Abstract
Anticipatory smooth eye movements (ASEM) are smooth eye movements in the direction of expected target motion that begin before the onset of target motion or before an expected change in the direction of motion. We investigated the role of different cues in eliciting ASEM, either when the target was viewed passively, or was moved actively.The target was a disc that traveled down an inverted Y-shaped tube. A cue to the horizontal motion path was provided by blocking one branch of the Y with a visible barrier. ASEM in the cued direction were prominent, even from the first trial. Inverting the tube so that the cognitive cue of implied gravity was removed did not diminish ASEM. A non-visual cue, alternating right and left paths, was less effective than the visual cue. The same patterns of ASEM appeared in individuals with Autism Spectrum Disorder.When the motion of the disc within the tube was controlled by the subject’s arm movements (via a mouse), anticipatory movements of the arm occurred, either when the motion path was cued by the visible barrier or was chosen freely. The eye closely followed with little or no lag, but did not lead, the anticipatory arm movements. Pursuit lagged further behind the target when the identical patterns of disc motion produced by the arm were instead tracked passively, showing the contribution of anticipation to smooth pursuit during active tracking. These results show that ASEM can be generated by visual cues to the direction of target motion that are semantically consistent with the scene, or non-visual cues provided by active control of motion. These findings suggest that anticipatory smooth eye movements are valuable for reducing retinal velocity errors, either when viewing natural scenes or during tasks requiring the coordination of hand and eye.
Meeting abstract presented at VSS 2012