RECORDINGS Of activity in response to click and hiss were made from 36
4 units of the ventral cochlear nucleus of cats. The unit response to
acoustic stimuli increased after forward or backward pairing of the st
imuli with glabella tap and hypothalamic electrical stimulation. The r
esults provide evidence against the widely held view that transmission
through this initial brain stem relay of the auditory system is invar
iant, 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 stimu
li.