Which force, external or internal act upon human mind and activate it? Is mind is the prime mover in human?

We have seen motors and pumps. Externally electricity pes thro' and activate it. Internal parts are so designed to fecilitate the flow of air in case of pumps and rotators in case of motors makes it to work. But in the case of human beings, whether any external or internal influence makes him to act and move, think and deliberate? Is mind or the self is the prime mover in him?