President Obama has pledged millions of dollars to fuel research into understanding the workings of the human brain. Zephyr/Science Source hide caption

itoggle caption Zephyr/Science Source

Submitting a DNA sample to networking company 23andMe entails spitting a saliva sample into a plastic vial. 23andMe hide caption

itoggle caption 23andMe

In a study, patients with Parkinson's disease, a progressive nervous-system disorder, had fewer falls after taking up Tai Chi. iStockphoto hide caption

itoggle caption iStockphoto