Amygdala-hippocampal interactions in synaptic plasticity and memory formation

• Published in: Neurobiology of learning and memory Vol. 184; p. 107490
• Main Authors: Roesler, Rafael, Parent, Marise B., LaLumiere, Ryan T., McIntyre, Christa K.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.10.2021
• Subjects: Amygdala; Amygdala - physiology; Animals; Entorhinal Cortex - physiology; Hippocampus; Hippocampus - physiology; Humans; Memory consolidation; Memory Consolidation - physiology; Memory systems; Neural Pathways - physiology; Neuronal Plasticity - physiology; Synaptic plasticity; Memory consolidation; Amygdala; Memory systems; Hippocampus; Synaptic plasticity
• ISSN: 1074-7427; 1095-9564
• DOI: 10.1016/j.nlm.2021.107490

•We review research investigating how the amygdala modulates memories of emotional experiences.•The amygdala influences memory consolidation and related molecular changes in the hippocampus.•The amygdala modulates hippocampal memory via projections to the medial entorhinal cortex. 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 consolidation 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 hippocampus, 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 influences hippocampal-dependent memories, as well as synaptic plasticity, histone modifications, gene expression, 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.