Chronic sleep restriction is a common phenomenon in the real world, yet its impact on how individuals learn and adapt to dynamic patterns of reward in uncertain environments are not well understood. The present study examined how sleep restriction alters the cognitive mechanisms underlying sequential updating, defined as the process by which individuals revise beliefs over time in response to outcome feedback. Thirty-six healthy adults completed two conditions in counterbalanced order: well-rested (seven nights of 9 h time-in-bed) and sleep restriction (seven nights of 5 h time-in-bed). On the final day of each condition, participants performed a probabilistic reversal learning task, requiring flexible behavioral adjustments in response to changing reward contingencies. Computational models grounded in reinforcement learning and Bayesian frameworks were fitted to trial-level data using hierarchical Bayesian estimation. Our model comparison indicated the Asymmetric Rescorla–Wagner model best accounted for behavior, indicating feedback-driven updating with distinct learning rates for reward and nonreward outcomes on the probabilistic reversal learning task. Importantly, sleep restriction increased sensitivity to reward feedback and choice stochasticity, indicating greater reward-chasing behavior and less goal-directed decision making under sleep restriction. Trial accuracy did not differ between conditions. These findings diverge from previous evidence indicating reduced sensitivity toward negative outcomes following short-term sleep restriction, pointing to possible dose-dependent sleep restriction effects and those arising from differences in task requirements. Our findings may have practical implications for decision quality in real-world domains where performance depends on optimal feedback-based updating under uncertain decision environments. Statement of Significance While sleep loss is known to affect decision making, little is understood about how it impacts people’s ability to learn from experience over time. In many real-world situations, like financial trading and medical contexts, optimized decisions rely on updating beliefs and strategies based on incoming feedback. In this study, we show after one week of sleep restriction, individuals became more influenced by rewards and demonstrated increased choice randomness. This suggests they were more likely to chase immediate gains but had difficulty sustaining consistent decision strategies. These findings help explain how sleep restriction can undermine learning and flexible decision making when faced with uncertainty, and carry implications for performance and accountability in roles where repeated, high-stakes decisions are required.

Background Many theories of gambling harm propose that interactive design features of sports-betting platforms confer risk of harm by enabling cyclical patterns of repeated gambling engagement. This exploratory study investigated whether such features were used more frequently by people at higher risk of gambling harm relative to a demographically matched lower-risk control group. Methods This study used a case-control design to compare a group of 85 people at higher risk of gambling harm (PGSI 5+) with an age- and gender-matched control group at lower risk of harm (n = 84, PGSI 0-4). We compared the frequency with which groups self-reported using in-play betting, instant cash-out, multi and micro bets, social betting, and viewing live-streamed events within a betting app. Results The higher-risk group reported more frequent use of in-play betting and instant cash-out and were more likely to report streaming live sporting events within a betting app. Higher-risk participants were also more likely to make an immediate deposit to qualify for a marketing offer, and both groups reported being more likely to make risky bets when using bonus funds. We observed no group differences in the frequency of use of multis, micro-bets, or social betting. Conclusions Our findings were broadly consistent with the theory that design features of modern betting platforms contribute to gambling harm by facilitating continuous engagement. A notable finding was that in-app streaming of live events was more common among people at higher risk of gambling harm, consistent with a novel prediction made by the motivating theory.

Introduction: People place larger bets on risky events when they can cash-out before the bet concludes. This study experimentally investigates how cash-out availability impacts wider betting behaviour in a simulated betting task and whether risk of gambling problems moderates observed effects. Method: An incentivised, between-participants online experiment (n=377; 70.8% males, 28.6% females; Mage = 39.9), where participants could place bets on horse races via a simulated bookmaker’s website. Participants were randomly assigned to either have the option of cashing-out their bets or not. We examined choices to engage with the gambling task, stake sizes and implied win probabilities of placed bets, and measured risk of gambling problems by administering the PGSI. Results: The cash-out group was more likely to choose the gambling task over a distractor game (χ²(1, N=377)=4.59, p=0.032) and engaged with the gambling task for longer than the no-cash-out group (β=0.61, SE=0.23, p=0.0077). The cash-out group also made larger bets (W=19761.5, p=0.021), though this finding was more nuanced. There was no effect of cash-out availability on the average odds of placed bets (W=10635.5, p=0.67). No significant interactions between cash-out availability and PGSI were observed for either the implied win probability of placed bets (β<0.01, SE<0.01, p=0.44) or stake size (β=-0.02, SE=0.02, p=0.15), though a subgroup analysis revealed groupwise differences in stake size within a low-PGSI (W=6909.5, p=0.0076, n=260) subgroup. No such difference was found in the high-PGSI subgroup (W=1699.5, p=0.89, n=117). Conclusion: The provision of cash-out options in betting products results in significant changes in betting behaviour, which could potentially lead to increased risk of gambling harms.

Recent research has suggested that the availability of non-instrumental information about the outcome of a risky choice increases risk appetite. In this study, we aimed to perform a conceptual replication of these findings and to examine the cognitive mechanisms underlying this effect. Across two experiments (N = 150, 102), we presented participants with mathematically fair gambles and allowed them to choose the size of their bet. Between trials, we varied the presence of non-instrumental information that would reveal the outcome ahead of time. In both experiments, we did not find consistent evidence for an effect of the availability of non-instrumental information on bet size. These findings suggest that the previously reported effects of non-instrumental information on risk appetite may have been an idiosyncratic feature of experimental design, rather than a more general phenomenon that characterises human decision making under risk.

Disturbances of emotion are a core feature of psychological disorders generally and mood and anxiety disorders in particular. However, it remains unclear what specific patterns of affective disturbance are shared across different symptom domains. Here, we examined correlations between emotional-disorder symptom severity (anxiety, depression, hypomania, and anhedonia) and affective reactivity to gain and loss outcomes in a decision-making task with embedded sampling of emotional valence (Experiment 1: N = 329; preregistered replication in Experiment 2: N = 524). Using hierarchical Bayesian computational modeling of emotion self-reports, we found that greater affective reactivity to gains and losses in the task was associated with more-severe symptoms of both anxiety and hypomania. This suggests that heightened reactivity to both appetitive and aversive outcomes indexes emotional-disorder severity across multiple symptom domains of psychopathology, in line with theoretical frameworks that conceptualize affective disturbance as a generalized risk factor for psychopathology.

Model-free (MF) and model-based (MB) learning strategies are complementary decision-making processes used in evaluating choices with potential rewards. Disorders involving compulsive behaviours (e.g., substance use, gambling) are suggested to emerge from an overreliance on MF learning, though the reasons for this bias remain unclear. Sleep disruptions, common in these disorders, could be a contributing factor, however no study has examined the impact of sleep and/or sleep loss on an individual's engagement of each strategy. Thus, this study examined the influence of sleep on MF/MB learning in healthy adults. Participants (n = 67, Mage = 26.21yrs, SD = 5.82yrs, females = 65.67%) completed a two-stage reinforcement learning paradigm following a week of either sleep restriction (5-hr time in bed/night) or well-rested sleep (9-hr/night). Using mixed-effect logistic regressions and comprehensive computational modelling, we found no differences in MF and MB learning based on sleep condition (all p = > 0.05). However, regressions showed less REM sleep was associated with increased use of MB learning, whilst greater levels of REM sleep were associated with increased use of MF learning. Computational modelling supported this, revealing negative associations between the MB parameter estimate and REM sleep percentage (τ = -0.22, p = 0.02). This suggests the amount of REM sleep prior to learning may potentially play a role in determining which strategy will dominate. In particular, individuals with less REM sleep may be less willing or able to assess the relative costs and benefits of each strategy. Future research should explore this relationship further.

Introduction:The purpose of this investigation was to characterize the physical and physiological profile of elite military divers. Methods:The profile included anthropometric (height, weight, fat free mass, fat mass, percent body fat), performance testing ( V ˙ o 2max, 3-mile run (4.82 km), 0.5-mile swim (0.8 km), weighted pull-ups, estimated 1-rep max for bench and deadlift, and broad jump) and physiological functioning via the awake response (cortisol, testosterone, and dehydroepiandrosterone). Results:Anthropometric and performance results presented as MEAN ± SE include: age: 28.0 ± 0.5 years; height: 70.7 ± 0.3 in (179.6 ± 0.8 cm); weight: 193.3 ± 2.0 lbs (87.9 ± 0.9 kg); body fat percentage: 18.2% ± 0.6%; V ˙ o 2max: 55.3 ± 0.7 ml kg -1 · min-1; bench-press 1RM: 278.7 ± 7.7 lbs (126.8 ± 3.5 kg); deadlift 1RM: 397.9 ± 10.6 lbs (172.7 ± 4.8 kg). Significant associations were found between anthropometric measures and measures of magnitude in testosterone and DHEA. Physical performance metrics showed significant associations with summary parameters in all salivary hormones, with quartile splits yielding significant differences in absolute DHEA and 1RM deadlift (F (3, 30) = 2.97, p = 0.048), AUCg testosterone and broad jump (F (3, 37) = 2.86, p = 0.05), and AUCg T:C ratio and 25lb weighted pull ups (F (3, 35) = 4.66, p = 0.008). Linear mixed models revealed a significant effects of evolution/collection time point on AUCg DHEA at time points three (B = -2735.96, t (177.32) = -2.39, p = 0.018) and four (B = -3089.92, t (178.97) = -2.7, p = 0.008); and on peak testosterone at time point five (B = 28.12, t (215.4) = 2.4, p = 0.017) with reference to time point one. Conclusion:The data presented herein indicate there are certain periods of training that elicit significant changes in testosterone and DHEA while cortisol remains stable throughout the training cycle. To our knowledge, this effort is the first to document changes in stress biomarkers over time in elite military divers.

A common feature of contemporary sports-betting apps is ‘instant cash-out’, which allows users to settle a bet early in exchange for a discounted immediate payout. Despite high prevalence and links with gambling-related harm, relatively little is known about how personality traits associated with gambling, such as impulsivity, predict instant cash-out usage. To address this question, we recruited 145 general-population adult participants (69 men, 66 women, 10 non-binary or undisclosed; Mage = 36.3, SD = 10.7) to complete five self-report questionnaires related to impulsivity, as well as the Problem Gambling Severity Index (PGSI), and a validated cognitive task measuring individual differences in cash-out frequency. We then assessed how cash-out frequency in the behavioral task was associated with both self-reported impulsivity and PGSI. We found that cash-out frequency was negatively correlated both with PGSI scores and with a number of impulsivity-related traits including Dysfunctional Impulsivity, Lack of Premeditation, Positive Urgency, Sensation Seeking, and Fun Seeking. An exploratory factor analysis revealed that higher scores on a latent ‘Dysfunctional Impulsivity’ factor were negatively associated with cash-out frequency overall, whereas higher scores on an ‘Inhibition and Inflexibility’ factor predicted higher cash-out frequency specifically for bets with a low win probability. Taken together, results suggest that instant cash-out may primarily appeal to less impulsive people and those with lower PGSI scores. This raises the possibility that instant cash-out may specifically facilitate increased gambling behaviors among people with less prior experience of gambling.

Background and aims:Emotion dysregulation has been suggested to play a role in gambling-related harm, but past gambling research has typically assessed emotion dysregulation via self-report surveys rather than in a gambling context. Here, we sought to investigate how the severity of participants' hazardous gambling behavior was associated with their emotional reactivity and choice behavior within a simulated slot-machine task. Methods:Participants (N = 100) recruited via Prolific completed a behavioral task involving repeated choices between two simulated slot-machines. When chosen, slot-machines could produce one of five outcome types (win/near-win/neutral/near-loss/loss). After each outcome, participants reported their subjective emotional valence. Emotion data were analysed using a beta-autoregressive computational model, allowing us to extract per-participant estimates of trial-by-trial emotional reactivity to different slot-machine outcomes. Results:Correlation analyses revealed that people who engaged in more hazardous gambling behavior (higher PGSI scores) showed greater emotional reactivity to all slot-machine outcome types (all Spearman ρ > |0.31|, all p < 0.01, corrected for multiple comparisons). There were no significant associations between patterns of choice behavior and PGSI scores. Discussion and conclusions:Within a simulated slot-machine task, individuals who engaged in more hazardous gambling behavior showed greater emotional reactivity in general (more positive emotional reactions to wins and more negative emotional reactions to unpleasant events such as losses and near-wins). These results are consistent with a model in which emotion dysregulation is a risk factor for gambling-related harm, and serve to validate this model in a more naturalistic setting.

The impact of sleep loss on decision-making is well-documented, yet current quantitative methods often obscure the cognitive mechanisms underlying these impairments. This review examines evidence from key studies on how sleep deprivation affects decision-making domains, including risk propensity, effort and delay discounting, Bayesian reasoning, and cognitive flexibility. We critique the prevalent reliance on global behavioural metrics, highlighting three key limitations: 1) sleep-driven cognitive effects may be masked despite non-significant behavioural outcomes, 2) alternative cognitive strategies are often overlooked, and 3) these metrics fail to incorporate advances in cognitive neuroscience. To address these issues, we advocate for integrating computational cognitive models with existing quantitative methods. These models provide precise estimates of latent cognitive processes often missed by conventional analyses. As an exemplar, we reanalyse previously published data, revealing sleep-related deficits in value sensitivity and increased decision noise. These insights highlight the utility of computational cognitive models in supplementing traditional methods to uncover how sleep loss affects specific cognitive processes essential for decision-making. Beyond improving mechanistic insights, computational cognitive models may enhance the accuracy and interpretability of sleep research and inform the development of targeted interventions to mitigate decision-making impairments caused by sleep loss.

A common feature of contemporary sports-betting apps is ‘instant cash-out’, which allows users to settle a bet early in exchange for a discounted immediate payout. Despite high prevalence and links with gambling-related harm, relatively little is known about how personality traits associated with gambling, such as impulsivity, predict instant cash-out usage. To address this question, we recruited 145 general-population adult participants (69 men, 66 women, 10 non-binary or undisclosed; Mage = 36.3, SD = 10.7; participants resided in Australia, Canada, Ireland, New Zealand, the UK, or the USA) to complete five self-report questionnaires related to impulsivity, as well as the Problem Gambling Severity Index (PGSI), and a validated cognitive task measuring individual differences in cash-out frequency. We then assessed how cash-out frequency in the behavioral task was associated with both self-reported impulsivity and PGSI. We found that cash-out frequency was negatively correlated both with PGSI scores and with a number of impulsivity-related traits including Dysfunctional Impulsivity, Lack of Premeditation, Positive Urgency, Sensation Seeking, and Fun Seeking. An exploratory factor analysis revealed that higher scores on a latent ‘Dysfunctional Impulsivity’ factor were negatively associated with cash-out frequency overall, whereas higher scores on an ‘Inhibition and Inflexibility’ factor predicted higher cash-out frequency specifically for bets with a low win probability. Taken together, results suggest that instant cash-out may primarily appeal to less impulsive people and those with lower PGSI scores. This raises the possibility that instant cash-out may specifically facilitate increased gambling behaviors among people with less prior experience of gambling.

The valence of an individual's emotional response to an event is often thought to depend on their prior expectations for the event: better-than-expected outcomes produce positive affect and worse-than-expected outcomes produce negative affect. In recent years, this hypothesis has been instantiated within influential computational models of subjective affect that assume the valence of affect is driven by reward prediction errors. However, there remain a number of open questions regarding this association. In this project, we investigated the moderating effects of outcome valence and decision context (Experiment 1: free vs. forced choices; Experiment 2: trials with versus trials without counterfactual feedback) on the effects of reward prediction errors on subjective affect. We conducted two online experiments (N = 300 in total) of general-population samples recruited via Prolific to complete a risky decision-making task with embedded high-resolution sampling of subjective affect. Hierarchical Bayesian computational modelling revealed that both outcome amount and reward prediction errors influenced subjective affect, but that the effects of reward prediction errors were moderated by both outcome valence and decision context. Specifically, we found evidence that only negative reward prediction errors (worse-than-expected outcomes) influenced subjective affect, with no significant effect of positive reward prediction errors (better-than-expected outcomes). Moreover, these effects were only apparent on trials in which participants made a choice freely (but not on forced-choice trials) and when counterfactual feedback was absent (but not when counterfactual feedback was present). These results deepen our understanding of the effects of reward prediction errors on subjective affect.

When learning about stimuli comprised of multiple cues, humans and other animals tend to form stronger cue-outcome associations for more salient cues than for less salient cues. This phenomenon, termed overshadowing, has typically been demonstrated between cues that vary in salience because of differences in physical intensity. In this study, we investigated whether differences in the emotional valence of cues in a compound stimulus similarly led to differences in the strength of cue-outcome learning. Using a probabilistic categorisation task in which stimuli were compounds consisting of pairs of emotional or non-emotional cue images, we found consistent evidence for emotional overshadowing across both an initial exploratory study (N = 50) and a confirmatory preregistered replication study (N = 200). Specifically, both pleasant and unpleasant cue images tended to overshadow neutral cue images, but pleasant and unpleasant cue images did not overshadow one another. Moreover, across stimuli the magnitude of differences in learning between cues was proportional to differences in their absolute emotional valence, suggesting that attentional capture by both positively and negatively valenced emotions drives overshadowing. These findings have implications for understanding associative learning in natural environments, where stimuli are frequently imbued with emotional valence prior to learning.

After a risky choice, decision makers must frequently wait out a delay period before the outcome of their choice becomes known. In contemporary sports-betting apps, decision makers can "cash out" of their bet during this delay period by accepting a discounted immediate payout. An important open question is how availability of a postchoice cash-out option alters choice. We investigated this question using a novel gambling task that incorporated a cash-out option during the delay between bet and outcome. Across two experiments (N = 240 adults, recruited via Prolific), cash-out availability increased participants' bet amounts by up to 35%. Participants who were more likely to cash out when odds deteriorated were less likely to cash out when odds improved. Furthermore, the effect of cash-out availability on bet amounts was positively correlated with individual differences in cash-out propensity for bets with deteriorating odds only. These results suggest that cash-out availability may promote larger bets by allowing bettors to avoid losing their entire stake.

The literature on emotion and risk-taking is large and heterogeneous. Whereas some studies have found that positive emotions increase risk-taking and negative emotions increase risk aversion, others have found just the opposite. In this study, we investigated this question in the context of a risky decision-making task with embedded high-resolution sampling of participants' subjective emotional valence. Across two large-scale experiments (N = 329 and 524), we consistently found evidence for a negative association between self-reported emotional valence and risk-taking behaviors. That is, more negative subjective affect was associated with increased risk-seeking, and more positive subjective affect was associated with increased risk aversion. This effect was evident both when we compared participants with different levels of mean emotional valence as well as when we considered within-participant emotional fluctuations over the course of the task. Prospect-theoretic computational modeling analyses suggested that both between- and within-participant effects were driven by an effect of emotional valence on the curvature of the subjective utility function (i.e., increased risk tolerance in more negative emotional states), as well as by an effect of within-person emotion fluctuations on loss aversion. We interpret findings in terms of a tendency for participants in negative emotional states to choose high-risk, high-reward options in an attempt to improve their emotional state.

The detrimental effects of sleep loss on overall decision-making have been well described. Due to the complex nature of decisions, there remains a need for studies to identify specific mechanisms of decision-making vulnerable to sleep loss. Bayesian perspectives of decision-making posit judgement formation during decision-making occurs via a process of integrating knowledge gleaned from past experiences (priors) with new information from current observations (likelihoods). We investigated the effects of sleep loss on the ability to integrate multiple sources of information during decision-making by reporting results from two experiments: the first implementing both sleep restriction (SR) and total sleep deprivation (TSD) protocols, and the second implementing an SR protocol. In both experiments, participants were administered the Bayes Decisions Task on which optimal performance requires the integration of Bayesian prior and likelihood information. Participants in Experiment 1 showed reduced reliance on both information sources after SR, while no significant change was observed after TSD. Participants in Experiment 2 showed reduced reliance on likelihood after SR, especially during morning testing sessions. No accuracy-related impairments resulting from SR and TSD were observed in both experiments. Our findings show SR affects decision-making through altering the way individuals integrate available sources of information. Additionally, the ability to integrate information during SR may be influenced by time of day. Broadly, our findings carry implications for working professionals who are required to make high-stakes decisions on the job, yet consistently receive insufficient sleep due to work schedule demands.

As life expectancy following lung transplantation (LT) improves, vulnerability to glucocorticoid-induced osteoporotic fractures is increased. Our institution offers LT recipients protocolized anti-resorptive therapy, with zoledronic acid (ZA) used first line. Adults who underwent LT from January 2012 to December 2018 and survived at least 6 months were retrospectively studied. Co-primary outcomes were incidence, prevalence and predictors of osteoporotic fractures and major osteoporotic fractures post-LT. 405 LT recipients (41% female, median age 59 years) had median follow up of 4.9 years (Interquartile range (IQR) 3.4-6.7). Osteoporotic fracture prevalence was 12% (n=49) pre-LT and 15% (n=60) post-LT. Major osteoporotic fracture post-LT occurred in 11% (n=45). Antiresorptive therapy was received by 47% pre- and 89% post-LT. On multivariate analysis, risk factors for osteoporotic fracture were pre-LT osteoporotic fracture (Hazard ratio (HR) 2.32 (95% confidence interval (CI) 1.09-4.96)), female sex (HR 2.08 (95% CI 1.09-3.94)), glucocorticoid use pre-LT (HR 2.08 (95% CI 1.09-3.99)), and time (months) to first ZA infusion post-LT (HR 1.04 (95% CI 1.01-1.06)). Risk factors for major osteoporotic fracture were pre-LT osteoporotic fracture, female sex, age and time to first ZA infusion. LT recipients receiving protocolized anti-resorptive treatment post-LT had a low incidence of osteoporotic fracture. Data availability statement Ethics approval for this project does not extend to sharing of data for this study. Specific data requests should be made to the corresponding author.

To analyze retinal signs of synaptic injury in an animal model of inflammatory demyelination and neurodegeneration, i.e., EAE; to evaluate quantified assessment of a retinal layer with major synaptic component for predicting relentlessly progressive disability in MS; and to use a proteome-wide analysis of a deeply characterized MS population to explore the possibility of developing a serum-based biomarker that can quantify global synaptic injury.

Military personnel routinely complete stressful training exercises in harsh environmental conditions to prepare for intense operational demands. Purpose: This study determined the effect of environmental conditions on salivary hormone profiles in Marines during a mountain warfare training exercise (MTX). Methods: Two cohorts of Marines (age 22 ± 4, height 174 ± 7 cm, body mass 79.2 ± 11.5 kg) completed an MTX (elevation 2100 to 3500 m) in the Fall (n = 63, temperature 11 ± 2 °C) and Winter (n = 64, temperature −5 ± 4 °C). Saliva samples were provided before (PRE), during (MID), and after (POST) the MTX, and were assayed for α-amylase, cortisol, DHEA, testosterone, and osteocalcin. Results: Linear mixed models were used to determine significant interactions (time × season) and found differences in DHEA, testosterone, and osteocalcin. Testosterone and DHEA were lower at MID compared to PRE and POST during the Fall MTX. Testosterone was higher at MID compared to PRE and POST during the Winter MTX, while DHEA remained stable. Osteocalcin was higher in Fall participants compared to Winter but demonstrated a similar trend to increase at MID and decrease at POST in both groups. Cortisol was higher during the Winter MTX compared to the Fall. Conclusions: These findings highlight the differential physiological stress responses in varying seasonal conditions, suggesting the need for tailored training strategies to enhance military readiness and prevent hormonal dysregulation. Further research is needed to elucidate the mechanisms underlying these seasonal effects.

BACKGROUND: During periods of high-volume vigorous exercise, United States Marine Corps recruits often experience musculoskeletal injuries. While the program of instruction (POI) for basic training is a defined training volume, the total workload of boot camp, including movements around the base, is unknown. OBJECTIVE: The present study aimed to quantify the daily total workload, energy expenditure, and sleep during basic recruit training at Marine Corps Recruit Depot (MCRD) San Diego. METHODS: Eighty-four male recruits from MCRD San Diego wore wrist wearable physiological monitors to capture their complete workload (mileage from steps), energy expenditure, and sleep throughout the 10-week boot camp. RESULTS: Marine recruits traveled an average of 11.5±3.4 miles per day (M±SD), expended 4105±823 kcal per day, and slept an average of 5 : 48±1 : 06 hours and minutes per night. While the POI designates a total of 46.3 miles of running and hiking, the actual daily average miles yielded approximately 657.6±107.2 miles over the 10-week boot camp. CONCLUSION: Recruit training requires high physical demand and time under tension due to the cumulative volume of movements around base in addition to the POI planned physical training.