Development of a methodology to combine fMRI and EMG to measure emotional responses in patients with anorexia nervosa

Objective: Individuals with eating disorders are theorized to have basic impairments in affective appraisal and social–emotional processing that contribute to pathogenesis of the disease. We aimed to determine if facial electromyography could be used to discriminate between happy and disgust emotions during simultaneous acquisition of an fMRI BOLD sequence in efforts to establish a novel tool for investigating emotion-driven hypotheses about eating pathology. In line with standards for rigor and reproducibility, we provide detailed protocols and code to support each step of this project. Method: Sixteen adolescents with low-weight eating disorders viewed emotional faces (Happy or Disgust) and were asked to mimic their facial expression during simultaneous BOLD and EMG (Corrugator supercilli, Lavator lavii, Zygomaticus major) acquisition. Trials were repeated with the scanner off and again with scanner on (i.e., fatigue). Results: The Levator and Zygomaticus activation patterns discriminated disgust and happy faces successfully. The pattern held between scanner on and off conditions, but muscle activation attenuated in the Fatigue condition, especially for the Zygomaticus. Discussion: Simultaneous fMRI–EMG is a new tool capable of discriminating specific emotions based on muscle activation patterns and can be leveraged to answer emotion-driven hypotheses about clinical populations characterized by difficulty labeling or processing emotions.