Amygdala-Dependent Signaling Pathways and Regulating Circuits in Fear Memory

Fear memory, a profound emotional memory formed in response to threatening events, is vital to the survival and adaptation of individuals. The amygdala, a central hub in the formation, storage, and expression of fear memory, extensively connects with other brain regions, particularly the hippocampus and hypothalamus, allowing it to rapidly integrate sensory information and generate emotional responses. Past research on the regulatory circuits of fear memory has focused on the amygdala, prefrontal cortex, and hippocampus, emphasizing their interactive roles in the formation, consolidation, and extinction of fear memory. However, new circuits and signaling pathways have been identified, leaving many unresolved mysteries about the specific mechanisms of signaling pathways and circuits that depend on the amygdala in fear memories. Therefore, this review focuses on the roles of the different signaling pathways and circuits of the amygdala in fear memories, including their interactions with the hippocampus, cortex, and other brain regions. Further, synaptic plasticity and the regulation of inhibitory interneurons in the amygdala by the ventral prefrontal cortex are discussed. The aims of this review are to advance our understanding of the amygdala's mechanism in fear memory, provide new insights for the prevention and treatment of related disorders such as post-traumatic stress disorder (PTSD), and offer guidance for future research.