Functional neuroimaging correlates of mental fatigue induced by cognition among chronic fatigue syndrome patients and controls. Neuroimage. 2007 Mar 3; [Epub ahead of print] Dane B. Cook [a, b, *], Patrick J. O'Connor [c], Gudrun Lange [d, e] and Jason Steffener [f] Affiliations: [a] Department of Veterans Affairs-William S. Middleton Memorial Veterans Hospital, Madison, WI 53706, USA [b] Department of Kinesiology, University of Wisconsin, Madison, WI 53706, USA [c] Department of Kinesiology, University of Georgia, Athens, GA 30602, USA [d] Department of Veterans Affairs-New Jersey Health Care System, East Orange, NJ 07018, USA [e] Department of Radiology, University of Medicine and Dentistry of New Jersey Medical School, Newark, NJ 07103, USA [f] Cognitive Neuroscience Division of the Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University, New York, NY 10032, USA [*] Corresponding author. 2000 Observatory Drive, Unit II Gym, Department of Kinesiology, University of Wisconsin-Madison, Madison, WI 53706, USA. Fax: +1 608 262 1656. Received 18 January 2007; revised 12 February 2007; accepted 13 February 2007. Available online 3 March 2007. NLM Citation: PMID: 17408973 The neural mechanisms underlying feelings of fatigue are poorly understood. The primary purpose of the study was to use functional magnetic resonance imaging (fMRI) to determine the association between feelings of mental fatigue and blood oxygen level dependent (BOLD) brain responses during a mentally fatiguing cognitive task. Healthy, non-fatigued controls and chronic fatigue syndrome (CFS) patients were included to determine the influence of chronic levels of fatigue on brain responses. We hypothesized that mental fatigue would be significantly related to brain activity during a fatiguing cognitive task but not during either a non-fatiguing motor (finger tapping) or cognitive (auditory monitoring) task. Patients (n=9) and controls (n=11) completed a finger tapping task, a simple auditory monitoring task and a challenging working memory task, designed to induce mental fatigue, while undergoing fMRI. Fatigue was measured prior to scanning and following each task during fMRI data collection. Results showed that mental fatigue was significantly related to brain activity during the fatiguing cognitive task but not the finger tapping or simple auditory monitoring tasks. Significant (p