Prenatal developmental disturbances in the limbic allocortex in schizophrenics.

Sixty-four autopsied brains of schizophrenic patients were neuropathologically examined and compared with 10 brains of non-schizophrenic controls. Clinical diagnoses were established retrospectively according to the Research Diagnostic Criteria and the International Classification of Diseases. We found: brains without deviations of the sulcogyral pattern of the temporal lobe or abnormal gross configuration (n = 22); brains with abnormal sulcogyral pattern of the temporal lobe or abnormal gross configuration (n = 42): with definite cytoarchitectonic abnormalities of the rostral entorhinal region in the parahippocampal gyrus and, in 16 cases only, in the ventral insular cortex (n = 20); with equivocal changes of the cytoarchitecture in these two regions (n = 22). Generally, these anatomical abnormalities were asymmetric. The histological findings in the two limbic regions consisted mainly of poorly developed structure in the upper layers, with a heterotopic displacement of single groups of nerve cells in the entorhinal region. Particularly, the disturbed structure of the second layer Pre-alpha in medial and central fields of the entorhinal region, situated in the parahippocampal gyrus (group 2a), suggests a disturbance of neuronal migration in a later phase of cortical development.