Canine Cognition & Comparative fMRI
@Emory University
Training for unsedated, unrestrained fMRI
Training for functional Magnetic Resonance Imaging (fMRI) studies involves positive reinforcement (praise or treats) in order to get the dog to lie still for an fMRI scan sequence. This involves an extended down-stay, placing their head in a chin rest, wearing ear plugs or mutt muffs, and holding that position until they are given the O.K to leave. Dogs receive training to desensitize them to the sounds of an fMRI scan as well. Of course, if they decide to leave on their own during a scan, that's fine too.
Testing
An MRI takes an image of the dog's brain both at the structural and functional level. This involves the dog lying in the center of essentially a giant magnet, where energy from the copper coils wrapped around the magnet alters the spins of the atoms within the brain. We measure the energy produced for the spin to return to its normal rotation. This is how MRI can be used to create a brain image. In functional MRI, the subject is engaged in a type of task that requires a change in the level of activity within the neurons (cells) of the brain. These neurons require increased oxygenated blood when the level of neuronal activity increases. With fMRI, we can measure the changes that occur in blood flow as a result of neuronal activity. This is safe for the dogs and for humans. The uncomfortable part is the loud noise and tight enclosure, which is why the dogs wear earplugs and go through extensive training to stay still so that the brain images remain in focus.
Results
One area of interest is the caudate nucleus, which is an area in the brain related to reward/ motivation processing in both humans and non-humans. Dogs show individual differences in caudate activation depending on if their owner is giving them praise, or if they are receiving food, when they smell their owner compared to the smell of a stranger, etc..
Dogs also have an area in their brain related to face processing, similar to humans.
Dogs also have extremely large olfactory cortex when compared to humans. My interest in particular is the role in olfaction in canine cognitive processes. I am also interested in how olfaction can facilitate cross-modal training, such as matching a scent to a person or an object.
Above: an example of comparative brain anatomy. The left is a top-down view of a dog's brain, the right is a top down view of a human. The white arrows point to the caudate nucleus of the dog and of the human. This area of the brain is linked to reward processing in both species.
For a short video of the canine fMRI research at Emory, check out this video featuring some of the dogs from the lab during their first few MRI scans.