Manipulation of heart rate variability can modify response to anger-inducing stimuli

Research suggests that heart rate variability (HRV) is a physiological indicator of the flexibility of the autonomic nervous system and can provide an objective measure of an individual’s ability to appropriately match emotional responses to environmental demands. The present study investigated whether angry response to emotional stimuli was related to HRV, and whether manipulation of HRV using biofeedback could change the anger response in a healthy adult population. Fifty-eight participants received HRV biofeedback (n = 29) or an active control condition (n = 29). HRV measures included standard deviation of normal-to-normal intervals (SDNN), low-frequency (LF) and high-frequency (HF) power, and was recorded across three sessions: baseline, training, and anger induction. The anger induction procedure resulted in increased subjective experience of anger, as well as physiological changes. The biofeedback group had higher HRV than active controls both during the training session (SDNN and LF HRV) and during anger induction (LF HRV). HRV during anger induction was significantly associated with self-reported emotional response for participants receiving biofeedback but not for active controls. Results provide support for HRV as an index of emotion regulation, specifically anger. Further research is needed to determine whether long-term HRV biofeedback can have a lasting effect on managing anger.     

Trait and state corticostriatal dysfunction in bipolar disorder during emotional face processing

Liu J, Blond BN, van Dyck LI, Spencer L, Wang F, Blumberg HP. Trait and state corticostriatal dysfunction in bipolar disorder during emotional face processing.
Bipolar Disord 2012: 14: 432–441. © 2012 The Authors. Journal compilation © 2012 John Wiley & Sons A/S. Objectives: Convergent evidence supports limbic, anterior paralimbic, and prefrontal cortex (PFC) abnormalities in emotional processing in bipolar disorder (BD) and suggests that some abnormalities are mood‐state dependent and others persist into euthymia. However, few studies have assessed elevated, depressed, and euthymic mood states while individuals processed emotional stimuli of varying valence to investigate trait‐ and state‐related neural system responses. Here, regional brain responses to positive, negative, and neutral emotional stimuli were assessed in individuals with BD during elevated, depressed, and euthymic mood states. Methods: One hundred and thirty‐four subjects participated in functional magnetic resonance imaging scanning while processing faces depicting happy, fearful, and neutral expressions: 76 with BD (18 in elevated mood states, 19 depressed, 39 euthymic) and 58 healthy comparison (HC) individuals. Analyses were performed for BD trait‐ and mood state‐related features. Results: Ventral anterior cingulate cortex (VACC), orbitofrontal cortex (OFC), and ventral striatum responses to happy and neutral faces were decreased in the BD group, compared to the HC group, and were not influenced by mood state. Elevated mood states were associated with decreased right rostral PFC activation to fearful and neutral faces, and depression was associated with increased left OFC activation to fearful faces. Conclusions: The findings suggest that abnormal VACC, OFC, and ventral striatum responses to happy and neutral stimuli are trait features of BD. Acute mood states may be associated with additional lateralized abnormalities of diminished right rostral PFC responses to fearful and neutral stimuli in elevated states and increased left OFC responses to fearful stimuli in depressed states.     

Linking Amygdala Persistence to Real-World Emotional Experience and Psychological Well-Being

Neural dynamics in response to affective stimuli are linked to momentary emotional experiences. The amygdala, in particular, is involved in subjective emotional experience and assigning value to neutral stimuli. Because amygdala activity persistence following aversive events varies across individuals, some may evaluate subsequent neutral stimuli more negatively than others. This may lead to more frequent and long-lasting momentary emotional experiences, which may also be linked to self-evaluative measures of psychological well-being (PWB). Despite extant links between daily affect and PWB, few studies have directly explored the links between amygdala persistence, daily affective experience, and PWB. To that end, we examined data from 52 human adults (67% female) in the Midlife in the United States study who completed measures of PWB, daily affect, and functional MRI (fMRI). During fMRI, participants viewed affective images followed by a neutral facial expression, permitting quantification of individual differences in the similarity of amygdala representations of affective stimuli and neutral facial expressions that follow. Using representational similarity analysis, neural persistence following aversive stimuli was operationalized as similarity between the amygdala activation patterns while encoding negative images and the neutral facial expressions shown afterward. Individuals demonstrating less persistent activation patterns in the left amygdala to aversive stimuli reported more positive and less negative affect in daily life. Further, daily positive affect served as an indirect link between left amygdala persistence and PWB. These results clarify important connections between individual differences in brain function, daily experiences of affect, and well-being.SIGNIFICANCE STATEMENT At the intersection of affective neuroscience and psychology, researchers have aimed to understand how individual differences in the neural processing of affective events map onto to real-world emotional experiences and evaluations of well-being. Using a longitudinal dataset from 52 adults in the Midlife in the United States (MIDUS) study, we provide an integrative model of affective functioning: less amygdala persistence following negative images predicts greater positive affect (PA) in daily life, which in turn predicts greater psychological well-being (PWB) seven years later. Thus, day-to-day experiences of PA comprise a promising intermediate step that links individual differences in neural dynamics to complex judgements of PWB.     

What aspects of emotional functioning are impaired in schizophrenia?

Disturbances in emotional functioning are a major cause of persistent functional disability in schizophrenia. However, it is not clear what specific aspects of emotional functioning are impaired. Some studies have indicated diminished experience of positive affect in individuals with schizophrenia, while others have not. The current study assessed emotional responses by 34 individuals with schizophrenia and 35 demographically matched healthy participants to 131 images sampling a wide range of emotional arousal and valence levels. Ratings of affective response elicited by individual images were highly correlated across the groups (r's>.90), indicating similar emotional experiences at the moment of stimulus exposure. However, the data did not indicate strong relationships between ratings of the emotional impact of the images and most measures of day-to-day emotional processing. These results demonstrate that individuals with schizophrenia report "normal" emotional responses to emotional stimuli, and thus suggests that deficits in emotional functioning associated with the disorder are likely to occur further downstream, and involve the effective integration of emotion and cognition for adaptive functioning in areas such as goal-setting, motivation, and memory.     

Naltrexone alters the processing of social and emotional stimuli in healthy adults

Endogenous opioids have complex social effects that may depend on specific receptor actions and vary depending on the “stage” of social behavior (e.g., seeking vs. responding to social stimuli). We tested the effects of a nonspecific opioid antagonist, naltrexone (NTX), on social processing in humans. NTX is used to treat alcohol and opiate dependence, and may affect both mu and kappa-opioid systems. We assessed attention (“seeking”), and subjective and psychophysiological responses (“responding”) to positive and negative social stimuli. Based on literature suggesting mu-opioid blockade impairs positive social responses, we hypothesized that NTX would decrease responses to positive social stimuli. We also tested responses to negative stimuli, which might be either increased by NTX’s mu-opioid effects or decreased by its kappa-opioid effects. Thirty-four healthy volunteers received placebo, 25 mg, or 50 mg NTX across three sessions under double-blind conditions. At each session, participants completed measures of attention, identification, and emotional responses for emotional faces and scenes. NTX increased attention to emotional expressions, slowed identification of sadness and fear, and decreased ratings of arousal for social and nonsocial emotional scenes. These findings are more consistent with anxiolytic kappa-antagonist than mu-blocking effects, suggesting effects on kappa receptors may contribute to the clinical effects of NTX.     

Insula–amygdala functional connectivity is correlated with habituation to repeated negative images

Behavioral habituation during repeated exposure to aversive stimuli is an adaptive process. However, the way in which changes in self-reported emotional experience are related to the neural mechanisms supporting habituation remains unclear. We probed these mechanisms by repeatedly presenting negative images to healthy adult participants and recording behavioral and neural responses using functional magnetic resonance imaging. We were particularly interested in investigating patterns of activity in insula, given its significant role in affective integration, and in amygdala, given its association with appraisal of aversive stimuli and its frequent coactivation with insula. We found significant habituation behaviorally along with decreases in amygdala, occipital cortex and ventral prefrontal cortex (PFC) activity with repeated presentation, whereas bilateral posterior insula, dorsolateral PFC and precuneus showed increased activation. Posterior insula activation during image presentation was correlated with greater negative affect ratings for novel presentations of negative images. Further, repeated negative image presentation was associated with increased functional connectivity between left posterior insula and amygdala, and increasing insula–amygdala functional connectivity was correlated with increasing behavioral habituation. These results suggest that habituation is subserved in part by insula–amygdala connectivity and involves a change in the activity of bottom-up affective networks.     

Ventromedial frontal lobe damage disrupts the accuracy, but not the speed, of value-based preference judgments

The ventromedial frontal lobe (VMF) plays a role in decision making, but its precise function remains unclear. Several lines of evidence suggest that VMF is involved in representing the economic value of options. A prior study from our lab has shown that patients with lesions to the VMF are less consistent than controls in making simple preference judgments between stimuli presented in pairs. Here, we followed up that observation in a larger sample, using more sensitive tasks, and examining the category-specificity of this effect. Patients with damage to VMF (N=15) were compared to patients with frontal damage sparing that region (N=8) and to demographically matched healthy control participants (N=23). Five separate preference tasks were administered, requiring subjects to indicate their preference for 12 stimuli presented two at a time, in all possible combinations. Categories included fruits, vegetables, colors, landscapes, and puppies. Choices were analyzed for internal consistency, and decision times were measured. Three control tasks with the same format, but requiring perceptual judgments, were also administered. VMF patients were significantly more erratic than both non-VMF and healthy control participants in their preference judgments across all stimulus categories. However, decision times, and the relationship between decision time and relative value, were similar to that seen in control participants. The groups did not differ in perceptual judgment performance. These findings add further weight to the claim that VMF plays a critical role in simple value-based decision-making under conditions of certainty. This region appears to be necessary for consistent choices across a variety of stimulus categories, supporting the view that human VMF represents the (relative) value of decision options rather generally. That such damage impairs decision 'accuracy' without affecting reaction time has implications for theories of the role of VMF in decision-making, arguing that this region may be critical for linking a particular value to a particular option.     

The transition from childhood to adolescence is marked by a general decrease in amygdala reactivity and an affect-specific ventral-to-dorsal shift in medial prefrontal recruitment

Understanding how and why affective responses change with age is central to characterizing typical and atypical emotional development. Prior work has emphasized the role of the amygdala and prefrontal cortex (PFC), which show age-related changes in function and connectivity. However, developmental neuroimaging research has only recently begun to unpack whether age effects in the amygdala and PFC are specific to affective stimuli or may be found for neutral stimuli as well, a possibility that would support a general, rather than affect-specific, account of amygdala-PFC development. To examine this, 112 individuals ranging from 6 to 23 years of age viewed aversive and neutral images while undergoing fMRI scanning. Across age, participants reported more negative affect and showed greater amygdala responses for aversive than neutral stimuli. However, children were generally more sensitive to both neutral and aversive stimuli, as indexed by affective reports and amygdala responses. At the same time, the transition from childhood to adolescence was marked by a ventral-to-dorsal shift in medial prefrontal responses to aversive, but not neutral, stimuli. Given the role that dmPFC plays in executive control and higher-level representations of emotion, these results suggest that adolescence is characterized by a shift towards representing emotional events in increasingly cognitive terms.     

‘Ecstasy’ as a social drug: MDMA preferentially affects responses to emotional stimuli with social content

3,4-Methylenedioxymethamphetamine (MDMA, ‘ecstasy’) is used recreationally to improve mood and sociability, and has generated clinical interest as a possible adjunct to psychotherapy. One way that MDMA may produce positive ‘prosocial’ effects is by changing responses to emotional stimuli, especially stimuli with social content. Here, we examined for the first time how MDMA affects subjective responses to positive, negative and neutral emotional pictures with and without social content. We hypothesized that MDMA would dose-dependently increase reactivity to positive emotional stimuli and dampen reactivity to negative stimuli, and that these effects would be most pronounced for pictures with people in them. The data were obtained from two studies using similar designs with healthy occasional MDMA users (total N = 101). During each session, participants received MDMA (0, 0.75 and 1.5 mg/kg oral), and then rated their positive and negative responses to standardized positive, negative and neutral pictures with and without social content. MDMA increased positive ratings of positive social pictures, but reduced positive ratings of non-social positive pictures. We speculate this ‘socially selective’ effect contributes to the prosocial effects of MDMA by increasing the comparative value of social contact and closeness with others. This effect may also contribute to its attractiveness to recreational users.     

Selective impairment of cognitive empathy for moral judgment in adults with high functioning autism

Faced with a moral dilemma, conflict arises between a cognitive controlled response aimed at maximizing welfare, i.e. the utilitarian judgment, and an emotional aversion to harm, i.e. the deontological judgment. In the present study, we investigated moral judgment in adult individuals with high functioning autism/Asperger syndrome (HFA/AS), a clinical population characterized by impairments in prosocial emotions and social cognition. In Experiment 1, we compared the response patterns of HFA/AS participants and neurotypical controls to moral dilemmas with low and high emotional saliency. We found that HFA/AS participants more frequently delivered the utilitarian judgment. Their perception of appropriateness of moral transgression was similar to that of controls, but HFA/AS participants reported decreased levels of emotional reaction to the dilemma. In Experiment 2, we explored the way in which demographic, clinical and social cognition variables including emotional and cognitive aspects of empathy and theory of mind influenced moral judgment. We found that utilitarian HFA/AS participants showed a decreased ability to infer other people’s thoughts and to understand their intentions, as measured both by performance on neuropsychological tests and through dispositional measures. We conclude that greater prevalence of utilitarianism in HFA/AS is associated with difficulties in specific aspects of social cognition.     

Different contributions of the human amygdala and ventromedial prefrontal cortex to decision-making.

The somatic marker hypothesis proposes that decision-making is a process that depends on emotion. Studies have shown that damage of the ventromedial prefrontal (VMF) cortex precludes the ability to use somatic (emotional) signals that are necessary for guiding decisions in the advantageous direction. However, given the role of the amygdala in emotional processing, we asked whether amygdala damage also would interfere with decision-making. Furthermore, we asked whether there might be a difference between the roles that the amygdala and VMF cortex play in decision-making. To address these two questions, we studied a group of patients with bilateral amygdala, but not VMF, damage and a group of patients with bilateral VMF, but not amygdala, damage. We used the "gambling task" to measure decision-making performance and electrodermal activity (skin conductance responses, SCR) as an index of somatic state activation. All patients, those with amygdala damage as well as those with VMF damage, were (1) impaired on the gambling task and (2) unable to develop anticipatory SCRs while they pondered risky choices. However, VMF patients were able to generate SCRs when they received a reward or a punishment (play money), whereas amygdala patients failed to do so. In a Pavlovian conditioning experiment the VMF patients acquired a conditioned SCR to visual stimuli paired with an aversive loud sound, whereas amygdala patients failed to do so. The results suggest that amygdala damage is associated with impairment in decision-making and that the roles played by the amygdala and VMF in decision-making are different.     

Emotional response deficits in schizophrenia: insights from affective science

Our understanding of the emotional features of schizophrenia has benefited greatly from the adoption of methods and theory from the field of affective science. This article covers basic concepts and methods from affective science on the psychological and neural mechanisms contributing to emotions and reviews the ways in which this research has advanced our understanding of emotional response deficits in schizophrenia. We review naturalistic studies and elicitation studies that evoke emotion responses among participants, including emotion expression, experience, and autonomic physiology. We also consider how these emotion response measures correspond to schizophrenia symptoms, and we focus particular attention on the issue of sex differences in emotional responding and how this may influence our understanding emotional functioning among individuals with schizophrenia.     

Neural correlates of effective and ineffective mood induction

Emotional reactivity and the ability to modulate an emotional state, which are important factors for psychological well-being, are often dysregulated in psychiatric disorders. Neural correlates of emotional states have mostly been studied at the group level, thereby neglecting individual differences in the intensity of emotional experience. This study investigates the relationship between brain activity and interindividual variation in subjective affect ratings. A standardized mood induction (MI) procedure, using positive facial expression and autobiographical memories, was applied to 54 healthy participants (28 female), who rated their subjective affective state before and after the MI. We performed a regression analysis with brain activation during MI and changes in subjective affect ratings. An increase in positive affective ratings correlated with activity in the amygdala, hippocampus and the fusiform gyrus (FFG), whereas reduced positive affect correlated with activity of the subgenual anterior cingulate cortex. Activations in the amygdala, hippocampus and FFG are possibly linked to strategies adopted by the participants to achieve mood changes. Subgenual cingulate cortex activation has been previously shown to relate to rumination. This finding is in line with previous observations of the subgenual cingulate’s role in emotion regulation and its clinical relevance to therapy and prognosis of mood disorders.     

An fMRI study of the interface between affective and cognitive neural circuitry in pediatric bipolar disorder

The pathophysiology of pediatric bipolar disorder (PBD) impacts both affective and cognitive brain systems. Understanding disturbances in the neural circuits subserving these abilities is critical for characterizing developmental aberrations associated with the disorder and developing improved treatments. Our objective is to use functional neuroimaging with pediatric bipolar disorder patients employing a task that probes the functional integrity of attentional control and affect processing. Ten euthymic unmedicated pediatric bipolar patients and healthy controls matched for age, sex, race, socioeconomic status, and IQ were scanned using functional magnetic resonance imaging. In a pediatric color word matching paradigm, subjects were asked to match the color of a word with one of two colored circles below. Words had a positive, negative or neutral emotional valence, and were presented in 30-s blocks. In the negative affect condition, relative to the neutral condition, patients with bipolar disorder demonstrated greater activation of bilateral pregenual anterior cingulate cortex and left amygdala, and less activation in right rostral ventrolateral prefrontal cortex (PFC) and dorsolateral PFC at the junction of the middle frontal and inferior frontal gyri. In the positive affect condition, there was no reduced activation of PFC or increased amygdala activation. The pattern of reduced activation of ventrolateral PFC and greater amygdala activation in bipolar children in response to negative stimuli suggests both disinhibition of emotional reactivity in the limbic system and reduced function in PFC systems that regulate those responses. Higher cortical cognitive areas such as the dorsolateral PFC may also be adversely affected by exaggerated emotional responsivity to negative emotions. This pattern of functional alteration in affective and cognitive circuitry may contribute to the reduced capacity for affect regulation and behavioral self-control in pediatric bipolar disorder.     

Role of the left amygdala and right orbital frontal cortex in emotional interference resolution facilitation in working memory

Previous research has shown that emotional information aids conflict resolution in working memory (Levens & Phelps, 2008). Using a Recency-probes working memory (WM) paradigm, Levens and Phelps found that positive and negative emotional stimuli reduced the amount of interference created when information that was once relevant conflicted with currently relevant information, suggesting that emotional information facilitates interference resolution in WM. To determine what regions of the prefrontal cortex (PFC) and temporal lobes are critical to the influence of emotional stimuli on interference resolution, we conducted a Recency-probes emotion paradigm with right and left unilateral frontal and temporal lobe lesion patients. The frontal lobe lesion patient group comprised individuals with unilateral ventral and dorsal PFC lesions. The temporal lobe lesion patient group comprised individuals with lesions of the amygdala and surrounding structures. Results indicate that when the left amygdala is damaged, emotional facilitation of interference resolution is absent (equal emotional and neutral interference levels), when the right orbital frontal cortex (OFC) is damaged, in contrast, emotional interference resolution is impaired (emotional interference levels are higher than neutral levels are). Based on these unique patterns we propose specific contributions for these regions in the emotional facilitation of interference resolution in WM.     

Functional differences among those high and low on a trait measure of psychopathy.

BACKGROUND: It has been established that individuals who score high on measures of psychopathy demonstrate difficulty when performing tasks requiring the interpretation of other's emotional states. The aim of this study was to elucidate the relation of emotion and cognition to individual differences on a standard psychopathy personality inventory (PPI) among a nonpsychiatric population. METHODS: Twenty participants completed the PPI. Following survey completion, a mean split of their scores on the emotional-interpersonal factor was performed, and participants were placed into a high or low group. Functional magnetic resonance imaging data were collected while participants performed a recognition task that required attention be given to either the affect or identity of target stimuli. RESULTS: No significant behavioral differences were found. In response to the affect recognition task, significant differences between high- and low-scoring subjects were observed in several subregions of the frontal cortex, as well as the amygdala. No significant differences were found between the groups in response to the identity recognition condition. CONCLUSIONS: Results indicate that participants scoring high on the PPI, although not behaviorally distinct, demonstrate a significantly different pattern of neural activity (as measured by blood oxygen level-dependent contrast)in response to tasks that require affective processing. The results suggest a unique neural signature associated with personality differences in a nonpsychiatric population.     

Affective resonance in response to others’ emotional faces varies with affective ratings and psychopathic traits in amygdala and anterior insula

Despite extensive research on the neural basis of empathic responses for pain and disgust, there is limited data about the brain regions that underpin affective response to other people’s emotional facial expressions. Here, we addressed this question using event-related functional magnetic resonance imaging to assess neural responses to emotional faces, combined with online ratings of subjective state. When instructed to rate their own affective response to others’ faces, participants recruited anterior insula, dorsal anterior cingulate, inferior frontal gyrus, and amygdala, regions consistently implicated in studies investigating empathy for disgust and pain, as well as emotional saliency. Importantly, responses in anterior insula and amygdala were modulated by trial-by-trial variations in subjective affective responses to the emotional facial stimuli. Furthermore, overall task-elicited activations in these regions were negatively associated with psychopathic personality traits, which are characterized by low affective empathy. Our findings suggest that anterior insula and amygdala play important roles in the generation of affective internal states in response to others’ emotional cues and that attenuated function in these regions may underlie reduced empathy in individuals with high levels of psychopathic traits.     

Emotionally anesthetized: media violence induces neural changes during emotional face processing

Media violence exposure causes increased aggression and decreased prosocial behavior, suggesting that media violence desensitizes people to the emotional experience of others. Alterations in emotional face processing following exposure to media violence may result in desensitization to others’ emotional states. This study used scalp electroencephalography methods to examine the link between exposure to violence and neural changes associated with emotional face processing. Twenty-five participants were shown a violent or nonviolent film clip and then completed a gender discrimination stop-signal task using emotional faces. Media violence did not affect the early visual P100 component; however, decreased amplitude was observed in the N170 and P200 event-related potentials following the violent film, indicating that exposure to film violence leads to suppression of holistic face processing and implicit emotional processing. Participants who had just seen a violent film showed increased frontal N200/P300 amplitude. These results suggest that media violence exposure may desensitize people to emotional stimuli and thereby require fewer cognitive resources to inhibit behavior.     

Glucose metabolic changes in the prefrontal cortex are associated with HPA axis response to a psychosocial stressor

The prefrontal cortex (PFC) has been well known for its role in higher order cognition, affect regulation and social reasoning. Although the precise underpinnings have not been sufficiently described, increasing evidence also supports a prefrontal involvement in the regulation of the hypothalamus-pituitary-adrenal (HPA) axis. Here we investigate the PFC's role in HPA axis regulation during a psychosocial stress exposure in 14 healthy humans. Regional brain metabolism was assessed using positron emission tomography (PET) and injection of fluoro-18-deoxyglucose (FDG). Depending on the exact location within the PFC, increased glucose metabolic rate was associated with lower or higher salivary cortisol concentration in response to a psychosocial stress condition. Metabolic glucose rate in the rostral medial PFC (mPFC) (Brodman area (BA) 9 and BA 10) was negatively associated with stress-induced salivary cortisol increases. Furthermore, metabolic glucose rate in these regions was inversely coupled with changes in glucose metabolic rate in other areas, known to be involved in HPA axis regulation such as the amygdala/hippocampal region. In contrast, metabolic glucose rate in areas more lateral to the mPFC was positively associated with saliva cortisol. Subjective ratings on task stressfulness, task controllability and self-reported dispositional mood states also showed positive and negative associations with the glucose metabolic rate in prefrontal regions. These findings suggest that in humans, the PFC is activated in response to psychosocial stress and distinct prefrontal metabolic glucose patterns are linked to endocrine stress measures as well as subjective ratings on task stressfulness, controllability as well as dispositional mood states.     

Facial expressions of emotion reveal neuroendocrine and cardiovascular stress responses.

BACKGROUND: The classic conception of stress involves undifferentiated negative affect and corresponding biological reactivity. The present study hypothesized a new conception, disaggregating stress into emotion-specific, contrasting patterns of biological response. Specifically, it hypothesized contrasting patterns for indignation (comprised of anger and disgust) versus fear. Moreover, it hypothesized that facial expressions of these emotions would signal corresponding biological stress responses. METHODS: Ninety-two adults engaged in annoyingly difficult stress-challenge tasks, during which cardiovascular responses, hypothalamic-pituitary-adrenocortical (HPA) axis responses (i.e., cortisol), emotional expressions (i.e., facial muscle movements), and subjective emotional experience were assessed. RESULTS: Pronounced individual differences emerged in specific emotional responses to the stressors. Analyses of facial expressions revealed that the more fear individuals displayed in response to the stressors, the higher their cardiovascular and cortisol responses to stress. By contrast, the more indignation individuals displayed in response to the same stressors the lower their cortisol levels and cardiovascular responses. CONCLUSIONS: Facial expressions of emotion signal biological responses to stress. Fear expressions signal elevated cortisol and cardiovascular reactivity; indignation signals attenuated cortisol and cardiovascular reactivity, patterns that implicate individual differences in stress appraisals. Rather than conceptualizing stress as generalized negative affect, studies can be informed by this emotion-specific approach to stress responses.