The time course of emotional and attentional modulation of the startle eyeblink reflex during imagery.

Two studies were conducted to examine the time course of attentional and emotional processing using the startle eyeblink reflex. Forty-eight participants listened to a series of 1500-ms tones that occurred every 6 s. The tones signaled participants to generate emotional images that were positive or negative in valence and high or low in arousal. Auditory startle probes occurred 120 ms, 1400 ms, or 4000 ms after tone onset. Startle inhibition was seen 120 ms after tone onset and startle facilitation was found at 1400 ms, compared to startles elicited 4000 ms after tone onset. Startle inhibition was greater at 120 ms when the tone signaled imagery, indicating an attentional effect. A second experiment found that this effect was not caused by the comparative rarity of the tones signaling imagery. Startle magnitude was also smaller at 1400 ms when the tone signaled imagery compared to no-imagery tones. The type of imagery did not modulate the startle response 120 ms after tone onset, but negative valence imagery enhanced startle magnitude at 1400 ms and 4000 ms after tone onset, and high arousal also enhanced startle magnitude at 4000 ms. Thus, attention and emotion followed different time courses in affecting the startle reflex response during imagery.

The impact of imagining completed versus interrupted smoking on cigarette craving.

A brief imagery procedure was used to determine the effects of imagining completed versus interrupted smoking on self-reported craving, mood, autonomic functioning, and reaction time to an auditory probe. Cigarette smokers (N = 60) imagined actively participating in 3 types of scenarios in which they (a) engaged in smoking behavior, (b) attempted to smoke but were interrupted by a lack of cigarettes, and (c) were not confronted with smoking cues. Imagining both completed and interrupted smoking produced equivalent increases in craving compared with imagining neutral scenarios. Imagery of interrupted smoking was associated with higher heart rate and increased negative mood relative to the other scenario types, whereas imagery of completed smoking was associated with slower reaction time on the probe reaction-time task. Theoretical and methodological implications of the results are discussed.

Emotional imagery, the visual startle, and covariation bias: an affective matching account.

This study assessed the effects of imagery valence and arousal on the visually prompted startle reflex, heart rate, and estimates of probe occurrence in 24 males and 22 females. Valence and arousal independently augmented startle magnitudes, similar to prior research with acoustic probes (Witvliet, C.V.O., Vrana, S.R., 1995. Psychophysiological responses as indices of affective dimensions, Psychophysiology 32, 436-443). In both of these studies, arousal exerted stronger effects than valence on the startle reflex. Arousal also facilitated heart rate acceleration. Participants' estimates of startle flash occurrence reflected a covariation bias. Estimates were higher and more accurate for the high-arousal conditions and for the negative conditions, paralleling startle magnitude findings. Results suggest that affective response matching processes (rather than affective stimulus matching) influenced both startle reflex magnitudes and probe frequency estimates. Comparisons with the covariation bias literature are drawn, differences are addressed, and directions for future research are suggested.

Effect of worrisome and relaxing thinking on fearful emotional processing.

This study replicated and extended previous data suggesting that worry inhibits emotional processing of fearful imagery. Female participants categorized as either victimization-fearful (N = 24) or victimization and speech-fearful (N = 27) completed trials of worrisome or relaxing thinking and tone-cued imagery. For each trial, participants engaged in 30 s of relaxing or worrisome (speech or victimization) thinking and then imagined speech or victimization fear scenes for 15 s. Heart rate and facial electromyography activity at the corrugator supercilii region were measured during the think and imagery periods to estimate degree of emotional processing of the fear imagery. Consistent with earlier findings, there was greater heart rate suppression during fearful imagery after a period of worry as opposed to relaxation. This finding, however, may have been the result of physiological differences between worrisome and relaxation thinking. Corrugator activation during thinking showed a similar pattern as the heart rate data while corrugator activation during fearful imagery was dependent on the baseline employed. These data, in combination with the imagery ratings data, suggest that worry may be an unsuccessful strategy for avoiding the physiological activation associated with emotional processing.

Physiological response to a minimal social encounter: effects of gender, ethnicity, and social context.

This study examined physiological response to an encounter with and touch by an unfamiliar person. Fifty-five African American (23 male, 30 female) and 51 European American (23 male, 28 female) undergraduates participated. A Black or White interactor entered the room, introduced himself or herself, checked equipment for 30 s, and then took a pulse for 30 s. Entry of the interactor resulted in increased corrugator and zygomaticus facial muscle activity (EMG), increased skin conductance (SC), and heart rate (HR) acceleration. Corrugator EMG was greater among Black subjects; White subjects responded with more zygomatic EMG and SC and greater HR acceleration. Women showed a more positive facial expression than did men. Being touched reduced EMG and HR but resulted in increased SC. White and Black males showed more HR acceleration when encountering a Black male interactor.

Effect of self-focused attention on the startle reflex, heart rate, and memory performance among socially anxious and nonanxious individuals.

The present study examined the effect of self-focused attention on the startle reflex and heart rate and assessed the assumption that socially anxious individuals become self-focused in evaluative situations. Twenty-five high and 30 low socially anxious men performed a digit recall task under evaluative or nonevaluative instructions. Half of the trials were performed under self-focused conditions and half under non-self-focused conditions. Self-focus led to larger startle responses among socially anxious individuals and had no effect on heart rate. Self-focus combined with evaluation led to poorer recall performance among all subjects. Results provide evidence against a directional change in attention during self-focused attention and favor the view that self-focus increases access to self-relevant thought content and decreases available processing resources.

Some touching situations: the relationship between gender and contextual variables in cardiovascular responses to human touch.

This study examined how cardiovascular reactivity to human touch is affected by the social context of the situation. Context for a ten-second touch was manipulated for 61 male and 64 female undergraduate participants in three ways: professional touch, were participants were touched on the wrist to have their pulse taken; social touch, an unexplained touch to the same area of the arm; and a no-touch control, where participants were told their pulse was being taken automatically without being touched. Social context was also manipulated by employing both same-sex and opposite-sex touch experimenters. In the professional touch and no-touch conditions, participants' heart rate and blood pressure decreased overall; however, in the social touch condition initial increases were observed for both measures. Female experimenters produced greater heart rate decreases than male experimenters. The greatest cardiovascular increases were found with women being touched by men in the social condition. These data suggest that both context and gender are important contextual factors in determining cardiovascular reactivity.

Smoking withdrawal symptoms in response to a trauma-related stressor among Vietnam combat veterans with posttraumatic stress disorder.

This study investigated the relationship between a trauma-related stressor and smoking withdrawal symptoms in 25 male Vietnam combat veterans with posttraumatic stress disorder (PTSD) using a within-subjects design. All subjects were smokers. The stressor involved a modified Stroop task, in which the veterans color-named either anxiety-related or neutral control words. Anxiety-related words produced more withdrawal symptoms than neutral control words, including increased craving, negative affect symptoms, somatic symptoms, and lack of alertness.

Psychophysiological responses as indices of affective dimensions.

The startle reflex, facial electromyogram (EMG), and autonomic nervous system responses were examined during imagery varying in affective valence and arousal. Subjects (N = 48) imagined affective situations during tone-cued 8-s trials. Startle blink magnitudes were larger and latencies faster during negatively valent than during positively valent conditions and during high-arousal than during low-arousal conditions. Greatest heart rate acceleration and fastest and largest skin conductance responses to startle probes occurred during high-arousal imagery. Zygomatic and orbicularis oculi facial muscle activities were higher during high-arousal imagery, whereas corrugator muscle activity was higher during low-arousal imagery. Zygomatic and corrugator activity also varied with emotional valence. The startle and facial EMG responses are most parsimoniously organized by the negative affect (NA) and positive affect (PA) dimensions, respectively. This NA/PA framework integrates previous research, dimensional theories of emotional behavior, and physiological assessment of pathological emotion.

Emotional modulation of skin conductance and eyeblink responses to startle probe.

In this study, I examined emotional modulation of the eyeblink, skin conductance, and cardiac responses to an acoustic startle (103 dB[A] white noise) probe. Twenty-five female and 17 male undergraduates imagined pleasant, neutral, and fearful situations in a tone-cured imagery procedure. Both the eyeblink and skin conductance responses to startle probes were potentiated (larger magnitude, shorter latency) during fear as compared with neutral and pleasant imagery. The amount of emotional modulation in these two response systems was significantly correlated both between and within subjects. The startle probe interrupted ongoing cardiac deceleration during the imagery task, but but this interruption was not related to the emotional content of imagery.

Emotional imagery in simple and social phobia: fear versus anxiety.

In a first study, phobic volunteer subjects (N = 60) reacted psychophysiologically with greater vigor to imagery of their own phobic content than to other fearful or nonaffective images. Imagery heart rate responses were largest in subjects with multiple phobias. For simple (dental) phobics, cardiac reactivity was positively correlated with reports of imagery vividness and concordant with reports of affective distress; these relationships were not observed for social (speech) phobics. In a second study, these phobic volunteers were shown to be similar on most measures to an outpatient clinically phobic sample. In an analysis of the combined samples, fearful and socially anxious subtypes were defined by questionnaires. Only the fearful subtype showed a significant covariation among physiological responses, imagery vividness, and severity of phobic disorder. This fearful-anxious distinction seems to cut across diagnostic categories, providing a heuristic perspective from which to view anxiety disorders.

The psychophysiology of disgust: differentiating negative emotional contexts with facial EMG.

The goals of this study were (a) to examine differing views on the relationship between self-report of emotion and physiological expression of emotion, (b) to differentiate between negative emotional contexts during imagery using facial electromyogram (EMG), and (c) to describe the facial muscle patterning and autonomic physiology of situations that involve expelling or avoiding disgusting sensory stimulation. Fifty subjects imagined situations eliciting disgust, anger, pleasure, and joy in 8-s trials using a tone-cued imagery procedure. Heart rate, skin conductance level, and facial EMG at the corrugator, zygomatic, and levator labii superioris/alesque muscle regions were recorded during imagery, and self-reports of emotion were collected after imagery trials. Self-reports of emotion produced results consistent with the affective categorization of the images. Activity at the levator labii region was higher during disgust than during anger imagery. Corrugator region increase characterized the negative as compared with the positive emotional contents, and activity at the zygomatic region was higher during joy imagery than during the other three emotions. Heart rate acceleration was greater during disgust, anger, and joy imagery than during pleasant imagery. Disgust imagery could be discriminated from anger imagery using facial EMG, and the expressive physiology of disgust was occasioned by the action set of active avoidance or rejection of sensory stimulation.

Emotional processing and fear measurement synchrony as indicators of treatment outcome in fear of flying.

Minimal-therapist-involvement stress inoculation training was used to treat flying phobics. Relative to no-treatment controls, treatment subjects reported more fear reduction, were more likely to participate in an exposure session, and flew more during a two-month follow-up period. Subjects who exhibited synchronous changes in heart rate and report of anxiety during exposure had greater fear reduction than subjects showing less synchrony. Subjects who voluntarily took plane flights in the two months following treatment showed greater indications of emotional processing during in vivo exposure. Relative to flight avoiders, fliers had higher mean heart rate in the plane, a greater reduction in heart rate from the beginning to the end of the flight, and greater reported fear reduction from pre- to post-flight.

Fear imagery and the startle-probe reflex.

Blink reflexes to acoustic probes, heart rate, and subjective reports were studied during affective memory imagery. Thirty-six undergraduates memorized 6 pairs of neutral and fearful sentences. After learning each pair, they relaxed and listened to a series of uniform tones, one every 6 s. A change in tone pitch (higher or lower) cued recall of one of the two sentences. At the first cue tone, groups (n = 12) were under different instructions: (a) ignore the sentence and relax, (b) silently articulate the sentence, and (c) imagine the sentence content as a personal experience. At the second cue tone, all subjects performed the imagery task. Startle probes (50-ms, 95-dB white noise) were presented unpredictably during relaxation and recall trials. Probe blink reflexes were larger and cardiac rate faster at fear sentence recall than at neutral sentence recall or relaxation. For probe reflexes, this effect was greater for imagery than for nonsemantic recall tasks.