Basic reference for auditory cortex
mwspitze at uci.edu
Thu Oct 20 17:07:45 EST 1994
In article <3864bh$rht at muller.loria.fr>, durand at loria.fr (Stephane Durand)
> Our work is to design neuromimetic architecture for speech recognition with
> computer. To achive our goal, we take inspiration in neurobiological
> data. It seems that cortex is organized with different areas each of
> them having a particular fonctionality. For instance, the primary area
> of visual cortex extracts visual features such as orientations.
> Regarding the auditory cortex, at the lower level, I believe we can find
> tonotopically organized maps. What kind of maps can we find at a upper level?
> Or, how can the word level be represented?
> Does it exist an organized area coding words (or syllables, phonemes)?
As you will find out when you start to delve into the literature, much
less is known about the functional organization of auditory cortex than is
known about visual cortex. As I said before, much more is known about the
neurobiology of auditory processing in cats, (I can't believe I left out
and nobody spanked me) bats and birds than in humans. This is a
particularly difficult problem given your interest, because language is
specific to humans. If you want to understand how acoustic information
specific to language is encoded and processed at the neuronal level, there
is not yet (and perhaps may never be) a suitable animal model. Of course,
some people such as those working on bird song may disagree strongly with
this last statement.
As for tonotopic maps, there are plenty of those to be had throughout
the auditory pathway, including cortex. In cat there are at least 4 or 5
tonotopically organized cortical fields. For an introductory discription,
see the chapter by Janine Clarey in the Neurophysiology volume of the
Springer series that I cited earlier. An outstanding question in the field
is what may be represented orthogonal to the tonotopic axis of the cortical
maps. Just to get you started on this immense issue, I suggest you look up
work by the following authors: C. Schreiner, T. Imig, J. Brugge, S.
Shamma, N. Suga, and D. Phillips (of course this is just a partial list,
but should be enough to keep you busy for quite some time).
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