Changes in the Latency of Mouse Inferior Colliculus Neuron Responses Depending on the Position and Direction of Movement of Spectral Contrast

Abstract

Changes in the latency of mouse (Mus musculus) inferior colliculus neuron responses in the presence of wideband sound signals with spectral notches and noise bands with regularly varying central notch/band frequencies were studied. Relationships between the latency and the magnitude of the response on the one hand and the central notch/band frequency on the other were obtained (latency and spike count functions). Crossing of the margins of the excitatory areas of the responses of the frequency receptive fields of neurons by spectral notches/noise bands could lead to displacement of latency functions (and corresponding displacements in spike count functions). Direction-dependent shifts in latency and spike count functions were more characteristic of primary-like and V-shaped neurons. The most interesting feature of the directional sensitivity of inhibition-dependent neurons was the selective decrease in the latency and selective synchronization of the initial spike response (with a corresponding increase in the spike count). The dynamic properties of inhibition-dependent neurons can be explained on the basis of their selective sensitivity to the position of the spectral contrast in the frequency receptive field, which is associated with disinhibition, and by the nature of the distribution of the excitatory and inhibitory inputs. The extents of these effects depended on the spectral shape of the signals and the widths of the spectral notches.