Aching face and hand: the interoceptive attentiveness and social context in relation to empathy for pain

This research explored how the manipulation of interoceptive attentiveness (IA) can influence the frontal (dorsolateral prefrontal cortex (DLPFC) and somatosensory cortices) activity associated with the emotional regulation and sensory response of observing pain in others. 20 individuals were asked to observe face versus hand, painful/non-painful stimuli in an individual versus social condition while brain hemodynamic response (oxygenated (O2Hb) and deoxygenated hemoglobin (HHb) components) was measured via functional Near-Infrared Spectroscopy (fNIRS). Images represented either a single person (individual condition) or two persons in social interaction (social condition) both for the pain and body part set of stimuli. The participants were split into experimental (EXP) and control (CNT) groups, with the EXP explicitly required to concentrate on its interoceptive correlates while observing the stimuli. Quantitative statistical analyses were applied to both oxy- and deoxy-Hb data. Firstly, significantly higher brain responsiveness was detected for pain in comparison to no-pain stimuli in the individual condition. Secondly, a left/right hemispheric lateralization was found for the individual and social condition, respectively, in both groups. Besides, both groups showed higher DLPFC activation for face stimuli presented in the individual condition compared to hand stimuli in the social condition. However, face stimuli activation prevailed for the EXP group, suggesting the IA phenomenon has certain features, namely it manifests itself in the individual condition and for pain stimuli. We can conclude that IA promoted the recruitment of internal adaptive regulatory strategies by engaging both DLPFC and somatosensory regions towards emotionally relevant stimuli.