Cortical networks of parkinsonian gait: a metabolic and functional connectivity study

Abstract

AbstractObjectiveLocomotion is an automated voluntary movement sustained by coordinated neural synchronization across a distributed brain network. The cerebral cortex is central for adapting the locomotion pattern to the environment and alterations of cortical network dynamics can lead to gait impairments. Gait problems are a common symptom with a still unclear pathophysiology and represent an unmet therapeutical need in Parkinson’s disease. Little is known about the cortical network dynamics of locomotor control in these patients.MethodsWe studied the cortical basis of parkinsonian gait by combining metabolic brain imaging with high-density EEG recordings and kinematic measurements performed at rest and during unperturbed overground walking.ResultsWe found significant changes in functional connectivity between frontal, sensorimotor and visuomotor cortical areas during walking as compared to resting. Specifically, hypokinetic gait was associated with poor information flow from the supplementary motor area (SMA) to precuneus and from calcarine to lingual gyrus as well as high information flow from calcarine to cuneus.InterpretationOur findings support a role for visuomotor integration processes in PD-related hypokinetic gait and suggest that reinforcing visual information may act as a compensatory strategy to allow SMA-related feedforward locomotor control in PD.