Relationships Between Behavioral Arousal and Some Components of Autonomic Arousal

The present experiment examined 11 male adolescents for relationships between the autonomic measures of heart rate (HR) and skin conductance (SC) and three rates of finger tapping, a) subject resting, b) DRL.5 sec, and c) FR5, as a measure of behavioral arousal. At each level of behavioral arousal, minimum, mean, and maximum HR were analyzed. Mean and maximum HR increased only at high arousal, while minimum HR increased with each increase in behavioral arousal. SC was higher during tapping than resting, but was uninfluenced by rate of tapping. The potential value of the maximum and minimum HR and SC measures as tools for inferring the role of parasympathetic versus sympathetic mechanisms in autonomic arousal was discussed. This paradigm provides a simple, nonaversive method for examining autonomic and behavioral arousal.     

Oxytocin response in a trust game and habituation of arousal

Oxytocin may be implicated in various sophisticated human processes, including attachment, trust, social perception, memory, and fear regulation. In this study, we explored the relationship between plasma oxytocin level measured after a task requiring intimate trust (secret sharing) and habituation of autonomic arousal (skin conductance response) in sixty healthy volunteers. Results revealed that oxytocin was elevated in the trust-related condition relative to a neutral baseline. In a cognitive stress condition (mental arithmetic task), there was no significant oxytocin elevation relative to the neutral condition. After controlling for age, gender, education, state anxiety and depression, we found a significant positive relationship between trust-related oxytocin level and habituation of autonomic arousal. This relationship was absent in the case of neutral (trust-unrelated) oxytocin level. These results suggest that the habituation of autonomic arousal is closely related to oxytocin released during trust-related social interactions.     

Effects of Brief Relaxation Training on Autonomic Response to Anxiety-Evoking Stimuli

Relaxation training procedures used in systematic desensitization are abbreviated forms of procedures developed by Jacobson to decrease muscle tension level and assumed by Gellhorn to affect autonomic balance. Autonomic response effects of relaxation training are sometimes considered secondary to either cognitive or autonomic level change. In the present experiment, specific instruction and training was provided in making relaxation responses to a cue stimulus which was used subsequently in two mild anxiety conditions. Brief relaxation training did not significantly affect either verbal report of anxiety or autonomic level following training, but did affect autonomic response in the anxiety conditions. The results suggest that autonomic response modification can be accomplished by instruction and relatively minimal training. Also, the results indicate that autonomic response effects need not be accompanied by either verbal report of greater relaxation or autonomic level modification. These results are difficult to account for by any theoretical model of desensitization which considers autonomic response change secondary to either cognitive or autonomic level change.     

The emotional consequences of social pragmatism: the psychophysiological correlates of self-monitoring

Self-monitoring refers to the extent to which people regulate their self-presentation by tailoring their behaviors to social situations. To examine the psychophysiological correlates of self-monitoring, we measured heart rate, skin conductance level, and EEG alpha of the frontal and parietal scalp regions during baseline and while anticipating an impromptu speech task. High self-monitors showed lower cortical activity in the frontal and parietal scalp regions than low self-monitors. Furthermore, self-monitoring scores were negatively correlated with skin conductance level when anticipating social threat. Social anxiety and depression did not account for these results. The findings suggest that high self-monitors show lower autonomic and cortical arousal than low self-monitors when anticipating social stress.     

Changes in Mood and Autonomic Functioning During the Menstrual Cycle

The autonomic nervous system activity and mood ratings of 12 women were studied 6 days a week for a complete menstrual cycle. The daily procedure consisted of a resting period, a series of 5 mild tones, time estimation (TE), and reaction time (RT) trials, and a final resting period. Significant increase in heart rate (HR), respiration rate, and body temperature, and a significant decrease in resting skin conductance (SC) were found during the luteal phase. During the ovulatory phase there were significant increases in autonomic responsivity, as shown by greater amplitude of SC response in the TE and RT situations as well as in faster SC drop-rate and greater HR variability. All of these autonomic variability measures coincided with a significant peak in feelings of elation and vigor. Significant age effects were that older women had higher basal body temperatures, less marked HR variability, and tended to have lower levels of SC, particularly in the luteal phase of the cycle. The results are discussed in terms of the psychophysiological effects of estrogen and progesterone.     

Autonomic Activity During Anticipation of An Aversive Tone in Noninstitutionalized Sociopaths

Fifteen noninstitutionalized, compulsive-gambler sociopaths and 15 controls were run in a modification of Hare's (1965b) gradient of fear paradigm. Both heart rate and bilateral skin conductance were averaged during 8 3-sec intervals prior to the presentation of a 95dB tone. The controls showed both earlier and larger electrodermal anticipation of the tone than the sociopaths. For both groups of subjects, electrodermal anticipation of the tone began sooner and was larger in amplitude in the right hand than in the left hand. There were no significant heart rate differences between the two groups of subjects.     

Autonomic arousal explains social cognitive abilities in high-functioning adults with autism spectrum disorder

Empirical research into behavioural profiles and autonomic responsivity in individuals with autism spectrum disorders (ASDs) is highly variable and inconsistent. Two preliminary studies of children with ASDs suggest that there may be subgroups of ASDs depending on their resting arousal levels, and that these subgroups show different profiles of autonomic responsivity. The aim of the present study was to determine whether (i) adults with high-functioning ASDs may be separated into subgroups according to variation in resting arousal; and (ii) these ASD arousal subgroups differ in their behavioural profiles for basic emotion recognition, judgements of trustworthiness, and cognitive and affective empathy. Thirty high-functioning adults with ASDs and 34 non-clinical controls participated. Resting arousal was determined as the average skin conductance (SCL) across a 2 min resting period. There was a subgroup of ASD adults with significantly lower resting SCL. These individuals demonstrated poorer emotion recognition, tended to judge faces more negatively, and had atypical relationships between SCL and affective empathy. In contrast, low cognitive empathy was a feature of all ASD adults. These findings have important implications for clinical interventions and future studies investigating autonomic functioning in ASDs.     

Autonomic Responses to Affective Visual Stimuli

Thirty-two subjects were categorized by an objective questionnaire as high or low in fear of mutilation. These subjects viewed six slides each from three categories: neutral, incongruous, and mutilation. As predicted, fearful subjects' cardiac responses to mutilation were acceleratory and their counterparts' deceleratory. Both groups reacted to incongruous stimuli with heart rate deceleration. Unexpectedly, both samples displayed cardiac acceleration to the neutral category. Respiratory patterns of initial expiration characterized low-fear subjects whereas inspiration was typical in the high-fear group. However, respiratory activity did not vary over slide types. The high-fear sample emitted electrodermal responses of greater amplitude and slower recovery to mutilation slides than to the other categories. In both respects, the high-fear sample exceeded their counterparts. Finally, fearful subjects exhibited a more pronounced tendency to judge mutilation slides more aversive than incongruous or neutral materials. In general, responses to mutilation materials indicated reactions of defense in fearful subjects and orientation in low-fear persons.     

Individual Differences in Fear and Autonomic Reactions to Affective Stimulation

Klorman et al. (1975) found that mutilation-fearful persons reacted with heart rate speeding to mutilation slides and to neutral stimuli. The within-subject design of that study suggested that these paradoxical reactions to neutral slides may have been due to subjects' anticipation of phobic materials. In the present work, 84 female subjects, categorized by a standardized questionnaire as high or low in fear of mutilation, viewed one of three types of slides: 1) mutilated bodies; 2) persons and objects in incongruous or humorous poses; or 3) standard photographs of persons, objects, and landscapes. Mutilation materials evoked cardiac acceleration and high subjective tension in fearful subjects vs bradycardia and moderate tension in low-fear subjects. Neutral and incongruous slides prompted similar reactions from both fear groups: heart rate deceleration and low tension. Low-fear subjects shown mutilation slides tended to exceed the groups receiving nonaversive stimulation in magnitude of cardiac deceleration. Extensive analyses of respiratory activity showed that these differential heart rate reactions were not attributable to breathing. Mutilation stimuli evoked greater skin conductance responses than nonaversive slides, but there were no electrodermal differences as a function of fear relevance. The lawful relationship uncovered in the present research between cardiac reactions and individual differences in fear supports our suggestion that anticipation may have played a role in our earlier work.     

Sympathetic arousal moderates self-reported physiological arousal symptoms at baseline and physiological flexibility in response to a stressor in generalized anxiety disorder

Compared to controls, individuals with generalized anxiety disorder (GAD) often fail to exhibit expected changes in physiological arousal in response to laboratory stressors. Nevertheless, individuals with GAD often report significant subjective arousal. We sought to assess the degree of sympathetic arousal in individuals with GAD and controls and the impact such arousal had on self-reported physiological arousal and response to an emotional challenge. Degree of baseline sympathetic arousal moderated the self-report of physiological arousal in non-comorbid GAD at baseline such that within this group, higher levels of sympathetic arousal predicted reports of heightened physiological arousal compared to controls. Overall, individuals with GAD exhibited no significant changes in arousal in response to the emotional challenge. However, basal sympathetic arousal moderated degree of change such that non-comorbid GAD participants low in baseline sympathetic arousal exhibited changes in arousal similar to controls in response to the stressor. That basal sympathetic arousal moderated both self-reported arousal at baseline and sympathetic response to a stressor suggests important physiological heterogeneity in GAD, wherein only those individuals with heightened tonic sympathetic arousal report accompanying symptoms and display diminished sympathetic reactivity.     

Cortical and cerebellar modulation of autonomic responses to loud sounds

Detecting unexpected environmental change causes modulation of autonomic activity essential for survival. Understanding the neural mechanisms associated with responses to loud sounds may provide insights into the pathophysiology of posttraumatic stress disorder (PTSD), since individuals with PTSD exhibit heightened autonomic responses to unexpected loud sounds. We combined fMRI with autonomic psychophysiological assessment to investigate central and peripheral reactivity to loud tones in 20 healthy participants. Activity in anterior insula, pregenual anterior cingulate cortex, anterior midcingulate cortex, supplementary motor area, supramarginal gyrus, and cerebellar lobules VIII–IX was associated with both tones and concomitant skin conductance responses. Since regions signaling unexpected external events modulate autonomic activity, heightened loud tone autonomic responses in PTSD may reflect sensitization of this “salience” network.     

Individual Differences in Autonomic Response: Conditioned Association or Conditioned Fear?

Cluster analysis was used to define three groups of subjects whose conditioned heart rate response emphasized either acceleration, deceleration, or moderate deceleration. A subject pool (N = 148) was generated from four separate studies of differential classical conditioning in which colored slides served as conditioned stimuli (CSs) and the unconditioned stimulus (UCS) was aversive auditory noise. Both the statistically generated Accelerator and Decelerator groups responded with a significant late interval deceleration to CS+. However, only Accelerators also displayed a significant mid-interval heart rate increase to CS+. Conditioned electrodermal responses were significantly more resistant to extinction for Accelerators than for the other two cluster groups. Accelerators also differed from Decelerators in that their affective judgments of the slide stimuli became less positively valent and less dominant from pre- to post-conditioning, effects not found for Decelerators. Moderate Decelerators produced mixed results across the several psychophysiological and verbal measures of conditioning, resembling Accelerators in their verbal report change, and Decelerators in their rapid electrodermal extinction. It is suggested that cluster assignment may reflect subjects' pre-conditioning learning set. All successfully conditioned subjects appear to learn a relationship between stimuli such that the appearance of the CS+ prompts an anticipatory orienting response (late interval heart rate deceleration). Accelerators differ from the other two groups in that they also condition a defensive response which is associated with a change in emotional judgments of the stimuli and may represent covert preparation for avoidance. The relationships between defensive responding, avoidance, and the concept of fear are considered, and the problem of desynchrony in emotional change (i.e., the Moderate Decelerators) is addressed. Finally, parallels are drawn between results from classical conditioning and clinical studies of fear and phobia, and further suggestions are made for utilizing the conditioning paradigm in the study of emotion.     

Two‐year stability of individual differences in (para)sympathetic and HPA‐axis responses to public speaking in childhood and adolescence

Long‐term stability of individual differences in stress responses has repeatedly been demonstrated in adults, but few studies have investigated the development of stability in adolescence. The present study was the first to investigate the stability of individual differences in heart rate, parasympathetic (RMSSD, pNN50, HF), sympathetic (LF/HF, SC), and HPA‐axis (salivary cortisol) responses in a youth sample (8–19 years). Responses to public speaking were measured twice over 2 years. Stability was moderate for absolute responses and task delta responses of HR, RMSSD, pNN50, and HF. Stability was lower for SC and task delta responses of LF/HF and cortisol. Anticipation delta responses showed low stability for HR and cortisol. The latter was moderated by age or puberty, so that individual differences were more stable in more mature individuals. The results support the suggestion that stress responses may be reset during adolescence, but only for the HPA axis.     

Getting Individual Differences in Autonomic Reactivity to Work For Instead of Against You: Determining the Dominant "Psychological" Stress Channel on the Basis of a "Biological" Stress Test

The purpose of this study was to develop a procedure to increase the re liability of autonomic measures, such as skin conductance (SC) and heart rate (HR), when assessing negative emotional responding. The strategy was to capitalize on the individual difference factor by determining prior to the start of an experiment each subject's most reactive autonomic channel. To achieve this objective, a “biological” stress test (balloon-burst test) was used. Subjects were then classified by using a median-split, rank-ordered procedure, as high SC responders, high HR responders. high responders in both channels, or low responders in both channels. The generality of the responder-non-responder classification was then assessed to a “psychological” stressor which involved presentations of a fear-eliciting bodily-injury slide. Transfer effects were obtained with those subjects defined as high responders on a given channel displaying greater reactivity on that channel when compared to subjects classified as low responders. The implications of these findings for clinical research were discussed.     

Autonomic activity and baroreflex sensitivity in patients submitted to carotid stenting

Arterial baroreflex and cardiac autonomic control play important roles in hemodynamic instability after carotid artery stenting (CAS). Spontaneous baroreflex sensitivity (BRS), heart rate variability (HRV) and blood pressure variability (BPV) are established tools for the assessment of arterial baroreflex and cardiac autonomic activity. Aim of the study was to evaluate cardiac autonomic activity (by means of HRV, BPV and BRS) after CAS and to explore the impact of internal carotid artery stenosis on BRS changes after CAS. 37 patients (68±10.45 years) with internal carotid stenosis underwent CAS. HRV, BPV and BRS were measured in all subjects before and at 1 and 72h after CAS. ANOVA was performed to compare BRS, HRV and BPV parameters before and after CAS. Spearman analysis was performed to determine a possible correlation between carotid stenosis degree (or carotid plaque diameter) and BRS changes (ΔBRS). LF/HF (index of sympatho-vagal balance) decreased during postoperative period, in comparison with baseline (2.32±1.70 vs 1.65±1.40, p<0.05). There was a significant negative correlation between carotid stenosis degree and ΔBRS (r=-0.35, p=0.03) and between carotid plaques thickness and ΔBRS (r=-0.36, p=0.02). CAS procedure may cause an alteration of carotid wall mechanical properties, increasing baroreflex sensitivity. BRS does not increase in all the patients, because arterial wall damage and nerve destruction determined by atherosclerotic plaque may reduce ΔBRS.     

Cortical and Autonomic Arousal in Primary and Secondary Psychopaths

Abnormal offenders were classified as primary or secondary psychopaths, or as conforming or inhibited nonpsychopaths by means of empirically derived dimensions of psychopathy and social withdrawal. Measures of electrocortical, electrodermal, and cardiovascular activity were taken during rest, during repeated auditory stimulation, and during the cold pressor test. Psychopaths were not significantly differentiated from nonpsychopaths, but several differences were found between primary and secondary psychopaths. Primary psychopaths were more aroused cortically and electrodermally, and showed less rapid adaptation and habituation. Secondary psychopaths were the least aroused and showed signs of increasing drowsiness with repetitive stimulation. Secondary psychopaths in this study performed like primary or undifferentiated psychopaths in other reports, and possible explanations are discussed. The high arousal of primary psychopaths is not consistent with current theories of psychopathy, and attention to the relationship between psychopathy and the labelling of arousal is suggested.     

The Psychological Significance of Task-Induced Tonic Changes in Somatic and Autonomic Activity

Two experiments tested the view that task-induced autonomic-somatic gradient parallelism does exist and that the steeper the physiological gradients, over the course of a task, the more involved the subject and the greater the effort. Thirty-three male subjects performed easy and difficult versions of a continuous reaction time task. In both experiments the difficult task prompted steeper electromyographic (EMG) activity gradients than did the easy version. Scores on heart rate (HR) and skin conductance did not show clear gradients. However, task-dependent effort was positively related to the magnitude of the initial HR acceleration and to the steepness of the EMG gradient. The autonomic-somatic coupling hypothesis of Obrist did not explain the results. Instead, evidence for ventilatory-somatic parallelism was found.     

Moderate alcohol intake is related to increased heart rate variability in young adults: Implications for health and well‐being

Epidemiological literature indicates that the relationship between alcohol consumption and health outcomes reflects a J‐shaped curve such that moderate alcohol consumption confers a protective effect in comparison to abstinence, while heavy consumption is associated with poorer health. While heart rate variability (HRV) may underpin the relationship between drinking and poor health in heavy drinkers, it is unclear whether HRV is increased in moderate, habitual drinkers relative to nonhabitual drinkers. HRV and drinking habits were assessed in 47 volunteers. Results supported hypotheses suggesting that moderate, habitual drinking increases HRV. Although not supported by a significant interaction between drinking group and sex, planned follow‐up analysis also revealed that these findings may be specific to males. Regardless, results highlight HRV as a candidate mechanism for the findings reported in the epidemiological literature.     

Salivary alpha‐amylase changes promoted by sustained exposure to affective pictures

We studied the changes in salivary alpha‐amylase (sAA) and other psychophysiological indices (heart rate, skin conductance, and corrugator supercilii activity) elicited by sustained exposure to affective pictures. Thirty‐nine subjects viewed five blocks of pictures depicting mutilations, human attack, neutral scenes, sport/adventure, and erotica. Each block comprised 12 pictures of the same content. Saliva samples were collected before and after each block of pictures. The results showed that mutilation pictures promoted the greatest increase in sAA activity and output, as well as greater corrugator supercilii activity than pleasant pictures. Skin conductance response did not differ among high arousal picture contents. Changes in sAA varied with the affective valence but not with the arousal ratings of the pictures. Our results point to sAA as an index directly related to the unpleasantness elicited by sustained exposure to affective stimuli.     

Individual differences in electrodermal responsivity to predictable aversive stimuli and substance dependence

To determine if the inability to take advantage of the predictability of an aversive stimulus to diminish its psychological impact reflects a deficit in inhibitory control related to the development of substance dependence, we recorded skin conductance responses (SCRs), heart rate (HR), and anticipatory electrodermal nonspecific fluctuations (NSFs) from 175 16-18-year-old boys when a white noise blast was either unpredictable or temporally predictable. Compared with boys who had moderately reduced or augmented SCRs to predictable blasts (moderate and poor modulators, respectively), boys whose SCRs were greatly reduced (good modulators) had fewer symptoms of alcohol and nicotine dependence and more anticipatory NSFs. HR appeared to index an active coping response for good and moderate modulators. The autonomic response pattern evident for good modulators may index an inhibitory control mechanism protecting them from developing substance dependence.