Neural mechanisms of the automatic processing of emotional information from faces and voices

Abstract

Theoretical accounts suggest an increased and automatic neural processing of emotional, especially threat-related, facial expressions and emotional prosody. In line with this assumption, several functional imaging studies showed activation to threat-related faces and voices in subcortical and cortical brain areas during attentional distraction or unconscious stimulus processing. Furthermore, electrophysiological studies provided evidence for automatic early brain responses to emotional facial expressions and emotional prosody. However, there is increasing evidence that available cognitive resources modulate brain responses to emotional signals from faces and voices, even though conflicting findings may occur depending on contextual factors, specific emotions, sensory modality, and neuroscientific methods used. The current review summarizes these findings and suggests that further studies should combine information from different sensory modalities and neuroscientific methods such as functional neuroimaging and electrophysiology. Furthermore, it is concluded that the variable saliency and relevance of emotional social signals on the one hand and available cognitive resources on the other hand interact in a dynamic manner, making absolute boundaries of the automatic processing of emotional information from faces and voices unlikely.

Processing of angry voices is modulated by visual load

“…The plot shows the difference of parameter estimates (mean and standard error) of the mean activation of the amygdala across experimental conditions. investigate the topography and time sequence of automatic brain responses to emotional expressions of faces and voices under attentional load, since several electrophysiological results suggest automatic responses to facial expressions even under high cognitive load (Straube et al, 2011b). Thus, findings from functional imaging studies and EEG studies might result in different observations.…”

“…Thus, findings from functional imaging studies and EEG studies might result in different observations. However, thus far, designs are only partially comparable and only research using the same designs, and preferentially a within subject paradigm can solve this issue (Straube et al, 2011b).…”

Effects of Intensity of Facial Expressions on Amygdalar Activation Independently of Valence

“…Some studies reported valence-specific effects, particularly threat-specific effects (e.g., Whalen et al, 1998; LeDoux, 2003; Gamer and Büchel, 2009; Inagaki et al, 2012; Furl et al, 2013; Sauer et al, 2014); whereas other studies showed modulations by emotion in general (Yang et al, 2002; Santos et al, 2011) or no emotional effects at all on amygdalar activation (e.g., Fitzgerald et al, 2006; Sato et al, 2010). These discrepancies may be related to multiple factors, such as attention (e.g., Pessoa et al, 2002; Straube et al, 2011a), face habituation (e.g., Breiter et al, 1996; Wright et al, 2001), ambiguity of facial expression (Adams et al, 2003), task condition (e.g., implicit or explicit; e.g., Critchley et al, 2000; Habel et al, 2007) and arousal differences between positive and negative expressions (e.g., Sauer et al, 2014). With regard to the last point, studies that vary arousal of facial expressions in a controlled way (i.e., using positive and negative expressions of matched arousal values) should be highly informative, similar to studies with other kinds of emotional stimuli mentioned above.…”

“…However, happy as compared to angry or fearful expressions are more common in everyday life and therefore, are often perceived less arousing and intense. In this case, the relevance or significance or faces may be reduced, resulting in altering the effects of amygdalar activations (Somerville and Whalen, 2006; Straube et al, 2011a). Therefore, it is still unclear whether these studies (N’Diaye et al, 2009; Mattavelli et al, 2014) used sufficiently strong expressions of happiness or not, with comparable arousal ratings between happy and threat-related expressions.…”

Effortful versus automatic emotional processing in schizophrenia: Insights from a face-vignette task

“…This paradigm is wellsuited for the current study's objectives as the emotional stimuli-faces and vignettes-embody the automatic versus effortful dichotomy described above. Faces capture attention more readily than other objects in one's environment (Ro, Russell, & Lavie, 2001) and information from emotional facial expressions is extracted even more rapidly and automatically (for detailed reviews, see Straube, Mothes-Lasch, & Miltner, 2011;Vuilleumier, 2002). Indeed, Vuilleumier (2002) concludes there is "remarkable convergence of behavioural and neurophysiological evidence suggesting that our brain is equipped with mechanisms for enhancing the detection of and reaction to emotional facial information" (p. 297).…”