UC San Diego

Social pain, the emotional pain caused by aversive experiences with one’s social group, can have deleterious effects on both mental and physical health. The “pain overlap theory” proposes that the experience of social pain can overlap with and modulate physical pain. However, we do not know if a neural substrate exists where social and physical pain overlap. To address this gap, in this dissertation, I designed a novel Social Exclusion paradigm, which we have named the “Fear of Missing Out” (FOMO) task in which mice are separated from their cagemates by a switchable glass divider and observe their cagemates collectively consume a reward. Chapter 1 explores the characterization of novel behavioral motifs during Social Exclusion and the subsequent changes to different modalities of physical pain. Using unsupervised machine learning techniques, we have discovered a “Active Coping” in which mice are more likely to climb to, rear near, or orient towards the social group, which is elevated during Social Exclusion. After Social Exclusion, mice also have enhanced nocifensive responses. Chapter 2 investigates the overlap of social and physical pain within the anterior insular cortex. Results indicate that social and physical pain do not spatially overlap at the single unit, but rather Social Exclusion induces a change in the population response to physical pain and alters the encoding of nociceptive stimuli in the aIC. This change in physical pain encoding is mediated by the recruitment of the endocannabinoid and oxytocin neuromodulatory systems. Overall, the results from this dissertation suggest we have generated a Social Exclusion paradigm within rodents that successfully modulates the sensory perception of physical pain and that the anterior insular cortex can effectively integrates social and physical pain using neuromodulation,