People with Multiple Functional Somatic Symptoms May Had Defunct Pain Modulating Circuits

People with multiple sensitivities and somatic complaints may actually be experiencing untoward pains from what others would not find painful. Recent article finds this may be do to inability to muffle these sensory stimuli due to defunct pain muffling system

Brain Res Bull. 2010 Mar 8. [Epub ahead of print]
Increased sensitivity to supra-threshold painful stimuli in patients with multiple functional somatic symptoms (MFS).
Kuzminskyte R, Kupers R, Videbech P, Gjedde A, Fink P. abstract here

Some years ago was published an article on Multiple Chemical Sensitivities:

Hum Brain Mapp. 2007 Mar;28(3):172-82.
Odor processing in multiple chemical sensitivity.
Hillert L, Musabasic V, Berglund H, Ciumas C, Savic I. abstract here

They showed less activation of odor brain areas and “they showed an odorant-related increase in activation of the anterior cingulate cortex [ACC] and cuneus-precuneus”.

The ACC is the suffer centre where people in chronic pain experience pain with the emotional attachments of dread, fear for the future, helplessness and so on. So when these individuals smell, they suffer for it….

One of the defects in chronic pain is a defect in muffler circuits – any pain is experienced at full volume –

• their brains are oversensitized to the pain (central sensitization),
• the pathways that muffle are shot (NMDA circuit failure), and
• downward acting muffling circuits don’t even turn on (endophin descending inhibitory pathways) – seen in Irritable Bowel Syndrome, migraine and Fibromyalgia

Though pain thresholds were fine in multiple functional somatic symptoms “minor increases in stimulus intensity of supra-threshold painful stimuli may lead to disproportionate increases in pain intensity in MFS patients, suggesting a defunct endogenous pain modulatory system.”

Addendum – DNIC circuits (descending  inhibitory pain circuits) have been found to be impaired in chronic pancreatitis:
1. Clin Gastroenterol Hepatol. 2010 Mar 18. [Epub ahead of print]
Descending Inhibitory Pain Modulation is Impaired in Patients with Chronic Pancreatitis.
Olesen SS, Brock C, Krarup AL, Funch-Jensen P, Arendt-Nielsen L, Wilder-Smith OH, Drewes AM.

abstract here