Quantitative cytoarchitectural studies of the cerebral cortex of schizophrenics

Quantitative morphometric determinations of neuronal and glial density, neuron-glia ratios, and neuronal size were performed in the prefrontal, anterior cingulate, and primary motor cortex of ten controls and ten schizophrenics diagnosed by Feighner criteria under blind conditions to assess whether neuronal degeneration had occurred. Stepwise multiple regression and multiple classification analyses were used to evaluate the effect of potential confounding variables such as age, postmortem interval, fixation, hypoxia, and neuroleptic exposure on the measures studied. The neuronal density was significantly lower in layer VI of the prefrontal, layer V of the cingulate, and layer III of motor cortex. There was also a trend toward fewer neurons in most layers of both prefrontal and motor cortex, although by discriminant analysis this generalized pattern was significant only for the prefrontal area. The glial density also tended to be lower throughout most layers of all three cortical regions. There were no differences in the neuron-glia ratios or neuronal size between the two groups. The data do not support the presence of neuronal degeneration in schizophrenic cortex as it is conventionally described by neuropathologists, but do suggest the possibility that cytoarchitectural variations in cortical structure might exist in this group of schizophrenics.