Cerebellar structure is abnormal in schizophrenia and deviates from bipolar disorder

Area of Science:

• Neuroimaging
• Neuroanatomy
• Psychiatric Disorders

Background:

• The cerebellum is increasingly recognized for its role in cognitive and emotional processing.
• Structural and functional cerebellar abnormalities are consistently reported in schizophrenia spectrum disorders.
• Posterior regions of the cerebellum, specifically Crus I and II, are most frequently implicated.

Purpose of the Study:

• To identify distinct cerebellar structural networks using source-based morphometry (SBM).
• To investigate patterns of gray matter differences in the cerebellum across individuals with schizophrenia (SZ), bipolar disorder with psychotic features (BDwP), and healthy controls (HC).
• To explore the relationship between identified cerebellar networks, cognitive performance, and diagnostic group.

Main Methods:

• Applied source-based morphometry (SBM) and voxel-based morphometry (VBM) to cerebellar structural MRI data from the Psychosis Human Connectome Project (P-HCP).
• Utilized the GIFT Toolbox for independent component analysis (ICA) to identify covarying gray matter networks.
• Analyzed data from 168 participants (85 SZ, 36 BDwP, 47 HC).

Main Results:

• One significant cerebellar network (IC) differentiated SZ from HC and BDwP (p < 0.05, Bonferroni-corrected).
• This network involved vermis VIIIa, bilateral Crus I, and right lobule IX with differential loadings.
• Voxel-based morphometry revealed reduced gray matter in specific regions of this network in SZ. Composite cognitive performance correlated with gray matter volume and network loadings.

Conclusions:

• A specific cerebellar structural network effectively differentiates schizophrenia from bipolar disorder and healthy controls.
• These findings underscore the cerebellum's unique contribution to the neurobiology of schizophrenia.
• The identified network's integrity is associated with cognitive performance in psychosis.