Brain representation of active and passive hand movements in children.

Several functional neuroimaging studies have been performed exploring the sensorimotor function in children with neurologic disorders. However, little is known about normal activation patterns of the sensorimotor system at a young age. We explored brain representation of active and passive hand movements in school-age children and young adults. Nine healthy children (7-15 y) and six adults were studied. Functional magnetic resonance imaging (fMRI) data were acquired on a 1.5-T scanner in block designs. Active movement consisted of repetitive opening and closing of the hand; passive movement consisted of the same movement performed by the examiner. Both hands were assessed separately. The pattern of brain activation (contralateral primary sensorimotor cortex (SMC), ipsilateral cerebellum, supplementary motor area (SMA), and lateral premotor cortex (PMC) was generally more widespread in the adult group, suggesting a developmental course in the organization of both motor and sensory cortex. Surprisingly, no difference was generally detected when contrasting active versus passive tasks. Our results suggest that active and passive hand movements can be used for the exploration of the sensorimotor system in children. Passive and active tasks confirmed to be tightly coupled, thus supporting the idea of the former as a helpful performance-independent paradigm in the study of brain reorganization and presurgical assessment.