Over the course of two months, researchers trained macaque monkeys to lift more and more weight, until they were able to do the equivalent of a one-armed pull-up. When the researchers stimulated a bundle of nerves in the spinal cord known as the reticulospinal tract (RST), they saw increases in the resulting neuronal electrical signals in the monkeys’ arm muscles as training progressed, while they did not see the same consistent upward trend in the muscles’ responses to stimulation of the corticospinal tract (CST). The results suggest that RST connectivity may play a critical role in muscle strengthening.
Published in The Scientist magazine, October 2020. Writing by Jef Akst.