Amygdala-hippocampal interactions in synaptic plasticity and memory formation

Memories of emotionally arousing events tend to endure longer than other memories. This review compiles findings from several decades of research investigating the role of the amygdala in modulating memories of emotional experiences. Episodic memory is a kind of declarative memory that depends upon the hippocampus, and studies suggest that the basolateral complex of the amygdala (BLA) modulates episodic memory consoli-dation through interactions with the hippocampus. Although many studies in rodents and imaging studies in humans indicate that the amygdala modulates memory consolidation and plasticity processes in the hippo-campus, the anatomical pathways through which the amygdala affects hippocampal regions that are important for episodic memories were unresolved until recent optogenetic advances made it possible to visualize and manipulate specific BLA efferent pathways during memory consolidation. Findings indicate that the BLA in-fluences hippocampal-dependent memories, as well as synaptic plasticity, histone modifications, gene expres-sion, and translation of synaptic plasticity associated proteins in the hippocampus. More recent findings from optogenetic studies suggest that the BLA modulates spatial memory via projections to the medial entorhinal cortex, and that the frequency of activity in this pathway is a critical element of this modulation.

Automated summary

Memories of emotionally arousing events tend to endure longer, with the amygdala playing a crucial role in modulating episodic memory consolidation. Studies suggest that the basolateral complex of the amygdala influences hippocampal-dependent memories and synaptic plasticity. Recent optogenetic studies have provided insights into the specific pathways through which the amygdala affects hippocampal regions important for episodic memories.