Answer:
The corticospinal pathways (bundles of nerve fibers) running from the brain and down the spinal cord are not fully myelinated (sheathed) in newborns and infants.
The Babinski reflex is one of the normal reflexes in infants and in children up to 2 years old. It disappears as the child gets older.
In adults, this reflex is not normal and often indicates a problem with the brain or spinal cord.
Step-by-step explanation:
When the Babinski reflex is present in a child older than 2 years or in an adult, it is often a sign of a central nervous system disorder.