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Metamorphosis: At the push of a button, a familiar face becomes a strange one

Metamorphosis: At the push of a button, a familiar face becomes a strange one

What’s up with those rude characters you see coming down the hall every single day, and then - just as you get near enough for the standard, semiconscious exchange of glances that (for you, anyway) invariably leads to saying hello – they avert their eyes and walk past you as if you’re a perfect stranger?

It’s doubtful that they’re all suffering from out-and-out prosopagnosia, or face blindness, although as many as one in 40 people may have inherited some degree of it. (Famed auteur/scientist Oliver Sacks suffers from a bona fide, congenital case.) But no question that we differ in our ability to recognize faces. And that may have a lot to do with how things are going in a small, marijuana-cigarette-shaped brain structure that swells at the bottom of our  temporal lobes, according to Stanford neurologist Josef Parvizi, MD, PhD.

The fusiform gyrus has previously been linked to face recognition. But Parvizi, collaborating with Stanford neuropsychologist Kalanit Grill-Spector, PhD, has nailed it in a striking experiment made possible because of a courageous epilepsy patient named Ron Blackwell.

Blackwell, who’d had part of his skull temporarily removed so that electrodes could be placed at the surface of his brain to monitor his seizure, decided that while he was lying there more or less immobilized for a week, he might as well pass the time doing something for science. So, working with Blackwell, Parvizi used electrical brain stimulation (it’s completely painless) to prove that  the fusiform gyrus plays a key role in processing information about faces. As I wrote in my release about a paper on this study, just published in the Journal of Neuroscience:

[Parvizi] showed that mild electrical stimulation of two tiny sites in a 2- to 3-inch-long brain structure called the fusiform gyrus could cause the subject’s perception of faces to instantly become distorted while leaving his perception of other body parts and inanimate objects unchanged.

The push of a button enabling current to flow between those two spots caused the patient to immediately exclaim to Parvizi:  “You just turned into somebody else. Your face metamorphosed!” (Anyone who would like to watch Blackwell’s reaction in real time can view this publicly available video made while Parvizi was pressing the brain-bending buttons.)

I wouldn’t advise anyone to try this kind of thing on their friends, although with Halloween coming up it’s admittedly a temptation.

Previously: Researchers identify the neural structures associated with poor reading skills, Why memory and math don’t mix: They require opposing states of the same brain circuitry and Study suggests strength of brain’s neural pathways a key factor in intelligence 
Photo by jez.atkinson

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