[en] To determine involvements of the brain stem and/or cerebellum in autism, we compared midsagittal magnetic resonance images of the brains of high functioning autistic children with those of normal controls. We found that the midbrain and medulla oblongata were significantly smaller in these autistic children than in the control children. The pons area did not differ between the two groups, nor was there any difference in the cerebellar vermis area. The ratio of the brain stem and cerebellum to the posterior fossa area did not differ significantly between the high functioning autistic and the control children. The development of the cerebellar vermis area was delayed in autistic children as compared with that in the control children. Thus, it was suggested that significant anatomical changes in the midbrain and medulla oblongata existed in the autistic children. (author)