Medically reviewed by Brigid Dwyer, MD Key Takeaways Clonus causes involuntary, rhythmic muscle contractions when a muscle is stretched.It is often observed in conditions like multiple sclerosis, ...

A skeletal muscle isn’t much use without a signal telling it to move. In vertebrates, this signaling happens at the neuromus-cular junction (NMJ), a synaptic connection between motor neurons and ...

MIT scientists find that motor neuron growth increased significantly over 5 days in response to biochemical (left) and mechanical (right) signals related to exercise. The green ball represents cluster ...