Interplay of Amygdala and Cingulate Plasticity in Emotional Fear

Figure 1

Interplay of the cortex and hippocampus/amygdala in fear memory. There are two major hypotheses related to the brain network involved in fear memory. Depending on the different types of conditioning protocols, it is likely that both mechanisms may take place. In model A, early fear memory is formed within the hippocampus and/or amygdala. At some time point after learning (e.g., during sleep), some of this information is replayed and transferred into the cortical synapses. After the formation of remote memory in the cortex, early synaptic changes are unlikely important. The exact synaptic and molecular mechanisms for the replaying remain to be investigated or proved. According to this model, the cortical activity is not required for the formation of early fear memory. In model B, early synaptic potentiation related to fear conditioning happens at synapses located in all three major areas, including the hippocampus, amygdale, and cortex. The interconnections among these three areas may be further enforced after the formation of early memory. Similar to model A, late or remote memory is mainly stored in the cortical synapses.