Monoamine oxidase-A genetic variations influence brain activity associated with inhibitory control: New insight into the neural correlates of impulsivity

Background: Previous evidence has shown that genetic variations in The serotoneigic system contribute to individual differences in Personality traits germane to impulse control. The monoamine oxidase-A (MAO-A) gene, coding for an enzyme primarily involved in serotonin and noradrenaline catabolism, presents a well-characterized functional polymorphism consisting of a variable number of tandem repeats in the promoter region, with high-activity and low-activity variants. High-activity allele carriers have higher enzyme expression, lower anzine concentration, and present higher scores on behavioral measures of impulsivity than low-activity allele carriers. Methods: We studied the relationship of this polymorphism to brain activity elicited by a response inhibition task, (Go/NoGo task), using blood oxygenation level-dependent (BOLD),functional magnetic resonance imaging in 24 healthy men. Results: Direct comparison between groups revealed a greater BOLD response in the right ventrolateral prefrontal cortex (Brodmann's area [BA] 45/47) in high-activity allele carriers, whereas 61 greater response in the right superior parietal cortex (BA 7) and bilateral extrastriate cortex (BA 18) was found in low-activity allele carriers. Conclusions: These data suggest That a specific genetic variation involving serotonergic catabolism can modulate BOLD response associated with human impulsivity.