Locomotor oscillations with asymmetric drive to CPG half-centers. (A1) and (A2) repeat the diagram shown in Figure 4F, with vertical dash-dot line indicating drives used in simulations shown in (B1) and (B2), respectively. (B1) An example of a flexion-dominated “fictive locomotion” pattern generated by the CPG (with no afferent feedback) with drive to RG-E set to 1.4, and drive to RG-F set to 1.8 (see in (A1)). (B2) An example of an extensor-dominated “fictive locomotion” pattern generated by the CPG with drive to RG-E set to 1.4, and drive to RG-F set to 1.2 (see in (A2)). (C1) and (C2) The extensor-dominated pattern of “normal locomotion” with the same values of drives as in (B1) and (B2), respectively, with afferent feedback intact. Note that feedback prolongs the extensor phase in (C1) and shortens it in (C2).