title: Distinct frontal systems for response inhibition, attentional capture, and error processing.
abstract: Stopping an action in response to an unexpected event requires both that the event is attended to, and that the action is inhibited. Previous neuroimaging investigations of stopping have failed to adequately separate these cognitive elements. Here we used a version of the widely used Stop Signal Task that controls for the attentional capture of stop signals. This allowed us to fractionate the contributions of frontal regions, including the right inferior frontal gyrus and medial frontal cortex, to attentional capture, response inhibition, and error processing. A ventral attentional system, including the right inferior frontal gyrus, has been shown to respond to unexpected stimuli. In line with this evidence, we reasoned that lateral frontal regions support attentional capture, whereas medial frontal regions, including the presupplementary motor area (pre-SMA), actually inhibit the ongoing action. We tested this hypothesis by contrasting the brain networks associated with the presentation of unexpected stimuli against those associated with outright stopping. Functional MRI images were obtained in 26 healthy volunteers. Successful stopping was associated with activation of the right inferior frontal gyrus, as well as the pre-SMA. However, only activation of the pre-SMA differentiated stopping from a high-level baseline that controlled for attentional capture. As expected, unsuccessful attempts at stopping activated the anterior cingulate cortex. In keeping with work in nonhuman primates these findings demonstrate that successful motor inhibition is specifically associated with pre-SMA activation.
authors.affiliation: Division of Experimental Medicine, Imperial College London, London W12 0NN, United Kingdom. david.sharp@imperial.ac.uk
authors.forename: D J
authors.initials: DJ
authors.lastname: Sharp
authors.forename: V
authors.initials: V
authors.lastname: Bonnelle
authors.forename: X
authors.initials: X
authors.lastname: De Boissezon
authors.forename: C F
authors.initials: CF
authors.lastname: Beckmann
authors.forename: S G
authors.initials: SG
authors.lastname: James
authors.forename: M C
authors.initials: MC
authors.lastname: Patel
authors.forename: M A
authors.initials: MA
authors.lastname: Mehta
mesh_terms: D000328:Adult; D001288:Attention / Q000502:physiology*; D005260:Female; D005625:Frontal Lobe / Q000033:anatomy & histology / Q000502:physiology*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D008959:Models, Neurological; D009043:Motor Activity / Q000502:physiology; D009044:Motor Cortex / Q000033:anatomy & histology / Q000502:physiology; D010775:Photic Stimulation; D013647:Task Performance and Analysis; D055815:Young Adult