The Fatigued Brain: Associations of Chronic Fatigue and Acute Mental Fatigue on Resting-State Functional Connectivity

Fatigue is common among medical students and it is associated with impaired cognitive functions. In the present study we used fMRI to investigate intrinsic brain function associated with fatigue in medical students. We compared medical students with and without chronic fatigue (N = 25 per group, all females, mean age = 22 years). In addition, we manipulated acute fatigue and compared the groups on effects of a fatigue inducing session and a non-fatiguing control session. We investigated whole brain functional connectivity and targeted the default mode network (DMN) and all networks that covered areas specifically associated with executive function and attention. Our results showed that chronically fatigued students were characterized by reduced resting state functional connectivity in the DMN, ventral stream network and dorsal attention network. Moreover, the anterior and posterior DMN were less widespread in chronically fatigued students (as indicated by a significantly lower number of supra-threshold voxels). The DMN and ventral stream network also showed functional connectivity changes in response to the fatigue manipulation. This manipulation affected the groups differently on functional connectivity in the right frontoparietal network. Based on these results, we conclude that fatigue in medical students involves functional organization changes that are possibly linked to reductions in a broad range of cognitive control functions. Further research should provide more insight into the nature of this link. CONNECTIVITY CHANGES IN FATIGUED STUDENTS | 5