Causative role of left aIPS in coding shared goals during complementary joint actions: studies combining motion capture and TMS.

Successful interpersonal coordination requires that two or more agents synchronize and adapt to each other’s movements. Behavioral studies suggest that performing effective complementary (i.e. non-imitative) actions like for example “passing an object” implies the sharing of a common overarching goal (e.g. passing the object from one person to the other), which in turn depends on the achievement of two different sub-goals, each specific for each co-agent (e.g. handing/receiving). However, much less is known about the neurocognitive bases of “shared goal” representation during realistic complementary interactions. In three experiments, we combined off-line inhibitory Transcranial Magnetic Stimulation and motion capture analyses to investigate the causal role of two key motor regions (left anterior Intra-Parietal Sulcus, aIPS, ventral Premotor Cortex, vPM) in supporting the ability to perform complementary interactions with a virtual partner. Results showed that only aIPS (and not vPM o