IMPAIRMENT OF DENTATO-THALAMO-CORTICAL PATHWAY IN AUTISTIC MEN - LANGUAGE ACTIVATION DATA FROM POSITRON-EMISSION-TOMOGRAPHY

Recent evidence suggests disturbances of serotonin synthesis affecting the dentato-thalamo-cortical pathway in autistic boys. We studied pos sible effects of such disturbances on brain activations for language i n autistic adults. Four autistic and five normal men were studied whil e listening to, repeating, and generating sentences, using [O-15]-wate r positron emission tomography (PET), Activation in the right dentate nucleus and in the left frontal area 46 was reduced during verbal audi tory and expressive language and enhanced during motor speech function s in the autism as compared to the control group. The thalamus showed group differences concordant with area 46 for expressive language. The results may indicate atypical functional specialization of the dentat o-thalamo-cortical pathway and are compatible with a model of region-s pecific biochemical disturbances in the developing autistic brain. (C) 1998 Elsevier Science Ireland Ltd.