Subject: Re: AUDITORY Digest - 7 Oct 2002 to 8 Oct 2002 (#2002-168) From: Jont Allen <jba(at)auditorymodels.org> Date: Wed, 9 Oct 2002 09:24:18 -0400Dear Auditory list, I don't see why there is a conflict with the various views. Pitch features, such as periodicity, place information, etc. could be extracted and recoded across the auditory cortex (or other places) tonotopic maps, and then sent upstairs for further processing and integration, using a different representation, rather than such a primitive synchrony code. Wouldn't such a strategy meet all the requirements described? This seems so obvious I hesitated in mention it, actually. Maybe I am just spaming. Jont > > >------------------------------ > >Date: Tue, 8 Oct 2002 11:40:00 +0200 >From: Martin Braun <nombraun(at)POST.NETLINK.SE> >Subject: Re: pitch neurons > >Israel Nelken asked: > >>why is there such a pressure >>to assume low-level representation (i.e. subcortical) of pitch? >> > >Dear Eli and List, > >the reason why physiological research focused on the exploration of >subcortical mechanisms when looking for the pitch detector simply was that >psychoacoustic data demanded a spectrotemporal mechanism. This ruled out the >auditory cortex, because phase-coupling to pitch-relevant harmonics does not >occur there. The highest level where it occurs is the auditory midbrain. > >During the past 15 years all necessary elements for pitch extraction have >been found in the auditory midbrain (inferior colliculus, in the upper >brainstem). Arrays of best-pitch neurons filter out the pitch frequency of >complex sound signals, in the same way as arrays of best-frequency hair >cells filter out spectral frequencies in the cochlea. Whereas the tuning >properties of hair cells in the cochlea are mechanical and electrical, the >tuning properties of pitch neurons are purely electrical. These neurons have >tuned membrane potential oscillations, which are either intrinsic, due to >unit-specific distribution of membrane channel types, or imported from input >neurons. This last question is still an open one. > >Martin > >------------------------------------------- >Martin Braun >Neuroscience of Music >S-671 95 Klässbol >Sweden >e-mail: nombraun(at)post.netlink.se >web site: http://hem.netlink.se/~sbe29751/home.htm > >------------------------------ > -- Jont B. Allen, jba(at)auditorymodels.org; 908/654-1274voice; 908/789-9575 fax 382 Forest Hill Way Mountainside NJ 07092 http://auditorymodels.org/jba ``A paradox is simply an error out of control'' --E.T. Jaynes, Chapter 15 of http://bayes.wustl.edu/etj/prob/