Different representations of tooth chatter and purr call in guinea pig auditory cortex.

Multielectrode arrays were used to compare responses to tooth chatter and purr calls from all eight areas of the auditory cortex in anaesthetized guinea pigs. These calls have different behavioural contexts: males emit tooth chatters in aggressive encounters and the purr call during courtship behaviour. Of the two core areas, the primary auditory cortex responded better to both signals than the dorsocaudal core area. Of the six belt areas, the ventral transition area was found to be exceptionally sensitive to tooth chatter and less responsive to purr. The small rostral field responded faithfully to the purr, but not to tooth chatter, and ventrorostral belt often showed on/off responses; other belt areas were unresponsive.