[Analysis of elicited EEG synchronization and desynchronization in emotional activation: temporal and topographic...

Event-related synchronization (ERS) and desynchronization (ERD) in delta, theta1, theta2, alpha1, alpha2, beta1, beta2, beta3, and gamma were measured in 20 healthy right-handed subjects in response to IAPS stimuli with low, moderate, and high arousal reactions. The 62-channel EEG was simultaneously recorded while subjects viewed sequentially presented pictures and subjectively rated them after each presentation. The results show that emotionally loaded stimuli induced higher ERS in the delta, theta1, theta2, beta1, beta3, and gamma bands along with combined ERD and ERS effects in alpha2 band. As to hemispheric asymmetries, the effects of emotional arousal were restricted not only to right parietal (theta1 and theta2 ERS, alpha2 ERD) but also to left frontal (theta2 ERS) regions. In terms of affective chronometry, lower theta was the first to catch the affective salience of incoming stimuli (time window 0-600 ms after the stimulus input). For theta2, alpha2, and gamma bands this process was delayed to 600-1000 ms.