Experimental neurology
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Experimental neurology · Jul 2013
ReviewAdaptive deep brain stimulation (aDBS) controlled by local field potential oscillations.
Despite their proven efficacy in treating neurological disorders, especially Parkinson's disease, deep brain stimulation (DBS) systems could be further optimized to maximize treatment benefits. In particular, because current open-loop DBS strategies based on fixed stimulation settings leave the typical parkinsonian motor fluctuations and rapid symptom variations partly uncontrolled, research has for several years focused on developing novel "closed-loop" or "adaptive" DBS (aDBS) systems. aDBS consists of a simple closed-loop model designed to measure and analyze a control variable reflecting the patient's clinical condition to elaborate new stimulation settings and send them to an "intelligent" implanted stimulator. The major problem in developing an aDBS system is choosing the ideal control variable for feedback. Here we review current evidence on the advantages of neurosignal-controlled aDBS that uses local field potentials (LFPs) as a control variable, and describe the technology already available to create new aDBS systems, and the potential benefits of aDBS for patients with Parkinson's disease.
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Experimental neurology · Jul 2013
Spatial extent of β oscillatory activity in and between the subthalamic nucleus and substantia nigra pars reticulata of Parkinson's disease patients.
Parkinson's disease (PD) is accompanied by a significant amount of β-band (11 Hz-30 Hz) neuronal and local field potential (LFP) oscillatory activity in the subthalamic nucleus (STN). Previous studies have shown significant coherence between neuronal firing and LFPs at β frequencies at sites separated by ~1 mm and that the magnitude of β oscillatory LFP activity and coherence are greatly reduced following levodopa administration. However, these data have been collected from large DBS contact electrodes or pairs of microelectrodes in proximity to each other and so it is not clear whether all regions of STN are synchronized. ⋯ We confirmed previous reports of a progressive attenuation in β power as electrodes were driven from dorsal to ventral STN and into SNr. Furthermore, we found significant β-LFP coherence across the dorsoventral extent of STN. Detailed analysis suggested that at least some of the ventral STN and SNr beta activity was locally generated rather than arising from volume conduction from dorsal STN and thus suggests that β oscillations synchronize both the input and output nuclei of the basal ganglia.