Effective connectivity within the ventromedial prefrontal cortex-hippocampus-amygdala network during the elaboration of emotional autobiographical memories

摘要

Autobiographical memories (AMs) are often colored by emotions experienced during an event or those arising following further appraisals. However, how affective components of memories affect the brain-wide network recruited during the recollection of AMs remains largely unknown. Here, we examined effective connectivity during the elaboration of AMs - when retrieved episodic details are integrated to form a vivid construct - in the network composed by ventromedial prefrontal cortex (vmPFC), hippocampus and amygdala, three key regions associated with memory and affective processes. Functional MRI data was collected while volunteers recollected personal events of different types of valence and emotional intensity. Using dynamic causal modeling, we characterized the connections within the triadic network, and examined how they were modulated by the emotional intensity experienced during an event, and the valence of the affect evoked when recollecting the associated memory. Results primarily indicated the existence of a vmPFC to hippocampus effective connectivity during memory elaboration. Furthermore, the strength of the connectivity increased when participants relived memories of highly emotionally arousing events or that elicited stronger positive affect. These results indicate that the vmPFC drives hippocampal activity during memory elaboration, and plays a critical role in shaping affective responses that emanate from AMs.