Poster B125, Sunday, March 25, 8:00-10:00 am, Exhibit Hall C
Separating Inhibitory and Attentional Neural Signals in the Stop-Signal Paradigm
Darcy Waller1, Jan Wessel1; 1University of Iowa
Introduction: A common paradigm in the field of cognitive science, the stop-signal task (SST) elicits prepotent motor inhibition in the laboratory setting. While most research that utilizes this task stresses inhibitory processes, other factors may contribute to task performance and successful motor inhibition. Here, we disentangle these neural processes using independent component analysis (ICA) of EEG data collected during the SST and a novel non-inhibition task. Methods: Eighteen participants participated in data collection. EEG recording was conducted while participants completed a novel visual task and SST. The new task is similar to the SST in the first visual stimuli presented (a fixation cross followed by a black arrow on all trials), but displays a second, red arrow during every trial and has participants respond with a button press when the red arrow appears so that no inhibition is initiated. Results: Two independent processes were elicited time-locked to the stop signal. The stopping P3 component (an index of inhibition) was significantly active during the SST but not the novel task. Another independent component occurred ~300ms following the stop signal that was not related to inhibition. Onset of both components correlated significantly with stop-signal reaction time. Conclusions: We found that both inhibitory and non-inhibitory neural signals active during the SST contribute significantly to task performance. Though the SST is an excellent paradigm for studying motor inhibition, it is necessary to consider effects of non-inhibition processes, especially when using the SST to study populations in which deficits are not constrained to motor inhibition.
Topic Area: EXECUTIVE PROCESSES: Monitoring & inhibitory control