Joint-Action Coordination of Redundant Force Contributions in a Virtual Lifting Task

Abstract

In this study we investigated redundancy control in joint action. Ten participantpairs (dyads) performed a virtuallifting task in which isometric forces needed to be generated witb two or fom hands. The participants were not allowed to communicate but received continuous visual feedback of their performance. When the task had to be performed with fom hands, participants were confronted with a redundant situation and between-hand force synergies could, in principle, be formed. Performance timing, success rates, cross-correlations, and relative phase analyses oftbe force-time functions were scrutinized to analyze such task-dependent synergies. The results show tbat even though the dyads performed the task slower and less synchronized in tbe joint than in the solo conditions, the success rates in these conditions were identical. Moreover, correlation and relative phase analyses demonstrated that, as expected, tbe dyads formed between-participant synergies that were indicative of force sharing in redundant task conditions.

Anatomical substrates of cooperative joint-action in a continuous motor task: Virtual lifting and balancing

“…The primary goal of the current experiment was to determine the involvement of the human MNS in a previously reported (Bosga and Meulenbroek, 2007) continuous joint-action task involving lifting and balancing a bar. Based on the hypothesis that joint action involves simulating the actions of one's partner, we predicted that brain areas thought to support simulation (IFG, IPL) would be more active in the joint conditions than in the solo condition.…”

“…Based on the hypothesis that joint action involves simulating the actions of one's partner, we predicted that brain areas thought to support simulation (IFG, IPL) would be more active in the joint conditions than in the solo condition. Furthermore, because the non-isomorphic joint-action condition requires such a strong complementary dependency as compared to the isomorphic condition (Bosga and Meulenbroek, 2007), we predicted that patterns of brain activation observed during these two joint-action conditions would differ. Based on previous experiments indicating the involvement of the right anterior node of the MNS in complementary actions, we predicted activity at this site would, in the current experiment, be greatest in the joint-action conditions, with relatively greater activity for conditions in which generation of complementary actions was particularly important (NewmanNorlund et al, 2007a).…”

“…Specifically, simulation of others' actions may allow us to predict the immediate goals of a co-actor, and modify our own action plans to ensure execution of an appropriate reactions. In a recent behavioral experiment conducted by Bosga and Meulenbroek (2007), participants lifted and balanced (horizontally) a virtual bar in a target zone either alone or together with a partner. Analysis of data from this experiment revealed that, when cooperating individuals were in control of both ends of the bar (isomorphic balancing), they generated coordinated response trains during bar balancing with each lifter effectively compensating for anticipated bar orientation errors introduced by the other's actions.…”

“…In order to asses the role of the MNS in actions performed alone or with a partner, we scanned participants while they performed a visual-motor balancing task either alone or cooperatively in one of two joint-action configurations used in a previous behavioral experiment (Bosga and Meulenbroek, 2007). In our task, participants utilized force pads to lift a bar to a goal area while balancing a ball in the middle.…”

Motor control hierarchy in joint action that involves bimanual force production

“…For example, Bosga and Meulenbroek (2007) asked pairs of participants to perform a virtual lifting task using constant uni-or bimanual isometric force, although they did not examine the hierarchical relation between bimanual and joint actions. The forces produced by the two participants were negatively correlated when visual feedback of their forces was available, indicating the use of complementary forces to control a virtual bar.…”