The amygdala encodes specific sensory features of an aversive reinforcer

Studies of reconsolidation, in which retrieved memories are altered and restored, offer an approach for exploring the associative structure of fear memory. We found that exposure to the unconditioned stimulus initiates an unconditioned stimulus-specific reconsolidation of learned fear in rats that depended on the amygdala. Thus, specific features of the unconditioned stimulus appear to be encoded in the amygdala as part of fear memories stored there.