Breeding has given different dogs distinct brain shapes

Brain regions involved in smelling and tasting show some of the biggest differences

Brain scans from 33 dog breeds revealed a broad variation in regions involved in scent hunting, guarding and companionship.

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For centuries, dog breeders have been shaping the way the world’s canines look and behave. Turns out, that meddling in doggy evolution has sculpted the pups’ brains, too.

A team of researchers scanned the brains of 62 purebred dogs representing 33 breeds. They used MRI, or magnetic resonance imaging, to map the shapes of brain structures. Their results show that dog brains are not all alike. The shapes of various brain regions can differ broadly by the breed. The research may guide future studies on how brain structure relates to behavior.

The new findings appeared September 2 in the Journal of Neuroscience.

Erin Hecht studies brain evolution at Harvard University in Cambridge, Mass. She was part of the team that conducted the new study. The distinct brain shapes were not simply due to the breed’s different head shapes, the team found. Nor were differences due to the size of the dogs’ brains or bodies. Instead, Hecht and her colleagues conclude, humans’ selective breeding of their dogs have shaped the animals’ brains, bit by bit.

The dogs were scanned at the Veterinary Teaching Hospital at the University of Georgia at Athens. This study was not designed to directly link brain shape to behavior. But the results do offer some hints. Some parts of the brain varied more than others. Smell and taste regions, for instance, varied a lot between breeds. Those areas may support specialized behaviors that often serve people, earlier studies have suggested. Such behaviors include hunting by smell, guarding and providing companionship.

The authors assumed the dogs in the study were all pets. Working dogs undergo extensive training for specialized jobs, such as herding sheep, finding bombs or guiding the blind. It’s possible that such highly trained dogs might have even more distinct brains.

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Certain brain regions take on a different shape in a basset hound’s brain (left) than the brain of a border collie (right).
Marc Kent & Erin Hecht

Laura Sanders is the neuroscience writer. She holds a Ph.D. in molecular biology from the University of Southern California.

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