A closed-loop system involves feedback, whereas an open-loop does not. In the open-loop system, because feedback is not used in the control of the ongoing movement, the instructions contain all the information necessary for the effectors to carry out the planned movement. Although feedback is produced and available, it is not used to control the ongoing movement. In the closed-loop systems, the movement instructions are different. The control center issues initial instructions that is sufficient only to initiate the movement. The actual execution and completion of the movement depend on feedback information that reached the control center.