The Centre on the Developing Child at Harvard University is a world leader in the drive to bring science-based research and innovation into our understanding of child development. It provides an extensive range of high quality and informative resources regarding brain development & child development. This is a highly respected, internationally regarded and trusted site. Highly recommended.
A few samples of information from this site
Building Brain circuits
Building babies Brains through Play
Serve and Return Shapes brain circuitry