The role of spatial attention on motor resonance: the case of complementary actions

A large body of evidence indicates that observing actions can activate corresponding motor representations in the observer’s brain. However, studies from our laboratory recently demonstrated that in interactive social contexts this imitative tendency could turn into readiness to perform a dissimilar complementary action. It is currently believed that the observation-execution matching process occurs relatively automatically with no need for top-down control. Nevertheless, the automaticity of the visuomotor transformation process has been poorly investigated. The aim of the present study was to clarify the role of spatial attention during the shift from motor resonance to reciprocity. Single-pulse Transcranial Magnetic Stimulation (TMS) was used to assess corticospinal excitability facilitation while participants observed actions sequences evoking imitative or complementary movements. The allocation of exogenous spatial attention was manipulated by means of a colored cue. Results showed that motor facilitation during the observation of social and non-social actions can be modulated by attention’s allocation. The present finding suggests that attention seems to have a key role during social interactions, enabling our motor system to resonate just for actions that are relevant to our goals.