Aberrant interhemispheric homotopic functional and structural connectivity in amyotrophic lateral sclerosis

Area of Science:

• Neuroscience
• Neurology
• Medical Imaging

Background:

• Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease affecting the motor system.
• Microstructural changes in the corpus callosum (CC) are known in ALS, but interhemispheric connectivity is understudied.

Purpose of the Study:

• To investigate alterations in interhemispheric structural and functional connectivity in individuals with ALS.
• To elucidate the role of the corpus callosum in ALS pathophysiology.

Main Methods:

• Utilized diffusion tensor imaging (DTI) and resting-state functional MRI (rfMRI).
• Analyzed voxel mirrored homotopic connectivity (VMHC) and probabilistic fibre tracking to assess connectivity.
• Included 38 individuals with ALS and 35 healthy controls.

Main Results:

• Found reduced VMHC in ALS patients across multiple brain regions, including the precentral and postcentral gyri.
• Observed decreased interhemispheric structural connectivity in CC subregions II, III, and V in ALS.
• Correlated functional connectivity of bilateral precentral gyri with CC subregion III fractional anisotropy.

Conclusions:

• Provided direct evidence of impaired interhemispheric neural communication mediated by the CC in ALS.
• Offers a new perspective for understanding ALS pathophysiology.
• Highlights the importance of corpus callosum integrity in motor system function.