Modern brain imaging is revolutionizing the study of brain function in health and disease. However, few realize that its origins began in the nineteenth century with Dr. Angelo Mosso's pioneering experiments.

A foremost Italian physiologist and scientist, Angelo Mosso studied several patients brought to him with head injuries that exposed their live brains to direct, long-term observation. He took advantage of these rare opportunities to document, for the first time, changes in cerebral blood flow in response to different stimuli, behaviors, and emotions, the very same changes that are...