Abstract
Introduction: People are better at performing sequential movements to remembered targets that possess spatial structure (Fagot and De Lillo, 2011). This structure can be acquired at once (E.g., if shown 4 dots that form a square simultaneously) or over time (if the 4 dots are shown one at a time). This study investigates how the temporal presentation of spatial structure affects the ability to perform sequential saccades, reaches, and coordinated saccades & reaches. Methods: 8 head-fixed subjects in a dark room were positioned in front of a 5X5 LED display that encompassed 20° of visual space horizontally and vertically. While maintaining fixation on the central LED, 3-6 peripheral LEDs were illuminated sequentially in one of three ways: 1) The LEDs formed a connected structure and were presented temporally in a "connect the dots" temporal order (spatio-temporal structure congruent), 2) The LEDs had the same spatial structure, but were presented temporally randomly (spatio-temporal structure incongruent), or 3) LED locations were random (unstructured). LEDs then extinguished and subjects performed sequential movements to the remembered locations of the targets in the order they were presented. Results: To date, the saccade data has been collected with the following preliminary analysis. For the spatio-temporal structure incongruent and unstructured conditions, there were more saccades to incorrect target locations and trials with at least one saccade error when only 3 saccades had to be performed versus 6. This was not seen in the spatio-temporal structure congruent condition. In the 6 saccade condition, subjects were less likely to make a saccade error on the 4th or 5th saccades in the spatio-temporal structure congruent condition as compared to the other 2 conditions. Conclusion: Presenting targets that are spatio-temporally congruent reduces saccade errors. We are currently collecting reaching data on this paradigm to investigate if these results are effector specific.
Meeting abstract presented at VSS 2014