March 18, 2014
Scent Of A Dog’s Owner Lingers In The Brain
Lee Rannals for redOrbit.com - Your Universe OnlineGregory Berns, director of Emory University’s Center for Neuropolicy, performed the first brain-imaging study of dogs responding to biological odors. The study involved 12 dogs of various breeds that had all undergone training to hold perfectly still while undergoing an fMRI scan.
While the dogs were being scanned, researchers presented the subjects with five different scents that had been collected on sterile gauze pads that morning and sealed in Mylar envelopes. The scent samples came from the subject itself, a dog the subject had never met, a dog that lived in the subject’s household, a human the dog had never met, and a human that lived in the subject’s household.
The team found that all five scents elicited a similar response in parts of the dogs’ brains involved in detecting smells. However, the caudate responses were significantly stronger for the scents of familiar humans, followed by that of familiar dogs.
“The stronger caudate activation suggested that not only did the dogs discriminate the familiar human scent from the others, they had a positive association with it,” Berns said in a statement. “While we might expect that dogs should be highly tuned to the smell of other dogs, it seems that the ‘reward response’ is reserved for their humans. Whether this is based on food, play, innate genetic predisposition or something else remains an area for future investigation.”
The researchers also found that dogs in the study that had received training as service or therapy dogs showed greater caudate activation for the scent of a familiar human compared with the other dogs.
“It’s one thing when you come home and your dog sees you and jumps on you and licks you and knows that good things are about to happen,” Berns says. “In our experiment, however, the scent donors were not physically present. That means the canine brain responses were being triggered by something distant in space and time. It shows that dogs’ brains have these mental representations of us that persist when we’re not there.”
He said the team is planning to do future research to determine whether they can use brain-imaging techniques to better identify dogs that are optimal to serve as companion animals for the disabled.
“In addition to serving as companion animals for wounded veterans, dogs play many important roles in military operations,” Berns says. “By understanding how dogs’ brains work, we hope to find better methods to select and train them for these roles.”