Preliminary evidence for context-dependent modulation of interoceptive signals in social evaluation

Interoception, the brain's processing of internal bodily signals, has emerged as a key mechanism linking body and mind. Yet it remains unresolved whether this processing operates automatically or is selectively modulated depending on context. Here, we used heartbeat-evoked potentials (HEPs) as a cortical marker of interoception, in combination with skin conductance responses (SCRs), to compare interoceptive processing between social (trustworthiness) and perceptual (symmetry) face evaluation tasks in which affective meaning is not task-relevant. HEP amplitudes over the left parietal cortex (126-186 ms after the R-peak) differentiated trustworthy from untrustworthy faces only during trust evaluation, not symmetry evaluation, providing preliminary evidence consistent with context-dependent modulation of interoceptive neural signals. Trust evaluations also elicited larger SCRs for untrustworthy faces, and HEPs and SCRs showed trial-by-trial associations, suggesting a relationship between bodily arousal signals and interoceptive processing during social-affective evaluation. Complementary fMRI analyses revealed recruitment of the precuneus, vmPFC, and angular gyrus during trust evaluation, with only the precuneus exhibiting differential activation between trustworthy and untrustworthy faces. Together, these findings provide preliminary evidence that interoceptive neural and autonomic signals may vary with evaluative context, becoming more pronounced when participants explicitly judge the social meaning of faces.