Impaired emotional contagion following severe traumatic brain injury

Empathy deficits are widely-documented in individuals after severe traumatic brain injury (TBI). This study examined the relationship between empathy deficits and psychophysiological responsivity in adults with TBI to determine if impaired responsivity is ameliorated through repeated emotional stimulus presentations. Nineteen TBI participants (13 males; 41 years) and 25 control participants (14 males; 31 years) viewed five repetitions of six 2-min film clip segments containing pleasant, unpleasant, and neutral content. Facial muscle responses (zygomaticus and corrugator), tonic heart rate (HR) and skin conductance level (SCL) were recorded. Mean responses for each viewing period were compared to a pre-experiment 2-min resting baseline period. Self-reported emotional empathy was also assessed. TBI participants demonstrated identical EMG response patterns to controls, i.e. an initial large facial response to both pleasant and unpleasant films, followed by habituation over repetitions for pleasant films, and sustained response to unpleasant films. Additionally, an increase in both arousal and HR deceleration to stimulus repetitions was found, which was larger for TBI participants. Compared to controls, TBI participants self-reported lower emotional empathy, and had lower resting arousal, and these measures were positively correlated. Results are consistent with TBI producing impairments in emotional empathy and responsivity. While some normalisation of physiological arousal appeared with repeated stimulus presentations, this came at the cost of greater attentional effort.     

Autonomic and neural correlates of dysregulated arousal in severe traumatic brain injury

Severe traumatic brain injury (TBI) in adults is associated with abnormalities in arousal and emotional responsivity, which are observed physiologically, behaviourally and via self-report measures. While an accurate measure of physiological arousal is debated, ,  and  have consistently shown an inverse relationship between skin conductance level (SCL), and mean alpha power (alpha) during an eyes-closed resting condition (EC), accompanied by an increase in SCL and corresponding decrease in alpha during eyes-open (EO). Thus, alpha may provide a novel index of autonomic arousal. This study aimed to elucidate the neural and autonomic correlates of arousal disturbances in TBI.     

The influence of attention and arousal on emotion perception in adults with severe traumatic brain injury

Many people with traumatic brain injury (TBI) have poor emotion recognition, with negative emotions more frequently impaired. They can also display abnormal affective responses to emotionally charged material, however, the mechanisms underpinning such deficits are unclear. This study examined whether affective responsivity can be improved by focusing attention and whether responsivity is associated with perception accuracy. Eighteen adults with moderate-to-severe TBI and 18 control participants viewed facial expressions while skin conductance (SCR) and evoked cardiac deceleration (ECD) (used as indices of orientation) and skin conductance levels (SCL) (used as an index of phasic arousal) were monitored. They viewed two blocks of faces (8 angry and 8 happy per block), passively in the first block and with the instruction to identify the emotional expression in the second. No differences between conditions, emotions or groups were found using SCR. Both groups demonstrated increasing ECD for the attend condition relative to the passive condition. For the passive task the control group showed increasing SCL (sensitisation) over trials when viewing angry faces and decreasing SCL (habituation) to happy faces. No differences between emotions were shown for the TBI group who rapidly habituated to both expressions. For the attend task, there was no evidence of habituation for either expression for either the control or TBI participants. Physiological measures did not correlate to accuracy in recognising emotions. The results suggest that increasing attentional demands improves orientation and emotional engagement (arousal) to emotional faces following TBI. However, the relationship to this and emotion perception accuracy remains unclear.     

Psychophysiological investigations in depersonalization disorder and effects of electrodermal biofeedback

Previous studies investigating depersonalization disorder (DPD) report a lower baseline skin conductance level (SCL) and attenuated skin conductance response (SCR) to emotive stimuli. We hypothesized that increasing physiological arousal levels via electrodermal biofeedback may ameliorate disembodiment and emotional numbing symptomatology. Real-time versus sham biofeedback yielded a significant SCL increase after just 3 real-time biofeedback sessions in healthy volunteers. Subsequently, a randomized controlled biofeedback trial was administered with DPD patients. Findings were not replicated as SCL tended to fall, curiously more substantially in the real-time condition, concomitant with increased low- and high-frequency heart rate variability. To further investigate abnormal autonomic regulation in DPD, we compared basal autonomic activity between patients and healthy volunteers and found the former to be significantly more labile, indexed by greater nonspecific SCRs and higher resting SCLs. Rather than low sympathetic arousal, DPD might be better characterized by abnormal autonomic regulation affecting emotional and physiological responsivity.     

Psychophysiological Responses to Emotional Stimuli in Children and Adolescents with Autism and Fragile X Syndrome

Individuals with autism demonstrate atypical and variable responses to social and emotional stimuli, perhaps reflecting heterogeneity of the disorder. The goal of this study was to determine whether unique profiles of psychophysiological responses to such stimuli could be identified in individuals diagnosed with autism spectrum disorder (ASD), with fragile X syndrome (FXS), and with comorbid autism and fragile X syndrome (ASD + FXS), and in typically developing (TYP) individuals. This study included 52 boys (ages 10–17): idiopathic ASD (n = 12), FXS (n = 12), comorbid ASD + FXS (n = 17), and TYP (n = 11). Physiological responses, including potentiated startle, electrodermal response, heart rate variability, and vagal tone, were collected concurrently while participants viewed emotionally evocative pictures of human faces or nonsocial images. Although some of these measures have been utilized separately for investigations on these diagnostic groups, they have not been considered together. Results using Kruskal-Wallis one-way analysis of variance by ranks indicate statistically significant differences in distributions of autonomic regulation responses between groups. The most notable differences were between the ASD group and both the FXS groups on measures of sympathetic activity, with FXS groups evincing increased activity. Also, both the ASD and ASD + FXS groups showed significantly decreased parasympathetic activity compared with FXS and TYP groups. In addition, the ASD + FXS group demonstrated a unique distribution of startle potentiation and arousal modulation. This study provides evidence that autonomic arousal and regulation profiles could be useful for distinguishing subgroups of autism and shed light on the variability underlying emotional responsivity.     

Automatic facial responses to briefly presented emotional stimuli in autism spectrum disorder

Emotion processing, including automatic facial mimicry, plays an important role in social reciprocity. Disruptions in these processes have implications for individuals with impaired social functioning, such as autism spectrum disorders (ASDs). Past research has demonstrated that ASDs are impaired in the recognition of briefly presented emotions and display atypical mimicry of emotions presented for protracted duration. Mimicry (electromyography; EMG) of briefly presented emotions was investigated in adults with ASDs. Concurrent measures of skin conductance and cardiac responses were used as markers of orientation and stimulus detection, respectively. A backward masking task was employed whereby the emotional face (happy, angry) was presented for 30 ms followed by a neutral face “mask”. An implicit comparison task required rapid gender identification. The ASD group failed to differentiate by valence in their EMG (zygomaticus, corrugator) and demonstrated atypical pre- and post-stimulus arousal. These findings may provide a potential mechanism for marked deficits in social reciprocity.     

Physiological blunting during pregnancy extends to induced relaxation

There is accumulating evidence that pregnancy is accompanied by hyporesponsivity to physical, cognitive, and psychological challenges. This study evaluates whether observed autonomic blunting extends to conditions designed to decrease arousal. Physiological and psychological responsivity to an 18-min guided imagery relaxation protocol in healthy pregnant women during the 32nd week of gestation (n = 54) and non-pregnant women (n = 28) was measured. Data collection included heart period (HP), respiratory sinus arrhythmia (RSA), tonic and phasic measures of skin conductance (SCL and NS-SCR), respiratory period (RP), and self-reported psychological relaxation. As expected, responses to the manipulation included increased HP, RSA, and RP and decreased SCL and NS-SCR, followed by post-manipulation recovery. However, responsivity was attenuated for all physiological measures except RP in pregnant women, despite no difference in self-reported psychological relaxation. Findings support non-specific blunting of physiological responsivity during pregnancy.     

Sex differences in empathy for pain: What is the role of autonomic regulation?

Empathy involves both affective and cognitive components whereby we understand, and express concerns for, the experiences of others. Women typically have superior trait empathy compared with men, which seems to have a neurological basis with sex differences in the structure and function of neural networks involved in empathy. This study investigated sex differences in empathy for pain using the Empathy for Pain Scale, and examined whether these trait differences were associated with disruptions in autonomic regulation, specifically via the parasympathetic nervous system (measured through the square root of the mean squared differences of successive R‐R intervals; RMSSD) both at rest and during a socioevaluative stress task (i.e., the serial sevens task). Compared with men, women reported higher empathic concern (Cohen's r = .25) and affective distress (Cohen's d = 0.65) toward another in pain. In both men and women, there was a decrease in lnRMSSD in the stress task compared to rest. Sex moderated the relationship between resting lnRMSSD and self‐reported empathic concern. Specifically, there was no clear association between empathic concern and lnRMSSD in men whereas in women there was a negative relationship, with lower resting lnRMSSD associated with higher empathic concern, and higher lnRMSSD associated with lower levels of empathic concern that were similar to men. These findings suggest that empathic feelings may result from poorer psychophysiological regulation, and concur with previous research displaying sex‐specific relationships between resting heart rate variability and emotion regulation abilities.     

Resting physiological arousal is associated with the experience of music-induced chills

In the study of emotion and autonomic nervous system functioning, resting physiological arousal is usually considered a negative characteristic. The present study examined the relationship between resting physiological arousal and positive emotional experience linked to psychophysiological arousal. We assessed resting physiological arousal using markers as high skin conductance level and low respiratory sinus arrhythmia, measured just before participants listened to their favorite music. Participants reported the sensation of chills (goose bumps, shivers) by pressing a mouse button while listening. The results indicated that individuals with resting physiological arousal frequently experience music-induced chills, which evoked unambiguous pleasurable feelings and an increase in skin conductance response. The current results, and the previously demonstrated relationship between resting physiological arousal and negative emotionality linked to psychophysiological arousal (e.g., anxiety, panic), suggest that resting physiological arousal may reflect sensitivity to psychophysiological arousal with both intense positive and negative emotions.     

Timing of caffeine's impact on autonomic and central nervous system measures: clarification of arousal effects

The timing of caffeine effects on arousal levels was examined. From previous work in our laboratory, an increase in skin conductance level (SCL) was used as the marker of arousal increase, and we sought to identify the timing of this and related effects following caffeine ingestion. A single oral dose of caffeine (250 mg) was used in a randomised double-blind placebo-controlled repeated-measures cross-over study. Eyes-closed resting electroencephalogram (EEG) and autonomic data (SCL, heart rate, respiration rate, and systolic and diastolic blood pressure) during 2 min epochs that commenced every 4 min after ingestion, were analysed. The SCL placebo data were used to identify potential arousal measures prior to examining caffeine effects. Caffeine was associated with increased SCL, increased respiratory rate and a global reduction in alpha power. There were no significant cardiovascular effects of caffeine-induced arousal. These caffeine results are consistent with our recent electrodermal and EEG studies of arousal, and confirm the potential use of caffeine as a simple means of experimentally modifying arousal levels without task-related confounds.     

Attenuation of positive and negative affect in men and women at increased risk for hypertension: A function of endogenous barostimulation?

We hypothesized that activation of endogenous baroreflexes would be associated with reduced responsivity to affective stimuli and that this effect would be enhanced in individuals at risk for hypertension. Images from the International Affective Picture System were presented during systolic and diastolic phases of the cardiac cycle. Affective responsivity was measured using electromyographic activity, skin conductance, and ratings of arousal and valence. Compared to offspring of normotensives, individuals with a parental history of hypertension showed reduced responsivity to both positive and negative affective stimuli; however, responsivity did not differ as a function of cardiac cycle phase. Although these findings do not support a barostimulation mechanism of affective dampening, it is premature to discount the baroreflex inhibition hypothesis given the limited affective reactions elicited by visual stimuli presented in the laboratory.     

High-functioning autism and schizophrenia: a comparison of an early and late onset neurodevelopmental disorder.

Autism and schizophrenia are separate neurodevelopmental disorders that share a number of interpersonal and cognitive deficits. The symptoms of autism first appear during early life while schizophrenic symptoms do not typically appear until adolescence at the earliest. Efforts have been made to characterize the pattern of cognitive function in both disorders, and certain resemblances have become apparent such as deficits in abstract reasoning and the more complex aspects of memory and language. The present study provided a comparison of cognitive function between the two disorders. The autistic sample consisted of well-diagnosed individuals with high-functioning autism (IQ> or =70). The schizophrenic sample was divided into four subgroups using Ward's method of cluster analysis. Participants received the Wechsler Adult Intelligence Scale-Revised (WAIS-R), the Halstead Category Test, the Trail Making test, and the Wisconsin Card Sorting test (WCST). The profile of the autism sample was compared with the four schizophrenia cluster profiles. The autism group resembled only one of the schizophrenia clusters, with both showing elevations on the WAIS-R Information and Block Design subtests and depressions on Comprehension and Digit Symbol. It was concluded that individuals with high-functioning autism have a cognitive profile that resembles that of an empirically derived subgroup of schizophrenia patients but that does not resemble profiles found in other schizophrenia subgroups. The pattern itself, marked by a relatively depressed score on the Comprehension subtest among the Verbal subtests and a relatively elevated score on Block Design among the Performance subtests, has been characterized in the past as a prototypic profile for high-functioning autism.     

Resting sympathetic arousal moderates the association between parasympathetic reactivity and working memory performance in adults reporting high levels of life stress

The neurovisceral integration model stipulates that autonomic function plays a critical role in the regulation of higher‐order cognitive processes, yet most work to date has examined parasympathetic function in isolation from sympathetic function. Furthermore, the majority of work has been conducted on normative samples, which typically demonstrate parasympathetic withdrawal to increase arousal needed to complete cognitive tasks. Little is known about how autonomic regulation supports cognitive function in populations exposed to high levels of stress, which is critical given that chronic stress exposure alters autonomic function. To address this, we sought to characterize how parasympathetic (high‐frequency heart rate variability, HF‐HRV) and sympathetic (preejection period, PEP) measures of cardiac function contribute to individual differences in working memory (WM) capacity in a sample of high‐risk women. HF‐HRV and PEP were measured at rest and during a visual change detection measure of WM. Multilevel modeling was used to examine within‐person fluctuations in WM performance throughout the task concurrently with HF‐HRV and PEP, as well as between‐person differences as a function of resting HF‐HRV and PEP levels. Results indicate that resting PEP moderated the association between HF‐HRV reactivity and WM capacity. Increases in WM capacity across the task were associated with increases in parasympathetic activity, but only among individuals with longer resting PEP (lower sympathetic arousal). Follow‐up analyses showed that shorter resting PEP was associated with greater cumulative risk exposure. These results support the autonomic space framework, in that the relationship between behavior and parasympathetic function appears dependent on resting sympathetic activation.     

Emotional deficits in psychopathy and sexual sadism: implications for violent and sadistic behavior

While both psychopaths and sexual sadists engage in acts of predatory violence, little empirical work has examined the relationship between the two disorders. This paper outlines the constructs of psychopathy and sexual sadism and reviews the literature investigating the emotional lives of individuals with these disorders, paying particular attention to how emotional deficits might facilitate instrumental violence. Specifically, it is hypothesized that the emotion recognition and emotional experience deficits found among psychopaths, and perhaps present in sexual sadists, may lead to deficits in their ability to empathize with others, resulting in an increased likelihood for perpetrating instrumental violence. The relationship between empathy and aggression in psychopaths and sexual sadists is discussed, and distinctions are drawn between the two disorders with respect to their capacities to experience cognitive and affective empathy on a global level. Gaps in the literature are identified and additional areas of inquiry are suggested.     

Autonomic nervous system activity in emotion: A review

Autonomic nervous system (ANS) activity is viewed as a major component of the emotion response in many recent theories of emotion. Positions on the degree of specificity of ANS activation in emotion, however, greatly diverge, ranging from undifferentiated arousal, over acknowledgment of strong response idiosyncrasies, to highly specific predictions of autonomic response patterns for certain emotions. A review of 134 publications that report experimental investigations of emotional effects on peripheral physiological responding in healthy individuals suggests considerable ANS response specificity in emotion when considering subtypes of distinct emotions. The importance of sound terminology of investigated affective states as well as of choice of physiological measures in assessing ANS reactivity is discussed.     

Early glycinergic axon contact with the Mauthner neuron during zebrafish development

One important aspect of empathy is a “resonance mechanism”, which includes emotional cue detection, facial mimicry (measured by electromyography, EMG) and a specific cortical response. This study explored the convergence of these three measures of affective empathy. The twenty students who took part in the study were required to empathise with the situation by entering into the other person's situation. The four emotions portrayed were anger, fear, happiness, and neutral, and the subjects were instructed to make a two-alternative response (emotion or no emotion) to each emotion. A repeated transcranial magnetic stimulation was used to produce a temporary inhibition of the medial prefrontal cortex (MPFC). The results support the hypothesis that there is a direct relationship between emotional cue recognition, EMG-measured facial response and prefrontal activity. First, both facial expression detection and autonomic mimicry in reaction to emotional faces were systematically modulated in response to inhibition of the MPFC. Second, the MPFC was implicated in facial cue detection and the subsequent autonomic response because an impaired performance on both measures was observed when this brain area was inhibited. Third, this effect increased when negative-valenced stimuli (angry and fearful faces) were presented to the subjects. These results revealed a significant effect of the MPFC on both cue detection and facial mimicry that was distinctly related to different types of emotions.     

Autism spectrum disorder and psychopathy: shared cognitive underpinnings or double hit?

BACKGROUND: We measured psychopathic traits in boys with autism spectrum disorder (ASD) selected for difficult and aggressive behaviour. We asked (i) whether psychopathic tendencies can be measured in ASD independent of the severity of autistic behaviour; (ii) whether individuals with ASD with callous-unemotional (CU) traits differ in their cognitive profile from those without such traits; and (iii) how the cognitive data from this study compare with previous data of youngsters with psychopathic tendencies. METHOD: Twenty-eight ASD boys were rated on psychopathic tendencies, autistic traits and a range of cognitive measures assessing mentalizing ability, executive functions, emotion recognition and ability to make moral-conventional distinction. RESULTS: Our results indicate that psychopathic tendencies are not related to severity of ASD. In addition, such tendencies do not seem to be related to core autistic cognitive deficits, specifically in 'mind-reading' or executive function. Boys with co-occurring ASD and CU tendencies share some behaviours and aspects of cognitive profile with boys who have psychopathic tendencies alone. CONCLUSIONS: Callous/psychopathic acts in a small number of individuals with ASD probably reflect a 'double hit' involving an additional impairment of empathic response to distress cues, which is not part and parcel of ASD itself.     

Regional brain activation as a biological marker of affective responsivity to acute exercise: influence of fitness

Previous research has shown that regional brain activation, assessed via frontal electroencephalographic (EEG) asymmetry, predicts affective responsivity to aerobic exercise. To replicate and extend this work, in the present study we examined whether resting brain activation was associated with affective responses to an acute bout of aerobic exercise and the extent to which aerobic fitness mediated this relationship. Participants (high-fit, n = 22; low/moderate-fit, n = 45) ran on a treadmill for 30 min at 75% VO2max. EEG and affect were assessed pre- and 0-, 10-, 20-, and 30-min postexercise. Resting EEG asymmetry predicted positive affect (as measured by the energetic arousal subscale of the Activation Deactivation Adjective Check List) postexercise. Furthermore, resting frontal EEG asymmetry predicted affect only in the high-fit group, suggesting the effect might be mediated by some factor related to fitness. It was also shown that subjects with relatively greater left frontal activation had significantly more energy (i.e., activated pleasant affect) following exercise than subjects with relatively greater right frontal activation. In conclusion, aerobic fitness influenced the relationship between resting frontal asymmetry and exercise-related affective responsivity.     

Autonomie responsivity following closed head injury.

It has recently been suggested that certain posttraumatic head injury patients exhibit impaired central nervous system arousal mechanisms, which may underlie or contribute to subsequent behavioral and cognitive disturbance. The present study examined skin conductance levels and responsivity in a group of 15 patients recovering from closed head injuries (CHIs) with 15 matched controls. Measurements were taken during rest periods and two activation periods. Activation periods consisted of 1) a series of 80 dB tones; and 2) a cognitive task (Symbol Digit Modalities Test). Patients exhibited significantly lower levels of skin conductance and significantly fewer responses than the control group. Group by task interactions were also significant, indicating that the control group was much more responsive during both activation periods. Skin conductance responsivity in the patient group was not found to be associated with duration of posttraumatic amnesia, behavioral disturbance, or attentional functioning, suggesting that the relationship between decreased autonomic arousal and cognitive or behavioral disturbance following CHI may be coincidental.     

Autonomic and electrophysiological correlates of emotional intensity in older and younger adults

Anterior cingulate cortex (ACC) is involved in the modulation of autonomic activity, emotional responsivity, and the monitoring of goal-directed behavior. However, these functions are rarely studied together to determine how they relate or whether their pattern of relation changes with age. We recorded respiratory sinus arrhythmia (RSA), an index of autonomic activity, error-related event related potentials (ERN/Pe), generated in ACC, and the self-reported intensity of 5 basic emotions in older and younger adults. Emotional intensity did not differ with age. The ERN/Pe and RSA were reduced with age and related specifically to sadness intensity for both groups. When examined together, RSA accounted for the relation between ERN/Pe and sadness. This is consistent with a model of medial prefrontal function in which autonomic processes mediate the relation between cognitive control and affective regulation, a pattern that also did not differ with age.