In a biological motor system, the drive signal for each muscle is a function of many variables. These include feedback from sensors that measure position, velocity,
and acceleration of the limb; stretch in muscles; tension in tendons; and tactile sensations from various points on the skin. Feedback also includes information from the
eyes via the superior colliculus and visual cortex about the positions of the hands and feet relative to their intended targets. Drive signals to the muscles also depend on higher level ideas, plans, intentions, motives,and urges. These may be specified by variables that
identify the name of the task to be performed and
specify the goals that are desired, the procedures and knowledge required to achieve those goals,and the priorities that have been assigned to achieving those goals.