Re: Efferent feedback to the organ of the Corti (Matt Flax )


Subject: Re: Efferent feedback to the organ of the Corti
From:    Matt Flax  <flatmax(at)IEEE.ORG>
Date:    Fri, 11 Oct 2002 01:17:48 +1000

David, please forgive me if I am incorrect. I am referring to [1] Figure 5 where the VR/NP Synapses on VP/NR NFs (Presumed Axodendritic Synapses) are depicted to become less numerous towards the 3'rd turn. Again, I am an electrical engineer, so please forgive me if I am mistaken, but I am assuming that these are efferent neural connections. I also refer to this posting to Auditory in 1996 : http://www.auditory.org/postings/1996/74.html Where it is stated ... "There are also efferent fibers near the IHC's. These originate in the lateral olivocochlear system, and make axodendritic synapses with the afferent fibers [3]". Matt [3] Nadol J.B., Jr., Synaptic morphology of inner and outer hair cells of the human organ of Corti, Journal of electron microscopy technique, 15, 187-196, 1990. [1] (at)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} } On Thu, Oct 10, 2002 at 06:48:53AM -0400, David W. Smith, Ph.D. wrote: > 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] > >(at)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/ > > > > > > > > > > > -- 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/


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