Frontal EEG alpha asymmetry changes while watching emotional film clips and role of difference pair of frontal electrodes: A preliminary study (original) (raw)

Frontal alpha asymmetry (FAA) has been found to be a neuro-biomarker of affective styles associated with emotional valence and motivational direction. It has been hypothesized the greater left frontal activation reflects the positive (approach) behaviors, whereas the greater right frontal activation reflects the negative (withdrawal) behaviors. However, the role of hemispheric lateralization on emotions is still debated. Moreover, the frontal electrodes consisting of F4/F3 and F8/F7 pairs are commonly used in FAA analysis, but few studies have examined the role of different frontal electrode pairs. This study aimed to clarify the FAA in response emotional clips comparing to resting-state and the influence of difference pairs of frontal sites (F4/F3: medial–frontal sites vs. F8/F7: lateral–frontal sites). The participant were 10 healthy females (aged 20–32 years; M = 25.80, SD = 4.85). Two sets of emotional clips (4 clips per set) were used to elicit target emotional states (sadness, fear, happiness, and neutral). The FAA was calculated using the equation: ln[right] − ln[left] alpha power (8.5–13 Hz). The results found the significantly decreased FAA at F4/F3 pair in response to negative clips (sad; t(9) = 2.787, p = 0.021, fear; t(9) = 2.344, p = 0.044) and significantly increased FAA at F8/F7 pair in response to neutral clips (t(9) = −2.902, p = 0.018) when compared to resting-state. Moreover, the significantly changes among emotional clips can be detected from FAA. All FAA scores from F4/F3 were positive, whereas most FAA scores from F8/F7 were negative. These findings indicated that FAA is associated with emotional response, especially with negative stimuli, and is still valuable tool for studying affective response. However, the selection of frontal electrode pairs is also important. Finally, the difference of alpha power between left and right frontal electrodes seem to be more important than positive or negative FAA values.