Brains of dogs and humans have 'voice areas' in same places

Date: Feb-21-2014The first study to compare brain scans of non-primates and humans has revealed

that both dogs and humans have dedicated brain areas for voices, and they react in similar ways

when processing emotional cues.

First author Dr. Attila Andics, of MTA-ELTE Comparative Ethology Research Group in Budapest,

and colleagues report their findings in the Cell Press journal Current Biology.

"Although parallel evolution cannot be excluded," write the researchers, the study suggests

specialized voice areas in the brain began developing over 100 million years ago, when humans

and dogs last shared an ancestor. This is much earlier than expected.

The findings also reveal new clues about mechanisms of brain and behavior that may explain

the unique connection that has existed between humans and dogs for tens of thousands of

years.

Dr. Andics says the social environment of dogs and humans is similar, and their results show

they may also use similar brain mechanisms to process social information, which may explain why

the two species make such successful companions.


To conduct their unique experiment, which involved taking the same functional magnetic

resonance imaging (fMRI) brain scans of both humans and dogs, the researchers trained 11 dogs to

lie still in the scanner.

Dr. Andics says they were interested in finding out, for example, "how do dogs process dog

sounds, and how similar it is to the way humans process human sounds."

Same areas in dog and human brains respond to vocal sounds

To conduct their experiment, the researchers trained 11 dogs to

lie still in the fMRI scanner.
Image credit: Eniko Kubinyi

While in the scanner, the canine and human participants listened to nearly 200 different

vocal sounds of people and dogs, many with emotional connotations, such as whining, crying,

laughing and playful barking.

The fMRI images showed that the same areas in the brains of both dogs and humans respond to

vocal sounds.

And it came as no surprise to the researchers that the responses were strongest

when the participants listened to sounds of their own species.

Plus, when they played vocal sounds loaded with emotional cues, the researchers found

striking similarities in the brain responses of both humans and dogs, as they note:

"Our findings also reveal that sensitivity to vocal emotional valence cues engages similarly

located non-primary auditory regions in dogs and humans."

For instance, when the participants heard "happy" sounds, in both

species, the same part of the brain lit up more than for "unhappy" sounds.

Dog and human brains respond differently to non-vocal sounds

When the participants heard "happy" sounds, the same part of the brain lit up more than for "unhappy" sounds.
Image credit: Borbala Ferenczy

Dr. Andics says they were very struck by these similarities. However, there were also some

key differences.

For example, reaction to non-vocal sounds compared with vocal sounds differed greatly between

the species.

In dogs, 48% of their sound-sensitive brain regions responded more strongly to non-vocal sounds than vocal sounds, compared with only 3% of sound-sensitive brain regions in

humans.

The researchers say the study is a first step in helping understand how our four-legged

friends are so good at sensing our feelings.


Dr. Andics says their method offers a completely new approach to looking at dogs' brains and

how they work, so we can "begin to understand how our best friend is looking at us and

navigating in our social environment."

In August 2013, Medical News Today learned of another intriguing study looking at

dogs and humans, where researchers in Japan concluded that owners' yawns are contagious to

dogs, and the response is likely empathic, rather than a result of stress.

Should this be

confirmed, then the researchers say it is significant because it could become a powerful tool for

exploring the root of empathy in animal evolution.

Written by Catharine Paddock PhD




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