THE FUNCTIONAL-ROLE OF EXCITATORY AND INHIBITORY INTERACTIONS IN CHOPPER CELLS OF THE ANTEROVENTRAL COCHLEAR NUCLEUS

Chopper cells in the anteroventral cochlear nucleus of the cat maintai n a robust rate-place representation of vowel spectra over a broad ran ge of stimulus levels. This representation resembles that of low thres hold, high spontaneous rate primary auditory nerve fibers at low stimu lus levels, and that of high threshold, low spontaneous rate auditory- nerve fibers at high stimulus levels. This has led to the hypothesis t hat chopper cells in the anteroventral cochlear nucleus selectively pr ocess inputs from different spontaneous rate populations of primary au ditory-nerve fibers at different stimulus levels. We present a computa tional model, making use of shunting inhibition, for how this level de pendent processing may be performed within the chopper cell dendritic tree. We show that this model (1) implements level-dependent selective processing, (2) reproduces detailed features of real chopper cell pos t-stimulus-time histograms, and (3) reproduces nonmonotonic rate versu s level functions in response to single tones measured.