Oscillatory activity in the human globus pallidus during walking
10 slide(s) – English – 2011-09-10
Introduction: Nowadays, globus pallidum internum (GPi) represents the most therapeutic target for deep brain stimulation (DBS) in dystonia. Pallidal recordings of local field potentials (LFPs) in patients with dystonia have demonstrated 3-12 Hz pathophysiological oscillatory activities. Gait disturbance, one of the axial symptoms, may also be caused by basal ganglia disease and can be seen as a symptom of dystonia. DBS electrodes also give us an opportunity to investigate basal ganglia involvement in gait cycle phase during steady-speed human walking.
Methods: To this end, we recorded LFPs from deep brain stimulation electrodes implanted into the GPi of dystonic patients during rest (sitting and standing) and walk on a treadmill machine. All subjects walked bare-foot with preferred velocity.
Results: There was not any difference in the power of frequency bands during sitting and standing conditions. LFP power in the theta (4-8 Hz), alpha (8-12 Hz) and gamma (60-90 Hz) frequency bands was higher during walking as compared to resting condition (sitting). Oscillatory activities were observed higher in lower contact as compared to upper contact of macroelectrode. Synchronized alpha frequency modulation was observed in the beginning of stance and swing phase of a gait cycle.
Conclusions: In the present study, we were able to show that prominent activity in the theta, alpha and gamma frequency bands significantly contribute to the involvement of the human globus pallidus during walking. The dynamic organization of frequency band activities in the human GPi therefore provide information of pathophysiological circuit of basal ganglia involved in movement disorders during walking.