Does saccadic adaptation transfer to non-adapted pointing movements?


Previous research has suggested that saccadic adaptation may transfer to the manual system. This has implications for adaptation studies using a target jump paradigm where both the moving eyes and limbs are exposed to the visual perturbation. Although various studies have shown this potential transfer, methodological differences such as the use of short target distances, or only backward target jumps may limit generalization. For example, saccadic adaptation to backward and forward jumps may occur through different mechanisms, limiting conclusions about adaptation during forward jumps. The purpose of this study was to examine if amplitude adaptation occurs in saccades to forward target jumps, and if so, whether the adaptation influences pointing movements. Participants (n=20) looked and pointed to targets presented ~19° in the periphery. Saccades were monitored with use of EOG and pointing movements were measured via motion capture. A pre-post design was used to compare saccade and pointing amplitudes before and after an exposure block consisting of look-only trials. The control group looked to stationary targets during the exposure block, and the experimental group looked to targets that jumped ~3° during the saccade. Our results showed little difference in mean saccade amplitudes between pre- and post-exposure blocks during forward target jumps. Not surprisingly, there were also no pre-post differences in pointing amplitudes. This leads us to question whether concurrent look and point movements in response to forward target jumps in our task context are necessary to elicit adaptation in either saccade or manual system.