Probing the involvement of the earliest levels of cortical processing in motion extrapolation with rapid forms of visual motion priming and adaptation.

In this study, we investigated the effect of brief motion priming and adaptation, occurring at the earliest levels of the cortical visual stream, on time-to-contact (TTC) estimation of a target passing behind an occluder. By using different exposure times of directional motion presented in the occluder area prior to the target's disappearance behind it, our aim was to modulate (prime or adapt) the extrapolated motion of the invisible target, thus producing different TTC estimates. Our results showed that longer (yet subsecond) exposures to motion in the same direction as the target produced late TTC estimates, whereas shorter exposures produced shorter TTC estimates, indicating that rapid forms of motion adaptation and motion priming affect extrapolated motion. Our findings suggest that motion extrapolation might occur at the earliest levels of cortical processing of motion, at which these rapid mechanisms of priming and adaptation take place.