Evaluation of the effective connectivity of the dominant primary motor cortex during bimanual movement using Granger causality.

Granger causality analysis of the whole brain, voxel-by-voxel, was applied to six right-handed subjects performing a classic bimanual movement, to describe the effective connectivity between the activated voxels in the left primary motor cortex (PMC) and other parts of the brain, by choosing the left PMC as a reference region. The results demonstrated that the left and right PMC interact during bimanual movement, and Granger causality mapping implied a possible cause-effect relationship. The supplementary motor area (SMA) and cerebellum were pre-activated during bimanual movement relative to the left PMC, confirming the prior qualitative results concerning the functions of the SMA and cerebellum in hand movements.