The human brain looks like a big, pinkish-gray, wrinkly walnut. There are so many folds in it that, if it could be unfolded, it could be a small tablecloth. Pinkish-gray might not match your decor, but it would be about the right size! This "tablecloth" is made up of the cerebral cortex and is the wrinkly outside layer of your brain. All those folds are responsible for abstract thought, language, and memory. Scientists believe the wrinkles exist as a way to increase the surface area of the cortex, allowing for increased brainpower in a smaller space. In this week’s Today I Learned, neuroscientist and National Geographic Emerging Explorer Steve Ramirez shares some of his smarts on how your cortex is different from your pet hamster’s.