Long-term memory for contextual attributes: dissociation of amygdala and hippocampus.

Rats were given passive avoidance training within a distinctive environment followed by subseizure level stimulation of the hippocampus or amygdala. The animals were then tested for retention of the aversive experience using a partial cue (subset of the original training environment) and a complete cue (the original training environment). Post-trial hippocampus stimulation produced a retention deficit in both the partial and complete cueing conditions, while post-trial amygdala stimulation produced an intermediate retention deficit in the partial, but no deficit in the complete cueing condition. It is proposed that the hippocampus, but not the amygdala, is involved in processing of the environmental context utilizing spatial temporal attributes.