background Memory for emotional events is biased in depression, and individual differences in emotional memory processing may represent a vulnerability factor to the development of depression. A key neural structure involved in emotional memory formation is the amygdala.
aim To investigate whether candidate genes associated with depression and enhanced emotional memory influence memory processing in the amygdala using functional mri.
methods In the first experiment, we investigated the influence of a single nucleotide polymorphism in the bdnf gene (Val66Met) that affects memory and influences depression vulnerability in a sex-specific manner. We tested 47 healthy volunteers who performed a recognition memory task with face stimuli. In the second experiment, we investigated the influence of a deletion variant in adra2b, the gene coding the alpha2b-adrenergic receptor, which is associated with enhanced memory for emotional stimuli and traumatic experiences. We tested 35 healthy volunteers who performed a recognition memory task with emotional stimuli.
results Results from the first experiment showed sex-specific bdnf Val66Met during successful memory encoding, with a larger contribution of the amygdala to memory formation in male Met allele carriers than male Val homozygotes, whereas no significant differences were observed in females. In the second experiment, the amygdala has a larger contribution to memory formation in deletion carriers than non-deletion carriers.
conclusion Together, these results demonstrate that variation in specific genes contributes to individual differences in amygdaladependent memory processing, which may contribute to the vulnerability to depression.