Ultra-rapid Saccade Adaptation: Effective in Under Three Minutes
56.516, Tuesday, May 14, 2:45 - 6:45 pm, Vista Ballroom
Michael Gray1, Annabelle Blangero1, James Herman1, Mark Harwood1; 1Biology Department, City College of New York
Introduction. Consistent mismatches between saccade landing positions and their intended targets are compensated for by a saccade adaptation process that increases or decreases saccade amplitude to minimize errors. It has been shown that feedback from these errors is most influential within the first 100ms after a saccade. Nonetheless, conventional paradigms involve much longer post-saccadic viewing durations with trials lasting several seconds. Here we propose an efficient and equally effective saccade adaptation paradigm in which subjects make saccades almost continuously, greatly reducing experiment duration while suffering no reduction in adaptation magnitude. Methods. During these Â‘ultra-rapidÂ’ adaptation sessions, subjects (n=7) made horizontal saccades to a red annulus (0.3°), which randomly stepped 10° to the left or right of its previous location ~60ms after a saccade landed. After an initial baseline period, the rapidly stepping target made additional intrasaccadic steps of 2°, inducing inward or outward adaptation depending on the session. Ultra-rapid adaptation sessions were compared to Â‘regularÂ’ adaptation sessions with post-saccadic trial durations of ~1.5sec. Sessions lasted either 250 trials (ultra-rapid: 2.5min; regular: 7min) or 800 trials (7min; 25min), allowing us to compare effects of both trial number and experiment duration on adaptation magnitude. Results. Remarkably, for 250-trial inward adaptation, adaptation magnitude was significantly greater for the ultra-rapid session (t=3.68, p=0.01). Otherwise, there were no significant differences in adaptation magnitude between ultra-rapid and regular paradigms for both inward and outward forms of saccade adaptation when there were equal trial numbers. Conclusions. This novel paradigm provides an extremely time-efficient method for inducing saccade adaptation, which is of potentially great benefit for experiments requiring many trials or examining clinical populations. Our findings also have theoretical implications for the time-dependent mechanisms underlying saccade adaptation and motor learning in general.