Threat directionality modulates defensive reactions in humans: cardiac and electrodermal responses.

Features of threatening cues and the associated context influence the perceived imminence of threat and the defensive responses evoked. To provide additional knowledge about how the directionality of a threat (i.e. directed-towards or away from the viewer) might impact defensive responses in humans, participants were shown pictures of a man carrying a gun (threat) or nonlethal object (neutral) directed-away from or towards the participant. Cardiac and electrodermal responses were collected. Compared to neutral images, threatening images depicting a gun directed-towards the participant induced sustained bradycardia and an increased electrodermal response, interpreted as immobility under attack. This defensive immobility reaction is evoked by high perceived threat and inescapable situations and indicates intense action preparation. Pictures of guns directed-away from the participant induced shorter bradycardia and no significant modulation of the electrodermal response compared to neutral pictures, which might be consistent with the perception of a less threatening situation. The results show that the directionality of threat stimuli is a key factor that prompts different patterns of defensive responses.

Machine Learning Algorithms for Activity-Intensity Recognition Using Accelerometer Data.

In pervasive healthcare monitoring, activity recognition is critical information for adequate management of the patient. Despite the great number of studies on this topic, a contextually relevant parameter that has received less attention is intensity recognition. In the present study, we investigated the potential advantage of coupling activity and intensity, namely, Activity-Intensity, in accelerometer data to improve the description of daily activities of individuals. We further tested two alternatives for supervised classification. In the first alternative, the activity and intensity are inferred together by applying a single classifier algorithm. In the other alternative, the activity and intensity are classified separately. In both cases, the algorithms used for classification are k-Nearest Neighbors (KNN), Support Vector Machine (SVM), and Random Forest (RF). The results showed the viability of the classification with good accuracy for Activity-Intensity recognition. The best approach was KNN implemented in the single classifier alternative, which resulted in 79% of accuracy. Using two classifiers, the result was 97% accuracy for activity recognition (Random Forest), and 80% for intensity recognition (KNN), which resulted in 78% for activity-intensity coupled. These findings have potential applications to improve the contextualized evaluation of movement by health professionals in the form of a decision system with expert rules.

Interactions between emotion and action in the brain.

A growing literature supports the existence of interactions between emotion and action in the brain, and the central participation of the anterior midcingulate cortex (aMCC) in this regard. In the present functional magnetic resonance imaging study, we sought to investigate the role of self-relevance during such interactions by varying the context in which threating pictures were presented (with guns pointed towards or away from the observer). Participants performed a simple visual detection task following exposure to such stimuli. Except for voxelwise tests, we adopted a Bayesian analysis framework which evaluated evidence for the hypotheses of interest, given the data, in a continuous fashion. Behaviorally, our results demonstrated a valence by context interaction such that there was a tendency of speeding up responses to targets after viewing threat pictures directed towards the participant. In the brain, interaction patterns that paralleled those observed behaviorally were observed most notably in the middle temporal gyrus, supplementary motor area, precentral gyrus, and anterior insula. In these regions, activity was overall greater during threat conditions relative to neutral ones, and this effect was enhanced in the directed towards context. A valence by context interaction was observed in the aMCC too, where we also observed a correlation (across participants) of evoked responses and reaction time data. Taken together, our study revealed the context-sensitive engagement of motor-related areas during emotional perception, thus supporting the idea that emotion and action interact in important ways in the brain.

Exploring the effects of COVID-19-related traumatic events on the mental health of university students in Brazil: A cross-sectional investigation.

University students are vulnerable to mental health issues during their academic lives. During the COVID-19 pandemic, university students faced mental distress due to lockdowns and the transition to e-learning. However, it is not known whether these students were also affected specifically by COVID-19-related traumatic events. This study examined the impact of COVID-19-related traumatic events on 2277 university students from two federal institutions of higher education in Brazil. The university students completed an online questionnaire covering demographics, lifestyle habits, health characteristics, COVID-19-related traumatic events, and depression, anxiety, and stress symptoms. The results showed that an increased intensity of COVID-19-related traumatic events was positively associated with stress, anxiety, and depressive symptoms, and each specific type of event was associated with these symptoms. In addition, we found a negative association between these symptoms and male sex and age and a positive association with having or having had a history of cardiovascular, respiratory, neurological, or mental disorders or another disease diagnosed by a physician. In conclusion, this study emphasizes the heightened risk of mental health issues in university students in the face of COVID-19-related traumatic events. Women, young people and people who have or have had a history of disease were the most vulnerable to mental health issues during the COVID-19 pandemic.

Tonic immobility triggered by COVID-19-related trauma is associated with long-term PTSD symptoms.

During the COVID-19 pandemic healthcare workers were repeatedly exposed to traumatic experiences. Facing life-threatening events and repeated exposure to traumatic duty-related situations may cause posttraumatic stress disorder (PTSD). While tonic immobility has been considered a key vulnerability factor for PTSD, little is known about this relationship in the long term. In this study, we aimed to determine whether peritraumatic tonic immobility triggered by COVID-19-related trauma predicts PTSD symptom severity six to twelve months later. We conducted an online longitudinal survey using the PTSD Checklist for the DSM-5 (PCL-5) and the Tonic Immobility Scale to assess PTSD symptoms and the tonic immobility response, respectively. Multivariate regression models revealed a significant association between tonic immobility and PTSD symptoms. Each one-unit increase in the tonic immobility score was associated with a 1.5 % increase in the average PTSD symptom score six to twelve months after the traumatic event that triggered the tonic immobility. Furthermore, participants who showed significant or extreme levels of tonic immobility were 3.5 times or 7.3 times more likely to have a probable PTSD diagnosis, respectively. Hence, peritraumatic tonic immobility seems to have a lasting deleterious effect on mental health. Psychological treatment for health care professionals is urgent, and psychoeducation about the involuntary, biological nature of tonic immobility is essential to reduce suffering.

Emotionally subjective reactivity to cervical cytology pictures is modulated by expertise.

Our aims were to create a catalog of cytological pictures and to evaluate the valence (level of pleasantness/unpleasantness) and arousal (level of calm/excitement) of these pictures in individuals with different occupations. The sample consisted of medical and law college students and cytopathologists. Valence and arousal score for general pictures were not modulated by expertise in cytology. However, students judged the cytological pictures to be lower in valence and in arousal than the cytopathologists. The cytopathologists classified cytological pictures with lesions as lower in valence and higher in arousal than cytological pictures without lesions.

The different impacts of COVID-19 on the mental health of distinct health care worker categories.

The present study sought to explore the factors associated with the odds of having probable depression and posttraumatic stress disorder (PTSD) related to traumatic COVID-19 experiences and their impact on health care workers in distinct categories. In this cross-sectional study, 1843 health care workers (nurses, nurse technicians, physicians, physical therapists, and other healthcare workers) were recruited via convenience sampling. A survey was administered to obtain information regarding sociodemographic, occupational, and mental health status. Descriptive statistics and multivariable logistic regression were used for the analyses. Being a nurse technician was associated with an odds ratio of 1.76 for probable PTSD. No relation was observed between health care worker categories and the odds of probable depression. Additionally, being female and not receiving adequate PPE were related to greater odds of having probable PTSD and depression.

Stroop matching task: role of feature selection and temporal modulation.

We conducted an event-related potential (ERP) study to investigate the electrocortical dynamics of attentional feature-based processing in the Stroop matching task. Participants in the study (n = 37) compared the ink color of a colored word with the meaning of a color-word in white ink. The two task stimuli were presented simultaneously or with SOAs (Stimulus Onset Asynchrony) of 400 and 1,200 ms. The Stroop matching effect was maximal during SOA-0, was reduced at SOA-400, and was inverted at SOA-1200. We focused the ERP analysis on the N1 component. Paralleling the behavioral results, the N1 amplitude was greater for congruent stimuli than incongruent stimuli during SOA-0. This difference was attenuated at SOA-400, and at SOA-1200, an inverse pattern was observed. The results provide evidence that early selection processing participated in the Stroop matching task phenomenon and also suggest that the temporal modulation of early attention is a function of task characteristics such as SOA.

Association between distinct coping styles and heart rate variability changes to an acute psychosocial stress task.

Modern life comprises a myriad of stressful situations, ranging from life-threatening ones to others not so deadly, all of which activate a physiologic stress response. Engaging in healthy ways to cope can prevent us from wearing out our physiological systems. Heart rate variability (HRV) is often used as an index of emotion regulation response. Hence, our goal is to investigate whether the habitual use of coping strategies is related to a distinct pattern of HRV changes when the individual is exposed to a moderate psychosocial stressor. In this study, 60 female participants performed a psychosocial stress task-oral speech preparation-while ECG signals were collected during the whole experimental procedure. Heart rate (HR), HRV parameters (SDNN, RMSSD, LF, HF) and coping strategies (Brief COPE) were registered. Participants were divided into two groups (low and high groups) as a function of their scores on the maladaptive and adaptive coping strategies of the Brief COPE. As expected, the task alone induced increases in heart rate and reductions in HRV parameters. Additionally, the analyses revealed a different pattern of HRV (SDNN, RMSSD, LF and HF) changes in response to the stressor, with participants using less maladaptive strategies being able to maintain the HRV at baseline levels when confronting the stressor, while those using more maladaptive strategies reducing HRV during the task. These results show a different pattern of HRV changes as a function of the coping style, suggesting a possible autonomic advantage, namely, the maintenance of HRV, in individuals who use maladaptive coping strategies less frequently.

Long-Term Influence of Incidental Emotions on the Emotional Judgment of Neutral Faces.

Background: Evidence indicates that the processing of facial stimuli may be influenced by incidental factors, and these influences are particularly powerful when facial expressions are ambiguous, such as neutral faces. However, limited research investigated whether emotional contextual information presented in a preceding and unrelated experiment could be pervasively carried over to another experiment to modulate neutral face processing. Objective: The present study aims to investigate whether an emotional text presented in a first experiment could generate negative emotion toward neutral faces in a second experiment unrelated to the previous experiment. Methods: Ninety-nine students (all women) were randomly assigned to read and evaluate a negative text (negative context) or a neutral text (neutral text) in the first experiment. In the subsequent second experiment, the participants performed the following two tasks: (1) an attentional task in which neutral faces were presented as distractors and (2) a task involving the emotional judgment of neutral faces. Results: The results show that compared to the neutral context, in the negative context, the participants rated more faces as negative. No significant result was found in the attentional task. Conclusion: Our study demonstrates that incidental emotional information available in a previous experiment can increase participants' propensity to interpret neutral faces as more negative when emotional information is directly evaluated. Therefore, the present study adds important evidence to the literature suggesting that our behavior and actions are modulated by previous information in an incidental or low perceived way similar to what occurs in everyday life, thereby modulating our judgments and emotions.

Vulnerability and Protective Factors for PTSD and Depression Symptoms Among Healthcare Workers During COVID-19: A Machine Learning Approach.

Background: Healthcare workers are at high risk for developing mental health problems during the COVID-19 pandemic. There is an urgent need to identify vulnerability and protective factors related to the severity of psychiatric symptoms among healthcare workers to implement targeted prevention and intervention programs to reduce the mental health burden worldwide during COVID-19. Objective: The present study aimed to apply a machine learning approach to predict depression and PTSD symptoms based on psychometric questions that assessed: (1) the level of stress due to being isolated from one's family; (2) professional recognition before and during the pandemic; and (3) altruistic acceptance of risk during the COVID-19 pandemic among healthcare workers. Methods: A total of 437 healthcare workers who experienced some level of isolation at the time of the pandemic participated in the study. Data were collected using a web survey conducted between June 12, 2020, and September 19, 2020. We trained two regression models to predict PTSD and depression symptoms. Pattern regression analyses consisted of a linear epsilon-insensitive support vector machine (ε-SVM). Predicted and actual clinical scores were compared using Pearson's correlation coefficient (r), the coefficient of determination (r2), and the normalized mean squared error (NMSE) to evaluate the model performance. A permutation test was applied to estimate significance levels. Results: Results were significant using two different cross-validation strategies to significantly decode both PTSD and depression symptoms. For all of the models, the stress due to social isolation and professional recognition were the variables with the greatest contributions to the predictive function. Interestingly, professional recognition had a negative predictive value, indicating an inverse relationship with PTSD and depression symptoms. Conclusions: Our findings emphasize the protective role of professional recognition and the vulnerability role of the level of stress due to social isolation in the severity of posttraumatic stress and depression symptoms. The insights gleaned from the current study will advance efforts in terms of intervention programs and public health messaging.

Tonic Immobility is Associated with PTSD Symptoms in Traumatized Adolescents.

PURPOSE: Growing evidence suggests that peritraumatic tonic immobility, an involuntary defensive response that involves extreme physical immobility and the perceived inability to escape, is a significant predictor of post-traumatic stress disorder (PTSD) symptomatology. However, this issue has not been specifically addressed in adolescents. Here, we investigated whether tonic immobility response experienced during the worst childhood or adolescent trauma is associated with PTSD symptom severity in a non-clinical student sample. METHODS: The sample was composed of students in 9th grade who were attending public and private schools. Symptoms of post-traumatic stress and tonic immobility were assessed using questionnaires. We performed bivariate and multivariate negative binomial regressions to examine whether tonic immobility was associated with PTSD symptomatology after controlling for confounders (peritraumatic dissociation, peritraumatic panic reactions, gender, age and time since trauma). RESULTS: We found an association between tonic immobility and PTSD symptom severity, even after controlling for confounders. Therefore, tonic immobility is associated with PTSD symptoms in trauma-exposed adolescents. CONCLUSION: These findings highlight tonic immobility as a possible risk factor that could be used to provide direction for more targeted trauma interventions for individuals, particularly those at risk for developing PTSD. Therefore, it contributes to preventing and reducing the psychiatric burden in adolescence and later in life.

Emotion affects action: Midcingulate cortex as a pivotal node of interaction between negative emotion and motor signals.

Affective pictures drive the activity of brain networks and impact behavior. We showed previously that viewing unpleasant pictures interfered in the performance of a basic nonemotional visual detection task. In the present study, we employed functional magnetic resonance imaging to test the hypothesis that behavioral interference may result from the interaction between negatively valenced and motor-related signals in the brain. As in our previous study (Pereira et al., 2006), participants performed a simple target detection task that followed the presentation of unpleasant or neutral pictures. Our results revealed that an unpleasant emotional context modulated evoked responses in several regions engaged by the simple target detection task. In particular, the midcingulate cortex was recruited when participants performed target detection trials during the unpleasant context, and signal responses in this region closely mirrored the pattern of behavioral interference (as revealed via reaction time). Our findings suggest that the midcingulate cortex may be an important site for the interaction between negatively valenced signals and motor signals in the brain and that it may be involved in the implementation of defensive responses, such as freezing.

Association between habitual use of coping strategies and posttraumatic stress symptoms in a non-clinical sample of college students: A Bayesian approach.

The present study investigated the influences of coping styles on posttraumatic stress symptoms (PTSS) among a sample of non-clinical college students who were exposed to traumatic events. Ninety-nine college students participated in the study. However, the sample used in the analyses consisted of only 37 participants who fulfilled the DSM-IV criterion A for Posttraumatic Stress Disorder (PTSD) diagnosis. The PTSD Checklist-Civilian Version (PCL-C) and the Brief COPE were used to assess the participants' PTSS and habitual use of coping strategies, respectively. Bayesian and frequentist correlations showed that emotion-focused coping style was negatively associated with PTSS, while dysfunctional coping style was positively related to PTSS. In the subsequent linear regression on both statistical framework, dysfunctional coping was the only consistent variable predicting more PTSD symptoms. The findings presented here show that lower use of adaptive coping (emotion-focused) and higher use of dysfunctional coping styles on a daily basis are associated to PTSS severity in a non-clinical sample of college students. According to the Bayesian approach, which permits more generalization of data, dysfunctional coping style is determinant to higher levels of PTSS. These findings add new data to the body of research that highlight the critical role of distinct coping strategies in the severity of PTSS.

Inhibitory mechanisms involved in Stroop-matching and stop-signal tasks and the role of impulsivity.

Stroop-like and stop-signal tasks are commonly used to evaluate "inhibition", a multifaceted concept fundamental to better understanding of executive functions. Both tasks demand inhibitory processes for their execution; the first requires inhibition of an irrelevant attribute, while the second involves the inhibition of a prepotent motor response. Impulsivity and decision-making represent two other factors that could be associated to executive control and to inhibitory dyscontrol. In this study we developed a behavioral protocol combining the Stroop-matching (a variation of the classic Stroop task) and the stop-signal tasks to investigate possible interactions between the inhibitory mechanisms involved in both tasks. Moreover, we searched for associations between behavioral performance of healthy participants, and self-reported impulsivity and decision-making processes assessed by the BIS-11 scale and IGT, respectively. Our results showed that the primary-task reaction time in the Stroop-matching task influenced the ability to inhibit motor responses in the stop-signal task. Moreover, impulsiveness scores (but not decision-making) were associated to behavioral performance. Importantly, motor and attentional impulsiveness correlated differently to performance depending on the existence of stop-signal trials in the task. Our protocol revealed promising findings concerning the interaction between different inhibitory processes and their association with impulsivity levels.

Bonding Pictures: Affective Ratings Are Specifically Associated to Loneliness But Not to Empathy.

Responding to pro-social cues plays an important adaptive role in humans. Our aims were (i) to create a catalog of bonding and matched-control pictures to compare the emotional reports of valence and arousal with the International Affective Picture System (IAPS) pictures; (ii) to verify sex influence on the valence and arousal of bonding and matched-control pictures; (iii) to investigate if empathy and loneliness traits exert a specific influence on emotional reports for the bonding pictures. To provide a finer tool for social interaction studies, the present work defined two new sets of pictures consisting of "interacting dyads" (Bonding: N = 70) and matched controls "non-interacting dyads" (Controls: N = 70). The dyads could be either a child and an adult, or two children. Participants (N = 283, 182 women) were divided in 10 groups for the experimental sessions. The task was to rate the hedonic valence and emotional arousal of bonding and controls; and of pleasant, neutral, and unpleasant pictures from the IAPS. Effects of social-related traits, empathy and loneliness, on affective ratings were tested. Participants rated bonding pictures as more pleasant and arousing than control ones. Ratings did not differentiate bonding from IAPS pleasant pictures. Control pictures showed lower ratings than pleasant but higher ratings than neutral IAPS pictures. Women rated bonding and control pictures as more positive than men. There was no sex difference for arousal ratings. High empathic participants rated bonding and control pictures higher than low empathic participants. Also, they rated pleasant IAPS pictures more positive and arousing; and unpleasant pictures more negative and arousing than the less empathic ones. Loneliness trait, on the other hand, affected very specifically the ratings of bonding pictures; lonelier participants rated them less pleasant and less arousing than less lonely. Loneliness trait did not modulate ratings of other categories. In conclusion, high empathy seems related to emotional strength in general, while high loneliness seems to weaken the engagement in social interaction cues.

The Perception of Aversiveness of Surgical Procedure Pictures Is Modulated by Personal/Occupational Relevance.

It is well established that emotions are organized around two motivational systems: the defensive and the appetitive. Individual differences are relevant factors in emotional reactions, making them more flexible and less stereotyped. There is evidence that health professionals have lower emotional reactivity when viewing scenes of situations involving pain. The objective of this study was to investigate whether the rating of pictures of surgical procedure depends on their personal/occupational relevance. Fifty-two female Nursing (health discipline) and forty-eight Social Work (social science discipline) students participated in the experiment, which consisted of the presentation of 105 images of different categories (e.g., neutral, food), including 25 images of surgical procedure. Volunteers judged each picture according to its valence (pleasantness) and arousal using the Self-Assessment Manikin scale (dimensional approach). Additionally, the participants chose the word that best described what they felt while viewing each image (discrete emotion perspective). The average valence score for surgical procedure pictures for the Nursing group (M = 4.57; SD = 1.02) was higher than the score for the Social Work group (M = 3.31; SD = 1.05), indicating that Nursing students classified those images as less unpleasant than the Social Work students did. Additionally, the majority of Nursing students (65.4%) chose "neutral" as the word that best described what they felt while viewing the pictures. In the Social Work group, disgust (54.2%) was the emotion that was most frequently chosen. The evaluation of emotional stimuli differed according to the groups' personal/occupational relevance: Nursing students judged pictures of surgical procedure as less unpleasant than the Social Work students did, possibly reflecting an emotional regulation skill or some type of habituation that is critically relevant to their future professional work.

Amygdala responses to unpleasant pictures are influenced by task demands and positive affect trait.

The role of attention in emotional processing is still the subject of debate. Recent studies have found that high positive affect in approach motivation narrows attention. Furthermore, the positive affect trait has been suggested as an important component for determining human variability in threat reactivity. We employed functional magnetic resonance imaging to investigate whether different states of attention control would modulate amygdala responses to highly unpleasant pictures relative to neutral and whether this modulation would be influenced by the positive affect trait. Participants (n = 22, 12 male) were scanned while viewing neutral (people) or unpleasant pictures (mutilated bodies) flanked by two peripheral bars. They were instructed to (a) judge the picture content as unpleasant or neutral or (b) to judge the difference in orientation between the bars in an easy condition (0 or 90(∘) orientation difference) or (c) in a hard condition (0 or 6(∘) orientation difference). Whole brain analysis revealed a task main effect of brain areas related to the experimental manipulation of attentional control, including the amygdala, dorsolateral prefrontal cortex, and posterior parietal cortex. Region of interest analysis showed an inverse correlation (r = -0.51, p < 0.01) between left amygdala activation and positive affect level when participants viewed unpleasant stimuli and judged bar orientation in the easy condition. This result suggests that subjects with high positive affect exhibit lower amygdala reactivity to distracting unpleasant pictures. In conclusion, the current study suggests that positive affect modulates attention effect on unpleasant pictures, therefore attenuating emotional responses.

Exposure to trauma-relevant pictures is associated with tachycardia in victims who had experienced an intense peritraumatic defensive response: the tonic immobility.

Tonic immobility is an involuntary, last-ditch defensive reaction characterized by physical inactivity in a context of inescapable threat that has been described in many species, including humans. The occurrence of this defensive response is a predictor of the severity of psychiatric disorders and may be considered as an index of an intense reaction to a traumatic event. Here, we investigated whether the retrospective reports of peritraumatic tonic immobility reaction in participants exposed to a traumatic event would modify their cardiac responses to pictures related to their trauma. Using a questionnaire of life-threating events, we selected students who experienced violent crime as their most intense trauma and students who had never experienced a violent crime trauma, but experienced other traumatic events. All participants completed a questionnaire that estimated the intensity of tonic immobility during their most intense trauma. Electrocardiographic recordings were collected during exposure to pictures. Participants viewed emotional pictures (human attack with guns) and neutral pictures. These emotional stimuli were selected to be trauma-relevant to the violent crime group and non trauma-relevant to the no violent crime trauma group. Violent crime group showed a positive correlation between heart rate changes after viewing trauma-related pictures and tonic immobility scores. We observed that low tonic immobility scores were associated with bradycardia and high scores with tachycardia in response to trauma-relevant pictures. For the no violent crime group, no significant correlation was detected. These results suggest that the relevance of the stimuli and the magnitude of the defensive response during a previous trauma event were important factors triggering more intense defensive responses.

Emotion and attention interaction: a trade-off between stimuli relevance, motivation and individual differences.

Mounting evidence suggests that the neural processing of emotional stimuli is prioritized. However, whether the processing of emotional stimuli is dependent on attention remains debatable. Several studies have investigated this issue by testing the capacity of emotional distracters to divert processing resources from an attentional main task. The attentional load theory postulates that the perceptual load of the main task determines the selective processing of the distracter. Although we agree with this theory, we also suggest that other factors could be important in determining the association between the load of the main task and distracter processing, namely, (1) the relevance of the to-be ignored stimuli and (2) the engagement in the main task due to motivation. We postulate that these factors function as opposite forces to influence distracter processing. In addition, we propose that this trade-off is modulated by individual differences. In summary, we suggest that the relationship between emotion and attention is flexible rather than rigid and depends on several factors. Considering this perspective may help us to understand the divergence in the results described by several studies in this field.