Prominent 5–18 Hz oscillations in the pallidal-thalamic circuit in secondary dystonia

Abstract

Previous studies in primary dystonia suggested that abnormal oscillations of 5–18 Hz in the bilateral internal globus pallidus (GPi) may be a specific feature of dystonia.1–3 Moreover, voluntary movements were associated with bilateral desynchronization of β (<30 Hz) and contralateral synchronization of γ (∼70 Hz) frequencies in the GPi.2–4 We recorded local field potentials (LFPs) from the GPi and motor thalamus in a patient with severe hemidystonia to test the following hypotheses. First, the 5–18 Hz synchronization is present in the basal ganglia (BG)–thalamic circuit in patients with secondary dystonia. Second, the bilaterally coherent 5–18 Hz activity may be transmitted between the hemispheres through the motor thalamus. Finally, if the 5–18 Hz rhythm is related to dystonia, attempted movements of dystonic muscles would result in less attenuation of this 5–18 Hz oscillation compared to normal movements.