Microscale electrophysiological functional connectivity in human cortico-basal ganglia network

Objective: We investigated the electrophysiological relationships in the cortico-basal ganglia network on a sub-centimeter scale to increase our understanding of neural functional relationships in Parkinson's disease (PD). Methods: Data was intraoperatively recorded from 2 sources in the human brain—a microelectrode in the subthalamic nucleus (STN) and a micro-electrocorticography grid on the motor association cortex—during bilateral deep brain stimulation (DBS) electrode placement. STN neurons and local field potential (LFP) were defined as functionally connected when the 99.7% confidence intervals of the action potential (AP)-aligned average LFP and control did not overlap. Results: APs from STN neurons were functionally connected to the STN LFP for 18/46 STN neurons. This functional connection was observed between STN neuron APs and cortical LFP for 25/46 STN neurons. The cortical patterns of electrophysiological functional connectivity differed for each neuron. Conclusions: A subset of single neurons in the STN exhibited functional connectivity with electrophysiological activity in the STN and at a distance with the motor association cortex surveyed on a sub-centimeter spatial scale. These connections show a per neuron differential topography on the cortex. Significance: The cortico-basal ganglia circuit is organized on a sub-centimeter scale, and plays an important role in the mechanisms of PD and DBS.