Reduced Hippocampal Function in Fibromyalgia
Research funded by the American Fibromyalgia Syndrome Association (AFSA) brings scientists closer to understanding what is happening in the brains of people with fibromyalgia. Lead investigator Patrick Wood, M.D., found an essential brain substance was significantly lower in the hippocampus region in a group of fibromyalgia patients, compared to age-matched healthy controls.1
The hippocampus plays an essential role in memory and learning, pain regulation, and toning down the body’s response to stress. Given that fibromyalgia patients have cognitive difficulties, severe pain, and a hyperactive stress response, Wood hypothesized that he would find abnormalities in the hippocampus using magnetic resonance spectroscopy (MRS) imaging.
MRS is a technology that enables researchers to measure the concentrations of various brain chemicals or metabolites being produced. One such metabolite, N-acetylaspartate (NAA), is the substance that Wood found to be significantly low in the hippocampus of people with fibromyalgia. NAA is only produced by neurons (not other types of cells), and a reduced level may represent loss of neurons or metabolic dysfunction of the neurons in the hippocampus. Either way, it implies a reduced hippocampal function.
While many abnormalities have been reported in fibromyalgia, only those that can be tied to the symptoms or disease severity are likely to provide treatment insight. Wood found a link that correlates lower NAA values and the person’s level of impairment based on the core features of physical functioning, work status, depression, anxiety, sleep, pain, stiffness, fatigue, and well being. As such, he says his findings lend credence to the idea that a functional or structural defect in the hippocampus contributes to the development of fibromyalgia.
In a previously published study by Wood, he found that fibromyalgia patients did not release dopamine in response to a painful stimulus.2 The healthy control group of subjects released plenty of dopamine and experienced much less pain than the group of fibromyalgia patients. The current finding that the hippocampus is not operating properly offers an explanation because it plays a critical role in controlling the amount of dopamine released by other centers of the brain in response to pain. In addition, it further highlights why medications that increase dopamine in the central nervous system are being evaluated for the treatment of fibromyalgia.
What’s next? A 2007 report by M. Catherine Bushnell, Ph.D., of McGill University in Montreal, showed an accelerated gray matter loss in the hippocampus and many other brain structures involved in pain processing.3 In August of this year, Bushnell was funded by AFSA to replicate these findings using a larger group of subjects and to determine if the results correlate with a variety of measures pertaining to cognitive function and pain.
AFSA is a 501 (c)3, all-volunteer, nonprofit organization dedicated to funding research on the causes and treatments of fibromyalgia. For more information, visit AFSA’s website.
1. Wood PB, et al. J Pain [Epub ahead of print] Sept. 2, 2008.
2. Wood PB, et al. Eur J Neurosci 25:3576-3582, 2007.
3. Kuchinad A, et al. J Neurosci 27:4004-4007, 2007.
Good point. I hadn’t thought about it quite that way.
First and foremost, fibromyalgia IS a real illness. There are specific tests that can be done during a functional MRI that shows the differences in pain responses between an FM patient and a non-FM patient.Have you ever seen a chiropractor for help? Have you been referred to a pain clinic? This would be a way for you to get an updated combination of meds and to help to find other specific management methods that will also be of assistance to you.And when did you last see a rheumatologist? Yes, FM exists, but there are a few other types of arthritis that can mimic some of the effects of FM and that are more easily dealt with.
I get headaches just by carrying a can of coke. I prefer to carry nothing to avoid having pain. I only take pain killers when really unbearable. I don’t like taking medication. I am in pain all the time. I have doctor this week so planning on asking to see rheumatologist. Have you any tips I should ask
Do you know of any Fibromyalgia specialist doctors in the South Western Ontario area? I could really use a good doctor who understands what I am going through.
Also, I have hyperexplexia (an autonomic genetic disorder of the hindbrain) as well as most of the overlapping conditions of FMS. Would you know if these conditions would cause any additional problems. ( I also have PTSD.) Please help!
Accelerated grey matter loss ??!!
Hi Cathie, I had an MRI approximately one year ago and one a year prior to that. The first one noted that I had “areas” of white matter, the one last year showed “a significant amount of white matter given patient’s age” I was 46 at the time. My memory and ability to process things has decreased since then, going to show this article to my Neurologist at next appointment.
I have Fibromyalgia for the past 10 years and the pain is unberable to the point where I had to quit my job.
As an FM patient it is very hard to get alot of things. Was diagnosed more than 13 years ago. never had an MRI they wont give me one, have been to chiropractor, called pain clinics in mass and they offer nothing. rheumatologists I see every 3 to 6 months. nothing feels that way
Does this study provide enough information to determine what medications will relieve the symptoms?