Clinical Implications of Local Field Potentials for Understanding and Treating Movement Disorders

Abstract

Background: Deep brain stimulation (DBS) for the treatment of movement disorders has provided researchers with an opportunity to record electrical oscillatory activity from electrodes implanted in deep brain structures. Extracellular activity recorded from a population of neurons, termed local field potentials (LFPs), has shed light on the pathophysiology of movement disorders and holds the potential to lead to refinement in existing treatments. Objective: This paper reviews the clinical significance of LFPs recorded from macroelectrodes implanted in basal ganglia and thalamic targets for the treatment of Parkinson's disease, essential tremor and dystonia. Methods: Neural population dynamics and subthreshold events, which are undetectable by single-unit recordings, can be examined with frequency band analysis of LFPs (frequency range: 1-250 Hz). Results: Of clinical relevance, reliable correlations between motor symptoms and components of the LFP power spectrum suggest that LFPs may serve as a biomarker for movement disorders. In particular, Parkinson's rigidity has been shown to correlate with the power of beta oscillations (13-30 Hz), and essential tremor coheres with oscillations of 8-27 Hz. Furthermore, evidence indicates that the optimal contacts for DBS programming can be predicted from the anatomic location of beta and gamma bands (48-200 Hz). Conclusion: LFP analysis has implications for improved electrode targeting and the development of a real-time, individualized, ‘closed-loop' stimulation system.

Intraoperative macroelectrode local field potential recordings in Essential Tremor

“…In order to explore the frequency content of the LFP data at each depth, depth-frequency analysis was generated similar to the well-published time-frequency analysis approach [5]. Despite the prior artifact removal steps, LFP signal corruption was still observable, and attributable by factors such as tremor and/or environmental factors in the operating room.…”

REM sleep behaviour disorder: prodromal and mechanistic insights for Parkinson's disease

“…Activity is measured using electrophysiological signals, including single-unit potential and local field potential (LFP). LFPs are oscillations thought to represent the aggregate discharges from neurons within the immediate vicinity of recording sites 28 29. LFP can be recorded through the same macroelectrode contacts used to deliver stimulation via DBS.…”

Motor behaviors in the sheep evoked by electrical stimulation of the subthalamic nucleus

“…The traditional view that STN DBS side effects most commonly result from inadvertent stimulation of capsular fibers [55][56][57][58][59] is supported by the location of the IC immediately lateral to STN in both human and nonhuman primate brains [60,61]. However, capsular fibers in the sheep brain terminate ~10 mm lateral to the STN [41]; (see Figure 1A), suggesting instead that the stimulation-evoked Although the mechanisms of therapeutic DBS are not well understood, intraoperative macrorecordings from movement disorder patients support the hypothesis that the treatment works by suppressing exaggerated low-frequency oscillations detected within the basal ganglia [65]. PD motor symptom improvement mediated by DBS or medication therapy coincides with a decrease in the abnormal beta band (13-30 Hz) oscillations [66][67][68][69][70], while excessive beta activity can be induced in patients through administration of dopamine antagonists [71].…”