The total number of synapses begins to stabilize. Synaptic pruning continues through adolescence, but not as fast as before. In the visual cortex, pruning continues until about 6 years of age. During this time, about 50 percent of the extra synapses are eliminated. Synaptic pruning happens very quickly between ages 2 and 10. Ages 2 to 10 yearsĭuring the second year of life, the number of synapses drops dramatically. This part of the brain is used for a variety of complex behaviors, including planning and personality. In the prefrontal cortex, peak levels of synapses occur sometime during the first year of life. In the visual cortex of the brain (the part responsible for vision), synapse production hits its peak at about 8 months of age. By age 2 or 3, an infant has about 15,000 synapses per neuron. New neurons and synapses are formed by the brain at an extremely high rate during this time.ĭuring the first year of life, the number of synapses in the brain of an infant grows more than tenfold. By the seventh month of a pregnancy, the fetus starts to emit its own brain waves. Early embryonic stage to 2 yearsīrain development in the embryo starts just a few weeks after conception. Some synaptic pruning begins very early in development, but the most rapid pruning happens between roughly age 2 and 16. The timing of synaptic pruning varies by brain region.

But if a child receives little stimulation the brain will keep fewer of those connections. Constant stimulation causes synapses to grow and become permanent. In other words, whether or not a synapse is pruned is influenced by the experiences a developing child has with the world around them. The process of removing the irrelevant synapses during this time is referred to as synaptic pruning.Įarly synaptic pruning is mostly influenced by our genes. In other words, the process follows the “use it or lose it” principle: Synapses that are more active are strengthened, and synapses that are less active are weakened and ultimately pruned. This depends on how often the synapse is used. Once the brain forms a synapse, it can either be strengthened or weakened. But then shortly after this period of synaptic growth, the brain starts to remove synapses that it no longer needs. At about 2 to 3 years of age, the number of synapses hits a peak level. This rapid period of synaptogenesis plays a vital role in learning, memory formation, and adaptation early in life. There is an explosion of synapse formation between neurons during early brain development. During infancy, the brain experiences a large amount of growth.

Brain neuron connections