Among other things, my search came up with a goodreads page with over 250 quotations tagged Brain.
Here are a few I liked:
I am a brain, Watson. The rest of me is a mere appendix.
~Arthur Conan Doyle, The Adventure of the Mazarin Stone
How ghastly for her, people actually thinking, with their brains, and right next door. Oh, the travesty of it all.
~Gail Carriger, Soulless
Every man can, if he so desires, become the sculptor of his own brain.
~Santiago Ramón y Cajal
Biology gives you a brain. Life turns it into a mind.
~Jeffrey Eugenides, Middlesex
See which ones appeal to you. Here’s the complete list. The wonderful thing about it is that each quote is given with author name and link to the respective book as well as author page.