Abstract
Purpose :
The temporal relation of competing visual stimuli may determine the corresponding oculomotor response. In this study we systematically varied the temporal coincidence of two conflicting stimuli and we investigated saccades that were elicited from such stimuli.
Methods :
We varied the time of presentation of two identical spatially separated stimuli between -150ms and +150ms and we measured the amplitude of the saccade elicited by these stimuli using infrared eye tracking. In the first experiment, all stimuli were shown for 25ms only. In the second experiment, stimuli remained on the screen until the subsequent stimulus appeared, while all stimuli were removed after saccade onset in the third experiment.
Results :
We found saccadic averaging if stimuli were presented at intervals up to 75ms, i.e. the saccades landed at an intermediate position. The strongest effect was observed if a stimulus was shown 25ms after or before another stimulus. This led to a strong deviation of the landing point towards the second stimulus. In contrast time intervals longer than 75ms elicited saccade adaptation, i.e. the saccadic landing point gradually moved toward the second location over time.
Conclusions :
The timing of two conflicting stimuli determines whether the saccade is directed at an averaged intermediate position or whether the saccadic amplitude undergoes adaptation.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.