Glabellar reflex
The glabellar reflex, also known as the "glabellar tap sign", is a primitive reflex elicited by repetitive tapping on the forehead. Subjects blink in response to the first several taps. If the blinking persists, this is known as Myerson's sign, and is abnormal and a sign of frontal release; it is often seen in people who have Parkinson's disease.
The afferent sensory signals are transmitted by the trigeminal nerve to the brain stem; the efferent signals go to the orbicularis oculi muscle via the facial nerve, causing the muscle to reflexively contract, yielding blinking.
