In THE SECRET LIFE OF THE BRAIN, a David Grubin Production, it describes that a baby’s brain is a mystery whose secrets scientists are just beginning to unravel. The mystery begins in the womb – only four weeks into gestation the first brain cells, the neurons, are already forming at an astonishing rate: 250,000 every minute. Billions of neurons will forge links with billions of other neurons and eventually there will be trillions and trillions of connections between cells, which greatly exceed the 20, 000 or 30, 000 genes in the human genome. This limited nature of the available genetic information tells that other extrinsic factors play a major role in the development of the nervous system.
The neurons in a baby’s brain receive about one and a half times more synapses than those in an adult’s. According to neuroscience, the first simple synaptic contacts of human brains start during the fifth month of pregnancy. Around the seventh month, extensive synaptic development takes place in all areas of the brain. After birth, synapses continue to form at a very rapid pace, and reach their highest density between six and twelve months old. This makes the scientists to believe that it is as if the brain were designed to form a multitude of synapses in the earliest stages of its development, so that it could adapt to the huge amount of learning that it has to deal with during the first few months of life. But by one year old, the selective elimination of synapses begins to reduce the number of synapses and refine the neuronal connections.