The effect of inferior colliculus lesions on auditory evoked potentials

The brain-stem auditory evoked potential (BAEP) was recorded in Nembutal anaesthetized cats before and after aspiration of the inferior colliculus on each side. The fast P1-P4 waves and the binaural interactions of P4 were unaffected by inferior colliculus removal. P5 and the following slow negative wave were reduced by inferior colliculus lesion. When only one inferior colliculus was ablated, this reduction was greater when the ear contralateral to the lesion side was stimulated.