Abstract
The sudden appearance of a visual distractor can briefly, but powerfully, inhibits saccades (Reingold and Stampe, 2002). However, this inhibitory influence of distractors may by habituation with repeated distractor presentation at a single retinotopic location, or by a more spatially general dampening of inhibition, occurring when distractors appear at a high frequency at any location in the visual field. Indeed, such a spatially generalized mechanism could be useful during behavior in highly dynamic visual environments. We examined these possibilities by recording the eye movements of 2 subjects in tasks that required the execution of saccades in the face of visual distractors. Eye movements were recorded at 500 Hz (Eyelink II, SR Research). Trials began with central fixation. A 1° square was flashed (250 ms) 10° to the left or right. 700-1000 ms later, fixation point disappearance (“go” signal) cued saccade initiation. Subjects were instructed to make a saccade to the target’s remembered location. There were 4 experimental tasks: 1) no distractor; 2) single distractor appearing soon after go signal, opposite the remembered target; 3) 3 distractors at 200 ms intervals at a single location opposite the remembered target; 4) three distractors at 200 ms intervals at three separate locations distant from the remembered target, with the final distractor appearing opposite the remembered target. As in previous experiments (Edelman and Xu, 2009) we found strong inhibition in Task 2. Saccade inhibition was virtually eliminated in Task 3. In Task 4, saccade inhibition was intermediate to that of Tasks 2 and 3. These results suggest that stimulus repetition at a single location strongly ameliorates saccade inhibition, but that a more spatially generalized amelioration mechanism for repeated distractor presentation also exists. Supported by NCRR 2G12RR03060-26A1, NIMHHD 8G12MD007603-27
Meeting abstract presented at VSS 2015