Contrasting effects of adaptation to a visuomotor rotation on explicit and implicit measures of sensory coupling
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We previously investigated sensory coupling of the sensed positions of cursor and hand in a cursor-control task and found differential characteristics of implicit and explicit measures of the bias of sensed hand position toward the position of the cursor. The present study further tested whether adaptation to a visuomotor rotation differentially affects these two measures. Participants made center-out reaching movements to remembered targets while looking at a rotated feedback cursor. After sets of practice trials with constant (adaptation condition) or random (control condition) visuomotor rotations, test trials served to assess sensory coupling. In these trials, participants judged the position of the hand at the end of the center-out movement, and the deviation of these judgments from the physical hand positions served as explicit measure of the bias of sensed hand position toward the position of the cursor, whereas the implicit measure was based on the direction of the return movement. The results showed that inter-individual variability of explicitly assessed biases of sensed hand position toward the cursor position was less in the adaptation condition than in the control condition. Conversely, no such changes were observed for the implicit measure of the bias of sensed hand position, revealing contrasting effects of adaptation on the explicit and implicit measures. These results suggest that biases of explicitly sensed hand position reflect sensory coupling of neural representations that are altered by visuomotor adaptation. In contrast, biases of implicitly sensed hand position reflect sensory coupling of neural representations that are unaffected by adaptation.
This research was supported by the German Research Foundation (DFG) (Grant number Ra 2183/1-3). We thank Maleen Greine and Franziska Schywalski for their support in data collection.
Compliance with ethical standards
This study was funded by the German Research Foundation (DFG) (Grant number Ra 2183/1-3).
Conflict of interest
Miya Rand declares that she has no conflict of interest. Herbert Heuer declares that he has no conflict of interest.
All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards.
Informed consent was obtained from all individual participants included in the study.
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