Abnormally high neuronal density in the schizophrenic cortex. A morphometric analysis of prefrontal area 9 and occipital area 17.

In the past two decades, gross morphologic changes have been uncovered in the schizophrenic brain, eg, increased ventricular width and decreased cortical volume; however, relatively little is known about the area-specific and laminar density of cells in the schizophrenic cortex, particularly in prefrontal areas. A direct, three-dimensional counting method was used to determine cell density in 16 brains from patients with schizophrenia, 19 from normal subjects, six from patients with schizoaffective disorder, and nine from patients with advanced-stage Huntington's disease. Increased neuronal density was found in prefrontal area 9 (17%) and occipital area 17 (10%) in the schizophrenic brains. In area 9, neuronal density was increased in layers III to VI; cell packing of pyramidal and nonpyramidal neurons was elevated. Cortical thickness in the schizophrenic brains was slightly but not significantly reduced in both areas, with a disproportionate reduction in layer V in area 9. In contrast, brains with Huntington's disease exhibited markedly higher glial density (50%) and drastically reduced cortical thickness (28%). Abnormally high density in the cerebral cortices of schizophrenics suggests that neuronal atrophy is the anatomic substrate for deficient information processing in schizophrenia.