Absence of magnetic resonance imaging evidence of pontine abnormality in infantile autism
M. Hsu, R. Yeung-Courchesne, E. Courchesne and G. A. Press
Department of Neurosciences, School of Medicine, University of California, San Diego, La Jolla.
In vivo studies involving magnetic resonance imaging and studies of
neuropathologic specimens have shown that autism is most consistently
associated with developmental hypoplasia of the neocerebellum. We
investigated whether the cerebellar hypoplasia was accompanied by gross
structural abnormalities in the major input (cerebrocerebellar) and output
(cerebrorubral) pathways to the cerebellum by measuring the area of the
ventral pons (including the pontine nuclei and the transverse fibers) and
the midbrain on midsagittal magnetic resonance images in 34 autistic and 44
subjects. The area of the entire pons and several regions of interest
within the midbrain (including the superior and inferior colliculi) were
also determined with midsagittal magnetic resonance images. We found no
significant difference between measurements of the pons and midbrain in
autistic and control subjects. Our data show no evidence of gross anatomic
abnormalities in the input and output pathways to the cerebellum in autism,
a finding that is consistent with previous studies of neuropathologic
specimens; rather, the reduced size of the neocerebellum in autism appears
to be the result of maldevelopment within the cerebellum itself.
