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Is Fido really excited to see you? Or is the panting and tail wagging simply a sign that he’s anticipating a treat?

Researchers from Emory University in Atlanta are trying to answer this question and others by using MRI scans. In a new study, scientists report that they have for the first time successfully trained dogs to lie awake and still in an MRI machine for 10 to 15 seconds, long enough to complete a scan.

“We can actually capture brain images and see what parts of the brain are activating when we have hand signals or when we talk to [the dog] or when we point this way or that way. Now we can really begin to understand what a dog is thinking,” said researcher Gregory Berns, a professor of neuroeconomics at Emory, in a video about the study.

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The idea for the study was sparked after Berns learned that dogs were involved in the U.S. military’s mission to kill Osama bin Laden. “I realized dogs can be trained to jump out of airplanes and helicopters. We can certainly train them to go into an MRI so we can see what they’re thinking,” he said.

For the proof-of-concept experiment, it took researchers eight months to train two dogs to remain motionless in the machine while wearing noise-reducing earmuffs. The scientists then looked at the dogs’ brain activity in response to human hand signals indicating that they would either receive a hot dog (left hand up) or not receive a hot dog (both hands pointing toward each other horizontally). The idea was to see whether the appropriate brain regions would light up in anticipation of a reward, which they did.

That’s just the beginning. Now that researchers know they can get an unrestrained and unsedated dog to lie still in the MRI tunnel, they hope to study all kinds of canine thoughts. The Los Angeles Times reported:

For example, Berns said, they might explore whether dogs have empathy for owners by showing the dogs pictures of their owners being poked with a pin and seeing whether that triggers a pain response in the dog’s brain. They can also determine whether dogs process human language as arbitrary sound or if they have neural structures that respond to the deeper manner of language. They can see if dogs recognize their owners by sight or by smell.

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“Dog-lovers are convinced their dogs know what they’re feeling. Honestly, I’m on the fence about that. Maybe that’s because of my own dogs,” Berns told Wired Science. “Skeptics out there — a.k.a. cat people — think dogs are just good actors. I don’t think it’s quite like that. But how far it goes, I’d love to figure out.”

The study will be published Friday in the journal PLoS One.

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