Corollary discharge circuits in the primate brain.

Movements are necessary to engage the world, but every movement results in sensorimotor ambiguity. Self-movements cause changes to sensory inflow as well as changes in the positions of objects relative to motor effectors (eyes and limbs). Hence the brain needs to monitor self-movements, and one way this is accomplished is by routing copies of movement commands to appropriate structures. These signals, known as corollary discharge (CD), enable compensation for sensory consequences of movement and preemptive updating of spatial representations. Such operations occur with a speed and accuracy that implies a reliance on prediction. Here we review recent CD studies and find that they arrive at a shared conclusion: CD contributes to prediction for the sake of sensorimotor harmony.