At what point in the human lifespan is the number of neurons at its highest?

The number of neurons in the human brain reaches its peak at birth. During prenatal development, particularly in the later stages of gestation, the brain undergoes extensive neuronal proliferation, resulting in a significant number of neurons being formed. This is a critical period when the developing brain is preparing for the sensory and social experiences that will occur after birth.

While the number of neurons remains relatively high in infancy and early childhood, there are ongoing processes of synaptic pruning that begin shortly after birth and continue into adolescence. These processes involve the elimination of excess neurons and synapses based on experiences and environmental interactions, leading to a decrease in overall neuron count after the initial surge experienced at birth.

Thus, the answer correctly indicates that the maximum number of neurons correlates with the time immediately after birth, setting the foundation for brain development as the child matures.