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Article 6252 of comp.ai.philosophy:
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>From: bill@nsma.arizona.edu (Bill Skaggs)
Newsgroups: comp.ai.philosophy
Subject: Re: Spectral Data Processing in the Brain
Message-ID: <BILL.92Jun14173601@ca3.nsma.arizona.edu>
Date: 15 Jun 92 00:36:01 GMT
References: <632@trwacs.fp.trw.com>
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Organization: ARL Division of Neural Systems, Memory and Aging, University of
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In-Reply-To: erwin@trwacs.fp.trw.com's message of 14 Jun 92 16: 16:24 GMT

erwin@trwacs.fp.trw.com (Harry Erwin) writes:

   Owls are known to use narrow-band spectral data
   in the processing of sound. This appears to be power;
   is there any evidence of phase data being generated/
   used in any species?

In many species information about the phase of sounds is neurally
encoded for some range of frequencies.  Phase differences between the
two ears are used to tell the directions sounds come from -- that's
why it's so hard to tell the source for very high-pitched sounds
(whose phase is not encoded).  Phase may also play a role in the
recognition of complex timbres.  See any good intro to the
neurophysiology of hearing for details.

   Reason for asking: if phase data are not generated/
   used, then brains do not perform coherent processing
   of input signals, and the holographic brain hypothesis
   (for sensory data processing/storage) is false.

Well, you'd actually be pretty hard-pressed to find many
neurophysiologists who think that the holographic hypothesis is
literally true.  It does not seem that brain tissue has a sufficiently
regular structure to make it work.  Kohonen discusses this in some
detail in "Self Organization and Associative Memory" (a great book, by
the way).

	-- Bill


