Patients with chronic fatigue syndrome (CFS) had significantly less activation of the basal ganglia in response to a known stimulus compared with a control group, American researchers report.

Brain imaging during a simulated reward task showed reduced activation in the right caudate and right globus pallidus of patients with CFS. The reduction in activity (in the CFS group) correlated with measures of fatigue; the greater the fatigue, the greater the reduction in activation.

Given similar findings in patients treated with the antiviral cytokine interferon-alpha, inflammatory cytokines might be involved in chronic fatigue syndrome.

Fatigue is a common feature in neurologic disorders that involve the basal ganglia, such as Parkinson’s disease and multiple sclerosis. The basal ganglia, which mediate motor activity and motivation, are vulnerable to the effects of pro-inflammatory cytokines, and the effects of interferon-alpha on the basal ganglia correlate with fatigue.

Because dopamine is the primary neurotransmitter in basal ganglia, dopamine metabolism may be important in CFS.

Decreased basal ganglia activation in chronic fatigue syndrome subjects is associated with increased fatigue Elizabeth R Unger et al