Coherence Analysis of EEG Signal in Happy and Sad Emotions During Visual Stimulation

Emotions play a crucial role in human life, influencing various aspects such as thoughts, behavior, and physical health. Understanding the neural mechanisms underlying emotions, particularly sadness, is essential. This study explores the relationship between brain activity associated with sad and happy emotions and the functioning of the left and right hemispheres during visual processing using coherence analysis of electroencephalogram (EEG) signals. When the coherence value is low, there is no correlation between the two compared conditions. EEG recordings were obtained from 25 participants using an OpenBCI device, and specific channels (Fp1-Fp2, F7-F8, and O1-O2) related to attention, emotion expression, and visual processing were selected. The recorded data underwent preprocessing to remove artifacts, and subsequent feature extraction was performed using coherence analysis in the gamma sub-band. The results of this study demonstrate alignment with the existing theory that each hemisphere has distinct functions when experiencing feelings of sadness and happiness, as evidenced by the observation of a weak coherence percentage in all hemisphere comparisons between Fp1-Fp2, F7-F8, and O1-O2 (all coherence value is <40%). Another finding in this study is that the human brain works harder when watching sad videos than happy videos. Taking gender into consideration, the research indicates that the male brain is more active under happiness conditions compared to females.