Response to acoustic stimuli increases in the ventral cochlear nucleus after stimulus pairing.

Recordings of activity in response to click and hiss were made from 364 units of the ventral cochlear nucleus of cats. The unit response to acoustic stimuli increased after forward or backward pairing of the stimuli with glabella tap and hypothalamic electrical stimulation. The results provide evidence against the widely held view that transmission through this initial brain stem relay of the auditory system is invariant, and suggest, instead, that the activity of the ventral cochlear nucleus changes to support increased attentiveness to acoustic signals after variably ordered pairing of conditioned and unconditioned stimuli.