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.
aDepartment of Psychiatry, Hangang Sacred Heart Hospital, Hallym University Medical Center, Seoul
bInstitute of Psychological Science, Seoul National University, South Korea
Correspondence to Dr Byung-Joo Ham, MD, PhD, Department of Neuropsychiatry, Hangang Sacred Heart Hospital, Hallym University Medical Center, Yongdungpo-Dong, Yongdunpo-Gu, Seoul 150-719, South Korea
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Received 24 December 2007; accepted 20 January 2008