Re: Progress: What does it mean to you?

From: Smigrodzki, Rafal (SmigrodzkiR@MSX.UPMC.EDU)
Date: Sun Jun 03 2001 - 17:15:56 MDT


Samantha wrote:

  Does it? A Tale of Two Cities is a set of words/ideas. It is a
  story. A printout of this story exists in spacetime. But many
  different version can exists with arbitrary locality as long as
  the
  ideas/story can be found within them. I don't believe I know
  the *me* as simply as I know this story. So I don't see how I
  can make the query very objective. In principle it is ok but
  the particulars get pretty squirrelly.

##I would think that the me-recognition engine in your mind (and in mine)
works as follows:

There is a number of agents and processes dealing with various aspects of
identity. They provide input, receive feedback, and come up with a decision
which can be quite unequivocal (my chair is not me, me tomorrow is still
me), tentative (demented person who cannot speak, remember, is incontinent,
lost 90% of hippocampal neurons - is not really me anymore, I think), or
befuddled (a construct made of my left hemisphere and Ronald Reagan's right
one - I really don't know how I would call it). The limbic system (including
the insular cortex) votes on the basis of visceral input (hunger - if I feel
it,through the activity of the insula - it's part of me). Parts of the
parietal cortex vote on the basis of a model of space, which contains a few
specialized maps: damaging them in a stroke can produce neglect of the
opposite side of body, with the patient denying that his arm is a part of
his body. Parts of the frontal cortex (the frontopolar cortex, putatively
responsible for moral reasoning) would vote on the basis of moral belief
analysis (if my cryonics scheme went slightly wrong and I were resurrected
with all my explicit memories, as well as a firm belief in, let's say,
Raelianism, maybe due to temporal cortex dysfunction, I would disavow any
links to such a botched copy). The ACC is detecting dicrepancies between the
various agents, and directs attentional (read: computational) resources to
their resolution. With ACC damage patients are unconcerned about pain
(although they still feel it) and somewhat cognitively impaired. And then of
course there are other units - the supplementary motor cortex, the secondary
somatosensory cortical areas, and others we know even less about.

So yes, it's quite squirrelly but the way neuroscience is going forward, we
might have a much better understanding in the next 20 - 30 years. Yet
another piece of real estate the philosophers will loose.

Rafal Smigrodzki MD-PhD
Dept Neurology University of Pittsburgh
smigrodzkir@msx.upmc.edu



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