Figure 2: Schematic diagram depicting the role of the efference copy in the motor control system. Information from current state variables (e.g. joint position sense) is used to create a prediction of the sensory consequences of any motor command. This prediction, or efference copy, is compared (comparator) with the actual sensory consequences of that new activity. When a discrepancy is noted this information is fed back to the motor command system to update the state variables and thereby inform future efference copies [4].