title: Neural substrates underlying stimulation-enhanced motor skill learning after stroke.
abstract: Motor skill learning is one of the key components of motor function recovery after stroke, especially recovery driven by neurorehabilitation. Transcranial direct current stimulation can enhance neurorehabilitation and motor skill learning in stroke patients. However, the neural mechanisms underlying the retention of stimulation-enhanced motor skill learning involving a paretic upper limb have not been resolved. These neural substrates were explored by means of functional magnetic resonance imaging. Nineteen chronic hemiparetic stroke patients participated in a double-blind, cross-over randomized, sham-controlled experiment with two series. Each series consisted of two sessions: (i) an intervention session during which dual transcranial direct current stimulation or sham was applied during motor skill learning with the paretic upper limb; and (ii) an imaging session 1 week later, during which the patients performed the learned motor skill. The motor skill learning task, called the 'circuit game', involves a speed/accuracy trade-off and consists of moving a pointer controlled by a computer mouse along a complex circuit as quickly and accurately as possible. Relative to the sham series, dual transcranial direct current stimulation applied bilaterally over the primary motor cortex during motor skill learning with the paretic upper limb resulted in (i) enhanced online motor skill learning; (ii) enhanced 1-week retention; and (iii) superior transfer of performance improvement to an untrained task. The 1-week retention's enhancement driven by the intervention was associated with a trend towards normalization of the brain activation pattern during performance of the learned motor skill relative to the sham series. A similar trend towards normalization relative to sham was observed during performance of a simple, untrained task without a speed/accuracy constraint, despite a lack of behavioural difference between the dual transcranial direct current stimulation and sham series. Finally, dual transcranial direct current stimulation applied during the first session enhanced continued learning with the paretic limb 1 week later, relative to the sham series. This lasting behavioural enhancement was associated with more efficient recruitment of the motor skill learning network, that is, focused activation on the motor-premotor areas in the damaged hemisphere, especially on the dorsal premotor cortex. Dual transcranial direct current stimulation applied during motor skill learning with a paretic upper limb resulted in prolonged shaping of brain activation, which supported behavioural enhancements in stroke patients.
authors.affiliation: 1 Université catholique de Louvain (UcL), CHU Dinant Godinne UcL Namur, Neurology Department, Avenue Dr G. Therasse, Yvoir 5530, Belgium 2 UcL, Institute of NeuroScience (IoNS), Brussels 1200, Belgium.
authors.forename: Stéphanie
authors.initials: S
authors.lastname: Lefebvre
authors.affiliation: 2 UcL, Institute of NeuroScience (IoNS), Brussels 1200, Belgium.
authors.forename: Laurence
authors.initials: L
authors.lastname: Dricot
authors.affiliation: 1 Université catholique de Louvain (UcL), CHU Dinant Godinne UcL Namur, Neurology Department, Avenue Dr G. Therasse, Yvoir 5530, Belgium 2 UcL, Institute of NeuroScience (IoNS), Brussels 1200, Belgium.
authors.forename: Patrice
authors.initials: P
authors.lastname: Laloux
authors.affiliation: 3 Imagilys, Brussels, Belgium 4 Warsaw University of Technology, Institute of Radioelectronics, Faculty of Electronics and Information Technology, Poland.
authors.forename: Wojciech
authors.initials: W
authors.lastname: Gradkowski
authors.affiliation: 5 Centre Hospitalier Chrétien (CHC), Site Saint-Joseph, Neurology Department, 4000 Liège, Belgium.
authors.forename: Philippe
authors.initials: P
authors.lastname: Desfontaines
authors.affiliation: 6 Clinique Saint-Pierre, Neurology Department, 1340 Ottignies, Belgium.
authors.forename: Frédéric
authors.initials: F
authors.lastname: Evrard
authors.affiliation: 7 UcL, Cliniques Universitaires Saint Luc, Unité neuro-vasculaire, Service de Neurologie, Avenue Hippocrate 10, 1200 Brussels, Belgium.
authors.forename: André
authors.initials: A
authors.lastname: Peeters
authors.affiliation: 8 UcL, CHU Dinant Godinne UcL Namur, Scientific Support Unit, Avenue Dr G. Therasse, Yvoir 5530, Belgium.
authors.forename: Jacques
authors.initials: J
authors.lastname: Jamart
authors.affiliation: 1 Université catholique de Louvain (UcL), CHU Dinant Godinne UcL Namur, Neurology Department, Avenue Dr G. Therasse, Yvoir 5530, Belgium 2 UcL, Institute of NeuroScience (IoNS), Brussels 1200, Belgium 9 UcL, Louvain Bionics, Louvain-la-Neuve 1348, Belgium yves.vandermeeren@uclouvain.be.
authors.forename: Yves
authors.initials: Y
authors.lastname: Vandermeeren
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D001931:Brain Mapping; D018592:Cross-Over Studies; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007858:Learning / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D009044:Motor Cortex / Q000098:blood supply / Q000473:pathology / Q000503:physiopathology; D019957:Motor Skills Disorders / Q000209:etiology / Q000534:rehabilitation*; D010100:Oxygen / Q000097:blood; D020521:Stroke / Q000150:complications / Q000473:pathology; D000071939:Stroke Rehabilitation; D050781:Transcranial Magnetic Stimulation / Q000379:methods*; D055815:Young Adult
chemical_list: D010100:Oxygen
keywords: fMRI; motor skill learning; neurorehabilitation; stroke; tDCS