Cognitive Neural Mechanisms Of Interpersonal Stepping

It is an innate human ability to coordinate one’s own movements with others to maintain synchronization,A steady state of movement phase and frequency for two or more people is called synchronization.Most previous studies have focused on interpersonal synchronization of pairs of single limbs/objects presenting 0° and 180°phases,and less on bilateral limb synchronization.In the present study,a new stepping task was set up based on previous studies,and two experiments were conducted to compare the behavioral performance and neural characteristics of different stepping tasks in side-by-side and face-to-face positions,respectively,to understand the cognitive neural mechanisms of interpersonal stepping.Experiment 1 required two subjects to perform three stepping tasks side-by-side:stepping alone,parallel mode(synchronized movements of legs corresponding to body structures)and symmetrical mode(synchronized movements of legs with mirror symmetry).Behavioral results showed that internal coordination was consistent in parallel and symmetrical modes and in stepping along,and inter-individual coordination did not differ significantly in parallel and symmetrical modes.Neural results showed that neural activation in the bilateral inferior parietal lobe was stronger for stepping along than for parallel and symmetrical modes,and no differences were found between the three tasks for interbrain neural synchronization.Experiment 2 changed the spatial position of the interacting parties to amplify the visual differences between the two interpersonal stepping modes and required two subjects to face each other to perform the stepping tasks in stepping along,parallel and symmetrical modes.Behavioral results showed that internal coordination did not differ across the three tasks,although inter-individual coordination performed better in the symmetrical mode than in the parallel mode.Neural results showed that neural activation levels were significantly higher in stepping along than in parallel and symmetrical modes,while interbrain neural synchronization was significantly higher in parallel and symmetrical modes than in stepping along.The above results suggest that(1)performing parallel and symmetrical modes has lower activation in frontoparietal regions than stepping along,and interpersonal stepping may be easier to coordinate and stabilize than stepping along;(2)no differences in activation and interbrain synchrony were detected between parallel and symmetrical modes,and parallel and symmetrical modes may consume the same cognitive resources;(3)compared with stepping along,face-to-face symmetrical and parallel modes of interbrain neural synchrony was stronger,which may underlie the neural basis of faceto-face interpersonal stepping.