The XI National Congress of the Italian Society of Psychopathology: Psychiatric therapy. A problem of freedom - Rome, February 21-25, 2006: SOPSI Prize 2006. Reduced neuronal density in the fusiform cortex of schizophrenic subjects

Background: Reduced fusiform gyrus volume has been reported in MRI studies of schizophrenia. Evidence from brain lesions suggests the fusiform cortex is involved in object naming and categorisation. Reduced fMRI activation is seen during emotion recognition tasks in schizophrenia. Methods: We assessed cell size, shape and density of pyramidal and non-pyramidal neurons and glial cell density in layers 3 and 5 of fusiform cortex from 11 (6 females, 5 males) control subjects and 10 (5 females, 5 males) subjects with schizophrenia. Systematic random sampling in the left and right hemispheres provided size and shape of 120 pyramidal and 120 non-pyramidal cells per case by outlining at a point where the nucleolus was clearly visible. For estimating cell densities, 450 to 600 cells were counted per subject. Results: Pyramidal cell density was reduced in schizophrenia in both layers, in both hemispheres with no effect by sex. Non-pyramidal cell density was reduced in layer 3, in the left hemisphere and this was greatest in females. Non-pyramidal cells were larger in schizophrenia. Glial cell density was unchanged. Conclusions: Reduced pyramidal and non-pyramidal neuron density in the fusiform cortex relates to findings of reduced fusiform cortex volume and is consistent with reduced cell density in other regions reported in the literature. Pyramidal cell loss in fusiform cortex may contribute to reduced activation in imaging studies. Non-pyramidal neurons may be enlarged in schizophrenia as compensation for reduced density.