The role of the right inferior frontal gyrus: inhibition and attentional control

TLDR

Interest in the right inferior frontal gyrus (RIFG) as a key region for response inhibition is growing, yet existing studies rarely control for attentional demand, leaving unclear whether RIFG supports inhibition specifically or general salient cue detection. The study aimed to clarify whether RIFG activity reflects inhibition or cue detection by keeping Stop Signal Task stimuli constant while varying the required response to the stop cue. Using fMRI, the authors manipulated the response demanded after the stop signal while keeping the task stimuli unchanged. Results showed RIFG activation whenever salient cues were detected, independent of whether the cue prompted inhibition, a motor response, or no response.

Abstract

There is growing interest regarding the role of the right inferior frontal gyrus (RIFG) during a particular form of executive control referred to as response inhibition. However, tasks used to examine neural activity at the point of response inhibition have rarely controlled for the potentially confounding effects of attentional demand. In particular, it is unclear whether the RIFG is specifically involved in inhibitory control, or is involved more generally in the detection of salient or task relevant cues. The current fMRI study sought to clarify the role of the RIFG in executive control by holding the stimulus conditions of one of the most popular response inhibition tasks-the Stop Signal Task-constant, whilst varying the response that was required on reception of the stop signal cue. Our results reveal that the RIFG is recruited when important cues are detected, regardless of whether that detection is followed by the inhibition of a motor response, the generation of a motor response, or no external response at all.