Premotor function in interpersonal bimanual coordination: Neural responses to varying frequencies and spatio-temporal...

Interpersonal movement coordination is an important aspect of daily life. Behavioral studies have found that rhythmic bimanual coordination of movement is mainly influenced by two factors, spatio-temporal relationship and frequency of movements. How these factors affect action coordination at the neural level needs further exploration. The current study used a factor design to investigate the brain basis of movement coordination under various spatiotemporal relationships and frequencies, as well as their intricate interaction.

Participants were asked to perform symmetric or alternating hand movements under conditions of different spatio-temporal relationships (symmetric, alternating) and frequencies. A multi-channel, continuous wave, functional near-infrared spectral (fNIRS) imaging instrument was used to monitor hemodynamic activity while 16 pairs of volunteers performed the task.

Behaviorally, as indexed by phase locking value, movements were more stable in symmetric mode than in alternate mode. With increasing frequency, symmetric mode became more unstable; in contrast, alternating mode became more stable at higher frequencies, suggesting phase transition. Activation in brain regions of interest was much stronger in symmetric mode as compared with alternate mode. In alternate mode, but not symmetric mode, [HbO] varied with frequency.

Interpersonal bimanual coordination involves activity in premotor areas (premotor cortex, supplementary motor area, and frontal eye fields). More oxygen is consumed in these regions in alternating mode than in symmetric mode.