Drinking your troubles away: The role of activity in mediating alcohol's reduction of psychological stress.

Two experiments with 133 undergraduates tested the hypothesis that alcohol's reduction of psychological stress depends to an important degree on whether the drinker is also engaged in distracting activity. In Study 1, the factor of whether Ss had received alcohol (1 mg/kg) was crossed, in a 2?×?2 design, with the factor of whether they rated pleasant art slides or did nothing during a period that immediately followed their having received negative feedback on an IQ test (taken earlier). As predicted, a significant interaction effect showed that mood improvement during this recovery period was greatest in the alcohol/slides condition—the only condition in which absolute mood improvement reached significance. Study 2 replicated this effect, ruling out several alternative explanations of the alcohol–activity effect. The implication that alcohol's reduction of psychological stress stems largely from its impairment of cognitive processes that, in conjunction with distracting activity, blocks out stress-inducing thoughts is discussed. (35 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A direct assessment of the role of state and trait negative emotion in aggressive behavior.

Affective priming of aggression was examined in groups low and high in trait negative emotionality (NEM) using a Buss aggression paradigm. Negative affect was induced by exposure to aversive air blasts during some intervals (threat) and not others (safe). Phasic negative affect was assessed using startle reflex potentiation, and tonic distress was indexed by startle sensitization. Participants delivered shocks faster during threat versus safe intervals, indicating that phasic distress primed aggression. Following initial exposure to air blasts, high NEM participants showed enhanced tonic distress and delivered persistently more intense shocks than low NEM participants. These findings indicate that sustained negative affect biases high stress-reactive individuals toward more intense acts of aggression, with phasic distress affecting the rapidity of aggressive response. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Alcohol and human emotion: A multidimensional analysis incorporating startle-probe methodology.

The effect of alcohol intoxication on emotional response was investigated using a model of emotion that includes both arousal and valence dimensions. Thirty-six university students were exposed to multiple presentations of photographic slides selected to elicit distinctive emotional reactions ranging from very pleasant to very unpleasant; half of them received a moderate (approximately .75 ml/kg) dose of ethanol. The students' psychophysiological responses indicated that both general startle reactivity and autonomic indices specific to emotional arousal were diminished by alcohol. However, the affective modulation of startle, occurring with emotional states manipulated by slides with distinct valences, remained intact. These findings suggest that "stress-response dampening" by alcohol may involve a nonspecific attenuation of arousal reactions evident for positive as well as negative stimuli and that theories of motivation for drinking that are based on mood alteration may need refinement. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of experimental context and explicit threat cues on acoustic startle in Vietnam veterans with posttraumatic stress disorder

BACKGROUND: The hypothesis that exaggerated startle in Vietnam veterans with posttraumatic stress disorder (PTSD) reflects an anxiogenic response to stressful contexts was tested. METHODS: Thirty-four nonmedicated Vietnam veterans with PTSD, and 17 combat and 14 civilian non-PTSD controls participated in two testing sessions over separate days. Acoustic startle stimuli were delivered alone or in a test of prepulse inhibition. In the first session, startle was assessed without experimental stress. In the second session, startle was investigated during a stressful "threat of shock" experiment, when subjects anticipated the administration of shocks during threat periods and during safe periods when no shocks were anticipated. RESULTS: The magnitude of startle did not differ significantly among the three groups in the first session, but was increased throughout the threat of shock experiment in the PTSD veterans in the second session. The actual increase in startle in the threat compared to the safe condition did not significantly differ among the three groups. Prepulse inhibition was reduced in the PTSD veterans, compared to the non-PTSD civilians, but not compared to the non-PTSD veterans. CONCLUSION: Exaggerated startle in Vietnam veterans with PTSD reflects an anxiogenic response to an environment that is experienced as stressful.     

Diazepam blocks fear-potentiated startle in humans.

The effects of an anxiolytic drug (diazepam) on emotional responses to aversive stimuli were investigated using physiological measures, including the startle probe reflex. Participants were 54 university students assigned to either a placebo group or a 10 mg or 15 mg diazepam group in a doubleblind design. Blink responses to intermittent noise probes were recorded during viewing of neutral and unpleasant slides. Consistent with prior animal work, diazepam blocked startle potentiation during aversive stimulus processing without decreasing the overall magnitude of startle responses. These findings suggest that a common defensive state mediates startle reflex potentiation in animals and humans and that this index of fear can be used to assess the emotional effects of different drugs. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Cognitive processes and individual differences in judgments relevant to drunk driving.

The present study explored cognitive processes in judgments of drunkenness relative to legally allowable blood alcohol levels for driving. Judgments were based on the manipulation of three cues in hypothetical scenarios in a 3?×?4?×?3 factorial design (Type of Drink?×?Number of Drinks?×?Time to Consume). In addition, personality and behavioral characteristics influencing the accuracy of judgments of drunkenness relative to true blood alcohol levels were examined. Results indicated the presence of several misperceptions and inappropriate response tendencies that potentially can be modified with educational efforts. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Expectancy and pharmacological effects of alcohol on human cognitive and motor performance: The compensation for alcohol effect.

42 male undergraduate social drinkers were led to expect either alcohol or tonic. After actually consuming no alcohol, a low dosage, or a moderate dosage, they performed various cognitive and motor tasks. A questionnaire assessed Ss' responses to the expectancy manipulation and either preceded or followed task administration. A 2?×?3?×?2 MANOVA resulted in a significant Expectancy?×?Dosage interaction for cognitive tasks (letter cancellation, digit span, Raven Progressive Matrices). Ss apparently compensated for alcohol-induced deterioration on these tasks when they were aware they had consumed alcohol. No consistent effects were found for motor tasks (finger tapping, stylus monitoring, standing steadiness, and walking steadiness). (9 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Fear-potentiated startle and electrically evoked startle mediated by synapses in rostrolateral midbrain.

Startle amplitudes are increased when acoustic startle responses are elicited in the presence of a stimulus that has previously been paired with shock. This "fear-potentiated" startle response appears to be mediated via the caudal ventral amygdalofugal pathway to the brainstem. Electrical stimulation of this pathway evokes unconditioned startlelike responses. Collision tests have shown that a monosynaptic connection from amygdala to midbrain mediates these responses. Collision tests here localize these synapses mediating electrically evoked startlelike responses to the rostrolateral midbrain in awake rats. To test whether rostrolateral midbrain synapses also mediate fear-potentiated startle, we lesioned cells in these sites with ibotenic acid. These lesions completely blocked fear potentiation of acoustic startle. These same lesions did not block potentiation of startle by d-amphetamine (6 mg/kg). (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The psychopath as observer: Emotion and attention in picture processing.

This study extended prior work showing abnormal affect–startle modulation in psychopaths. Male prisoners viewed specific categories of pleasant (erotic or thrilling) and unpleasant (victim or direct threat) slide pictures, along with neutral pictures. Acoustic startle probes were presented early (300 and 800 ms) and late (1,800, 3,000, and 4,500 ms) in the viewing interval. At later times, nonpsychopaths showed moderate and strong reflex potentiation for victim and threat scenes, respectively. For psychopaths, startle was inhibited during victim scenes and only weakly potentiated during threat. Psychopaths also showed more reliable blink inhibition across pleasant contents than nonpsychopaths and greater heart rate orienting to affective pictures overall. These results indicate a heightened aversion threshold in psychopaths. In addition, deficient reflex modulation at early times suggested a weakness in initial stimulus evaluation among psychopaths. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Intoxication level and emotional response.

We used affective modulation of the eye-blink component of the startle reflex to examine effects of three levels of alcohol intoxication and a no-intoxication control on emotional responses to pleasant, neutral, and unpleasant pictures. Non-problematic student drinkers (n = 101; 48 female) were randomly assigned to intoxication groups. Normal inhibition of startle during exposure to pleasant pictures was intact across groups. In contrast, potentiation of startle during viewing of unpleasant pictures was evident in the no- and low-intoxication groups, compared to the intermediate- and high-intoxication groups, in which it was significantly reduced. This pattern suggests that a direct and selective anxiolytic effect of alcohol can occur at higher levels of intoxication without an analogous impact on response to emotionally positive stimuli at similar levels. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Affective individual differences and startle reflex modulation.

Potentiation of startle has been demonstrated in experimentally produced aversive emotional states, and clinical reports suggest that potentiated startle may be associated with fear or anxiety. To test the generalizability of startle potentiation across a variety of emotional states as well as its sensitivity to individual differences in fearfulness, the acoustic startle response of 17 high- and 15 low-fear adult Ss was assessed during fear, anger, joy, sadness, pleasant relaxation, and neutral imagery. Startle responses were larger in all aversive affective states than during pleasant imagery. This effect was enhanced among high fear Ss, although follow-up testing indicated that other affective individual differences (depression and anger) may also be related to increased potentiation of startle in negative affect. Startle latency was reduced during high- rather than low-arousal imagery but was unaffected by emotional valence. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

In dubio pro defensio: Initial activation of conditioned fear is not cue specific.

This study explored the time course of conditioned fear response expression. Two neutral male facial expressions served as conditioned stimuli (CS) in a differential trace conditioning that involved either an aversive (n=14) or a nonaversive (n=12) unconditioned stimulus (UCS) in a between-subjects design. Skin conductance response (SCR) to the CSs and startle response magnitudes to acoustic probes presented at early (250 ms) or late (1,750 ms) probe times after CS onset were measured. As expected, conditioned SCR discrimination was observed in both aversive and nonaversive learning, whereas the conditioned potentiation of the startle response was only observed for the aversive UCS condition. Interestingly, conditioned startle discrimination was specific for the later probe time. In contrast, conditioned fear potentiation of the startle response at the early probe time was equally pronounced for CS+ and CS-. These findings suggest that fear-eliciting neural structures are rapidly activated in fear learning, whereas the expression of inhibitory conditioning requires more time, presumably reflecting the involvement of cortical top-down control processes. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Alcohol selectively reduces anxiety but not fear: Startle response during unpredictable versus predictable threat.

Recent theory and empirical research have suggested that fear and anxiety are distinct processes with separable neurobiological substrates. Furthermore, a laboratory procedure has been developed to manipulate fear versus anxiety independently via administration of predictable or unpredictable electric shock, respectively. Benzodiazepines appear to selectively reduce anxiety but not fear in this procedure. The primary aim of this experiment was to determine if alcohol produced a similar selective reduction in anxiety. Intoxicated (target blood alcohol concentration of .08%) and nonintoxicated participants viewed a series of colored squares separated by variable intertrial intervals (ITIs) in 3 conditions. In the predictable shock condition, shocks were administered contingently during every square. In the unpredictable shock condition, shocks were administered noncontingently during both squares and ITIs. In the no-shock condition, no shocks were administered at any time. Alcohol significantly reduced startle potentiation during cues signaling unpredictable but not predictable shock, consistent with the thesis that alcohol selectively reduces anxiety but not fear. In addition, alcohol’s effect on startle potentiation during unpredictable shock was mediated by vigilance. This anxiolytic effect may clarify the nature of alcohol’s reinforcing effects in social and problem drinkers. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The ontogeny of fear-potentiated startle: Effects of earlier-acquired fear memories.

Research has shown that learned fear emerges in a response-specific sequence. For example, freezing is observed at a younger age than is potentiated startle (P. Hunt & B. A. Campbell, 1997). The present study shows that the age at which a specific learned fear response emerges is influenced by the animal's early experiences. Specifically, fear potentiation of startle emerges earlier in development if the rat is given prior fear conditioning to a different stimulus. Some constraints of this "facilitation" effect are determined in follow-up experiments. This facilitation effect may provide a novel way of testing the development of the neural circuits underlying learned fear. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Alcohol and stress response dampening: pharmacological effects, expectancy, and tension reduction

Alcohol consumption and alcohol expectation were separately evaluated in terms of effects on psychophysiological levels prior to stress and reduction of the magnitude of response to stress. 96 male, experienced drinkers were assigned to 8 conditions in a between-Ss design in which beverage consumed (alcohol or tonic), beverage expected (alcohol or tonic), and stressor (self-disclosing speech or threat of shock) were manipulated. Dosage for Ss receiving alcohol was 1 g ethanol/kg. Results indicate strong effects of alcohol consumption on prestress levels, consisting of accelerated heart rate (HR), lower HR variability, higher skin conductance, longer pulse transmission time (PTT), higher "cheerfulness" and lower "anxiety" ratings. Alcohol consumption significantly reduced the magnitude of the HR, PTT, and anxiety responses of Ss to the stressors. No effects attributable to alcohol expectation were found. Results are integrated with the existing literature concerned with pharmacological and cognitive effects of alcohol as they pertain to stress, psychophysiological responses to stress, and tension reduction. (32 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Sex differences in the time course of emotion.

Conventional wisdom holds that women are more "emotional" than men. However, research evidence suggests that sex differences in emotion are considerably more complex. The authors tested hypotheses about sex differences in the engagement of the approach and avoidance motivational systems thought to underpin emotional responses. The authors measured reported emotional experience and startle response magnitude both during the presentation and after the offset of emotional stimuli that engage these motivational systems to assess whether men and women differ in their patterns of immediate response to emotional stimuli and in their patterns of recovery from these responses. Our findings indicated that women were more experientially reactive to negative, but not positive, emotional pictures compared to men, and that women scored higher than men on measure of aversive motivational system sensitivity. Although both men and women exhibited potentiation of the startle response during the presentation of negative pictures relative to neutral pictures, only women continued to show this relative potentiation during the recovery period, indicating that women were continuing to engage the aversive motivational system after the offset of negative emotional pictures. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Age-dependent phenotypic characteristics of a triple transgenic mouse model of Alzheimer disease.

The triple-transgenic mouse line (3×Tg-AD) harboring PS1M146V, APPSwe, and taup301L transgenes represents the only transgenic model for Alzheimer's disease (AD) to date capturing both β-amyloid and tau neuropathology. The present study provides an extensive behavioral characterization of the 3×Tg-AD mouse line, evaluating the emergence of noncognitive and cognitive AD-like symptoms at two ages corresponding to the early (6-7 months) and advanced (12-13 months) stages of AD-pathology. Enhanced responsiveness to aversive stimulation was detected in mutant mice at both ages: the 3×Tg-AD genotype enhanced acoustic startle response and facilitated performance in the cued-version of the water maze. These noncognitive phenotypes were accompanied by hyperactivity and reduced locomotor habituation in the open field at the older age. Signs of cognitive aberrations were also detected at both ages, but they were limited to associative learning. The present study suggests that this popular transgenic mouse model of AD has clear phenotypes beyond the cognitive domain, and their potential relationship to the cognitive phenotypes should be further explored. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Emotion in the criminal psychopath: Startle reflex modulation.

Measured startle-elicited blinks during presentation of affective slides to test hypotheses concerning emotional responding in psychopaths. Ss were 54 incarcerated sexual offenders divided into nonpsychopathic, psychopathic, and mixed groups based on file and interview data. Consistent with findings for normal college students, nonpsychopaths and mixed Ss showed a significant linear relationship between slide valence and startle magnitude, with startle responses largest during unpleasant slides and smallest during pleasant slides. This effect was absent in psychopaths. Group differences in startle modulation were related to affective features of psychopathy, but not to antisocial behavior per se. Psychopathy had no effect on autonomic or self-report responses to slides. These results suggest an abnormality in the processing of emotional stimuli by psychopaths that manifests itself independently of affective report. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Immigration as a multiple-stressor situation: Stress and coping among immigrants from the former Soviet Union in Israel.

The present study investigated the adaptation process of immigrants from the former Soviet Union in Israel as a multiple-stressor situation that involves cognitive appraisals and coping efforts. A sample of 301 new immigrants (residing in Israel three years or less), 67% women, 25 to 45 years old, completed inventories measuring cognitive appraisals of three major immigration stressors--employment, language, and housing difficulties--and the strategies used to cope with these demands. Level of distress (as indicated by depression and anxiety) was also assessed. The results show positive associations between cognitive appraisals of the various stressors, as well as between the coping strategies applied to them, indicating mutual influences between stressors in a multiple-stressor situation. In addition, an interaction between the appraisals of threat/loss of the three stressors predicted the respondents' distress level, supporting the potentiation model of coping with multiple stressors. Last, the findings support the notion of a stable coping style by showing especially high correlations between coping efforts with different stressors. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The startle probe response: A new measure of emotion?

Twenty undergraduate subjects were presented with unsignaled 50-ms white noise bursts (95 dB) to probe their perceptual processing while viewing 36 colored photographic slides, depicting pleasant/interesting, neutral/dull, or unpleasant/interesting scenes and objects. Startle magnitudes to the noise bursts as measured by the eyeblink response were largest for unpleasant material and smallest for positive material. This effect was independent of measures or orienting, arousal, and interest in the materials. The results reconcile conflicting animal and human research. Alternative attentional and response matching explanations of these startle probe effects were evaluated. The startle probe is proposed as a broadly useful tool for studying emotion, its development and modification, and for the assessment of pathological anxiety. (PsycINFO Database Record (c) 2010 APA, all rights reserved)