Neuronal migration abnormality refers to different degrees of developmental malformations of the brain tissue, including anencephaly-macroglossal gyrus malformation, gray matter heterotopia, encephalocele malformation, multiple cerebellar gyrus malformation, hemihypophyseal megalencephaly, and localized cortical dysplasia, due to the obstruction of neuronal cells’ movement from the embryonic germinal matrix to the surface of the brain during the development of the cerebral cortex for a variety of reasons. Each type has specific etiology, pathologic changes and imaging features. What are the causes of neuronal migration anomalies? The following are the causes of neuronal migration abnormalities: anencephaly-macroglossal gyrus malformations, gray matter heterotopia, schizencephaly, multiple cerebellar gyrus malformations, hemisphere macroglossal malformations, and localized cortical dysplasia. The most common diagnoses of neuronal migration abnormalities are cerebral palsy, epilepsy, and mental retardation.