Evoked potential recording in the IC. a IC–recording positions. The penetration sites across individuals were normalized according to two references; Cbl−Cerebellum, IC−Colliculus inferior, NCx−Neocortex, SC−Colliculus superior, hd−hemispheric divergence. b Examples of audiograms from separated loci across the IC in one animal. Regardless of the penetration site, the course of the threshold curves evoked by acoustic stimulation is similar.