Interhemispheric functional connectivity in anorexia and bulimia nervosa

Area of Science:

• Neuroscience
• Psychiatry
• Medical Imaging

Background:

• Inter-hemispheric functional connectivity is crucial for cognitive and emotional regulation.
• Previous research on anorexia nervosa (AN) and bulimia nervosa (BN) has primarily focused on high-level processing, with limited investigation into inter-hemispheric connectivity anomalies.

Purpose of the Study:

• To investigate inter-hemispheric functional connectivity differences in patients with AN and BN compared to healthy controls (HC).
• To explore potential correlations between functional connectivity and structural brain asymmetries or white matter integrity.

Main Methods:

• Utilized resting-state functional MRI (fMRI) to assess voxel-mirrored homotopic connectivity (VMHC) and regional inter-hemispheric spectral coherence (IHSC).
• Analyzed T1-weighted and diffusion tensor imaging MRI scans to correlate VMHC with gray matter asymmetry and fractional anisotropy (FA) of the corpus callosum.
• Compared connectivity patterns in 15 AN patients, 13 BN patients, and 16 HC.

Main Results:

• AN patients exhibited reduced VMHC in the cerebellum, insula, and precuneus compared to HC.
• BN patients showed reduced VMHC in the dorsolateral prefrontal and orbitofrontal cortices compared to HC.
• Inter-hemispheric functional connectivity was generally higher in the 'Slow-5' band across regions, except for the insula, in patients versus controls. No significant group differences were found in structural asymmetries or VMHC-FA correlations.

Conclusions:

• AN and BN are associated with reduced inter-hemispheric functional connectivity in brain regions vital for self-referential processing, cognitive control, and reward, independent of structural changes.
• These functional anomalies may represent novel markers for understanding the aberrant neural mechanisms in the acute phase of AN and BN.
• The findings highlight the importance of studying inter-hemispheric communication in the neurobiology of eating disorders.