Atypical patterns of cerebral motor activation in autism: A functional magnetic resonance study

Background: Early neurodevelopmental pathogenesis in autism potentially aff ects emerging functional maps, but little imaging evidence is available. Methods: We studied eight male autistic and eight marched normal subjects, using functional magnetic resonance imaging during visually paced finger mo vement, compared to a control condition (visual stimulation in the absence of motor response). Results: Groupwise analyses showed activation in contralateral perirolandic cortex, basal ganglia, and thalamus, bilateral supplementary motor area, a nd ipsilateral cerebellum for both groups. However, activations were less p ronounced in the autism group. Direct group com parisons demonstrated great er activation in perirolandic and supplementary motor areas in the control group and greater activation (or reduced deactivation) in posterior and pre frontal cortices in the autism group, Intraindividual analyses further show ed that strongest activations were consistently located along the contralat eral central sulcus in control subjects bur occurred in locations differing from individual to individual in the autism group. Conclusions: Our findings, though based on a rather small sample, suggest a bnormal individual variability of functional maps and less distinct regiona l activation/deactivation patterns in autism. The observations may relate t o known motor impairments in autism and are compatible with the general hyp othesis of disturbances of functional differentiation in the autistic cereb rum. (C) 2001 Society of Biological Psychiatry.