Müller and colleagues1 present a study showing that an electroencephalographic signature of the brain’s representation of internal bodily responses (the amplitude of heartbeat evoked potential) is abnormally attenuated in patients with borderline personality disorder (BPD). This deficit predicts symptoms, including the degree of emotional instability, and correlates with structural differences in the gray matter volume in the insula and the anterior cingulate cortex, brain regions engaged during emotional regulation and implicated in the integrative control of mind and body. Patients with BPD in remission show a more normative heartbeat evoked potential, suggesting that strategies to improve mental and physiological integration may enhance psychotherapeutic interventions for this patient group.