Involuntary cueing effects during smooth pursuit: facilitation and inhibition of return in oculocentric coordinates

Abstract

Peripheral cues induce facilitation with short cue-target intervals and inhibition of return (IOR) with long cue-target intervals. Modulations of facilitation and IOR by continuous displacements of the eye or the cued stimuli are poorly understood. Previously, the retinal coordinates of the cued location were changed by saccadic or smooth pursuit eye movements during the cue-target interval. In contrast, we probed the relevant coordinates for facilitation and IOR by orthogonally varying object motion (stationary, moving) and eye movement (fixation, smooth pursuit). In the pursuit conditions, cue and target were presented during the ongoing eye movement and observers made a saccade to the target. Importantly, we found facilitation and IOR of similar size during smooth pursuit and fixation. The results suggest that involuntary orienting is possible even when attention has to be allocated to the moving target during smooth pursuit. Comparison of conditions with stabilized and moving objects suggest an oculocentric basis for facilitation as well as inhibition. Facilitation and IOR were reduced with objects that moved on the retina both with smooth pursuit and eye fixation.