Pupil can constrict without any input from brain
You've seen it on television: A doctor shines a bright light into an unconscious patient's eye to check for brain death. If the pupil constricts, the brain is OK, because in mammals, the brain controls the pupil. Or does it? Now, researchers at Johns Hopkins have discovered that in most mammals, in fact in most vertebrates, the pupil can constrict without any input from the brain.