Comparison of Frontal EMG Biofeedback and Several Types of Relaxation Instructions in Reducing Multiple Indices of Arousal

During the training phase, 96 subjects were given one of four types of relaxation instructions (single instructions, repeated instructions, relaxation training, no instructions) and in addition either did or did not receive frontal EMG biofeedback training. Results indicated that each of the instructions and biofeedback procedures were equally effective in reducing frontal EMG, but that none of these procedures had any effect on subjective anxiety or autonomic indices of arousal (pulse rate, skin temperature, and finger pulse volume). During the generalization/stress phase, subjects were threatened with electric shock and were told to apply the relaxation techniques they learned during the training phase even though no additional instructions and/ or biofeedback training would be provided. To assess the effectiveness of the shock manipulation, a no-threat control group was included. Results indicated that: a) the shock manipulation was effective in increasing arousal, b) previous instructions and/or biofeedback were equally effective in reducing frontal EMG levels, but that c) only relaxation training was consistently effective in reducing subjective and autonomic indices of arousal. These findings: a) suggest that in stressful situations, relaxation training may be more effective than either EMG biofeedback or simple relaxation instructions in producing a general relaxation effect as opposed to a specific EMG effect; and b) indicate the importance of assessing the effectiveness of relaxation procedures during stressful situations during which subjects’ levels of arousal are elevated above resting baseline levels.     

Temporal factors in sympatho-adrenomedullary activity following acute behavioral activation

Sixteen healthy male subjects performed a complex choice-reaction task under time pressure. Adrenaline and noradrenaline excretion, heart rate, and subjective reactions were measured before, during, and after the work period and at corresponding points in time in a control session without work. Mean adrenaline excretion, heart rate, and subjective arousal increased significantly during work and returned to baseline levels within 1–2 hr after the end of work. There were large inter-individual differences in the rate at which adrenaline output decreased. When subjects whose adrenaline output decreased rapidly were compared with those whose adrenaline output decreased slowly, it was found that ‘rapid decreasers’ had higher baseline levels of adrenaline, performed better on the choice-reaction task, and had lower scores in neuroticism. The significance of temporal factors in adrenaline-mediated adjustment to environmental stressors is discussed.     

Psychophysiologic Stress Responsivity in Type A and B Female College Students and Community Women

Extreme Type A and Type B women (Jenkins Activity Survey) randomly assigned to low or high stress conditions of a forced choice reaction time task were monitored for heart rate (interbeat intervals), pulse transit time, skin conductance levels, and skin conductance responses during baseline, task, and recovery periods. Participants included 41 female undergraduates (student sample) and 58 women aged 25-65 years (community sample). Multivariate repeated measures analysis of variance indicated that among the students, Type As exposed to high stress had significantly higher skin conductance levels at baseline than did the Type As in low stress. During the reaction time stress task, student Type As in high versus low stress exhibited both higher heart rates and more skin conductance responses, although these effects did not occur for Type Bs. After covarying the baseline physiologic indices, results revealed that both heart rate and skin conductance levels were significantly higher for students in high versus low stress, but the Behavior Type X Stress interaction disappeared. In contrast, the Behavior Type X Stress interaction remained for skin conductance responses. Findings in the community sample showed only a nonsignificant trend for higher heart rate in high stress Type As than in low stress Type As. These results provide very weak evidence for a relationship in physiological indices between Type A behavior and stress in women across a broad age range. Implications are discussed with regard to sex differences in behavior type and possible interactions between behavior type and stress responsivity.     

Differential effects of test stress on the heart rates of extraverts and introverts

A mental arithmetic task was administered to 39 subjects under conditions which imposed social stress. Using the relaxed state to provide a baseline, changes in heart rate and finger blood volume pulse were recorded. The subjects were divided to obtain groups with extreme scores on Eysenck's PEN scales, and the groups were compared on the two psychophysiological measures. Contrary to Eysenck's theory of Autonomic Lability as the neurological basis of N, the high N scoring group was not differentiated from the low N group by change in level of sympathetic activity as indicated by blood volume pulse, while, on the heart-rate measure, introverts showed a large increase and extraverts considerably less: there was no overlap between groups (p < 0.001). It was concluded that extraverts exhibit greater parasympathetic activity relative to sympathetic arousal under this stress condition.     

Difficulty and Instrumentality of Imminent Behavior as Determinants of Cardiovascular Response and Self-Reported Energy

College-aged male subjects were presented with an easy or moderately difficult memorization task and were told that they could earn either a very low or a very high chance of obtaining a modest prize if they did well. Cardiovascular (heart rate, systolic blood pressure, diastolic blood pressure) and subjective measures were taken during an interval immediately preceding the task performance period. Results indicated greater systolic blood pressure and self-perceived energy in the moderately difficult condition than in the easy condition only when the probability of attaining the prize (if subjects did well) was high. When the probability of goal attainment (given success) was low, systolic responses and self-reported energy levels were minimal in both task conditions. Predictions regarding the impact of energy levels upon goal attractiveness ratings were not supported, possibly for methodological reasons.     

Task Difficulty, Type A Behavior Pattern, and Cardiovascular Response

Forty-one young male subjects performed either an easy or moderately difficult arithmetic task with the opportunity to earn a monetary incentive if they did well. Cardiovascular (heart rate, systolic and diastolic blood pressure) and subjective responses were assessed immediately prior to and 5 min following task performance. Results indicated greater systolic (SBP) responses during the Pre-task period for subjects expecting to perform the difficult task. Behavior pattern classifications based on the Jenkins Activity Survey revealed Higher Pre-task heart rate (HR) elevations among Type As compared to Bs in the Difficult task condition, and greater Pre-task SBP responses in As compared to Bs irrespective of task difficulty. There also was some evidence of an association between SBP reactivity and scores on the Thurstone Activity scale. Change-scores reflecting SBP and HR reactivity were correlated in the Pre-task period of the Difficult but not the Easy condition. Predictions regarding the impact of motivational arousal upon goal attractiveness were not supported, possibly for methodological reasons.     

The effects of sleep inertia on decision-making performance

Sleep inertia, the performance impairment that occurs immediately after awakening, has not been studied previously in relation to decision-making performance. Twelve subjects were monitored in the sleep laboratory for one night and twice awoken by a fire alarm (slow wave sleep, SWS and REM sleep). Decision making was measured over 10 3-min trials using the ‘Fire Chief’ computer task under conditions of baseline, SWS and REM arousal. The most important finding was that sleep inertia reduces decision-making performance for at least 30 min with the greatest impairments (in terms of both performance and subjective ratings) being found within 3 min after abrupt nocturnal awakening. Decision-making performance was as little as 51% of optimum (i.e. baseline) during these first few minutes. However, after 30 min, performance may still be as much as 20% below optimum. The initial effects of sleep inertia during the first 9 min are significantly greater after SWS arousal than after REM arousal, but this difference is not sustained. Decision-making performance after REM arousal showed more variability than after SWS arousal. Subjects reported being significantly sleepier and less clear-headed following both SWS and REM awakenings compared with baseline and this was sustained across the full 30 min. In order to generalize this finding to real-life situations, further research is required on the effects of continuous noise, emotional arousal and physical activity on the severity and duration of sleep inertia.     

Cardiovascular effects of noise during complex task performance

Ten human subjects were stimulated with intermittent pink noise during the performance of a computerized task. Each subject received 3 consecutive sessions consisting of 10 min of baseline, 30 min of task performance, and 10 min of post-task baseline. Noise stimulation was presented during minutes 10-20 of task performance. Task performance was associated with significant increases in mean blood pressure, heart rate, and respiration rate and significant decreases in digital pulse amplitude. Noise stimulation was associated with a further decrease in digital pulse amplitude and a further increase in mean blood pressure. Noise- and task-elicited blood pressure and vasomotor responses did not habituate.     

Abdominal Temperature Changes During Male Sexual Arousal

The present study explored the feasibility of using temperature measurement from a non-genital location to assess sexual arousal. Based upon analyses conducted with thermographic techniques, it was hypothesized that abdominal skin cooling would occur during sexual arousal. In 2 sessions, 6 male subjects were shown low, moderate, and high arousing erotic films. Simultaneous measures of abdominal temperature, penile circumference, and subjective arousal were taken. Results indicate that while decreases in skin temperature were seen during arousal, thermister data did not correlate well with tumescence or subjective arousal ratings. It would appear that thermography and temperature measurement might be most fruitfully employed to explore basic physiological processes involved in sexual arousal, since continuous temperature measures do not appear sensitive enough for use in typical sex research paradigms.     

Habitual catecholamine excretion and its relation to habitual distress

In order to study interindividual differences in habitual subjective and physiological arousal a scale for measuring subjective arousal in the course of daily living was constructed and evaluated (the day-to-day stress scale, DtDSS) and urine samples for estimating free catecholamines were obtained on 17 occasions from each of 20 male subjects during a period of approximately 48 h. Samples were collected at home during daily activities and night rest, as well as under laboratory conditions, when periods of activity and inactivity alternated. The results showed: (1) that scores on the DtDSS correlated significantly with average adrenaline level, and (2) that low physiological reactivity was indicative of neuroticism.     

Cardiac awareness and autonomic cardiac reactivity during emotional picture viewing and mental stress

This study investigated the relationship between autonomic cardiovascular reactivity and cardiac awareness during the following conditions: baseline, emotional picture viewing, mental stress, and heartbeat tracking. Cardiac parameters were examined by using power spectrum analysis of heart rate variability and impedance cardiography. According to their performance in a heartbeat tracking task, 38 participants were classified as good (n=19) or poor (n=19) heartbeat perceivers. Neither group differed during baseline and heartbeat tracking, but good compared to poor heartbeat perceivers demonstrated greater sympathetic reactivity during mental stress and more vagal reactivity and subjective arousal during emotional picture viewing. The results suggest that cardiac awareness is related to greater responsivity of the autonomic nervous system during situations evoking autonomic reactivity.     

Anger expression, hostility, anxiety, and patterns of cardiac reactivity to stress.

The majority of studies investigating the relationships between psychological characteristics and cardiovascular reactivity to stress use a research strategy in which discrete traits are evaluated in isolation. The present study examined the effects of additive and/or interactive relationships among traits on cardiac reactivity to a mental arithmetic task. In addition, impedance cardiographic techniques were employed to examine potential relationships between such psychological traits and a specific measure--pre-ejection period (PEP)--of sympathic influence on the heart. Forty-nine undergraduate men performed a mental arithmetic task while continuous measures of PEP and interbeat interval (IBI) were collected. The subjects then completed questionnaires measuring anger expression, hostility, and trait anxiety. Analyses of variance (ANOVAs) showed a significant main effect for anger-out on PEP change from baseline, but not for IBI. Results also showed that anger-in interacted with anger-out and hostility to affect both PEP and IBI changes significantly. Other results indicated that subjects in the high anger-in/low anger-out and high anger-in/low hostility groups did not show significant PEP change, although they nevertheless showed significant IBI change. These results highlight the importance of the consideration of interactions among traits in predicting cardiac reactivity and of the importance of measuring specific indexes of sympathetic arousal.     

A startling absence of emotion effects: Active attention to the startle probe as a motor task cue appears to eliminate modulation of the startle reflex by valence and arousal

Research has shown that during emotional imagery, valence and arousal each modulate the startle reflex. Here, two imagery-startle experiments required participants to attend to the startle probe as a simple reaction time cue. In Experiment 1, four emotional conditions differing in valence and arousal were examined. Experiment 2, to accentuate potential valence effects, included two negative high arousal, a positive high arousal and a negative low arousal condition. Imagery effectively manipulated emotional valence and arousal, as indicated by heart rate and subjective ratings. Compared to baseline, imagery facilitated startle responses. However, valence and arousal failed to significantly affect startle magnitude in both experiments and startle latency in Experiment 1. Results suggest that emotional startle modulation is eclipsed when the probe is significant for task completion and/or cues a motor response. Findings suggest that an active, rather than defensive, response set may interfere with affective startle modulation, warranting further investigation.     

A Psychophysiological Exploration of Sexual Arousal Patterns in Females and Males

Fifty-nine female and 39 male undergraduates completed 3 sessions of a psychophysiological study on sexual arousal. Subjects were assigned to one of six experimental groups. Subjects within each group were exposed to a series of four audio-tapes, and were asked to fantasize before and after the tape series. Tapes varied in their erotic and romantic content, and two sex role dimensions were also varied across tapes. Dependent measures included scaled subjective reports, genital pulse amplitude and blood volume responses, heart rate, and finger pulse amplitude. Erotic contents were significantly more sexually arousing than nonerotic contents for both sexes. Romantic content did not significantly enhance the facilitation of sexual arousal. Nontraditional sex roles were significantly more arousing for females, with a similar nonsignificant trend for males. There were significant correlations between genital pulse amplitude and subjective reports of arousal; however, for females the genital blood volume measure showed less reliable agreement with subjective report. Genital pulse amplitude was the most reliable and precise indicator of arousal and accounted for the most variance across conditions. No significant changes occurred on the heart rate and finger pulse amplitude measures. Although subjects were able to become aroused by fantasy alone, listening to erotic tapes did not facilitate their ability to be sexually aroused during fantasy.     

Stress-related changes in financial risk taking: Considering joint effects of cortisol and affect

Many decisions under risk and uncertainty are made under physical or emotional stress. A recent meta-analysis suggested that stress reliably influences risk taking but did not find a relation between single measures of stress such as cortisol and risk taking. One reason for the conflicting findings could be that the influence of stress on risk taking depends not only on physiological but also on psychological stress responses, in particular affective valence. We tested this hypothesis in an exploratory empirical study: Seventy participants worked on a financial risk-taking task. In half of the participants acute stress was induced with a cold pressor task. For all participants we measured cortisol and α-amylase levels, blood pressure, subjective arousal, and affective valence before and after the task. The stress induction increased participants' levels of cortisol, subjective arousal, and systolic blood pressure but did not directly influence negative affect or risky decision making. Examining the interplay between physiological and psychological stress responses, a moderation analysis revealed an interaction between stress induction and affect valence: Negative affect predicted an increase in risk-seeking decision making in the stress condition, but not in the control group. A similar moderation was found with cortisol reactivity, that is, negative affect predicted an increase in risk-seeking decision making in participants with high cortisol reactivity but not in participants with low cortisol reactivity. These results suggest that the effect of stress on risky decision making depends on the interplay of affective valence and cortisol reactivity.     

The role of perceived control in physiological reactivity: self-efficacy and incentive value as regulators of cardiovascular adjustment

The aim of this study was to verify the influence of self-efficacy and incentive value on cardiovascular reactivity. Ninety-six subjects were randomly assigned to four experimental groups in each of which the self-efficacy (high or low) and incentive value (high or low) were modified in relation to a mental arithmetic task. Subjects were led to believe that failure in this behaviour would result in the appearance of an aversive stimulus. Heart rate, systolic and diastolic blood pressure, pulse pressure and skin temperature were all recorded throughout task performance, and at two given moments prior to the task, in order to establish baseline values. Subjects with high self-efficacy experienced a smaller increase in heart rate and systolic pressure, a greater increase in diastolic pressure, greater reduction in skin temperature and a reduction in pulse pressure during task performance. The effects were moderated by the incentive value in such a way that the effects of self-efficacy on cardiovascular reactivity were stronger when the consequences of task failure were perceived as highly relevant (high incentive value).     

Electromyographic and affective responses of episodic tension-type headache patients and headache-free controls during stressful task performance

Thirty-four subjects meeting diagnostic criteria for episodic tension-type headache and 42 who rarely experienced headaches participated in two laboratory sessions in which cephalic electromyographic (EMG) activity, electrodermal activity, heart rate, and finger temperature were recorded. Subjects performed relaxation, choice reaction time, psychomotor tracking, voluntary muscle contraction, and cold pressor tasks. Headache subjects showed significantly greater EMG activity than controls during baseline and stressful task performance. During relaxation, both groups reduced EMG activity from baseline levels, and there was no significant difference in EMG level between the groups during relaxation. Headache subjects reported higher levels of subjective anxiety, depression, anger, and stress than controls. Headache subjects also reported higher levels of pain than controls, and headache subjects reported greater pain during stressful task performance relative to baseline and recovery periods.This research was supported by NIH Grant R01-NS-25114.     

A lasting post-stimulus activation on dorsolateral prefrontal cortex is produced when processing valence and arousal in visual affective stimuli

This paper introduces a new paradigm in the study of emotional processes through functional neuroimaging. We study whether the valence and arousal of visual stimuli influence neuroimaging of the evoked hemodynamic changes. Using functional near-infrared spectroscopy (fNIRS), we investigate evoked-cerebral blood oxygenation (CBO) changes in dorsolateral prefrontal cortex (DLPFC) during direct exposure to different emotion-eliciting stimuli ('on' period), and during the period directly following stimulus cessation ('off' period). We hypothesize that the evoked-CBO, rather than return to baseline after stimulus cessation, would show either overshoot or undershoot. The study includes 30 healthy subjects and a total of 9 stimuli, which consist of video-clips with different emotional content. The total sample of trials studied (270) is classified according to the valence and arousal ratings given by the subjects. Results show a more robust activation in DLPFC during the 'off' period than during the 'on' period, depending on the subjective degree of arousal given to the stimulus. Our findings provide the first fNIRS evidence showing that an increment in subjective arousal leads to activation in DLPFC which persists after stimulus cessation and this does not occur with non-arousing stimuli. Neuroimaging studies must consider the duration and affective dimensions of the stimulus as well as the duration of the scanning to specify how much of the recorded response is analyzed. Not accounting for this difference may contribute to confusion in the data interpretation.     

Pace variation and control of work pace as related to cardiovascular, neuroendocrine, and subjective responses

Two studies of paced and self-paced arithmetic performance are reported. Heart rate and blood pressure were recorded and ratings of subjective arousal obtained. In one of the studies, plasma levels of catecholamines and cortisol were determined. Under externally paced experimental conditions pace variation was found to be quantitatively related to changes in systolic and diastolic blood pressure, as well as to ratings of stress and irritation. This was not the case for heart rate or positively evaluated aspects of subjective arousal. Performance was better and ratings of stress and irritation were lower during self-paced than during paced work at a comparable work pace. In one of the studies the diastolic blood pressure increased less when subjects controlled the pace. Plasma catecholamines did not increase significantly during either externally or self-paced work, but adrenaline tended to increase during paced work. Our findings give partial support to the suggestion that personal control may attenuate sympathoadrenal activation and cardiovascular reactivity.