Besides recent genetic findings supporting the role of neuronal cell-adhesion molecules in the pathogenesis of autism, an increasing number of functional neuroimaging studies have suggested the presence of cortical underconnectivity in subjects with ASDs44,45. Furthermore, neuroanatomy studies have implicated abnormal brain development of the frontal lobes in autism46,47. The genetic findings, when coupled with anatomical and functional imaging studies, convergently indicate that ASDs may result from structural and functional disconnection of brain regions that are involved in higher-order associations48-50, suggesting that ASDs may represent a neuronal disconnection syndrome.
