"Your child was born with about 100 billion brain cells.  That's amazing enough, but what's happening now that he's a toddler is almost more so.  Each of those brain cells is sending out and receiving electrical signals, creating connections among brain cells that, through repetition, turn into networks. The networks (often called wiring or circuitry) allow him to think and learn.  By his third birthday your toddler's brain will have formed about 1,000 trillion connections." - Quote on how to raise an imaginative child