Organization of distributed cortical connections underlying the processing of auditory information in dogs assessed by diffusion MRI.

Dogs and humans have co-evolved for millennia. This provides an opportunity to examine neural adaptations supporting cross-species communication. Previous canine fMRI studies have identified functional activations in response to human voice perception. However, the specific neural pathways involved in dogs' ability to process and respond to human language remain unknown. This study takes a data-driven approach to examine the brain connectivity supporting bidirectional communication in a large sample of dogs. We examine white matter pathways linking temporal regions, involved in the perception of communicative signals, and frontal regions, responsible for generating communicative responses. Using cortical regions with known axonal connectivity from tract tracing studies as a foundation, we applied probabilistic tractography to measure connectivity patterns in a diverse cohort of dogs (n = 110, 16 breeds). Our findings reveal that, beyond short-range intra-regional connections, consistent large-scale tracts connect the prefrontal, somatosensory, premotor, motor, and temporal lobes across subjects. Hierarchical clustering analysis revealed distinct structural organization, with sylvian regions strongly connected to motor regions and ectosylvian regions linked to higher-order frontal and prefrontal regions. This organization may suggest that the ectosylvian gyrus plays a key role in integrating auditory input with complex cognitive functions, potentially underlying cross-species communication and language processing in dogs. This study elucidates cortico-cortical communication pathways in dogs and contributes to our understanding of the neural basis of lexical processing in the canine brain.