Brain activation in central auditory pathway and corticolimbic areas depend on the emotional valence of conspecifics vocal sounds in pigs

Background Pig vocalizations reflect emotional states, varying with arousal and valence, yet the underlying neural mechanisms remain unclear. This study used functional magnetic resonance imaging (fMRI) to examine brain responses to emotionally varied pig vocalizations, focusing on regions associated with emotion, reward, and social processing, with implications for animal welfare and cross-species emotional research. Materials & Methods Eight healthy 2-month-old pigs underwent auditory brainstem response (ABR) testing and fMRI during playback of vocalizations with positive or negative valence via MRI-compatible earphones on a 1.5T scanner. Data were analyzed using voxel- and ROI-based statistics in SPM12 with small volume correction (SVC). After excluding three pigs due to hearing anomalies or MRI artefacts, five were included in the final analysis. Results Both positive and negative vocalizations activated core auditory regions (IC, GN, AC, p < 0.0001), with positive sounds eliciting stronger activation (p < 0.01). Negative calls uniquely engaged limbic areas, including the amygdala and dorsal striatum (p < 0.01), indicating distinct valence-specific processing. Conclusion Piglets can differentiate emotional vocalizations even under anesthesia, with distinct brain responses for positive and negative calls in regions linked to hearing, emotion, and reward. These findings advance understanding of pig cognition and emotion, supporting their use as a model for research in animal welfare, emotion, and auditory neuroscience, and contribute to the development of fMRI protocols for acoustic stimulation in pigs.