抄録
One of the most prevailing views on the functional localization of human cognition is the functional hemispheric asymmetry, wherein the left hemisphere is implicated primarily in verbal processing whereas the right hemisphere is implicated primarily in nonverbal processing. Inhibitory control has been known to be involved in the lateral prefrontal cortex, particularly in the posterior inferior frontal gyrus (IFG). However, it remains unclear what factor determines the hemispheric dominance of the activation in the IFG during inhibitory control. In this fMRI study we tested whether the hemispheric asymmetry principle applies to the IFG activation during inhibitory control. A flanker task, one of the major tasks used to examine inhibitory control, was devised that allowed us to manipulate the modality of the presented flanker stimulus (color word or colored patch) from which interference effects originate, keeping the total stimulus modality effects balanced. Consistent with previous studies of the flanker task, the posterior part of the IFG was prominently activated. Although the dorsal frontal areas showed prominent hemisphere-by-modality interaction in simple visual effects, the IFG never showed the hemisphere-by-modality interaction in inhibitory control of flanker interference. These results suggest that the left and right IFG activation during inhibitory control is independent of the modality of presented stimulus from which the interference effects originate. [J Physiol Sci. 2007;57 Suppl:S168]
