Some preliminary observations on the interrelations between two-tone suppression and combination-tone driving in the anteroventral cochlear nucleus of the cat

Publisher Website
Google Scholar
Abstract
For units of the anteroventral cochlear nucleus in the cat, as for primary units, response to a best-frequency tone f1 was markedly reduced when a higher-frequency suppressing tone f2 of equal or greater intensity was presented simultaneously at a frequency separation corresponding, in the present experiments, to an optimal distance on the basilar membrane of about 0.5-0.8 mm. This distance did not seem to vary systematically with best frequency and may be related to critical bandwidth. Unit response to the combination tone, 2f2-f3, formed when f1 is omitted and f3 is added above f2, was compared with the unit''s response to a 3-tone stimulus. The 3 primary stimulus consisted of tones with equispaced frequencies and controllable phase and amplitude relations. Primary tone f1 and combination tone 2f2-f3 coincided at best frequency, while f2 and f3 lay above the tuning curve. The comparison of response to 2f2-f3 alone and of response to the resultant of f1 and 2f2-f3, while f1 phase is varied, allowed relative amplitudes to be calculated. They were such that f1 appeared suppressed in amplitude by f2 and f3, while 2f2-f3 was correspondingly less than cancellation-tone estimates. For constant f2 level, 2f2-f3 amplitude reached maximum when f3 amplitude almost equalled f2 and decreased markedly as f3 amplitude exceeds f2. When the combination tone resultant composed of 2f1-f2 and 3f2-2f3 lay at best frequency, variation in the phase of f1 produced a marked variation in rate of response to the resultant, appearing to parallel psychophysical results obtained by J. L. Goldstein.

This publication has 7 references indexed in Scilit: