Modulation of Rolandic Beta-Band Oscillations during Motor Simulation of Joint Actions.

Mathilde Ménoret,Riitta Hari,Mathieu Bourguignon,Luigi Cattaneo

doi:10.1371/journal.pone.0131655

Abstract

Successful joint actions require precise temporal and spatial coordination between individuals who aim to achieve a common goal. A growing number of behavioral data suggest that to efficiently couple and coordinate a joint task, the actors have to represent both own and the partner’s actions. However it is unclear how the motor system is specifically recruited for joint actions. To find out how the goal and the presence of the partner’s hand can impact the motor activity during joint action, we assessed the functional state of 16 participants’ motor cortex during observation and associated motor imagery of joint actions, individual actions, and non-goal-directed actions performed with either 1 or 2 hands. As an indicator of the functional state of the motor cortex, we used the reactivity of the rolandic magnetoencephalographic (MEG) beta rhythm following median-nerve stimulation. Motor imagery combined with action observation was associated with activation of the observer’s motor cortex, mainly in the hemisphere contralateral to the viewed (and at the same time imagined) hand actions. The motor-cortex involvement was enhanced when the goal of the actions was visible but also, in the ipsilateral hemisphere, when the partner’s hand was visible in the display. During joint action, the partner’s action, in addition to the participant’s own action, thus seems to be represented in the motor cortex so that it can be triggered by the mere presence of an acting hand in the peripersonal space.

Highlights

Joint actions are ubiquitous in our normal social life: we shake hands, carry heavy objects and play games with others
Post-hoc analyzes based on Wilcoxon test revealed that participants reported being statistically significantly more attentive to the videos when the ball was present within the ring than when it was absent (2.1 vs. 2.9; p = 0.003) and that motor imagery was easier when the ball was present than when it was absent (1.7 vs. 2.1; p = 0.036)
Action observation associated with instructed motor imagery was associated with activation of the observer’s primary motor cortex, mainly in the hemisphere contralateral to the viewed and imagined hand movements

Summary

Introduction

Joint actions are ubiquitous in our normal social life: we shake hands, carry heavy objects and play games with others. Such actions are typically easy and natural to perform they require precise temporal and spatial coordination between the partners who aim to achieve a common goal [1]. The mechanisms for planned coordination during complex tasks are still unclear [2,3]. One existing debate concerns the need to share high-level representations and intentions to engage in a joint action [4,5,6,7,8]. A growing number of behavioral data suggest that it may be necessary.

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