Selection and learning shape communication networks in the dog brain.

Over tens of thousands of years of coevolution with humans, dogs have developed exceptional communicative abilities through both inherited adaptations and individual learning. Using diffusion MRI tractography in 108 dogs (50 males and 58 females), we disentangled how long-term selection and short-term training shape the neural architecture of communication. Comparing modern breeds to premodern dogs revealed that selective breeding for close interaction with humans has rewired communication-related networks, increasing hemispheric asymmetry and altering temporal and associative connectivity involved in vocal and lexical processing. In contrast, training induced localized plasticity: trained and released service dogs differed in sensorimotor and associative pathways supporting cue interpretation and response execution. Connectivity strength further predicted trainability, with higher behavioral scores linked to stronger cortical but weaker medial geniculate connections. Notably, trained dogs showed enhanced coupling between vocal premotor and secondary auditory regions associated with receptive vocabulary. Thus, the dog brain's communicative capacity reflects selection and experience acting across evolutionary and individual timescales.Significance Statement Dogs provide a unique model for understanding how human influence shapes brain communication systems across evolutionary and individual timescales. Here, we show that artificial selection and training leave dissociable signatures in the dog brain. Selective breeding for human-oriented roles is associated with broad changes in hemispheric asymmetry and communication-related connectivity, especially within temporal and associative networks. In contrast, intensive service-dog training is linked to more localized reconfiguration of sensorimotor and auditory-premotor pathways involved in interpreting cues and executing responses. Connectivity strength also predicts trainability across dogs. These findings suggest that canine communicative abilities emerge from the combined effects of inherited selection pressures and lifetime learning, revealing how experience and evolution jointly shape neural networks supporting interspecies communication.