“Step back a half-billion years ago, to when the first nerve cells developed. The original need for a nervous system was to coordinate movement, so an organism could go find food, instead of waiting for the food to come to. Jellyfish and sea anemone, the first animals to create nerve cells, had a tremendous advantage over the sponges that waited brainlessly for dinner to arrive. After millions of generations of experimentation, nervous systems evolved some amazing ways of going out to eat. But behind all the myriad forms of life today, the primary directive remains – Movement. In fact, a diminished ability to move is a good measure of aging.”