A rarely-observed reflex consisting of rhythmic alternating flexion and extension of the limbs, in a pattern such that flexion of the L arm and R leg and extension of the R arm and R leg alternates smoothly with extension of the L arm and L leg and flexion of the R arm and L leg in a pattern reminiscent of four-legged locomotion. This reflex is "released" in situations where the cerebral cortex is functioning abnormally. It is thought that decorticate posturing may represent a "frozen" vestige of this reflex.