NEURAL DYNAMICS OF STATE-DEPENDENT SOCIAL BEHAVIOR FOLLOWING DIVERSE SOCIAL AND PHYSIOLOGICAL CHALLENGES

Internal states play a critical role in generating adaptive behaviors by integrating external environmental stimuli. Although such internal state changes profoundly influence social behavior, the underlying neural mechanisms remain largely unclear. In this study, we investigated how different types of internal state changes affect social interaction patterns and associated neural activity in mice. We utilized local field potential (LFP) recordings to compare the effects of social stimuli, involving exposure to either female or male intruders, and physiological stimuli, including water deprivation and water re-access, on social behavior and neural dynamics. Both forms of social stimuli led to reductions in social interaction, with male intruders inducing a stronger and more sustained decrease. In the physiological stimulus group, water re-access reduced social interaction, whereas water deprivation showed the opposite trend. C-fos expression analysis revealed distinct activation patterns in the anterior insular cortex (AI), anterior cingulate cortex (ACC), and lateral hypothalamus (LH) depending on the type of internal state. LFP analysis further demonstrated that social stimuli primarily modulated ACC-centered networks, whereas physiological stimuli affected LH-centered networks. These findings suggest that social and physiological challenges regulate social behavior through distinct neural mechanisms. This study provides new insights into the neural pathways underlying internal state-dependent modulation of social behavior and advances our understanding of the neurobiological basis of social interaction.