Network-level neural basis of individual differences in emotional memory enhancement

The memory-enhancing effect of emotional arousal is well-established but varies considerably across individuals. To uncover the neural basis of this variability, we conducted an fMRI study in 1498 young adults who encoded emotional and neutral pictures, followed by a recall task. A voxel-based brain-behavior correlation analysis of encoding-related regional responsivity revealed that regions commonly implicated in emotional memory enhancement at the group level, such as the amygdala, did not significantly correlate with individual differences. In contrast, a network-based analysis of task-related functional connectivity during encoding identified six functional connectivity networks that correlated with individual emotional memory enhancement, encompassing many of the regions identified at the group level, including the amygdala, as well as additional regions. Four networks were positively correlated with emotional memory enhancement, while two networks were negatively correlated. Together, these findings suggest that inter-individual variability in emotional memory enhancement may be more robustly captured by distributed network-level responsivity than by regional responsivity in isolation. This study provides neurofunctional insights into individual differences in emotional memory enhancement, and is conceptually relevant for future research on conditions characterized by excessively strong emotional memories, such as post-traumatic stress disorder.