This article points out the further consequences of pain in Fibromyalgia patients, which are different than in normal people.
Fibromyalgia (FM), of course, is much more than about pain.
Called the “prototypical functional pain syndrome,” people with fibromyalgia often experience problems thinking (fibro-fog), sleep and autonomic nervous system problems, depression and catastrophizing.
The multidimensional aspects of fibromyalgia suggest that more than one part of the brain must be involved.
There’s also more to pain that just pain.
Pain can be accompanied by catastrophizing thoughts and feelings of unpleasantness that are separate from the pain itself.
These “pain plus” symptoms are common in fibromyalgia, and they imply different areas of the brain are affected as well.
The somatosensory link: S1 functional connectivity is altered by sustained pain and associated with clinical/autonomic dysfunction in fibromyalgia. Arthritis & Rheumatology DOI 10.1002/art.39043
A multi-center effort from researchers from Harvard, Michigan, Korea, Colombia, and Germany examined how the pain and other symptoms of FM are linked in the brain.
First they used brain imaging to examine the status of the somatosensory cortex – a part of the brain that processes “somatic” or sensory signals – in relation to other parts of the brain at rest.
Then they wrapped a pressure cuff around their lower leg and inflated it enough to cause the pain receptors in their deep muscle tissues to flare up for six minutes. As they did so they repeated the brain scans.
First they examined how active the connections between the somatosensory regions of the brain that process sensory signals in the leg, back, face, finger and hand were.
Then they examined how active the connections between the somatosensory region and parts of the brain involved in pain catastrophizing and autonomic nervous system functioning were.
As expected the FM patients experienced pain at a much lower cuff pressure than did the healthy controls.
The widespread pain the FM patients came in with suggested that the activity between the different regions of the somatosensory cortex would be increased
Oddly enough, though, reduced activity was found.
The opposite pattern occurs in healthy people.
Being exposed to the same pain stimulus over time, causes the strength of the connections between the different sub-regions of their somatosensory cortex to increase. As that happens their sensitivity to the pain decreases.
The opposite is happening in fibromyalgia.
Insula – A Key Brain Region in Fibromyalgia
Evoking pain with the pressure cuff indicated that a strong communication stream opened between somatosensory cortex and a part of the brain called the insula in the FM patients – but not the healthy controls.
In the healthy controls, however, the pain opened up a connection to a part of the brain called the SPL associated with “attention processing”. That suggested that the healthy controls were noticing the pain more but they weren’t emotionally rocked by it.
Their brains were simply keeping an eye on it.
Just six months ago a similar pattern involving sensory distress in fibromyalgia appeared. Exposing FM patients to light, sound and noise produced a slowed somatosensory activation followed by activation of the insula – and the production of unpleasant sensations.
In 2013 evidence suggested the “gates” in the brainstem that filter out sensory signals are broken in fibromyalgia.
Bansai, interestingly enough, believes the same process is at work in ME/CFS patients, in particular, very severely ill patients who are unable to tolerate stimuli.
It’s at the insula or the connections to the insula that a host of problems kick in worsening everything.
The emotional toll that pain can bring such as catastrophizing, anxiety and worry appear to be associated with the somatosensory cortex- insula connection in FM.
As the pain stimulus continued the connectivity to the right anterior part of the insula continued to build. (This part of the insula is responsible for regulating the autonomic response to external sensory signals).
As that happened, the FM patients experienced further reductions in their ANS stability and increased emotional distress.
That suggested that activation of this one part of the insula is responsible for both the autonomic nervous system dysregulation and emotional distress found in FM.
It’s possible that the emotional hit experienced and the autonomic nervous system dysregulation found in FM are all of a piece; when you get one – you get the other.
That’s simply the consequence of activating this one part of the brain.
Since the connection to the insula was also associated with ever increasing pain as the pain stimulus continued, the insula is also implicated in episodes that increase pain sensitivity in FM.
Interestingly, the connection between the pain catastrophizing and insular activation was not seen during rest.
It only occurred when the pain response was being evoked – and the autonomic nervous system was being triggered.