The kinematics of motor imagery: comparing the dynamics of real and virtual movements.

Motor imagery (MI) is a key tool for studying the cognitive functions of movement. These studies assume that movements and their MI (virtual movements) involve the same cognitive functions. The real-virtual isochrony and isometry of movements of different complexity and accuracy, and the kinematics of real and virtual movements (real-virtual spatial homology and partial isometry) were studied to test this hypothesis. Isochrony was high in complex attention-demanding tasks but not in simple or inaccurate tasks, with isometry and spatial homology also being different for different motor patterns. These data suggest that movements and their MI do not always involve the same cognitive functions, and are particularly different in simple motor tasks requiring low attention levels.