Electrophysiological localization of the subthalamic nucleus in parkinsonian patients

Deep brain stimulation of the subthalamic nucleus (STN) is becoming the procedure of choice to reduce symptoms of Parkinson's disease such as rigidity, akinesia and tremor. We present here a series of electrophysiological recordings performed in 34 patients along a standardized electrode trajectory. Neuronal activity along the trajectory consists of a first heterogeneous population of thalamic cells with a mean frequency of 24.8 +/- 1.4 Hz followed by a silent zone and a second population of STN neurones with a significantly higher spiking frequency (P < 0.001) of 42.3 +/- 1.8 Hz. This study confirms previous findings and suggests that rapid measurement of neuronal spiking frequency and burst index is sufficient to determine precisely the vertical position of the STN. (C) 2002 Elsevier Science Ireland Ltd. All rights reserved.