As many will know, we have been running Sport Scent Dog Discrimination classes at the Academy for some time now. In researching for presentation of this class I ran across a recent study published in a scientific journal presenting some insight to the extent that scent plays in the life of our canine family members.
The study was designed to identify any differences in response to human vs canine scents. But what I found more interesting than the result, was the whole experimental design and training involved to carry it out.
According to the study there is a well known area of the brain responsible for prediction of a reward. The study group used a functional MRI to examine the brain’s response to various scents. Now I have never personally been in an MRI machine, but from what I have seen on TV and heard anecdotally, they are loud, Closter phobic and scary. And that’s for humans! The dogs had to be trained to remain motionless with there head on a chin rest inside the machine for 30 minutes at a time while the scents were presented!
Quoting directly from the report;
“The program was based on acclimatization to the MRI scanner noise, tight scanner enclosure, scanner steps, and operating vibrations and the shaping and ultimate chaining of several requisite behaviors. To do this, we constructed two replica MRIs, each of which consisted of a tube of approximately the same dimensions as the inner bore of the actual Siemens MRI, a patient table, portable steps, and multiple simulated receiver coils that adhered closely to the dimensions of a human neck coil. We also constructed a proprietary chin rest that facilitated comfort and proper positioning for the animals and that adapted the apparatus for the uniqueness of the canine anatomy. Once the animals became confident and competent regarding all the preparatory steps – proven by completing a simulated MRI in the replica apparatus – we then performed live scans in the actual MRI.”…” They were all highly proficient remaining in the chin rest, wearing ear muffs, while hearing the scanner sounds.”
And further on:
“Training for the smell experiment consisted of biweekly instruction at our training facility and practice at home with the mock head coil and chin rest. Because the dogs were already proficient in the basic behavior of placing the head in the chin rest and remaining motionless, the added training was aimed at acclimating the dogs to the presentation of a cotton swab in front of the nose. Using 6-in. sterile cotton swabs, handlers moved the swab to within a centimeter of the dog's nose. In the initial stage of training, dogs were rewarded quickly for not moving either toward or away from the swab. This was achieved through either clicker or praise and followed by a food reward. Once dogs demonstrated proficiency at not reacting to the swab, we replaced the clicker and praise with the hand signal learned in the original experiment. The hand signal thus functioned as a “visual clicker indicating correct behavior and imminent reward (because clickers cannot be heard reliably in the scanner)”
The scents presented were ;
· Familiar Human
· Strange Human
· Familiar Dog
· Strange Dog
In every case, each of the scents stimulated the olfactory area of the brain, but the area associated with positive expectations was stimulated maximally by the familiar human scent, negatively by the strange human and strange dog and not at all by the dog’s own scent. (I’m not clear how the negative responses were measured)
What we can take away from this is the malleability of our dog’s behaviour even in situations most humans find uncomfortable, and what every dog owner already knew, the extent of olfactory experience in the dog’s life.
It may be interesting in our next Scent Dog Detection Class to try the Familiar Human scent experiment. The complete study can be found at : http://www.sciencedirect.com/science/article/pii/S0376635714000473