Cortically evoked potentials in the human subthalamic nucleus

• Published in: Neuroscience letters 2013-02, Vol.539, p.27-31
• Main Authors: Zwartjes, Daphne G.M., Janssen, Marcus L.F., Heida, Tjitske, Van Kranen-Mastenbroek, Vivianne, Bour, Lo J., Temel, Yasin, Visser-Vandewalle, Veerle, Veltink, Peter H.
• Format: Article
• Language: English
• Subjects: Aged; Cerebral Cortex - physiopathology; Cortex (motor); Deep Brain Stimulation; Electric Stimulation; Evoked Potentials; Humans; Local field potential; Middle Aged; Motor Cortex - physiopathology; Motor cortex stimulation; Neurons - physiology; Parkinson Disease - physiopathology; Parkinson Disease - therapy; Parkinson's disease; Subthalamic nucleus; Subthalamic Nucleus - physiopathology
• ISSN: 0304-3940; 1872-7972
• DOI: 10.1016/j.neulet.2013.01.036

► We hypothesize that DBS in the STN motor area gives the optimal effect for PD. ► We perform motor cortex stimulation and measure the evoked potentials in the STN. ► We hypothesize that the cortically evoked potentials can identify the STN motor area. ► Cortically evoked potentials follow a specific spatial and temporal pattern in the STN. ► The evoked subthalamic potentials are partly related to the unit responses. Deep brain stimulation (DBS) of the subthalamic nucleus (STN) alleviates motor symptoms in Parkinson's disease (PD) patients. However, in a substantial number of patients the beneficial effects of STN DBS are overshadowed by psychiatric side effects. We hypothesize that stimulation of the STN motor area will provide the optimal effect on the motor symptoms without inducing these side effects, and expect that motor cortex stimulation (MCS) evokes a spatially specific response within the STN, which identifies the STN motor area. We previously showed that MCS evokes responses in the unit activity specifically within certain areas of the STN. Unit activity is generally considered a measure of the output activity. To gain more insight into the neuronal input into the STN, we describe the results of cortically evoked subthalamic local field potentials (LFPs). We show that the cortically evoked LFPs follow a certain temporal and spatial pattern. The significant peaks of the evoked LFPs coincide with the timing of some of the inhibitions and excitations present in the unit responses. The spatial resolution of responses measured in the LFP to MCS is not high enough to identify the STN motor region. However, we believe that optimizing targeting techniques and the development of novel DBS electrodes will improve STN DBS therapy for PD patients.