NEURON AND GLIAL CELL NUMBERS IN THE MEDIODORSAL THALAMIC NUCLEUS IN BRAINS OF SCHIZOPHRENIC SUBJECTS

Abstract

Several stereological studies of schizophrenic subjects have shown reduction in both the total number of neurons and in the total volume of the mediodorsal thalamic nucleus (MD). This is in contrast to other studies in that no differences have been found. Using systematic random sampling and an optical fractionator design, the total number of neuron and glial cells in the MD subdivisions: parvocellular (MDPC), magnocellular (MDMC), and densocellular (MDDC) were counted in brains from 9 schizophrenic and 8 control subjects. The control subjects were age, height and body-weight matched to the schizophrenic subjects. We found the neuronal numbers in the schizophrenic subjects to range more than a factor of two, from 3.68 to 9.22 x 106. This is in contrast to the control subjects, who ranged from 5.24 to 7.10 x 106 in neuronal cell numbers. Within our inhomogeneous sample, some schizophrenic subjects thus exhibited relative high total neuron numbers in MD, while others exhibited relative low neuron numbers. The result is in line with the heterogeneity of this severe mental disease and may help to explain why different research groups get different results. The major limitation in this study is the small number of brains of schizophrenic subjects with a high degree of inhomogeneity in length of disease and age of onset. The debates of the comparison of the neurons in the MD in brains of schizophrenic subjects and control subjects and the possible impact of this variance on the disease are still not complete.