Search

This article explores the history of the little-known polygamy exclusion in the 1891 Immigration Act. Tracing the development of this polygamy restriction in the late nineteenth century, the article shows how anxieties about the European migration of Mormon converts shaped immigration legislation, which was then almost immediately redirected to regulate the migration of Turkish immigrants by the early 1900s. Racialized as “American Mohammedans,” Mormons came to embody a foreign, “uncivilized,” and semi-imperial threat for many nineteenth-century Americans. As the persecution of Mormons receded in the 1890s, however, the increasing visibility of Muslim immigrants from the Ottoman Empire fed new fears about religious difference, racial inferiority, and sexual and marital deviance. US immigration officials addressed such concerns by attempting to apply the polygamy exclusion on Turkish immigrants, but soon found themselves at the center of diplomatic tensions between US and Ottoman officials. Analyzing the imperial negotiations at play as US immigration law ran up against the power of the Ottoman Empire, the article brings deeper attention to the ways in which the policing of polygamy and “proper” marital formations were ultimately shaped by anxieties over race, religion, and empire.

ObjectivePoor sleep is a modifiable risk factor for multiple disorders. Frontline treatments (e.g. cognitive-behavioral therapy for insomnia) have limitations, prompting a search for alternative approaches. Here, we compare manualized Mindfulness-Based Therapy for Insomnia (MBTI) with a Sleep Hygiene, Education, and Exercise Program (SHEEP) in improving subjective and objective sleep outcomes in older adults.MethodsWe conducted a single-site, parallel-arm trial, with blinded assessments collected at baseline, post-intervention and 6-months follow-up. We randomized 127 participants aged 50–80, with a Pittsburgh Sleep Quality Index (PSQI) score ⩾5, to either MBTI (n = 65) or SHEEP (n = 62), both 2 hr weekly group sessions lasting 8 weeks. Primary outcomes included PSQI and Insomnia Severity Index, and actigraphy- and polysomnography-measured sleep onset latency (SOL) and wake after sleep onset (WASO).ResultsIntention-to-treat analysis showed reductions in insomnia severity in both groups [MBTI: Cohen's effect size d = −1.27, 95% confidence interval (CI) −1.61 to −0.89; SHEEP: d = −0.69, 95% CI −0.96 to −0.43], with significantly greater improvement in MBTI. Sleep quality improved equivalently in both groups (MBTI: d = −1.19; SHEEP: d = −1.02). No significant interaction effects were observed in objective sleep measures. However, only MBTI had reduced WASOactigraphy (MBTI: d = −0.30; SHEEP: d = 0.02), SOLactigraphy (MBTI: d = −0.25; SHEEP: d = −0.09), and WASOPSG (MBTI: d = −0.26; SHEEP (d = −0.18). There was no change in SOLPSG. No participants withdrew because of adverse effects.ConclusionsMBTI is effective at improving subjective and objective sleep quality in older adults, and could be a valid alternative for persons who have failed or do not have access to standard frontline therapies.

Previous literature suggests that cross-frequency phase synchronization is a mechanism by which information is transmitted and coordinated in the brain. Since cross-frequency phase synchronization is only strictly possible when two oscillators form a harmonic frequency ratio (e.g., 2:1, 3:1), a recent theory posited that interactions between brain oscillations at different frequencies are facilitated/hindered by the transient occurrence of harmonic/non-harmonic cross-frequency arrangements. In this line, recent evidence has shown that 2:1 harmonic relationships between alpha (8–14 Hz) and theta (4–8 Hz) rhythms are reduced during meditative states in experienced practitioners. In the present study, we investigated whether mindfulness training in novices is associated with longitudinal changes in alpha-theta cross-frequency dynamics during meditation practice. Thirty-six participants (mean age = 30.3; 2 men) underwent an 8-week mindfulness training program based on the mindfulness-based stress reduction (MBSR) syllabus and electroencephalography (EEG) recordings (64 electrodes) were performed during a guided meditation before and after the training. Mindfulness training compliance (quantified by minutes of attendance and practice at home) was significantly correlated to decreased 3:1 harmonicity and cross-frequency phase synchrony between alpha and theta rhythms during meditation. Mindfulness training in novices was shown to be associated with a reduction in alpha-theta cross-frequency coupling during meditation. EEG parameters based on alpha-theta cross-frequency dynamics may be adequate for quantifying and/or facilitating mindfulness meditation training.

Study Objectives We attempted to predict vigilance performance in adolescents during partial sleep deprivation using task summary metrics and drift diffusion modelling measures (DDM) derived from baseline vigilance performance. Methods In the Need for Sleep studies, 57 adolescents (age = 15–19 years) underwent two baseline nights of 9-h time-in-bed (TIB), followed by two cycles of weekday sleep-restricted nights (5-h or 6.5-h TIB) and weekend recovery nights (9-h TIB). Vigilance was assessed daily with the Psychomotor Vigilance Task (PVT), with the number of lapses (response times ≥ 500 ms) as the primary outcome measure. The two DDM predictors were drift rate, which quantifies the speed of information accumulation and determines how quickly an individual derives a decision response, and non-decision time range, which indicates within-subject variation in physical, non-cognitive responding, e.g. motor actions. Results In the first week of sleep curtailment, faster accumulation of lapses was significantly associated with more lapses at baseline (p = .02), but not the two baseline DDM metrics: drift and non-decision time range (p > .07). On the other hand, faster accumulation of lapses and greater increment in reaction time variability from the first to the second week of sleep restriction were associated with lower drift (p < .007) at baseline. Conclusions Among adolescents, baseline PVT lapses can predict inter-individual differences in vigilance vulnerability during 1 week of sleep restriction on weekdays, while drift more consistently predicts vulnerability during more weeks of sleep curtailment. Clinical Trial Information Effects of Napping in Sleep-Restricted Adolescents, clinicaltrials.gov, NCT02838095. The Cognitive and Metabolic Effects of Sleep Restriction in Adolescents (NFS4), clinicaltrials.gov, NCT03333512.

End-of-life care may constitute a vast proportion of health care expenditure globally. In the US, one-quarter of all medicare spending goes towards healthcare for people near the end of life. This is especially true for cancer patients. Our study aimed to estimate hospital spending in cancer patients in the last six months of life. Patients with cancer who died between June 2015 to December 2016 (n=653) were extracted from Singapore’s electronic medical records. A two-part model was used to estimate hospitalization spending. In the last month of life, we found that 85% of the patients did not have chemotherapy, 43% had good quality care, and 31% had palliative care. The average total hospitalization spending in the last six months of life was S$59,180. Further analysis by month from death revealed that spending increased sharply by 62%, from $7,591 in the sixth month of life to $12,315 in the last month of life. Decedents who received chemotherapy in the last month of life spent $6,925 more on hospitalization expenditure than those who did not ($17,915 vs $10,990). Among decedents seen by a palliative doctor, hospital expenditures in the last month were $8,745 higher compared to those who did not ($16,119 vs $7,374). The study depicted the huge hospitalization spending during the end-of-life for cancer patients in Singapore. Expenditure on end-of-life care can be further reduced with investment in community-based services and integrated care across the community and acute sectors, where hospital-to-home services and earlier palliative care can provide potential cost-effective solutions.

Mindfulness-based training has shown potential in reducing anxious and ruminative thoughts before sleep, and improving sleep quality. A majority of experiments on this topic have studied Mindfulness-Based Stress Reduction, or related 8-week programs. In this study, we measured the effects of a 4-week Mindfulness Foundation course on sleep quality assessed via subjective report and actigraphic recording. Ninety-six participants were recruited from a pool of Mindfulness Foundation course attendees and studied in a waitlist-control design. Although sleep complaints were not an inclusion criterion for this study, sleep quality was poor in the sample as a whole at baseline. We found that sleep quality improved in both groups across the study period (ηp2 = 0.22), with no statistical difference between groups. In contrast, pre-sleep cognitive arousal was significantly reduced in the treatment, but not the waitlist group (ηp2 = 0.058). Exploratory analysis revealed that reductions in cognitive arousal were correlated with improvements in sleep quality in the treatment group, but not the waitlist group. In the actigraphy data, a small but statistically significant interaction favoring the treatment group was found in the amount of time spent awake during the night (i.e., wake after sleep onset) (ηp2 = 0.070). Overall, our data demonstrate that some of the benefits to sleep commonly seen over 8 weeks of mindfulness practice can also be observed over a shorter intervention period, and add to the growing body of evidence that mindfulness can help those with poor sleep quality.

Sleep deprivation (SD) consistently degrades performance in tasks requiring sustained attention, resulting in slower and more variable response times that worsen with time-on-task. Loss of motivation to exert effort may exacerbate performance degradation during SD. To test this, we evaluated sustained performance on a vigilance task, combining this with an effort-based decision-making task and pupillometry. Vigilance was tested at rest and after sleep deprivation, under different incentive conditions (1, 5 or 15 cents for fast responses). Subsequently, preference measures were collected from an effort-discounting task, in which a commensurate reward was offered for maintaining attentional performance for different durations (1, 5, 10, 20 or 30 min). Vigilance was impaired during SD, in a manner modulated by reward value. Preference metrics showed that the value of available rewards was discounted by task duration, an effect compounded by SD. Pupillometry revealed that arousal was modulated during SD in a value-based manner, and moment-to-moment fluctuations in pupil diameter were directly predictive of performance. Together, these data demonstrate that attentional performance can be interpreted within a value-based effort allocation framework, such that the perceived cost of attentional effort increases after sleep deprivation.

Background The COVID-19 pandemic has negatively impacted psychological health. Mindfulness training, which helps individuals attend to the present moment with a nonjudgmental attitude, improves sleep and reduces stress during regular times. Mindfulness training may also be relevant to the mitigation of harmful health consequences during acute crises. However, certain restrictions may necessitate the web-based delivery of mindfulness training (ie, rather than in-person group training settings). Objective The objective of our study was to examine the effects of mindfulness interventions during the COVID-19 pandemic and to evaluate the effectiveness of web-based interventions. Methods Data from an ongoing study were used for this retrospective equivalence analysis. Recruited participants were enrollees from mindfulness courses at a local charity organization that promoted mental wellness. This study had no exclusion criteria. We created three groups; two groups received their training during the COVID-19 pandemic (in-person training group: n=36; videoconferencing group: n=38), and a second control group included participants who were trained before the pandemic (n=86). Our primary outcomes were self-reported stress and sleep quality. Baseline levels and changes in these variables due to mindfulness training were compared among the groups via an analysis of covariance test and two one-tailed t tests. Results Baseline perceived stress (P=.50) and sleep quality (P=.22) did not differ significantly among the three groups. Mindfulness training significantly reduced stress in all three groups (P Conclusions Web-based mindfulness training via videoconferencing may be a useful intervention for reducing stress during times when traditional, in-person training is not feasible. However, it may not be useful for improving sleep quality.

BACKGROUND The COVID-19 pandemic has negatively impacted psychological health. Mindfulness training, which helps individuals attend to the present moment with a nonjudgmental attitude, improves sleep and reduces stress during regular times. Mindfulness training may also be relevant to the mitigation of harmful health consequences during acute crises. However, certain restrictions may necessitate the web-based delivery of mindfulness training (ie, rather than in-person group training settings). OBJECTIVE The objective of our study was to examine the effects of mindfulness interventions during the COVID-19 pandemic and to evaluate the effectiveness of web-based interventions. METHODS Data from an ongoing study were used for this retrospective equivalence analysis. Recruited participants were enrollees from mindfulness courses at a local charity organization that promoted mental wellness. This study had no exclusion criteria. We created three groups; two groups received their training during the COVID-19 pandemic (in-person training group: n=36; videoconferencing group: n=38), and a second control group included participants who were trained before the pandemic (n=86). Our primary outcomes were self-reported stress and sleep quality. Baseline levels and changes in these variables due to mindfulness training were compared among the groups via an analysis of covariance test and two one-tailed t tests. RESULTS Baseline perceived stress (P=.50) and sleep quality (P=.22) did not differ significantly among the three groups. Mindfulness training significantly reduced stress in all three groups (PP=.002). Sleep quality improved significantly in the prepandemic training group (PPP=.02), and participants in the videoconferencing group engaged in marginally more daily practice than the in-person training group. CONCLUSIONS Web-based mindfulness training via videoconferencing may be a useful intervention for reducing stress during times when traditional, in-person training is not feasible. However, it may not be useful for improving sleep quality.

We conducted a study to understand how dynamic functional brain connectivity contributes to the moderating effect of trait mindfulness on the stress response. 40 male participants provided subjective reports of stress, cortisol assays, and functional MRI before and after undergoing a social stressor. Self-reported trait mindfulness was also collected. Experiencing stress led to significant decreases in the prevalence of a connectivity state previously associated with mindfulness, but no changes in two connectivity states with prior links to arousal. Connectivity did not return to baseline 30 min after stress. Higher trait mindfulness was associated with attenuated affective and neuroendocrine stress response, and smaller decreases in the mindfulness-related connectivity state. In contrast, we found no association between affective response and functional connectivity. Taken together, these data allow us to construct a preliminary brain-behaviour model of how mindfulness dampens stress reactivity and demonstrate the utility of time-varying functional connectivity in understanding psychological state changes.

Despite calls for objective measures of mindfulness to be adopted in the field, such practices have not yet become established. Recently, a breath-counting task (BCT) was proposed as a reliable and valid candidate for such an instrument. In this study, we show that the psychometric properties of the BCT are reproducible in a sample of 127 Asian undergraduates. Specifically, accuracy on the BCT was associated with everyday lapses and sustained attention, and weakly associated with subjectively measured mindfulness. BCT metrics also showed good test-retest reliability. Extending the use of the paradigm, we further found that two different types of task errors-miscounts and resets-were correlated with different aspects of cognition. Miscounts, or errors made without awareness, were associated with attentional lapses, whereas resets, or self-caught errors, were associated with mind-wandering. The BCT may be a suitable candidate for the standardized measurement of mindfulness that could be used in addition to mindfulness questionnaires.

According to the recalibrational theory of anger, anger is a computationally complex cognitive system that evolved to bargain for better treatment. Anger coordinates facial expressions, vocal changes, verbal arguments, the withholding of benefits, the deployment of aggression, and a suite of other cognitive and physiological variables in the service of leveraging bargaining position into better outcomes. The prototypical trigger of anger is an indication that the offender places too little weight on the angry individual's welfare when making decisions, i.e. the offender has too low a welfare tradeoff ratio (WTR) toward the angry individual. Twenty-three experiments in six cultures, including a group of foragers in the Ecuadorian Amazon, tested six predictions about the computational structure of anger derived from the recalibrational theory. Subjects judged that anger would intensify when: (i) the cost was large, (ii) the benefit the offender received from imposing the cost was small, or (iii) the offender imposed the cost despite knowing that the angered individual was the person to be harmed. Additionally, anger-based arguments conformed to a conceptual grammar of anger, such that offenders were inclined to argue that they held a high WTR toward the victim, e.g., “the cost I imposed on you was small”, “the benefit I gained was large”, or “I didn't know it was you I was harming.” These results replicated across all six tested cultures: the US, Australia, Turkey, Romania, India, and Shuar hunter-horticulturalists in Ecuador. Results contradict key predictions about anger based on equity theory and social constructivism. © 2017 Elsevier B.V.

Efficient classification of mental workload, an important issue in neuroscience, is limited, so far to single task, while cross-task classification remains a challenge. Furthermore, network approaches have emerged as a promising direction for studying the complex organization of the brain, enabling easier interpretation of various mental states. In this paper, using two mental tasks (N-back and mental arithmetic), we present a framework for cross- as well as within-task workload discrimination by utilizing multiband electroencephalography (EEG) cortical brain connectivity. In detail, we constructed functional networks in EEG source space in different frequency bands and considering the individual functional connections as classification features, we identified salient feature subsets based on a sequential feature selection algorithm. These connectivity subsets were able to provide accuracy of 87% for cross-task, 88% for N-back task, and 86% for mental arithmetic task. In conclusion, our method achieved to detect a small number of discriminative interactions among brain areas, leading to high accuracy in both within-task and cross-task classifications. In addition, the identified functional connectivity features, the majority of which were detected in frontal areas in theta and beta frequency bands, helped delineate the shared as well as the distinct neural mechanisms of the two mental tasks.

Achievement-oriented adolescents often study long hours under conditions of chronic sleep restriction, adversely affecting cognitive function. Here, we studied how napping and rest breaks (interleaved off-task periods) might ameliorate the negative effects of sleep restriction on processing speed. Fifty-seven healthy adolescents (26 female, age = 15-19 years) participated in a 15-day live-in protocol. All participants underwent sleep restriction (5 h time-in-bed), but were then randomized into two groups: one of these groups received a daily 1-h nap opportunity. Data from seven of the study days (sleep restriction days 1-5, and recovery days 1-2) are reported here. The Blocked Symbol Decoding Test, administered once a day, was used to assess time-on-task effects and the effects of rest breaks on processing speed. Controlling for baseline differences, participants who took a nap demonstrated faster speed of processing and greater benefit across testing sessions from practice. These participants were also affected significantly less by time-on-task effects. In contrast, participants who did not receive a nap benefited more from the rest breaks that were permitted between blocks of the test. Our results indicate that napping partially reverses the detrimental effects of sleep restriction on processing speed. However, rest breaks have a greater effect as a countermeasure against poor performance when sleep pressure is higher. These data add to the growing body of evidence showing the importance of sleep for good cognitive functioning in adolescents, and suggest that more frequent rest breaks might be important in situations where sleep loss is unavoidable.

Introduction Mindfulness-based training has shown potential in reducing anxious and ruminative thoughts before sleep, and improving sleep quality. However, traditional 8-week programs have limited acceptability and uptake. In this study, we aimed to test the effects of a short introductory mindfulness training course on pre-sleep arousal and sleep quality. Methods Enrollees in a 4-week Mindfulness Foundation Course were invited to participate in the study and were allocated to one of two groups: intervention (N = 57) and waitlist control (N = 39). 101 participants enrolled in the experiment and 96 completed the protocol (mean(sd) age = 49.5(1.5), 56 female). Participants completed the Pittsburgh Sleep Quality Inventory (PSQI) and the pre-sleep arousal scale (PSAS), and were monitored by actigraphy for a week at baseline and post-intervention. To test the effect of the intervention, outcome variables were subjected to repeated-measures ANCOVA with group as a between-subject variable, and age, gender, and years of education as covariates using intent-to-treat analysis. Results PSQI scores improved across both groups (treatment: t56=4.25, p Conclusion The study suggests that a 4-week introductory mindfulness course has moderate effects on reducing cognitive arousal prior to sleep, and that these effects are correlated with improvements in subjective sleep quality. Support This study was funded from a STaR investigator grant (NMRC/STaR/0015/2013) and the National Research Foundation (Singapore) Science of Learning Grant (NRF2016-SOL002-001).

Introduction Dynamic functional connectivity (DFC) analysis of resting-state fMRI data has been successfully used to track fluctuations in arousal in the human brain. Changes in DFC have also been reported with acute sleep deprivation. Here, we demonstrate that dynamic connectivity states (DCS) previously related to arousal are reproducible, and are associated with individual differences in sustained attention declines after one night of total sleep deprivation. Methods 32 participants underwent two counterbalanced resting-state fMRI scans: during rested wakefulness (RW) and following total sleep deprivation (SD). They also completed the Psychomotor Vigilance Test (PVT), a sustained attention task that is highly sensitive to the effects of sleep loss. SD vulnerability was computed as the decrease in response speed (∆RS) and increase in lapses (∆lapse) in SD compared with RW. Dynamic functional connectivity analysis was conducted on rs-fMRI data. Connectivity matrices were clustered to obtain 5 prototypical DCS. We calculated the proportion of time participants spent in each of these DCS, as well as how often participants transitioned between DCSs. Relationships between SD vulnerability and connectivity metrics were then correlated. Results We recovered two DCS that were highly similar (ρ = .89-.91) to arousal-related DCS observed in previous work (high arousal state (HAS); low arousal state (LAS)). After sleep deprivation, the proportion of time spent in the LAS increased significantly (t29=3.16, p=.0039), while there was no significant change in HAS (t29=-1.43, p=.16). We observed significantly more state transitions in RW compared with SD. Change in LAS and HAS across sleep conditions correlated significantly with SD vulnerability (ΔLASxΔRS: r=-0.64, p Conclusion This study adds to the evidence that two specific reproducible DCS are robust markers of arousal and attention, and may be useful indicators of SD vulnerability. Support This work was supported by the National Medical Research Council, Singapore (STaR/0015/2013), and the National Research Foundation Science of Learning (NRF2016-SOL002-001).

Sustaining attention is highly demanding and can falter if there is a shift in willingness to exert effort. Motivated attentional performance and effort preference were tracked in relation to increasing time-on-task (Experiment 1) and sleep deprivation (Experiment 2). Performance decrement with time-on-task was attenuated with reward, while preference to deploy effort decreased with longer task duration. Sleep deprivation, accentuated performance decline with time-on-task, and was accompanied by greater effort-discounting. Motivated attention performance was associated with higher fronto-parietal activation, in both normal and sleep deprived conditions. However, after sleep deprivation modulation of activation by reward was reduced in the anterior cingulate cortex (ACC) and left anterior insula (aIns). Together, these results depict how motivational decline affects performance when one gets tired after sustained task performance and/or sleep deprivation.

Mind wandering at critical moments during a cognitive task degrades performance. At other moments, mind wandering could serve to conserve task-relevant resources, allowing a brief mental respite. Recent research has shown that, if target timing is predictable, mind wandering episodes coincide with moments of low target likelihood. Conversely, mind wandering can be avoided at moments when targets are expected. In the current study, we tested whether mind wandering can be guided by implicit temporal expectations when target timing is less predictable. In two experiments (Experiment 1: N = 37, Experiment 2: N = 61), participants performed a sustained attention task in which target events were preceded by a variable pre-target interval (foreperiod). As time passes over the foreperiod duration, implicit target expectation increases, given that it has not yet appeared. In Experiment 1, all foreperiod durations were equally probable (uniform distribution: 2-10 seconds). This resulted in faster responses when targets were preceded by long compared to short foreperiods (foreperiod-effect). In contrast, mind wandering, assessed by thought probes inserted following short or long foreperiods, did not follow this pattern. In Experiment 2, alterations in the foreperiod distribution (left or right-skewed) resulted in changes in the behavioral foreperiod-effect, but mind wandering was unaffected. Our findings indicate that implicit timing strongly affects behavioral response to target events, but has no bearing on the mind wandering. Contrastingly, mind wandering did correlate with performance deterioration due to fatigue (time-on-task), suggesting that the thought probe method was sufficiently sensitive to behaviorally relevant changes in mental state.

Robustly linking dynamic functional connectivity (DFC) states to behaviour is important for establishing the utility of the method as a functional measurement. We previously used a sliding window approach to identify two dynamic connectivity states (DCS) related to vigilance. A new sample of 32 healthy participants underwent two sets of task-free functional magnetic resonance imaging (fMRI) scans, once in a well-rested state and once after a single night of total sleep deprivation. Using a temporal difference method, DFC and clustering analysis on the task-free fMRI data revealed five centroids that were highly correlated with those found in previous work. In particular, two of these states were associated with high and low arousal respectively. Individual differences in vulnerability to sleep deprivation were measured by assessing state-related changes in Psychomotor Vigilance Test (PVT) performance. Changes in the duration spent in each of the arousal states from the well-rested to the sleep-deprived condition correlated with declines in PVT performance. The reproducibility of DFC measures and their association with vigilance highlight their utility in serving as a neuroimaging method with behavioural relevance. (178 words).

Robustly linking dynamic functional connectivity (DFC) states to behaviour is an important goal of the fledgling research using these methods. Here, we demonstrate in an independent dataset that two connectivity states previously linked to arousal and sustained attention are associated with individual differences in vulnerability to sleep deprivation. 32 healthy participants underwent two sets of resting-state functional magnetic resonance imaging (fMRI) scans, once in a well-rested state and once after a single night of total sleep deprivation. Individual differences in vulnerability to this manipulation were measured using changes in Psychomotor Vigilance Test (PVT) performance. DFC and clustering analysis on the resting state fMRI data revealed five centroids that were highly correlated with those found in previous work, including two states associated with high and low arousal. Changes in these arousal states from the well-rested to the sleep-deprived condition specifically were correlated with changes in PVT performance. Global signal was also correlated with this change in univariate analysis, but was not a significant incremental predictor in a multivariate model. Although head motion increased following sleep deprivation, this did not predict change in PVT performance. Our results provide good evidence of the reliability, validity, and reproducibility of DFC measures, particularly with regard to measuring arousal and attention.

In contrast to peer-assisted learning (PAL) in clinical training, there is scant literature on the efficacy of PAL during basic medical sciences teaching for preclinical students. A group of senior medical students aimed to design and deliver clinically oriented small-group tutorials after every module in the preclinical curriculum at a United Kingdom medical school. Twenty tutorials were delivered by senior students throughout the year to first- and second-year students. A baseline questionnaire was delivered to inform the development of the program followed by an end-point questionnaire the next year ( n = 122). Quizzes were administered before and after five separate tutorials to assess changes in mean student scores. Additionally, each tutorial was evaluated via a questionnaire for participants ( n = 949). All five posttutorial quizzes showed a significant improvement in mean student score ( P < 0.05). Questionnaires showed students found the program to be relevant and useful for revision purposes and appreciated how tutorials contextualized basic science to clinical medicine. Students appreciated the interactive nature of the sessions and found receiving personalized feedback about their learning and consolidating information with someone familiar with the material to be useful. With the inclusion of the program, students felt there were now an adequate number of tutorials during the year. In conclusion, this study shows that senior medical students can design and deliver a program that adds value to the mostly lecture-based formal preclinical curriculum. We hope that our study can prompt further work to explore the effect of PAL on the teaching of basic sciences during preclinical studies.

Rest breaks are commonly administered as a countermeasure to reduce on-the-job fatigue, both physical and mental. However, this practice makes the assumption that recovery from fatigue, as measured by the reversal of performance declines, is the sole effect of taking a break on behavior. Here, through administering rest breaks of differing lengths in between blocks of a mentally demanding symbol decoding task, we show that this assumption may not be strictly true. First, we replicate previous work by showing that taking a longer break leads to two correlated effects: greater immediate rebound in performance, and greater subsequent time-on-task decline. Using fMRI, we reveal that time-on-task in this paradigm is associated with increasing recruitment of fronto-parietal areas associated with top-down control, and decreasing deactivation in the default-mode network. Finally, by analyzing individual differences, we reveal a potential neural basis for our behavioral observation: greater recovery following long breaks is associated with greater activity in the putamen, an area associated with the automatic generation of motor responses, followed by greater activity in left middle frontal gyrus by the end of those task periods. Taken together, this suggests a shift in the implicit engagement of automatic and controlled attentional processing following longer breaks. This shift may be undesirable or detrimental in real-world situations where maintaining a stable level of attention over time is necessary.

Mind wandering at critical moments during a cognitive task degrades performance. At other moments, mind wandering could serve to conserve task-relevant resources, allowing a brief mental respite. Recent research has shown that, if target timing is predictable, mind wandering episodes coincide with moments of low target likelihood. Conversely, mind wandering can be avoided at moments when targets are expected. In the current study, we tested whether mind wandering can be guided by implicit temporal expectations when target timing is less predictable. In two experiments (Experiment 1: N = 37, Experiment 2: N = 61), participants performed a sustained attention task in which target events were preceded by a variable pre-target interval (foreperiod). As time passes over the foreperiod duration, implicit target expectation increases, given that it has not yet appeared. In Experiment 1, all foreperiod durations were equally probable (uniform distribution: 2–10 s). This resulted in faster responses when targets were preceded by long compared to short foreperiods (foreperiod-effect). In contrast, mind wandering, assessed by thought probes inserted following short or long foreperiods, did not follow this pattern. In Experiment 2, alterations in the foreperiod distribution (left or right-skewed) resulted in changes in the behavioral foreperiod-effect, but mind wandering was unaffected. Our findings indicate that implicit timing strongly affects behavioral response to target events, but has no bearing on the mind wandering. Contrastingly, mind wandering did correlate with performance deterioration due to fatigue (time-on-task), suggesting that the thought probe method was sufficiently sensitive to behaviorally relevant changes in mental state.

Introduction Poor sleep is a modifiable risk factor for multiple chronic disorders. Mindfulness-based therapies potentially improve sleep by enhancing awareness and acceptance of internal and external experiences, thus reducing pre-sleep hyper-arousal. In this pre-registered, randomized controlled trial, we tested the effect of mindfulness-based treatment for insomnia (MBTI) on subjective sleep quality measures (Pittsburgh Sleep Quality Questionnaire, PSQI) in the elderly. Methods Participants above 50 years old with sleep difficulties (PSQI ≥ 5) (mean (sd) age = 62.0 (6.35), 44 female) attended either an 8-week MBTI (N = 34) or sleep hygiene education and exercise program (SHEEP; N = 35). Before and after the interventions, we collected PSQI, insomnia symptoms and features measures (Pre-Sleep Arousal Scale, PSAS; Insomnia Severity Index, ISI; Dysfunctional Beliefs and Attitudes about Sleep, DBAS-30), mindfulness (Five-Facets Mindfulness Questionnaire, FFMQ), and mood and anxiety (Back Depression Inventory, BDI; State-Trait Anxiety Inventory, STAI). PSQI and PSAS (N = 26 to date) were collected at 6-month follow-up. Data were analysed with repeated-measures ANCOVA with group as a between-subject variable for the first 69 participants who completed the study. Results We observed significant improvement across both groups for sleep measures (PSQI: F1,67=36.442, p Conclusion Preliminary results support MBTI as an accessible but effective behavioural intervention with potential long-term benefits for improving sleep and mood, and reducing cognitive-emotional arousal in the elderly. Support This study was supported by an award from the 7th grant call of the Singapore Millennium Foundation Research Grant Programme

Introduction Sleep deprivation (SD) has a negative impact on the motivation to exert effort. This may contribute to the decline in attentional performance observed under SD. In this study we examined how SD affects motivated performance and effort-based decision making. Particularly, we used functional magnetic resonance imaging (fMRI) to uncover the neural mechanisms underlying the interplay between SD and motivated behavior. Methods Twenty-seven healthy subjects were tested once after a night of sleep in the lab (9h Time in Bed; Rested Wakefulness = RW), and once after a night of total sleep deprivation (SD). Participants performed an effortful attention task with different incentive levels (0, 10, or 50 cents/fast and correct response). Behavioral performance and fMRI data were collected during task performance. Subsequently, participants performed an effort-based choice task, during which they could choose to earn additional rewards for performing the attention task for a longer duration. Results As expected, attentional performance was worse in the SD session compared to the RW session. In addition, performance improved as a function of incentive level both in the RW and the SD session. This reward-effect was accompanied by increased activation in attention-related brain areas, and increased arousal-related thalamus activation. This reward-modulation was more extensive during RW than SD, particularly in the anterior cingulate cortex (ACC) and anterior insula (aIns; both areas involved in effort regulation). Results from the decision making task were less willing to perform the attention task for a further duration after SD compared to RW. Conclusion Results show that performance decline after SD is reward-dependent and willingness to perform is reduced. Reward modulation of attention-related brain activation is reduced, particularly in areas that are associated with effort regulation (i.e. ACC and aIns). These findings indicate that motivational factors contribute to decline of vigilance following sleep deprivation. Support This work was supported by grants awarded to Dr. Michael Chee from the National Medical Research Council (NMRC/STaR/0015/2013), and the Far East Organization.

Fronto‐parietal subnetworks were revealed to compensate for cognitive decline due to mental fatigue by community structure analysis. Here, we investigate changes in topology of subnetworks of resting‐state fMRI networks due to mental fatigue induced by prolonged performance of a cognitively demanding task, and their associations with cognitive decline. As it is well established that brain networks have modular organization, community structure analyses can provide valuable information about mesoscale network organization and serve as a bridge between standard fMRI approaches and brain connectomics that quantify the topology of whole brain networks. We developed inter‐ and intramodule network metrics to quantify topological characteristics of subnetworks, based on our hypothesis that mental fatigue would impact on functional relationships of subnetworks. Functional networks were constructed with wavelet correlation and a data‐driven thresholding scheme based on orthogonal minimum spanning trees, which allowed detection of communities with weak connections. A change from pre‐ to posttask runs was found for the intermodule density between the frontal and the temporal subnetworks. Seven inter‐ or intramodule network metrics, mostly at the frontal or the parietal subnetworks, showed significant predictive power of individual cognitive decline, while the network metrics for the whole network were less effective in the predictions. Our results suggest that the control‐type fronto‐parietal networks have a flexible topological architecture to compensate for declining cognitive ability due to mental fatigue. This community structure analysis provides valuable insight into connectivity dynamics under different cognitive states including mental fatigue.

While mindfulness is commonly viewed as a skill to be cultivated through practice, untrained individuals can also vary widely in dispositional mindfulness. Prior research has identified static neural connectivity correlates of this trait. Here, we use dynamic functional connectivity (DFC) analysis of resting-state fMRI to study time-varying connectivity patterns associated with naturally varying and objectively measured trait mindfulness. Participants were selected from the top and bottom tertiles of performers on a breath-counting task to form high trait mindfulness (HTM; N = 21) and low trait mindfulness (LTM; N = 18) groups. DFC analysis of resting state fMRI data revealed that the HTM group spent significantly more time in a brain state associated with task-readiness – a state characterized by high within-network connectivity and greater anti-correlations between task-positive networks and the default-mode network (DMN). The HTM group transitioned between brain states more frequently, but the dwell time in each episode of the task-ready state was equivalent between groups. These results persisted even after controlling for vigilance. Across individuals, certain connectivity metrics were weakly correlated with self-reported mindfulness as measured by the Five Facet Mindfulness Questionnaire, though these did not survive multiple comparisons correction. In the static connectivity maps, HTM individuals had greater within-network connectivity in the DMN and the salience network, and greater anti-correlations between the DMN and task-positive networks. In sum, DFC features robustly distinguish HTM and LTM individuals, and may be useful biological markers for the measurement of dispositional mindfulness.

Mindfulness based training (MBT) is becoming increasingly popular as a means to improve general wellbeing through developing enhanced control over metacognitive processes. In this preliminary study, we tested a cohort of 36 nurses (mean age = 30.3, S.D. = 8.52; 2 male) who participated in an 8-week MBT intervention to examine the improvements in sustained attention and its energetic costs that may result from MBT. Changes in sustained attention were measured using the Psychomotor Vigilance Task (PVT) and electroencephalography (EEG) was collected both during PVT performance, and during a brief period of meditation. As there was substantial variability in training attendance, this variable was used a covariate in all analyses. Following the MBT program, we observed changes in alpha power across all scalp regions during meditation that were correlated with attendance. Similarly, PVT performance worsened over the 8-week period, but that this decline was mitigated by good attendance on the MBT program. The subjective energy depletion due to PVT performance (measured using self-report on Likert-type scales) was also less in regular attendees. Finally, changes in known EEG markers of attention during PVT performance (P300 and alpha-band event-related desynchronisation) paralleled these behavioral shifts. Taken together, our data suggest that sustained attention and its associated costs may be negatively affected over time in the nursing profession, but that regular attendance of MBT may help to attenuate these effects. However, as this study contained no control condition, we cannot rule out that other factors (e.g. motivation, placebo effects) may also account for our findings.

Objective: We aimed to discover how varying the length of task breaks would affect the time-on-task effect in subsequent testing periods. Background: An important means of preventing errors and accidents caused by mental fatigue and time on task is to intersperse rest intervals within long work periods. Most studies of rest pauses to date have examined their effects in real-world tasks and settings, and their subtler effects on behavior, as measurable by laboratory paradigms, are not well understood. Method: We studied a group of 71 participants as they completed a 1-hr auditory oddball task with two rest opportunities. Rest intervals were 1, 5, or 10 min long. Results: Improvements in reaction time were significantly positively associated with length of the rest break. However, longer breaks were also associated with steeper decrements in performance in the subsequent task block. Across individuals, the amount of immediate improvement correlated with the extent of later decline. Conclusion: Our results support a resource/effort-allocation model of fatigue, whereby longer breaks bias participants toward greater effort expenditure on resumption of the task when cognitive resources may not have been fully replenished. Application: These findings may have implications for the refinement of work-rest schedules in industries where time-on-task degradation in performance is an important concern.

Moral judgments are not just the product of conscious reasoning, but also involve the integration of social and emotional information. Irrelevant disgust stimuli modulate moral judgments, with individual sensitivity determining the direction and size of effects across both hypothetical and incentive-compatible experimental designs. We investigated the neural circuitry underlying this modulation using fMRI in 19 individuals performing a moral judgment task with subliminal priming of disgust facial expressions. Our results indicate that individual changes in moral acceptability due to priming covaried with individual differences in activation within the dorsomedial prefrontal cortex (dmPFC). Further, whole-brain analyses identified changes in functional connectivity between the dmPFC and the temporal-parietal junction (TPJ). High sensitivity individuals showed enhanced functional connectivity between the TPJ and dmPFC, corresponding with deactivation in the dmPFC, and rating the moral dilemmas as more acceptable. Low sensitivity individuals showed the opposite pattern of results. Post-hoc, these findings replicated in the dorsal anterior cingulate cortex (daMCC), an adjacent region implicated in converting between objective and subjective valuation. This suggests a specific computational mechanism – that disgust stimuli modulate moral judgments by altering the integration of social information to determine the subjective valuation of the considered moral actions.

Numerous studies have revealed various working memory (WM)-related brain activities that originate from various cortical regions and oscillate at different frequencies. However, multi-frequency band analysis of the brain network in WM in the cortical space remains largely unexplored. In this study, we employed a graph theoretical framework to characterize the topological properties of the brain functional network in the theta and alpha frequency bands during WM tasks. Twenty-eight subjects performed visual n-back tasks at two difficulty levels, i.e., 0-back (control task) and 2-back (WM task). After preprocessing, Electroencephalogram (EEG) signals were projected into the source space and 80 cortical brain regions were selected for further analysis. Subsequently, the theta- and alpha-band networks were constructed by calculating the Pearson correlation coefficients between the power series (obtained by concatenating the power values of all epochs in each session) of all pairs of brain regions. Graph theoretical approaches were then employed to estimate the topological properties of the brain networks at different WM tasks. We found higher functional integration in the theta band and lower functional segregation in the alpha band in the WM task compared with the control task. Moreover, compared to the 0-back task, altered regional centrality was revealed in the 2-back task in various brain regions that mainly resided in the frontal, temporal and occipital lobes, with distinct presentations in the theta and alpha bands. In addition, significant negative correlations were found between the reaction time with the average path length of the theta-band network and the local clustering of the alpha-band network, which demonstrates the potential for using the brain network metrics as biomarkers for predicting the task performance during WM tasks. MOE (Min. of Education, S’pore) Published version

Performance deterioration over time, or time-on-task (TOT) effects, can be observed across a variety of tasks, but little attention has been paid to how TOT-related brain activity may differ based on task pacing and cognitive demands. Here, we employ a set of three closely related tasks to investigate the effect of these variables on fMRI activation and connectivity. When participants dictated the pace of their own responses, activation and network connectivity within the dorsal attention network (DAN) increased over short time scales (~2–3 min), a phenomenon that was not observed when participants had no control over their pace of work. Reaction time slowing was also the most pronounced in this self-paced task. In contrast, TOT-related changes in default-mode network (DMN) activity and connectivity, DAN-DMN anti-correlations, and pupil diameter did not differ based on pacing or task instructions. Over a longer (~10 min) time scale, task-positive activation and connectivity decreased in all paradigms, in agreement with older findings. These results highlight dynamic patterns of resource allocation that have not previously been observed in fMRI experiments, and speak to the idea that the brain may strategically allocate resources depending on the task at hand and the time scale of work.

Study Objectives: To characterize adolescents’ neurobehavioral changes during two cycles of restricted and recovery sleep and to examine the effectiveness of afternoon naps in ameliorating neurobehavioral deficits associated with multiple nights of sleep restriction. Methods: Fifty-seven healthy adolescents (aged 15–19 years; 31 males) participated in a parallel group study. They underwent two cycles of sleep restriction (5-hr time in bed [TIB] for five and three nights in the first and the second cycles, respectively; 01:00–06:00) and recovery (9-hr TIB for two nights per cycle; 23:00–08:00) intended to simulate the weekday sleep loss and weekend attempt to “catch up” on sleep. Half of the participants received a 1-hr nap opportunity at 14:00 following each sleep-restricted night, while the other half stayed awake. Sustained attention, sleepiness, speed of processing, executive function, and mood were assessed 3 times each day. Results: Participants who were not allowed to nap showed progressive decline in sustained attention that did not return to baseline after two nights of recovery sleep. Exposure to the second period of sleep restriction increased the rate of vigilance deterioration. Similar patterns were found for other neurobehavioral measures. Napping attenuated but did not eliminate performance decline. These findings contrasted with the stable performance of adolescents, given 9-hr TIB each night in our recent study. Conclusions: Adolescents’ neurobehavioral functions may not adapt to successive cycles of sleep curtailment and recovery. In sleep-restricted adolescents, weekend “catch-up sleep,” even when combined with napping during weekdays, is inferior to receiving a 9-hr sleep opportunity each night.

The use of silver nanoparticles (Ag NPs) within the healthcare sector and consumer products is rapidly increasing. There are now a range of diverse-shaped Ag NPs that are commercially available and many of the products containing nanosilver are topically applied to human skin. Currently, there is limited data on the extent to which the antimicrobial efficacy and cytotoxicity of Ag NPs is related to their shape and how the shape of the Ag NPs affects their distribution in both intact and burn wounded human skin after topical application. In this study, we related the relative Ag NP cytotoxicity to potential skin pathogens and HaCaT keratinocytes in vitro with the shape of the Ag NPs. We employed multiphoton fluorescence lifetime imaging to map the distribution of the native and unlabeled Ag NPs after topical application to both intact and burn wounded human skin using the localized surface plasmon resonance signal of the Ag NPs. Truncated plate shaped Ag NPs led to the highest cytotoxicity against both bacteria (IC50 ranges from 31.25 to 125 μg/mL depending on the bacterial species) and HaCaT keratinocytes (IC50 78.65 μg/mL [95%CI 63.88, 96.83]) thus both with similar orders of magnitude. All Ag NPs were less cytotoxic than solutions of silver nitrate (IC50 of 7.85 μg/mL [95%CI 1.49, 14.69]). Plate-shaped Ag NPs displayed the highest substantivity within the superficial layers of the stratum corneum when topically applied to intact skin and the highest deposition into the wound bed when applied to burned ex vivo human skin relative to other Ag NP shapes.

Numerous efforts have been devoted to revealing neurophysiological mechanisms of mental fatigue, aiming to find an effective way to reduce the undesirable fatigue-related outcomes. Until recently, mental fatigue is thought to be related to functional dysconnectivity among brain regions. However, the topological representation of brain functional connectivity altered by mental fatigue is only beginning to be revealed. In the current study, we applied a graph theoretical approach to analyse such topological alterations in the lower alpha band (8□10 Hz) of EEG data from 20 subjects undergoing a two-session experiment, in which one session includes four successive blocks with visual oddball tasks (session 1) whereas a mid-task break was introduced in the middle of four task blocks in the other session (session 2). Phase lag index (PLI) was then employed to measure functional connectivity strengths for all pairs of EEG channels. Behaviour and connectivity maps were compared between the first and last task blocks in both sessions. Inverse efficiency scores (IES = reaction time/ response accuracy) were significantly increased in the last task block, showing a clear effect of time-on-task in participants. Furthermore, a significant block-by-session interaction was revealed in the IES, suggesting the effectiveness of the mid-task break on maintaining task performance. More importantly, a significant session-independent deficit of global integration and an increase of local segregation were found in the last task block across both sessions, providing further support for the presence of a reshaped topology in functional brain connectivity networks under fatigue state. Moreover, a significant block-by-session interaction was revealed in the characteristic path length, small-worldness, and global efficiency, attributing to the significantly disrupted network topology in session 1 in comparison of the maintained network structure in session 2. Specifically, we found increased nodal betweenness centrality in several channels resided in frontal regions in session 1, resembling the observations of more segregated global architecture under fatigue state. Taken together, our findings provide insights into the substrates of brain functional dysconnectivity patterns for mental fatigue and reiterate the effectiveness of the mid-task break on maintaining brain network efficiency.

Although rest breaks are commonly administered as a countermeasure to reduce mental fatigue and boost cognitive performance, the effects of taking a break on behavior are not consistent. Moreover, our understanding of the underlying neural mechanisms of rest breaks and how they modulate mental fatigue is still rudimentary. In this study, we investigated the effects of receiving a rest break on the topological properties of brain connectivity networks via a two-session experimental paradigm, in which one session comprised four successive blocks of a mentally demanding visual selective attention task (No-rest session), whereas the other contained a rest break between the second and third task blocks (Rest session). Functional brain networks were constructed using resting-state functional MRI data recorded from 20 healthy adults before and after the performance of the task blocks. Behaviorally, subjects displayed robust time-on-task (TOT) declines, as reflected by increasingly slower reaction time as the test progressed and lower post-task self-reported ratings of engagement. However, we did not find a significant effect on task performance due to administering a mid-task break. Compared to pre-task measurements, post-task functional brain networks demonstrated an overall decrease of optimal small-world properties together with lower global efficiency. Specifically, we found TOT-related reduced nodal efficiency in brain regions that mainly resided in the subcortical areas. More interestingly, a significant block-by-session interaction was revealed in local efficiency, attributing to a significant post-task decline in No-rest session and a preserved local efficiency when a mid-task break opportunity was introduced in the Rest session. Taken together, these findings augment our understanding of how the resting brain reorganizes following the accumulation of prolonged task, suggest dissociable processes between the neural mechanisms of fatigue and recovery, and provide some of the first quantitative insights into the cognitive neuroscience of work and rest.

'Low back pain' (LBP) is a prevalent condition with a majority showing no specific organic pathology. Distinguishing 'secondary gain motives (SGM)' from organic causes is imperative in clinical practice. We describe here, three new tests-resistive straight leg raise test (rSLRT), resistive forward bend test (rFBT) and heel compression test (HCT) to help differentiate patients with 'SGM' from those without. We conducted a prospective study to validate the above tests in predicting non-organic causes as a reason for LBP.200 patients presenting with low back pain at the senior author's outpatient orthopaedic clinic from Jan 2009 to Nov 2010 were studied. Patients were separated into two groups-'SGM group' (n = 100) and 'non-SGM group' (n = 100). 'SGM group' patients had a history of work-related accidents, road traffic accidents or assault, with a background of ongoing litigation issues or compensation benefits. rSLRT, rFBT, HCT, Schober's test and Waddell's five signs were performed on them. Statistical analysis was done to identify correlations between test results, MRI findings and 'SGM' status.Statistically significant differences were observed between the SGM and non-SGM group (p 0.0005) for all tests studied. In predicting SGM status, rSLRT showed highest specificity (0.94) and highest positive predictive value (0.925) while HCT showed the highest negative predictive value (0.859). Positive rSLRT was found to be strongly correlated with ≥3 positive Waddell's signs. SGM patients with positive rSLRT tended to show resistance ≤45°.rSLRT, rFBT and HCT (NK triad) are highly practical tests which strongly predict SGM status in patients.

A substantial amount of research has been conducted in an effort to understand the impact of short-term (