Restoring Muscles by Stimulating the Brain

Elisa Kallioniemi slides a circular disk over her head, stops above her right ear and clicks. Her left hand jumps. She moves it a couple of inches back, clicks again, and is suddenly speechless, mid-sentence. With a single pulse of electromagnetic energy, her device can activate or inhibit the brain’s major command centers.

What she is now trying to determine is whether multiple pulses in the motor cortex can produce longer-term therapeutic results by retraining neural circuits. Her first focus is people who have lost some control of their limbs following a stroke.

“We know from psychiatry that by activating neurons with transcranial magnetic stimulation (TMS) we can change the way the brain functions,” said Kallioniemi, an assistant professor of biomedical engineering at New Jersey Institute of Technology. The therapy has FDA approval for clinical treatment of depression, obsessive-compulsive disorder, smoking cessation and migraines with auras.

“But there are no FDA-approved TMS therapies at this point for motor rehabilitation,” she added. “People need to relearn motor skills such as grasping after a stroke, for example, which changes brain structure and function.”

Funded by the New Jersey Alliance for Clinical and Translational Science, she will first test healthy people to get a better understanding of the neurophysiological effects of TMS. She’ll measure their speed and accuracy in typing a series of numbers and record changes in the peripheral muscles with electromyography to see how effectively TMS activates the motor system.

For some maladies, researchers in the field hope to develop a non-invasive, more precise alternative to drugs, for example, which target neurotransmitters throughout the brain and cause side effects. By contrast, the only sensation electromagnetic waves cause is a slight contraction in the muscles of the scalp.

One goal is to reduce opioid use for chronic pain. Another is to enable surgeons to map the brain before operating on a tumor to determine which muscles they could potentially affect with its removal.

“But we don’t fully understand how TMS works, so we’re developing different protocols to measure impacts on the motor cortex. Mine is to administer pulses in pairs with particular timing,” she said. As in psychotherapy, the aim is to figure out the correct parameters needed to restore some movement and function and how often the procedure needs to be repeated for maintenance.

To advance fundamental research, Kallioniemi’s lab is part of a global consortium studying the two neurophysiological systems in the brain: one that excites neurons into action and another that inhibits it.

“There is an interplay between these two systems at all times,” she noted. “With brain disorders, there is an imbalance by which the systems may be moving too quickly or too slowly. The impacts are not only visible, such as the inability to move a hand properly, but also operate at a deeper level affecting cognition and memory, for example.”

Together, they’re creating a large dataset to determine the reliability of biomarkers in both systems. Down the road, it could be used to identify neurophysiological features for brain disorders and other conditions and to see how people respond to treatment over their lifespan. Beginning with the motor cortex, the researchers plan to make all of their data, data analysis and testing protocols open to the public.

As Kallioniemi explained, “We want to know if we’re getting the same results.”