Oligodendrocyte abnormalities in layer 5 in the inferior parietal lobule are associated with lack of insight in schizophrenia: A postmortem morphometric study

Background and Objectives: Previously we reported in layer 3 of the inferior parietal lobule a reduction in the numerical density of oligodendrocytes (Nv Ol), oligodendrocyte clusters (Nv OlC) in BA 39, and in the number of perineuronal oligodendrocytes (N PnOl) in BA 39/40 areas in schizophrenia. These changes were associated with lack of insight. We hypothesized that similar abnormalities might occur in layer 5 in BA 39/40, and they might be associated with lack of insight. Methods: We estimated the Nv Ol, the Nv OlC by optical disector method and the N PnOl in layer 5 in BA 39/40 in Nissl stained sections from 24 males with schizophrenia and 24 normal male controls from the Stanley Parietal Collection. The schizophrenia group was divided into three subgroups based on level of insight: poor, fair or good. Results: We found a significant deficit in the parameters measured in BA 39 in the schizophrenia group and in the subgroup of subjects having poor insight as compared to the control group. In BA 40 the Nv Ol and the Nv OlC were significantly lower in the schizophrenia group compared to controls, and the N PnOl was not changed. Each insight subgroup showed a decreased the Nv Ol and the Nv OlC compared to controls. There were no subgroup differences in BA 39/40. Conclusions: Schizophrenia is characterized by the reduction in the Nv Ol and the Nv OlC in layer 5 of BA 39/40. Oligodendrocyte abnormalities in BA 39 are associated with poor insight in schizophrenia. Received: 28 April 2015 Revised: 17 May 2015 Accepted: 17 Juny 2015 216 NATALYA A. URANOVA ET AL.