Event-related EEG oscillatory responses elicited by dynamic facial expression

Abstract

Background Recognition of facial expressions (FEs) plays a crucial role in social interactions. Most studies on FE recognition use static (image) stimuli, even though real-life FEs are dynamic. FE processing is complex and multifaceted, and its neural correlates remain unclear. Transitioning from static to dynamic FE stimuli might help disentangle the neural oscillatory mechanisms underlying face processing and recognition of emotion expression. To our knowledge, we here present the first time–frequency exploration of oscillatory brain mechanisms underlying the processing of dynamic FEs. Results Videos of joyful, fearful, and neutral dynamic facial expressions were presented to 18 included healthy young adults. We analyzed event-related activity in electroencephalography (EEG) data, focusing on the delta, theta, and alpha-band oscillations. Since the videos involved a transition from neutral to emotional expressions (onset around 500 ms), we identified time windows that might correspond to face perception initially (time window 1; first TW), and emotion expression recognition subsequently (around 1000 ms; second TW). First TW showed increased power and phase-locking values for all frequency bands. In the first TW, power and phase-locking values were higher in the delta and theta bands for emotional FEs as compared to neutral FEs, thus potentially serving as a marker for emotion recognition in dynamic face processing. Conclusions Our time–frequency exploration revealed consistent oscillatory responses to complex, dynamic, ecologically meaningful FE stimuli. We conclude that while dynamic FE processing involves complex network dynamics, dynamic FEs were successfully used to reveal temporally separate oscillation responses related to face processing and subsequently emotion expression recognition.

Detrending Moving Average, Power Spectral Density, and Coherence: Three EEG-Based Methods to Assess Emotion Irradiation during Facial Perception

“…They indicate a greater reactivity of the high-frequency part of the EEG spectral parameters, especially in response to the negative modality of demonstrated faces. Apart from that, emphasis was placed on the high significance of the theta EEG oscillations in the anterior cortical areas alongside high-frequency bands in the temporal, parietal and occipital regions (presumably including the fusiform gyrus), which play a crucial role in the mechanisms of facial perception and processing [32][33][34].…”

Review of EEG Affective Recognition with a Neuroscience Perspective

“…In the change detection of an emotion task, it was found that all modes of emotion changes resulted in enhanced theta synchronization, which correlates with the performance accuracy of subjects during emotion change detection, but the same cannot be concluded for alpha or beta bands [101]. Another study by Aktürk and team showed increased power and higher phase-locking values for theta (as well as all other frequencies) in the right parietal region when a face was first perceived and that this increase in power is greater for emotional expressions than neutral ones [132]. In addition, they found that theta phase-locking values were higher for fearful than happy or neutral expressions.…”