There is also concern that the new information is sometimes misinterpreted to mean that if a child has not learned appropriate mental skills by the age of 3, it may be too late to improve brain function. They are able to perform higher-level thinking that is beyond most younger children. Bruce McEwen, a Rockefeller University neuroscientist, said that research on how the brain learns shows that it is capable of building and renewing synaptic connections throughout life. The great explosion of synapses after birth enables the brain to learn how to make itself work from the experiences it encounters. Later, in adulthood and throughout life, the brain constructs new synapses in response to learning.
Synapses are the telephone lines that enable brain cells to communicate.
Trillions are formed during the first two years of life. They are overproduced, it is believed, to guarantee that enough are available to form neural networks for vision, speech, thinking, emotions and other mental capacities. Most synaptic connections appear to be formed randomly, becoming stable only after they have been activated by sensory input from the outside world. Synapses that are not activated by sounds, touch, sight, smell or taste are discarded. Nearly half of the connections eventually are pruned away when they are not incorporated into neural networks.