Abstract
Serotonin (5-HT) has been reported to have a wide range of biological effects on behavior, and dysfunctional 5-HT neurotransmission in the central nervous system may cause behavioral diseases that are characterized by impulsivity. We investigated a possible role for the serotonergic system in human impulsive behavior by measuring how 5-HT2A receptor gene polymorphism (A-1438G in the promoter region) affects inhibitory motor control-related brain activity in a reward-punishment Go/No-go task using fMRI. Participants were instructed to learn to respond to active stimuli and inhibit their response to passive stimuli. During the No-go responses, right ventral prefrontal cortex (VLPFC) activation was relatively higher in participants for AA allele compared with participants for GG allele. The hyperactivity of VLPFC of AA allele carriers can be interpreted as a need of greater cognitive control to compensate for decreased behavioral inhibition efficiency. While activation of reward circuit, such as striatum, nucleus accumbens and hypothalamus show no differences between genotypes. Our finding shows the role of serotonergic neuro-modulation in human impulsive behavior.
