Unimanual Versus Bimanual Motor Skill Learning in Acute and Chronic Stroke

To test the capacity of healthy individuals, chronic and acute stroke patients to learn and retain a complex unimanual or bimanual motor skill, trained on the neurorehabiliation robot REAplan® et the Dextrain® device. The goals are (1) to compare head-to-head bimanual versus unimanual motor learning (in the proximal and distal upper limb, UL) during the acute - early subactue stage of stroke with robotics and (2) to identify the neural substrates associated with (and deficits in) unimanual versus bimanual motor control (proximal and distal) after stroke by means of multimodal brain imaging.

STROKE PATIENTS Inclusion Criteria: * acute stroke (between day 2 and day 21 post-stroke) or chronic stroke (\>6 mois) * aged 40-90 years * with a single demonstrated stroke (ischemic or hemorrhagic) lesion on brain imaging Exclusion Criteria: * \[for acute paitents\] "classical" contre-indication to MRI (non-MR-compatible pacemaker, pregnancy, non-MR-compatible implanted devices, claustrophobia, etc ...) * difficulty in understanding or executing commands * drug/alcohol abuse * severe aphasia/cognitive deficits interfering with study * inability to complete the tasks (i.e. full paralysis of the arm) * multiple stroke/dementia/psychiatric condition HEALTHY INDIVIDUALS Inclusion Criteria: * 40-90 years Exclusion Criteria: * "classical" contre-indication to MRI (non-MR-compatible pacemaker, pregnancy, non-MR-compatible implanted devices, claustrophobia, etc ...) * medical history with a previous stroke/relevant neurological deficit * drug/alcohol abuse * psychiatric condition/dementia * having already used the robotic devices