James in Silver Spring, MD said: Years ago I met a guy who said that science had no answer for the question "How does the brain move the body?" Was he right?
Thank you for the question James. I have been interested in science my whole life -- especially more so as an adult. In all these years I have never heard this. Perhaps at the time that comment was correct. In the past couple decades, a lot of advances have been made in brain science.
Everything the brain does involves an electrical impulse or a chemical reaction. A very simplified explanation for movement starts with an electrical impulse in the brain which travels the spinal cord and routes to the correct nerve(s) in the arm or leg. The jolt of electricity makes the muscles expand or contract as needed to initiate movement. Various chemical reactions aid this process. These movements can be voluntary (picking up a book) or involuntary (breathing). Perhaps the comment concerned the exact mechanisms behind all this -- which are quite complicated, but pretty much understood now.
This underscores why brain injury can be so catastrophic -- which is why we have (and, hopefully, use) seat belts (prevent the brain from hitting the windshield), helmets (to cushion the brain from blows), and neck braces to be used after accidents (to prevent damage to the spinal cord).