Citation

Dimoska A, Johnstone SJ. Biol. Psychol. 2008; 77(3): 324-336.

Affiliation

Department of Psychology and the Brain&Behaviour Research Institute, University of Wollongong, Northfields Avenue, Wollongong, NSW 2522, Australia. adimoska@med.usyd.edu.au

Copyright

(Copyright © 2008, Elsevier Publishing)

DOI

10.1016/j.biopsycho.2007.11.005

PMID

18096294

Abstract

The aim of the present study was to determine whether ERP modulations associated with varying the probability of the stop-signal in the stop-signal task reflect variations in inhibitory processing, or whether they simply reflect general arousal associated with novel stimuli. This was achieved by examining the effects of probability on a control"ignore-signal"stimulus in addition to the stop-signal. ERP findings revealed large fronto-central N1 and P3 components that were larger in amplitude for stop-signals than ignore-signals, and when stimuli were rare (30%) compared to frequent (70%). However, probability effects were not greater for stop-signals compared to ignore-signals, discounting an interpretation exclusively in line with inhibitory processing. A principal components analysis (PCA) revealed a slow-wave ERP component that partially accounted for these probability effects. Together, the present findings indicate that ERP differences between rare and frequent stop-signals did not primarily reflect varying inhibitory requirements, but rather may be confounded by novelty effects.

Language: en