What drives prioritized visual processing? A motivational relevance account

Prioritized neural processing of social threats during perceptual decision-making

Emotional signals, notably those signaling threat, benefit from prioritized processing in the human brain. Yet, it remains unclear whether perceptual decisions about the emotional, threat-related aspects of stimuli involve specific or similar neural computations compared to decisions about their non-threatening/non-emotional components. We developed a novel behavioral paradigm in which participants performed two different detection tasks (emotion vs. color) on the same, two-dimensional visual stimuli. First, electroencephalographic (EEG) activity in a cluster of central electrodes reflected the amount of perceptual evidence around 100 ms following stimulus onset, when the decision concerned emotion, not color. Second, participants' choice could be predicted earlier for emotion (240 ms) than for color (380 ms) by the mu (10 Hz) rhythm, which reflects motor preparation. Taken together, these findings indicate that perceptual decisions about threat-signaling dimensions of facial displays are associated with prioritized neural coding in action-related brain regions, supporting the motivational value of socially relevant signals.

Deployment of attention to facial expressions varies as a function of emotional quality-but not in alexithymic individuals

Background

Alexithymia is a risk factor for emotional disorders and is characterized by differences in automatic and controlled emotion processing. The multi-stimulus free-viewing task has been used to detect increased negative and reduced positive attentional biases in depression and anxiety. In the present eye-tracking study, we examined whether lexical emotional priming directs attention toward emotion-congruent facial expressions and whether alexithymia is related to impairments in lexical priming and spontaneous attention deployment during multiple face perception.

Materials and methods

A free-viewing task with happy, fearful, angry, and neutral faces shown simultaneously was administered to 32 alexithymic and 46 non-alexithymic individuals along with measures of negative affect and intelligence. Face presentation was preceded by masked emotion words. Indices of initial orienting and maintenance of attention were analyzed as a function of prime or target category and study group.

Results

Time to first fixation was not affected by prime category or study group. Analysis of fixation duration yielded a three-way interaction. Alexithymic individuals exhibited no prime or target category effect, whereas non-alexithymic individuals showed a main effect of target condition, fixating happy faces longer than neutral and angry faces and fearful faces longer than angry faces.

Discussion

Our results show evidence of attentional biases for positive and fearful social information in non-alexithymic individuals, but not in alexithymic individuals. The lack of spontaneous attentional preference for these social stimuli in alexithymia might contribute to a vulnerability for developing emotional disorders. Our data also suggest that briefly presented emotion words may not facilitate gaze orientation toward emotion-congruent stimuli.

Potentiated early neural responses to fearful faces are not driven by specific face parts

Prioritized processing of fearful compared to neutral faces is reflected in increased amplitudes of components of the event-related potential (ERP). It is unknown whether specific face parts drive these modulations. Here, we investigated the contributions of face parts on ERPs to task-irrelevant fearful and neutral faces using an ERP-dependent facial decoding technique and a large sample of participants (N = 83). Classical ERP analyses showed typical and robust increases of N170 and EPN amplitudes by fearful relative to neutral faces. Facial decoding further showed that the absolute amplitude of these components, as well as the P1, was driven by the low-frequency contrast of specific face parts. However, the difference between fearful and neutral faces was not driven by any specific face part, as supported by Bayesian statistics. Furthermore, there were no correlations between trait anxiety and main effects or interactions. These results suggest that increased N170 and EPN amplitudes to task-irrelevant fearful compared to neutral faces are not driven by specific facial regions but represent a holistic face processing effect.

Animal eMotion, or the emotional evaluation of moving animals

Responding adequately to the behaviour of human and non-human animals in our environment has been crucial for our survival. This is also reflected in our exceptional capacity to detect and interpret biological motion signals. However, even though our emotions have specifically emerged as automatic adaptive responses to such vital stimuli, few studies investigated the influence of biological motion on emotional evaluations. Here, we test how the motion of animals affects emotional judgements by contrasting static animal images and videos. We investigated this question (1) in non-fearful observers across many different animals, and (2) in observers afraid of particular animals across four types of animals, including the feared ones. In line with previous studies, we find an idiosyncratic pattern of evoked emotions across different types of animals. These emotions can be explained to different extents by regression models based on relevant predictor variables (e.g. familiarity, dangerousness). Additionally, our findings show a boosting effect of motion on emotional evaluations across all animals, with an additional increase in (negative) emotions for moving feared animals (except snakes). We discuss implications of our results for experimental and clinical research and applications, highlighting the importance of experiments with dynamic and ecologically valid stimuli.

Interpretation Biases in Pain: Validation of Two New Stimulus Sets

Adults with chronic pain interpret ambiguous information in a pain and illness related fashion. However, limitations have been highlighted with traditional experimental paradigms used to measure interpretation biases. Whilst ambiguous scenarios have been developed to measure interpretation biases in adolescents with pain, no scenario sets exist for use with adults. Therefore, the present study: (i) sought to validate a range of ambiguous scenarios suitable for measuring interpretation biases in adults, whilst also allowing for two response formats (forced-choice and free response); and (ii) investigate paradigm efficacy, by assessing the effects of recent pain experiences on task responding. A novel ambiguous scenarios task was administered to adults (N = 241). Participants were presented with 62 ambiguous scenarios comprising 42 that could be interpreted in a pain/pain-illness or non-pain/non-pain illness manner: and 20 control scenarios. Participants generated their own solutions to each scenario (Word Generation Task), then rated how likely they would be to use two researcher-generated solutions to complete each scenario (Likelihood Ratings Task). Participants also rated their subjective experiences of pain in the last 3 months. Tests of reliability, including inter-rater agreement and internal consistency, produced two ambiguous scenario stimulus sets containing 18 and 20 scenarios, respectively. Further analyses revealed adults who reported more recent pain experiences were more likely to endorse the pain/pain-illness solutions in the Likelihood Ratings Task. This study provides two new stimulus sets for use with adults (including control items) in pain research and/or interventions. Results also provide evidence for a negative endorsement bias in adults.

Developmental differences in the visual processing of emotionally ambiguous neutral faces based on perceived valence

The aim of the present research was to assess age-related differences in how children and adults interpret and visually process emotionally ambiguous neutral faces. Children and adults provided neutral child faces with valence and arousal ratings while eye movements were recorded. Consistent with previous research, children and adults both interpreted the neutral faces as negatively valenced. Both age groups showed fewer fixations to the eye region when they rated the faces as positive. However, adults fixated more on the eye region when they rated the faces as negative whereas children fixated more on the eye region when they rated the faces as neutral. This finding may suggest that children strategically allocate attentional resources to the eye region when processing emotionally ambiguous faces to gather critical affective information. These findings have implications for the utilization of neutral faces as an experimental control condition and serve as the foundation for future research on the development of mechanisms that underlie the interpretation of emotionally ambiguous faces.

Psychological mechanisms and functions of 5-HT and SSRIs in potential therapeutic change: Lessons from the serotonergic modulation of action selection, learning, affect, and social cognition

Uncertainty regarding which psychological mechanisms are fundamental in mediating SSRI treatment outcomes and wide-ranging variability in their efficacy has raised more questions than it has solved. Since subjective mood states are an abstract scientific construct, only available through self-report in humans, and likely involving input from multiple top-down and bottom-up signals, it has been difficult to model at what level SSRIs interact with this process. Converging translational evidence indicates a role for serotonin in modulating context-dependent parameters of action selection, affect, and social cognition; and concurrently supporting learning mechanisms, which promote adaptability and behavioural flexibility. We examine the theoretical basis, ecological validity, and interaction of these constructs and how they may or may not exert a clinical benefit. Specifically, we bridge crucial gaps between disparate lines of research, particularly findings from animal models and human clinical trials, which often seem to present irreconcilable differences. In determining how SSRIs exert their effects, our approach examines the endogenous functions of 5-HT neurons, how 5-HT manipulations affect behaviour in different contexts, and how their therapeutic effects may be exerted in humans - which may illuminate issues of translational models, hierarchical mechanisms, idiographic variables, and social cognition.

Can compassion, happiness and sympathetic concern be differentiated on the basis of facial expression?

Recent research has demonstrated the importance of positive emotions, and especially compassion, for well-being. Via two investigations, we set out to determine if facial expressions of happiness, "kind" compassion and sympathetic concern can be distinguished, given limitations of previous research. In investigation one, prototypes of the three expressions were analysed for similarities and differences using the facial action coding system (FACS) by two certified independent coders. Results established that each expression comprised distinct FACS units. Thus, in investigation 2, a new photographic stimulus set was developed using a gender/racially balanced group of actors to pose these expressions of "kind" compassion, happiness, sympathetic concern, and the face in a relaxed/neutral pose. 75 participants were then asked to name the FACS generated expressions using not only forced categorical quantitative ratings but, importantly, free response. Results revealed that kind compassionate facial expressions: (i) engendered words associated with contented and affiliative emotions (although, interestingly, not the word "kind"); (ii) were labelled as compassionate significantly more often than any of the other emotional expressions; but (iii) in common with happiness expressions, engendered happiness word groupings and ratings. Findings have implications for understandings of positive emotions, including specificity of expressions and their veridicality.

Uncovering electrophysiological and vascular signatures of implicit emotional prosody

The capability of differentiating between various emotional states in speech displays a crucial prerequisite for successful social interactions. The aim of the present study was to investigate neural processes underlying this differentiating ability by applying a simultaneous neuroscientific approach in order to gain both electrophysiological (via electroencephalography, EEG) and vascular (via functional near-infrared-spectroscopy, fNIRS) responses. Pseudowords conforming to angry, happy, and neutral prosody were presented acoustically to participants using a passive listening paradigm in order to capture implicit mechanisms of emotional prosody processing. Event-related brain potentials (ERPs) revealed a larger P200 and an increased late positive potential (LPP) for happy prosody as well as larger negativities for angry and neutral prosody compared to happy prosody around 500 ms. FNIRS results showed increased activations for angry prosody at right fronto-temporal areas. Correlation between negativity in the EEG and activation in fNIRS for angry prosody suggests analogous underlying processes resembling a negativity bias. Overall, results indicate that mechanisms of emotional and phonological encoding (P200), emotional evaluation (increased negativities) as well as emotional arousal and relevance (LPP) are present during implicit processing of emotional prosody.