Neurone response latency in the inferior colliculus in relation to the auditory brainstem responses (ABR) in the guinea pig.

In order to determine the possible source of the later vertex positive waves of the guinea pig auditory brainstem response (ABR), we have measured field potentials on the surface and at depths through inferior colliculus whilst making concurrent recordings of single unit responses (using identical broadband click stimuli). We find neurones, restricted to the antero-ventral inferior colliculus, with characteristic frequencies in excess of 12 kHz which have well synchronized onset responses short enough (c. 5 ms) to contribute to the P5 wave of the ABR.