Brain Imaging Study Reveals Clues about Chronic Fatigue Syndrome

Amy Taylor May 28, 2014

Researchers from Emory University School of Medicine, in collaboration with CDC’s Chronic Viral Diseases Branch, and the University of Modena and Reggio Emilia in Italy, found that patients with chronic fatigue syndrome may have reduced responses, compared with healthy controls, in a region of the brain connected with fatigue. The findings suggest that chronic fatigue syndrome is associated with changes in the brain involving brain circuits that regulate motor activity and motivation.

Compared with healthy controls, patients with chronic fatigue syndrome had less activation of the basal ganglia, as measured by fMRI (functional magnetic resonance imaging). This reduction of basal ganglia activity was also linked with the severity of fatigue symptoms.

According to the Centres for Disease Control and Prevention, chronic fatigue syndrome is a debilitating and complex disorder characterized by intense fatigue that is not improved by bed rest and that may be worsened by exercise or mental stress.

"We chose the basal ganglia because they are primary targets of inflammation in the brain," says lead author Andrew Miller, MD. "Results from a number of previous studies suggest that increased inflammation may be a contributing factor to fatigue in CFS patients, and may even be the cause in some patients."

The basal ganglia are structures deep within the brain, thought to be responsible for control of movements and responses to rewards as well as cognitive functions. Several neurological disorders involve dysfunction of the basal ganglia, including Parkinson’s disease and Huntington’s disease, for example.

In previous studies by the same research team, it was found that people taking interferon alpha as a treatment for hepatitis C, which can induce severe fatigue, also show reduced activity in the basal ganglia. Interferon alpha is a protein naturally produced by the body, as part of the inflammatory response to viral infection. Inflammation has also been linked to fatigue in other groups such as breast cancer survivors.

"A number of previous studies have suggested that responses to viruses may underlie some cases of CFS," Miller says. "Our data supports the idea that the body’s immune response to viruses could be associated with fatigue by affecting the brain through inflammation. We are continuing to study how inflammation affects the basal ganglia and what effects that has on other brain regions and brain function. These future studies could help inform new treatments."

Currently, Miller and his team are investigating the impact of inflammation on the basal ganglia, including studies using anti-inflammatory treatments to reduce fatigue and loss of motivation in patients with depression and other disorders with inflammation including cancer.

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