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Regular physical activity is deemed beneficial to physical, cognitive, and emotional health. Walking may be an accessible means of meeting physical activity recommendations and improving cognition. However, exercise effects on cognition are often explored at shorter durations (30 min or less), with fewer studies exploring how cognition is impacted during longer bouts of exercise. 36 (7 women) civilians and active-duty soldiers completed a VO 2 max test and two one-hour walks, one at and one below the ventilatory threshold (VT), on separate days. They completed the Go/No-Go and Task-Switching Tasks before, every 15 min during, and immediately after exercise, while wearing a near-infrared spectroscopy (NIRS) system to monitor prefrontal cortex (PFC) activity. Response speed during the Go/No-Go task was improved at VT compared to sub-VT at the expense of task accuracy. FP cortex was deactivated during exercise in the Task-Switching Task, potentially due to the increased competition for resources between the frontal cortex and movement related areas. As a result, exercise at or below VT may improve or impair cognitive performance and activation in executive function-related areas depending on the task type and exercise intensity level., (Published by Elsevier Inc.)

Stress carries diverse implications for perceptual, cognitive, and affective functions. One population particularly susceptible to acute stress-induced cognitive changes are individuals with high-stress jobs (e.g., military personnel). These individuals are often tasked with maintaining peak cognitive performance, including memory, spatial navigation, and decision-making under threatening and uncertain conditions. Previous research has separately examined decision-making under conditions of stress or uncertainty (i.e., ambiguous discrimination between friends and foes). However, questions remain about how operationally relevant stress impacts memory encoding and recall, or spatial learning, as well as how uncertainty may impact decision-making during stress. To address this gap, we examined the influence of a military-relevant emotional stressor on a series of cognitive tasks including recognition memory task (RMT), spatial orienting task (SOT), and shoot/don't shoot decision making (DMT). To examine the effects of uncertainty and stress we varied the stimulus clarity in the DMT. We utilized threat of shock (TOS) as a high-stakes outcome for decision errors. TOS increased sympathetic arousal but did not affect subjective emotional or HPA responses. TOS influenced decision times and confidence ratings in the DMT, but not response sensitivity or response bias. DMT performance varied by stimulus clarity (uncertainty) but did not differ between stress conditions. TOS did not influence recognition memory or spatial orienting. In sum, high levels of stress and uncertainty characterize military operations, yet stress experienced in military contexts can be difficult to induce in laboratory settings. We discuss several avenues for future research, including methodological considerations to better assess the magnitude and specificity of emotional stress-induction techniques in Soldiers., Competing Interests: The authors have declared that no competing interests exist., (Copyright: This is an open access article, free of all copyright, and may be freely reproduced, distributed, transmitted, modified, built upon, or otherwise used by anyone for any lawful purpose. The work is made available under the Creative Commons CC0 public domain dedication.)

Introduction: Personnel performance under stress hinges on various factors, including individual traits, training, context, mental and physiological states, and task demands. This study explored the link between the traits of military personnel and their performance outcomes in five domains: move, shoot, communicate, navigate, and sustain., Methods: A total of 387 U.S. Army soldiers participated in this study, undergoing trait assessments covering physical, cognitive, social-emotional, demographic/lifestyle, and health domains. Performance was measured through lab and field events assessing a broad range of individual and team-level skills under conditions demanding resilience to acute cognitive and physical stress exposure. Analysis used feature selection and elastic net regression., Results: Analyses revealed complex associations between traits and performance, with physical, cognitive, health-related, social-emotional, and lifestyle traits playing roles in guiding and constraining performance. Measures of resilience, emotion regulation, grit, and mindfulness were identified as relevant predictors of several performance-related outcomes., Discussion: Results carry implications for the selection, training, and operational effectiveness of personnel in high-stakes occupations including military and first response. Further research is necessary to explore the mechanisms underlying these associations and inform targeted interventions to boost personnel effectiveness., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. The author(s) declared that they were an editorial board member of Frontiers, at the time of submission. This had no impact on the peer review process and the final decision., (Copyright © 2024 Brunyé, Goring, Cantelon, Eddy, Elkin-Frankston, Elmore, Giles, Hancock, Masud, McIntyre, McKenzie, Mitchell, O’Donovan, Racicot and Ramsay.)

Stress occurs when conditions burden or exceed an individual's adaptive resources. Military personnel are often tasked with maintaining peak performance under such stressful conditions. Importantly, the effects of stress are nuanced and may vary as a function of individual traits and states. Recent interdisciplinary research has sought to model and identify such relationships. In two previously reported efforts, Soldiers first completed a comprehensive battery of trait assessments across four general domains thought to be predictive of performance: cognitive, health, physical, and social-emotional, and then completed the Decision-Making under Uncertainty and Stress (DeMUS) virtual reality task that probed spatial cognition, memory, and decision-making under stress and variable uncertainty. The present analysis explores whether cognitive, health, physical, and social-emotional trait assessments, as well as physiological state measures, predict or modulate DeMUS performance outcomes under stress. Multiple regression analyses examined the effect of each trait predictor and stress responsiveness on quantitative task performance outcomes. Results revealed that one measure of state stress reactivity, salivary cortisol, predicted lower recognition memory sensitivity. Further, trait measures of healthy eating, agility, flexibility, cognitive updating, and positive emotion predicted enhanced spatial orienting and decision-making performance and confidence. Together, the results suggest that select individual states and traits may predict cognition under stress. Future research should expand to ecologically relevant military stressors during training and operations.

Introduction: Personnel engaged in high-stakes occupations, such as military personnel, law enforcement, and emergency first responders, must sustain performance through a range of environmental stressors. To maximize the effectiveness of military personnel, an a priori understanding of traits can help predict their physical and cognitive performance under stress and adversity. This work developed and assessed a suite of measures that have the potential to predict performance during operational scenarios. These measures were designed to characterize four specific trait-based domains: cognitive, health, physical, and social-emotional., Materials and Methods: One hundred and ninety-one active duty U.S. Army soldiers completed interleaved questionnaire-based, seated task-based, and physical task-based measures over a period of 3-5 days. Redundancy analysis, dimensionality reduction, and network analyses revealed several patterns of interest., Results: First, unique variable analysis revealed a minimally redundant battery of instruments. Second, principal component analysis showed that metrics tended to cluster together in three to five components within each domain. Finally, analyses of cross-domain associations using network analysis illustrated that cognitive, health, physical, and social-emotional domains showed strong construct solidarity., Conclusions: The present battery of metrics presents a fieldable toolkit that may be used to predict operational performance that can be clustered into separate components or used independently. It will aid predictive algorithm development aimed to identify critical predictors of individual military personnel and small-unit performance outcomes., (Published by Oxford University Press on behalf of the Association of Military Surgeons of the United States 2023. This work is written by (a) US Government employee(s) and is in the public domain in the US.)

The ability to regulate the intake of unhealthy foods is critical in modern, calorie dense food environments. Frontal areas of the brain, such as the dorsolateral prefrontal cortex (DLPFC), are thought to play a central role in cognitive control and emotional regulation. Therefore, increasing activity in the DLPFC may enhance these functions which could improve the ability to reappraise and resist consuming highly palatable but unhealthy foods. One technique for modifying brain activity is transcranial direct current stimulation (tDCS), a non-invasive technique for modulating neuronal excitability that can influence performance on a range of cognitive tasks. We tested whether anodal tDCS targeting the right DLPFC would influence how people perceived highly palatable foods. In the present study, 98 participants were randomly assigned to receive a single session of active tDCS (2.0 mA) or sham stimulation. While receiving active or sham stimulation, participants viewed images of highly palatable foods and reported how pleasant it would be to eat each food (liking) and how strong their urge was to eat each food (wanting). We found that participants who received active versus sham tDCS stimulation perceived food as less pleasant, but there was no difference in how strong their urge was to eat the foods. Our findings suggest that modulating excitability in the DLPFC influences "liking" but not "wanting" of highly palatable foods. Non-invasive brain stimulation might be a useful technique for influencing the hedonic experience of eating but more work is needed to understand when and how it influences food cravings., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2023 The Authors.)

Introduction: Regular aerobic exercise benefits psychological health, enhancing mood in clinical and nonclinical populations. However, single bouts of exercise exert both positive and negative effects on emotion. Exercise reliably increases emotional arousal. Its effects on emotional valence are thought to depend on an interplay between cognitive and interoceptive factors that change as a function of exercise intensity, as studied in clinical, healthy, and athlete populations. However, special populations, such as military, first responders, and endurance athletes, have unique physical exertion requirements that can coincide with additional cognitive, physical, and environmental stressors not typical of the general population. Load carriage is one such activity. The present study examined emotional valence and arousal during sustained, heavy load carriage akin to military training and operations., Methods: Thirteen (one woman) active duty soldiers completed a V̇O2max test, a 2-h loaded (up to 50% body mass) and unloaded (empty rucksack) treadmill foot march (3 mph/4% incline) on separate days, during which they rated their exertion and emotional valence and arousal every 40 min. They also completed measures of positive and negative affect and anxiety before and every 20 min after the foot march., Results: Two hours of loaded foot march led to elevated perceived exertion and less positive, more negative and anxious feelings. Higher rated exertion and more negative emotion were associated with higher percent HRmax and V̇O2peak at multiple time points., Conclusions: These results support affect exertion models such as the Dual Mode Theory, whereby physical exertion becomes less pleasant with increasing intensity, and provide insights into how affective responses applied contexts may help predict time to fatigue or failure., (Copyright © 2022 Written work prepared by employees of the Federal Government as part of their official duties is, under the U.S. Copyright Act, a “work of the United States Government” for which copyright protection under Title 17 of the United States Code is not available. As such, copyright does not extend to the contributions of employees of the Federal Government.)

A growing body of work has investigated the effects of acute, or single bouts of, aerobic exercise on cognitive function. However, review of this research has largely focused on changes following exercise, with less focus on cognitive changes during exercise. The purpose of this review is to discuss the critical characteristics of this literature to date, including: (1) what has been done, (2) what has been found, and (3) what is next. Furthermore, previous meta-analytic reviews have demonstrated there is a small positive effect on cognition when measured during exercise, with executive functions showing the largest effects. However, these reviews group executive functions together. Here we explore how inhibition, working memory and cognitive flexibility are individually impacted by factors such as exercise intensity or duration. Searches of electronic databases and reference lists from relevant studies resulted in 73 studies meeting inclusion criteria. Studies were grouped by executive and non-executive cognitive domains, intensity and duration of exercise bouts. Within the executive domain, we found that effects on working memory and cognitive flexibility remain mixed, effects on inhibition are clearer. Moderate intensity exercise improves response time, vigorous intensity impairs accuracy. Moderate to vigorous intensity improves response time across non-executive domains of attention, motor speed and information processing, with no significant effects on accuracy. Memory processes are consistently improved during exercise. Effects of exercise duration on response time and accuracy are nuanced and vary by cognitive domain. Studies typically explore durations of 45 min or less, extended exercise durations remain largely unexplored. We highlight factors to consider when assessing exercise-cognition relationships, as well as current gaps and future directions for work in this field., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Cantelon and Giles.)

Wearable technologies for measuring digital and chemical physiology are pervading the consumer market and hold potential to reliably classify states of relevance to human performance including stress, sleep deprivation, and physical exertion. The ability to efficiently and accurately classify physiological states based on wearable devices is improving. However, the inherent variability of human behavior within and across individuals makes it challenging to predict how identified states influence human performance outcomes of relevance to military operations and other high-stakes domains. We describe a computational modeling approach to address this challenge, seeking to translate user states obtained from a variety of sources including wearable devices into relevant and actionable insights across the cognitive and physical domains. Three status predictors were considered: stress level, sleep status, and extent of physical exertion; these independent variables were used to predict three human performance outcomes: reaction time, executive function, and perceptuo-motor control. The approach provides a complete, conditional probabilistic model of the performance variables given the status predictors. Construction of the model leverages diverse raw data sources to estimate marginal probability density functions for each of six independent and dependent variables of interest using parametric modeling and maximum likelihood estimation. The joint distributions among variables were optimized using an adaptive LASSO approach based on the strength and directionality of conditional relationships (effect sizes) derived from meta-analyses of extant research. The model optimization process converged on solutions that maintain the integrity of the original marginal distributions and the directionality and robustness of conditional relationships. The modeling framework described provides a flexible and extensible solution for human performance prediction, affording efficient expansion with additional independent and dependent variables of interest, ingestion of new raw data, and extension to two- and three-way interactions among independent variables. Continuing work includes model expansion to multiple independent and dependent variables, real-time model stimulation by wearable devices, individualized and small-group prediction, and laboratory and field validation., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Brunyé, Yau, Okano, Elliott, Olenich, Giles, Navarro, Elkin-Frankston, Young and Miller.)

Emotional eating is defined as an increase in eating following negative emotion. Self-reported emotional eating has been associated with physical health concerns. However, experimental and daily diary studies indicate that induced or naturally experienced negative emotions do not reliably lead to increased eating behavior in people without eating disorders, not even among self-professed emotional eaters. Emotional eating may depend on associations people have made between specific emotions and eating. We describe a set of studies with the overarching goal of determining whether accounting for the variation in people's associations between eating and different discrete emotions is the key to observing emotional eating. In both Study 1 (N = 118) and 2 (N = 111), we asked people to report on their tendency to eat following sadness and anxiety and determined how much they ate when induced to feel sad or anxious in the lab (Study 1) or experiencing these emotions in daily life (Study 2). We found no support for our hypotheses in either study; self-professed sad- or anxious-eaters did not eat more when induced to experience these emotions in the lab, or when experiencing these emotions in daily life. Thus, accounting for the variation in people's associations between eating and two discrete emotions, sadness and anxiety, is not the key to observing sad or anxious eating behavior in the lab or in daily life. Preregistration, materials, data, and code: https://osf.io/kcqej/ (Study 1) and https://osf.io/3euvg/ (Study 2)., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Emotional states are thought to influence athletic performance. Emotions characterized by high arousal enhance exercise performance. Extant research has focused on the valence and arousal dimensions of emotions, but not whether the motivational dimension (the extent to which the emotion engenders approach or avoidance behaviors) influences exercise performance. Two studies aimed to determine whether films and music chosen to induce approach- (i.e., anger), avoidance- (i.e., fear), and neutral-oriented emotions would successfully induce their intended emotional states (Study 1) and whether anger and fear emotion inductions would influence 2-mile time trial performance (Study 2). In Study 1, the films and music successfully induced their intended emotions. In Study 2, run time and perceived level of exertion did not differ between emotions across all participants or among faster running participants per a median split. However, among slower running participants, the anger induction increased the 2-mile running speed relative to the neutral induction. These findings suggest that emotions eliciting approach-related motivational states may improve exercise performance, particularly in slower runners., (Copyright © 2020 Giles, Horner, Anderson, Elliott and Brunyé.)

The probiotic industry continues to grow in both usage and the diversity of products available. Scientific evidence supports clinical use of some probiotic strains for certain gastrointestinal indications. Although much less is known about the impact of probiotics in healthy populations, there is increasing consumer and scientific interest in using probiotics to promote physical and psychological health and performance. Military men and women are a unique healthy population that must maintain physical and psychological health in order to ensure mission success. In this narrative review, we examine the evidence regarding probiotics and candidate probiotics for physical and/or cognitive benefits in healthy adults within the context of potential applications for military personnel. The reviewed evidence suggests potential for certain strains to induce biophysiological changes that may offer physical and/or cognitive health and performance benefits in military populations. However, many knowledge gaps exist, effects on health and performance are generally not widespread among the strains examined, and beneficial findings are generally limited to single studies with small sample sizes. Multiple studies with the same strains and using similar endpoints are needed before definitive recommendations for use can be made. We conclude that, at present, there is not compelling scientific evidence to support the use of any particular probiotic(s) to promote physical or psychological performance in healthy military personnel. However, plausibility for physical and psychological health and performance benefits remains, and additional research is warranted. In particular, research in military cohorts would aid in assessing the value of probiotics for supporting physical and psychological health and performance under the unique demands required of these populations., (Copyright © 2020 Agans, Giles, Goodson, Karl, Leyh, Mumy, Racicot and Soares.)

Introduction: Physical exertion has both beneficial and detrimental effects on cognitive performance, particularly cognitive control. Research into physical exertion under conditions of load carriage is particularly important given that military personnel and first responders must perform optimally under such combinatorial physical stressors. The present work sought to characterize cognitive control as a function of physical exertion and load carriage in a military operational scenario., Methods: Thirty-one active-duty soldiers underwent a 4-h operationally relevant and fatiguing scenario that included two 1-h foot marches under load carriage conditions of 8.8, 47.2, 50.7 kg on each of three separate days. During each foot march, they completed five 5-min blocks of an auditory go/no-go task of response inhibition., Results: Results showed that response inhibition declined with increasing load carriage and physical exertion, as evidenced by lower proportion of correct responses, higher proportion of false alarms, and lower response sensitivity between all three load conditions, particularly upon successive foot marches and time blocks within each foot march., Conclusions: The results support previous laboratory-based work on load carriage and physical exertion and suggest that deteriorations in cognitive control witnessed in laboratory settings are more pronounced within realistic operational scenarios akin to those encountered by military personnel and first responders.

Objective: Caffeine and dietary supplement (DS) use by college students is not well-documented. Given reported associations between energy drink consumption and sensation seeking, we used the Sensation Seeking Scale Form V (SSS-V) to assess relationships between sensation-seeking, caffeine, and DS use. Participants: Data from 1,248 college students from five US institutions were collected from 2009 to 2011. Methods: Linear regression was used to examine relationships between scores on the SSS-V and caffeine and DS use, demographic, and lifestyle characteristics. Results: Male sex, nonHispanic race-ethnicity, higher family income, tobacco use, consuming caffeinated beverages, more than 400 mg caffeine per day, and energy drinks with alcohol at least 50% of the time, were significantly associated with higher total SSS-V scores ( P  < 0.001). Those using protein DSs had higher total, disinhibition, and boredom susceptibility SSS-V scores ( P s < 0.001). Conclusions: Results demonstrate a positive correlation between sensation-seeking attitudes and habitual caffeine, energy drink, and DS consumption.

Individuals with stressful occupations, such as law enforcement and military personnel, are required to operate in high stakes environments that can be simultaneously physically and emotionally demanding. These individuals are tasked with maintaining peak performance under stressful and often unpredictable conditions, exerting high levels of cognitive control to sustain attention and suppress task-irrelevant actions. Previous research has shown that physical and emotional stressors differentially influence such cognitive control processes. For example, physical stress impairs while emotional stress facilitates the ability to inhibit a prepotent response, yet, interactions between the two remain poorly understood. Here we examined whether emotional stress induced by threat of unpredictable electric shock mitigates the effects of physical stress on response inhibition. Participants performed an auditory Go/NoGo task under safe versus threat conditions while cycling at high intensity (84% HRmax) for 50 min. In threat conditions, participants were told they would receive mild electric shocks that were unpredictable and unrelated to task performance. Self-reported anxiety increased under threat versus safe conditions, and perceived exertion increased with exercise duration. As predicted, we observed decrements in response inhibition (increased false alarms) as exertion increased under safe conditions, but improved response inhibition as exertion increased under threat conditions. These findings are consistent with previous work showing that anxiety induced by unpredictable threat promotes adaptive survival mechanisms, such as improved vigilance, threat detection, cautious behavior, and harm avoidance. Here, we suggest that emotional stress induced by unpredictable threat can also mitigate decrements in cognitive performance experienced under physically demanding conditions. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Military personnel and emergency responders perform cognitively-demanding tasks during periods of sustained physical exertion and limited caloric intake. Cognitive function is preserved during short-term caloric restriction, but it is unclear if preservation extends to combined caloric restriction and physical exertion. According to the "reticular-activating hypofrontality" model, vigorous exertion impairs prefrontal cortex activity and associated functions. This double-blind, placebo-controlled, crossover study examined cognitive function during sustained exertion while volunteers were calorically-deprived. Twenty-three volunteers were calorie-depleted for two days on one occasion and fully-fed on another. They completed intermittent bouts of exercise at 40-65% VO 2peak while prefrontal cortex-dependent tasks of cognitive control, mood, and perceived exertion were assessed. Calorie deprivation impaired accuracy on the task-switching task of set-shifting (p < .01) and decreased sensitivity on the go/no-go task of response inhibition (p < .05). Calorie deprivation did not affect risk taking on the Rogers risk task. During exercise, calorie deprivation, particularly on day 2, increased perceived exertion (p < .05) and impaired mood states of tension, depression, anger, vigor, fatigue, and confusion (all p < .01). Physical exertion during severe calorie deprivation impairs cognitive control, mood, and self-rated exertion. Reallocation of cerebral metabolic resources from the prefrontal cortex to structures supporting movement may explain these deficits., (Published by Elsevier Inc.)

Background & Aims: Caffeine intake in a convenience sample of U.S. college students (N = 1248) was surveyed at five geographically-dispersed United States (U.S.) universities., Methods: Intake from coffee, tea, soft drinks, energy drinks, gums, and medications was assessed. Associations between caffeine intake and demographic variables including sex, age, race/ethnicity, family income, general health, exercise, weight variables and tobacco use were examined. Reasons for use of caffeine-containing products were assessed., Results: Caffeine, in any form, was consumed by 92% of students in the past year. Mean daily caffeine consumption for all students, including non-consumers, was 159 mg/d with a mean intake of 173 mg/d among caffeine users. Coffee was the main source of caffeine intake in male (120 mg/d) and female (111 mg/d) consumers. Male and female students consumed 53 vs. 30 mg/d of caffeine in energy drinks, respectively, and 28% consumed energy drinks with alcohol on at least one occasion. Students provided multiple reasons for caffeine use including: to feel awake (79%); enjoy the taste (68%); the social aspects of consumption (39%); improve concentration (31%); increase physical energy (27%); improve mood (18%); and alleviate stress (9%)., Conclusions: As in the general U.S. population, coffee is the primary source of caffeine intake among the college students surveyed. Energy drinks provide less than half of total daily caffeine intake but more than among the general population. Students, especially women, consume somewhat more caffeine than the general population of individuals aged 19-30 y but less than individuals aged 31-50 y., (Published by Elsevier Ltd.)

Acute exercise consistently benefits both emotion and cognition, particularly cognitive control. We evaluated acute endurance exercise influences on emotion, domain-general cognitive control and the cognitive control of emotion, specifically cognitive reappraisal. Thirty-six endurance runners, defined as running at least 30 miles per week with one weekly run of at least 9 miles (21 female, age 18-30 years) participated. In a repeated measures design, participants walked at 57% age-adjusted maximum heart rate (HR max ; range 51%-63%) and ran at 70% HR max (range 64%-76%) for 90 min on two separate days. Participants completed measures of emotional state and the Stroop test of domain-general cognitive control before, every 30 min during and 30 min after exercise. Participants also completed a cognitive reappraisal task (CRT) after exercise. Functional near-infrared spectroscopy (fNIRS) tracked changes in oxygenated and deoxygenated hemoglobin (O 2 Hb and dHb) levels in the prefrontal cortex (PFC). Results suggest that even at relatively moderate intensities, endurance athletes benefit emotionally from running both during and after exercise and task-related PFC oxygenation reductions do not appear to hinder prefrontal-dependent cognitive control.

Food intake and exercise have been shown to alter body satisfaction in a state-dependent manner. One-time consumption of food perceived as unhealthy can be detrimental to body satisfaction, whereas an acute bout of moderate-intensity aerobic exercise can be beneficial. The current study examined the effect of exercise on state body image and appearance-related self-esteem following consumption of isocaloric foods perceived as healthy or unhealthy in 36 female college students (18-30 years old) in the Northeastern United States. Using a randomized-controlled design, participants attended six study sessions with breakfast conditions (healthy, unhealthy, no food) and activity (exercise, quiet rest) as within-participants factors. Body image questionnaires were completed prior to breakfast condition, between breakfast and activity conditions, and following activity condition. Results showed that consumption of an unhealthy breakfast decreased appearance self-esteem and increased body size perception, whereas consumption of a healthy breakfast did not influence appearance self-esteem but increased body size perception. Exercise did not influence state body image attitudes or perceptions following meal consumption. Study findings suggest that morning meal type, but not aerobic exercise, influence body satisfaction in college-aged females., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Glucose intake has been found to improve some aspects of cognitive performance; however, results are often inconsistent. This inconsistency may be related to expectations surrounding glucose, which can have strong effects on performance outcomes. The present study evaluated the independent and interactive effects of acute sugar intake, in the form of high-fructose corn syrup (HFCS), and sugar expectancies on cognitive performance and mood. One hundred five healthy young adults were randomized according to sugar intake and expectation: consumed-sugar/told-sugar, consumed-sugar/told-no-sugar, consumed-no-sugar/told-sugar, and consumed-no-sugar/told-no-sugar. Thirty minutes after sugar or no-sugar intake, participants completed the Profile of Mood States and a battery of cognitive tests, including immediate and delayed recall, the Stroop test, n-back task, and continuous performance task. Tension increased following the expectation of consuming sugar, regardless of sugar consumption (p < .05). On the continuous performance task, accuracy and sensitivity were higher (ps < .05) and false alarm rate was lower (p < .05) following sugar than no sugar intake. No effects of sugar intake or expectation were found for any other mood or cognitive measure (ps > .05). The findings suggest that sugar intake in the form of HFCS may benefit certain cognitive processes, such as those that require sustained attention, but that the expectation of sugar intake is not sufficient to produce such benefits. (PsycINFO Database Record, ((c) 2018 APA, all rights reserved).)

Caffeine reliably increases emotional arousal, but it is unclear whether and how it influences other dimensions of emotion such as emotional valence. These experiments documented whether caffeine influences emotion and emotion regulation choice and success. Low to abstinent caffeine consumers (maximum 100 mg/day) completed measures of state anxiety, positive and negative emotion, and salivary cortisol before, 45 min after, and 75 min after consuming 400 mg caffeine or placebo. Participants also completed an emotion regulation choice task, in which they chose to employ cognitive reappraisal or distraction in response to high and low intensity negative pictures (Experiment 1), or a cognitive reappraisal task, in which they employed cognitive reappraisal or no emotion regulation strategy in response to negative and neutral pictures (Experiment 2). State anxiety, negative emotion, and salivary cortisol were heightened both 45 and 75 min after caffeine intake relative to placebo. In Experiment 1, caffeine did not influence the frequency with which participants chose reappraisal or distraction, but reduced negativity of the picture ratings. In Experiment 2, caffeine did not influence cognitive reappraisal success. Thus, caffeine mitigated emotional responses to negative situations, but not how participants chose to regulate such responses or the success with which they did so.

Habitual exercise is associated with enhanced domain-general cognitive control, such as inhibitory control, selective attention, and working memory, all of which rely on the frontal cortex. However, whether regular exercise is associated with more specific aspects of cognitive control, such as the cognitive control of emotion, remains relatively unexplored. The present study employed a correlational design to determine whether level of habitual exercise was related to performance on the Stroop test measuring selective attention and response inhibition, the cognitive reappraisal task measuring cognitive reappraisal success, and associated changes in prefrontal cortex (PFC) oxygenation using functional near-infrared spectroscopy. 74 individuals (24 men, 50 women, age 18-32 years) participated. Higher habitual physical activity was associated with lower Stroop interference (indicating greater inhibitory control) and enhanced cognitive reappraisal success. Higher habitual exercise was also associated with lower oxygenated hemoglobin (O 2 Hb) in the PFC in response to emotional information. However, NIRS data indicated that exercise was not associated with cognitive control-associated O 2 Hb in the PFC. Behaviorally, the findings support and extend the previous findings that habitual exercise relates to more successful cognitive control of neutral information and cognitive reappraisal of emotional information. Future research should explore whether habitual exercise exerts causal benefits to cognitive control and PFC oxygenation, as well as isolate specific cognitive control processes sensitive to change through habitual exercise.

Tea is perceived as more relaxing than coffee, even though both contain caffeine. L-theanine in tea may account for the difference. Consumed together, caffeine and theanine exert similar cognitive effects to that of caffeine alone, but exert opposite effects on arousal, in that caffeine accentuates and theanine mitigates physiological and felt stress responses. We evaluated whether caffeine and theanine influenced cognition under emotional arousal. Using a double-blind, repeated-measures design, 36 participants received 4 treatments (200 mg caffeine + 0 mg theanine, 0 mg caffeine + 200 mg theanine, 200 mg caffeine + 200 mg theanine, 0 mg caffeine + 0 mg theanine) on separate days. Emotional arousal was induced by highly arousing negative film clips and pictures. Mood, salivary cortisol, and visual attention were evaluated. Caffeine accentuated global processing of visual attention on the hierarchical shape task (p < 0.05), theanine accentuated local processing (p < 0.05), and the combination did not differ from placebo. Caffeine reduced flanker conflict difference scores on the Attention Network Test (p < 0.05), theanine increased difference scores (p < 0.05), and the combination did not differ from placebo. Thus, under emotional arousal, caffeine and theanine exert opposite effects on certain attentional processes, but when consumed together, they counteract the effects of each other.

Readers differentially adopt an agent's perspective as a function of pronouns encountered during reading. The present study assessed the reliability of this effect across narrative contexts and self-reported variation in levels of engagement during reading. Experiment 1 used an extended sample (N = 263) and replicated an interactive influence of pronouns on perspectives adopted during reading simple action sentences (e.g., You are peeling the cucumber.), with You promoting an agent's perspective, and He promoting an onlooker's external perspective. The magnitude of this effect was partially accounted for by individual differences in the tendency to get actively engaged during reading. Specifically, readers who self-reported greater empathic engagement during reading also showed a higher likelihood to adopt an agent's perspective when sentences used the pronoun You or I. Experiment 2 (N = 217) examined whether these influences of pronouns and individual differences would emerge with relatively realistic, extended narratives; effects were generally less robust than with single sentence scenarios, though empathic engagement still predicted adopting an agent's perspective with the pronoun You or I. Furthermore, even in the absence of perspective modulation in response to pronouns, comprehension was maintained. These results demonstrate that differentially adopting perspectives as a function of pronouns is not universal or necessary for comprehension, but rather influenced by narrative context and individuals' propensity to find themselves immersed in described events. Results are considered within the framework of embodied cognition, representational pluralism, individual differences, and high-powered replication projects. (PsycINFO Database Record, ((c) 2016 APA, all rights reserved).)

Omega-3 fatty acid (n-3 PUFA) intake is associated with improved mood and cognition, but randomized controlled trials addressing the causal nature of such relationships are less clear, especially in healthy, young adults. Stress is one potential mechanism by which n-3 PUFAs may influence mood. Thus the present aim is to evaluate the influence of n-3 PUFA supplementation on stress-induced changes to mood, cognition, and physiological stress markers in healthy, young adults. Using a double-blind, placebo-controlled design, 72 young adults were randomized to receive 2800mg/day fish oil (n=36, 23 females) or olive oil control (n=36, 22 females) for 35days. Subjects completed measures of mood and cognition before supplementation, and two times after supplementation: following an acute stressor or non-stressful control task. The stress induction was effective in that the stressor impaired mood, including augmenting feelings of tension, anger, confusion and anxiety, reduced accuracy on a cognitive task measuring attentional control and the ability to regulate emotion, and increased salivary cortisol and pro-inflammatory cytokine interleukin-1β (IL-1β). Rated anger and confusion increased with stress in the olive oil group, but remained stable in the fish oil group. However, fish oil had no further effects on mood, cognitive function, cortisol, or IL-1β. Fish oil exerted few effects in stressful and non-stressful situations, consistent with findings showing little influence of n-3 PUFA supplementation on mood and cognition in young, healthy individuals. Potential target populations who would more likely benefit from increased n-3 PUFA intake are discussed., (Published by Elsevier Inc.)

Extensive experimental psychology research has attempted to parse the complex relationship between psychosocial stress, mood, cognitive performance, and physiological changes. To do so, it is necessary to have effective, validated methods to experimentally induce psychosocial stress. The Trier Social Stress Test (TSST) is the most commonly used method of experimentally inducing psychosocial stress, but it is resource intensive. Less resource intense psychosocial stress tasks include the Socially Evaluative Cold Pressor Task (SECPT) and a computerized mental arithmetic task (MAT). These tasks effectively produce a physiological and psychological stress response and have the benefits of requiring fewer experimenters and affording data collection from multiple participants simultaneously. The objective of this study was to compare the magnitude and duration of these three experimental psychosocial stress induction paradigms. On each of four separate days, participants completed either a control non-stressful task or one of the three experimental stressors: the TSST, SECPT, or MAT. We measured mood, working memory performance, salivary cortisol and alpha-amylase (AA), and heart rate. The TSST and SECPT exerted the most robust effects on mood and physiological measures. TSST effects were generally evident immediately post-stress as well as 10- and 20-minutes after stress cessation, whereas SECPT effects were generally limited to the duration of the stressor. The stress duration is a key determinant when planning a study that utilizes an experimental stressor, as researchers may be interested in collecting dependent measures prior to stress cessation. In this way, the TSST would allow the investigator a longer window to administer tasks of interest.

Both acute and chronic exercise is consistently associated with a number of benefits to physical and mental health, including cardiovascular function, body weight, mood, and cognition. Near-infrared spectroscopy is an ideal method to measure changes in oxygenated and deoxygenated hemoglobin (O2Hb and dHb) levels in the prefrontal cortex (PFC) during exercise, to better understand the locus of such changes in affective and cognitive processes. The present study tracked time-dependent changes in O2Hb and dHb levels in the PFC as a function of parametrically manipulated target exercise intensity. Near-infrared spectroscopy was conducted as regular exercisers completed a 30-min bout of exercise with one of three target intensities: 52% (low condition), 68% (moderate condition), or 84% (high condition) of age-adjusted maximum heart rate. Heart rate data confirmed that the participants reached their goal intensities immediately, after 10 min, or after 20 min, respectively. Data showed that O2Hb and dHb levels in the PFC increased as a function of both exercise load and duration. An 84%>68%>52% difference was evident after 18 min of cycling for O2Hb and after 23 min of cycling for dHb. The present results add to the growing body of literature showing that at submaximal levels, increasing exercise intensities reliably promote prefrontal cerebral oxygenation.

Depression is one of the most prevalent disorders in the United States, and rates of depression are higher for women than men. Despite their widespread use, drugs used in the treatment of depression are only moderately more effective than placebo in treating the disorder. Effective treatment of perinatal depression is of particular concern as treatment can influence both the mother and the developing child. Omega-3 polyunsaturated fatty acid (n-3 PUFA) supplementation may reduce symptoms of major depressive disorder and perinatal depression. The aim of the present review was to evaluate epidemiological studies examining PUFA intake and depressive symptoms in the general population, as well as double-blind, placebo-controlled trials assessing the influence of n-3 PUFA in healthy individuals and those with depression; specific consideration was given to perinatal depression and potential gender differences in the relationship. Although there is some evidence to suggest that n-3 PUFA intake is associated with reduced depressive symptoms, particularly in females, these results are generally limited to epidemiological studies, whereas results from randomized controlled trials are mixed., (© 2013 International Life Sciences Institute.)

Information processing is generally biased toward global cues, often at the expense of local information. Equivocal extant data suggests that arousal states may accentuate either a local or global processing bias, at least partially dependent on the nature of the manipulation, task, and stimuli. To further differentiate the conditions responsible for such equivocal results we varied caffeine doses to alter physiological arousal states and measured their effect on tasks requiring the retrieval of local versus global spatial knowledge. In a double-blind, repeated-measures design, non-habitual (Experiment 1; N = 36, M = 42.5 ± 28.7 mg/day caffeine) and habitual (Experiment 2; N = 34, M = 579.5 ± 311.5 mg/day caffeine) caffeine consumers completed four test sessions corresponding to each of four caffeine doses (0, 100, 200, 400 mg). During each test session, participants consumed a capsule containing one of the three doses of caffeine or placebo, waited 60 min, and then completed two spatial tasks, one involving memorizing maps and one spatial descriptions. A spatial statement verification task tested local versus global spatial knowledge by differentially probing memory for proximal versus distal landmark relationships. On the map learning task, results indicated that caffeine enhanced memory for distal (i.e., global) compared to proximal (i.e., local) comparisons at 100 (marginal), 200, and 400 mg caffeine in non-habitual consumers, and marginally beginning at 200 mg caffeine in habitual consumers. On the spatial descriptions task, caffeine enhanced memory for distal compared to proximal comparisons beginning at 100 mg in non-habitual but not habitual consumers. We thus provide evidence that caffeine-induced physiological arousal amplifies global spatial processing biases, and these effects are at least partially driven by habitual caffeine consumption.

Energy drinks containing caffeine, taurine, and glucose may improve mood and cognitive performance. However, there are no studies assessing the individual and interactive effects of these ingredients. We evaluated the effects of caffeine, taurine, and glucose alone and in combination on cognitive performance and mood in 24-hour caffeine-abstained habitual caffeine consumers. Using a randomized, double-blind, mixed design, 48 habitual caffeine consumers (18 male, 30 female) who were 24-hour caffeine deprived received one of four treatments (200 mg caffeine/0 mg taurine, 0 mg caffeine/2000 mg taurine, 200 mg caffeine/2000 mg taurine, 0 mg caffeine/0 mg taurine), on each of four separate days, separated by a 3-day wash-out period. Between-participants treatment was a glucose drink (50 g glucose, placebo). Salivary cortisol, mood and heart rate were measured. An attention task was administered 30-minutes post-treatment, followed by a working memory and reaction time task 60-minutes post-treatment. Caffeine enhanced executive control and working memory, and reduced simple and choice reaction time. Taurine increased choice reaction time but reduced reaction time in the working memory tasks. Glucose alone slowed choice reaction time. Glucose in combination with caffeine, enhanced object working memory and in combination with taurine, enhanced orienting attention. Limited glucose effects may reflect low task difficulty relative to subjects' cognitive ability. Caffeine reduced feelings of fatigue and increased tension and vigor. Taurine reversed the effects of caffeine on vigor and caffeine-withdrawal symptoms. No effects were found for salivary cortisol or heart rate. Caffeine, not taurine or glucose, is likely responsible for reported changes in cognitive performance following consumption of energy drinks, especially in caffeine-withdrawn habitual caffeine consumers., (Copyright © 2012 Elsevier Inc. All rights reserved.)

Recent work suggests that a dose of 200-400 mg caffeine can enhance both vigilance and the executive control of visual attention in individuals with low caffeine consumption profiles. The present study seeks to determine whether individuals with relatively high caffeine consumption profiles would show similar advantages. To this end, we examined the effects of four caffeine doses (0 mg, 100 mg, 200 mg, 400 mg) on low- and high-level visual attention in individuals with high consumption profiles (n=36), in a double-blind study using a repeated measures design. Results from the Attention Network Test indicated that caffeine enhanced both vigilance and the executive control of visual attention, but only at the highest administered dose (400 mg). We demonstrate that in habitual consumers high doses of caffeine can produce beneficial changes in visual attention. These results carry implications for the theorized interactions between caffeine, adenosine and dopamine in brain regions mediating visual attention., (Published by Elsevier Inc.)

A computational simulation of the oxidation of chemical species inside a metal emitter electrospray ion source, in the context of electrospray mass spectrometry (ES-MS), has been developed. The analysis code employs a boundary integral method for the solution of the Laplace equation for the electric potential and current and incorporates standard activation and concentration polarization functions for the redox-active species in the system to define the boundary conditions. This paper provides a demonstration of the capability of this simulation method. Due to the approximate nature of some of the input data, and certain simplifying assumptions, the present results must be considered semiquantitative. The specific system modeled consisted of a 100-μm-i.d., inert metal capillary ES emitter and a spray solution composed of an analyte dissolved in CH(3)CN/H(2)O (90/10 v/v). Variable parameters included the concentration (i.e., 5.0, 10, 20, and 50 μM) of the easily oxidized analyte ferrocene (Fc, dicyclopentadienyl iron) in the solution, and solution conductivities of 1.9, 3.8, and 7.6 × 10(-)(7) Ω(-)(1)/cm, with an operational flow rate of 5.0 μL/min and ES currents on the order of 0.05 μA. Under these defined conditions, the two most prominent reactions at the emitter metal/solution interface were assumed to be H(2)O oxidation (2H(2)O = O(2) + 4H(+) + 4e(-)) and ferrocene oxidation (Fc = Fc(+) + e(-)). Using this model, it was possible to predict the interfacial potentials, as well as the current density for each of the reactions, as a function of axial position from the emitter spray tip back upstream, under the various operational conditions. The simulations show that the majority of the current from the redox reactions is generated within a 200-300-μm region near the spray tip. The lower the value of E(0) for a specific reaction, the further upstream from the tip the reaction extends.