Dog brain structure varies between breeds and is correlated with specific behaviors, according to new research. These findings show how, by selectively breeding for certain behaviors, humans have shaped the brains of their best friends.
For several hundred years, humans have selectively bred dogs to express specific physical and behavioral characteristics. The researchers examined the effects of this selective pressure on brain structure by analyzing magnetic resonance imaging scans of 33 dog breeds. The research team found a wide variation in brain structure that was not only related to body size or head shape.
The team then examined the brain regions with the most variability between races. This generated maps of six brain networks, with suggested functions ranging from social bonding to movement, each of which was associated with at least one behavioral trait. The variation in behavior between races was correlated with anatomical variation in the six brain networks.
Dog breeds are known to vary in cognition, temperament, and behavior, but the neural origin of this variation is unknown. In an MRI-based analysis, they found that brain anatomy is significant with behavioral specializations such as scent seeking, scent hunting, guarding and companionship. Neuroanatomical variation is not only driven by brain size, body size, or skull shape, and targets specific networks of regions. Nearly all identified variation occurs in the terminal branches of the phylogenetic canine family tree, indicating strong recent selection in individual breeds. These results indicate that selective breeding has significantly altered the brains of different sexes of domestic dogs in different ways.
