Authors: Matthew Heath Jeffrey Weiler Kendall Marriott Timothy N Welsh
Publish Date: 2011/01/06
Volume: 209, Issue: 1, Pages: 117-127
Abstract
Antisaccades require the suppression of a stimulusdriven response ie response suppression and the computation of a movement plan mirrorsymmetrical to the location of a target ie vector inversion The goal of the present study was to determine whether response suppression vector inversion or both contribute to previously reported differences in the online control of pro and antisaccades Heath in Exp Brain Res 203743–752 2010a Pro and antisaccades were completed in separate blocks ie blocked schedule and a block wherein the spatial relation between stimulus and response was provided at response cuing ie random schedule Notably the random schedule provides a relative means for equating response suppression across pro and antisaccades To examine online trajectory amendments we computed the proportion of variance R 2 values explained by the spatial location of the eye at early middle and late stages of saccade trajectories relative to the saccade’s ultimate endpoint The basis for this analysis is that betweentask differences in R 2 magnitudes reflect differences in the use of feedback for online trajectory amendments small R 2 values represent a trajectory supported via online control whereas larger R 2 values reflect a reduction in online control Results show that antisaccades yielded larger R 2 values than prosaccades from early to late stages of saccade trajectories and this finding was observed regardless of whether or not tasks were equated for response suppression Thus we propose that the intentional nature of vector inversion disrupts the normally online control of saccades and renders a mode of control that is not optimized to support errorreducing trajectory amendments
Keywords: