Neural mechanisms underlying state mental fatigue in multiple sclerosis: a pilot study

Area of Science:

• Neuroscience
• Cognitive Science
• Medical Imaging

Background:

• Mental fatigue is a common and debilitating symptom in multiple sclerosis (MS).
• The neuroimaging correlates of transient mental fatigue in MS are not well understood.
• Understanding brain activation patterns during cognitive tasks is crucial for managing MS-related fatigue.

Purpose of the Study:

• To investigate the neuroimaging underpinnings of state mental fatigue in individuals with MS.
• To compare brain activation patterns during varying cognitive loads between persons with MS and healthy controls.
• To explore the relationship between cognitive load, mental fatigue, and brain resource allocation.

Main Methods:

• Functional magnetic resonance imaging (fMRI) was used to measure brain activity.
• Participants performed a rapid information processing task with high and low cognitive loads.
• State mental fatigue was assessed using the Visual Analog Scale of Fatigue before and after tasks.

Main Results:

• Healthy controls recruited more anterior brain regions (e.g., frontal, insula) with increased fatigue and cognitive load, showing improved performance.
• Persons with MS showed less recruitment of anterior regions and continued activation of posterior areas (e.g., precuneus, occipital gyrus).
• MS group did not demonstrate performance improvements with increased cognitive load or fatigue.

Conclusions:

• Individuals with MS may exhibit less efficient neural resource allocation compared to healthy controls when facing increased task demands.
• Inefficient brain activation patterns in MS could contribute to heightened mental fatigue.
• Further research with larger sample sizes is needed to confirm these pilot findings.