A neuroscientist’s neon pink arm cast led him and fellow researchers at Washington University School of Medicine in St. Louis to discover previously undetected neuronal pulses in the human brain that activate after an immobilizing illness or injury.
The pulses appeared on MRI scans used to measure brain activity of the neuroscientist and, later, two additional adults whose arms were in casts. The researchers compared those MRI images with scans of the scientists before and after their arms were put in casts.
The scans showed that the brain’s main circuits responsible for movement in specific areas of the body disconnected within 48 hours of a person wearing a cast that encumbered movement in such an area. Also during this time, “disuse pulses” emerged to maintain neural activity and allow the main motor circuits to reactivate if and when mobility was restored through physical therapy.
The findings, published online June 16 in Neuron, offer clues to how the brain’s billions of neurons — cells that transmit nerve impulses — can rewire and restore pathways after injury or illness. Understanding just what is behind this resiliency may lead to new therapies for people with broken limbs or recovering from strokes or other immobilizing conditions.
“Many scenarios exist in neurology in which a person doesn’t use an arm or a leg and, consequently, related brain circuits for an extended period of time,” said senior author Nico Dosenbach, MD, PhD, an assistant professor of neurology. “In offering the best care to patients, it’s important to understand specifically what changes occur in brain function. Accurate understanding and mapping of these circuits may lead to advancements in treating patients who have lost use of their limbs.”