Together, these results suggest that general fluctuations in eye velocity as well as retinal error signals are related to oculomotor behavior in subsequent trials. The direction of the observed effect contradicts the expectations based on perceived speed and eye velocity, but can be predicted by a combination of retinal velocity and position error signals.
Matlab 2019a purepursuit trial#
When comparing the same physical prior trials but tracked with additional corrective saccades, the eye velocity in the test trial also differed systematically (slower for forward saccades, and faster for backward saccades). Although there were also differences in eye velocity across the different manipulations, they could not explain the observed reliability-weighted integration. When the prior trials differed in starting position, significant effects on subsequent oculomotor behavior were only observed for the reliable target. When the velocity of prior trials differed from test trials, the reliability-weighted integration of prior information was replicated. Additionally, these prior targets could vary in terms of contrast to manipulate reliability. Earlier in the sequence, the prior was manipulated by presenting targets that either had different velocities, different starting positions, or target movements designed to elicit differential oculomotor behavior (tracked with or without additional corrective saccades).
To test for this, participants viewed movement sequences that all ended with the same test trial. The present study extended this research by investigating the roles of different retinal or extra-retinal signals for this process. The oculomotor system makes use of an integration of previous stimulus velocities (the prior) and current sensory inputs to adjust initial eye speeds.