Thalamic mechanism of learning and memory

The role of the thalamus in highlevel cognitive function such as learning and memory remains poorly understood.Here we systematically examined the role of paraventricular thalamus(PVT) in associative learning.We trained mice with olfactory conditioning task in which different olfactory cues were associated with different outcomes includes reward,punishment or nothing.Both fiber photometry and single-unit recordings revealed that PVT were robustly activated by a variety of behaviorally significant events including reinforcing stimuli and their predicting cues,as well as omission of the expected reward.PVT responses are proportional to the stimulus intensity and modulated by changes in homeostatic state or behavioral context.Optogenetic inhibition of the PVT responses suppresses appetitive or aversive associative learning and reward extinction.Our findings demonstrate that the PVT gates associative learning by providing a dynamic representation of stimulus salience.