Anomalies of asymmetry of pyramidal cell density and structurein dorsolateral prefrontal cortex in schizophrenia

BackgroundStudies suggest that neuronal density in left dorsolateral prefrontalcortex is increased in schizophrenia.AimsTo replicate these findings and extend them to both hemispheres.MethodNeuronal density, size and shape were estimated in the prefrontal cortex(Brodmann area 9) of the left and right hemispheres of brains takenpostmortem from 10 people with schizophrenia and 10 without mentalillness (6 men, 4 women in both groups).ResultsOverall neuronal density (individually corrected for shrinkage) did notdiffer between the groups. In the control brains, density was generallygreater in the left than the right hemisphere, the reverse was seen inthe schizophrenia brains; this loss or reversal of asymmetry was mostsignificant in cortical layer 3. Pyramidal neurons in this cell layerwere significantly larger on the left and more spherical in shape than onthe right side in control brains, but size and shape did not differbetween the two sides in schizophrenia. Non-pyramidal and glial celldensities were unchanged.ConclusionsWe failed to find an increase in neuronal density, but found evidence ata cellular level of loss or reversal of asymmetry, consistent with thehypothesis of a primary change in the relative development of areas ofheteromodal association cortex in the two hemispheres.