A system and method for quantitatively assessing the changes in control of asymmetric locomotor behavior of an animal comprising analyzing the phase modulation in response to imposed asymmetric stepping tasks for quantitatively assessing changes in control of asymmetric locomotor behavior. A walkway gait device is provided comprising an elevated grid having at least one platform having a face and at least two or more pegs located in front or back of said platform, wherein each peg has a pressure sensor or switch in communication with a detection unit for capturing the pressure detected by one or more of the pressure sensors or switches. Preferably, the grid of the walkway gait device has at least three platforms to form a closed path loop.