Prefrontal cortical activity during the Stroop task: New insights into the why and the who of real-world risky sexual behavior

Background Research suggests that deficits in both executive functioning and trait impulsivity may play a role in risky sexual behavior. At the neural level, differences in regulation of the prefrontal cortex have been linked to impulsivity, measured neurocognitively and through self- report. The relationship between neurocognitive measures of executive control and trait impulsivity in predicting risky sexual behavior has not been investigated.

Purpose To investigate the relationship between neural functioning during the Stroop task and risky sexual behavior, as well as the effect of individual differences in urgent (positive and negative) impulsivity on this relationship.

Methods 105 sexually active men who have sex with men (MSM) completed the Stroop task during functional magnetic resonance imaging scanning. They also completed impulsivity inventories and self-reported their risky sexual behavior (events of condomless anal sex in the last 90 days).

Results Risky participants had greater activation than safe participants during the color congruent condition of the Stroop task in anterior cingulate cortex/dorsomedial prefrontal cortex, dorsolateral prefrontal cortex, left frontal pole, and right insula. Across these regions, this neural activation mediated the link between (positive and/or negative) urgent impulsivity and risky sexual behavior.

Conclusions Findings suggest that the brains of men who engage in risky sexual behavior may employ a different distribution of cognitive resources during tasks of executive functioning than men who practice safe sex, and that this may relate to differences in the prefrontal cortical/fronto- insular system responsible for impulse control.