Autonomic reactivity during viewing of an unpleasant film.

The effect of an aversive, high-arousing film on heart rate, respiratory sinus arrhythmia, and electrogastrographic activity (EGG) was investigated. Previous studies have indicated a larger heart-rate deceleration for visual stimuli depicting surgery or blood compared to neutral content, and this phenomenon is similar to the bradycardia observed in animals in response to fear. The heart-rate deceleration is clearly parasympathetically driven, and it is considered a general index of attention. An accurate index of cardiac vagal tone can be obtained by means of quantification of the amplitude of respiratory sinus arrhythmia. The relationship between cardiac vagal tone and EGG is complex, but animal research has shown that suppressing vagal activity dampens gastric motility. We have investigated whether a movie depicting surgery is associated with greater heart-rate deceleration, larger increase in respiratory sinus arrhythmia, and greater increase in EGG activity compared to a neutral movie. In addition, if both respiratory sinus arrhythmia and EGG are indices of vagal tone, a positive correlation between these physiological responses was expected. Analysis indicated an effect of the surgery movie on heart rate and respiratory sinus arrhythmia, but not on EGG activity. Moreover, the expected correlation was not found. Implications for future studies are discussed.     

The Effect of Attentional Control and Heart-Period Variability on Negative Affect and Trait Anxiety

In this study, the author examines the effect of attentional control and heart-period variability on measures of negative affect and trait anxiety in undergraduate students. Baseline heart rate was recorded from 119 participants within a laboratory setting. Spectral analysis was used on the heart-rate data to isolate the parasympathetic contribution to the cardiac pattern. Participants completed measures of negative affect, attentional control, and trait anxiety following the recording of heart rate. Regression analysis indicated that high negative affect, low attentional control, and reduced parasympathetic tone were significant predictors of high trait anxiety. Subsequent regression analysis pointed toward the interaction of attentional control and parasympathetic tone in influencing self-rated measures of negative affect. Results highlight the importance of attentional control and parasympathetic tone as regulatory mechanisms related to self-rated estimates of negative affect and trait anxiety.     

Cardiac activity and information processing: the effects of stimulus significance, and detection and response requirements.

In two experiments, measures of heart rate and electromyographic activity were obtained from 40 male undergraduates while they performed two series of trials involving a sequential information processing task. Each trial consisted of a warning light, three successive tones, and a responded light, separated by 6-sec intervals. In Experiment 1, subjects responded only if the three tones were of different frequencies. Acclerative heart-rate responses to the last tone increased as a function of the significance of that tone. Subsequent cardiac decelerations were only observed if the subject was preparing to make a response. These results were replicated in Experiment 2, in which subjects responded only if two of the preceding tones were of the same frequency. Electromyographic activity was not significantly affected by stimulus significance or response anticipation. The data indicate that cardiac acceleration and deceleration reflect two independent psychological processes, associated with information-processing and decision-making activity on the one hand, and preparatory activity on the other.     

Influence of attention manipulation on emotion and autonomic responses

Psychopathologies such as depression and anxiety have been associated with self-consciousness, a trait focusing on the self in terms of emotions and social images. A technique designed to shift attention away from the self tends to reduce anxiety, so the present purpose was to assess the effect of self body-state information on an individual's emotional and autonomic activity. 24 undergraduate and graduate students (10 men and 14 women), ages 19 to 27 years (M = 22.1, SD = 2.5), were recruited as subjects. Focusing on body-state during an anxiety-inducing situation led to an increase of low to high frequency ratio of heart-rate variability which reflected cardiac sympathovagal balance. That is, attending to one's own bodily states enhanced relative sympathetic activity compared to parasympathetic activity, which can be interpreted as one of the physiological emotional responses elicited by anxiety.     

Reduced electrodermal activity in psychopathy-prone adolescents

This study tests the hypothesis that psychopathy-prone adolescents show reduced anticipatory skin conductance responding. Electrodermal activity was recorded while participants anticipated and responded to a 105 dB signaled or unsignaled white-noise burst. Using an extreme groups design, the authors used Child Psychopathy Scale (D. R. Lynam, 1997) scores from a community sample of 335 male adolescents (age 16) to form control (n = 65) and psychopathy-prone (n = 65) groups. Significantly more psychopathy-prone participants were nonresponders in the signaled anticipatory (p = .014), signaled responsivity (p = .037), and unsignaled responsivity (p = .003) conditions compared with controls. Anticipatory hyporesponsivity of psychopathy-prone adolescents similar to the electrodermal hyporesponsivity found in psychopathic adults suggests that this autonomic impairment is present by adolescence and may predispose individuals to adult psychopathy.     

Changes in heart rate during feedback control of respiration

Subjects received one of eight treatments: practice at increasing heart rate with heart-rate feedback, practice at decreasing heart rate with heart-rate feedback, practice at increasing heart rate without heart-rate feedback, practice at decreasing heart rate without heart-rate feedback, practice at increasing respiration rate with respiratory feedback, practice at decreasing respiration rate with respiratory feedback, practice at increasing respiration rate with respiratory instructions only, practice at decreasing respiration rate with respiratory instructions only. Heart rate, Respiration rate, and Respiration depth were measured. Analysis indicated that subjects who controlled respiration with respiratory feedback reliably increased and decreased heart rate; subjects who controlled respiration with respiratory instructions only reliably increased but not decreased heart rate; subjects in the respiratory-feedback conditions showed higher heart-rate increase and decrease than heart-rate increase and decrease of subjects in the other six conditions.     

Control of the temporal locations of polydipsic licking in the rat.

We studied the variables controlling the temporal location of polydipsic licking. Four rats were trained on a mixed fixed-ratio 10 (no tone) chained fixed-ratio 10 (no tone) fixed-ratio 90 (tone) schedule and on a multiple fixed-ratio 10 (tone) fixed ratio 100 (no tone) schedule. On the multiple schedule, drinking followed pellets if a fixed ratio 100 was upcoming for all four subjects and for two of the subjects if a fixed ratio 10 was upcoming. On the mixed schedule, drinking preceded the fixed-ratio 90 component of the chain. Two subjects also drank after pellet delivery on the mixed schedule before both the fixed ration 10 and the chain components. The number of licks was greater following a pellet than following a response. In a second phase with two of these subjects, the total response requirement of the chain was held constant at 100, while the size of the two ratios that constituted the chain was varied inversely. The tone signaled onset of the second link. Drinking followed the tone when it signaled fixed-ratio 90, 95, or 100 but not when it signaled fixed ratio 75, 80, or 85. These results show, on the one hand, that polydipsic licking is controlled by discriminative properties of the pellet rather than by its eliciting or "thirst-producing" characteristics. On the other hand, the fact that drinks were longer following a pellet than following a response suggests a contribution of thirst to polydipsia.     

Effects of short-term psychological stress on the time and frequency domains of heart-rate variability

The purpose of this study was to test the hypothesis that short-term psychological stress produces significant changes in sympathovagal activity. A simple, noninvasive method was used measuring the timing and frequency of heart-rate variability (HRV). 30 normal healthy subjects were assigned into two age- and sex matched groups. In the experimental condition a 5-min. psychological stress test, predominantly based on the Stroop Word Color Conflict Test, was employed in a competitive setting and included a financial inducement to produce psychological strain. Analysis showed that during psychological stress a significant reduction in the timing and frequency of heart rate variability was observed. The standard deviation of interbeat intervals decreased. A significant increase in heart rate was also observed. Within the frequency domain, a significant reduction in the high frequency component of HRV and a significant increase in the low frequency component were observed. There was also a significant increase in the low frequency to high frequency ratio. Self-evaluation of physical tension and emotional state measured by visual analog scales also showed significant increases following psychological stress. No significant differences were observed on any variables within the control group. The results indicate a shift towards sympathetic predominance as a result of parasympathetic withdrawal and demonstrates that this psychological stress test is effective in provoking a characteristic defence-arousal reaction. This simple, cost-effective method of analysing heart rate variability is suitable for detection of short-term changes in sympathovagal balance.     

The effect of unilateral stellectomy on the regulation of heart rate during behavioral stress.

Changes in heart rate were examined during classical aversive conditioning before and after either left (n = 10) or right stellectomy (n = 8). Heart rate (HR) significantly (p less than 0.01) increased in response to the conditional stimulus with a further increase noted during the unconditional stimulus. After right stellectomy (RSGx) the aversive stress elicited a significantly (p less than 0.01) smaller increase in heart rate (peak HR change: control 66.8 +/- 6.0; RSGx 36.1 +/- 6.8 beats/min). In contrast left stellectomy did not significantly alter the heart rate conditional response. Cardioselective beta-adrenergic receptor blockade, metoprolol HC1 (BB, 1.0 mg/kg, n = 8), significantly (p less than 0.01) reduced the heart-rate conditional response (peak HR change: control 66.8 +/- 6; BB 25.1 +/- 3.8 beats/min) to the same extent as noted during RSGx. These data suggest that the heart-rate increases elicited by aversive stress are mediated in part by sympathetic nerves that originate or pass through the right stellate ganglion. The residual HR increase noted after RSGx or BB probably results from the withdrawal of cardiac parasympathetic activity.     

The effect of unilateral stellectomy on the regulation of heart rate during behavioral stress

Changes in heart rate were examined during classical aversive conditioning before and after either left (n=10) or right stellectomy (n=8). Heart rate (HR) significantly (p<0.01) increased in response to the conditional stimulus with a further increase noted during the unconditional stimulus. After right stellectomy (RSGx) the aversive stress elicited a significantly (p<0.01) smaller increase in heart rate (peak HR change: control 66.8 +/- 6.0; RSGx 36.1 +/- 6.8 beats/min). In contrast left stellectomy did not significantly alter the heart rate conditional response. Cardioselective beta-adrenergic receptor blockade, metoprolol HCl (BB, 1.0 mg/kg, n=8), significantly (p<0.01) reduced the heart-rate conditional response (peak HR change: control 66.8 +/- 6; BB 25.1 +/- 3.8 beats/min) to the same extent as noted during RSGx. These data suggest that the heart-rate increases elicited by aversive stress are mediated in part by sympathetic nerves that originate or pass through the right stellate ganglion. The residual HR increase noted after RSGx or BB probably results from the withdrawal of cardiac parasympathetic activity.     

学前儿童迷走神经活动与情绪反应、情绪调节及冲动性的关系

Porges的多迷走神经理论提出迷走神经活动(vagal activity)与儿童的情绪及社会行为密切联系,已有研究探讨了儿童迷走神经活动与儿童的情绪反应及调节的关系,但研究结论不够清晰,需要进一步研究澄清。本研究选取93名4-6岁学前儿童被试,运用生理测量手段与呼吸性窦性心律不齐(respiratory sinus arrhythmia,RSA)分析的方法,采用父母报告的学前儿童情绪反应强度、情绪调节能力、冲动性为结果变量,进一步探讨儿童迷走神经活动(以基线RSA、RSA撤出、RSA恢复为指标)与情绪反应、情绪调节及冲动性的关系。研究发现:(1)基线RSA与儿童情绪反应强度显著负相关,与儿童情绪调节能力显著正相关,基线RSA是儿童情绪反应强度显著负向预测因子,是儿童情绪调节能力的显著正向预测因子;(2)RSA撤出、RSA恢复性与儿童冲动性显著负相关,是儿童冲动性显著负向预测因子。研究结果支持了Porges的多迷走神经理论,表明迷走神经活动与儿童情绪反应、情绪调节及冲动性密切联系。     

Anxiety, perception, and control of heart rate

8 women and 8 men took Cattell's IPAT-anxiety questionnaire and later McFarland's test of ability to perceive heart activity. The second test involved subjects' tracking their own heart rates, then they enrolled in an EKG biofeedback session to evaluate ability to increase and decrease heart rate from subjects' resting baselines. At the end of the session each subject completed Blanchard, et al.'s questionnaire to specify the cognitive strategies used for heart-rate control. Heart rate, abdominal respiration rate, respiration amplitude, EEG percent power in theta, alpha, and beta bands were evaluated. Success of heart-rate decrease seemed to depend mainly on activity levels: the subjects who achieved high scores on the activity test decreased heart rate significantly better than did low scorers. The relationship between scores for perception of heart and increases in heart rate was nonsignificant: increased heart-rate seemed to depend on differences in respiration between the rest and periods of increase. The significant, negative correlation between trait anxiety and perceptions of heart activity suggested that anxiety affected subjects' ability to perceive heart rate. The theta EEG power of the right hemisphere was significantly higher in subjects scoring high than for those low in perception of heart activity. During heart-rate increase tasks subjects mainly reported use of 'arousal responses,' similarly during heart-rate decrease tasks they reported use of relaxation responses.     

Role of feedback in voluntary control of heart rate.

The relative effectiveness of biofeedback techniques on the voluntary control of heart rate was examined by randomly assigning 32 Ss to one of four feedback conditions in a bi-directional heart-rate control task: (1) no feedback, (2) binary feedback--S was signaled when an interbeat interval had changed in the correct direction, (3) "real-time," proportional feedback--S was provided information about the relative duration of successive interbeat intervals, and (4) numerical, proportional feedback--each interbeat interval was represented as a numeral indicating its relationship to pre-trial mean by direction and magnitude. Significant over-all heart-rate changes were evidenced for both increase and decrease directions, but no differences were found between the feedback conditions. While these data suggest that feedback may be a relatively insignificant factor in voluntary heart-rate control, it was recommended that further investigation examine the role of feedback within the context of other training, mediating and motivational variables.     

Effects of an emotional negative stimulus on the cardiac, electrogastrographic, and respiratory responses

The experiment investigated the effects of two film sequences, one neutral and the other emotional, on the cardiac (ECG), electrogastrographic (EGG) and respiratory activities of 24 healthy students during digestion. The physiological activity was recorded before and during the projection of each film sequence. 12 subjects were shown a neutral film sequence and 12 an emotional film sequence. At the end of each viewing period, each subject completed a self-rating questionnaire on the emotional experience. Analysis indicated, with respect to the previewing (baseline) values, an increase in cardiac and respiratory rates and a decrease in electrogastrographic rates during the viewing of the film sequences. Changes in the EGG rate (baseline to viewing) were negatively correlated with the changes in ECG and respiratory rates, whereas the changes in these latter two were positively correlated. In comparing the effects of the neutral and emotional scenes the only significant result was the heart-rate increase in subjects watching the emotional sequence. Also, the self-rating of emotional experience varied with the emotional value of the sequence.     

Covert neuromuscular activity of the dominant forearm during visualization of a motor task

This study evaluated specific covert neuromuscular activity during a silent visualization exercise. 30 subjects participated in a dual-baseline single-subject procedure. The experimental test condition required the subjects to visualize themselves squeezing a hand-size rubber ball as tightly as possible for 1 min. In the comparison test condition, subjects were asked to imagine the 'sun setting on the horizon' for 1 min. Visualization of the motor task brought about significant (p <.05) increases in dominant forearm EMG (microV) and heart-rate activity (bpm) from rest to the experimental test condition. Nondominant forearm activity showed no significant changes from rest to either test condition, and heart-rate activity (bpm) showed no significant change from rest to the comparison visualization task.     

Instructional, pacing, and feedback control of respiratory behavior.

Procedures designed to affect respiration rate and amplitude were assessed for 4 groups of 8 subjects each. The groups were exposed to combinations of procedures providing feedback for decreasing respiration amplitude, pacing respiration rate, and instructions on rate and amplitude of breathing. After an initial baseline, effects were examined during both treatment and self-management phases for respiratory activity and concurrent heart-rate and electromyogram activity. Reliable effects of pacing on respiration rate, and a slight, but non-significant effect on amplitude were observed. No effects were observed for any heart-rate or electromyogram measures.     

Resilience and vagal tone predict cardiac recovery from acute social stress

Previous studies showed that heart period decreases during and recovers after an acute stress. We investigated if individual predispositions and emotional priming influence heart period recovery after a speech stress task. Psychometric scales and resting cardiac vagal tone were used to measure individual traits. The presentation of a sequence of either pleasant or unpleasant pictures, as emotional primers, preceded the speech stress. Heart period was measured throughout the experiment. Stress induced tachycardia irrespective of emotional priming or traits. In the recovery period, participants with higher resting cardiac vagal tone or presenting higher resilience significantly reduced the heart acceleration. Furthermore, these traits interacted synergistically in the promotion of the recovery of heart period. Pleasant priming also improved recovery for participants with lower negative affect. In conclusion, the stress recovery measured through heart period seemed dependent upon individual predispositions and emotional priming. These findings further strengthen previous observations on the association between greater cardiac vagal tone and the ability to regulate emotion.     

Time course of cardiac conditioned responses in restrained rats as a function of the trace CS-US interval

Two experiments aimed at understanding the temporal characteristics of trace-conditioned heart-rate responses to a 0.5-s tone (conditioned stimulus [CS]) in restrained rats. A CS paired with a tail-shock (unconditioned stimulus [US]) elicited lasting bradycardiac responses. The magnitude and extinction rate of conditioned responses (CR) were independent of the CS-US interval (interstimulus interval [ISI], 3 s to 20 s). Unreinforced test trials were analyzed for CR topography. Responding was delayed in groups with longer ISIs, but CR latencies, peak and decay times were not proportional to the ISI. Response peaks tended to cluster either about 6 s after CS onset, or about 10 s with a slow decay, depending on the ISI. The authors postulated 2 components of auditory stimulus traces involved in cardiac conditioning, maximally active 6 s and 10 s respectively after CS onset. The topography of the CR could be constrained to combinations of associative strength and instantaneous activity of these 2 components.     

Stimulus properties of facial expressions and their influence on the classical conditioning of fear

The influence of particular stimulus properties of facial expressions of emotion upon associative learning to a neutral cue was examined in the present investigation. A compound stimulus, composed of either a fearful, happy, or neutral facial expression paired with a neutral cue (tone), signaled an aversive event (mild electric shock). Phasic change in skin conductance (SC) was used as the measure of associative learning. Analyses of variance revealed that subjects who saw a fearful expression paired with the tone gave larger SC responses to the fearful expression than to the tone. The opposite pattern was obtained for subjects who had a happy expression paired with the tone. Subjects who had the neutral expression paired with the tone showed no significant difference in their responses to the two stimuli. Results of the present investigation were consistent with those of an earlier study by Lanzetta and Orr (1980), and extend the earlier theoretical interpretations by suggesting that fear expressions function as excitatory stimuli and happy expressions act as inhibitory stimuli. Methodological changes in the present study, which include a shorter CS interval and asynchronous stimulus onsets, also extend the previous findings.This research was supported by National Science Foundation Grant No. 7912422-AO1 and by funds from the Lincoln Filene endowment to Dartmouth College.     

Yoga-based guided relaxation reduces sympathetic activity judged from baseline levels

35 male volunteers whose ages ranged from 20 to 46 years were studied in two sessions of yoga-based guided relaxation and supine rest. Assessments of autonomic variables were made for 15 subjects, before, during, and after the practices, whereas oxygen consumption and breath volume were recorded for 25 subjects before and after both types of relaxation. A significant decrease in oxygen consumption and increase in breath volume were recorded after guided relaxation (paired t test). There were comparable reductions in heart rate and skin conductance during both types of relaxation. During guided relaxation the power of the low frequency component of the heart-rate variability spectrum reduced, whereas the power of the high frequency component increased, suggesting reduced sympathetic activity. Also, subjects with a baseline ratio of LF/HF > 0.5 showed a significant decrease in the ratio after guided relaxation, while subjects with a ratio < or = 0.5 at baseline showed no such change. The results suggest that sympathetic activity decreased after guided relaxation based on yoga, depending on the baseline levels.