A study published in Current Biology has demonstrated that there are remarkable similarities in the way that dog and human brains respond to sound, and that dog brains, like those of people, are also sensitive to acoustic cues of emotion. A study published in Current Biology has demonstrated that there are remarkable similarities in the way that dog and human brains respond to sound, and that dog brains, like those of people, are also sensitive to acoustic emotional cues.

Lead by Attila Andics, researchers from MTA-ELTE Comparative Ethology Research Group in Hungary trained 11 dogs to lay motionless in an fMRI brain scanner. This made it possible to run the same neuroimaging experiment on both dog and human participants - something that had never been done before. They captured both dogs' and humans' brain activities while the subjects listened to nearly 200 dog and human sounds, ranging from whining or crying to playful barking or laughing.

The resultant scans showed that dog and human brains include voice areas in similar locations. Not surprisingly, the voice area of dogs responds more strongly to other dogs while that of humans responds more strongly to other humans.

The researchers also noted striking similarities in the ways the dog and human brains process emotionally loaded sounds. In both species, an area near the primary auditory cortex lit up more with happy sounds than unhappy ones. Andics says the researchers were most struck by the common response to emotion across species.

There were some differences, too: in dogs, 48% of all sound-sensitive brain regions respond more strongly to sounds other than voices. That's in contrast to humans, in which only 3% of sound-sensitive brain regions show greater response to nonvocal versus vocal sounds.

The researchers say that the findings suggest that voice areas evolved at least 100 million years ago, the age of the last common ancestor of humans and dogs. It also offers new insight into humans' unique connection with our best friends in the animal kingdom and helps to explain the behavioural and neural mechanisms that made this alliance so effective for tens of thousands of years.

Andics said: "This method offers a totally new way of investigating neural processing in dogs. At last we begin to understand how our best friend is looking at us and navigating in our social environment."

Photograph: Borbala Ferenczy. Dogs at the MR Research Centre (Budapest).

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