When the Body Feels Alone: Interoceptive Sensibility and Prefrontal Correlates of Loneliness

Loneliness is increasingly recognized as an embodied experience rooted in altered brain-body interactions. This study tested the hypothesis that individual differences in how people process and regulate bodily signals are linked to their experience of loneliness. We combined questionnaire, heartbeat counting (HBC) and discrimination (HBD) task, and heartbeat-evoked potential (HEP) measures in 39 healthy adults. Results revealed that higher loneliness was strongly associated with lower interoceptive sensibility – particularly greater worry, lower self-regulation, and reduced body trust – but not with objective interoceptive accuracy. Cluster-based permutation analysis showed that higher loneliness correlated with attenuated late HEP amplitudes (520-600 ms) over left frontal electrodes. Source localization using sLORETA suggested reduced activity in the left dorsolateral prefrontal cortex (DLPFC), and multiple regression analysis indicated that loneliness was jointly associated with lower DLPFC-related HEP activity, greater worry, and reduced self-regulation. These associations were not explained by depressive symptoms or heart rate variability. Together, these findings suggest that loneliness is associated not with impaired detection of bodily signals per se, but with altered higher-order regulation and appraisal of interoceptive processing within prefrontal circuits. This neurocognitive account proposes that altered prefrontal modulation of bodily awareness may contribute to the persistent subjective experience of social disconnection.