Monoamine oxidase A-uVNTR genotype affects limbic brain activity in response to affective facial stimuli

Monoamine oxidase A (MAOA) enzymatically degrades biogenic amines such as norepinephrine, dopamine, and serotonin, and plays a key role in the regulation of their neurotransmission. Allelic variations at the MAOA locus have been implicated in the neurobiology of aggression and impulsivity. We investigated the possible relationship between the MAOA-upstream variable number of tandem repeats (uVNTR) polymorphism and brain responses to negative facial stimuli, using functional magnetic resonance imaging (fMRI). We found a significant association between a low activity allele of MAOA- uVNTR and neural activation to negative facial stimuli. In the sad condition, participants with the low activity allele showed greater brain activity in the left amygdala. In the angry condition, participants with the low activity allele showed greater brain activity in the right anterior cingulate cortex and hippocampus. Our results suggest that MAOA-uVNTR polymorphism can affect activation of limbic regions, elicited by negative emotional stimuli.