The relationship between exercise, muscle function and brain health has been known for some time. But how nerve signals affect muscles is not yet fully understood. A figure representing the connection between nerve cells and muscles should now fill this gap.
During exercise, muscles produce brain-boosting hormones and extracellular vesicles called exosomes. These substances play an important role in maintaining balance. This is the system that keeps various body processes stable from the brain, such as temperature regulation. Researchers from the University of Illinois investigated whether there is a link between muscle innervation and the release of these substances. Innervation refers to the presence of nerve fibers that supply a particular tissue or organ with nerve signals. Not all muscles in the body are innervated in the same way. Some muscles have an extensive network of nerve fibers innervating them, while other muscles have fewer nerve fibers or are not innervated at all. Skeletal muscles are responsible for movement and are usually largely innervated by motor neurons that send signals from the central nervous system to the muscles to activate them.
Dysfunction in neural connections
By stimulating nerves with glutamate, researchers found that innervated muscles produced more brain-boosting hormones and extracellular vesicles. This means that the muscles fueled by the neurons produce more substances that promote brain health. During exercise, beneficial hormones, such as irisin, are secreted, and more extracellular vesicles are released that support neural development through a chain reaction. The same nerves that tell muscles to move release those stimulating molecules.
Therefore, nerve connections play an important role in regulating the amount of substances produced by muscles. If nerve connections are disturbed or decreased, for example due to illness or ageing, this can affect how well the muscles and brain work. Maintaining a healthy lifestyle, including regular exercise, can help counter the effects of decreased innervation in older people.
