Involuntary Feedback Responses Reflect a Representation of a Partner During Jointly Coordinated Actions

Our lives are enriched when we coordinate our actions with others, such as dancing with a partner. Past work has suggested that humans form neural representations of a partner’s actions. Yet it is unclear whether rapid feedback responses will reflect a representation of our partner during jointly coordinated movements. Here we tested the idea that involuntary visuomotor circuits have a representation of both self and partner. To investigate, human pairs performed goal-directed reaches by moving a jointly controlled cursor. Participants observed both their own self target and their partner’s target. We manipulated the width of both the self and partner target to be either relevant (short width) or irrelevant (long width). The self-target center was aligned with the partner target center. Participants were instructed to move and stabilize the jointly controlled cursor in their self-target within a time constraint. We had four experimental conditions: partner-relevant/self-relevant, partner-irrelevant/self-relevant, partner-relevant/self-irrelevant, partner-irrelevant/self-irrelevant. On a subset of trials, each participant’s hand was constrained within a force channel when the jointly controlled cursor jumped laterally and then back to the original path. We measured the lateral force applied to the channel during the involuntary visuomotor feedback response epoch (180-230 ms). Participants displayed significantly greater involuntary visuomotor feedback responses in the partner-relevant/self-irrelevant condition compared to the partner-irrelevant/self-irrelevant condition (p