EmoMadrid: An emotional pictures database for affect research

An extremely fast neural mechanism to detect emotional visual stimuli: A two-experiment study

Defining the brain mechanisms underlying initial emotional evaluation is a key but unexplored clue to understanding affective processing. Event-related potentials (ERPs), especially suited for investigating this issue, were recorded in two experiments (n = 36 and n = 35). We presented emotionally negative (spiders) and neutral (wheels) silhouettes homogenized regarding their visual parameters. In Experiment 1, stimuli appeared at fixation or in the periphery (200 trials per condition and location), the former eliciting a N40 (39 milliseconds) and a P80 (or C1: 80 milliseconds) component, and the latter only a P80. In Experiment 2, stimuli were presented only at fixation (500 trials per condition). Again, an N40 (45 milliseconds) was observed, followed by a P100 (or P1: 105 milliseconds). Analyses revealed significantly greater N40-C1P1 peak-to-peak amplitudes for spiders in both experiments, and ANCOVAs showed that these effects were not explained by C1P1 alone, but that processes underlying N40 significantly contributed. Source analyses pointed to V1 as an N40 focus (more clearly in Experiment 2). Sources for C1P1 included V1 (P80) and V2/LOC (P80 and P100). These results and their timing point to low-order structures (such as visual thalamic nuclei or superior colliculi) or the visual cortex itself, as candidates for initial evaluation structures.

The standardization of a new Explicit Pornographic Picture Set (EPPS)

Pictures with affective content have been extensively used in scientific studies of emotion and sexuality. However, only a few standardized picture sets have been developed that offer explicit images, with most lacking pornographic pictures depicting diverse sexual practices. This study aimed to fill this gap through developing a standardized affective set of diverse pornographic pictures (masturbation, oral sex, vaginal sex, anal sex, group sex, paraphilia) of same-sex and opposite-sex content, offering dimensional affective ratings of valence, arousal, and dominance, as well as co-elicited discrete emotions (disgust, moral and ethical acceptance). In total, 192 pornographic pictures acquired from online pornography platforms and 24 control IAPS images have been rated by 319 participants (Mage = 22.66, SDage = 4.66) with self-reported same- and opposite-sex sexual attraction. Stimuli were representative of the entire affective space, including positively and negatively perceived pictures. Participants showed differential affective perception of pornographic pictures according to gender and sexual attraction. Differences in affective ratings related to participants' gender and sexual attraction, as well as stimuli content (depicted sexual practices and sexes). From the stimuli set, researchers can select explicit pornographic pictures based on the obtained affective ratings and technical parameters (i.e., pixel size, luminosity, color space, contrast, chromatic complexity, spatial frequency, entropy). The stimuli set may be considered a valid tool of diverse explicit pornographic pictures covering the affective space, in particular, for women and men with same- and opposite-sex sexual attraction. This new explicit pornographic picture set (EPPS) is available to the scientific community for non-commercial use.

Validation of the open biological negative image set for a Portuguese population: Comparing Japanese and Portuguese samples and an exploration of low-order visual properties of the stimuli

Recently, Shirai and Watanabe Royal Society Open Science, 9(1), 211128 (2022) developed OBNIS (Open Biological Negative Image Set), a comprehensive database containing images (primarily animals but also fruits, mushrooms, and vegetables) that visually elicit disgust, fear, or neither. OBNIS was initially validated for a Japanese population. In this article, we validated the color version of OBNIS for a Portuguese population. In study 1, the methodology of the original article was used. This allowed direct comparisons between the Portuguese and Japanese populations. Aside from a few emotional classification mismatches between disgust, fear, or neither-related images, we found that arousal and valence relate distinctively in both populations. In contrast to the Japanese sample, the Portuguese reported increased arousal for more positive valenced stimuli, suggesting that OBNIS images elicit positive emotions in the Portuguese population. These results showed important cross-cultural differences regarding OBNIS. In study 2, a methodological change was introduced: instead of the three classification options used originally (fear, disgust, or neither), six basic emotions were used (fear, disgust, sadness, surprise, anger, happiness), and a "neither" option, to confirm whether some of the originally "neither-related" images are associated with positive emotions (happiness). Additionally, the low-order visual properties of images (luminosity, contrast, chromatic complexity, and spatial frequency distribution) were explored due to their important role in emotion-related research. A fourth image group associated with happiness was found in the Portuguese sample. Moreover, image groups present differences regarding the low-order visual characteristics, which are correlated with arousal and valence ratings, highlighting the importance of controlling such characteristics in emotion-related research.

Postural control in emotional states: An effect of biofeedback

BACKGROUND

Emotional states in the short term and affective impairments, such as anxiety and depression in the long run, can have a significant impact on postural control. Individuals with these conditions often struggle with maintaining balance during emotionally charged situations, which can increase their risk of falls and injuries. Biofeedback has been proposed as a potential intervention to improve postural control during emotional induction.

RESEARCH QUESTION

How do emotional stimuli affect postural control performance in the presence of real-time postural feedback?

METHODS

Forty-two participants took part in the study. The visual stimuli used in the experiment to induce emotions of various valence in the subjects were video clips, containing a series of pictures (24 positive, 24 neutral and 24 negative pictures). During the experiment, participants were required to maintain balance standing on a force platform while watching the videos on a computer screen. For each subject, three sessions of 480 s were generated, each of which included two conditions: with and without biofeedback (a target on the screen indicating the subject's position relative to the center of pressure (CoP).

RESULTS

The No Feedback condition provoked a higher medial-lateral and anterior-posterior sway, but lower velocity of CoP than the Feedback condition. We did not find any effect of the valence of emotional videos on indicators of postural control in No Feedback condition. However, both negative and positive videos provoked a lower velocity of CoP in comparison to neutral videos in the Feedback condition.

SIGNIFICANCE

Changes observed in postural control during the Feedback condition in the presence of emotional stimuli (both negative and positive) could be explained by the shift in attention from the task of maintaining posture to the emotional videos. The results of this study have important implications for clinicians involved in postural training and rehabilitation.

The relationship of action, affect, and metacognition in functional seizures

INTRODUCTION

Metacognition provides a lens through which individuals experience, interpret, and respond to their affective states and behavior; it might thus influence complex neuropsychiatric conditions such as functional seizures - events characterized by states of heightened affective arousal and the disinhibition of prepotent behavior. In this pilot study, we aimed to establish a better understanding of the role of metacognition in functional seizures and its relationship to affective arousal and behavioral disinhibition (i.e., problems in suppressing prepared behavior). We hypothesized that affective arousal is related to higher behavioral disinhibition as well as slower reaction times, that affect and action (performing vs. not performing a movement) are related to memory and metacognition, and that metacognition is related to illness characteristics.

METHODS

We used a combination of an emotional go/no-go and a metacognitive recognition task with affectively valenced and neutral images in 18 patients with functional seizures. We compared markers of behavioral inhibition as well as indices for memory and metacognitive performance between affective (vs. neutral) and action/go (vs. inhibition/no-go) conditions.

RESULTS

Contrary to our hypothesis, behavioral disinhibition was not different between conditions. However, we found slower reaction times for affectively valenced stimuli. Memory performance and metacognition were better for affectively valenced pictures and for pictures used in go trials (i.e., associated with action/performing the movement). Illness factors (illness duration, seizure frequency, levels of self-reported anxiety) were correlated with aspects of metacognition.

CONCLUSIONS

This pilot study offers first insights into alterations in metacognition related to action and affect in patients with functional seizures; specifically, that affectively valenced stimuli and active engagement are related to enhanced memory and metacognition. This relationship was also found with respect to illness factors. These results provide insight into potentially underlying pathomechanisms, although the lack of a control group limits evaluating the specificity of these findings.

More than a feeling: Effects of competitive asymmetry on human emotions

Competitive interactions have important effects on human emotions. Both victory and defeat can evoke a wide range of emotional reactions, including joy, pride, anger, fear, sadness and shame. However, little is known about what determines this variety of contestants' affective responses. Therefore, the purpose of this study was to evaluate the effects of competitive asymmetry, a common and ecologically relevant feature of animal conflicts, on human emotional responses to winning or losing a contest. To test this hypothesis, we conducted two experiments, the first with high school students (n = 331) and the second with young athletes (n = 73), in which we manipulated the outcomes of successive matches in a non-athletic competition. Thus, by inducing the competitors' scores, ranging from closer to more decisive outcomes, we were able to define the degree of competitive asymmetry in victory and defeat conditions. We then assessed participants' emotional responses to a set of affective stimuli. In the defeat condition, we found in both studies an increase in the occurrence of anger and fear due to more symmetric contests. There were also more frequent reports of shame following more decisive defeats (Experiment 1) and of pride following closer victories (Experiment 2), which were seen neither for sadness nor joy in any of the studies. Supporting our hypothesis, emotional reactions triggered by asymmetries among contestants were consistent with the behavioral patterns commonly seen in symmetric and asymmetric animal conflict, such as dominance/aggressive and defensive/escape behaviors.

Affective norms for emotional ambiguity in valence, origin, and activation spaces

We introduce the first tool to measure the emotional ambiguity on three bivariate spaces: valence (dimensions of positivity and negativity); origin (automaticity and reflectiveness); and activation (subjective significance and arousal). Our database consists of 2650 word stimuli, assessed by 1380 participants in total with the usage of Self-Assessment Manikin scales for each dimension. We show that the ambiguity of valence, origin, and activation may be successfully perceived and reported in a behavioral procedure. The study has allowed us to compute characteristics of each word for every emotional dimension, thus providing the category of intensity of ambiguity (low, moderate, or high). We also studied the curvilinear relationships between the dimensions. Possible usage, specifics, and limitations of our database are discussed.

Development and validation of a highly dynamic and reusable picture-based scale: A new affective measurement tool

Emotion measurement is crucial to conducting emotion research. Numerous studies have extensively employed textual scales for psychological and organizational behavior research. However, emotions are transient states of organisms with relatively short duration, some insurmountable limitations of textual scales have been reported, including low reliability for single measurement or susceptibility to learning effects for multiple repeated use. In the present article, we introduce the Highly Dynamic and Reusable Picture-based Scale (HDRPS), which was randomly generated based on 3,386 realistic, high-quality photographs that are divided into five categories (people, animals, plants, objects, and scenes). Affective ratings of the photographs were gathered from 14 experts and 209 professional judges. The HDRPS was validated using the Self-Assessment Manikin and the PANAS by 751 participants. With an accuracy of 89.73%, this new tool allows researchers to measure individual emotions continuously for their research. The non-commercial use of the HDRPS system can be freely accessible by request at http://syy.imagesoft.cc:8989/Pictures.7z. HDRPS is used for non-commercial academic research only. As some of the images are collected through the open network, it is difficult to trace the source, so please contact the author if there are any copyright issues.

The role of sleep and wakefulness in the recognition of emotional pictures

Sleep has a beneficial effect on memory consolidation. However, its role in emotional memory is currently debated. Here, we investigate the role of sleep and a similar period of wakefulness on the recognition of emotional pictures and subjective emotional reactivity. Forty participants without any major physical, neurological or psychological condition were randomly assigned to the Sleep First Group or Wake First Group. The two groups underwent the encoding phase of an emotional images task with negative and neutral pictures at either 09:00 hours (Wake First Group) or 21:00 hours (Sleep First Group). Then participants performed an immediate recognition test (T1), and two delayed tests 12 hr (T2) and 24 hr (T3) later. Perceived arousal and valence levels were collected for each picture. Sleep parameters were recorded at participants' homes with a portable device. No differences were observed at T1, whereas at T2 the Sleep First Group showed a higher memory performance than the Wake First Group. At T3, performance decreased in the Sleep First Group (who spent the previous 12 hr awake), but not in the Wake First Group (who slept during the previous 12 hr). Overall, negative images were remembered better than neutral ones. We also observed a positive association between memory performance for negative items at the immediate test and the percentage of rapid eye movement sleep the night before the encoding. Our data confirm that negative information is remembered better over time than neutral information, and that sleep benefits the retention of declarative information. However, sleep seems not to preferentially improve emotional memory, although it may affect the encoding of negative information.

Graphene e-tattoos for unobstructive ambulatory electrodermal activity sensing on the palm enabled by heterogeneous serpentine ribbons

Electrodermal activity (EDA) is a popular index of mental stress. State-of-the-art EDA sensors suffer from obstructiveness on the palm or low signal fidelity off the palm. Our previous invention of sub-micron-thin imperceptible graphene e-tattoos (GET) is ideal for unobstructive EDA sensing on the palm. However, robust electrical connection between ultrathin devices and rigid circuit boards is a long missing component for ambulatory use. To minimize the well-known strain concentration at their interfaces, we propose heterogeneous serpentine ribbons (HSPR), which refer to a GET serpentine partially overlapping with a gold serpentine without added adhesive. A fifty-fold strain reduction in HSPR vs. heterogeneous straight ribbons (HSTR) has been discovered and understood. The combination of HSPR and a soft interlayer between the GET and an EDA wristband enabled ambulatory EDA monitoring on the palm in free-living conditions. A newly developed EDA event selection policy leveraging unbiased selection of phasic events validated our GET EDA sensor against gold standards.

Exogenous Attention to Emotional Stimuli Presenting Realistic (3D) Looming Motion

Previous research shows that dynamic stimuli, on the one hand, and emotional stimuli, on the other, capture exogenous attention due to their biological relevance. Through neural (ERPs) and behavioral measures (reaction times and errors), the present study explored the combined effect of looming motion and emotional content on attentional capture. To this end, 3D-recreated static and dynamic animals assessed as emotional (positive or negative) or neutral were presented as distractors while 71 volunteers performed a line orientation task. We observed a two-phase effect: firstly (before 300 ms), early components of ERPs (P1p and N2po) showed enhanced exogenous attentional capture by looming positive distractors and static threatening animals. Thereafter, dynamic and static threatening distractors received enhanced endogenous attention as revealed by both late ERP activity (LPC) and behavioral (errors) responses. These effects are likely explained by both the emotional valence and the distance of the stimulus at each moment.

Real-time fMRI neurofeedback compared to cognitive behavioral therapy in a pilot study for the treatment of mild and moderate depression

Real-time functional magnetic resonance imaging (rt-fMRI) neurofeedback was found to reduce depressive symptoms. However, no direct comparison of drug-free patients with an active psychotherapy control group is available. The present study compared rt-fMRI neurofeedback with cognitive behavioral therapy, as the standard treatment in patients declining anti-depressants. Twenty adult, drug-free patients with mild or moderate depression were non-randomly assigned either to a course of eight half-hour sessions of neurofeedback targeting the left medial prefrontal cortex (N = 12) or to a 16-session course of cognitive behavioral therapy (N = 8). Montgomery-Asberg Depression Rating Scale was introduced at baseline, mid-treatment, and end-treatment points. In each group, 8 patients each remained in the study to a mid-treatment evaluation and 6 patients each to the study end-point. ANOVA revealed a depression reduction with a significant effect of Time (F(3,6) = 19.0, p < 0.001, η² = 0.76). A trend to greater improvement in the cognitive behavioral therapy group compared to neurofeedback emerged (Group × Time; p = 0.078). Percent signal change in the region of interest between up- and down-regulation conditions was significantly correlated with session number (Pearson's r = 0.85, p < 0.001) indicating a learning effect. As limitations, small sample size could lead to insufficient power and non-random allocation to selection bias. Both neurofeedback and cognitive behavioral therapy improved mild and moderate depression. Neurofeedback was not superior to cognitive behavioral therapy. Noteworthy, the neurofeedback training course was associated with continuous improvement in the self-regulation skill, without plateau. This study delivers data to plan clinical trials comparing neurofeedback with cognitive behavioral interventions.

Musical emotions affect memory for emotional pictures

Music is widely known for its ability to evoke emotions. However, assessing specific music-evoked emotions other than through verbal self-reports has proven difficult. In the present study, we explored whether mood-congruency effects could be used as indirect measures of specific music-evoked emotions. First, participants listened to 15 music excerpts chosen to induce different emotions; after each excerpt, they were required to look at four different pictures. The pictures could either: (1) convey an emotion congruent with that conveyed by the music (i.e., congruent pictures); (2) convey a different emotion than that of the music, or convey no emotion (i.e., incongruent pictures). Second, participants completed a recognition task that included new pictures as well as already seen congruent and incongruent pictures. From previous findings about mood-congruency effects, we hypothesized that if music evokes a given emotion, this would facilitate memorization of pictures that convey the same emotion. Results revealed that accuracy in the recognition task was indeed higher for emotionally congruent pictures than for emotionally incongruent ones. The results suggest that music-evoked emotions have an influence on subsequent cognitive processing of emotional stimuli, suggesting a role of mood-congruency based recall tasks as non-verbal methods for the identification of specific music-evoked emotions.

Suppression of alpha-band power underlies exogenous attention to emotional distractors

Alpha-band oscillations (8-14 Hz) are essential for attention and perception processes by facilitating the selection of relevant information. Directing visuospatial endogenous (voluntary) attention to a given location consistently results in a power suppression of alpha activity over occipito-parietal areas contralateral to the attended visual field. In contrast, the neural oscillatory dynamics underlying the involuntary capture of attention, or exogenous attention, are currently under debate. By exploiting the inherent capacity of emotionally salient visual stimuli to capture attention, we aimed to investigate whether exogenous attention is characterized by either a reduction or an increase in alpha-band activity. Electroencephalographic activity was recorded while participants completed a Posner visuospatial cueing task, in which a lateralized image with either positive, negative, or neutral emotional content competed with a target stimulus presented in the opposite hemifield. Compared with trials with no distractors, alpha power was reduced over occipital regions contralateral to distracting images. This reduction of alpha activity turned out to be functionally relevant, as it correlated with impaired behavioral performance on the ongoing task and was enhanced for distractors with negative valence. Taken together, our results demonstrate that visuospatial exogenous attention is characterized by a suppression of alpha-band activity contralateral to distractor location, similar to the oscillatory underpinnings of endogenous attention. Further, these results highlight the key role of exogenous attention as an adaptive mechanism for the efficient detection of biologically salient stimuli.

Fast Unconscious Processing of Emotional Stimuli in Early Stages of the Visual Cortex

Several cortical and subcortical brain areas have been reported to be sensitive to the emotional content of subliminal stimuli. However, the timing of these activations remains unclear. Our scope was to detect the earliest cortical traces of emotional unconscious processing of visual stimuli by recording event-related potentials (ERPs) from 43 participants. Subliminal spiders (emotional) and wheels (neutral), sharing similar low-level visual parameters, were presented at two different locations (fixation and periphery). The differential (peak-to-peak) amplitude from CP1 (77 ms from stimulus onset) to C2 (100 ms), two early visual ERP components originated in V1/V2 according to source localization analyses, was analyzed via Bayesian and traditional frequentist analyses. Spiders elicited greater CP1–C2 amplitudes than wheels when presented at fixation. This fast effect of subliminal stimulation—not reported previously to the best of our knowledge—has implications in several debates: 1) The amygdala cannot be mediating these effects, 2) latency of other evaluative structures recently proposed, such as the visual thalamus, is compatible with these results, 3) the absence of peripheral stimuli effects points to a relevant role of the parvocellular visual system in unconscious processing.

Exploration of Exogenous Attention to Disgust and Fear Pictures with Different Spatial Frequencies Through Event-related Potentials

The study of the effects of fear and disgust on the capture of automatic attention is gaining interest. Most findings reveal a more efficient capture of exogenous attention by disgust than by fear stimuli, although the underlying mechanisms are not completely understood. The manipulation of their spatial frequency may provide new insight that may contribute to clarify this issue. The present study aimed to explore differential processing of disgust and fear scenes containing only low spatial frequencies (LSF) or all spatial frequencies (intact) presented as distractors in an exogenous attention task. Event-related potentials (ERPs) and behavioral responses were recorded as dependent variables from forty participants (29 women). The results showed that disgust and fear distractors captured exogenous attention equally early, as indicated by the augmented amplitude of the N2p, and later disgust distractors are the ones eliciting the highest amplitude of the LPP component. While in an initial stage, both stimuli seem to have similar preferential access to further processing allowing fast responding in both cases, disgust is more deeply processed at a later stage probably facilitating its examination. These findings suggest that exploring the temporal course of processing is relevant for the understanding of the differential capture of exogenous attention by disgust and fear distractors.

Affective Computing on Machine Learning-Based Emotion Recognition Using a Self-Made EEG Device

In this research, we develop an affective computing method based on machine learning for emotion recognition using a wireless protocol and a wearable electroencephalography (EEG) custom-designed device. The system collects EEG signals using an eight-electrode placement on the scalp; two of these electrodes were placed in the frontal lobe, and the other six electrodes were placed in the temporal lobe. We performed experiments on eight subjects while they watched emotive videos. Six entropy measures were employed for extracting suitable features from the EEG signals. Next, we evaluated our proposed models using three popular classifiers: a support vector machine (SVM), multi-layer perceptron (MLP), and one-dimensional convolutional neural network (1D-CNN) for emotion classification; both subject-dependent and subject-independent strategies were used. Our experiment results showed that the highest average accuracies achieved in the subject-dependent and subject-independent cases were 85.81% and 78.52%, respectively; these accuracies were achieved using a combination of the sample entropy measure and 1D-CNN. Moreover, our study investigates the T8 position (above the right ear) in the temporal lobe as the most critical channel among the proposed measurement positions for emotion classification through electrode selection. Our results prove the feasibility and efficiency of our proposed EEG-based affective computing method for emotion recognition in real-world applications.

Photo Sequences of Varying Emotion: Optimization with a Valence-Arousal Annotated Dataset

Synthesizing photo products such as photo strips and slideshows using a database of images is a time-consuming and tedious process that requires significant manual work. To overcome this limitation, we developed a method that automatically synthesizes photo sequences based on several design parameters. Our method considers the valence and arousal ratings of images in conjunction with parameters related to both the visual consistency of the synthesized photo sequence and the progression of valence and arousal throughout the photo sequence. Our method encodes valence, arousal, and visual consistency parameters as cost terms into a total cost function while applying a Markov chain Monte Carlo optimization techniques called simulated annealing to synthesize the photo sequence based on user-defined target objectives in a few seconds. As our method was developed for the synthesis of photo sequences using the valence-arousal emotional model, a user study was conducted to evaluate the efficacy of the synthesized photo sequences in triggering valence-arousal ratings as expected. Our results indicate that the proposed method synthesizes photo sequences in which valence and arousal dimensions are perceived as expected by participants; however, valence may be more appropriately perceived than arousal.

Emotion elicitation during music listening: Subjective self-reports, facial expression, and autonomic reactivity

The use of music as emotional stimuli in experimental studies has grown in recent years. However, prior studies have mainly focused on self-reports and central measures, with a few works exploring the time course of psychophysiological correlates. Moreover, most of the previous research has been carried out either from the dimensional or categorical model but not combining both approaches to emotions. This study aimed to investigate subjective and physiological correlates of emotion elicitation through music, following the three-dimensional and the discrete emotion model. A sample of 50 healthy volunteers (25 women) took part in this experiment by listening to 42 film music excerpts (14 pleasant, 14 unpleasant, 14 neutral) presented during 8 s, while peripheral measures were continuously recorded. After music offset, affective dimensions (valence, energy arousal, and tension arousal) as well as discrete emotions (happiness, sadness, tenderness, fear, and anger) were collected using a 9-point scale. Results showed an effect of the music category on subjective and psychophysiological measures. In peripheral physiology, greater electrodermal activity, heart rate acceleration, and zygomatic responses, besides lower corrugator amplitude, were observed for pleasant excerpts in comparison to neutral and unpleasant music, from 2 s after stimulus onset until the end of its duration. Overall, our results add evidence for the efficacy of standardized film music excerpts to evoke powerful emotions in laboratory settings; thus, opening a path to explore interventions based on music in pathologies with underlying emotion deregulatory processes.

In exogenous attention, time is the clue: Brain and heart interactions to survive threatening stimuli

The capture of exogenous attention by negative stimuli has been interpreted as adaptive for survival in a diverse and changing environment. In the present paper, we investigate the neural responses towards two discrete negative emotions with different biological meanings, disgust and fear, and its potential relationships with heart rate variability (HRV) as an index of emotional regulation. With that aim, 30 participants performed a digit categorization task while fear, disgust and neutral distractor pictures were presented. Resting HRV at baseline, behavioral responses, and event-related potentials were recorded. Whereas P1 amplitudes were highest to fear distractors, the disgust stimulation led to augmented P2 amplitudes compared to the rest of distractors. Interestingly, increased N2 amplitudes were also found to disgust distractors, but only in high HRV participants. Neural source estimation data point to the involvement of the insula in this exogenous attentional response to disgust. Additionally, disgust distractors provoked longer reaction times than fear and neutral distractors in the high HRV group. Present findings are interpreted in evolutionary terms suggesting that exogenous attention is captured by negative stimuli following a different time course for fear and disgust. Possible HRV influences on neural mechanisms underlying exogenous attention are discussed considering the potential important role of this variable in emotional regulation processes.

Remote Digital Measurement of Facial and Vocal Markers of Major Depressive Disorder Severity and Treatment Response: A Pilot Study

Objectives: Multiple machine learning-based visual and auditory digital markers have demonstrated associations between major depressive disorder (MDD) status and severity. The current study examines if such measurements can quantify response to antidepressant treatment (ADT) with selective serotonin reuptake inhibitors (SSRIs) and serotonin-norepinephrine uptake inhibitors (SNRIs). Methods: Visual and auditory markers were acquired through an automated smartphone task that measures facial, vocal, and head movement characteristics across 4 weeks of treatment (with time points at baseline, 2 weeks, and 4 weeks) on ADT (n = 18). MDD diagnosis was confirmed using the Mini-International Neuropsychiatric Interview (MINI), and the Montgomery-Åsberg Depression Rating Scale (MADRS) was collected concordantly to assess changes in MDD severity. Results: Patient responses to ADT demonstrated clinically and statistically significant changes in the MADRS [F (2, 34) = 51.62, p < 0.0001]. Additionally, patients demonstrated significant increases in multiple digital markers including facial expressivity, head movement, and amount of speech. Finally, patients demonstrated significantly decreased frequency of fear and anger facial expressions. Conclusion: Digital markers associated with MDD demonstrate validity as measures of treatment response.

MATTER in emotion research: Spanish standardization of an affective image set

Pictures with affective content have been widely used in the scientific study of emotions, from two main perspectives: on the one hand, dimensional theories claiming that affective experiences can be described according to a few fundamental dimensions such as valence and arousal, and on the other hand, discrete-category theories proposing the presence of a number of basic and universal emotions. Although it has been demonstrated that these two approaches are not mutually exclusive, the existing standardized affective picture databases have been created from the dimensional perspective, which has led to important gaps for research focused on discrete emotions. The present work introduces MATTER, a new database comprising 540 pictures depicting disgusting, fearful, neutral, erotic, mirthful and incongruent content, which provides normative values (total N = 368, mean = 120.47 ratings/picture) in valence and arousal dimensions, as well as in discrete affective (disgust, fear, erotica and mirth) and cognitive (incongruence and interest) features. A tentative classification into discrete categories is presented, and the physical properties of each picture are reported. Our findings suggest that MATTER constitutes a modern and suitable set of affective images including, for the first time, both mirth- and incongruence-related pictures. Additionally, it will enable the examination of affective and cognitive processes in fear/disgust and humor/incongruence fields.

Realistic (3D) looming of emotional visual stimuli: Attentional effects at neural and behavioral levels

Previous research shows that endogenous attention (the controlled selection of certain aspects of our environment) is enhanced toward emotional stimuli due to its biological relevance. Although looming affective stimuli such as threat seem even more critical for survival, little is known about their effect on endogenous attention. Here, we recorded neural (event-related potentials, ERPs) and behavioral responses (errors and reaction times) to explore the combined effect of emotion and looming motion. 3D-recreated static and moving animals assessed as emotionally positive, negative, and neutral, were presented to participants (n = 71), who performed an indirect categorization task (vertebrate vs. invertebrate). Behavioral results showed better task performance, as reflected by lower number of errors and reaction times, in response to threatening stimuli. Neural indices revealed significant early (P1p, 150 milliseconds), intermediate (P2p, 240), and late (LPP, 450) effects, the latter being more intensely associated with behavior, as revealed by regression analyses. In general, neural indexes of attention to both static and dynamic stimuli showed a positivity offset in early stages and a negativity bias in subsequent phases. However, and importantly, the progressive inclusion of negative stimuli in the attentional focus is produced earlier in the case of dynamic (at P2p latency) than in static versions (at LPP). These results point to an enhancement of attention, particularly in temporal terms, toward stimuli combining motion and biological significance.

Understanding the capture of exogenous attention by disgusting and fearful stimuli: The role of interoceptive accuracy

The aim of the study was to explore the role of interoceptive accuracy (IA) on exogenous attention to disgusting and fearful distractors of a main concurrent task. Participants were thirty university students previously identified as high (N = 16) or normal IA according their performance in a heartbeat detection task. Event-related potentials and behavioural responses were recorded. The results showed that disgusting stimuli capture exogenous attention in a first stage as reflected by the augmented amplitude of the P100 component of the ERPs in high IA participants. Fearful distractors may capture attention in a later moment in all participants as revealed by a marginally significant effect on the amplitude of N200. At behavioural level, disgusting distractors provoked a higher number of errors than neutral in normal IA participants. The time course of the effect of disgust and fearful eliciting distractors on exogenous attention appeared to depend on the individual characteristic of participants.

Retinotopy of emotion: Perception of negatively valenced stimuli presented at different spatial locations as revealed by event-related potentials

Scarce previous data on how the location where an emotional stimulus appears in the visual scene modulates its perception suggest that, for functional reasons, a perceptual advantage may exist, vertically, for stimuli presented at the lower visual field (LoVF) and, horizontally, for stimuli presented at the left visual field (LeVF). However, this issue has been explored through a limited number of spatial locations, usually in a single spatial dimension (e.g., horizontal) and invariant eccentricities. Event-related potentials (ERPs) were recorded from 39 participants perceiving brief neutral (wheels) and emotional stimuli (spiders) presented at 17 different locations, one foveal and 16 at different peripheral coordinates. As a secondary scope, we explored the role of the magnocellular (M) and the parvocellular (P) visual pathways by presenting an isoluminant/heterochromatic (P-biased) and a heteroluminant/isochromatic version (M-biased) of each stimulus. Emo > Neu effects were observed in PN1 (120 ms) for stimuli located at fovea, and in PN2 (215 ms) for stimuli located both at fovea and diverse peripheral regions. A factorial approach to these effects further revealed that: (a) emotional stimuli presented in the periphery are efficiently perceived, without evident decrease from para- to perifovea; (b) peripheral Emo > Neu effects are reflected 95 ms later than foveal Emo > Neu effects in ERPs; (c) LoVF is more involved than UVF in these effects; (d) our data fail to support the LeVF advantage previously reported, and (e) Emo > Neu effects were significant for both M and P stimuli.

Investigating Emotional Similarity: A Comment on Riberto, Pobric, and Talmi (2019)

A recent review of the neuroimaging literature on emotional similarity brought to light some of the drawbacks of the latest studies. The authors discussed important methodological considerations for future work in this field, which predominantly involved stimulus selection. In general, we feel that their suggestions are valuable, but we hold that, depending on the specific scientific question(s) under investigation (e.g., individual differences), some of the suggestions may not meaningfully contribute to the scope of the study and might even introduce artificial constraints that could reduce the researchers' ability to discover effects of interest. Here we indicate one way to potentially circumvent such stimulus-related issues in neuroimaging studies and furthermore present a few scenarios in which additional controlling of the stimulus set may not be necessary or possible when investigating individual differences. This commentary serves to supplement the important methodological points raised by the authors by providing a caveat in potentially applying such points to all future experiments investigating emotional similarity.

Enhanced response inhibition and reduced midfrontal theta activity in experienced Vipassana meditators

Response inhibition - the ability to suppress inappropriate thoughts and actions - is a fundamental aspect of cognitive control. Recent research suggests that mental training by meditation may improve cognitive control. Yet, it is still unclear if and how, at the neural level, long-term meditation practice may affect (emotional) response inhibition. The present study aimed to address this outstanding question, and used an emotional Go/Nogo task and electroencephalography (EEG) to examine possible differences in behavioral and electrophysiological indices of response inhibition between Vipassana meditators and an experience-matched active control group (athletes). Behaviorally, meditators made significantly less errors than controls on the emotional Go/Nogo task, independent of the emotional context, while being equally fast. This improvement in response inhibition at the behavioral level was accompanied by a decrease in midfrontal theta activity in Nogo vs. Go trials in the meditators compared to controls. Yet, no changes in ERP indices of response inhibition, as indexed by the amplitude of the N2 and P3 components, were observed. Finally, the meditators subjectively evaluated the emotional pictures lower in valence and arousal. Collectively, these results suggest that meditation may improve response inhibition and control over emotional reactivity.