Brain imaging reveals clues about chronic fatigue syndrome

May 23, 2014
Credit: Vera Kratochvil/public domain

A brain imaging study shows 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 syndrome had less activation of the , as measured by fMRI (functional ). This reduction of basal ganglia activity was also linked with the severity of fatigue symptoms.

According to the Centers 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.

The results are scheduled for publication in the journal PLOS One.

"We chose the basal ganglia because they are primary targets of inflammation in the ," 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."

Miller is William P. Timmie professor of psychiatry and behavioral sciences at Emory University School of Medicine. The study was a collaboration among researchers at Emory University School of Medicine, the CDC's Chronic Viral Diseases Branch, and the University of Modena and Reggio Emilia in Italy. The study was funded by the CDC.

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 published studies by Emory researchers, 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."

Treatment implications might include the potential utility of medications to alter the body's immune response by blocking inflammation, or providing drugs that enhance basal ganglia function, he says.

The researchers compared 18 patients diagnosed with with 41 healthy volunteers. The 18 patients were recruited [not referred] based on an initial telephone survey followed by extensive clinical evaluations. The clinical evaluations, which came in two phases, were completed by hundreds of Georgia residents. People with major depression or who were taking antidepressants were excluded from the imaging study, although those with anxiety disorders were not.

For the brain imaging portion of the study, participants were told they'd win a dollar if they correctly guessed whether a preselected card was red or black. After they made a guess, the color of the card was revealed, and at that point researchers measured blood flow to the basal ganglia.

The key measurement was: how big is the difference in activity between a win or a loss? Participants' scores on a survey gauging their levels of fatigue were tied to the difference in basal ganglia activity between winning and losing. Those with the most fatigue had the smallest changes, especially in the right caudate and the right globus pallidus, both parts of the basal ganglia.

Ongoing studies at Emory are further investigating the impact of inflammation on the basal ganglia, including studies using anti-inflammatory treatments to reduce and loss of motivation in patients with depression and other disorders with including cancer.

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1.8 / 5 (5) May 23, 2014
There would be no cfs if people had to get up and hunt for their food. It would either yield to the demands of survival and the requisite exercise or it would quickly be selected to extinction.

I am not passing judgement I am making an observation. The gene pool has accumulated a great deal of detritus due to agriculture and technology. How long would a hemophiliac live in the wild? Would a schizophrenic survive long enough to reproduce? Does any wild species exhibit such a wide range of intellectual ability?

More evidence that the modern human is the result of very unnatural selection. We didn't evolve - we developed.
Diogenes Tha Dogg
3.4 / 5 (5) May 23, 2014
There would be no cfs if people had to get up and hunt for their food. It would either yield to the demands of survival and the requisite exercise or it would quickly be selected to extinction.

Holy hell, you are a complete idiot.

1.) You pick hemophilia rather than a REAL problem, like Tay-Sachs, because you don't really know about genetic diseases.
2.) You try to pin schizophrenia entirely on genetics. If you know the neurobiological basis of schizophrenia, then you should tell the world's psychiatry community, because they are dying to find out.
3.) You completely fail to understand evolution. For example, how do you account for the sickle cell / malaria duality, and is that "evolution" or "development"? Since I know you don't know the answer, I'll help you: it came about by "adaptation" and "terrible luck", which are parts of "evolution".
4.) Discovering that CNS stimulants augment fatigue is the PERFECT example of "development" by your weird definition.
3 / 5 (2) May 24, 2014
pick hemophilia rather than a REAL problem
So bleeding out in the woods isn't a real problem?

"Hemophilia is an X-linked disorder. Hemophilia is more common in males because males have only one X chromosome."

-Curiously, many dogs are born with it.
You try to pin schizophrenia entirely on genetics
Development within the context of tribes and technology and chronic overpopulation has selected for human brains which are increasingly large and complex. It has doubled in size in a very short time.

This has resulted in an organ which is damage- and defect-prone, and energy-hungry. Our brains begin to detrioriate shortly after adolescence because during the Pleistocene we rarely survived into our 30s.

Additionally we have been culturally selected for certain specific types of insanity such as the ability to believe in fantasy beings and central authority. And we are chronically malnourished and poisoned and infected.

Mental illness is thus prevalent in our species.
3 / 5 (2) May 24, 2014
Hemophiliacs and schizophrenics would not do well hunting, foraging, avoiding danger, and fighting off predators. But in modern society they are nurtured and can earn good livings as politicians and novelists and artists and philosophers.

Similarly, cfs sufferers would have more pressing problems in the wild such as predation and starvation. And of course tribal members who do not pull their weight are tarred and feathered.

Perhaps calorie restriction (CR) would prove effective in treating cfs or PTSD or ADD or other such mental disorders? Worth a try. Perhaps the pain and trauma of shock therapy, rather than the scrambling of neural impulses, is what really motivates the depressive? Because it simulates the sensory input he would receive in response to his behavior, in the wild.

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