Abstract
In order to execute a correct eye movement to a target in a search display, a saccade program towards the target element must be activated while saccade programs towards distracting elements must be inhibited. The aim of the present study was to elucidate the role of the frontal eye field (FEF) in oculomotor competition. fMRI guided transcranial magnetic stimulation (TMS) was administered over the left FEF, the right FEF or the vertex (control site) at three time intervals after target presentation, while subjects performed an oculomotor capture task. When TMS was applied over the FEF contralateral to the visual field where the target was presented, less interference was observed from an ipsilateral distractor compared to stimulation of the FEF ipsilateral to the target’s visual field or stimulation of the vertex. Furthermore, TMS over the FEF contralateral to the visual field of the target decreased saccade latencies to the target, whereas contralateral distractor-oriented saccades were not affected. These findings elucidate the role of the FEF in oculomotor competition by showing that TMS over the FEF does not enhance the selection of a contralateral stimulus-directed saccade per se, but specifically enhances the activation of a contralateral saccade towards a pre-instructed target.
Meeting abstract presented at VSS 2012