Cortico-basal-ganglia communication: Temporally structured activity for selective motor control

Abstract

Despite the hard-wired structural connectivity of neural pathways, neural circuits allow context-dependent reactions to sensory cues by triggering the desired movement. Cortico-basal-ganglia circuits seem particularly important for flexible motor control as this is impaired in Parkinsons disease (PD). We analysed subthalamic nucleus (STN) spike and cortical ECoG activity from PD patients performing a visually-cued hand grip task. Fast reaction times were preceded by enhanced STN spike-to-cortical gamma phase coupling irrespective of firing rate changes, suggesting a role of gamma coupling in motor preparation. STN spike timing was offset by half a cycle when comparing ipsilateral with contralateral movements. Additionally, cortical high-frequency activity increased more steeply within each gamma cycle at the sites that showed the strongest coupling with STN spikes. Cortico-basal-ganglia gamma coupling may thus help shape neural activity to facilitate selective motor control. The observation that this effect occurs independent of changes in mean firing rate has far-reaching implications.\n\nHighlightsO_LIFast RTs were preceded by enhanced STN spike-to-cortical gamma phase coupling\nC_LIO_LISTN spike probability was significantly modulated relative to the gamma cycle\nC_LIO_LIDuring ipsilateral movement, spikes were more likely at the opposite part of the cycle\nC_LIO_LISTN output may thus help shape cortical gamma for selective motor control\nC_LI