PURPOSE OF REVIEW: The aim of this article is to review current advances in functional magnetic resonance imaging and positron emission tomography of the motor system in parkinsonism and dystonia. RECENT FINDINGS: In Parkinson's disease, recent functional magnetic resonance imaging studies have shown that the pattern of regional activity changes in the motor system are strongly modulated by the amount of attention patients pay to task performance. In focal hand dystonia, functional magnetic resonance imaging has disclosed several functional alterations in the basal ganglia in addition to the well-known cortical abnormalities. Neuroimaging has also been successfully used to assess the impact of pharmacological or surgical interventions. In patients with monogenetically inherited parkinsonism or dystonia, positron emission tomography and functional magnetic resonance imaging have opened up exciting possibilities to link molecular biology with functional changes at a systems level. Neuroimaging of genetically defined at-risk populations has shown great potential to study motor reorganization at the preclinical stage and to identify adaptive mechanisms that prevent or delay clinical manifestation. SUMMARY: Functional neuroimaging plays a key role in understanding the pathophysiology of parkinsonism and dystonia. A future challenge will be to clarify how these disorders impair the functional integration within the motor system and how these changes in connectivity are influenced by therapeutic interventions.
