Abstract
Neural networks in the hindbrain and spinal cord generate the simple patterns of motor activity that are necessary for breathing and locomotion. These networks function autonomously, producing simple yet flexible rhythmic motor behaviours that are highly responsive to sensory inputs and central control. This review outlines recent advances in our understanding of the genetic programmes controlling the assembly and functioning of circuits in the hindbrain and spinal cord that are responsible for respiration and locomotion. In addition, we highlight the influence that target-derived retrograde signaling and experience-dependent mechanisms have on establishing connectivity, particularly with respect to sensory afferent innervation of the spinal cord.