Detection of facial mimicry by electromyography during fMRI scanning
Pictures were presented in a block design showing 20 consecutive faces with the same expression for 0.5 s each with an interval of 0.5 s (Fig. 1) Four blocks were shown of each emo tion. EMG was recorded using pre gelled circular 1 cm diameter radiotrans lucent electrodes on 3.8 cm circular vinyl backing. Radiotranslucent clip leads were connected through a patch panel connector to Biopac EMG amplifiers in the control room. To remove scanner noise, EMG signals were processed ac cording to a procedure proposed by Heller et al