Greater Skin Conductance Responses Research Articles

Intolerance of Uncertainty is Associated with Heightened Arousal During Extinction Learning and Retention: Preliminary Evidence from a Clinical Sample with Anxiety and Obsessive-Compulsive Disorders

Abstract Background Uncertainty-related distress is considered a hallmark of anxiety and obsessive compulsive disorders (OCD). Previous research in community samples has demonstrated that individuals with high Intolerance of Uncertainty (IU), the tendency to find uncertainty aversive, display altered threat extinction learning and retention. Methods Here, we conducted an exploratory secondary analysis of an existing dataset (Steinman et al., 2022) to examine the extent to which IU in a clinical sample with anxiety and OCD predicts threat extinction learning and retention. Participants with an anxiety disorder and/or OCD completed a differential threat learning task across two days (n = 27). Skin conductance response (SCR) was used as an index of conditioned responding. Results No significant effects of self-reported IU were observed for differential SCR during any of the experimental phases. However, higher self-reported IU, while controlling for trait anxiety, was specifically associated with greater SCR overall during same-day extinction training, next-day extinction training, and next-day reinstatement test. Conclusions Such findings provide preliminary evidence that higher IU within clinical samples with anxiety and/or OCD may be associated with heightened arousal under uncertainty, and highlight IU as a promising treatment target for anxiety and OCD.

Role of expectancy in physiological responses to sound recognition of musical dissonance and timbral change

Recently, it has been suggested that tonal violations produce greater skin conductance response (SCR) than timbral violations in music listening. However, it is unknown how people focus their attention during musical excerpts. The aim of this study is to replicate previous research considering two psychophysiological mechanisms: prediction error and brain stem reflex. Twenty-seven nonmusicians were instructed to listen six melodies and detect three altered conditions in one note: a dissonance (note out-of-key), a timbral change, and dissonance which changes in timbre and tone ( timdis). Amplitudes of SCR, heart rate (HR), and respiration rate (RSPR) were analyzed. In addition, the frequency of SCR and the percentage of musical events detection were measured. Results showed no significant differences either on amplitude of SCR or on respiratory rate. However, perception of timdis produced an increase in HR higher than dissonance ( p < .05) and the timbre condition had a higher frequency of SCR than dissonance ( p < .05). In addition, participants only detected 59.3% of dissonances but they were aware of 90% of notes in-key ( original melody). Finally, there was no significant correlation between percentage of detection and frequency of SCR. Results are discussed based on the prediction error mechanism, a theoretical model of expectation.

Preferential snake detection in a simulated ecological experiment

According to Isbell's snake detection theory (SDT), the need to rapidly detect and thus avoid snakes had a major impact on the evolution of the primate visual system, and thus the origin and evolution of the primate lineage, as expansion of the visual sense is a key characteristic of primates. The SDT rests on the assumption that there are both cortical (conscious) and subcortical (unconscious) brain structures and pathways that are responsible for rapid visual detection of and quick avoidance reactions to snakes. Behavioral evidence for the SDT primarily comes from visual search tasks and presentations of images on a computer screen; our aim was to evaluate the SDT under more ecologically valid circumstances. We asked participants to take a virtual hike in which a realistic model of a snake, rabbit, or bottle had been placed on the trail. Subjects were instructed simply to imagine themselves as the hiker while watching the video. We measured heart rate and skin conductance reactions while the participants viewed the video. After the video, the participants were shown pictures of the three stimuli and asked if they had seen any of them. We found that snakes were detected more often than rabbits or bottles, and that participants showed greater changes in heart rate and greater skin conductance responses in the snake condition than in the other two conditions, even when the participant did not report having seen the snake. A critical component of the SDT is that primates must be able to quickly detect snakes even when their attention is directed elsewhere. Using a novel experimental context-a simulated hike-we assessed arousal and detection without directing participants to attend to any particular stimulus or event. Our data support the SDT by providing evidence of enhanced detection and autonomic arousal even in the absence of detection. Replication of these results using additional controls and experimental contexts will help refine our understanding of snake avoidance by primates.

Impaired Emotional Learning and Involvement of the Corticotropin-Releasing Factor Signaling System in Patients With Irritable Bowel Syndrome

Alterations in central corticotropin-releasing factor signaling pathways have been implicated in the pathophysiology of anxiety disorders and irritable bowel syndrome (IBS). We aimed to characterize the effects of the corticotropin-releasing factor receptor 1 (CRF-R1) antagonist, GW876008, on brain and skin conductance responses during acquisition and extinction of conditioned fear to the threat of abdominal pain in subjects with IBS and healthy individuals (controls). We performed a single-center, randomized, double-blind, 3-period crossover study of 11 women with IBS (35.50 ± 12.48 years old) and 15 healthy women (controls) given a single oral dose (20 mg or 200 mg) of the CRF-R1 antagonist or placebo. Blood-oxygen level-dependent responses were analyzed using functional magnetic resonance imaging in a tertiary care setting. Controls had greater skin conductance responses during acquisition than extinction, validating the fear-conditioning paradigm. In contrast, during extinction, women with IBS had greater skin conductance responses than controls-an effect normalized by administration of a CRF-R1 antagonist. Although the antagonist significantly reduced activity in the thalamus in patients with IBS and controls during acquisition, the drug produced greater suppression of blood-oxygen level-dependent activity in a wide range of brain regions in IBS patients during extinction, including the medial prefrontal cortex, pons, hippocampus, and anterior insula. Although CRF signaling via CRF-R1 is involved in fear acquisition and extinction learning related to expected abdominal pain in patients with IBS and controls, this system appears to be up-regulated in patients with IBS. This up-regulation might contribute to the previously reported abnormal brain responses to expected abdominal pain.

P2-28: An Amplification of Feedback from Facial Muscles Strengthened Sympathetic Activations to Emotional Facial Cues

The facial feedback hypothesis suggests that feedback from cutaneous and muscular afferents influences our emotions during the control of facial expressions. Enhanced facial expressiveness is correlated with an increase in autonomic arousal, and self-reported emotional experience, while limited facial expression attenuates these responses. The present study was aimed at investigating the difference in emotional response in imitated versus observed facial expressions. For this, we measured the facial electromyogram of the corrugator muscle as well as the skin conductance response (SCR) while participants were either imitating or simply observing emotional facial expressions. We found that participants produced significantly greater facial electromyogram activation during imitations compared to observations of angry faces. Similarly, they exhibited significantly greater SCR during imitations to angry faces compared to observations. An amplification of feedback from face muscles during imitation strengthened...

P300 amplitudes in the concealed information test are less affected by depth of processing than electrodermal responses

The Concealed Information Test (CIT) has been used in the laboratory as well as in field applications to detect concealed crime related memories. The presentation of crime relevant details to guilty suspects has been shown to elicit enhanced N200 and P300 amplitudes of the event-related brain potentials (ERPs) as well as greater skin conductance responses (SCRs) as compared to neutral test items. These electrophysiological and electrodermal responses were found to incrementally contribute to the validity of the test, thereby suggesting that these response systems are sensitive to different psychological processes. In the current study, we tested whether depth of processing differentially affects N200, P300, and SCR amplitudes in the CIT. Twenty participants carried out a mock crime and became familiar with central and peripheral crime details. A CIT that was conducted 1 week later revealed that SCR amplitudes were larger for central details although central and peripheral items were remembered equally well in a subsequent explicit memory test. By contrast, P300 amplitudes elicited by crime related details were larger but did not differ significantly between question types. N200 amplitudes did not allow for detecting concealed knowledge in this study. These results indicate that depth of processing might be one factor that differentially affects central and autonomic nervous system responses to concealed information. Such differentiation might be highly relevant for field applications of the CIT.

Is Forgetting of Dreams due to Repression? Experimental Investigations Using Free Associations

This study investigated whether forgetting of dream material is due to repression. Under this assumption, free associations starting from forgotten elements are expected to encounter successively growing resistance. In Experiment 1, 25 participants brought along notes of dreams and were asked to freely associate to five elements from their own dreams and five stimuli from someone else’s dreams. One week later, they were tested for recognition of sequences of their dreams. Afterwards they produced free associations to five elements they had remembered and to five elements not identified (Experiment 2). Skin conductance responses (SCR) and perceived unpleasantness were recorded. Results of Experiment 1 were in line with previous findings from our laboratory: Associations starting from own dream material provoke greater SCRs. Results of Experiment 2 were: In comparison to recognised dream material, unrecognised elements elicited associations accompanied by greater activation. During associations to the latter stimuli, increase of SCR was more frequent, and unpleasant feelings were reported more often. Our findings are in line with Freud’s assumptions on forgetting of dreams.

Limbic Activation and Psychophysiologic Responses to Aversive Visual Stimuli: Interaction with Cognitive Task

We mapped regional brain activity and peripheral psychophysiologic responses, occurring in response to evocative emotional stimuli, and examined whether task instructions could modulate limbic activation. Ten subjects viewed pictures with neutral or aversive emotional content during simultaneous measurement of peripheral psychophysiology and brain activity with [15O]water positron emission tomography (PET). Cognitive task was manipulated by having the subjects rate the pictures or perform a recognition memory task. Aversive pictures, relative to neutral pictures, increased cerebral activity in bilateral amygdala, thalamic/hypothalamic area, midbrain, and left lateral prefrontal cortex, along with greater skin conductance responses (SCR). Voxel-by-voxel correlation coefficients between regional brain activity and SCR showed significant positive correlation peaks in the thalamus and right amygdala. Limbic activation was significantly greater during the rating condition compared to the recognition condition, suggesting that when task demands modify emotional responses, this modulation can occur at the level of limbic activity.

No evidence of classical conditioning of electrodermal responses during anesthesia.

Classical conditioning of skin conductance responses was studied in 26 healthy volunteers and 31 patients who received general anesthesia (0.5 MAC isoflurane-70% nitrous oxide) for minor gynecologic surgery to determine whether there was autonomic evidence of new learning during anesthesia. In the conditioning phase, a loud noise was paired with a target word (conditioned stimulus [CS]). Conditioning was established if the CS produced conditioned responses, i.e., greater skin conductance responses than other, "filler words." In the subsequent elicitation phase, we investigated whether it was possible to elicit similar conditioned responses to the CS when it was presented without noise about 3 h later. Conditioning was established in the control group, who received no anesthesia. There were differences in response magnitudes of 0.32 and 0.27 mu siemen between responses to the CS and filler words, P less than 0.001. In contrast, there was no evidence that conditioning was established during anesthesia. In the elicitation phase, conditioned responses to the CS could be elicited in volunteers; i.e., response magnitudes were greater for the CS than other words (during the first two blocks of trials), with differences of 0.19 to 0.48 mu siemen, P less than 0.05 to P less than 0.001. In contrast, responses to the CS could not be elicited in patients after anesthesia. There was also no evidence of recognition of words that were presented during anesthesia in patients, but recognition was manifested in volunteers. Thus, in contrast to our previous demonstration of conditioning in subjects who received 30% nitrous oxide in oxygen, there was no evidence of conditioning in anesthetized patients.

Interpretation of homophones related to threat in anxiety states.

In previous studies, we have established that anxiety states are characterized by an attentional bias that favors the processing of threatening stimuli. In the present study we extend this finding to ambiguous stimuli, specifically, homophones with spellings that correspond to either a threatening or a neutral meaning. As predicted, clinically anxious subjects used the threatening spellings relatively more than did controls, whereas recovered subjects were intermediate in this respect. Threatening words were associated with greater skin conductance responses than were neutral words, but the groups did not differ in their electrodermal reactions to homophones. We take these findings as evidence that, although the different meanings of ambiguous stimuli may be processed in parallel by all subjects, an interpretive bias operates such that anxiety-prone individuals tend to become preferentially aware of the more threatening meaning of such events.

Cortisol excretion during the defense reaction in humans.

Twelve subjects with specific phobias were exposed to slides with a phobic or a neutral content while cortisol excretion, electrodermal activity, and distress-ratings were studied. Six subjects fearful of blood and mutilation, and six of snakes or spiders, were presented with two sets of ten different slides (phobic or neutral; 8-sec exposures, separated by 50-sec intervals) with the order of presentation balanced between days. Before and after each session, subjects rated feelings of distress, and urine samples were obtained for the determination of cortisol by radioimmunoassay. Electrodermal activity was recorded before and during slide presentation. Compared to neutral exposures, phobic slides elicited larger cortisol excretion, higher distress ratings, and greater skin-conductance responses with slower recovery. No differences between animal and blood and mutilation phobics were observed. Thus, humans having specific phobias exhibit pituitary-adrenal cortical arousal during the defense reaction elicited by slides of their phobic objects.

Habituation and dishabituation of the orienting reaction to between and within trial changes in pitch and loudness.

ABSTRACTWe investigated the effect of between and within trial changes in pitch and loudness on the electrodermal orienting reaction (OR), perceptions of movement, and their interaction. First, following 20 habituation trials (6‐s, 80dB, 1000 Hz), four groups of 10 subjects experienced either an increase or a between‐trial decrease in pitch (2000 or 500 Hz) or loudness (90 or 70 dB) on the 21st trial. Second, four additional groups of 20 subjects heard 20 tones that, within each 6‐s trial, either increased or decreased in pitch (500 to 2000 or 2000 to 500 Hz) or loudness (70 to 90 or 90 to 70 dB). During a dishabituation phase each group was split into halves having a nonchanging tone either increasing or decreasing relative to mean pitch or loudness. After each session subjects rated whether they perceived tones as approaching, retreating, or motionless.Compared with groups experiencing constant stimuli, groups presented tones changing within trials had greater skin conductance responses that habituated slower irrespective of direction of change or its perception. During dishabituation a similar number of subjects dishabituated to a stimulus increase as compared to a decrease irrespective of whether the change was in pitch or loudness. Perceptions of movement treated as an independent variable did not predict habituation or dishabituation of the OR. The results generally support Sokolov, and are discussed in relation to hypotheses presented by Sokolov, O'Gorman, and Bernstein.