This panel will present tombstones of migratory abnormalities in the brains of ASD individuals. First, neuroimaging techniques have found a blurring of the gray/white matter junction. The blurring is the result of a migratory defect where cells going to the cerebral cortex get stuck in the subplate region. Second, we will explore the neuropathology of corpus callosum abnormalities in order to indicate that axonal guidance defects are closely related to abnormalities of neuronal migration, e.g., heterotopias, an increase in subpial neurons, and cortical malformations. These neuropathological findings have been reported in a significant number of ASD individuals. Third, diffusion tensor imaging (DTI) of the cerebral cortex of ASD individuals have shown abnormalities in diffusivity that correspond to minicolumnar disorganization. Lastly, during corticogenesis radially migrating neuroblasts interact with tangentially migrating neuroblasts to form physiological dyads. In ASD an apparent heterochonic migration of radial cells results in anomalous cellular dyads and a relative reduction of interneurons. The findings presented in this panel indicate that ASD is a neurodevelopmental disorder. The large variety of mechanisms involved in cellular migration as well as large time span that this process occupies during brain development may help explain some of the clinical heterogeneity observed in ASD.