Abstract
Saccades are predominantly planned in a gaze-centered coordinate system, whereas, reaching movements mainly rely on a body-centered coordinate system. Previous research has shown that saccades and reaching movements are influenced by visual and tactile distractors. In the majority of studies movement targets were presented in the visual modality. For example, saccades towards a visual target curve away more from visual than tactile distractors. However, it is unclear whether this is due to an overlap in the target and the distractor modality or an overlap in the distractor modality and the effector-specific coordinate system. In our study we asked the question whether saccades and reaches are differentially influenced by visual distractors when moving to a visual target and, similarly, whether they are differentially influenced by tactile distractors when moving to a tactile target. The experiment consisted of 4 tasks, performed in separate blocks. Participants had to reach or saccade towards either a tactile or a visual target. A visual or tactile distractor in the modality of the target was presented 350-600ms after the target, serving as a go-signal. In the tactile task, vibrotactile stimulation was applied to the index, middle, and ring finger of the left hand. In the visual task, visual stimuli were presented at the same location as in the tactile task. The target was always vertical above fixation with the distractors located left or right of the target. We found differential effects on movement parameters (curvature and endpoint deviation) of eye and hand movements depending on target/distractor modality. Our results indicate that the strength of distractor inhibition during movement planning depends on the overlap in the distractor modality and the effector-specific coordinate system.
Meeting abstract presented at VSS 2018