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  • Interhemispheric Comparison of Globus Pallidus Interna and Cortical Local Field Potentials During Movement and Rest.

    Final Number:

    Nicholas Au Yong MD, PhD; Mahsa Malekmohammadi PhD candidate; Nader Pouratian MD PhD

    Study Design:
    Laboratory Investigation

    Subject Category:

    Meeting: Congress of Neurological Surgeons 2014 Annual Meeting

    Introduction: Neurophysiological studies following Deep Brain Stimulation (DBS) electrode placement for subjects with Parkinson’s Disease (PD) have largely focused on cortical and subcortical local field potentials (LFPs) within a single hemisphere. Such studies have demonstrated abnormal expression of beta “akinectic” (10–35 Hz) and gamma “prokinetic” (35–100 Hz) band oscillations within ipsilateral cortical and subcortical circuits. In this study, interhemispheric comparison of beta and gamma band LFP modulation between bilateral globus pallidus interna (GPi) and right motor/premotor cortical LFPs was carried out during left hand self-paced grasping and rest.

    Methods: Intraoperative LFPs were recorded from DBS electrodes bilaterally in the GPi and an electrocorticographic (ECog) strip overlying the right motor/premotor cortices in subjects diagnosed with PD or dystonia. Left hand activity was also captured via a sensor-embedded glove. Multi-taper power spectra and coherence estimates were analyzed between bilateral GPi and right cortical LFPs during periods of left hand grasping and rest.

    Results: In patients with PD, beta activity was most robust during periods of rest in bilateral GPi and right cortex. During grasping, beta oscillations were highly attenuated in the right GPi and cortex, but only moderately suppressed in the left GPi. The 230 Hz movement-related high gamma signal, previously reported by our group, demonstrated activity-related modulation bilaterally. In contrast to PD, in dystonia, cortical beta band oscillations were persistent throughout the entire recorded session and absent within bilateral GPi; possibly a neurophysiological signature of this disease.

    Conclusions: Activity related beta band suppression occurs bilaterally, although to a greater extent contralaterally. Moreover, despite beta suppression, pallidocortical coherence increases with activity. These contrasting features may provide additional insight into movement disorder pathophysiology and yield novel directions in DBS development.

    Patient Care: An understanding of the Interhemispheric similarities and differences in GPi and cortical LFP modulation may lead to improved diagnostic tools for movement disorder pathophysiology and yield novel directions in DBS development.

    Learning Objectives: By the conclusion of this session, participants should be able to: 1) Identify movement-related modulation of GPi and cortical LFP sub-bands and 2) Appreciate interhemispheric similarities and differences in LFP modulation.


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