

90% of brain development completes by the age of 5 4.By age 3, the synaptic connections have grown to 1000 trillion.Infant’s neurons are connected by only roughly 50 trillion new neural connections, called synapses, whereas an adult brain has about 500 trillion of them 3.Although a newborn has about the same number of neurons as an adult, it has only 25% of the adult size.A baby’s brain at birth has roughly 86 billion brain cells (neurons) 1, almost all the neurons the human brain will ever have 2.This network of synaptic connections will ultimately determine brain function and the development of behavior. New environments, life experiences, caretakers, and relationships can all affect the way complex brain circuits are wired.


The young developing brain literally changes shape and size in response to everything encountered in the early years. Early childhood is a time of tremendous brain development.
