Motor cortex stimulation ameliorates parkinsonian locomotor deficits: effectual and mechanistic differences from subthalamic modulation.

Subthalamic deep brain stimulation (STN DBS) has been a therapeutic choice for Parkinson's disease (PD). We found that epidural motor cortex stimulation (MCS) with sustained positive (hyperpolarizing) currents could also consistently ameliorate the locomotor deficits in parkinsonian animals, rectifying the pathological paucity in both discharging unit varieties and movement-dependent spatiotemporal activity pattern changes in motor cortex (MC). Mechanistically, MCS hyperpolarizes both glutamatergic pyramidal neurons (PN) and GABAergic interneurons (IN) and consequently partly relieves PN from IN's control.