EEG features of the interaction between sense of agency and body ownership: a motor imagery BCI case study

The sense of body ownership, i.e., the experience of one's body as one's own, and the sense of agency, i.e., the feeling of control over bodily actions, are essential for bodily self-consciousness. Research on EEG-based brain-computer interface (BCI) has shown that individuals can retain a sense of agency and ownership even when they control virtual arms by imaging the movement but without physically performing it. Here, we investigated (i) if we are more accurate in controlling the movement of a virtual device qualified as part of one's own body and (ii) to what extent the EEG feature linked to the agency for one's own body parts and for external device differ. To this aim, participants use an EEGbased BCI to control two virtual arms presented either in a first-person perspective to induce both a sense of ownership and agency over the virtual arms, or in an anatomical incongruent position to retain only the sense of agency. Preliminary data (n=4) showed that there is no difference in the accuracy in controlling the virtual arms in the two conditions, as measured by the EEG decoding algorithm reflecting the motor intention of the user. Crucially, both conditions elicit a sense of agency over the virtual arms, although the sense of ownership was present only in the first-person perspective condition. If confirmed in the remaining participants to be tested (n=34), these results will suggest that the ability of controlling a virtual device is not affected by the sense of ownership felt over it. Therefore, motor control's accuracy and the subsequent sense of agency are the consequences of the association between an internal volitional signal and the external outcome, bypassing the actual body movements and the sense of body ownership. We provide a unique window into the relation between motor control and the sense of body ownership-findings that have important implications for daily life support of patients using neuroprosthetics.