An electroencephalographic study of imagined movement

Objective: Determine the generator sources for actual and imagined (simulated) movements of fingers and toes. Design: Observational. Setting: Electroencephalography laboratory. Subjects: Ten asymptomatic adult volunteers. Main Outcome Measure: Comparison of cortical electrical fields and their dipole sources in actual and imagined movements. Results: Cortical electrical fields tend to be contralateral with actual movements and midline with imagined movements. Dipole sources of actual movements include a contralateral contribution from the frontal (primary motor) area. Sources of imagined movements are midline or ipsilateral. Conclusions: (1) The motor networks underlying the generation of actual and imagined movements are different. (2) Imagined movements lack a primary motor area source, but involve medial and ipsilateral structures. (3) The effectiveness of imagined movements in rehabilitation may stem from activation of premotor or supplementary motor areas.