Functional neuroimaging

After stroke, reorganization of surviving neural networks appears to be important for recovery of function. Noninvasive techniques such as functional magnetic resonance imaging allow some aspects of this reorganization to be studied in humans. In these experiments reorganization is apparent in cerebral networks in human stroke patients. For example, initial attempts to move a paretic limb following stroke are associated with widespread activity within the distributed motor system in both cerebral hemispheres, more so in patients with greater impairment. Disruption of activity in premotor areas using transcranial magnetic stimulation prior to movement can impair motor performance in stroke patients, suggesting that these new patterns of brain activity can support what recovered function there is. In other words, this reorganization is functionally relevant. This opens the way for functional brain imaging to become a clinically useful tool in rehabilitation. Understanding the dynamic process of systems-level reorganization will allow greater understanding of the mechanisms of recovery and potentially improve our ability to deliver effective restorative therapy.