Deficit of oligodendrocyte family cells in layer 5 of the dorsal anterior cingulate cortex in schizophrenia.

The deficit of oligodendrocyte family cells has commonly been implicated in the dysfunction of neuronal networks in schizophrenia. Previously we reported a significant deficit of oligodendrocytes (Ol) and oligodendrocyte clusters (OlC), containing differentiating oligodendrocyte progenitors, in the cortical hubs of fronto-parietal cognitive (FPN) and default mode (DMN) networks, and in the striatum which is a central relay of the numerous networks. Anterior cingulate cortex (ACC) is crucial for integration of cognitive and emotional processes in support of goal-directed behavior and it's connections with FPN, DMN and basal ganglia are altered in schizophrenia. Few studies have examined changes in Ol family cell numbers in the ACC in schizophrenia, however, decreased expression of myelin- and oligodendrocyte-related genes in the ACC are characteristic of schizophrenia. We used optical disector method to estimate the numerical density (Nv) of oligodendrocytes and oligodendrocyte clusters in layer 5 of dorsal ACC (dACC) in schizophrenia (18 cases per group) as compared to healthy controls (13 cases per group). A significant reduction in the Nv of oligodendrocytes (- 23%; p < 0.01) and NvOlC (- 28%, p = 0.012) was found in schizophrenia as compared to the control group. We found significant correlations between the NvOl and the NvOlC in both control (R = 0.9; p < 0.001) and schizophrenia groups (R = 0.77; p = 0.014). The deficits in the number of OL and OlC in layer 5 of dACC may be tightly linked with reduced reciprocal ACC-thalamic connectivity in patients brain which were reported strongly correlate with positive symptoms fundamental for schizophrenia.