One path is to the brainstem which controls eye movements, another path is to the thalamus, which send information to different areas of the cerebral cortex. Visual experiences are essential for the proper development of the brain circuits underlying vision. Hubel and Wiesel were the first to experiment with depriving kittens and monkeys of normal visual experiences during early development. Their work won the Nobel Prize. The critical period for wiring human vision is the first two years, with some plasticity through age nine.
Visual experiences create the neuronal connections which wires the brain appropriately.
At birth a baby has been hearing for about 12 weeks. Babies who hear The Cat in the Hat repeatedly before birth, sucked more when they heard it after birth, an indication they remembered the sounds. Much of the auditory processing is done in the brainstem and thalamus, yet conscious hearing is in the temporal lobes. These auditory pathways continue to be myelinated for at least two years, but the cortical processing systems are not fully mature until the midteen years. A baby's experiences with language and music create a brain attuned to its environment.