A Process-specific Functional Dissociation of the Amygdala in Emotional Memory

Converging evidence highlights the important role of the amygdala in the enhanced memory for emotional material. However, it is unknown whether any regional and/or hemispheric specificity exists regarding its involvement in the different memory stages, such as encoding and retrieval. We directly addressed this issue by conducting an event-related functional magnetic resonance imaging study of memory for faces with different emotional expressions, in which both encoding and recognition were scanned. We found significant amygdala activation associated with both successful encoding and retrieval of fearful faces. Critically, a direct comparison between both stages revealed that whereas the right amygdala was involved in emotional memory formation, the retrieval of those memories relied on the left amygdala. Thus, this study demonstrates a hemispheric dissociation of amygdala involvement in different stages of emotional memory in humans.