandran has written extensively about phantom limbs and paralysis as well as the confabulations often conjured by those who experience such problems. His research includes everything from mirror neurons to synesthesia, and you can find dozens of his fascinating lectures online. He is the director of the University of San Diego’s Center for Brain and Cognition, and he is the author of The Tell-Tale Brain and co-author of Phantoms in the Brain.

 

Ramachandran:     So, if you have right parietal lobe damage, the right parietal lobe is where you represent your body, construct your body image, so you get different sensory inputs from the hands and muscles and joints and from your eyes and from hearing all converging on the right parietal lobe.

If you close your eyes and stand up, you have a vivid image of your own body in space and time, it’s called your body image, and if you open your eyes, it confirms your hand is here and it’s moving, or whatever. That dynamic internal image of your body is called your body image. In these people, when the right parietal is damaged and the left arm is paralyzed completely, they will: A – they will deny the paralysis, and B – they will even deny the ownership of the arm, because it is a disturbance in body image.

It leads them to say, “this arm does not belong to me, it belongs to your mother, it belongs to my mother, or it belongs to my brother.”

And I’ll say, “where is your mother?” They will say, “she is hiding under the table.” This is a person who is mentally perfectly lucid and intelligent, claiming that their paralyzed lifeless arm belongs to somebody else.

David:     Do you see a lot of that sort of confabulating about different brain issues, not just in denying that you have paralysis, but I’ve read about Korsakoff’s Syndrome and Capgras; how are they related?

Ramachandran:     Yes, in Korsakoff’s amnesia, often seen after chronic alcoholism, the person does damage to the hippocampus, but he also can do additional frontal damage as well.

You need that for the patient to start denying his memories. The profound loss of memories, they can’t form any new memories, the patient comes and talks to you for ten minutes, for the first time, you introduce yourself and chat with them for ten minutes, you leave the room for five minutes to go to the restroom and come back, he acts like he’s never seen you before.

Because there is very profound anterograde amnesia, and yet he is not aware of his problem. This whole disorder is called Anosognosia, denial of illness, lack of awareness of illness.

David:     Could you help me, and others who will listen to this understand, what is the motivation for and the mechanism of that explaining, that need to have a narrative for what’s going on, if you don’t understand it?

Ramachandran:     Well, I like to compare it with a military general, who is receiving different sources of information while preparing for battle.

So he is preparing to launch battle at 6am in the morning, and at 5:55, he’s got all the generals lined up and all the scouts have brought him information, and he’s going to launch battle at dawn, at 6 a.m. exactly.

Suddenly, one chap comes along and says, “This is wrong, we’ve seen the enemy is actually six hundred times, not five hundred. We were misinformed.” What you do is, you say, “shut up.” You don’t revise all your battle plans, it would be too costly. What’s the likelihood that this one guy is right, and everybody else is wrong? Let me just ignore what he is saying. This is what we call denial. The tendency to not accept information that’s contrary to your sense of narrative.

But, if that chap comes and says, “they’ve got nuclear weapons, I’ve just looked through the telescope, and they’ve got nuclear weapons.” Then you would be foolish to launch war, you have to say no, let me change my paradigm, let me shift gears.

So, there’s always a push-pull antagonism within the desire to preserve stability of behavior. So, it’s all about creating a consistent belief system, which you cling to, because you don’t want to veer off in random directions. If you responded to any piece of anomalous information, overreact to it, you would quickly become unstable. To avoid that, to avoid falling apart, to avoid your behavior becoming unstable, you engage in all these denial mechanisms.

But on the other hand, you can’t overdo it. We think all these denial mechanisms, these Freudian denials, rationalization, confabulation, denial, repression, all of that, mainly occur in the left hemisphere of the brain. The right hemisphere is your devil’s advocate. If the denial becomes excessive, it kicks you in the butt and says, “look, you’re overdoing it; you better face up to reality.” But, what happens in Anosognosia, this syndrome with right parietal damage, you see that the arm is paralyzed, the left hemisphere patches it up and says, “don’t worry.”  The right hemisphere would ordinarily correct it and say, “look don’t be stupid, you are paralyzed.” That mechanism is messed up and so the guy denies the paralysis and denies that the arm belongs to him. But the sort of everyday denial we see all the time is not unique to patients, but it’s grotesquely amplified in these patients because of the damage to the right parietal.

David:     So, would it be true to say that sort of explaining to ourselves is always taking place?

Ramachandran:     Yes, exactly. The internal sense of narrative and preserving stability of narrative is done by the left hemisphere primarily, but not exclusively.