Aschner reflex

In human physiology, many reflex reactions are known, thanks to which our body instantly reacts to external and internal stimuli. Each of us has experienced similar reactions at least once, for example, flinching at a sudden sound or feeling a palpitation when someone accidentally steps on our feet.

One of these reflex reactions is the ocular-heart reaction (Aschner reflex). This is the name of the physiological process of contraction of the heart under the influence of a light stimulus. It was first described in the 18th century. The discovery of this phenomenon is based on the principle of unconditioned reflexes, which consists in the formation of a temporary complex and persistent muscle response to a certain type of stimulus.

In 1906, the American scientist William Ashner, while studying the reflex response of muscles to visual stimuli, noticed the following: when a bright object is quickly moved from one place to another, contractile tension occurs in the muscles.

The reaction appears seven years after the birth of the baby. Its duration is about 30 seconds. After this, muscle tension subsides, but persists for a couple of seconds. A significant release of the hormone adrenaline provokes the manifestation of a somatic reflex, including motor activity of the limbs, nose, eyelids, cheeks, and larynx. In addition, the strength of the pharyngeal reflex increases. After a person’s gaze focuses on a bright object, the reflexogenic zone crosses the course of the oculocardiac nerve. For the last fractions of seconds the child is in a state of fainting.

The mechanism for the formation of this reflex response is easily explained: external stimuli stimulate the nerves of the eyeball. Blood pressure and heart rate are regulated.