[Rehabilitation after stroke. Imaging techniques show how the cortical reorganization is affected by training]

It is widely accepted that reorganisation of the brain occurs after a focal brain lesion such as stroke. Neuroimaging methods are used to study such reorganisation in vivo. Improvements in arm and hand motor function during recovery post-stroke have been related to reorganisation in primary and secondary sensorimotor areas by indirect measure of synaptic activity with functional MRI. Reorganisation occurs in both the affected and the unaffected hemispheres. Preliminary training studies post-stroke have shown correlations between improvements in motor function and brain activity changes. Recent research findings are reviewed herein. Further understanding of the neurobiological mechanisms of post-stroke recovery will lead to development of optimal treatment strategies during rehabilitation of stroke survivors.