Deep brain stimulation in Parkinson's disease can mimic the 300 Hz subthalamic rhythm.

We read with much interest the paper by Meissner et al . (2005) recently published in Brain . The authors provided neurophysiological evidence that in MPTP-treated monkeys high-frequency (130 Hz) deep brain stimulation (DBS) of the subthalamic nucleus (STN) dramatically resets the firing activity of individual STN neurons, so that the firing probability is virtually zero immediately after each stimulus pulse and rapidly recovers to baseline levels before the appearance of the subsequent stimulus (significant firing rate increase within 4 ms). This DBS-induced resetting determines an overall decrease in the firing rate of STN neurons and disrupts abnormal oscillations at relatively low frequencies (<30 Hz). The authors ‘focused on the 4–30 Hz range, since MPTP treatment induces almost exclusively significant oscillations in that frequency band’. They argue that the reduction of these oscillations could be at least partially responsible for the clinical benefits induced by DBS of the STN. Despite possible differences in the main frequencies of oscillations between human and non-human primates, the above interpretation is consistent with the dopamine-dependent reduction of beta oscillations observed in local field potentials (LFPs) recorded from the STN of patients with Parkinson's disease, as properly discussed by the authors, which were described in detail also by our group (Priori et al ., 2004; Foffani et al ., 2005, 2006; Marceglia et al ., 2006). LFP data from the STN of parkinsonian patients also suggest a more provocative interpretation of the results reported by Meissner et al . (2005). In a previous paper published in this journal, we found a fast rhythm operating in the human STN at surprisingly high frequencies, around 300 Hz (Foffani et al ., 2003 …