The Effects of Expectancy Upon Electrodermal Responses to Signaled Stimuli

The research evaluates the role of expectancy in determining magnitude of electrodermal response to a moderately loud noise. Main emphasis was upon comparisons of response magnitudes when the intensity received confirmed that which was expected and when the intensity received was different from that expected. Based on preliminary observations which suggested that response magnitudes shifted in a direction corresponding to stimulus intensity expected, the experiment varied direction of change and evaluated subjective intensity of stimuli received, as well as magnitude of electrodermal responding. Perceived intensities of the noise stimuli were influenced by the direction of shift in the same fashion as electrodermal response magnitudes. Examination of factors determining electrodermal responses to the noises showed several contributing variables: the direction of shift from expectation, the subjective intensity of stimuli, and the amount of anticipatory electrodermal activity just prior to noise onset.     

Electrodermal lability as an indicator for subjective sleepiness during total sleep deprivation

The present study addresses the suitability of electrodermal lability as an indicator of individual vulnerability to the effects of total sleep deprivation. During two complete circadian cycles, the effects of 48h of total sleep deprivation on physiological measures (electrodermal activity and body temperature), subjective sleepiness (measured by visual analogue scale and tiredness symptom scale) and task performance (reaction time and errors in a go/no go task) were investigated. Analyses of variance with repeated measures revealed substantial decreases of the number of skin conductance responses, body temperature, and increases for subjective sleepiness, reaction time and error rates. For all changes, strong circadian oscillations could be observed as well. The electrodermal more labile subgroup reported higher subjective sleepiness compared with electrodermal more stable participants, but showed no differences in the time courses of body temperature and task performance. Therefore, electrodermal lability seems to be a specific indicator for the changes in subjective sleepiness due to total sleep deprivation and circadian oscillations, but not a suitable indicator for vulnerability to the effects of sleep deprivation per se.     

The Effect of Repeated Tense-Release Sequences on EMG and Self-Report of Muscle Tension: An Evaluation of Jacobsonian and Post-Jacobsonian Assumptions About Progressive Relaxation

This study tested three psychophysiological hypotheses generated from assumptions underlying post-Jacobsonian progressive relaxation techniques and assumptions that conflict with the rationale for Jacobson's progressive relaxation method. Twenty-eight subjects tensed and released tension from the forearm extensor and frontalis muscles during a series of trials interspersed with intervals of relaxation. Correlations between self-report of tension and EMG were moderate during relaxation, but did not increase across successive tense-release trials, thus indicating no increase in self-awareness of muscle tension. As predicted by Jacobson, paying attention to either muscle produced increased tension in the frontal area, but Jacobson's prediction of increases in forearm tension while paying attention to the forearm was not confirmed. Evidence was equivocal for the existence of the “pendulum effect” predicted by Bernstein and Borkovec. Tense-release trials produced gradual decreases in frontal EMG, but no changes in forearm EMG. Declines below baseline in self-reported muscle tension occurred only several minutes after the end of the tense-release trials, and did so for the forearm despite lack of EMG decreases in that area. This finding may reflect the influence of cognitive rather than muscular processes.     

THE EFFECT OF PRESTIMULUS VARIABILITY UPON PHYSIOLOGICAL REACTIVITY SCORES

In an attempt to improve the scoring of physiological responses, in terms of higher inter-correlations of physiological variables and correlations with self-report measures of mood change, three new scores were compared with Autonomic Lability Scores. The first score was produced by changing the sampling of physiological records to minimize spontaneous fluctuations. This increased the physiological-mood correlations. The second and third scores provided, additionally, corrections for individual prestimulus variability. Such corrections, done by covariance adjustment, tended to increase the physiological-mood correlations further. When done by a division procedure, no improvements were observed. None of the three scoring methods affected substantially the inter-correlations of physiological variables. Heart rate, skin conductance, and forehead muscle tension were measured during two stimuli: a noxious movie and a mild noise.     

The Relationship of Symptomatology and Medication to Electrodermal Activity in Schizophrenia

An electrodermal assessment procedure using mild innocuous tones, task-relevant tones, and loud white noise was administered to a sample of schizophrenic patients (n = 77). The present study investigated the relationship of schizophrenic symptomatology and anticholinergic level of neuroleptic medication to electrodermal variables. Each patient was evaluated for positive (florid) and negative (defect) symptoms. The neuroleptics that patients received were rated according to their anticholinergic effect. No significant differences in symptomatology were observed between electrodermal responders and nonresponders; however, nonresponders showed a nonsignificant tendency to have more positive and negative symptoms than responders. Both negative symptoms and anticholinergic levels were significant predictors of lower tonic levels of skin conductance. Patients receiving high anticholinergic neuroleptics showed significantly reduced measures of electrodermal responsivity and tonic levels. Thus, both symptomatology and type of neuroleptic are related to electrodermal measures, with the anticholinergic effect of neuroleptic medication being more pronounced.     

Subject expectancy effects in frontal EMG conditioning

The influence of subject expectancies on performance has been examined extensively within the framework of behavior therapy but has received little attention within the context of EMG training. This study assessed the effects of subject expectancy on acquisition during frontal EMG conditioning. Prior to conditioning, subjects were either given no expectancy or instructed that learning to control the feedback stimulus would be either easy (high expectancy) or difficult (low expectancy). Subjects in the three expectancy conditions then underwent 20 min of contingent reinforcement for frontal EMG decreases. Three similar groups of no, low, or high expectancy subjects received noncontingent reinforcement. Differential EMG behavior was exhibited between the two no-expectancy groups, with the contingent group reliably lower in EMG activity than that noncontingent. However, differences were not observed between contingent and noncontingent subjects given either low or high expectancy sets. None of the groups could be differentiated on the basis of subjective variables such as anxiety, relaxation, or frustration. These findings suggest that subject expectancies, either positive or negative, interfere with the acquisition of conditioned EMG behavior.     

The effect of cognitive reappraisal on physiological reactivity and emotional memory

We investigated the effect of cognitive reappraisal on emotional arousal, facial expressivity and subsequent memory. Men and women viewed emotionally negative pictures while they attempted to either increase or decrease negative emotions elicited by the pictures, or to simply view the pictures. Neutral pictures were also presented with instructions to simply view the pictures. Concurrent changes in emotional arousal and valence were assessed with skin conductance responses (SCRs) and facial corrugator electromyographic responses (EMG), respectively. Picture memory was assessed with an immediate recall test and a delayed recognition test. Relative to simply viewing pictures, voluntary reappraisal to increase negative emotion generated greater facial corrugator EMG and SCR responses, and reappraisal to decrease negative emotion generated decreased corrugator EMG responses. Men showed enhanced recognition for pictures presented during the increase and decrease conditions, whereas women showed comparable recognition performance across all regulation conditions. The modulation of subsequent recognition memory associated with decreasing emotion was inversely associated with changes in physiological responses. Our results suggest that sex is an important factor to consider in determining how reappraisal-induced physiological changes are associated with subsequent changes in memory. These findings contribute to our understanding of how reappraising emotion exerts both immediate and enduring influences on physiological responses and subsequent memory.     

Lack of Correlation Between Frontalis EMG and Either Neck EMG or Verbal Ratings of Tension

Eight normal subjects were trained with the aid of EMG feedback to successively increase and decrease the activity of the frontalis muscle on 5 consecutive days. Along with the activity of the frontalis, sternomastoid EMG was recorded from 4 subjects and EMG from both the semispinalis and splenius capitus was recorded from the other 4 subjects. Estimates of the degree of subjective tension or relaxation were obtained following Baseline, Increase Frontalis, and Decrease Frontalis periods on each treatment day. Frontalis EMG activity showed significant increases and decreases relative to baseline levels during appropriate periods. Sternomastoid EMG did not change significantly during either Increase Frontalis or Decrease Frontalis periods. Semispinalis/splenius EMG activity also did not change during Increase Frontalis periods, but increased significantly during Decrease Frontalis periods. Subjects’estimates of subjective tension increased above baseline during increases in frontalis EMG activity, but did not change significantly during decreases in frontalis EMG. These data support the findings of Alexander that changes in frontalis EMG neither generalize to other somatic muscles nor correlate with verbal reports of cognitive tension or relaxation.     

Overhabituation and Dishabituation Responses as a Function of Stimulus Intensity and Amount of Overhabituation Training

Several important issues regarding overhabituation and its effects have been raised. Of particular interest are the effects of amount of overhabituation on responses during overhabituation, the existence of important individual differences in response frequency and amplitude during overhabituation, and the effect of varied amounts of overhabituation training and of stimulus intensity on test and dishabituation response amplitudes. In the present study, each of 108 subjects was randomly assigned to one of three overhabituation exposure conditions (60, 120, or 180 trials) and one of two auditory stimulus intensities (60 or 85 dB). After reaching a phasic electrodermal habituation criterion, each subject received the appropriate number of overhabituation presentations of the standard stimulus (SS), followed by a test stimulus and an additional SS (the dishabituation stimulus). Results showed significantly higher frequencies and amplitudes of electrodermal responses to tonal stimuli with increasing numbers of overhabituation trials, but no significant changes over trial blocks. Individual differences were found. Subjects in a group defined by numerous overhabituation responses showed slower habituation, larger responses and higher frequencies of nonspecific responses during overhabituation, and larger test responses. Finally, the amplitude of test responses increased with increasing length of overhabituation and with increased intensity.     

Electrodermal Responsivity in Young Hypotensive and Hypertensive Men

Electrodermal responses were recorded during the presentation of 16 moderately intense (1000 Hz, 90dB) tones in three groups of young men: borderline hypertensives (138/79 mmHg), normotensives (112/65 mmHg), and hypotensives (104/63 mmHg). Electrodermal response habituation was measured as a decline in response over trials, number of trials to a response criterion of three successive nonresponses, and number of inversions of response amplitude (larger responses following smaller responses) in the stimulus sequence. Habituation was fastest in hypotensives. Nonspecific electrodermal responses at rest and during tone presentations were most frequent in borderline hypertensives, least frequent in the hypotensive group, with the normotensive group falling in between. There were no significant differences in electrodermal level. The rapid habituation rate in hypotensives is discussed in terms of cursory information processing associated with impulsive behaviour. The higher nonspecific electrodermal activity in borderline hypertensives is interpreted to indicate increased sympathetic nervous system activity.     

Psychophysiological stress and emg activity of the trapezius muscle

Although it is generally assumed that mental stress induces muscular tension, the experimental data have, so far, been inconclusive. Likely explanations for these inconsistent findings are (a) too small subject samples in some experiments, (b) the use of only one type of stress stimulation, and (c) the lack of objective (physiological) measurements documenting the stress-inducing properties of the experimental treatment. Furthermore, the effect of mental stress and physical load separately, versus the combined influence of physical and mental load on muscular tension, has not been investigated earlier. Therefore. the aim of the present experiment was to examine the effects of mental stress as well as of physical load, separately and in combination, on perceived stress, physiological stress responses, and on muscular tension as reflected in electromyographical (EMG) activity of the trapezius muscle. Sixty two female subjects were individually exposed to mental arithmetic, the Stroop color word test (CWT), the cold pressor test, standardized test contractions (TCs), and the CWT combined with a TC. Compared to baseline, the stress session induced significant increases in systolic and diastolic blood pressure, heart rate, urinary catecholamines, salivary Cortisol, and self-reported stress. Each of the two mental stress tests induced a significant increase in EMG activity, The CWT caused a rise in EMG activity also during the TC, which was significantly more pronounced than the increase induced by the CWT alone. Blood pressure responses and self-reported stress followed the same pattern as the EMG activity. The results are consistent with the assumption that psychological stress plays a role in musculoskeletal disorders by increasing muscular tension both in low-load work situations and in the absence of physical load. It is also indicated that the stress-induced increase in muscular tension is accentuated on top of a physical load. This study was supported by grants from the Swedish Council for Research in the Humanities and Social Sciences and the Swedish Work Environment Fund.     

Intact physiological response to arousal with impaired emotional recognition in alexithymia

BACKGROUND: The purpose of the present study was to clarify the relationship between the recognition of emotion and physiological response to emotion (i.e. arousal) in alexithymia. METHODS: This study investigated differences in physiological arousal state, as measured by continuous heart rate, electrodermal activity (EDA) and self-reported emotional intensity before and after exposure to an emotionally arousing or neutral videotape among 41 high- or low-alexithymic young adult participants. RESULTS: Across subjects, emotionally negative stimuli produced increased physiological arousal. However, high-alexithymic participants exposed to the arousing videotape did not report increased subjective emotional intensity, as did low-alexithymic participants. In addition, the baseline EDA of high-alexithymic participants was significantly higher than that of the low-alexithymic participants. CONCLUSIONS: Results support the prediction that alexithymia leads to a decoupling between subjective and physiological arousal when exposed to emotionally negative stimuli. This decoupling may increase alexithymic individuals' risks for stress-related illness.     

Effects of afternoon naps on physiological variables performance and self-reported activation

Fluctuations in physiological variables resulting from naps and the relationship of these to previously studied changes in performance and subjective activation associated with napping were examined. The subjects were eighteen healthy male university students who habitually slept $\text{1}\text{2}\text{?2}\text{hr}$ in the afternoon. Measurements were obtained of four physiological variables, from a continuous 10-min auditory reaction time task and two factors of an Activation Deactivation Adjective Checklist 20 min before and after a control condition and two electroencephalographically recorded afternoons of sleep. The experimental conditions comprised a 2-hr period of wakefulness, a $\text{1}\text{2}\text{hr}$ nap from 4.35–5.05 p.m., and a 2-hr nap from 3.05–5.05 p.m. Following each sleep treatment, when compared with the control condition, there were statistically significant shifts of improved reaction time performance, and elevated activation as reflected by the two self-report scales, increased EEG frequency, heart rate, and electrodermal responses. The shifts of increased behavioral efficiency, subjective and physiological activation were approximately equivalent in extent between 2-hr and $\text{1}\text{2}\text{-}\text{hr}$ naps. These findings indicate that besides the previously reported facilitation by naps of performance and mood, physiological activation is increased following accustomed episodes of afternoon sleep.     

The effect of changes in facial muscle tension on respiratory resistance

The relationship between changes in facial electromyographic (EMG) levels and respiratory resistance was examined. Thirty adult males were assigned equally to 1 of 3 groups; a facial muscle tension increase group (EMG increase), a facial tension decrease group (EMG decrease), and a noncontingent group (EMG noncontingent). Biofeedback procedures, based on EMG recordings made form electrodes positioned over the frontalis muscles, were used to effect muscle tension changes. Individuals in the EMG increase group exhibited increases in facial tension, but individuals in the EMG decrease group failed to show muscle tension changes. Respiratory resistance increased in individuals in the EMG increase group but did not change in individuals in the EMG decrease group. Like the EMG decrease group subjects, EMG noncontingent group subjects changed neither in facial tension nor in respiratory resistance. The results provided some support for a hypothesis linking facial muscle tension and respiratory resistance.     

The impact of cardiac perception on emotion experience and cognitive performance under mental stress

Mental stress evokes several physiological responses such as the acceleration of heart rate, increase of electrodermal activity and the release of adrenaline. Moreover, physiological stress responses interact with emotional and behavioral stress responses. In the present study we provide evidence that viscero-sensory feedback from the heart (cardiac perception) is an important factor modulating emotional and cognitive stress responses. In our study, we compared participants with high versus low cardiac perception using a computerized mental stress task, in which they had to respond to rapidly presented visual and acoustic stimuli. Additionally, we assessed physiological responses (heart rate, skin conductance). Participants high in cardiac perception reported more negative emotions and showed worse task performance under the stressor than participants low in cardiac perception. These results were not moderated by physiological responses. We conclude that cardiac perception modulates stress responses by intensifying negative emotions and by impairing cognitive performance.     

Biofeedback in the treatment of anxiety disorders

Studies which have used various forms of biofeedback in the treatment of anxiety disorders are summarized and examined in regard to whether biofeedback-mediated physiological changes are responsible for reductions in subjective reports of anxiety. The evidence suggests that frontal EMG biofeedback training to reduce muscle tension is the most promising biofeedback training technique to date. Studies of heart rate and EEG alpha biofeedback offer only minimal support for the use of these methods to facilitate anxiety reduction. The limited literature on the application of skin resistance level, finger pulse volume, and temperature biofeedback in the treatment of anxiety disorders suggests that these may be viable treatment techniques. The role of factors other than physiological change that may render biofeedback a successful treatment are discussed.     

Psychophysiological response patterns to positive and negative film stimuli

The aim of the present study was to investigate differential emotional response patterns to film stimuli by multimodal assessment of mood ratings, perception of bodily sensations, salivary cortisol, autonomic variables and facial electromyogram (EMG). Film stimuli, chosen to elicit positive and negative emotional states, were presented to 12 subjects with general anxiety disorder and 12 controls. Changes in mood, bodily sensations, autonomic activity (heart rate, respiration rate and skin conductance), facial EMG activity (corrugator and zygomatic muscle region) and salivary cortisol were measured. Analyses revealed differential changes in all response systems except for respiration rate and salivary cortisol. Although high-anxious subjects did not differ from controls in their average responses to the negative film stimuli, there is a tendency of a greater coherence of emotional response components in generalized anxiety subjects. However, spontaneous facial expressions to positive and negative film stimuli were associated with augmented electrodermal activity within both groups. Results are interpreted in light of directional response fractionation, dimensional approaches of emotion, and the facial feedback literature.     

Drug-related information generates placebo and nocebo responses that modify the drug response

OBJECTIVE: Administration of the muscle relaxant carisoprodol and placebo was crossed with information that was agonistic or antagonistic to the effect of carisoprodol. It was investigated whether information alone induced physiological and psychological responses, and whether information modified the response to the drug. METHODS: Half of the subjects received capsules containing 525 mg carisoprodol together with information that the drug acted in a specific way (Groups Relaxant/C, Stimulant/C, and No Information/C). The other half of the subjects received lactose (Groups Relaxant/L, Stimulant/L, and No Information/L). Dependent variables were blink reflexes and skin conductance responses, subjective measures of tension and sleepiness, and serum carisoprodol and meprobamate concentrations. Recordings were made between 15 and 130 minutes after administration of the capsules. RESULTS: The Stimulant/L group reported more tension compared with the other two groups, and carisoprodol increased tension even more in the Stimulant/C group. The Relaxant/C group displayed higher levels of carisoprodol serum concentration compared with the other groups that received carisoprodol. CONCLUSIONS: Reported tension was modulated in the direction suggested by the stimulant information. The effect of carisoprodol on tension was also modulated by stimulant information. Increased carisoprodol absorption in the group that received relaxant information could be a mechanism in the placebo response.     

Paranoid-nonparanoid differences--psychophysiological parallels.

It was predicted that the psychological differences between paranoids and nonparanoids would be parallelled by differences in psychophysiological responses to stimuli varying along both informational and motivational dimensions. Skin conductance and heart rate responses to stimuli in a guessing task were measured in a group of paranoid patients and compared with those from non-paranoid and non-patient controls. A group of nonschizophrenic patients on phenothiazine medication served as drug-matched controls. Skin conductance level, response frequency and amplitude data are reported; heart rate response changes were examined by means of times series analysis and reported as first and second deceleration and first and second acceleration components. It was predicted that paranoid patients would show a greater increase in skin conductance measures with cognitive demand, and an increase in acceleratory components of the heart rate to increases in motivational variables. The normal pattern of greater electrodermal responding to the negative stimuli than the positive, and greater heart rate acceleration to the positive stimuli but not the negative (Fowles, 1980) was predicted to be reversed in schizophrenic patients, and possibly more marked in paranoids. Cognitive manipulations showed the predicted increase in electrodermal and heart rate responding in normal controls. The paranoid subjects showed a similar increase as a function of task demands, but there was no significant difference between the other groups. Motivational manipulations produced increased skin conductance responding and increases in heart rate acceleration components in normal controls, this was not parallelled in the patient groups. All subject groups failed to show greater electrodermal activity to negative than to positive stimuli. Normal controls showed significant heart rate acceleration to positive as compared to negative stimuli, this pattern was reversed in paranoid patients.     

The influence of frontal alpha‐asymmetry on the processing of approach‐ and withdrawal‐related stimuli—A multichannel psychophysiology study

The approach‐withdrawal model of hemispheric activation suggests that left frontal cortical areas mediate approach, while right frontal cortical areas mediate withdrawal motivation. Within this framework, the present study investigates the association of frontal cortical asymmetry with attentional and emotional responses toward approach‐ and withdrawal‐related emotional stimuli. Resting frontal asymmetry was measured from 43 students before they passively viewed negative, neutral, and positive emotional pictures. The startle reflex, skin conductance response, and subjective ratings of valence and arousal were assessed to quantify emotional responding, while attention was assessed with ERPs. We also assessed frontal asymmetry in response to the pictures. Results indicated that relatively stronger right frontal cortical activation was associated with increased N1 amplitudes and more negative subjective emotional evaluation of all stimuli. Furthermore, enhanced right frontal asymmetry (state and trait) was associated with diminished emotional modulation of the late positive potential. In contrast, no association of frontal asymmetry with defensive reflex physiology or activation of sympathetic nervous system activity was found. The current data suggest dissociable influence of resting frontal brain asymmetry on attentional and physiological processing of withdrawal‐ and approach‐related stimuli. That is, asymmetrical frontal cortical brain activation might not modulate approach‐/withdrawal‐related motor responses and sympathetic arousal directly, but instead enhances allocation of attentional resources to subjectively significant stimuli. The results are discussed in terms of their potential importance for emotion perception in anxiety disorders and their contribution to the understanding of frontal asymmetry.