Everything we do alters our brain not only on the molecular and cellular level, but also leads to the rewiring of brain and sometimes significant morphological changes inside the organ. When we learn, walk around a new place, meet somebody new or achieve new experience, our brain and its connections change. Some brain areas become larger, some others shrink in size, some become more active, while others get inactivated. The process is known to be mediated by the production and release of a protein called NGF (nerve growth factor) which creates more connections between neurons.