An ERP study on the understanding of the distinction between real and apparent emotions

ERP responses to sexual cues among young women attracted to men

Previous event-related potential (ERP) studies reported larger N170, P3, and late positive potential (LPP) amplitudes to sexual than nonsexual stimuli. These ERPs may not be specifically sensitive to processing sexual cues, however, because the sexual stimuli included information beyond sexual cues (e.g., faces, bodies, social interaction) to a greater extent than comparison stimuli. We investigated ERPs to stimuli that focused on sexual and nonsexual body regions, in different states of readiness for activity, to elucidate neural responses involved in processing sexual cues. Forty cisgender, primarily white, undergraduate women who were attracted to men (M_age  = 18.6, SD = 0.9) viewed images that varied by male body part (penis, arm) and activity state (rest, poised for activity). Participants viewed 40 images per category (flaccid penises, erect penises, outstretched arms, bent arms). Electroencephalography (EEG) was recorded using a 128-channel net, time-locked to the onset of each image. Using a whole-head cluster-mass approach, we found that the P3 was sensitive to sexual readiness-P3 amplitudes were larger to erect than flaccid penises, but not to bent than outstretched arms. The N170 and LPP components did not show evidence of similarly specific responses to sexual readiness, revealing potential dissociation of different neural processes commonly elicited in response to more complex sexual stimuli. An additional novel finding was that an anterior N270-400 was sensitive to sexual readiness. Findings clarify the brain's rapid responses to sexual stimuli, setting the stage for future research aimed at better understanding the neurocognitive processes that contribute to the coordination of sexual arousal.

What is missing in the study of emotion expression?

While approaching celebrations for the 150 years of "The Expression of the Emotions in Man and Animals", scientists' conclusions on emotion expression are still debated. Emotion expression has been traditionally anchored to prototypical and mutually exclusive facial expressions (e.g., anger, disgust, fear, happiness, sadness, and surprise). However, people express emotions in nuanced patterns and - crucially - not everything is in the face. In recent decades considerable work has critiqued this classical view, calling for a more fluid and flexible approach that considers how humans dynamically perform genuine expressions with their bodies in context. A growing body of evidence suggests that each emotional display is a complex, multi-component, motoric event. The human face is never static, but continuously acts and reacts to internal and environmental stimuli, with the coordinated action of muscles throughout the body. Moreover, two anatomically and functionally different neural pathways sub-serve voluntary and involuntary expressions. An interesting implication is that we have distinct and independent pathways for genuine and posed facial expressions, and different combinations may occur across the vertical facial axis. Investigating the time course of these facial blends, which can be controlled consciously only in part, is recently providing a useful operational test for comparing the different predictions of various models on the lateralization of emotions. This concise review will identify shortcomings and new challenges regarding the study of emotion expressions at face, body, and contextual levels, eventually resulting in a theoretical and methodological shift in the study of emotions. We contend that the most feasible solution to address the complex world of emotion expression is defining a completely new and more complete approach to emotional investigation. This approach can potentially lead us to the roots of emotional display, and to the individual mechanisms underlying their expression (i.e., individual emotional signatures).

Oxytocin weakens self-other distinction in males during empathic responses to sadness: an event-related potentials study

By making use of event-related potential (ERP) technology, a randomized, double-blind, between-subject design study was performed in order to investigate whether OXT can weaken men’s self-other distinction during empathic responses to sad expressions. In the two experimental tasks, 39 male subjects were asked to either evaluate the emotional state shown in a facial stimulus (other-task) or to evaluate their own emotional responses (self-task). The results revealed that OXT reduced the differences in P2 (150–200 ms) amplitudes between sad and neutral expressions in the self-task but enhanced P2 to sad expressions in the other-task, indicating OXT’s role in integrating the self with others instead of separating them. In addition, OXT also reduced the LPC (400–600 ms) amplitudes between sad-neutral expressions in the self-task, implying that OXT’s weakening effects on the self-other distinction could occur at both the early and late cognitive control stages of the empathic response.

Gender differences in affective sharing and self-other distinction during empathic neural responses to others' sadness

Self-other distinction, the separation between self and other, is a prerequisite for empathy through which individuals share another individual's feelings. Prior research suggests that females are better at recognizing and sharing others' emotions, whereas males perform better at self-other distinction. It is unclear, however, whether this superiority in the self-other distinction occurs in males throughout the experience of empathy or only at some stages of the empathic process. The present study utilized event-related potentials (ERPs) to investigate this issue. In two separate experimental tasks, subjects were instructed to either judge the emotions shown on a face (other-task) or evaluate their own affective responses to the emotions shown on a face (self-task). The results of the other-task revealed that unlike males, females displayed increased P2 (190-240 ms) amplitudes to sad expressions compared with neutral expressions. This finding might be associated with an improved ability to recognize and share the emotions of others in females. In contrast, only males exhibited larger P2 amplitudes to sad expressions compared with neutral expressions during the self-task. This awareness of one's own emotions in response to another individual might reflect a distinction between the self and the other at an early stage in males. At the late cognitive controlled stage, gender differences became weak. However, the emotion effects in each task for both genders were positively correlated with self-reported cognitive empathy, which was indexed by the perspective taking (PT) and fantasy (FS) subscale, but not with affective empathy.