I highly recommend this book! (available in Sydney public libraries.)
The discovery that our thoughts change the structure and function of our brains even into old age is the most important breakthrough in neuroscience for 400 years.
In this revolutionary look at the brain, Norman Doidge introduces the brilliant scientists championing this new science of neuroplasticity, highlights principles we can all use (see below for the tai chi one!) as well as a collection of case histories - stroke patients cured, a woman with half a brain that rewired itself to work as a whole, learning and emotional disorders overcome, IQs raised and aging brains rejuvenated.
Chapter Rejuvenation, pg 255: "Exercise stimulates your sensory and motor cortices and maintains your brain's balance system. These functions begin to deteriorate as we age, making us prone to falling and becoming housebound. Nothing speeds brain atrophy more than being immobilized in the same environment; the monotony undermines our dopamine and attention systems crucial to maintaining brain plasticity. A cognitive rich physical activity such as learning new dances will probably help ward off balance problems and have the added benefit of being social, which also preserves brain health. Tai Chi requires intense concentration on motor movements and stimulates the brain's balance system. It also has a meditative aspects, which has been proved very effective in lowering stress and so is likely to preserve memory and the hippocampal neurons."
I know when I'm building new neuron pathways as my head feels ready to explode or just hurts and I want to shut down and fall asleep. Sleep allows the brain to develop which explains why children and adolescents need so much sleep as their brains mature. How do you react?