PLASTICITY OF MOTOR ORGANIZATION IN CHILDREN AND ADULTS

WE explored the effects of maturational plasticity on motor activation s for the affected hand in patients with unilateral lesion involving t he rolandic cortex. Ten patients with early lesion (onset < 4 years), seven patients with late lesion (onset 10 years) and eight normal adul ts underwent [O-15]-water positron emission tomography (PET). Rolandic activations in the contralesional hemisphere were enhanced in both pa tient groups when compared to normal adults. Secondary motor and front oparietal nonmotor cortices were more activated in the early than in t he late lesion group, suggesting a greater potential for reorganizatio n during early development than later in life. Cerebellar activations mere similar in late lesion patients and normal adults, but significan tly weaker in early lesion patients.