Pallidal deep brain stimulation modulates excessive cortical high β phase amplitude coupling in Parkinson disease

Mahsa Malekmohammadi; Nicholas AuYong; Joni Ricks-Oddie; Yvette Bordelon; Nader Pouratian

doi:10.1016/j.brs.2018.01.028

Pallidal deep brain stimulation modulates excessive cortical high β phase amplitude coupling in Parkinson disease

Brain Stimul. 2018 May-Jun;11(3):607-617. doi: 10.1016/j.brs.2018.01.028. Epub 2018 Jan 31.

Authors

Mahsa Malekmohammadi¹, Nicholas AuYong², Joni Ricks-Oddie³, Yvette Bordelon⁴, Nader Pouratian⁵

Affiliations

¹ Department of Neurosurgery, University of California, Los Angeles, CA, USA. Electronic address: mmalekmohammadi@mednet.ucla.edu.
² Department of Neurosurgery, University of California, Los Angeles, CA, USA.
³ Institute for Digital Research and Education (IDRE), University of California, Los Angeles, CA, USA.
⁴ Department of Neurology, University of California, Los Angeles, CA, USA.
⁵ Department of Neurosurgery, University of California, Los Angeles, CA, USA; Department of Bioengineering, University of California, Los Angeles, CA, USA; Neuroscience Interdepartmental Program, University of California, Los Angeles, CA, USA; Brain Research Institute, University of California, Los Angeles, CA, USA.

Abstract

Objective: Deep brain stimulation (DBS) of the subthalamic nucleus (STN) and globus pallidus internus (GPi) are equally efficacious in the management of Parkinson disease (PD). Studies of STN-DBS have revealed a therapeutic reduction in excessive cortical β-γ phase-amplitude coupling (PAC). It is unclear whether this is specific to STN-DBS and potentially mediated by modulation of the hyperdirect pathway or if it is a generalizable mechanism seen with DBS of other targets. Moreover, it remains unclear how cortical signals are differentially modulated by movement versus therapy. To clarify, the effects of GPi-DBS and movement on cortical β power and β-γ PAC were examined.

Methods: Right sensorimotor electrocorticographic signals were recorded in 10 PD patients undergoing GPi-DBS implantation surgery. We evaluated cortical β power and β-γ PAC during blocks of rest and contralateral hand movement (finger tapping) with GPi-DBS off and on.

Results: Movement suppressed cortical low β power (P = 0.008) and high β-γ PAC (P = 0.028). Linear mixed effect modeling (LMEM) showed that power in low and high β bands are differentially modulated by movement (P = 0.022). GPi-DBS also results in a significant suppression of high β-γ PAC but without power modulation in either β sub-band (P = 0.008). Cortical high β-γ PAC is significantly correlated with severity of bradykinesia (Rho = 0.59, P = 0.045) and changes proportionally with therapeutic improvement (Rho = 0.61, P = 0.04).

Conclusions: Similar to STN-DBS, GPi-DBS reduces motor cortical β-γ PAC, like that also reported with dopaminergic mediations, suggesting it is a generalizable symptom biomarker in PD, independent of therapeutic target or proximity to the hyperdirect pathway.

Keywords: Deep brain stimulation; Globus pallidus internus; Motor cortex; Parkinson disease; Phase amplitude coupling.

Publication types

Clinical Trial
Research Support, N.I.H., Extramural
Research Support, Non-U.S. Gov't

MeSH terms

Aged
Beta Rhythm / physiology*
Cerebral Cortex / physiology*
Deep Brain Stimulation*
Electrocorticography
Female
Gamma Rhythm / physiology*
Globus Pallidus / physiology*
Humans
Male
Middle Aged
Models, Neurological
Movement / physiology
Parkinson Disease / therapy*

Abstract

Publication types

MeSH terms

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