Latency in the ascending auditory pathway determined using continuous sounds: comparison between transient and envelope latency.

The gross responses from the cochlea (round window) and two nuclei of the ascending auditory pathway of the rat in response to tone and noise bursts (compound action potentials) were compared with those recorded in response to continuous tones and noise that was amplitude modulated with pseudorandom noise. The cross-correlation function between: (1) the averaged response to the sounds that were amplitude modulated with the pseudorandom noise, and (2) one period of the pseudorandom noise, were obtained. The compound action potentials and the cross-correlation functions both had a series of peaks. The two functions had a similar morphology. The latency of the peaks in the cross-correlation showed less dependence on sound intensity than did the latency of the peaks in the compound action potentials.