Disturbed interoception might contribute to the emotional dysregulation in borderline personality disorder (BPD). Müller and coauthors studied heartbeat evoked potentials (HEPs) in medication-free patients with BPD, patients with BPD in remission, and matched healthy control subjects. Heartbeat evoked potentials indicate the cortical representation of signals from the cardiovascular system. Patients with BPD had significantly reduced HEP amplitudes, which were correlated with emotional dysregulation and positively associated with insula and anterior cortex gray matter volume. Garfinkel and coauthors discuss the importance of the findings for a theory of perturbed interoception in BPD.