Imaging of Motor Cortex Physiology in Parkinson's Disease

Abstract

There is abundant evidence that the pathophysiology of Parkinson's disease (PD) is not confined to the nigrostriatal dopaminergic pathway but propagates along the cortico‐basal ganglia‐thalamo‐cortical neural network. A critical node in this functional circuit impacted by PD is the primary motor cortex (M1), which plays a key role in generating neural impulses that regulate movements. The past several decades have lay witness to numerous in vivo neuroimaging techniques that provide a window into the function and structure of M1. A consistent observation from numerous studies is that during voluntary movement, but also at rest, the functional activity of M1 is altered in PD relative to healthy individuals, and it relates to many of the motor signs. Although this abnormal functional activity can be partially restored with acute dopaminergic medication, it continues to deteriorate with disease progression and may predate structural degeneration of M1. The current review discusses the evidence that M1 is fundamental to the pathophysiology of PD, as measured by neuroimaging techniques such as positron emission tomography, single‐photon emission computed tomography, electroencephalography, magnetoencephalography, and functional and structural MRI. Although novel treatments that target the cortex will not cure PD, they could significantly slow down and alter the progressive course of the disease and thus improve clinical care for this degenerative disease. © 2018 The Authors. Movement Disorders published by Wiley Periodicals, Inc. on behalf of International Parkinson and Movement Disorder Society

A systematic review of MEG‐based studies in Parkinson's disease: The motor system and beyond

“…So far, review articles tend to treat motor network‐focused studies (Burciu & Vaillancourt, ; Magrinelli et al, ) and whole‐brain studies (Cozac et al, ) separately. Although some efforts have been made to relate findings from motor networks to nonmotor symptoms (Oswal, Brown, & Litvak, ), it is unknown to what extent findings from motor networks and whole‐brain networks can be compared and if so, which similarities and discrepancies are present.…”

“…The source-level approach can resolve some of these ambiguities and enables interpretation of the functional results in an anatomical context (Baillet, Mosher, & Leahy, 2001;Brookes et al, 2007;Hillebrand, Barnes, Bosboom, Berendse, & Stam, 2012;Hillebrand, Singh, Holliday, Furlong, & Barnes, 2005;Schoffelen & Gross, 2009). So far, review articles tend to treat motor network-focused studies (Burciu & Vaillancourt, 2018;Magrinelli et al, 2016) and wholebrain studies separately. Although some efforts have been made to relate findings from motor networks to nonmotor symptoms (Oswal, Brown, & Litvak, 2013b), it is unknown to what extent findings from motor networks and whole-brain networks can be compared and if so, which similarities and discrepancies are present.…”

Levodopa Changes Functional Connectivity Patterns in Subregions of the Primary Motor Cortex in Patients With Parkinson’s Disease

“…One of the critical nodes in this motor circuit is the primary motor cortex (M1), which plays a key role in generating neural impulses that regulate movements ( Burciu and Vaillancourt, 2018 ; Hensel et al, 2019 ). The motor cortex (MC) includes M1 that not only participates in the classic BGMC circuit, which is used to explain the underlying mechanism of bradykinesia and rigidity, ( DeLong and Wichmann, 2015 ) but also participates in the MC-cerebellum-thalamus circuit, which could explain resting tremor ( Helmich et al, 2011 ; Dirkx et al, 2017 ).…”

Perturbation ofin vivoneural activity following α-Synuclein seeding in the olfactory bulb

“…These bands are thought to play unique roles in the olfaction (Kay et al, 2009). Adding to their significance, beta and gamma oscillations in key basal ganglia structures are perturbed in PD (Burciu and Vaillancourt, 2018;Little and Brown, 2014;McCarthy et al, 2011).…”