What is the startle reflex commonly known as?

The startle reflex is commonly known as the Moro reflex. This reflex is observed in newborns and is characterized by an involuntary response to a sudden loss of support or a loud sound. When the infant perceives a sensation of falling or experiences a startling stimulus, they typically extend their arms and legs outwards, followed by a quick return to the body, often accompanied by crying. This reflex is a primitive response believed to be a protective mechanism, helping infants react to potential threats in their environment.

The Moro reflex usually appears at birth and is fully developed by about 28 weeks gestation, then typically disappears by 4 to 6 months of age as the infant's nervous system matures. Understanding this reflex is essential for healthcare providers to assess normal neurodevelopmental milestones in newborns. In contrast, the other reflexes listed, like the rooting reflex (which allows infants to turn their head towards a stimulus and make sucking motions when their cheek is stroked), the grasp reflex (where infants automatically grasp anything placed in their palm), and the Babinski reflex (in which the toes splay outward when the sole of the foot is stimulated), serve different functions and are associated with other developmental stages.