Dopaminergic modulation of motor network dynamics in Parkinson's disease.
Bottom Line: Preserved performance during external cueing was associated with enhanced connectivity between prefrontal cortex and lateral premotor cortex OFF medication, compatible with a context-dependent compensatory role of the lateral premotor loop in the hypodopaminergic state.Dopaminergic medication significantly improved finger tapping speed in patients, which correlated with a drug-induced coupling increase of prefrontal cortex with the supplementary motor area, i.e. the mesial premotor loop.In contrast, medication did not improve internal motor control deficits concurrent to missing effects at the connectivity level.
Affiliation: 1 Department of Neurology, Cologne University Hospital, Kerpener Str. 62, 50937 Cologne, Germany 2 Max Planck Institute for Neurological Research, Gleueler Str. 50, 50931 Cologne, Germany.Show MeSH
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Mentions: We used a computerized motor task to probe basic motor functions as well as executive functions engaged in movement preparation and selection (Fig. 1). In all conditions, subjects responded via button presses on a MRI compatible response device using the right or left index finger. Visual stimuli were generated using the ‘Presentation’ software package (Version 10.3, Neurobehavioral Systems Inc.). The task comprised four conditions [slightly modified version of the task used in Michely et al. (2012)]. Each condition was presented in blocks of 20 s duration separated by resting baselines of 16 s during which subjects watched a blank screen. Each block was introduced by a one-word instruction presented for 2.5 s, informing the subject about which of the four conditions followed next.
Affiliation: 1 Department of Neurology, Cologne University Hospital, Kerpener Str. 62, 50937 Cologne, Germany 2 Max Planck Institute for Neurological Research, Gleueler Str. 50, 50931 Cologne, Germany.