In a laboratory hallway at Stanford University, the neurologist and HHMI investigator lays out a small meal for Bear, a fluffy 8-year-old Belgian schipperke. Food is one of Bear's favorite things, along with Mignot himself, and today the combination proves overwhelming. As he tucks into his grub, Bear, the last narcoleptic dog remaining at the university's famous multibreed colony, keels over.

Illustration: Jonathon Rosen