Inhibitory spillover: Intentional motor inhibition produces incidental limbic inhibition via right inferior frontal cortex

Neurocognitive studies have observed rIFC involvement in motor, cognitive, and affective inhibition, suggesting that rIFC is a common inhibitory mechanism across psychological domains. If true, intentional inhibition in one domain may have unintended inhibitory effects ("spillover") in other domains. The present study used an emotional go/no-go task that produces responses in both motor and affective domains, but induces intentional inhibition in only the motor domain. Data support the hypothesis that intentional inhibition in the motor domain, via rIFC, produces inhibitory spillover in the affective domain. Specifically, we observed increased rIFC along with reduced amygdala activity when participants intentionally inhibited motor responses during the presentation of negatively-valenced stimuli, and greater inverse connectivity between these regions during motor inhibition in a PPI analysis. Given the absence of intentional affect regulation, these results Suggest that intentional inhibition of a motor response dampens the amygdala activation coincident with affective stimuli to the extent that rIFC activation is higher. (C) 2009 Elsevier Inc. All rights reserved.