Combined Effects of Glucocorticoid and Noradrenergic Activity on Loss Aversion

Noradrenergic modulation of stress induced catecholamine release: Opposing influence of FG7142 and yohimbine

Life stress modulates decision making, particularly in the face of risk, in some cases prompting vulnerable populations to make suboptimal, life-altering choices. In the brain, stress is known to alter the extracellular release of catecholamines in structures such as basolateral amygdala (BLA) and nucleus accumbens (NAc), but the relationship between catecholamines and decision-making behavior under stress has not been systemically explored. We developed an operant touchscreen decision-making task for rats comprising elements of loss aversion and risk seeking behavior. Rats were first injected systemically with an adrenergic α2A-receptor agonist (guanfacine) and antagonist (yohimbine), as well as a partial inverse GABAA agonist, FG 7142, known to induce anxiety and stress related physiological responses in a variety of species, including humans. We then used fiber photometry to monitor NE in the basolateral amygdala (BLA), and DA activity in the nucleus accumbens (NAc) while animals engaged in decision-making and following systemic injections of FG 7142 and yohimbine. We found that neither yohimbine nor guanfacine had any impact on decision making strategy but altered motivational state with yohimbine making the animal almost insensitive to the reward outcome. The pharmacological induction of stress with FG 7142 biased the rats' decisions towards safety, but this bias shifted towards risk when co-treated with yohimbine. In the BLA and NAc, FG 7142 altered catecholamine release with systemic yohimbine producing opposing effects on NE and DA release. These findings highlight the catecholamine basis of loss aversion and neuromodulation of critical brain structures during stress through α2A adrenoreceptors.

Acute stress differentially influences risky decision-making processes by sex: A hierarchical bayesian analysis

How does stress influence our decision-making? Although numerous studies have attempted to answer this question, their results have been inconsistent-presumably due to methodological heterogeneity. Drawing on cumulative prospect theory, we examined how acute stress influenced risky decision-making. To this end, we randomly assigned 147 participants to an acute stress induction or control condition and subsequently assessed participants' risky decision-making. We found that stress increased risky decision-making overall, but more importantly, that stress exerted multiple effects on risky decision-making processes that differed between male and female participants. For female participants, relative to the control condition, stress produced a pattern of decision-making characterized by risk seeking with respect to gains, slightly reduced loss aversion, accurate outcome probability assessment, and greater choice stochasticity. For male participants, stress, relative to the control condition, produced to a pattern of decision-making characterized by very low loss aversion and poorer outcome probability assessment. These results suggest that some of the heterogeneity in existing literature may be explainable by task differences in risk type, risk amount, and outcome certainties, and further that these effects will differ by sex. In short, stress changes how we make decisions, and it does so differently by sex.

Late acute stress effects on decision-making: The magnified attraction to immediate gains in the iowa gambling task

Previous literature indicates that the later phases of the acute stress response may promote poor decision-making, characterized by riskier choices and a likely inclination towards immediate reward-seeking. However, all studies addressing the effect of this phase have treated decisional capacity as a singular dimension, without analyzing the underlying processes under decision-making. Employing the Value-Plus-Perseveration (VPP) RL model, based on Bayesian logic, this study aims to gain specific insights into how late phase of acute stress impacts the cognitive processes underpinning decision-making in the Iowa Gambling Task (IGT), deciphering whether, as expected, gains are processed in a magnified manner. Seventy-three participants were randomly assigned to two groups, stress (N = 35) and control (N = 38). A virtual version of The Trier Social Stress Test (TSST-VR) was employed as a laboratory stressor. Decision-making was evaluated 35 minutes after the stressor onset, by means of the IGT. Results showed that stressed participants, in comparison to control group, displayed more perseverant and consistent decision-making, enhanced memory, and reinforcement learning capabilities, yet were guided by a greater attraction to decks offering immediate high gains. These results are analyzed with the understanding that in the IGT, short-term decisions focused on instant rewards are seen as counterproductive. This suggests that stress could limit the ability to switch to strategies that are more cautious and offer greater long-term benefits.

Basal cortisol level modulates stress-induced opioid-seeking behavior

In preclinical studies and our human laboratory, the α2-noradrenergic autoreceptor antagonist yohimbine was found to promote drug-seeking behavior. This study evaluated effects of dose-combinations of yohimbine and the glucocorticoid receptor agonist hydrocortisone to model intensity-dependent effects of stimulating each neurochemical system, alone and together, on stress-reactivity and opioid-seeking. Twelve regular heroin-using participants diagnosed with opioid use disorder (OUD) were stabilized on sublingual buprenorphine (8-mg/day), then passed a hydromorphone 18-mg vs. placebo intramuscular reinforcement screen. Across 9 experimental conditions (3 × 3 within-subject, randomized crossover, placebo-controlled, double-blind design) during inpatient buprenorphine maintenance, combinations of oral pretreatment doses of yohimbine (0, 27, 54-mg; t = 0 min) then hydrocortisone (0, 20, 40-mg; t = 45 min) were administered. In each condition, subjective drug and mood effects, cardiovascular responses, and saliva cortisol and α-amylase levels were assessed to evaluate stress-reactivity, and participants completed a 12-trial choice progressive ratio task during which they could earn units of hydromorphone (1.5-mg intramuscular) and/or money ($2.00). Yohimbine dose-dependently increased blood pressure, α-amylase, and anxiety scores, and decreased opioid agonist symptoms; hydrocortisone dose-dependently increased cortisol levels. Yohimbine/hydrocortisone dose-combinations significantly shifted within-session responding from money to opioid-seeking among participants with lower basal cortisol levels. These findings replicate yohimbine effects on stress biomarkers and demonstrate that noradrenergic/glucocorticoid-potentiated opioid-seeking is modulated by basal cortisol level. In persons with OUD stabilized on buprenorphine, basal HPA-axis activity and acute stressors can enhance opioid relative reinforcing efficacy. These factors may limit OUD treatment efficacy and highlight the need for novel interventions that prevent stress-induced opioid-seeking.

Do stress hormones influence choice? A systematic review of pharmacological interventions on the HPA axis and/or SAM system

The hypothalamus-pituitary-adrenal axis (HPA axis) and the sympathetic-adrenal-medullary system (SAM system), two neuroendocrine systems associated with the stress response, have often been implicated to modulate decision-making in various domains. This systematic review summarizes the scientific evidence on the effects of pharmacological HPA axis and SAM system modulation on decision-making. We found 6375 references, of which 17 studies fulfilled our inclusion criteria. We quantified the risk of bias in our results with respect to missing outcome data, measurements, and selection of the reported results. The included studies administered hydrocortisone, fludrocortisone (HPA axis stimulants), yohimbine, reboxetine (SAM system stimulants), and/or propranolol (SAM system inhibitor). Integrating the evidence, we found that SAM system stimulation had no impact on risk aversion, loss aversion or intertemporal choice, while SAM system inhibition showed a tentative reduction in sensitivity to losses. HPA axis stimulation had no effect on loss aversion or reward anticipation but likely a time-dependent effect on decision under risk. Lastly, combined stimulation of both systems exhibited inconsistent results that could be explained by dose differences (loss aversion) and sex differences (risk aversion). Future research should address time-, dose-, and sex-dependencies of pharmacological effects on decision-making.

Decision-making under stress: A psychological and neurobiological integrative model

Understanding the impact of stress on cognitive processes, particularly decision-making, is crucial as it underpins behaviors essential for survival. However, research in this domain has yielded disparate results, with inconsistencies evident across stress-induction paradigms and drug administration protocols designed to investigate specific stress pathways or neuromodulators. Building upon empirical studies, this research identifies a multifaceted matrix of variables contributing to the divergent findings. This matrix encompasses factors such as the temporal proximity between stressors and decision tasks, the nature of stressors and decision contexts, individual characteristics including psychobiological profiles and affective states at the time of decision-making and even cultural influences. In response to these complexities, we propose a comprehensive model that integrates these relevant factors and their intricate interplay to elucidate the mechanisms governing decision-making during stressful events. By synthesizing these insights, our model not only refines existing paradigms but also provides a framework for future study designs, offering avenues for theoretical advancements and translational developments in the field of stress's impact on cognitive functions. This research contributes to a deeper understanding of the nuanced relationship between stress and decision-making, ultimately advancing our knowledge of cognitive processes under challenging conditions.

Noradrenergic modulation of stress induced catecholamine release: Opposing influence of FG7142 and yohimbine

Background

Life stress modulates decision making, particularly in the face of risk, in some cases prompting vulnerable populations to make suboptimal, life-altering choices. In the brain, stress is known to alter the extracellular release of catecholamines in structures such as basolateral amygdala (BLA) and nucleus accumbens (NAc), but the relationship between catecholamines and decision-making behavior under stress has not been systemically explored.

Methods

We developed an operant touchscreen decision-making task for rats comprising elements of loss aversion and risk seeking behavior. Rats were first injected systemically with an adrenergicα 2 A -receptor agonist (guanfacine) and antagonist (yohimbine), as well as a partial inverse GABAA agonist, FG 7142, known to induce anxiety and stress related physiological responses in a variety of species, including humans. We then used fiber photometry to monitor NE in the basolateral amygdala (BLA), and DA activity in the nucleus accumbens (NAc) while animals engaged in decision-making and following systemic injections of FG 7142 and yohimbine.

Results

Neither yohimbine nor guanfacine had any impact on decision making strategy but altered motivational state with yohimbine making the animal almost insensitive to the reward outcome. The pharmacological induction of stress with FG 7142 biased the rats' decisions towards safety, but this bias shifted toward risk when co-treated with yohimbine. In the BLA and NAc, the FG 7142 altered catecholamine release, with systemic yohimbine producing opposing effects on NE and DA release.

Conclusions

Stress induced changes in catecholamine release in the BLA and NAc can directly influence loss sensitivity, decisions and motivation, which can be modulated by theα 2 A adrenoreceptor antagonist, yohimbine.

Acute stress promotes effort mobilization for safety-related goals

Although the acute stress response is a highly adaptive survival mechanism, much remains unknown about how its activation impacts our decisions and actions. Based on its resource-mobilizing function, here we hypothesize that this intricate psychophysiological process may increase the willingness (motivation) to engage in effortful, energy-consuming, actions. Across two experiments (n = 80, n = 84), participants exposed to a validated stress-induction protocol, compared to a no-stress control condition, exhibited an increased willingness to exert physical effort (grip force) in the service of avoiding the possibility of experiencing aversive electrical stimulation (threat-of-shock), but not for the acquisition of rewards (money). Use of computational cognitive models linked this observation to subjective value computations that prioritize safety over the minimization of effort expenditure; especially when facing unlikely threats that can only be neutralized via high levels of grip force. Taken together, these results suggest that activation of the acute stress response can selectively alter the willingness to exert effort for safety-related goals. These findings are relevant for understanding how, under stress, we become motivated to engage in effortful actions aimed at avoiding aversive outcomes.

Logical decisions after a psychosocial stressor: The late phase of acute stress reduces loss aversion

Loss aversion, the principle that losses have a greater impact on decision-making than gains, can be modulated by stress. Most findings reported that stress reduces loss aversion, in line with the alignment hypothesis. Yet, decision-making was always assessed at the early stages of the stress response. Instead, the latter phase of the stress response enhances the salience-network and then, it could amplify the salience of losses, thereby increasing loss aversion. To our knowledge, it has never been studied how the latter stress response influences loss aversion and our aim is to fill this gap. 92 participants were divided into experimental and control group. The first one was exposed to the Trier Social Stress Test, and controls viewed a match-length distractor video. Both groups performed a mixed gamble task to measure loss aversion through a Bayesian-computational model. During and after the stressor, experimental group exhibited signs of both physiological and psychological stress which indicated that stress induction was effective. However, rather than increasing, loss aversion of stressed participants was lower. These results constitute a new evidence of stress influencing loss aversion and are discussed within the alignment hypothesis, according to which stress aligns sensitivity to gains and losses.

COVID-19 stressor reduces risk taking: the role of trait interoception

The Framing Effect (FE) demonstrated that the way two alternatives are displayed affects people's inclination to make a specific choice, showing a risk aversion when alternatives are displayed on positive frames and risk seeking in negative frames. Risk seeking in negative frames is closely linked to loss aversion. Moreover, classical research and the salience-of-losses hypothesis argues that stress may enhance the FE and loss aversion. Recent studies also suggest that the trait interoception and alexithymia could interact and moderate the framing susceptibility. However, experimental paradigms on stress could ignore variables such as threat perception. In this sense, COVID-19 pandemic has become a powerful real-life stressor in many countries. We aimed to study how real-life stressors influence decision-making under risk. A total of 97 participants were divided into a control (n = 48) and an experimental group (n = 49). The experimental group were exposed to a stressor manipulation, a 5 min COVID-19 lockdown documentary. Our results show that COVID-19-related stressors significantly decreased bet acceptance regardless of the frame, also reducing loss aversion. Moreover, interoception was a significant predictor of loss aversion under stress conditions. Our results do not support classical research on stress and FE.

The effects of hydrocortisone and yohimbine on human behavior in approach-avoidance conflicts

RATIONALE

Balancing approach of positive and avoidance of negative stimuli is essential when faced with approach-avoidance conflicts, e.g., situations with both positive and negative outcomes. This balance is disturbed in several mental disorders, e.g., excessive avoidance in anxiety disorders, and heightened approach in substance use disorders. Since stress is assumed to impact these disorders' etiology and maintenance, it seems crucial to understand how stress influences behavior in approach-avoidance conflicts. Indeed, some studies suggested altered approach-avoidance behavior under acute stress, but the mechanism underlying these effects is unknown.

OBJECTIVES

Investigate how the pharmacological manipulation of major stress mediators (cortisol and noradrenaline) influences task-based approach-avoidance conflict behavior in healthy individuals.

METHODS

Ninety-six participants (48 women, 48 men) received either 20mg hydrocortisone, 20mg yohimbine, both, or placebo before performing a task targeting foraging under predation in a fully crossed double-blind between-subject design. Moreover, we investigated effects of gender and endogenous testosterone and estradiol levels on approach-avoidance behavior.

RESULTS

While biological stress markers (cortisol concentration, alpha amylase activity) indicated successful pharmacological manipulation, behavior in approach-avoidance conflicts was not affected as expected. Although yohimbine administration affected risky foraging latency under predation, we found no main effect of hydrocortisone or their interaction on behavior. In contrast, we found gender differences for almost all behavioral outcome measures, which might be explained by differences in endogenous testosterone levels.

CONCLUSIONS

The investigated major stress mediators were not sufficient to imitate previously shown stress effects on approach-avoidance conflict behavior. We discuss potential reasons for our findings and implications for future research.

Later stages of acute stress impair reinforcement-learning and feedback sensitivity in decision making

Whereas the effects of the early stages of acute stress seem to improve learning and increase loss aversion in decision making, in later stages, the opposite has been found, an impairment in decision making probably due to higher reward-attraction, as the STARS approach suggests. This study aims to investigate the effects of the later stages of acute stress on decision making and its underlying processes using a computational model. We hypothesized that stress would affect underlying cognitive strategies during decision making. Ninety-five participants were randomly distributed into two groups, experimental (N = 46) and control (N = 49). A virtual version of The Trier Social Stress Test (TSST) was used as a laboratory stressor. After 20minutes, decision making was assessed by using the Iowa Gambling Task (IGT). The Value-Plus-Preservation (VPP) RL computational model was used to extract decision-making components. As expected, the stressed participants showed deficits in IGT performance on reinforcement-learning and feedback sensitivity. However, there was no gains attraction. These results are discussed by considering that decision making in later stages of acute stress could be based on impairments in prefrontal cortex functioning.

The Effects of Citalopram and Thalamic Dopamine D2/3 Receptor Availability on Decision-Making and Loss Aversion in Alcohol Dependence

Selective serotonin reuptake inhibitors (SSRIs) are commonly prescribed for patients who misuse alcohol, especially in the context of comorbid depressive symptoms. Deficits in impulse control and decision-making are linked to routine alcohol consumption and alcohol dependence. The goal of this study was to determine the effects of a single dose of citalopram on measures of impulsivity, decision-making, and/or brain dopamine receptor availability in alcohol-dependent individuals. A double-blind, placebo-controlled, within-subject, outpatient study was conducted with active alcohol-dependent (DSM-IV-TR criteria) participants (n = 12) and matched healthy controls (n = 13). Serial doses of both citalopram (40 mg) and saline were administered intravenously before laboratory tests of decision-making (Balloon Analogue Risk Task, delay discounting task, and Loss Aversion Gambling Task) and positron emission tomography with [¹⁸F]-fallypride to measure dopamine D_2/3 receptor availability, separated by at least one week. Alcohol-dependent participants demonstrated greater loss aversion than healthy controls, but there were no group differences in risk taking on the Balloon Analogue Risk Task. Citalopram increased delay discounting across groups, with no group difference in the effect. There were no effects of citalopram on risk taking on the Balloon Analogue Risk Task. PET showed a negative correlation between thalamic dopamine D_2/3 receptor availability and loss aversion across groups. The effect of citalopram to decrease the valuation of monetary reward as a function of delay raises the possibility that SSRIs can influence risky decision-making in clinical populations. In addition, these results suggest that altered thalamic dopamine signaling may play an important role in disproportionately valuing losses in patients with Alcohol Use Disorder. This trial is registered under ClinicalTrials.gov registration NCT01657760.

Stressed individuals exhibit pessimistic bursting beliefs and a lower risk preference in the balloon analogue risk task

Stress alters decision-making by usually promoting risk-taking and reward-seeking, which could be advantageous in a context where risk is rewarded, such as the Balloon Analogue Risk Task (BART). However, previous studies addressing this issue showed inconsistencies which could emerge from assessing decision-making as a single dimension. Our aim is to study through computational modelling how stress influences cognitive subprocesses of the decision-making during the BART. For this purpose, 94 healthy participants were submitted to BART, but only half were exposed to the virtual Trier Social Stress Test (TSST-VR). The Experimental-Weight Mean-Variance (EWMV) model was used to gain insight into the subprocesses involved in risk-taking during BART. Rather than reward-seeking, our results showed a pessimistic prior belief about the balloons bursting likelihood, and a lower risk preference in the stressed participants. This cautious attitude could be attributable to an alertness state promoted by stress. Yet, since risk is rewarded in BART, it could also evidence a maladaptive decision-making derived from learning difficulties and altered feedback-processing under stress.

Emotional stress & decision-making: an emotional stressor significantly reduces loss aversion

Stress influences loss aversion, the principle that losses loom larger than gains, although the nature of this relationship is unclear. Studies show that stress reduces loss aversion; however, stress response has been only studied by means of physiological measures, but the stressor emotional impact remained unclear. Since emotions can modify stress response and increase the activity of the loss aversion neural substrates, it could be expected that an emotional stressor may produce the opposite effect, i.e. loss aversion increase. 69 participants were divided into experimental and control group. The first one was exposed to emotional stress through a 5-minutes video, and control group viewed a match-length distractor video. Physiological stress response was assessed by means of electrodermal activity (EDA), and both perceived stress, and negative affect (i.e. psychological stress response) were registered through questionnaires. Both groups performed a mixed gamble task, which allowed the extraction of loss aversion through a Bayesian-computational model. During and after video, experimental group had higher electrodermal activity, perceived stress, and negative affect than controls, suggesting that emotional stress induction was effective. However, rather than increasing, loss aversion of stressed participants was lower. These results constitute a new evidence of emotional stress influencing loss aversion and highlight that stress, regardless of its emotional impact, can reduce this phenomenon. These results should be considered when predicting risky decisions.

Three Theories of Choice and Their Psychology of Losses

Loss aversion has long been regarded as a fundamental psychological regularity, yet evidence has accumulated to challenge this conclusion. We review three theories of how people make decisions under risk and, as a consequence, value potential losses: expected-utility theory, prospect theory, and risk-sensitivity theory. These theories, which stem from different behavioral disciplines, differ in how they conceptualize value and thus differ in their assumptions about the degree to which value is dependent on state and context; ultimately, they differ in the extent to which they see loss aversion as a stable individual trait or as a response to particular circumstances. We highlight points of confusion that have at least partly fueled the debate on the reality of loss aversion and discuss four sources of conflicting views: confusion of loss aversion with risk aversion, conceptualization of loss aversion as a trait or as state dependent, conceptualization of loss aversion as context dependent or independent, and the attention-aversion gap-the observation that people invest more attentional resources when evaluating losses than when evaluating gains, even when their choices do not reveal loss aversion.

The effects of acute and chronic stress on choice consistency

Important decisions are often made under some degree of stress. It is now well-established that acute stress affects preferences and priorities in our decisions. However, it is hard to make a general case on the net impact of stress on decision-making quality in a normative sense as evidence for or against a direct effect of stress on decision-making quality is sparse. Here, we used the revealed preference framework of choice consistency to investigate decision-making quality without the assumption of an objectively correct choice. Specifically, we tested whether acute stress influences choice consistency in a time dependent fashion. A sample of 144 participants solved a food choice task before, immediately after and in the aftermath of the Trier Social Stress Test (TSST) or a matched control procedure. We confirmed the effectiveness of our stress manipulation via an array of subjective and physiological stress measures. Using Bayesian statistics, we found strong evidence against an effect of acute stress on choice consistency. However, we found exploratory evidence for a negative association of self-reported chronic stress and choice consistency. We discuss our results in the context of previous findings of stress effects on choice consistency and preference changes.

The effect of testosterone on economic risk-taking: A multi-study, multi-method investigation

Testosterone has been suggested to influence individuals' economic decision making, yet the effects of testosterone on economic behavior are not well-understood and existing research is equivocal. In response, in three studies, we examined the extent to which testosterone affected or was associated with several different facets of economic decision making. Study 1 was a double-blind, placebo-controlled, within-subjects study examining loss aversion and risk-taking (N = 26), whereas Study 2 was a larger double-blind, placebo-controlled, between-subjects study examining loss aversion and risk-taking behavior (N = 117). As a methodological compliment, Study 3 was a larger correlational design (N = 213) with a highly accurate measure of endogenous testosterone examining a wider range of economic behaviors and trait-like preferences. Broadly, the results of all three studies suggest no consistent relationship between testosterone and financial behavior or preferences. Although there were significant effects in specific cases, these findings did not replicate in other studies or would not remain significant when controlling for family-wise error rate. We consider potential contextual moderators that may determine under what circumstances testosterone affects economic decision making.

Risk sensitivity and theory of mind in human coordination

What humans do when exposed to uncertainty, incomplete information, and a dynamic environment influenced by other agents remains an open scientific challenge with important implications in both science and engineering applications. In these contexts, humans handle social situations by employing elaborate cognitive mechanisms such as theory of mind and risk sensitivity. Here we resort to a novel theoretical model, showing that both mechanisms leverage coordinated behaviors among self-regarding individuals. Particularly, we resort to cumulative prospect theory and level-k recursions to show how biases towards optimism and the capacity of planning ahead significantly increase coordinated, cooperative action. These results suggest that the reason why humans are good at coordination may stem from the fact that we are cognitively biased to do so.

We propose a new computational model characterizing coordination among self-regarding individuals under theory of mind and risk sensitivity. Theory of mind enables decision-making based on the attribution of beliefs, knowledge, or goals to others, whereas different risk sensitivities allows one to assess the impact of different ways of valuing uncertain returns, as captured by descriptive theories from social-economic studies. Together they provide evidence that biases towards optimism, and the capacity for planning ahead, significantly increase coordinated, cooperative action.

Genetic underpinnings of risky behaviour relate to altered neuroanatomy

Previous research points to the heritability of risk-taking behaviour. However, evidence on how genetic dispositions are translated into risky behaviour is scarce. Here, we report a genetically informed neuroimaging study of real-world risky behaviour across the domains of drinking, smoking, driving and sexual behaviour in a European sample from the UK Biobank (N = 12,675). We find negative associations between risky behaviour and grey-matter volume in distinct brain regions, including amygdala, ventral striatum, hypothalamus and dorsolateral prefrontal cortex (dlPFC). These effects are replicated in an independent sample recruited from the same population (N = 13,004). Polygenic risk scores for risky behaviour, derived from a genome-wide association study in an independent sample (N = 297,025), are inversely associated with grey-matter volume in dlPFC, putamen and hypothalamus. This relation mediates roughly 2.2% of the association between genes and behaviour. Our results highlight distinct heritable neuroanatomical features as manifestations of the genetic propensity for risk taking.

Heart rate variability after vigorous physical exercise is positively related to loss aversion

BACKGROUND AND OBJECTIVES OF THE ARTICLE

Loss aversion bias, whereby losses loom larger than gains, can be reduced by stress. At the same time, vigorous physical exercise is a powerful neuroendocrine stressor and heart rate variability (HRV) provides an objective measure of the actual exercise impact, relative to each individual physical condition. Our aim was to study whether vigorous exercise can influence loss aversion, considering HRV in this relation. We hypothesized that the lower HRV derived from vigorous exercise (i.e., when stressor produced the most impact) would predict a lower loss aversion.

METHODS

Two groups (Experimental, N = 37; Control, N = 39) completed a loss aversion task, but the experimental group was exposed to an acute physical stressor before.

RESULTS

Results revealed a significant group x HRV interaction. In the control group, HRV was not associated with loss aversion. Conversely, as hypothesized, the lower HRV levels derived from exercise were associated with a lesser loss aversion in the experimental group.

CONCLUSIONS

Results suggest that physiological changes from physical exercise could affect decision-making by reducing loss aversion.

Noradrenergic system and cognitive flexibility: Disentangling the effects of depression and childhood trauma

Stress plays a fundamental role in the development and maintenance of major depressive disorder (MDD). Importantly, maladaptive changes in the physiological stress regulation systems have been demonstrated. In the locus coeruleus-noradrenergic (LC-NA) system, up-regulated central alpha2-adrenergic receptors in patients with MDD affect cognitive functions. Although cognitive deficits are core symptoms of MDD, the relationship between the LC-NA system and cognitive processes has rarely been investigated in depressed patients. The aim of our study was to investigate whether noradrenergic stimulation affects cognitive flexibility in MDD. In addition, we aimed to further disentangle the effects of MDD and adverse childhood experiences (ACE), such as physical or sexual abuse on cognitive function. In a double-blind placebo-controlled study, MDD patients with ACE, MDD patients without ACE, healthy participants with ACE and healthy control participants without MDD or ACE were tested with a task switching task (total N = 125). Participants were tested twice after treatment with either 10 mg yohimbine or a placebo. Switch costs (differences between switch and repetition trials) in reaction times and accuracy served as the independent variables. We found higher switch costs in MDD patients as compared with controls, while ACE did not affect task performance. Yohimbine administration had no effect on task switching. The results of this study contribute to a better understanding of the role of the LC-NA system as a neurobiological mechanism of cognitive processes in patients with MDD.

Effects of hydrocortisone and yohimbine on decision-making under risk

INTRODUCTION

Many studies have investigated the influence of stress on decision-making. However, results are equivocal and the exact role of increased noradrenaline and cortisol after stress remains unclear. Using pharmacological manipulation, we investigated the influence of noradrenergic and glucocorticoid activity on risky decision-making in a gambling task that included mixed-gamble trials (gains and losses are possible) and gain-only trials.

METHODS AND MATERIALS

One hundred-and-four healthy young men participated in our randomized, double-blind, placebo-controlled, between-group study. Participants were randomly assigned to one of four groups: (A) yohimbine, (B) hydrocortisone, (C) yohimbine and hydrocortisone, or (D) placebo. Frequency of risky choices, i.e., monetary risk taking, was the dependent variable. We also investigated the influence of hydrocortisone and yohimbine on loss aversion, which is the tendency to overweigh losses compared with gains.

RESULTS

Participants chose the risky option less often after receiving hydrocortisone compared with no hydrocortisone. This effect was strongest in the gain-only trials. Yohimbine had no effect. Loss aversion was not affected by hydrocortisone or yohimbine.

DISCUSSION

Decreased reward processing may explain the reduction of risk taking by hydrocortisone in gain-only trials. The effects of stress hormones on different decision-related constructs and processes hence require further investigation.

Does testosterone impair men's cognitive empathy? Evidence from two large-scale randomized controlled trials

The capacity to infer others' mental states (known as 'mind reading' and 'cognitive empathy') is essential for social interactions across species, and its impairment characterizes psychopathological conditions such as autism spectrum disorder and schizophrenia. Previous studies reported that testosterone administration impaired cognitive empathy in healthy humans, and that a putative biomarker of prenatal testosterone exposure (finger digit ratios) moderated the effect. However, empirical support for the relationship has relied on small sample studies with mixed evidence. We investigate the reliability and generalizability of the relationship in two large-scale double-blind placebo-controlled experiments in young men (n = 243 and n = 400), using two different testosterone administration protocols. We find no evidence that cognitive empathy is impaired by testosterone administration or associated with digit ratios. With an unprecedented combined sample size, these results counter current theories and previous high-profile reports, and demonstrate that previous investigations of this topic have been statistically underpowered.

Delayed effects of psychosocial stress on risk taking

Several studies found that acute stress leads to increased risk taking in humans. However, this effect appears to be time-dependent because the few studies that examined delayed (>40 min after stress onset) stress effects show in fact a decrease in risk taking. In 32 young healthy women, we intra-individually examined whether psychosocial stress decreases risk taking 80 min after stress induction. All participants performed the Balloon Analog Risk Task (BART) twice: once after exposure to the Trier social stress test (TSST) and once after a control condition Placebo-TSST (P-TSST). The experimental order was randomized across participants. The psychophysiological stress response increased after the TSST compared to the P-TSST, indicated by elevated cortisol concentrations, elevated alpha-amylase activity, and elevated blood pressure. We found a significant interaction of stress condition and experimental order. Compared to the control condition psychosocial stress decreased risk taking in novel decision situations but not when participants were already familiar with the BART from the prior condition. Delayed effects of psychosocial stress lead to a decrease in risk taking in unfamiliar but not familiar conditions 80 min after stress exposure. Lay summary It has been suggested that stress exerts delayed effects on risk taking propensity. We found that individuals who are exposed to psychosocial stress take less risk when confronted with novel decisions even 80 min after the stressor compared to individuals who are not stressed.

The endowment effect in the genes: An exploratory study

The endowment effect is a well-documented decision phenomenon, referring to a tendency that people price a commodity higher when selling it than when buying it. This phenomenon can be interpreted as a sort of inertia, an unwillingness to make a change, or in other words an attachment to the status-quo. People with autism dislike social interaction, and are thus probably less willing to buy and sell items and more attached to the status quo. Previous research revealed that T-carriers of a single-nucleotide polymorphism (SNP) of the dopamine beta-hydroxylase (DBH) gene, rs1611115 (C-1021T), are associated with autism and difficulty in social interaction. Therefore, rs1611115 may modulate the endowment effect. In the current study, the subjects sold and bought lotteries with various probabilities of winning money and provided saliva for genotyping. We found that T-carriers (people of CT genotype in this study) exhibited greater endowment effects compared to people of CC genotype. We discuss another two possible explanations of our results: empathy and loss aversion. This is the first attempt to research the endowment effect from the perspective of genes. The result indicates that an SNP of genes (an innate factor) can exert an observable effect on human market activities.

Predicting the behavioural tendency of loss aversion

Loss aversion manifests itself in rejecting a gamble of gaining or losing the same amount of money with equal chance. Although loss aversion is a well-known and intensively studied phenomenon, whether individual differences in behavioural loss aversion can be predicted using scalp potentials (EEG) remains unclear. The current study measured scalp potential when subjects played a series of fair coin-toss games in three situations (high, medium and low loss conditions). We found that most people chose to bet in the low loss condition and avoided to bet in the high loss condition. However, their betting behaviour in the medium loss condition was variable, reflecting their different behavioural tendency of loss aversion. We found that late positive complex (LPC) significantly increased when subjects accepted gambles in the low loss condition (implying potential loss), relative to when they rejected gambles in the high loss condition (implying no gain and no loss), which is consistent with the previous finding that emotional stimuli can induce enhanced LPC. We further found that the difference in the scalp potentials from the above two conditions could predict behavioural tendency of loss aversion in the medium loss condition across subjects. This result demonstrated how behavioural tendency in a situation can be predicted using EEG from other situations.

Influence of glucocorticoid and mineralocorticoid receptor stimulation on task switching

The influence of stress on executive functions has been demonstrated in numerous studies and is potentially mediated by the stress-induced cortisol release. Yet, the impact of cortisol on cognitive flexibility and task switching in particular remains equivocal. In this study, we investigated the influence of pharmacological glucocorticoid receptor (GR) and mineralocorticoid receptor (MR) stimulation, two corticosteroid receptor types known to be responsible for cortisol effects on the brain. We conducted two experiments, each with 80 healthy participants (40 women and 40 men), and tested the effect of the unspecific MR/GR agonist hydrocortisone (Experiment I) and the more specific MR agonist fludrocortisone (Experiment II) on switch costs and task rule congruency in a bivalent, cued task switching paradigm. The results did not confirm our hypotheses; we found no significant effects of our manipulations on task switching capacity, although general switching and congruency effects were observed. We discuss the absence of MR/GR-mediated effects and propose alternative mechanisms that could explain stress induced effects on task switching.

Testosterone, Cortisol and Financial Risk-Taking

Both testosterone and cortisol have major actions on financial decision-making closely related to their primary biological functions, reproductive success and response to stress, respectively. Financial risk-taking represents a particular example of strategic decisions made in the context of choice under conditions of uncertainty. Such decisions have multiple components, and this article considers how much we know of how either hormone affects risk-appetite, reward value, information processing and estimation of the costs and benefits of potential success or failure, both personal and social. It also considers how far we can map these actions on neural mechanisms underlying risk appetite and decision-making, with particular reference to areas of the brain concerned in either cognitive or emotional functions.

Dissociable roles of glucocorticoid and noradrenergic activation on social discounting

People often exhibit prosocial tendencies towards close kin and friends, but generosity decreases as a function of increasing social distance between donor and recipient, a phenomenon called social discounting. Evidence suggests that acute stress affects prosocial behaviour in general and social discounting in particular. We tested the causal role of the important stress neuromodulators cortisol (CORT) and noradrenaline (NA) in this effect by considering two competing hypotheses. On the one hand, it is possible that CORT and NA act in concert to increase generosity towards socially close others by reducing the aversiveness of the cost component in costly altruism and enhancing the emotional salience of vicarious reward. Alternatively, it is equally plausible that CORT and NA exert dissociable, opposing effects on prosocial behaviour based on prior findings implicating CORT in social affiliation, and NA in aggressive and antagonistic tendencies. We pharmacologically manipulated CORT and NA levels in a sample of men (N = 150) and found that isolated hydrocortisone administration promoted prosocial tendencies towards close others, reflected in an altered social discount function, but this effect was offset by concurrent noradrenergic activation brought about by simultaneous yohimbine administration. These results provide inceptive evidence for causal, opposing roles of these two important stress neuromodulators on prosocial behaviour, and give rise to the possibility that, depending on the neuroendocrine response profile, stress neuromodulator action can foster both tend-and-befriend and fight-or-flight tendencies at the same time.