An area of the canine brain associated with reward responds more strongly to the scents of familiar humans than it does to the scents of other humans, or even to those of familiar dogs.
The journal Behavioural Processes published the results of the first brain-imaging study of dogs responding to biological odors. The research was led by Gregory Berns, director of Emory's Center for Neuropolicy.
A nose for neuroscience: Zen, a golden retriever involved in the study. Photos, above and below, by Helen Berns.