Fibromyalgia syndrome (FM) is a chronic illness of indeterminate cause, a syndrome — that is a constellation of signs and symptoms observed in, and characteristic of, a single condition — and not a specific disease with clearly defined causes and treatment. FMS is typically characterized by moderate to severe musculoskeletal pain that can range through the entire body, frequently accompanied by fatigue, sleep disorders, restless legs syndrome, tension headaches, temporomandibular joint (TMJ) disorders, irritable bowel syndrome, anxiety and depression, morning stiffness, and sometimes memory issues. The currently prevailing theory of causation is that fibromyalgia amplifies painful sensations by affecting how their brain processes pain signals.

However, a new study observing and comparing brain activity in persons with fibromyalgia with that of healthy controls has found evidence that diminished connectivity between pain signal processing and sensorimotor areas of the brain could be contributory to pain regulation deficiency in persons afflicted with fibromyalgia. The study findings were recently published in the peer-reviewed Mary Ann Liebert, Inc. journal Brain Connectivity.

Conducted by PhD student in cognitive neuroscience Pär Flodin at the Karolinska Institutet in Stockholm, Sweden, and research associates, the current study builds on previous fibromyalgia research showing inadequate pain inhibition in the brain’s association with abnormal neuronal activity.

In the Brain Connectivity paper, entitled “Fibromyalgia is Associated with Decreased Connectivity between Pain – and Sensorimotor Brain Areas,” (Brain Connect. 2014 Oct;4(8):587-94. doi: 10.1089/brain.2014.0274) Pär Flodin and coauthors Sofia Martinsen, Monika Löfgren, Indre Bileviciute-Ljungar, Eva Kosek, and Peter Fransson — all of the Department of Clinical Neuroscience at the Karolinska Institutet report a “functional decoupling” pattern detected between pain-processing areas of the brain that receive pain signals in fibromyalgia patients and other parts of the brain, such as the areas that control sensorimotor activity, in the absence of any external pain stimulus compared to how these areas function in healthy patients. This decoupling result in dysfunctional pain perception in persons with fibromyalgia.

The researchers found communication impairment between thalamus and premotor areas, between the right insula and primary sensorimotor areas, and between supramarginal and prefrontal areas in FM patients, and sensitivity of individual subjects o painful pressure was associated with increased connectivity between pain-related regions (for example the insula and thalamus) and midline regions of the default mode network (including posterior cingulate cortex and medial prefrontal cortex) among FM patients compared with controls.

“Fibromyalgia is an understudied condition with an unknown cause that can only be diagnosed by its symptoms,” says Brain Connectivity’s Co-Editor-in-Chief Christopher Pawela, PhD, who is also an Assistant Professor of Plastic Surgery and Biophysics at the Medical College of Wisconsin, in a release. “This study by Flodin et al is an important first step in the understanding of how the brain is involved in the widespread pain perception that is characteristic of the disorder.”

Dr. Pawela’s research focus is on developing develop new treatments and rehabilitation methods for peripheral (sensory) nerve injuries (which can result in lingering fibromyalgia symptoms) through greater understanding of how the brain responds to them. “Peripheral nerve injuries are usually associated with traumatic accidents,” says Dr. Pawela. Even with a successful surgical repair and a motivated patient, outcomes following these injuries can be poor. I use a variety of tools to study brain changes that occur following peripheral nerve injury and repair. These include functional magnetic resonance imaging and electroencephalographic studies of brain activity, as well as microscopic tissue studies.”

The Brain Connectivity paper’s coauthors also note that “Our findings suggest that abnormal connectivity patterns between pain-related regions and the remaining brain during rest reflect an impaired central mechanism of pain modulation in FM. Weaker coupling between pain regions and prefrontal- and sensorimotor areas might indicate a less efficient system level control of pain circuits. Moreover, our results show that multiple, complementary analytical approaches are valuable for obtaining a more comprehensive characterization of deviant resting-state activity.”

Dr. Pawela’s Brain Connectivity Co-Editor-in-Chief is Bharat Biswal, PhD, Chair of Biomedical Engineeringat the New Jersey Institute of Technology. Dr. Bismal is an internationally renowned researcher recognized for his work in mapping the brain’s activity. The National Institutes of Health supports Dr. Biswal’s research. Before coming to NJIT, Dr. Biswal was a professor of radiology at the University of Medicine and Dentistry of New Jersey.

Fifteen years ago as a graduate student working under the mentorship and direction of his advisor, Dr. James S. Hyde at The Medical College of Wisconsin, Dr. Biswal  discovered that the brain, even when resting, contains information about its functional organization. He used fMRI to study how various regions of the brain’ communicate while at rest and not performing any active task. While at the time, Dr. Biswal’s research was questioned, more recently his neuroimaging technique has come to be widely replicated and used with increased recognition that brain activity mapping while the body is at rest is useful in diagnosing various brain disorders.

Sources:
Mary Ann Liebert, Inc., publishers
Brain Connectivity
PubMed.gov

Image Credits:
Brain Connectivity
Medical College of Wisconsin
New Jersey Institute of Technology