Brain networks disconnection in early multiple sclerosis cognitive deficits: an anatomofunctional study

Area of Science:

• Neuroscience
• Radiology
• Neurology

Background:

• Cognitive impairment is a common early symptom in multiple sclerosis (MS).
• Understanding the neurobiological underpinnings of early cognitive dysfunction is crucial for timely intervention.
• Resting-state functional connectivity and structural damage are key areas of investigation.

Purpose of the Study:

• To investigate changes in resting-state functional connectivity and structural damage in early relapsing MS patients with cognitive impairment.
• To identify specific brain networks and regions affected by cognitive dysfunction.
• To explore the relationship between structural damage and altered functional connectivity.

Main Methods:

• Prospective study of relapsing MS patients (3-5 years disease duration) categorized into cognitively impaired (CI) and cognitively preserved (CP) groups.
• Multimodal 3T MRI including anatomical, diffusion, and resting-state functional MRI.
• Neuropsychological evaluation to assess cognitive function across multiple domains.

Main Results:

• Cognitively impaired MS patients exhibited higher white matter lesion load and gray matter atrophy compared to cognitively preserved patients.
• Decreased functional connectivity was observed in the default mode network (DMN) and attentional networks (ATT) in CI patients compared to CP patients.
• Functional connectivity between the medial prefrontal cortex (MPFC) and posterior cingulate cortex (PCC) within the DMN was altered in CI patients, with PCC atrophy predicting this disconnection.

Conclusions:

• Disconnection within the DMN and ATT networks is associated with cognitive impairment in early MS.
• Structural damage, particularly PCC atrophy, contributes to altered functional connectivity in key brain networks.
• These network alterations may hinder the brain's ability to compensate for widespread structural damage in MS.