Abstract
Studies of saccadic adaptation have primarily focused on manipulations in the spatial dimension. Shifting the location of the saccade target midflight leads to changes in the motor command (e.g. saccade amplitude) and affects subsequent perceptual judgments (e.g. localization). Surprisingly, significant gain reduction has been reported even when the shifted target is presented at post-saccade delays of up to 400ms (Shafer, Noto, & Fuchs 2000). Recent experiments manipulating only the temporal dimension, the delay between saccade landing and target presentation, have demonstrated changes in saccade peak velocity (Shadmehr, Orban de Xivry, Xu-Wilson, & Shih 2010). The current study investigates whether adapting to these artificially induced delays leads to temporal recalibration between action and effect. We test for recalibration using three behavioral tasks: sensorimotor synchronization, temporal order judgements, and duration comparisons. Evidence supporting saccadic temporal recalibration was found in all three experiments. Adapting to delayed feedback corresponded with shifts in saccade synchronization performance, a reversal in the perceived order of action and effect, and duration overestimation for visual stimuli presented at delays after saccade landing. The recalibration depended on the predictability of the visual effects and their temporal proximity to the end of the saccade. The results offer novel insight into the mechanisms underlying perceptual stability and link saccades to the more general phenomenon of motor-sensory recalibration.
Meeting abstract presented at VSS 2018