The heart beats to reward: the effect of monetary incentive on heart rate

Arousal, Gray's theory of anxiety, and the etiology of psychopathy

This paper focuses on Jeffrey Gray's theory of anxiety from the perspective of Fowles' (1980) application of his work to theories of arousal, psychophysiology, and the etiology of psychopathy. Although highly influential, the concept of general arousal failed to find support in terms of between-individuals assessment with multiple physiological measures. Gray's constructs of a behavioral inhibition system (BIS) that mediates anxiety, a behavioral approach or activation system (BAS) that energizes behavior to approach rewards, and a nonspecific arousal system that energizes behavior captured aspects of arousal. Fowles (1980) proposed that the BIS elicits electrodermal activity in response to threats, the BAS increases heart rate in response to reward incentive cues, and psychopathy is associated with a weak BIS. The paper reviews Gray's impact on future research on these topics, including early proposals relevant to the National Institute of Mental Health's Research Domain Criteria. Finally, the paper summarizes the evolution of theories of the etiology of psychopathy since 1980, noting ways in which aspects of Gray's theory are still seen in psychopathy research. Patrick's triarchic model has emerged as a major theory of psychopathy. Beauchaine's trait impulsivity theory of Attention Deficit Hyperactivity Disorder also is relevant.

How is variability in physiological responses to social stress related to punishment and reward sensitivities? Preliminary findings from the revised reinforcement sensitivity theory of personality perspective

OBJECTIVE

Although personality traits are assumed to have biological/physiological foundations, research has yielded mixed evidence regarding the relationship between personality and physiological stress responses. Moreover, the field has often overlooked the contemporary neuroscience-based personality approach, known as the Reinforcement Sensitivity Theory (RST) of Personality, in stress research.

METHOD

The present study examined the relationship between the revised RST's personality dimensions and heart rate and skin conductance level (SCL) in response to the Trier Social Stress Test in a sample of 61 healthy university students.

RESULTS

Piecewise latent growth curve analysis controlling for the participants' current life stress, smoking use, and caffeine intake revealed that individuals with higher behavioral inhibition exhibited higher physiological reactivity, whereas those with high reward sensitivity showed smaller heart rate reactivity. The behavioral disengagement facet of the behavioral inhibition scale was associated with reduced sympathetic arousal during the stress task. Additionally, reward interest was associated with a larger recovery of SCL.

CONCLUSION

Results were generally in line with the revised theory. The study findings were discussed within the paradigm of the approach-avoidance conflict and highlighted the importance of reward sensitivity in stress resilience.

Prefrontal tDCS attenuates counterfactual thinking in female individuals prone to self-critical rumination

The tendency to ruminate (i.e., repetitive negative self-referential thoughts that perpetuate depressive mood) is associated with (a) an elevated propensity to maladaptively experience counterfactual thinking (CFT) and regret, and (b) hypo-activity of the left dorsolateral prefrontal cortex (DLPFC). The goal of this study was to investigate whether anodal transcranial direct current stimulation (tDCS) over the left DLPFC, in function of self-critical rumination tendencies, momentarily reduces counterfactual thinking and regret (assessed via self-report and psychophysiological indices). Eighty healthy participants with different levels of self-critical rumination received either anodal or sham tDCS while performing a decision making task in which they were repeatedly confronted with optimal, suboptimal, and non-optimal choice outcomes. The results showed that among rumination-prone individuals, anodal (versus sham) tDCS was associated with decreased CFT and attenuated psychophysiological reactivity to the differential choice outcomes. Conversely, among low rumination-prone individuals, anodal (versus sham) tDCS was associated with increased CFT and regret, but in absence of any effects on psychophysiological reactivity. Potential working mechanisms for these differential tDCS effects are discussed. Taken together, these results provide initial converging evidence for the adaptive effects of left prefrontal tDCS on CFT and regret to personal choice outcomes among individuals prone to engage in self-critical rumination.

Development of a Classical Conditioning Task for Humans Examining Phasic Heart Rate Responses to Signaled Appetitive Stimuli: A Pilot Study

Cardiac responses to appetitive stimuli have been studied as indices of motivational states and attentional processes, the former being associated with cardiac acceleration and latter deceleration. Very few studies have examined heart rate changes in appetitive classical conditioning in humans. The current study describes the development and pilot testing of a classical conditioning task to assess cardiac responses to appetitive stimuli and cues that reliably precede them. Data from 18 adults were examined. They were shown initially neutral visual stimuli (putative CS) on a computer screen followed by pictures of high-caloric food (US). Phasic cardiac deceleration to food images was observed, consistent with an orienting response to motivationally significant stimuli. Similar responses were observed to non-appetitive stimuli when they were preceded by the cue associated with the food images, suggesting that attentional processes were engaged by conditioned stimuli. These autonomic changes provide significant information about classical conditioning effects in humans.

Energy investment and motivation: The additive impact of task demand and reward value on exerted force in hand grip tasks

According to motivational intensity theory, individuals are motivated to conserve energy when pursuing goals. They should invest only the energy required for success and disengage if success is not important enough to justify the required energy. We tested this hypothesis in five experiments assessing exerted muscle force in isometric hand grip tasks as indicator of energy investment. Our results provided mixed evidence for motivational intensity theory. Corroborating its predictions, energy investment was a function of task demand. However, we did not find evidence for the predicted disengagement, and we observed that participants exerted in most conditions more force than required. Furthermore, the data could be better explained by a model that predicted an additive effect of task demand and success importance than by models drawing on motivational intensity theory’s predictions. These results illustrate the strong link between energy investment and task demand but challenge motivational intensity theory’s primacy of energy conservation.

Task-related activity in human visual cortex

The brain exhibits widespread endogenous responses in the absence of visual stimuli, even at the earliest stages of visual cortical processing. Such responses have been studied in monkeys using optical imaging with a limited field of view over visual cortex. Here, we used functional MRI (fMRI) in human participants to study the link between arousal and endogenous responses in visual cortex. The response that we observed was tightly entrained to task timing, was spatially extensive, and was independent of visual stimulation. We found that this response follows dynamics similar to that of pupil size and heart rate, suggesting that task-related activity is related to arousal. Finally, we found that higher reward increased response amplitude while decreasing its trial-to-trial variability (i.e., the noise). Computational simulations suggest that increased temporal precision underlies both of these observations. Our findings are consistent with optical imaging studies in monkeys and support the notion that arousal increases precision of neural activity.

The brain exhibits widespread endogenous responses in the absence of visual stimuli, even at the earliest stages of visual cortical processing. This fMRI study characterizes a widespread hemodynamic response in early visual cortex that is not related to visual input but instead reflects a participant’s engagement in a task, is modulated by expected monetary reward, and may reflect neural quenching.

Is satisficing really satisfying? Satisficers exhibit greater threat than maximizers during choice overload

When selecting from too many options (i.e., choice overload), maximizers (people who search exhaustively to make decisions that are optimal) report more negative post-decisional evaluations of their choices than do satisficers (people who search minimally to make decisions that are sufficient). Although ample evidence exists for differences in responses after-the-fact, little is known about possible divergences in maximizers' and satisficers' experiences during choice overload. Thus, using the biopsychosocial model of challenge/threat, we examined 128 participants' cardiovascular responses as they actively made a selection from many options. Specifically, we focused on cardiovascular responses assessing the degree to which individuals (a) viewed their decisions as valuable/important and (b) viewed themselves as capable (vs. incapable) of making a good choice. Although we found no differences in terms of the value individuals placed on their decisions (i.e., cardiovascular responses of task engagement), satisficers-compared to maximizers-exhibited cardiovascular responses consistent with feeling less capable of making their choice (i.e., greater relative threat). The current work provides a novel investigation of the nature of differences in maximizers'/satisficers' momentary choice overload experiences, suggesting insight into why they engage in such distinct search behaviors.

Poor control of interference from negative content hampers the effectiveness of humour as a source of positive emotional experiences

The brain-based ability to direct attention away from interfering negative information may co-determine to which degree one may benefit from humour as a source of positive emotional experiences. This should be particularly relevant when it comes to humour that implicates a target the joke makes fun of, which inherently entails rivalry between positive and negative emotional representations. One hundred healthy individuals completed a pictorial negative affective priming task and a nonverbal humour processing task. In line with the notion that during the elaborative processing of malicious jokes, interference from negative emotional representations hampers the experience of amusement, participants took more time to judge their amusement evoked by malicious compared to benign jokes. Lesser ability to distract attention from interfering negative emotional representations was associated with slower judgements of amusement following the processing of malicious jokes, as well as with lower amusement ratings. The time it took participants to comprehend the punch-lines was not affected, neither was the immediate, short-lived pleasure after having comprehended the humour, measured by characteristic transient cardiac activation. The findings suggest that the effective use of humour as a source of positive emotional experiences requires the ability to overcome the dark side of typical humour.

Motivated Cognition: Effects of Reward, Emotion, and Other Motivational Factors Across a Variety of Cognitive Domains

A growing body of literature has demonstrated that motivation influences cognitive processing. The breadth of these effects is extensive and span influences of reward, emotion, and other motivational processes across all cognitive domains. As examples, this scope includes studies of emotional memory, value-based attentional capture, emotion effects on semantic processing, reward-related biases in decision making, and the role of approach/avoidance motivation on cognitive scope. Additionally, other less common forms of motivation–cognition interactions, such as self-referential and motoric processing can also be considered instances of motivated cognition. Here I outline some of the evidence indicating the generality and pervasiveness of these motivation influences on cognition, and introduce the associated ‘research nexus’ at Collabra: Psychology.

Autonomic reactivity and vulnerability to depression: A multi-wave study

The ability of the autonomic nervous system to flexibly adapt to environmental changes is thought to indicate efficient use of self-regulatory resources. Deficits in autonomic reactivity appear to characterize current depression; however, whether autonomic reactivity confers vulnerability to future depression when individuals encounter environmental stressors is unknown. Fluctuations in respiratory sinus arrhythmia (RSA) and heart rate (HR) were evaluated in response to emotion-eliciting films among 134 undergraduates. Negative events and depressive symptoms were assessed 5 times across 12 weeks. Multilevel modeling demonstrated that smaller decreases in RSA in response to sadness, greater increases in HR following sadness, and smaller increases in HR to amusement were prospectively associated with greater depressive symptoms when individuals encountered high levels of idiographically assessed negative events. These results demonstrate that the lack of contextually appropriate autonomic reactivity may confer vulnerability to depression under conditions of environmental stress, perhaps due to attenuated capacity for effective self-regulation. (PsycINFO Database Record

Patterns of brain and cardiovascular activation while solving rule-discovery and rule-application numeric tasks

It is known that solving mental tasks leads to tonic increase in cardiovascular activity. Our previous research showed that tasks involving rule application (RA) caused greater tonic increase in cardiovascular activity than tasks requiring rule discovery (RD). However, it is not clear what brain mechanisms are responsible for this difference. The aim of two experimental studies was to compare the patterns of brain and cardiovascular activity while both RD and the RA numeric tasks were being solved. The fMRI study revealed greater brain activation while solving RD tasks than while solving RA tasks. In particular, RD tasks evoked greater activation of the left inferior frontal gyrus and selected areas in the parietal, and temporal cortices, including the precuneus, supramarginal gyrus, angular gyrus, inferior parietal lobule, and the superior temporal gyrus, and the cingulate cortex. In addition, RA tasks caused larger increases in HR than RD tasks. The second study, carried out in a cardiovascular laboratory, showed greater increases in heart rate (HR), systolic blood pressure (SBP), diastolic blood pressure (DBP), and mean arterial pressure (MAP) while solving RA tasks than while solving RD tasks. The results support the hypothesis that RD and RA tasks involve different modes of information processing, but the neuronal mechanism responsible for the observed greater cardiovascular response to RA tasks than to RD tasks is not completely clear.

Treatment for Anhedonia: A Neuroscience Driven Approach

Anhedonia, or loss of interest or pleasure in usual activities, is characteristic of depression, some types of anxiety, as well as substance abuse and schizophrenia. Anhedonia is a predictor of poor long-term outcomes, including suicide, and poor treatment response. Because extant psychological and pharmacological treatments are relatively ineffective for anhedonia, there is an unmet therapeutic need for this high-risk symptom. Current psychological and drug treatments for anxiety and depression focus largely on reducing excesses in negative affect rather than improving deficits in positive affect. Recent advances in affective neuroscience posit that anhedonia is associated with deficits in the appetitive reward system, specifically the anticipation, consumption, and learning of reward. In this paper, we review the evidence for positive affect as a symptom cluster, and its neural underpinnings, and introduce a novel psychological treatment for anxiety and depression that targets appetitive responding. First, we review anhedonia in relation to positive and negative valence systems and current treatment approaches. Second, we discuss the evidence linking anhedonia to biological, experiential, and behavioral deficits in the reward subsystems. Third, we describe the therapeutic approach for Positive Affect Treatment (PAT), an intervention designed to specifically target deficits in reward sensitivity.

Oral sucrose for heel lance enhances adenosine triphosphate use in preterm neonates with respiratory distress

Objective:

To examine the effects of oral sucrose on procedural pain, and on biochemical markers of adenosine triphosphate utilization and oxidative stress in preterm neonates with mild to moderate respiratory distress.

Study design:

Preterm neonates with a clinically required heel lance that met study criteria (n = 49) were randomized into three groups: (1) control (n = 24), (2) heel lance treated with placebo and non-nutritive sucking (n = 15) and (3) heel lance treated with sucrose and non-nutritive sucking (n = 10). Plasma markers of adenosine triphosphate degradation (hypoxanthine, xanthine and uric acid) and oxidative stress (allantoin) were measured before and after the heel lance. Pain was measured using the Premature Infant Pain Profile. Data were analyzed using repeated measures analysis of variance, chi-square and one-way analysis of variance.

Results:

We found that in preterm neonates who were intubated and/or were receiving ⩾30% FiO₂, a single dose of oral sucrose given before a heel lance significantly increased markers of adenosine triphosphate use.

Conclusion:

We found that oral sucrose enhanced adenosine triphosphate use in neonates who were intubated and/or were receiving ⩾30% FiO₂. Although oral sucrose decreased pain scores, our data suggest that it also increased energy use as evidenced by increased plasma markers of adenosine triphosphate utilization. These effects of sucrose, specifically the fructose component, on adenosine triphosphate metabolism warrant further investigation.

Psychophysiological Responses During the Anticipation of Emotional Pictures

The present study sought to investigate peripheral physiological responses to the anticipation of explicitly and ambiguously cued emotional pictures. Emotionally positive and negative as well as neutral pictures were presented to 32 healthy subjects. At the beginning of an anticipation period they were cued about the valence of the upcoming picture (neutral, positive, negative, or ambiguous). Skin conductance, heart rate, and zygomaticus and corrugator electromyogram responses were measured during anticipation and perception. Responses specific to the emotional conditions were observed during anticipation as well as during perception. During the anticipation of ambiguously cued pictures, responses were similar to responses elicited by anticipating negative pictures. In line with results from brain imaging studies, peripheral physiological responses could be interpreted to reflect a negative bias for ambiguous events.

Evidence for effects of task difficulty but not learning on neurophysiological variables associated with effort

Learning to master a task is expected to be accompanied by a decrease in effort during task execution. We examine the possibility to monitor learning using physiological measures that have been reported to reflect effort or workload. Thirty-five participants performed different difficulty levels of the n-back task while a range of physiological and performance measurements were recorded. In order to dissociate non-specific time-related effects from effects of learning, we used the easiest level as a baseline condition. This condition is expected to only reflect non-specific effects of time. Performance and subjective measures confirmed more learning for the difficult level than for the easy level. The difficulty levels affected physiological variables in the way as expected, therewith showing their sensitivity. However, while most of the physiological variables were also affected by time, time-related effects were generally the same for the easy and the difficult level. Thus, in a well-controlled experiment that enabled the dissociation of general time effects from learning we did not find physiological variables to indicate decreasing effort associated with learning. Theoretical and practical implications are discussed.

Frontal brain asymmetry and transient cardiovascular responses to the perception of humor

The study examined the relationship of individual differences in prefrontal brain asymmetry, measured by the EEG in resting conditions, to the individual's responsivity in the context of humor (n=42). Several weeks after the EEG recording, immediate cardiovascular responses to the perception of humor and behavioral indicators of humor processing were obtained in an experimental paradigm involving non-verbal cartoons. Relatively greater resting activity in the left than right prefrontal cortex, particularly at the ventrolateral positions, was associated with faster detection of humor, a more pronounced cardiac response to the perception of humor (heart rate and cardiac output), and more accessible internal positive affective states (indicated by faster reports of amusement levels). The study confirms and extends findings of the relevance of prefrontal brain asymmetry to affective responsivity, contributing evidence in the domain of positive affect and humor, and demonstrating relationships to the immediate cardiovascular response pattern to an emotional event.

Goal relevance and goal conduciveness appraisals lead to differential autonomic reactivity in emotional responding to performance feedback

Using an appraisal framework, the present experiment tested the hypothesis that goal relevance and goal conduciveness have an interactive effect on emotional responding. We expected that elicitation of positive or negative emotions in response to events that are conducive or obstructive to attainment of one's goals depends on the level of goal relevance. To test this hypothesis, we presented 119 participants with positive (success) or negative (failure) performance feedback of high or low relevance in an achievement context. Feeling self-report showed effects of conduciveness, but no interaction with relevance. Physiological reactivity showed the predicted interaction effect on cardiac autonomic regulation (CAR), with higher CAR for high-relevance conducive than obstructive conditions. Moreover, mean arterial pressure (MAP) and skin conductance level (SCL) differed between conducive and obstructive conditions, and heart rate (HR) and SCL differed between relevance conditions. Implications for the plausibility and current empirical support of the interaction hypothesis are discussed.

Acute tryptophan depletion attenuates brain-heart coupling following external feedback

External and internal performance feedback triggers neural and visceral modulations such as reactions in the medial prefrontal cortex and insulae or changes of heart period (HP). The functional coupling of neural and cardiac responses following feedback (cortico-cardiac connectivity) is not well understood. While linear time-lagged within-subjects correlations of single-trial EEG and HP (cardio-electroencephalographic covariance tracing, CECT) indicate a robust negative coupling of EEG magnitude 300 ms after presentation of an external feedback stimulus with subsequent alterations of heart period (the so-called N300H phenomenon), the neurotransmitter systems underlying feedback-evoked cortico-cardiac connectivity are largely unknown. Because it has been shown that acute tryptophan depletion (ATD), attenuating brain serotonin (5-HT), decreases cardiac but not neural correlates of feedback processing, we hypothesized that 5-HT may be involved in feedback-evoked cortico-cardiac connectivity. In a placebo-controlled double-blind cross-over design, 12 healthy male participants received a tryptophan-free amino-acid drink at one session (TRP−) and a balanced amino-acid control-drink (TRP+) on another and twice performed a time-estimation task with feedback presented after each trial. N300H magnitude and plasma tryptophan levels were assessed. Results indicated a robust N300H after TRP+, which was significantly attenuated following TRP−. Moreover, plasma tryptophan levels during TRP+ were correlated with N300H amplitude such that individuals with lower tryptophan levels showed reduced N300H. Together, these findings indicate that 5-HT is important for feedback-induced covariation of cortical and cardiac activity. Because individual differences in anxiety have previously been linked to 5-HT, cortico-cardiac coupling and feedback processing, the present findings may be particularly relevant for futures studies on the relationship between 5-HT and anxiety.

Heart rate responses to parental behavior in depressed adolescents

In order to more fully understand the abnormalities in emotional responding associated with adolescent depression we examined clinically depressed and non-depressed adolescents' physiological responses to their parents' negative emotional behavior, as indexed by their heart rate responses to parental angry and dysphoric behavior during laboratory-based interactions. Maternal angry and dysphoric behavior predicted heart rate deceleration amongst non-depressed adolescents, a response that was not observed in depressed adolescents. Fathers' angry behavior predicted significant heart rate acceleration in depressed (but not non-depressed) adolescents, whereas fathers' dysphoric behavior predicted heart rate deceleration amongst depressed but not amongst non-depressed adolescents. These findings are interpreted within the framework of orienting and defense cardiac responses, and suggest that reactivity in adolescent depression is characterized by the absence of a normative orienting response toward aversive maternal behaviors, and a defensive physiological response to aggressive paternal behavior.

Human and laboratory rodent low response to alcohol: is better consilience possible?

If people are brought into the laboratory and given alcohol, there are pronounced differences among individuals in many responses to the drug. Some participants in alcohol challenge protocols show a cluster of 'low level of responses to alcohol' determined by observing post-drinking-related changes in subjective, motor and physiological effects at a given dose level. Those individuals characterized as having low level of response (LR) to alcohol have been shown to be at increased risk for a lifetime diagnosis of alcohol dependence (AD), and this relationship between low LR and AD appears to be in part genetic. LR to alcohol is an area where achieving greater consilience between the human and the rodent phenotypes would seem to be highly likely. However, despite extensive data from both human and rodent studies, few attempts have been made to evaluate the human and animal data systematically in order to understand which aspects of LR appear to be most directly comparable across species and thus the most promising for further study. We review four general aspects of LR that could be compared between humans and laboratory animals: (1) behavioral measures of subjective intoxication; (2) body sway; (3) endocrine responses; and (4) stimulant, autonomic and electrophysiological responses. None of these aspects of LR provide completely face-valid direct comparisons across species. Nevertheless, one of the most replicated findings in humans is the low subjective response, but, as it may reflect either aversively valenced and/or positively valenced responses to alcohol as usually assessed, it is unclear which rodent responses are analogous. Stimulated heart rate appears to be consistent in animal and human studies, although at-risk subjects appear to be more rather than less sensitive to alcohol using this measure. The hormone and electrophysiological data offer strong possibilities of understanding the neurobiological mechanisms, but the rodent data in particular are rather sparse and unsystematic. Therefore, we suggest that more effort is still needed to collect data using refined measures designed to be more directly comparable in humans and animals. Additionally, the genetically mediated mechanisms underlying this endophenotype need to be characterized further across species.

The heart contracts to reward: monetary incentives and preejection period

Wright's (1996) integration of motivational intensity theory (Brehm & Self, 1989) and Obrist's (1981) active coping approach predict that cardiovascular reactivity in active coping depends on the importance of success when task difficulty is unclear. Despite the support for this perspective, one of the basic hypotheses-the mediation of these effects by beta-adrenergic activity-has not been tested yet. To close this gap, participants worked on a delayed-matching-to-sample task and could earn either 1, 15, or 30 Swiss Francs for a successful performance. Results showed that preejection period reactivity-an indicator of beta-adrenergic impact on the heart-increased with increasing incentive value. Thus, this experiment closes a gap in the support of Wright's model by demonstrating that beta-adrenergic reactivity is associated with incentive value under conditions of unclear difficulty.

Autonomic activation associated with ethanol self-administration in adult female P rats

The present study examined changes in heart rate (HR) prior to and during limited access ethanol drinking in adult female P rats. P rats were implanted with radio-telemetric transmitters to measure HR. Daily testing involved a 90-min pre-test period (water only available) and a subsequent 90-min test period [either water (W) or ethanol available]. After a week of habituation, one ethanol group had access to ethanol for 7 weeks (CE), and another ethanol group had access for 4 weeks, was deprived for 2 weeks and then had access for a final week (DEP). Analyses of HR revealed that CE and DEP rats had significantly higher HR than W rats during test periods that ethanol was present and that DEP rats displayed higher HR during the early test period of the ethanol deprivation interval, as well. These data indicate that ethanol drinking induces HR activation in adult female P rats, and that this activation can be conditioned to the test cage environment, paralleling reports on contextual conditioning and cue-reactivity in alcoholics exposed to alcohol-associated stimuli. Therefore, this behavioral test may prove advantageous in screening pharmacotherapies for reducing craving and relapse, which are associated with cue-reactivity in abstinent alcoholics.

Are the effects of Unreal violent video games pronounced when playing with a virtual reality system?

This study was conducted to analyze the short-term effects of violent electronic games, played with or without a virtual reality (VR) device, on the instigation of aggressive behavior. Physiological arousal (heart rate (HR)), priming of aggressive thoughts, and state hostility were also measured to test their possible mediation on the relationship between playing the violent game (VG) and aggression. The participants--148 undergraduate students--were randomly assigned to four treatment conditions: two groups played a violent computer game (Unreal Tournament), and the other two a non-violent game (Motocross Madness), half with a VR device and the remaining participants on the computer screen. In order to assess the game effects the following instruments were used: a BIOPAC System MP100 to measure HR, an Emotional Stroop task to analyze the priming of aggressive and fear thoughts, a self-report State Hostility Scale to measure hostility, and a competitive reaction-time task to assess aggressive behavior. The main results indicated that the violent computer game had effects on state hostility and aggression. Although no significant mediation effect could be detected, regression analyses showed an indirect effect of state hostility between playing a VG and aggression.

Effect of impulsivity on cardiovascular and subjective reactivity to smoking cues

Individuals with high levels of impulsivity are more likely to smoke and may have greater difficulty quitting than other smokers. Although the specific mechanisms mediating this relationship are not explicitly known, one candidate is disproportionate cigarette craving in response to environmental smoking cues. We assessed the effect of impulsivity on three measures of cue reactivity. Regular smokers (n=75) were exposed to a smoking cue and a neutral cue in 2 counterbalanced experimental sessions. Cigarette craving, heart rate (HR), and mean arterial pressure (MAP) were used to index cue reactivity. More impulsive smokers exhibited a disproportionate response to the smoking cue in terms of MAP (p=.009) but not HR or craving. Impulsive smokers may experience disproportionate cigarette craving in response to environmental smoking cues that are not reflected in self-report measures due to a relative lack of conscious awareness of the urge to smoke.

Anger and fear: Separable effects of emotion and motivational direction on somatovisceral responses

We studied whether emotion (anger vs. fear) and motivational direction (approach vs. withdrawal) have specific, separable, and independent somatovisceral response patterns. Imagination scripts about soccer game episodes with crossed Emotion x Motivational Direction content resulting in four experimental groups were presented to a total of N = 118 active soccer players. Self-reports reflected the emotion but not the motivational direction induction. Univariate and multivariate analyses of 24 somatovisceral variables and 2 a priori defined summary variables showed that anger and fear had specific response profiles with effect sizes correlating r = 0.53 with the respective effect sizes from a previous study. Approach and withdrawal profiles varied only in intensity. Emotion and motivational direction did not interact and had independent somatovisceral effects. Results suggest that anger and fear have separate underlying neurobiological organizations each capable of bi-directional motivational tuning of efferent pathways. Results support the Component Model of Somatovisceral Response Organization.

Relationship between the cardiac response to acute intoxication and alcohol-induced subjective effects throughout the blood alcohol concentration curve

RATIONALE

There is evidence to suggest that individual differences in the subjective response to alcohol exist and exaggerated cardiac response to alcohol has been suggested to be a marker of increased sensitivity to the stimulant properties of alcohol.

OBJECTIVES

The present investigation examines the relationship between cardiac reactivity to alcohol measured on the ascending limb of the Blood Alcohol Concentration (BAC) curve and the subjective stimulant and sedative effects of alcohol throughout the BAC curve.

METHODS

The stimulant and sedative effects of alcohol anticipatory to alcohol and during the ascending and descending limbs of the BAC curve were evaluated using the Biphasic Alcohol Effects Scale in 39 male social drinkers.

RESULTS

Cardiac response to ethanol measured on the ascending limb of the BAC curve was positively correlated with intoxicated stimulant effects at numerous time points during the ascending and descending limbs of the BAC curve (ps < 0.01). No associations were found between cardiac change following alcohol and alcohol-related sedative effects at any time point.

CONCLUSIONS

Objective and subjective reports of stimulation post-alcohol ingestion may increase risk for problematic drinking.

Incentive value, unclear task difficulty, and cardiovascular reactivity in active coping

An experiment with 44 participants assessed the moderating effects of four levels of incentive value on cardiovascular responses in active coping. Randomly assigned to one of four different incentive conditions, participants performed a memory task without knowing its difficulty in advance. By means of successfully performing the task participants could either win no reward, 10 Swiss Francs, 20 Swiss Francs, or 30 Swiss Francs. In accordance with the theoretical predictions derived from motivational intensity theory, reactivity of systolic blood pressure and heart rate monotonically increased with incentive value. Thereby, these findings provide additional empirical evidence for the predictions of motivational intensity theory with regard to unclear task difficulty and extend recent research (Richter, M., Gendolla, G.H.E., 2006. Incentive effects on cardiovascular reactivity in active coping with unclear task difficulty. Int. J. Psychophysiol. 61, 216-225.), which was not conclusive regarding the predicted monotonic relationship between incentive value and cardiovascular reactivity under conditions of unclear task difficulty.

Effects of Conditioned Reward and Nonreward Cues on the Heart Rate Response to Alcohol Intoxication in Male Social Drinkers

BACKGROUND

An exaggerated heart rate (HR) increase following alcohol intoxication has been suggested to reflect sensitivity to alcohol-induced reward. The goal of this study is to verify whether pairing alcohol ingestion with conditioned reward and nonreward cues can influence HR responses to alcohol in previously identified individuals with a low and a high HR response.

METHODS

Fifty-six male social drinkers participated in a 2-day study. On day 1, participants consumed 0.75 g/kg of body weight of pure ethanol. A median split of the alcohol-induced HR responses identified groups of low and high HR responders. On day 2, both groups participated while sober in a computer task where distinct auditory and visual cues were paired either with monetary reward or no monetary reward. Subsequently, participants were randomly assigned to an alcohol challenge, which occurred while they were exposed to either the conditioned cues of reward or to the nonreward cues.

RESULTS

The physiological response to alcohol intoxication on day 2 was compared with alcohol-induced HR responses on day 1 (neutral alcohol challenge) for both low and high HR responders. Paired t-tests showed that high HR responders had significantly decreased alcohol-induced HR responses on day 2 in the nonreward condition when compared with day 1. No other relationships between cardiac responses to alcohol and cue conditions were obtained.

CONCLUSIONS

The rewarding nature of alcohol can be altered by the context in which it is consumed in a subset of individuals who are sensitive to alcohol's stimulating properties.

Dissociation of physiology and behavior in PTSD

We have previously reported that subjects with posttraumatic stress disorder (PTSD) differ from trauma controls in their ability to produce and withhold responses in the Stop-Signal Task depending on the motivational context as determined by financial reward. This experiment measured skin conductance and heart rate to assess autonomic changes accompanying these different patterns of behavior. Fowles hypothesized that heart rate would increase with behavioral activation and that increases in skin conductance would accompany behavioral inhibition. Both PTSD and comparison groups showed the expected behavioral changes in response to rewards, but they differed in their physiological responses. The subjects in the traumatized comparison group showed changes in skin conductance and heart rate consistent with Fowles' hypothesis and the observed changes in behavioral inhibition and activation. However, PTSD subjects showed no significant change in either physiological measure. These results demonstrate a dissociation between autonomic reactivity and motivated behavior in PTSD that may represent one aspect of emotional numbing.

Incentive effects on cardiovascular reactivity in active coping with unclear task difficulty

Two experiments with a total of 96 participants assessed cardiovascular response in active coping. The studies were run in 2x2 designs and manipulated the clarity of task difficulty (clear vs. unclear) and incentive value (low vs. high) of a memory task, which was either easy (Experiment 1) or extremely difficult (Experiment 2). In accordance with the theoretical predictions of motivational intensity theory [Brehm, J.W., Self, E.A., 1989. The intensity of motivation. Annu. Rev. Psychol. 40, 109-131; Wright, R.A., 1996. Brehm's theory of motivation as a model of effort and cardiovascular response. In: Gollwitzer, P.M., Bargh, J.A. (Eds.), The Psychology of Action: Linking Cognition and Motivation to Behaviour, Guilford, New York, pp. 424-453], systolic reactivity varied directly with incentive value when task difficulty was unclear. In contrast, when task difficulty was clear, incentives had no influence and cardiovascular reactivity was low. These findings provide the first evidence for the predictions of motivational intensity theory with regard to unclear task difficulty and complete past research that has focused on the effects of fixed and unfixed task difficulty on cardiovascular reactivity.

Agentic extraversion modulates the cardiovascular effects of the dopamine D2 agonist bromocriptine

A recent psychobiological theory postulates a dopaminergic basis for the agency facet of extraversion, leading to the prediction that this personality trait modulates the psychophysiological effects of dopaminergic drugs. A single dose of the dopamine D2 receptor agonist bromocriptine reduces blood pressure in healthy volunteers. However, it is currently unknown whether this hypotensive effect of bromocriptine is modulated by agentic extraversion. Therefore, we measured resting cardiovascular activation in groups of healthy male volunteers either high or low in agentic extraversion, either under bromocriptine (1.25 mg) or placebo. Focusing the analyses on activation components derived from 18 cardiovascular variables, we found that bromocriptine reduces alpha-adrenergic activation in the sample as a whole, whereas the effects on beta-adrenergic and cholinergic activation are modulated by agentic extraversion.