Complexity-based analysis of the coupling between facial muscle and brain activities

• Published in: Biomedical signal processing and control Vol. 67; p. 102511
• Main Authors: Soundirarajan, Mirra, Aghasian, Erfan, Krejcar, Ondrej, Namazi, Hamidreza
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.05.2021
• Subjects: Brain; Complexity; Facial muscle; Fractal theory; Odors; Sample entropy; Sample entropy; Brain; Fractal theory; Facial muscle; Odors; Complexity
• ISSN: 1746-8094; 1746-8108
• DOI: 10.1016/j.bspc.2021.102511

•Human facial muscles are controlled by the brain, and therefore there should be a correlation between their activities.•We decoded the coupling between facial muscles and brain by fractal and sample entropy-based analysis of EMG and EEG signals.•Based on the results, fractal exponents and sample entropies of EMG and EEG signals are coupled in different conditions. The human body consists of different muscles. Investigation of facial muscle activities is very important since they are responsive to different kinds of stimuli that humans receive. The brain controls and regulates the activities of human’s muscles. In this work, we evaluated the coupling among the facial muscles and brain activities for twelve subjects (7 M and 5 F) that were stimulated using three odors (pineapple, banana, and vanilla flavors as olfactory stimuli) with different molecular complexities. Using fractal theory and sample entropy, we studied how the complexity of facial muscles’ reaction through Electromyography (EMG) signals is linked to the complexity of the brain’s response through Electroencephalography (EEG) signals due to olfactory stimulation. The results showed significant changes (P<0.05) in the complexities of EMG and EEG signals in response to the applied odors. Besides, the changes in the complexity of EEG and EMG signals are strongly correlated in the case of fractal dimension (r=-0.947) and sample entropy (r=-0.774). This analysis method can be applied to other physiological signals to investigate the coupling between the activities of other organs and brain activity.