Introduction
autoimmune, neurodegenerative disease, CF, fatigue, cognitive fatigue, cognitive impairment, CF disrupts feedback-based learning, goal-directed behavior, RRMS
MULTIPLE SCLEROSIS (MS)
Multiple sclerosis (MS) is an autoimmune, neurodegenerative disease that targets both white and gray matter in the central nervous system (A common debilitating symptom in MS is fatigue, with cognitive fatigue (CF) showing prevalence estimates as high as 90 % (Within the brain, CF is linked to altered functioning of cortico-striatal regions – including the ventral striatum (VS), caudate nucleus of the dorsomedial striatum, and prefrontal regions (These same cortico-striatal regions and connections also overlap with circuitry that regulates reward processing, reinforcement learning, and goal-directed behavior in NT individuals (While cognitive impairment across various domains has been reported in MS (The present study had two aims – 1) to examine whether state CF disrupts feedback-based learning in people with MS with high trait CF and 2) to investigate whether differences in cortico-striatal activity and connectivity exist between MS and NT individuals during feedback processing. Groups of RRMS and NT participants completed an fMRI paired-word association task (