title: Neural substrates underlying motor skill learning in chronic hemiparetic stroke patients.
abstract: Motor skill learning is critical in post-stroke motor recovery, but little is known about its underlying neural substrates. Recently, using a new visuomotor skill learning paradigm involving a speed/accuracy trade-off in healthy individuals we identified three subpopulations based on their behavioral trajectories: fitters (in whom improvement in speed or accuracy coincided with deterioration in the other parameter), shifters (in whom speed and/or accuracy improved without degradation of the other parameter), and non-learners. We aimed to identify the neural substrates underlying the first stages of motor skill learning in chronic hemiparetic stroke patients and to determine whether specific neural substrates were recruited in shifters versus fitters. During functional magnetic resonance imaging (fMRI), 23 patients learned the visuomotor skill with their paretic upper limb. In the whole-group analysis, correlation between activation and motor skill learning was restricted to the dorsal prefrontal cortex of the damaged hemisphere (DLPFCdamh: r = -0.82) and the dorsal premotor cortex (PMddamh: r = 0.70); the correlations was much lesser (-0.16 < r > 0.25) in the other regions of interest. In a subgroup analysis, significant activation was restricted to bilateral posterior parietal cortices of the fitters and did not correlate with motor skill learning. Conversely, in shifters significant activation occurred in the primary sensorimotor cortexdamh and supplementary motor areadamh and in bilateral PMd where activation changes correlated significantly with motor skill learning (r = 0.91). Finally, resting-state activity acquired before learning showed a higher functional connectivity in the salience network of shifters compared with fitters (qFDR < 0.05). These data suggest a neuroplastic compensatory reorganization of brain activity underlying the first stages of motor skill learning with the paretic upper limb in chronic hemiparetic stroke patients, with a key role of bilateral PMd.
authors.affiliation: Institute of Neuroscience, Université Catholique de Louvain Brussels, Belgium ; Neurology Department, CHU Dinant-Godinne UCL Namur, Université Catholique de Louvain Yvoir, Belgium.
authors.forename: Stéphanie
authors.initials: S
authors.lastname: Lefebvre
authors.affiliation: Institute of Neuroscience, Université Catholique de Louvain Brussels, Belgium.
authors.forename: Laurence
authors.initials: L
authors.lastname: Dricot
authors.affiliation: Institute of Neuroscience, Université Catholique de Louvain Brussels, Belgium ; Neurology Department, CHU Dinant-Godinne UCL Namur, Université Catholique de Louvain Yvoir, Belgium.
authors.forename: Patrice
authors.initials: P
authors.lastname: Laloux
authors.affiliation: Imagilys Brussels, Belgium ; Faculty of Electronics and Information Technology, Institute of Radioelectronics, Warsaw University of Technology Warsaw, Poland.
authors.forename: Wojciech
authors.initials: W
authors.lastname: Gradkowski
authors.affiliation: Neurology Department, Site Saint-Joseph, CHC Liège, Belgium.
authors.forename: Philippe
authors.initials: P
authors.lastname: Desfontaines
authors.affiliation: Neurology Department, Clinique Saint-Pierre Ottignies, Belgium.
authors.forename: Frédéric
authors.initials: F
authors.lastname: Evrard
authors.affiliation: Service de Neurologie, Unité Neuro-Vasculaire, Cliniques Universitaires Saint Luc UCL, Université Catholique de Louvain Brussels, Belgium.
authors.forename: André
authors.initials: A
authors.lastname: Peeters
authors.affiliation: Scientific Support Unit, CHU Dinant-Godinne UCL Namur, Université Catholique de Louvain Yvoir, Belgium.
authors.forename: Jacques
authors.initials: J
authors.lastname: Jamart
authors.affiliation: Institute of Neuroscience, Université Catholique de Louvain Brussels, Belgium ; Neurology Department, CHU Dinant-Godinne UCL Namur, Université Catholique de Louvain Yvoir, Belgium ; Louvain Bionics, Université Catholique de Louvain Louvain-la-Neuve, Belgium.
authors.forename: Yves
authors.initials: Y
authors.lastname: Vandermeeren
keywords: fMRI; functional connectivity; motor skill learning; neurorehabilitation; premotor cortex; resting-state fMRI; stroke