Disruption of Neural Networks May Impact Fibromyalgia Pain

New research finds that hyperreactive brain networks could play a part in the hypersensitivity of fibromyalgia.

The study suggests the human nervous system has common characteristics to an electric power grid whereby a small disruption in one area of the network can cause the entire network to go awry.

Investigators from the University of Michigan and Pohang University of Science and Technology in South Korea discovered that patients with fibromyalgia have brain networks primed for rapid, global responses to minor changes.

This abnormal hypersensitivity, called explosive synchronization (ES), is a finding that has been observed in other network phenomena across nature. The discovery of ES in the brains of people with fibromyalgia helps to explain why widespread, chronic pain is often experienced.

The paper, published in Scientific Reports, is only the second study to detail ES in human brain data.

“For the first time, this research shows that the hypersensitivity experienced by chronic pain patients may result from hypersensitive brain networks,” said co-senior author Richard Harris, Ph.D., associate professor of anesthesiology at Michigan Medicine.

“The subjects had conditions similar to other networks that undergo explosive synchronization.”

In ES, a small stimulus can lead to a dramatic synchronized reaction in the network, as can happen with a power grid failure (that rapidly turns things off) or a seizure (that rapidly turns things on).

This phenomenon was, until recently, studied in physics rather than medicine. Researchers say it’s a promising avenue to explore in the continued quest to determine how a person develops fibromyalgia.

“As opposed to the normal process of gradually linking up different centers in the brain after a stimulus, chronic pain patients have conditions that predispose them to linking up in an abrupt, explosive manner,” says first author UnCheol Lee, Ph.D., a physicist and assistant professor of anesthesiology at Michigan Medicine.┬áThese conditions are similar to other networks that undergo ES, including power grids, Lee says.

The researchers recorded electrical activity in the brains of 10 female participants with fibromyalgia. Baseline EEG results showed hypersensitive and unstable brain networks, Harris says.

Importantly, there was a strong correlation between the degree of ES conditions and the self-reported intensity of chronic pain reported by the patients at the time of EEG testing.

Lee’s research team and collaborators in South Korea then used computer models of brain activity to compare stimulus responses of fibromyalgia patients to the normal condition.

As expected, the fibromyalgia model was more sensitive to electrical stimulation than the model without ES characteristics, Harris said.

“We again see the chronic pain brain is electrically unstable and sensitive,” he said.

Harris noted this type of modeling could help guide future treatments for fibromyalgia. Since ES can be modeled essentially outside of the brain or in a computer, researchers can exhaustively test for influential regions that transform a hypersensitive network into a more stable one. These regions could then be targeted in living humans using noninvasive brain modulation therapies.

George Mashour, M.D., Ph.D., co-senior author and professor of anesthesiology at Michigan Medicine, said, “This study represents an exciting collaboration of physicists, neuroscientists and anesthesiologists. The network-based approach, which can combine individual patient brain data and computer simulation, heralds the possibility of a personalized approach to chronic pain treatment.”

Source: University of Michigan