What physiological response does the Moro reflex include?

The Moro reflex, also known as the startle reflex, is a primitive reflex observed in infants, usually elicited by a sudden stimulus such as a loss of support or a loud noise. This reflex entails a distinct set of movements where the infant will throw their arms out to the sides and then quickly bring them back in, often resembling a grasping motion, as if they are trying to catch hold of something. This response is crucial as it demonstrates an infant's innate reaction to perceived danger or instability, serving as a protective mechanism.

The throwing of arms and grasping reflects the evolutionary nature of this reflex, as it may have provided a means for early humans to cling to their caregiver in moments of threat. The other options do not accurately capture the complex motor pattern associated with the Moro reflex, which is characterized by the rapid extension and retraction of the arms. Thus, understanding the Moro reflex's movements helps caregivers and healthcare providers assess the neurological development of infants effectively.