Pyramidal soma size in the anterior cingulate cortex is small in schizophrenia and correlates with hallucination...

Volumetric reduction of gray matter has repeatedly been reported for schizophrenia. Although meta-analyses of imaging studies revealed the macroscopic reduction of the anterior cingulate cortex in schizophrenia, its mechanism at the cellular level has yet to be revealed. In this study, we analyzed neuronal soma structures of the anterior cingulate cortex of 8 schizophrenia and 8 control cases visualized with synchrotron radiation nano-CT. The analysis results indicated that the mean soma length of the schizophrenia group is 80 % of that of the control group (p = 0.00085). A scatter plot of the soma length versus the standard deviation of the neurite curvature indicated that the cases of this study can be distinguished into schizophrenia and control groups by using these two parameters. We also found that the hallucination score significantly correlates with the neuronal soma length (Pearson's r = -0.52, p = 0.037). We previously reported neurite thinning in the anterior cingulate cortex of schizophrenia cases. Soma downsizing along with the neurite thinning should cause the gray-matter shrinkage long observed for schizophrenia and can lead to malfunctioning of the corresponding cerebral areas.