Summary: Changes in functional connectivity within the fatigue network occur in response to cognitive fatigue.
Source: Kessler Foundation
Kessler Foundation researchers have demonstrated changes in the functional connectivity within the ‘fatigue network’ in response to cognitive fatigue.
The authors are Glenn Wylie, DPhil, Brian Yao, PhD, Helen M. Genova, PhD, Michele H. Chen, PhD, and John DeLuca, PhD, of Kessler Foundation. All have faculty appointments at Rutgers New Jersey Medical School. Dr. Wylie is also a research scientist at The Department of Veterans’ Affairs War-related Injury and Illness Study Center at the New Jersey Healthcare System.
Cognitive fatigue, a troublesome symptom among healthy and clinical populations, is a major research focus at Kessler Foundation. With this study, Foundation scientists extended their exploration of the ‘fatigue network’, a set of brain regions associated with cognitive fatigue, comprising the striatum of the basal ganglia, the dorsolateral prefrontal cortex, the ventro-medial prefrontal cortex, and the anterior sula.
Understanding the underlying mechanisms of cognitive fatigue is essential to the development of effective interventions for people with disabling fatigue caused by multiple sclerosis, Gulf War Illness, brain injury, chronic fatigue syndrome and other conditions.
The study was conducted at the Rocco Ortenzio Neuroimaging Center at Kessler Foundation, a specialized facility dedicated solely to rehabilitation research. The team induced cognitive fatigue in 39 healthy volunteers while they underwent functional MRI of their brain activation patterns.
The participants’ fatigue in response to multiple runs of challenging tasks of working memory was measured using a visual analogue scale of fatigue (VAS-F). Researchers found that as cognitive fatigue increased, there was a decline in the connectivity among the regions that make up the fatigue network, and an increase in connectivity between the network and more posterior regions.
Dr. Wylie, director of the Ortenzio Center, commented on the results of this task-based functional neuroimaging paradigm: “Our findings provide further evidence for a functionally connected ‘fatigue network’ in the brain. More importantly, we have shown for the first time that this functional network connectivity changes in association with cognitive fatigue,” he emphasized. “This promises to accelerate progress toward effective interventions aimed at relieving debilitating fatigue.”
Funding: New Jersey Commission for Brain Injury Research (10.005.BIR1 to GW), The Department of Veterans’ Affairs (5I01CX000893 to GW), and Kessler Foundation.
About this neuroscience research news
Source: Kessler Foundation Contact: Carolann Murphy – Kessler Foundation Image: The image is in the public domain
Using functional connectivity changes associated with cognitive fatigue to delineate a fatigue network
Cognitive fatigue, or fatigue related to mental work, is a common experience. A growing body of work using functional neuroimaging has identified several regions that appear to be related to cognitive fatigue and that potentially comprise a “fatigue network”. These include the striatum of the basal ganglia, the dorsolateral prefrontal cortex (DLPFC), the dorsal anterior cingulate cortex (dACC), the ventro-medial prefrontal cortex (vmPFC) and the anterior insula.
However, no work has been conducted to assess whether the connectivity between these regions changes as a function of cognitive fatigue. We used a task-based functional neuroimaging paradigm to induce fatigue in 39 healthy individuals, regressed the signal associated with the task out of the data, and investigated how the functional connectivity between these regions changed as cognitive fatigue increased.
We observed functional connectivity between these regions and other frontal regions largely decreased as cognitive fatigue increased while connectivity between these seeds and more posterior regions increased. Furthermore the striatum, the DLPFC, the insula and the vmPFC appeared to be central ‘nodes’ or hubs of the fatigue network.
These findings represent the first demonstration that the functional connectivity between these areas changes as a function of cognitive fatigue.