Re: Question 34 Challenged

From: Harnad, Stevan (
Date: Sun May 25 1997 - 20:27:06 BST

> From: Leung, VWY
> About question 34, when a patient's brain is stimulated by the surgeon
> and the patient reports a memory, why is it an imagined episode from
> earlier in life? why is it not an re-experienced episode from earlier
> life instead....

For a long time it was described in textbooks as a kind of "recovered
episodic memory" for long-ago experiences. But as the Chapter in which
it is discussed says, when checked or followed-up they turned out to
be recombinations of bits and pieces of memory and imagination, not
unlike the way they occur in dreams, except it was accompanied by the
strong feeling that it had actually happened. (As you will see, it
is not only brain-stimulation-based "recovered memories" that turn out
to be unreliable, but therapist-elicited ones too!)

> i remember you were saying in the lecture that even
> when an ECT patient doesn't remember the treatment, when he's brought
> back to the room to have another ECT, he'll feel frightened...
> this is not an imagined episode, he just isn't able to recall what it
> is....

Yes, but the two cases are different: The ECT patient is frightened
because of implicit memories or Pavlovian associations that are
in him though he does not remember the episode. So here it's fear
without recalling the event. With brain stimulation (which should not be
confused with electroconvulsive therapy!) it's a conscious memory that
it evokes, only it didn't really happen.

Cortical stimulation is done when a patient is being operated for, say,
epilepsy, to probe certain areas before removing them because the
surgeon is especially anxious not to take out memory and language
related areas if he can prevent it.

During this kind of brain stimulation, the patient is awake and does not
have general anesthesia (because the brain does not have any pain
sensation of its own -- it's too busy registering pains from the rest
of the body)!. So the patients are conscious of the "recovered memories"
when they are elicited by the stimulation, and they remain conscious of
having remembered them after the operation.

With ECT, the patient is anesthetised (so they are asleep) and curarised
(so they don't injure themselce during the ECT, which would otherwise
elicit a grand mal seizure). They don't remember any of it, but feel
fear when brought to it the next time.

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