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Tuesday, December 09, 2008

Consciousness: Pioneer neurosurgeon on a key question regarding our minds - double consciousness

A group of us were discussing the question of consciousness, and now American neurosurgeon Michael Egnor writes to remind me of the pioneer neurosurgeon Wilder Penfield (first neurosurgeon in Montreal) who, he notes, "started his career as a materialist, and he was a passionate dualist at the end of his career." That must have been when he wrote his book The Mystery of the Mind (Princeton University Press, 1978). Egnor tells me,


Penfield was a neurosurgeon who pioneered the field of epilepsy surgery. He operated on thousands of patients who were awake (under local anesthesia), and were able to speak to him while he stimulated various regions of their brains.

Penfield found that he could invoke all sorts of things- movements, sensations, memories. But in every instance (hundreds of thousands of individual stimulations- in different locations in each patient- during his career), the patients were aware that the stimulation was being done to them, but not by them. There was a part of the mind that was independent of brain stimulation and that constituted a part of subjective experience that Penfield was not able to manipulate with his surgery.

I've performed some epilepsy surgery (although it's not my primary specialty), and my experience has been the same. Patients always know that the memory or sensation or movement is is imposed on them, not by them. Some colleagues who do specialize in epilepsy surgery have confirmed Penfield's observations as well.

Penfield called this "double consciousness", meaning that there was a part of subjective experience that he could invoke or modify materially, and a different part that was immune to such manipulation.

There probably has been no other person who has had Penfield's volume of direct experience with stimulation of the brain during consciousness (he probably did at least 10,000 such operations, perhaps more. He was practically the only person in the world doing this work in the early and mid 20th century.) He was a meticulous scientist (not that common among neurosurgeons, who tend to be 'cowboys').

He considered the strict materialist view of the mind to be utter nonsense.
My favourite Penfield quote is,

"Brain surgery is a terrible profession. If I did not feel it will become different in my lifetime, I should hate it." (1921)
Penfield died in 1976, before the Decade of the Brain, when the fact that brains constantly change and are changed very often by minds started to become generally known. If neurosurgery did not "become different" in his lifetime, it certainly did soon after.

Related features:

Neuroplasticity: Growing recognition greets Canadian psychiatrist Norman Doidge's new book

More on Norman Doidge and the brain that changes itself

Psychiatrist Jeff Schwartz speaks on what drugs can do for you - and what you and your mind must do for yourself

It used to be all my mom-';s fault and now it's all my brain's fault? Naw!

Change your mind, change your brain - Smithsonian conference

Consciousness: A physicist on the recent New Scientist flap on non-materialist neuroscience

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