To describe the single unit activity (SUA) and local field potential (LFP) characteristics of a patient with idiopathic Parkinson’s disease (PD) during a dyskinesia episode.

SUA and LFPs in the unmedicated state of patients with PD undergoing deep brain stimulation (DBS) procedures are well characterized. Although LFP spectral dynamics are known to change in the ON state, less is understood about how this corresponds to changes in SUA, or how either LFP or SUA interacts during dyskinesia episodes.

Of 14 neurons isolated, almost all showed tonic firing (fast and some irregular) with a mean firing rate of 63.0 ± 29.8Hz, (higher than previously reported in the unmedicated state). No neurons showed bursting activity as quantified with ISI histograms showing single peaks.  LFP activity was characterized by weak beta (22Hz) oscillations, a sharp gamma (80Hz) peak, and strong high frequency oscillations (HFOs) around 300Hz. No coupling between beta and HFO was seen, as previously reported in medicated patients. The SUA was not phase coupled to beta LFP (unlike previously described unmedicated PD patients). Interestingly, sharp gamma activity commenced 10mm above the STN, indicating broader network synchronization. Contralateral dyskinesia improved during stimulation testing of the DBS lead. 

This case demonstrates unique SUA and LFP findings during a dyskinesia episode in PD, highlighting the need for a more complete understanding of local and network dynamics in PD for use in closed loop DBS systems.