(Taken from Dr. Wilfrid Jänig’s essay on  Autonomic reflexes) Reflexes are functionally defined by an efferent (motor) output system that generates a distinct effector response when activated and by the population of afferent neurons stimulated. Reflexes are fragments of more complex somatomotor behaviors and are used in the laboratory as tools to study experimentally the central organization of neural regulation of movement.

There is no universally accepted definition of reflexes that distinguishes them from voluntary responses to stimuli [1]. The Roman poet Ovid used the word reflex to describe “turning or bringing back.” Substitute “feed” for “bring” and we have the word “feedback.” In engineering, feedback refers to information about a process monitored by sensors and supplied to the controller of that process (see  Feedback control of movement).

In biology, the first attempt at a definition of reflex is attributable to Georgiy Prochaska [2]: a behavior in...