My research focuses on neurobiology of affective memory. We study how memory of fearful or pleasurable events is formed, maintained and expressed in the brain. We trained rats in learning tasks motivated by shock (e.g. inhibitory avoidance) or reward (e.g. conditioned place preference) and measure the neurophysiological or biochemical correlates of learning, we also manipulate neural operations in various brain sites during memory consolidation or expression and observe the effects. Our findings accumulated in the past 30 years suggested that while the amygdala is involved in formation of affective memory, it is by no means the site of permanent storage for such memory. Neuronal activity in the basolateral or central amygdala nucleus was altered by the training experience and the change persisted in the 1-day retention test. Various treatments administered to the amygdala shortly after training of the inhibitory avoidance task affected memory in subsequent retention tests. Such effects were also observed in other areas including the hippocampus, nucleus accumbens, septal area, medial prefrontal cortex, etc. Suppression of the amygdala or other subcortical areas during retention tests impaired retention of a recent fear memory acquired a few days ago. Conversely, suppression of the insular, medial prefrontal, or perirhinal cortices during retention tests impaired a remote fear memory acquired several weeks ago. Thus, formation of memory for an inhibitory avoidance response involves wide spread brain regions and the trace undergoes dynamic changes over brain in a retention period. These results from my laboratory create a picture of a distributed circuit underlying fear memory, which is quite different from a prevailing view that fear memory involves only the amygdala. The discrepancy could be due to whether the fear experience engages operant behavior to cope with the stress. Involvement of the nucleus accumbens may allow rats to actively cope with the incoming danger, while that of the hippocampus may allow all stimuli in learning to be integrated into a configuration that affords versatile utilization. Thus, the amygdala cooperates with the action of various brain regions in coding the fear memory and allows flexible reactions to its subsequent retrieval.