> I agree with
> your idea, but I'm also still wrestling with what a "pleasure center" is.
> Isn't it at bottom an intellectual response to something physical?
Actually, there doesn't seem to be any real pleasure centers in the
brain. In the 50's (?) researchers experimented with rats having
electrodes implanted in various parts of the brain, and found that in
some areas the rats would do anything to get stimulance. This led to the
theory that there were "pleasure centers", invoking nightmarish visions
of electrical addiction (Niven's "tasp"). But later implants in humans (I
think doctor Robert Heath and Jose Delgado were the pioneers here -
anybody who knows what they do now?) turned out a bit differently. There
were some ares where they felt pleasant stimuli, but no electronic
orgasms. However, it became clear that the relevant areas were rather
motivation systems - in some sense motivation is deeper than
pleasure/pain, although they are often hard to distinguish.
> What I want to understand is what these structures really do, and whether
> that is ultimately a "physical" or "intellectual" function.
Is there really a difference? In some sense our intellectual functions
are physical too.
As far as I know, the structures to look at is in the limbic system and in
the brainstem, especialy the dopaminergic system that reaches into the
limbic system and the cortex. Especially important is the nucleus
accumbens, which appears to be the central relay point (all
psychologically addicting seem to drugs stimulate this nucleus), and the
mesolimbic nerve bundles reaching the frontal cortex which link our
actions and cognition with pleasure/motivation - if they are severed
nothing seems to have any special meaning, and if they are weakened the
person needs stronger stimuli to "feel alive".
This is an exciting area, which I unfortunately haven't had the
opportunity to study well enough.
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Anders Sandberg Towards Ascension!
nv91-asa@nada.kth.se http://www.nada.kth.se/~nv91-asa/main.html
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