Resting state sensorimotor functional connectivity in multiple sclerosis inversely correlates with transcallosal...

Area of Science:

• Neuroimaging
• Neurology
• Biophysics

Background:

• Multiple Sclerosis (MS) is characterized by white matter lesions, impacting both brain structure and function.
• Previous research suggests reduced functional connectivity in sensorimotor regions and correlations between white matter diffusivity and clinical deficits in MS.
• Magnetic Resonance Imaging (MRI) techniques offer potential for assessing both functional and anatomical connectivity in MS.

Purpose of the Study:

• To compare the anatomical connectivity of the transcallosal motor pathway with functional connectivity of the sensorimotor cortices in MS patients.
• To investigate the relationship between diffusion tensor imaging (DTI) measures of white matter integrity and resting-state functional connectivity (F(c)) using low-frequency BOLD fluctuations (LFBFs).

Main Methods:

• Combined high angular resolution diffusion imaging with functional MRI to define the transcallosal white matter pathway.
• Calculated diffusion measures (Fractional Anisotropy [FA], Mean Diffusivity [MD], lambda(1), lambda(2)) from probabilistic tracking maps.
• Assessed resting-state functional connectivity (F(c)) using LFBFs in 11 MS patients and 10 controls.

Main Results:

• A significant negative correlation was found between FA and F(c) in MS patients (r = -0.63, P < 0.04).
• Transverse diffusivity (lambda(2)) showed significant correlations with F(c) across all subjects (r = 0.42, P < 0.05 and r = -0.50, P < 0.02).
• No significant correlations were observed in control subjects or for other diffusion measures (MD, lambda(1)) in MS patients.

Conclusions:

• This study provides the first in vivo evidence correlating measures of anatomical connectivity with functional connectivity in MS using spontaneous LFBFs.
• The findings highlight the potential of combined DTI and resting-state fMRI to probe the relationship between white matter integrity and brain network function in MS.