Reduced activation in empathy core regions during observation of social interactions in patients with borderline personality disorder: an fMRI-study

Patients with Borderline personality disorder (BPD) are known to exhibit aberrant empathy and heightened sensitivity to social threat. However, the neural mechanisms underlying these observations are not fully understood. In the present study, we therefore sought to assess empathy for somatic and psychological pain during a Social Interaction Empathy Task (SIET) in female patients with BPD (n = 50) and healthy participants (n = 55) during functional magnetic resonance imaging (fMRI). We further examined pain thresholds during a pain-pressure test (PPT) to the thenar muscles, self-harm behaviour, trait empathy, alexithymia and severity of BPD symptoms. Patients with BPD showed higher pain ratings for psychological pain and neutral conditions during the SIET, and higher pain ratings for psychological pain when rating from a first-person perspective, compared to a third-person perspective. The fMRI data revealed reduced activations in clusters including the right insula and hippocampus, bilateral superior and middle frontal gyri, left middle temporal gyrus, left pre-and postcentral gyri, left putamen and right anterior cingulum in patients with BPD. Activations of the left middle temporal gyrus when observing neutral scenarios correlated negatively with alexithymia and self-harm behaviour in the whole sample. In controls, middle temporal gyrus activation during viewing psychological pain was related to perspective taking (IRI), a capacity that was notably reduced in the patient group. Patients further exhibited elevated pain thresholds during the PPT and reduced pain intensity ratings for the right thenar. The findings indicated that patients with BPD showed altered processing of social interactions, speculatively due to deficits in perspective taking.