Modified sensory feedback enhances the sense of agency during continuous body movements in virtual reality

Kei Aoyagi,Qi An,Yusuke Tamura,Wen Wen,Hajime Asama,Hiroshi Yamakawa,Shunsuke Hamasaki,Atsushi Yamashita

doi:10.1038/s41598-021-82154-y

Kei Aoyagi, Qi An + Show 6 more

Open Access

https://doi.org/10.1038/s41598-021-82154-y

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Abstract

The sense of agency refers to the feeling of control over one’s own actions, and through them, the external events. This study examined the effect of modified visual feedback on the sense of agency over one’s body movements using virtual reality in healthy individuals whose motor control was disturbed. Participants moved a virtual object using their right hand to trace a trajectory (Experiment 1) or a leading target (Experiment 2). Their motor control was disturbed by a delay in visual feedback (Experiment 1) or a 1-kg weight attached to their wrist (Experiment 2). In the offset conditions, the virtual object was presented at the median point between the desired position and the participants’ actual hand position. In both experiments, participants reported improved sense of agency in the offset condition compared to the aligned condition where the visual feedback reflected their actual body movements, despite their motion being less precise in the offset condition. The results show that sense of agency can be enhanced by modifying feedback to motor tasks according to the goal of the task, even when visual feedback is discrepant from the actual body movements. The present study sheds light on the possibility of artificially enhancing body agency to improve voluntary motor control.

Highlights

The sense of agency refers to the feeling of control over one’s own actions, and through them, the external events
The results supported the hypothesis by showing improved agency ratings in the offset condition, even when the actual motion error was larger in the offset condition compared to the aligned condition
The results indicated the possibility of artificially improving the sense of agency during continuous body movements by slightly modifying visual feedback

Summary

Introduction

The sense of agency refers to the feeling of control over one’s own actions, and through them, the external events. The present study sheds light on the possibility of artificially enhancing body agency to improve voluntary motor control When individuals navigate their physical environments, they experience a sense of control over their actions, and through that, over the external events. After stroke, many patients suffer from motor disabilities such as apraxia and hemiparetic/-plegic limbs, and report abnormal self-awareness of action[16,21,22] This is probably because patients’ internal model for controlling their own body remains at the old state before the impairment, and large prediction errors arise when they try to execute an action. If this hypothesis is valid, it means that external modification of sensory feedback may be a useful way to enhance body agency, and potentially benefit voluntary motor learning for people with motor disabilities

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