Quick write:How much of our brain do we actually use ?

"It turns out though, that we use virtually every part of the brain, and that [most of] the brain is active almost all the time," Gordon adds. "Let's put it this way: the brain represents three percent of the body's weight and uses 20 percent of the body's energy. 

http://www.scientificamerican.com/article/do-people-only-use-10-percent-of-their-brains/