I have read that average IQ is about 100, corresponding to about 13% usage of brain's neurons. Albert Einstein is said to have IQ above 160 and used about 21% of his brain's neurons. 100/13=7.69; 7.69*21=161.54; sounds about right so I guess I am using about 126/7.69=16.38% of my brain's neurons, that's less than a quarter of my brain's neurons is put to use. But, by God's grace, whatever percentage, let's hope it's used for His glory and for the good of mankind. We do not want Adolf Hitler to use even a quarter of his brain's neurons, do we?