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ME Research UK, with the financial support of the Irish ME/CFS Association
Along with fatigue and other symptoms, people with ME/CFS describe an increased effort to carry out physical activities, and some individuals have been shown to have reduced strength. Weakness and difficulties with physical tasks could occur through problems with the muscles themselves, or with the motor nervous system, and both have been reported in ME/CFS.
Reduced muscle strength may be due to problems with the nerves that drive these muscles, specifically those nerves in the spinal cord that supply the muscle fibres and control our movements.
Normal function of these nerve cells strongly depends on the neuromodulators serotonin and noradrenaline in the spinal cord – these are chemicals that carries messages between the nerves. Problems with the serotonin system have previously been suggested to contribute to ME/CFS.
The serotonin system has widespread influences across many brain and body functions, and a reduced action of serotonin on the motor nerve cells would make them harder to activate and keep firing. That is, stronger signals from the brain to the spinal nerve cells would be required for the same muscle contractions, and this would be perceived as more effort.
Prof. Taylor and her team plan to record the electrical activity of these nerves during muscle contractions, comparing people with ME/CFS and control subjects.
Signals of muscle activity can be recorded using a grid of electrodes placed on the skin which, when decoded using computer algorithms, can give information about the activity of the motor nerve cells. This technique is called high-density surface electromyography, and Prof. Taylor’s group is one of only three in Australia with the necessary expertise.
The behaviour of motor nerve cells during contractions of the ankle muscles will be compared between people with ME/CFS and healthy control subjects. The researchers postulate that nerve firing rates and the flow of ions into the nerves may be reduced in people with ME/CFS, so they will look specifically at these two parameters.
They will also assess whether any abnormalities are consistent with reduced actions of serotonin, and determine whether changes in nerve cell behaviour are associated with symptoms of ME/CFS.
The findings may help us better understand the muscle problems experienced by people with ME/CFS, and the mechanisms that contribute to these abnormalities. They also have the potential to lead to the development of more effective and targeted treatment strategies.
Prof. Taylor also hopes that this project will help establish the foundations of ME/CFS research in Perth, Australia.