Brain morphological and functional features in cognitive subgroups of schizophrenia

Abstract

Aim: Previous studies have reported different brain morphologies in different cognitive subgroups of patients with schizophrenia. We aimed to examine the brain structures and functional connectivity in these cognitive subgroups of schizophrenia.

Methods: We compared brain structures among healthy controls and cognitively deteriorated and preserved subgroups of patients with schizophrenia according to the decline in IQ. Connectivity analyses between subcortical regions and other brain areas were performed using resting-state functional magnetic resonance imaging among the groups.

Results: Whole brain and total cortical gray matter, right fusiform gyrus, left pars orbitalis gyrus, right pars triangularis, left superior temporal gyrus and left insula volumes, and bilateral cortical thickness were decreased in the deteriorated group compared to the control and preserved groups. Both schizophrenia subgroups had increased left lateral ventricle, right putamen and left pallidum, and decreased bilateral hippocampus, left precentral gyrus, right rostral middle frontal gyrus, and bilateral superior frontal gyrus volumes compared with controls. Hyperconnectivity between the thalamus and a broad range of brain regions was observed in the deteriorated group compared to connectivity in the control group, and this hyperconnectivity was less evident in the preserved group. We also found hyperconnectivity between the accumbens and the superior and middle frontal gyri in the preserved group compared with connectivity in the deteriorated group.

Conclusion: These findings provide evidence of prominent structural and functional brain abnormalities in deteriorated patients with schizophrenia, suggesting that cognitive subgroups in schizophrenia might be useful biotypes to elucidate brain pathophysiology for new diagnostic and treatment strategies.

Keywords: brain functional connectivity; brain morphology; cognitive decline; cognitive subgroup; schizophrenia.

Figure 1

Volume differences in brain structures among groups. The mean differences in brain structures across healthy controls (HC) and individuals with schizophrenia who show preserved IQ (P) or deteriorated IQ (D). Error bars are the standard deviation of the mean (SD). Statistical significance was defined for post‐hoc comparisons at P < 0.05.

Figure 2

Volume differences in subcortical brain structures among groups. The mean differences in subcortical brain volume across healthy controls (HC) and individuals with schizophrenia who show preserved IQ (P) or deteriorated IQ (D). Error bars are the standard deviation of the mean (SD). Statistical significance was defined for post‐hoc comparisons at P < 0.05.

Figure 3

Hyperconnectivity between the thalamus and widespread cortical areas in deteriorated patients. Hyperconnectivity between the (a) left thalamus and (b) right thalamus and other brain areas are shown. Red indicates significant hyperconnectivity in the deteriorated patients compared with connectivity in healthy controls (HC), green indicates significant hyperconnectivity in the preserved group compared with connectivity in HC, and yellow indicates merged areas of red and green. The threshold for significance was set at a cluster‐level family‐wise‐error‐corrected P < 0.05.

Figure 4

Hyperconnectivity between the accumbens and the frontal and temporal gyri in preserved patients. Hyperconnectivity between the right accumbens and other brain areas in preserved patients compared with connectivity in (a) healthy controls (HC), (b) deteriorated patients compared with that in HC, and (c) preserved patients compared with that in deteriorated patients are shown. Green indicates significant hyperconnectivity in the preserved patients compared with connectivity in HC. Red indicates significant hyperconnectivity in the deteriorated patients compared with connectivity in HC. Light blue indicates significant hyperconnectivity in the preserved patients compared with connectivity in deteriorated patients. The threshold for significance was set at a cluster‐level family‐wise‐error‐corrected P < 0.05.