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.

Factors Contributing to Spinal Cord Stimulation Outcomes for Chronic Pain.

OBJECTIVE: Spinal cord stimulation (SCS) has been shown to be a safe and effective therapy for patients with chronic pain. However, some patients do not obtain or maintain adequate pain relief after SCS. The goal of this study was to identify factors that affect patient outcome with regard to SCS. MATERIALS AND METHODS: A retrospective analysis of electronic medical records at a single site was performed. Records for 181 patients who received SCS implants from 2014 through 2016 were collected with follow-up data captured up to August 2019. Patient outcome was measured by device explantation and patient benefit from the SCS. Study parameters included demographic characteristics, history of pain, SCS implant characteristics, and postimplantation events. RESULTS: An earlier diagnosis of radiculopathy was associated with an increased risk of poor benefit (relative risk [RR], 1.81; 95% CI, 1.19-2.74; p = 0.008). Postimplantation falls were associated with an increased risk of poor benefit (RR, 2.17; 95% CI, 1.48-3.17; p = 0.009). Device manufacturer was associated with both patient benefit and explantation. Device 2 was associated with a reduced risk of poor benefit (RR, 0.52; 95% CI, 0.32-0.85; p = 0.009). Device 4 was associated with an increased risk of poor benefit (RR, 1.71; 95% CI, 1.14-2.55; p = 0.02) and increased risk of device explantation (RR, 2.69; 95% CI, 1.2-6.02; p = 0.03). CONCLUSIONS: Patient outcome was associated with diagnosis, postimplantation falls, and device manufacturer. Further investigation is recommended to confirm associations through prospective studies that can more accurately quantify patient outcome over longer periods.