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Patterns of laryngeal electromyography and the activity of the respiratory system during spontaneous laughter
Journal article   Peer reviewed

Patterns of laryngeal electromyography and the activity of the respiratory system during spontaneous laughter

Erich S Luschei, Lorraine O Ramig, Eileen M Finnegan, Kristen K Baker and Marshall E Smith
Journal of neurophysiology, Vol.96(1), pp.442-450
07/2006
DOI: 10.1152/jn.00102.2006
PMID: 16772517

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Abstract

Laryngeal muscle electromyography (EMG) and measures of the behavior of the respiratory system have been made during spontaneous laughter in two groups of subjects. The smaller group also had a direct measure of tracheal pressure during this behavior. Laryngeal adductors such as the thyroarytenoid (TA) and lateral cricoarytenoid (LCA) exhibited brief high-amplitude bursts of activity, at a rate of approximately 5 Hz, which were usually associated on a 1 : 1 basis with the sound bursts (ha ha ha) of laughter. The laryngeal abductor, posterior cricoarytenoid (PCA), also showed bursts of activity that were out of phase with TA and LCA. The cricothyroid (CT) was only weakly, if at all, modulated during the bursting activity of the other laryngeal muscles. Tracheal pressure usually exhibited positive pressure pulses during laughter that were often, but not always, temporally correlated to the bursts of laryngeal adductor EMG activity. Such pressure modulations appeared to precisely determine when-and if-phonation was produced during the laugh. During laughter, laryngeal EMG is highly stereotyped both within and between subjects. In most instances, this activity appears to be supported by coordinated pulses of tracheal pressure. The periaqueductal gray (PAG) has been shown in animal studies to produce emotionally indicative vocalizations, in which the laryngeal and respiratory system are coordinated. Therefore, it is suggested that the PAG is involved with the production of laughter.
Motor Activity - physiology Humans Male Laryngeal Muscles - physiology Action Potentials - physiology Respiratory Physiological Phenomena Laughter - physiology Laryngeal Nerves - physiology Laryngeal Muscles - innervation Respiratory System - innervation Periaqueductal Gray - physiology Trachea - physiology Adult Female Aged Electromyography

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