Processing of Motor Performance Related Reward After Stroke

Performance dependent reward activates the striatum, a key region of the reward system. However, stroke patients were identified to show reduced brain activations to rewarding feedback in cognitive tasks when compared to healthy age-matched controls. This was reflected in impaired reinforcement learning. Whether their response to reward derived from preceding motor performance is also reduced, is, however, still unknown. Using functional magnetic resonance imaging, striatal activity linked to performance dependent monetary reward was measured during the training of a repetitive arc-tracking task. Pilot results of nine stroke patients and nine age-matched healthy individuals point towards a tendency for reduced responsiveness of ventral parts of the striatum in stroke patients, while the dorsal striatum, although to a smaller extent, shows an opposite trend. This is of particular interest as ventral striatal activation was found to be the key factor for successful overnight consolidation in an earlier study using a similar task.