Abstract:
Characteristics of single neuron responses underlying possible mechanisms for the extraction of the pitch of complex tones in the inferior colliculus (ICC) of anesthetized ferrets has been studied. Sounds such as amplitude-modulated tones, trains of clicks, and other spectrally complex sounds were used. It has been observed that the fine structure of a contralaterally presented stimulus can be found, perhaps even enhanced, in the firing patterns of collicular stellate cells. Ranges of latencies, best modulation frequencies, and center frequencies in the responses were found, as found before; more importantly perhaps, very short, stimulus-independent periodicities in the response patterns were found, as by Langner [G. Langner, Hear. Res. 60, 115--142 (1992)]. The functional significance of these findings, and in particular of these ``intrinsic oscillations,'' with respect to the problem of pitch extraction by the auditory pathway, will be discussed in the context of a model. [Work supported by ONR, NIDCD, and NSF.]