A 2019 study published in the Journal of Neuroscience by E. Hecht and colleagues investigated how selective breeding has shaped the canine brain. Using MRI scans from 62 dogs across 33 breeds, the researchers discovered that neuroanatomical variation is both significant and nonrandom, mapping onto specialized behavioral functions such as sight hunting, scent hunting, guarding, and companionship.
The team applied whole-brain independent components analysis, which revealed that specific regional subnetworks covary with each other. Importantly, these variations could not be explained by overall brain size, body size, or skull morphology, suggesting that functional specialization rather than structural constraints was the driving factor.
Phylogenetic analysis showed that most changes occurred along the terminal branches of the dog phylogenetic tree, pointing to strong, recent selection pressures in modern breeds. This aligns with the fact that dog breeds have been intensively shaped by human preferences over the last few centuries.
The findings underscore that humans have not only modified the appearance and behavior of dogs through selective breeding, but also their neuroanatomical structures. These results provide a neural basis for the observed differences in cognition, temperament, and working capabilities across dog breeds, offering new insights into the biological underpinnings of domestication and specialization.
Source: Hecht, E., Smaers, J., Dunn, W., Kent, M., Preuss, T., & Gutman, D. (2019). Significant Neuroanatomical Variation Among Domestic Dog Breeds. Journal of Neuroscience, 39, 7748–7758.
