The pure electrophysiology of stopping.
In the stop-signal task, subjects should withhold their response in a choice reaction time task when a stop-signal, usually a tone, is presented. Successful stops have been associated with event-related potentials (ERPs) featuring a larger frontocentral positivity relative to failed stops. The functional interpretation of this stop-P3 has been disputed, because stop-ERPs are distorted by overlap from ERPs elicited by preceding go-stimuli. We effectively removed confounding potentials with the 'adjacent response filter method (ADJAR)'. Confirming an interpretation in terms of response inhibition, the stop-P3 remained and overlap removal resulted in a more anterior distribution. As a new finding, the N1 was larger on trials with successful stops, which suggests that inhibitory performance at least partly depended on the ability to switch attention to the stop-signal. Finally, the parietal P3 tended to peak earlier for successful than for failed stops. This is in line with the Horse Race Model, which states that faster stop-processes have a higher chance of winning the race against the go-process.
Bekker
Evelijne M
EM
Department of Psychopharmacology, Utrecht University, Sorbonnelaan 16, P.O. Box 80082, 3508 TB Utrecht, The Netherlands. E.M.Bekker@pharm.uu.nl
Kenemans
J Leon
JL
Hoeksma
Marco R
MR
Talsma
Durk
D
Verbaten
Marinus N
MN
D000293:Adolescent; D000328:Adult; D001931:Brain Mapping; D002755:Choice Behavior / Q000502:physiology*; D004569:Electroencephalography / Q000379:methods; D018913:Event-Related Potentials, P300 / Q000502:physiology*; D005260:Female; D006801:Humans; D007266:Inhibition, Psychological; D008297:Male; D010775:Photic Stimulation / Q000379:methods; D011597:Psychomotor Performance; D011930:Reaction Time / Q000502:physiology*