Fronto-striatal network activation leads to less fatigue in multiple sclerosis

BACKGROUND: The fronto-striatal network has been implicated in both fatigue, a common multiple sclerosis (MS) symptom, and goal attainment, which has been shown to reduce fatigue in healthy individuals.

OBJECTIVES: To investigate whether stimulation of the fronto-striatal network through goal attainment (potential monetary gain) leads to fatigue reduction in MS and healthy control (HC) participants.

METHODS: In all, 14 healthy and 19 MS participants performed a gambling task during functional magnetic resonance imaging (fMRI). Participants were presented with an opportunity to receive monetary reward during the outcome condition of the task but not during the no outcome condition. Self-reported fatigue measures were obtained after each condition and outside of the scanner. Structural alterations were also examined.

RESULTS: A significant decrease in fatigue was observed after the outcome condition compared to the no outcome condition in both groups. Significantly greater activation was observed in the ventral striatum in association with the outcome condition compared to the no outcome condition in both groups. Ventromedial prefrontal cortex showed significantly greater activation during the no outcome condition compared to the outcome condition with greater difference between conditions in the HC group.

CONCLUSION: This is the first functional neuroimaging study showing that stimulation of the fronto-striatal network through goal attainment leads to decreased on-task fatigue in MS and healthy participants.