Neural correlates of cognitive fatigue in multiple sclerosis using functional MRI

Area of Science:

• Neuroscience
• Neurology
• Medical Imaging

Background:

• Fatigue is a primary symptom in multiple sclerosis (MS).
• The behavioral and neural underpinnings of MS-related fatigue remain poorly understood.
• Existing models suggest basal ganglia involvement in central fatigue.

Purpose of the Study:

• To investigate the behavioral and neural correlates of cognitive fatigue in MS.
• To examine brain activity patterns during a cognitive task in individuals with MS compared to healthy controls.
• To test the hypothesis that MS fatigue is associated with increased cerebral activation over time.

Main Methods:

• Utilized functional magnetic resonance imaging (fMRI) to monitor brain activity.
• Employed a novel approach to assess cognitive fatigue through objective behavioral performance (mSDMT).
• Compared brain activation patterns in 15 persons with MS and 15 healthy controls during a processing speed task.

Main Results:

• No significant difference in task accuracy was found between groups.
• The MS group exhibited significantly slower performance, indicating behavioral fatigue.
• Increased brain activation across time in the MS group was observed in the basal ganglia, frontal, parietal, thalamus, and occipital regions.

Conclusions:

• The findings support the Chaudhuri and Behan model of central fatigue.
• Increased activation in specific brain regions, particularly the basal ganglia, is associated with cognitive fatigue in MS.
• This study provides direct evidence for the role of non-motor basal ganglia functions in MS-related fatigue.