Exploring neural correlates of emotional and social listening with high-density diffuse optical tomography in the auditory cortex

Listening to music impacts mood and stress levels, and may even improve cognition in older adulthood. How the brain responds to music may be different when the music evokes positive or negative emotions, when listening alone or alongside someone else. Hence, this study investigated whether the cortical, auditory responses to sad or happy music are different between solitary and social (dyadic) music listening. Using high-density diffuse optical tomography (HD-DOT), brain activity was measured in 88 volunteers, in a non-laboratory setting, while they first listened to music in a solitary, and then a dyadic, listening task. Significant differences in activation patterns were found between the two affective and social setting conditions, with the strongest differences in auditory response occurring between the social setting conditions. Additionally, comparable functional networks, namely the control, salience, and default mode networks, demonstrated higher connectivity in conditions where participants listened to music together, irrespective of musical affect. These networks also demonstrated large variations in inter-brain coherence between paired participants. This study validates HD-DOT's effectiveness in relaxed environments and highlights its potential for large-scale data collection. Our results suggest that different social settings may influence brain functional metrics, with implications for how music can be used therapeutically across different health and care settings.