Stop-signal response inhibition in schizophrenia: behavioural, event-related potential and functional neuroimaging data.
Inhibitory control deficits are well documented in schizophrenia, supported by impairment in an established measure of response inhibition, the stop-signal reaction time (SSRT). We investigated the neural basis of this impairment by comparing schizophrenia patients and controls matched for age, sex and education on behavioural, functional magnetic resonance imaging (fMRI) and event-related potential (ERP) indices of stop-signal task performance. Compared to controls, patients exhibited slower SSRT and reduced right inferior frontal gyrus (rIFG) activation, but rIFG activation correlated with SSRT in both groups. Go stimulus and stop-signal ERP components (N1/P3) were smaller in patients, but the peak latencies of stop-signal N1 and P3 were also delayed in patients, indicating impairment early in stop-signal processing. Additionally, response-locked lateralised readiness potentials indicated response preparation was prolonged in patients. An inability to engage rIFG may predicate slowed inhibition in patients, however multiple spatiotemporal irregularities in the networks underpinning stop-signal task performance may contribute to this deficit.
Brain and Psychological Sciences Centre, Swinburne University of Technology, Melbourne, VIC, Australia. matthewhughes@swin.edu.au
Matthew Edward
ME
Hughes
William Ross
WR
Fulham
Patrick James
PJ
Johnston
Patricia Therese
PT
Michie
D000328:Adult; D000704:Analysis of Variance; D001921:Brain / Q000098:blood supply / Q000473:pathology / Q000503:physiopathology; D001931:Brain Mapping; D004569:Electroencephalography; D005071:Evoked Potentials / Q000502:physiology*; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007266:Inhibition, Psychological; D008279:Magnetic Resonance Imaging; D008297:Male; D009483:Neuropsychological Tests; D010100:Oxygen / Q000097:blood; D011930:Reaction Time; D012559:Schizophrenia / Q000150:complications* / Q000473:pathology*; D012565:Schizophrenic Psychology; D017603:Signal Detection, Psychological / Q000502:physiology*
D010100:Oxygen