Testing the hypothesis that irritability is mediated by different neural mechanisms in different disorders, Dr. Jillian Lee Wiggins and researchers in Dr. Ellen Leibenluft’s Section on Bipolar Spectrum Disorders (EDB) designed a study based on the fact that patients diagnosed with either DMDD or BD have trouble recognizing emotion in faces. Using functional magnetic resonance imaging (fMRI), the researchers scanned patients in both groups as they labeled faces with expressions of varying emotional intensity as neutral, happy, fearful, or angry.