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Auditory and visual cortex: function and staining?

matt spitzer mwspitze at uci.edu
Wed Nov 9 15:18:09 EST 1994

In article <94Nov9.131035est.35 at psych.psych.toronto.edu>,
scott at PSYCH.TORONTO.EDU (Brian Scott) wrote:

> Well this seems like a sensitive time to ask questions on this newsgroup
> unless you've proven that you've already done _extensive_ research.  Well,
> I've decided to risk criticism and do both simultaneously.  Before I ask my
> question, I'd like to mention that _yes_ I've looked at Medline already but
> haven't had much success.  Here goes...l

P.B. Cook's criticism is IMHO entirely appropriate.  If a question posted
here can be answered with one or two key word searches on Medline, it's
best addressed in that way.  But yours is an excellent example of a
question that would not be easily addressed in that way.

> Does anyone know of any references to studies which have looked for a
> correlation between cell function in the visual and auditory corticies
> (cortexes?) and staining for specific substances?  I know you're going to
> say "There are millions!", but I'm especially interested in any
> immunocytochemistry work related to cells with functions like direction
> selectivity, edge detection, frequency selectivity, rising or falling FM
> sweeps etc...  Other types of staining are appreciated too.  I've seen lots
> of work on AChE in Auditory cortex but it looks like it stains all over and
> is not located in functionally specific cell types, which is what I'm
> looking for.     
	Unfortunately, unlike the primate visual cortex which is nicely arranged
in blobs, stripes, and hypercolumns, no comparable organizational
principles have yet been identified in auditory cortex of non-echolocating
mammals. There is some anatomical and physiological evidence that A1 may be
arranged in binaural bands, composed of neurons with similar binaural
interaction classes.  However, the existence of binaural bands is not
universally accepted.  This issue is further complicated by lack of
consesus on classification of binaural interactions.  Christoph Schreiner
has provided evidence for regional segregation of units based on a number
of physiological measures, including sharpness of frequency tuning,  within
A1.  Certainly, based on measures used thus far the degree of functional
compartmentalization in A1 does not approach that in visual cortex.  In
bats, however, there is considerable evidence of functional
compartmentalization.  So, I guess what I'm saying is that, even if you had
nice regional segregation of a specific anatomical marker, it is unlikely
that you would be able to relate it to an underlying physiological
organization.  But if you did, it would be big news.  A lot of people are
currently working on this issue.

	You wanted recommendations for a lit. search.  I would suggest looking up
binaural bands, or binaural organization.  Also, work by Tom Imig,
Christoph Schreiner, and Nobuo Suga (for work on bats). You will have to
look in the late 70's and early '80s, which you can do by changing the date
set on medline, or by getting hold of a comprehensive review chapter or
book on auditory cortex.  That should get you started. 


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