Multimodal MRI study of gray matter and functional connectivity abnormalities in adolescents with bipolar disorder

TL;DR

This study uses MRI to find brain differences in adolescents with bipolar disorder, focusing on gray matter and brain connectivity.

Contribution

The study integrates multiple MRI techniques to reveal functional and structural brain abnormalities specific to adolescent bipolar disorder.

Findings

Adolescents with BD showed ALFF and ReHo abnormalities in the default mode and salience networks.

Reduced functional connectivity was found between the right supramarginal gyrus and left middle frontal gyrus in BD patients.

Decreased gray matter volume was observed in the left cerebellum among BD adolescents.

Abstract

Adolescent bipolar disorder (BD) is a severe psychiatric condition characterized by mood instability, with significant impacts on social and cognitive functioning. Clarifying the neural mechanisms underlying BD during adolescence may aid early diagnosis and treatment.

We conducted a multimodal neuroimaging study integrating functional and structural MRI data to investigate alterations in spontaneous neural activity (amplitude of low-frequency fluctuation (ALFF) and regional homogeneity (ReHo)), seed-based resting-state functional connectivity (rsFC), and gray matter volume (GMV) in 69 adolescents with BD and 42 matched healthy controls (HCs). ALFF and ReHo were used to identify local functional abnormalities. Overlapping brain regions were selected as seeds for rsFC analysis. Voxel-based morphometry (VBM) was performed to detect GMV differences. Correlations between imaging measures and clinical symptom scores (HAMD, HAMA, YMRS) were assessed.

Compared to HCs, BD patients exhibited significant abnormalities in the ALFF within the default mode network (DMN) and the salience network (SN). ReHo was also altered in the SN. Seed-based rs-FC analysis revealed reduced connectivity between the right supramarginal gyrus and the left middle frontal gyrus, which are key nodes of the frontoparietal network (FPN). VBM analysis demonstrated decreased GMV in the left cerebellum. No significant correlations were found between imaging measures and clinical scale ratings.

Our findings suggest that adolescent BD is characterized by functional abnormalities within DMN and FPN, as well as cerebellar gray matter atrophy. Disrupted structure–function coupling in these regions may reflect possible neurobiological mechanisms underlying BD during adolescence.

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