Intracortical Functional Connectivity During Deep Sleep Exposes Prosocial Preferences

Prosociality is critical for cohesive community functioning and has been recognized as a public health priority. Recently, increased slow-wave activity during deep sleep in the right temporoparietal junction (TPJ), a key component of the social brain, has been shown to be associated with stronger prosocial preferences. Here, we investigate connectivity between the right TPJ and other regions of the social brain as a marker of inter-individual differences in prosocial preferences. Whole-night high-density sleep electroencephalography (EEG) recordings were obtained from 54 participants (mean age = 21.5 ± 2 years; 28 females) at their homes. We then employed source localization to derive intracortical EEG functional connectivity during deep sleep in the slow-wave frequency range (0.8 to 4.6 Hz) and correlated connectivity between the right TPJ and 23 other key social brain regions with prosocial preferences. Prosocial preferences were assessed in an incentivized public goods game with real monetary consequences. We found a negative correlation between prosocial preferences and connectivity for 22 of the 23 analyzed connections. Of those, six connections demonstrated a significant negative correlation with prosocial preferences after adjusting for multiple testing (-0.36 < r < -0.3; 0.006 < p < 0.038). These findings indicate lower functional connectivity of the right TPJ with other social brain regions during deep sleep in individuals with stronger prosocial preferences, suggesting that the benefits of deep sleep for prosocial decision-making may be enhanced when the right TPJ reduces its interactions within the social brain during this sleep stage.