The ability to recognize faces is so important in humans that the brain appears to have an area solely devoted to the task: the fusiform gyrus. Brain imaging studies consistently find that this region of the temporal lobe becomes active when people look at faces. Skeptics have countered, however, that these studies show only a correlation, but not proof, that activity in this area is essential for face recognition. Now, thanks to the willingness of an intrepid patient, a new study provides the first cause-and-effect evidence that neurons in this area help humans recognize faces -- and only faces, not other body parts or objects.An unusual collaboration between researchers and an epilepsy patient led to the discovery. Ron Blackwell, an engineer in Santa Clara, Calif., came to Stanford University in 2011 seeking better treatment for his epilepsy. He had suffered seizures since he was a teenager, and at age 47, his medication was becoming less effective. Stanford neurologist Josef Parvizi suggested some tests to locate the source of the seizures -- and suggested that it might be possible to eliminate the seizures by surgically destroying a tiny area of brain tissue where they occurred.