Eye movements do not play an important role in the adaptation of hand tracking to a visuomotor rotation

Abstract

Gouirand N, Mathew J, Brenner E, Danion FR. Eye movements do not play an important role in the adaptation of hand tracking to a visuomotor rotation. Adapting hand movements to changes in our body or the environment is essential for skilled motor behavior. Although eye movements are known to assist hand movement control, how eye movements might contribute to the adaptation of hand movements remains largely unexplored. To determine to what extent eye movements contribute to visuomotor adaptation of hand tracking, participants were asked to track a visual target that followed an unpredictable trajectory with a cursor using a joystick. During blocks of trials, participants were either allowed to look wherever they liked or required to fixate a cross at the center of the screen. Eye movements were tracked to ensure gaze fixation as well as to examine free gaze behavior. The cursor initially responded normally to the joystick, but after several trials, the direction in which it responded was rotated by 90°. Although fixating the eyes had a detrimental influence on hand tracking performance, participants exhibited a rather similar time course of adaptation to rotated visual feedback in the gaze-fixed and gaze-free conditions. More importantly, there was extensive transfer of adaptation between the gazefixed and gaze-free conditions. We conclude that although eye movements are relevant for the online control of hand tracking, they do not play an important role in the visuomotor adaptation of such tracking. These results suggest that participants do not adapt by changing the mapping between eye and hand movements, but rather by changing the mapping between hand movements and the cursor's motion independently of eye movements.NEW & NOTEWORTHY Eye movements assist hand movements in everyday activities, but their contribution to visuomotor adaptation remains largely unknown. We compared adaptation of hand tracking under free gaze and fixed gaze. Although our results confirm that following the target with the eyes increases the accuracy of hand movements, they unexpectedly demonstrate that gaze fixation does not hinder adaptation. These results suggest that eye movements have distinct contributions for online control and visuomotor adaptation of hand movements.

Gaze behavior during visuomotor tracking with complex hand-cursor dynamics

“…Overall, those observations suggest that participants employed a rather robust gaze strategy that consists of positioning gaze between cursor and target but closer to the target. Although similar findings were observed when participants perform this tracking task with a joystick and a rotated cursor (Gouirand et al, 2019), the current study demonstrates that this strategy (gaze on target first) holds for more complex mappings and full arm movements.…”

“…When people perform full arm movements under a simple (one-to-one) hand-cursor relationship, their gaze is much closer to the target than the cursor (Danion & Flanagan, 2018), suggesting that an estimate of cursor position is accessible through peripheral vision and/or arm (efferent/afferent) signals. We recently showed that when participants track a moving target with a joystick, their gaze is also closer to the target than the cursor after adapting to a visuomotor rotation that rotates the cursor away from the hand but preserves a one-to-one mapping between cursor speed and hand speed (Gouirand et al, 2019). The goal of the current study was to determine whether fixating the target with the eyes is a gaze strategy that extends to full arm movements performed under more complex (nonlinear) hand-cursor mappings.…”

Sex differences in visuomotor tracking

“…However, these analyses revealed no key difference between male and female participants. Although no explicit instruction was given regarding eye movements, as expected gaze was mainly directed to target motion 20,29 . Examining how close the gaze was from the target revealed no obvious sex differences.…”

“…Although there is a clear consensus for a male advantage in throwing [13][14][15] , some evidence for a male advantage in visuomotor tracking have been reported [16][17][18][19] but they remain scarce and speak for further confirmation. Our primary objective was therefore to explore the robustness of sex difference in visuomotor tracking by taking advantage of a large dataset that was previously collected in our lab [20][21][22] . More important, we aimed at seeking for the mechanism underlying sex differences.…”

Looking away from a moving target does not disrupt the way in which the movement toward the target is guided

“…In that case, the hand movements toward moving targets were adjusted to the delay in the trial in question, despite the delays being interleaved so that participants could not adapt to them. When participants look at a moving target while moving a delayed cursor toward it (Cámara et al, 2018) or while trying to track it with a cursor (Gouirand, Mathew, Brenner, & Danion, 2019), they must be using peripheral vision to guide the ongoing movement of the hand.…”