What reflex is characterized by the upward stroking of the foot sole causing the toes to extend outward in infants?

The response referred to here is the Babinski sign, which is a reflex observed in infants when the sole of the foot is stroked upwards from the heel to the toes. This action typically results in the toes extending outward and the big toe curling upwards. This reflex is considered a normal developmental milestone in infants and often disappears as the nervous system matures, usually after the age of two to three years. The presence of the Babinski sign in adults, however, may indicate neurological issues, as it is not a normal response in that age group.

In contrast, the rooting reflex is a behavior where an infant turns their head and opens their mouth in response to a stimulus on their cheek, which is important for feeding. The grasp reflex describes an infant's tendency to close their hand tightly around an object placed in their palm. Finally, the startle reflex, or Moro reflex, involves an infant flinging their arms outward and then retracting them as a response to sudden movements or loud noises. Each of these reflexes serves different developmental purposes and is recognized as an important aspect of infant behavior and neurological development.