Final answer:
A single motor cortex neuron can activate several muscles, as part of a motor unit that controls muscle fibers for precise to powerful movements, a concept known as recruitment.
Step-by-step explanation:
The answer to the student's question is true: a single motor cortex neuron can indeed activate several different muscles. The key concept here is the motor unit, which comprises a motor neuron and all of the muscle fibers it innervates. The size of a motor unit can vary greatly depending on the muscle's function. For instance, large muscles like the quadriceps may have motor units with up to 1000 muscle fibers, which is suitable for gross movements that don't require fine precision.
In contrast, muscles needing precise control, such as the extraocular muscles, have motor units with as few as 10 fibers. This structural arrangement allows the nervous system to exercise a wide range of control, enabling both delicate and powerful movements through a process called recruitment. As more motor units are activated, the muscle contraction strengthens. Therefore, the organization of the motor cortex aligns with the body's muscle organization to facilitate precise and varied muscle contractions.