A simulation from the Neitz lab of what colorblindness looks like, with normal color vision on the left and red-green colorblindness on the right. Courtesy of Neitz Laboratory hide caption

itoggle caption Courtesy of Neitz Laboratory

Feces contain digested food residue and a wide variety of microorganisms, mostly bacteria, that are adapted to life in the intestines. The gases the microbes produce could help doctors and scientists track and understand changes related to health. Scimat Scimat/Photo Researchers/Getty Images hide caption

itoggle caption Scimat Scimat/Photo Researchers/Getty Images

By increasing the amount of serotonin in the spinal cord, an experimental drug helps nerve connections work better. Bee Smith/Ocean/Corbis hide caption

itoggle caption Bee Smith/Ocean/Corbis

I'm not trying to lead you astray. It's just that scientists are not skeptical enough about their mouse studies. iStockphoto hide caption

itoggle caption iStockphoto

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

You could do all that brain work. Or you could make it up. iStockphoto.com hide caption

itoggle caption iStockphoto.com

Those are bright bunnies. (The photo shows the two that have the "glowing gene," along with their siblings.) University of Hawaii's John A. Burns School of Medicine hide caption

itoggle caption University of Hawaii's John A. Burns School of Medicine