Where does most neural activity occur in the infant brain?

The cortex is the area of the brain that is most involved in neural activity during infancy, as it plays a crucial role in higher brain functions such as sensory perception, motor control, conscious thought, and memory processing. During the early stages of development, the cortex undergoes significant maturation and plasticity, allowing for the establishment of neural connections that are essential for cognitive and physical growth. This period of rapid development is vital for laying the groundwork for future learning and development.

While the cerebellum, brainstem, and hippocampus have important functions, their roles during infancy do not match the level of neural activity taking place in the cortex. The cerebellum is primarily involved in motor control and coordination but does not engage in higher cognitive functions to the extent the cortex does. The brainstem is responsible for basic life functions such as heartbeat and breathing, and though essential, it operates largely at an unconscious level. The hippocampus is associated with memory formation and spatial navigation, but it is not as active in the early months of life as the cortex. Thus, the cortex's vital role in sensory processing and cognitive function makes it the region with the most significant neural activity during infancy.