Protocol for extracellular recordings in the external globus pallidus of the behaving/awake monkey.

Extracellular recordings in behaving animals are useful for establishing associations between neuronal activity and behavior. Here, we describe how to record in the external globus pallidus (GPe) of monkeys engaged in a behavioral task. We detail the stereotaxic surgery for chamber and head-holder implantation, the post-operative MRI scan to ascertain the GPe coordinates and validate the position of the chamber, and the data collection. This protocol makes it possible to examine the electrophysiological features of GPe neurons in behaving monkeys. For complete details on the use and execution of this protocol, please refer to Katabi et al.1.

Subthalamic nucleus input-output dynamics are correlated with Parkinson's burden and treatment efficacy.

The subthalamic nucleus (STN) is pivotal in basal ganglia function in health and disease. Micro-electrode recordings of >25,000 recording sites from 146 Parkinson's patients undergoing deep brain stimulation (DBS) allowed differentiation between subthalamic input, represented by local field potential (LFP), and output, reflected in spike discharge rate (SPK). As with many natural systems, STN neuronal activity exhibits power-law dynamics characterized by the exponent α. We, therefore, dissected STN data into aperiodic and periodic components using the Fitting Oscillations & One Over F (FOOOF) tool. STN LFP showed significantly higher aperiodic exponents than SPK. Additionally, SPK beta oscillations demonstrated a downward frequency shift compared to LFP. Finally, the STN aperiodic and spiking parameters explained a significant fraction of the variance of the burden and treatment efficacy of Parkinson's disease. The unique STN input-output dynamics may clarify its role in Parkinson's physiology and can be utilized in closed-loop DBS therapy.