Abstract
Every animal must learn how to use its limbs within the developmental context of an ever-changing body. Typically, investigations of sensorimotor development focus on waking movements. Here I consider another class of behavior: Twitching movements that occur exclusively during active (REM) sleep. Twitches are particularly abundant in early infancy when critical sensorimotor networks are established. In light of behavioral, electrophysiological, neurophysiological, and computational investigations of this unique behavior, twitches may prove critical for the development and maintenance of the sensorimotor system, as well as its repair after injury or disease.