Corrugator Muscle Regions Research Articles

Sex Differences Found in Facial EMG Activity Provoked by Viewing Pleasant and Unpleasant Photographs

50 male and 50 female participants' facial electromyographic (EMG) activity at the left corrugator and zygomatic muscle regions and self-reports of emotions were recorded while they were viewing Pleasant and Unpleasant photographs. Analysis showed that the ratio of EMG power between the periods of photograph viewing and baseline at the zygomatic muscle region was significantly higher than that at the corrugator muscle region while viewing Pleasant photographs and that the EMG ratio at the corrugator muscle region was significantly higher than that at the zygomatic muscle region while viewing Unpleasant photographs. Further analysis indicated that compared to men, women reported relatively higher feelings of pleasantness and generated significantly higher EMG ratios at the zygomatic muscle region while viewing Pleasant photographs and women reported significantly less feelings of pleasantness and generated significantly higher EMG ratios at the corrugator muscle region while viewing Unpleasant photographs. These results demonstrate the sex effects on emotion expression and associated EMG responses while viewing emotion provoking photographs.

Study of Posed Emotion in Facial EMG Asymmetry

37 subjects' facial electromyographic activity at the corrugator and zygomatic muscle regions were recorded while they were posing with happy and sad facial expressions. Analysis showed that the mean value of EMG activity at the left zygomatic muscle region was the highest, followed by the right zygomatic, left corrugator, and right corrugator muscle regions, while a happy facial expression was posed. The mean value of EMG activity at the left corrugator muscle region was the highest, followed by those for the right corrugator, left zygomatic, and right zygomatic muscle regions while a sad facial expression was posed. Further analysis indicated that the power of facial EMG activity on the left side of the face was stronger than on the right side of the face while posing both happy and sad expressions.

Effects of Viewing Pleasant and Unpleasant Photographs on Facial EMG Asymmetry

40 subjects' facial electromyographic (EMG) activity at the corrugator and zygomatic muscle regions were recorded while they were viewing pleasant and unpleasant photographs. Analysis showed that the EMG activity at the left zygomatic muscle region generated the highest power, followed by the right zygomatic, left corrugator, and right corrugator muscle regions, while viewing pleasant photographs. The EMG activity at the left corrugator muscle region generated the highest power, followed by the right corrugator, left zygomatic, and right zygomatic muscle regions, while viewing unpleasant photographs. Further statistical analysis indicated that the EMG activities at the left corrugator region generated significantly higher power than those at the right corrugator region while viewing unpleasant photographs. It was concluded that the intensity of facial EMG activity on the left side of the face was stronger than the right side of the face during the process of emotional expression.