Structural alteration of neurons in schizophrenia and its relation with auditory hallucination

Volumetric changes in the superior temporal gyrus and anterior cingulate cortex have been repeatedly reported in studies on schizophrenia. Tractography and functional magnetic resonance imaging studies have suggested that alterations in connectivity involving the superior temporal gyrus and the anterior cingulate cortex are relevant to psychotic symptoms of schizophrenia.

We analyzed nanometer-scale three-dimensional structures of brain tissues of the superior temporal gyrus and the anterior cingulate cortex in eight schizophrenia and eight control cases and evaluated structural parameters of their neurons. We then examined the relation between the neuronal parameters and clinical information including auditory hallucination score.

The obtained results indicated that 1) neurites become thin and tortuous in schizophrenia and that 2) somata become small in schizophrenia. The frequency distribution of neurite curvatures had a broad profile in the schizophrenia cases, whereas the control cases showed sharp peaks. In the scatter diagram of the standard deviation of neurite curvatures, the schizophrenia and control cases formed separate clusters, indicating that all 16 cases analyzed in this study can be assigned to either the schizophrenia or control group simply by using the diagram. The cingulate/temporal ratio of the standard deviation of neurite curvatures showed a strong positive correlation with the auditory hallucination score.

The structural alteration of neurites observed in the schizophrenia cases should influence the function of affected brain areas by hindering communication between distant neurons. We suggest that the interplay of the temporal and cingulate cortices in the whole-brain network is relevant to auditory hallucination.