Looking at dog brains

Today I was privileged to visit Dr. Greg Berns' laboratory to see awake dogs in an fMRI. In vet school, of course I saw dogs getting MRIs of their brains as part of medical diagnostics, in hunts for cancer, stroke, inflammation, etc. But because an MRI requires that the subject hold perfectly still for several minutes at a time, these dogs were under general anesthesia, which is both expensive for the owner and physically difficult on the dog.

In humans, we can use the related technology, functional MRI (fMRI), to see changes in brain activity in response to different stimuli, such as music, smells, or looking at pictures. This is a useful tool in research, for example as we try to figure out which brain areas perform which tasks. In dogs, we haven't been able to do such studies, because the only way to keep dogs still enough for an fMRI has been to anesthetize them, and obviously a sleeping dog isn't going to have a meaningful reaction to external stimuli.

At Dr. Berns' lab, they have trained dogs to hold still in an fMRI machine while resting their chins on a chin rest. Can your dog hold its head perfectly still for minutes at a time? What about in a strange room, with loud machine noises all around, with ear muffs on to protect their hearing? It's an impressive feat, and done using entirely positive methods. (The training protocol was developed by Mark Spivak of Comprehensive Pet Therapy, Inc.)

I was most impressed by the dogs' relaxed body language. They entered the machine willingly, when their owners asked them to. They lay down with their chins on the rest and waited. As I watched from behind, I could see that many of the dogs were lying on one hip or even frog-legged, in very relaxed postures, suggesting that they were comfortable being in the machine. (Have you ever had an MRI? It is a claustrophobic experience. Humans getting MRIs would benefit from the extensive conditioning preparation that these dogs had, as well as having a loved one present to feed them treats periodically!) Some dogs would balk at some points and exit the machine, at which point their handler would ask them to return and they would. Dogs always had the opportunity to leave. At the end of the test, they came out happy and wriggly.

Highlights of the day for me:

• The Boston terrier who hurled himself into the fMRI at full speed and then became rock-still for as long as his owner asked him to. That dog was committed to his fMRI experience! (Who would expect the Boston to be the calmest dog in the magnet?)
• The dogs with their ear protectors wrapped onto their heads with an elastic material normally used to attach catheters and the like. They looked hilarious.
• The treats fed to dogs on the end of long sticks so that they're easier to deliver inside the magnet. Ingenious.
• Personally getting to participate in experiments by giving hand signals to dogs who were in the magnet, watching me intently as they waited for their treats.

The joke around the lab is that these tests will tell us why our dogs really love us: are we best friends or just food dispensers? It is a joke because of course fMRI is not a test for love; science has some trouble testing for squishy concepts like that. But fMRI does give us a new  tool for guessing at what goes on in doggy heads, in addition to having to muck around with hormones like cortisol (as I have done) or strange little cognition tests like separation experiments or pointing experiments, as others have done. We have never been able to use this tool on awake animals before, so this is a huge step forward.

It was a fascinating day. I am deeply happy to see non-invasive research going on which takes the welfare of its canine participants into account, and waiting with bated breath to find out the results of the experiments I saw.


Further reading
 

• Greg Berns' home page at Emory

• Functional fMRI in awake unrestrained dogs (open access)
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