Re: Efferent feedback to the organ of the Corti

["David W. Smith, Ph.D." <earsdws@xxxxxxxx>]

Matt, 
I think if you review Sato et al. (The innervation of outer hair cells:
3D reconstruction from TEM  serial sections in the Japanese macaque), Hearing
res. 135,  29-38, 1999, you will see this is not precisely true.  In  fact,
the apex has a very robust, and perhaps qualitativiely different medial efferent
supply than do more basal regions.  Your statement "In fact the afferent
system is reported to be oversampled by the efferent system at high frequencies,
one to one sampled for medium frequencies and under-sampled for low frequencies,"
 I believe is incorrect.
David SMith.

Matt Flax wrote:
> I would like to point researchers to the article [1] which slivers the
> cochlea for electron microscope inspection. Of interest is the finding
> that the efferent neural innervation is mostly in contact with the high
> frequency portion of the spiral ganglion / organ of the Corti. There is
> completely minimal contact for the low frequency portion of the  spiral
> ganglion / organ of the Corti. There is medium contact for medium
> frequencies.
> In fact the afferent system is reported to be oversampled by
> the efferent system at high frequencies, one to one sampled for medium
> frequencies and under-sampled for low frequencies.
>
> This suggests that low frequencies are uniquely unaffected by the
> efferent system. Medium frequencies are affected by efferent feedback and
> high frequencies are seriously under the influence of the efferent
> system.
>
> It is also noted that the efferent system is believed to develop post
> birth.
>
> Matt
>
> [1]
> @article{Thiers:2002,
>    author    = {Thiers, F.A. and Burgess, B.J. and Nadol, J.B.},
>    title     =
> {\href{http://www.elsevier.com/locate/issn/03785955}{Axodendritic and
> dendrodendritic synapses within outer spiral bundles in a human}},
>    journal   = {Hearing Research},
>    pages     = {97-104},
>    year      = {2002},
>    volume    = {164},
>    issue     = {1-2}
> }
>
> --
> http://mffm.darktech.org
>
> WSOLA TimeScale Audio Mod  : http://mffmtimescale.sourceforge.net/
> FFTw C++                   : http://mffmfftwrapper.sourceforge.net/
> Vector Bass                : http://mffmvectorbass.sourceforge.net/
> Multimedia Time Code       : http://mffmtimecode.sourceforge.net/