Neuroimaging in the developmental disorders: The state of the science

The developmental disorders of childhood-autistic, developmental language, reading (dyslexia), and attention deficit-hyperactivity disorders-manifest with deficits in the traditional behavioral domains of cognition, language, visual-spatial function, attention, and socialization. However, none of th ese disorders has been associated with characteristic discrete focal lesion s or recognized encephaloclastic processes. Developmental cognitive neurosc ientists must therefore begin with the spectrum of sometimes divergent beha viors occurring within these disorders and work backward in an attempt to i dentify the responsible anomalous neural systems. Since the advent of "brai n imaging" two decades ago, much effort has focused on identifying brain-be havior correlates in these disorders. The results of these neuropathologic, structural, and functional neuroimaging studies are presented and the reas ons for the often divergent findings are discussed. As we approach the end of the Decade of the Brain, current neuroimaging techniques give us the tec hnology for the first time to apply a fundamental cognitive approach to bra in-behavior relationships in the developmental disorders, to eliminate the conglomeration of "apples and camels" phenomenon. Researchers are working t ogether to create comparable protocols and to adhere to methods that can be replicated across sites. The future prospects for a greater understanding of the developmental disorders are now much brighter with neuroimaging tech nology.