Poor sleep, difficulty moving, and injuries from accidental bumps are just a few of the challenges faced by patients with often painful involuntary muscle spasms.
However, an Edith Cowan University (ECU) study of motor neurons in the spine found that two methods can make our spinal cords less “excitable” and could potentially be used.
To move our body, the brain sends messages to the muscles via these motor neurons in the spine which, through “persistent inner currents”, can amplify neural signals so that the brain doesn’t have to work as hard to contract. our muscles.
PhD candidate and principal investigator Ricardo Mesquita said this amplification was vitally important but could also prove problematic; for example, following a spinal cord injury.
These amp powers are great, but sometimes they can be too good. When you want to run fast for the bus, you want that boost; studies show that without it, we wouldn’t be able to produce more than 40% of our usual peak strength.”
Ricardo Mesquita, PhD Candidate and Principal Investigator, Edith Cowan University
“But at the same time, we know that certain clinical conditions are characterized by hyperexcitable spinal motor neurons, with this amplification continuing without any inhibition to stop it.
“It can lead to involuntary muscle spasms which can be painful, cause injury when people accidentally bump into something, restrict movement and wake people up at night.”
Mesquita has identified a pair of seemingly opposing methods that can decrease this neural amplification, which could be further investigated to potentially make life easier for people with involuntary muscle spasms.
The first involves electrical stimulation to specific nerves, which research has shown can reduce amplification in the spinal cord.
“If this method proves clinically effective, we could strategically place a pad and deliver electrical stimulation where it is needed to inhibit the muscle with spasms,” he said.
“These triggers could be automatic, caused by the electrical activity of the muscle or the force of the spasm itself, or it could be manual when people press a button when they have a spasm.”
Try to relax
Mesquita also identified another method that reduces neural amplification: relaxation.
“Amplification is enhanced by special chemicals such as serotonin and norepinephrine that we release when we move,” he said.
“These chemicals should be reduced when we are more relaxed than when we are tensing muscles or stressed.
“Thus, in certain conditions such as brain damage or multiple sclerosis, relaxation therapies might have the potential to decrease this amplification and the severity of spasms.”
Mr Mesquita said current treatment options such as drugs and surgeries are expensive, invasive and often have side effects.
“Electrical stimulation and relaxation techniques could be non-pharmacological alternatives or used in combination with other therapies,” he said.
“Now that we have shown how we can reduce this neural amplification in people without neurological disorders, the next step would be to develop therapeutic protocols to see if they are effective in people who suffer from these symptoms.
“If so, then clinical trials could begin to look at long-term clinical efficacy.”
“Effects of reciprocal inhibition and whole-body relaxation on persistent inward currents estimated by two different methods” was published in the Journal of Physiology.
Mesquita, RNO, et al. (2022) Effects of reciprocal inhibition and whole-body relaxation on persistent inward currents estimated by two different methods. The Journal of Physiology. doi.org/10.1113/JP282765
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