Neuronal activity in globus pallidus interna can be synchronized to local field potential activity over 3–12 Hz in patients with dystonia

Pallidal recordings of local field potentials (LFPs) in patients with dystonia have demonstrated semi-oscillatory activity over 3–12 Hz. Although this activity has been hypothesized to contribute to dystonia, it is unclear to what extent these LFP oscillations arise in the globus pallidus interna (GPi) and are synchronous with local neuronal discharge. We therefore recorded LFPs and neuronal activity from microelectrodes inserted into the pallidum on nine sides in six awake patients with primary dystonia during functional neurosurgery. Mean normalized LFP power over 3–12 Hz was higher in GPi than globus pallidus externa. Spike triggered averages were computed, and 11 exhibited significant features in the 3–12 Hz band, indicating that the discharges of local neurons were locked to 3–12 Hz oscillations in the LFP. All but two of these STAs were in GPi. We conclude that pallidal oscillations at 3–12 Hz are maximal in GPi, the surgical target, in patients with dystonia and that they can be synchronized to activity in local neurons. This lends support to a pathophysiological relationship between LFP activity at 3–12 Hz and dystonia.