Motor commands of facial expressions: the bereitschaftspotential of posed smiles.
Electroencephalographic (EEG) premotor potentials with negative polarity like the Bereitschaftspotential (BP) are known to precede self-paced voluntary movements of the limbs and other body parts. This is however the first report of such premotor potentials before posed smiles. Scalp EEG was recorded in 16 healthy participants performing self-paced unilateral and bilateral smiles and unilateral finger movements. Amplitudes over six central electrodes and voltage distributions over the entire scalp were compared across conditions at time of EMG-onset, thus focusing on the late BP. Results show the presence of a premotor potential before posed smiles with a later onset, symmetrical bilateral distribution, and smaller amplitude at time of movement-onset, compared to finger movements. Future studies should investigate the BP before various types of emotional and non-emotional facial expressions.
Korb
Sebastian
S
Department of Psychology, Swiss Center for Affective Sciences, University of Geneva, 7, rue des Battoirs, Geneva 1205, Switzerland. Sebastian.Korb@pse.unige.ch
Grandjean
Didier
D
Scherer
Klaus
K
D000328:Adult; D000704:Analysis of Variance; D001931:Brain Mapping; D003265:Contingent Negative Variation / Q000502:physiology*; D004576:Electromyography; D019054:Evoked Potentials, Motor / Q000502:physiology; D005149:Facial Expression; D005260:Female; D005385:Fingers / Q000294:innervation; D006801:Humans; D008297:Male; D009068:Movement / Q000502:physiology*; D010775:Photic Stimulation / Q000379:methods; D012904:Smiling / Q000502:physiology*; D013997:Time Factors