Re: pitch neurons

[Israel Nelken <israel@xxxxxxxxxxxxx>]

Martin and list,
       I think that the idea that neurons in the inferior colliculus are
sensitive to different periodic modulations of their input is generally
accepted. Many neuronal mechanisms would do that - not only intrinsic
oscillations. I don't think this is really the issue about which I feel
uncomfortable.
       The point is that these neurons mostly respond to sounds with energy
content within their tuning curve (with a lot of fine print attached, I
agree), and therefore cannot be interpreted as 'pitch neurons'. When you
say 'pitch neuron', I understand that you are looking for a neuron that
should respond to pitch irrespective of the underlying physical
structure of the stimulus - missing fundamental or not, iterated ripple
noise, high-pass filtered click trains, binaural or monaural, and so on
and so forth. I don't think that there's any data in the literature
(including the very nice Fishman et al. paper that you referred to in a
previous message) that even come close.
       It is precisely this high abstraction level of the pitch, its
independence of so many of the physical attributes of the underlying
sounds, that to my opinion argues for a high level of processing for the
common denominator of all of these sounds. This however does not
preclude a partial extraction of some of the features of such sounds
earlier (e.g. periodicity at the level of the IC).
       Eli

--
==================================================================
Israel Nelken                     | Tel: Int-44-1865-272438
Dept. of Physiology,              | Fax: Int-44-1865-272469
Hebrew University -               |
       Hadassah Medical School    |
P.O.Box 12272, Jerusalem 91120    | Email:israel@md.huji.ac.il
ISRAEL                            |
==================================================================