Hemispheric Asymmetry of Functional Brain Networks under Different Emotions Using EEG Data

Abstract

Despite many studies reporting hemispheric asymmetry in the representation and processing of emotions, the essence of the asymmetry remains controversial. Brain network analysis based on electroencephalography (EEG) is a useful biological method to study brain function. Here, EEG data were recorded while participants watched different emotional videos. According to the videos’ emotional categories, the data were divided into four categories: high arousal high valence (HAHV), low arousal high valence (LAHV), low arousal low valence (LALV) and high arousal low valence (HALV). The phase lag index as a connectivity index was calculated in theta (4–7 Hz), alpha (8–13 Hz), beta (14–30 Hz) and gamma (31–45 Hz) bands. Hemispheric networks were constructed for each trial, and graph theory was applied to quantify the hemispheric networks’ topological properties. Statistical analyses showed significant topological differences in the gamma band. The left hemispheric network showed significantly higher clustering coefficient (Cp), global efficiency (Eg) and local efficiency (Eloc) and lower characteristic path length (Lp) under HAHV emotion. The right hemispheric network showed significantly higher Cp and Eloc and lower Lp under HALV emotion. The results showed that the left hemisphere was dominant for HAHV emotion, while the right hemisphere was dominant for HALV emotion. The research revealed the relationship between emotion and hemispheric asymmetry from the perspective of brain networks.

Neurofunctional Symmetries and Asymmetries during Voluntary out-of- and within-Body Vivid Imagery Concurrent with Orienting Attention and Visuospatial Detection

“…These methods may be considered in contrast to auditory asymmetries probed by traditional methods such as the dichotic listening task [36], or more specific versions of it, such as computer laterometry [37]. The notion of asymmetry being dynamically functional has also been recently demonstrated in other mental states such as fatigue [38], strain [39], emotional arousal [40], and during biofeedback [33].…”

Preliminary Study on Changes of Sleep EEG Power and Plasma Melatonin in Male Patients With Major Depressive Disorder After 8 Weeks Treatment

“…Asymmetries of electrical activity in both hemispheres have been reported, especially alpha and delta power asymmetry, in patients with MDD ( 15 , 16 ). A previous study revealed the relationship between emotion and hemispheric asymmetry from the perspective of brain networks based on resting state EEG ( 17 ). Unfortunately, these findings were not based on analyses of sleep EEGs.…”

Adaptive Model for Biofeedback Data Flows Management in the Design of Interactive Immersive Environments

“…The first theory explains that the right hemisphere is dominant in the process of emotions regardless of the affective valence. The second theory justifies that the right hemisphere is responsible for processing the negative emotions, and the left hemisphere is specialized in the positive ones [23].…”

“…The process of emotions involves different parts of the central nervous system which interact between them, especially between the central and autonomic system. There are brain pathways between various cortex areas that have connections to process the emotions [23]. For example, the hypothalamus controls part of the autonomic nervous system responsible for some changes such as heart rate, skin temperature and respiration rate.…”