Cortical Development and Thalamic Pathology in

In this article, morphological data suggesting that brain development may be altered in schizophrenia are reviewed in relation to the major events in neural development In the absence of severe defects in brain structure in individuals with schizophrenia, develop-mental processes governing the establishment, refine-ment, and maintenance of connections are potential sites of pathological involvement Alterations in con-nectional patterns are likely to result in activity-depen-dent changes in gene expression for molecules involved in the neurotransmission process, with functional con-sequences. Loss of cells in the thalamus may be pri-mary or secondary to cortical or other subcortical pathology. Loss of thalamic cells and/or of corticothal-amic inputs could lead to disintegration of thought processes by a failure in functional brain states depen-dent on collective oscillation of large ensembles of cor-tical and thalamic neurons. Schizophrenia Bulletin, 23(3):483-501,1997. Many theories have suggested that brain development is affected in schizophrenia and that the psychopathology of schizophrenia may derive from alterations of brain organi-zation secondary to defective ontogenesis. The develop-mental hypothesis of schizophrenia has its origins in stud-ies of psychomotor and neuropsychological development in individuals with schizophrenia and in children geneti-cally at risk for schizophrenia (Bender 1947; Bender an