Successive Reflex Combinations

Sometimes reflexes which are antagonistic to one another, when simultaneously aroused, can combine harmoniously in succession. Some of the commonest movements, such as walking, involve a rhythmic succession or alternation of antagonistic reflexes: flexion followed by extension, or the like. It has been shown that, in certain cases, the motor process of extension itself arouses the reflex of flexion, or vice versa, so that an orderly sequence results. The notion of a chain of reflexes, so arranged that the motor phase of one member generates the stimulus to the next member, has frequently been advocated as an explanation of complex acts of a seemingly instinctive nature. Reflexes may be combined into more complex response systems either in this manner or because their respective stimuli are simultaneously provided by the environment.