Eli5: How can we move almost any muscle the time we want? How does the brain knows it’s that specific muscle that you want to move?

Question

Like, I can be there just sitting and think. “Now I’m gonna move my middle finger”, and just do it, no reason at all. How does the brain know what muscle is each, how does a signal is determined to make you move the finger you want? Does the brain have a “map” or something of every muscle in your body?

In: Biology

Answer 1

I read about something like this in my psychology textbook the other day, so I’m not an expert but this is what I found: there are 2 pathway systems when it comes to sensing touch: the “what” system, and the “where” system. The “what” system is a pathway in touch that provides information about the properties of surfaces/objects. The “where” system is a pathway that provides info about a location in external space that is being touched, or a location on the body that is being stimulated. Separate from that are things in your brain called “basal ganglia” which direct intentional movements. Within the basal ganglia is something called the “striatum” which controls posture and movement. So it seems like these structures do make a sort of “map” in your brain of where all of your body parts are and how they are positioned. So while my answer isn’t an entire answer to your question, that’s all I know as a wee college student.