Variability of Frontal Alpha Wave in Response to Mood Induction via Visual Stimulus: A Quantitative Electroencephalographic Study

Abstract

Background: One of the prime areas in psychiatry is concerned with assessing emotions. Assessment of physiologic responses can be attained by various approaches. One of them is analyzing Electroencephalography (EEG). Objectives: In current study, we aimed to assess Alpha wave in frontal region after inducing specific emotion by showing evocative video clips. Materials and Methods: After a baseline in Eye Open situation recording, we showed 5 video clips that each induced specific emotions from five major ones (Neutral, Happiness, Sadness, Anger, Fear) to 66 healthy individuals, including 33 males and 33 females between 20 - 40 years old and EEG recording was continued simultaneously. Then, we analyzed their brain waves. Absolute power of Alpha wave Bands (Alpha 1 and Alpha 2) in frontal region (FZ, F4, F3) was analyzed via Wilcoxon test. Results: With respect to eye open situation, all video clips made significant change in Alpha 2 in F3 and F4 (P < 0.001) but not in Fz except for sadness. Sad inductive clip made a significant increase in Alpha 2 in Fz, also Alpha 1 in F3 and F4 (P < 0.001). Fz had no significant variability in all other emotions. Conclusions: The most trenchant impact with respect to Alpha band was sadness, and the most exclusive finding in FZ was Alpha 2. Nonetheless, in two other zones (F3, F4), Alpha 1 was exclusive and Alpha 2 variability was non-exclusive. It appears plausible that sadness activates neuron groups, which are involved in generating Alpha waves.