502. Reduced neuropil in the auditory cortex of patients with schizophrenia

Abstract

It has been hypothesized that there is a reduction in the interneuronal space in the prefrontal cortex in Schizophrenia (Selemon et al., 1995). Because the spatial distribution of neurons in the cortex is focused around the minicolumn, we anticipated that the hypothesis of reduced interneuronal space in schizophrenia could be independently tested by analysis of these units. Initial studies have focused on prefrontal cortex, areas 9 and 46. We investigated a small population of normal controls (n = 13) and schizophrenia patients (n = 7), diagnosed according to DSM III—R criteria. Patients and controls were age and sex matched. Photomicrographs of the posterior portion of the superior temporal gyrus (area Tpt) were taken at 100× magnification. Among the features examined was the amount of neuropil space in the periphery of cell columns where local circuits, synapses, and dendritic branches predominate. We also measured the amount of spacing between cell soma within the cell-dominant portion of the columns, and the distance separating cell columns in the horizontal plane. All the values for spacing distances and neuropil space were less in schizophrenic brains. Significant findings resulted when we combined the data for the right and left sides of both schizophrenics and controls. We conclude that neuropil space is decreased in Tpt in schizophrenia patients, with the greatest reduction occurring within the core of the cell column. The finding infers a generalized distribution of interneuronal space reduction in the schizophrenic brain.