The motor preparation of directionally incompatible movements

This work explores, for the first time, the electro-cortical activity related to the preparation of bimanual incompatible actions. To accomplish this aim, we recorded motor-related cortical potentials (MRCPs) in 16 healthy subjects, who were asked to draw lines and/or circles during three experimental conditions: Unimanual, Bimanually Compatible (either lines or circles with both hands) and Bimanually Incompatible (a line with one hand and a circle with the other hand). We show that the electro-cortical activity recorded during the preparation of the bimanually incompatible actions included a central positivity (CP) that began approximately 2.5s before movement onset and was localized in medial frontal areas. We then recorded a later (ca. 700ms before movement onset) negative activity in the supplementary motor area (consistent with Bereitschaftspotential). Finally, a strong frontal lateral positivity (FLP) emerged ca. 1.8s before the initiation of drawing that was localized in the dorsolateral prefrontal cortex. All components were bilateral. The CP component has not been described before. These data are discussed with regard to the "interference network" theory.