The Role of Sleep for Age-Related Differences in Neurobehavioral Performance.

This study investigated developmental changes from childhood to adulthood in neurobehavioral performance and sleep measures. While many studies have examined age-related changes between childhood and adolescence and from mid-to-late adulthood, young adulthood has been overlooked. The main aim of this study was to investigate the effects of sleep loss on developmental changes in neurobehavioral performance and sleepiness in a natural setting. A total of 119 children, adolescents, and young adults (38 children aged 6-9; 38 adolescents aged 13-19; and 43 young adults aged 20-27) wore an actigraph for a continuous five-weekday night. Subjective sleepiness (Karolinska Sleepiness Scale) and neurobehavioral performance (using the psychomotor vigilance test and the digit symbol substitution test) were measured on five school days. The results showed that adolescents and young adults outperformed children on both the digit symbol substitution test and the psychomotor vigilance test measures. However, adolescents committed more errors of commission on the psychomotor vigilance test and reported higher levels of subjective sleepiness. The results are discussed in relation to brain maturation in various cognitive functions.

State Anxiety and Procrastination: The Moderating Role of Neuroendocrine Factors.

Procrastination is prevalent among students, as well as the general population, and has negative impacts on various domains. Several models aimed to understand factors associated with procrastination, with some suggesting that anxiety plays a significant role. Biological factors have been shown to contribute to individual differences in procrastination; however, little attention has been paid to the role of neuroendocrine factors on procrastination. The primary question addressed in the present study is whether neuroendocrine factors (testosterone and cortisol) moderate the association between state anxiety and procrastination. Eighty-eight participants (29 men; 32 women using oral contraceptives; and 27 women not using oral contraceptives and in their luteal phase) were tested for biomarkers and completed questionnaires. Results show that state anxiety is positively correlated with procrastination. Furthermore, testosterone levels moderate the correlation between state anxiety and procrastination. As testosterone levels drop, the positive correlation between state anxiety and procrastination becomes stronger, but when testosterone levels are higher, no significant association between state anxiety and procrastination is found. Cortisol levels do not moderate the relationship between state anxiety and procrastination. The role of neuroendocrine factors for psychological outcomes is discussed.

The Role of Sleep Patterns from Childhood to Adolescence in Vigilant Attention.

Only a few studies addressed age-related changes from childhood to adolescence in sleep patterns, sleepiness, and attention. Vigilant attention plays a key role in cognitive performance. While its nature and course have been investigated broadly among adults, only limited research has been conducted on its development between childhood and adolescence. The main aim of the current study was to replicate previous findings about the effects of sleep loss on age-related changes in vigilance attention performance and sleepiness in a natural setting. A total of 104 children and adolescents (46 children aged 6-9 and 58 adolescents aged 13-19) wore an actigraph for a continuous five to seven nights, including weekdays and weekends. Subjective sleepiness (Karolinska Sleepiness Scale) and a Psychomotor Vigilance Test (PVT-B) were measured on two school days and one non-school day. Findings showed that PVT-B performance differed by age group, with adolescents outperforming children in PVT-B measures in spite of their elevated subjective sleepiness. Adolescents demonstrated less sleep time and increased sleepiness. Although PVT-B performance was better among adolescents, a within-subject analysis revealed that adolescents performed better on PVT measures on weekends than on weekdays. The results are discussed in relation to the synaptic elimination model.

The Role of Endocrine Stress Systems and Sex Hormones in the Enhancing Effects of Stress on Mental Rotation Capabilities.

The possible effects of stress and neurobiological stress mechanisms on visuospatial abilities remain largely unknown. In the current study, we examined the combined effect of sex hormones and both the hypothalamic-pituitary-adrenal axis (HPA-A) and the sympathetic nervous system (SNS) on stress-induced changes in visuospatial performance. A total of 107 participants completed a mental rotation task and were subsequently exposed to either to the Trier social stress test (TSST) or to a control condition before completing the mental rotation task again. HPA-A and SNS reactivity of the participants were evaluated by measuring salivary alpha amylase (sAA; an SNS activation marker) and cortisol in four saliva samples. Pre-stress levels of sex hormones (progesterone, estradiol, and testosterone) were also measured. The TSST enhanced mental rotation performance, and this enhancement was negatively correlated with baseline estradiol levels and positively correlated with the level of cortisol reactivity among men. In addition, controlling for baseline levels of testosterone, estradiol, and progesterone diminished this effect of stress. These results imply that the stress-induced facilitation of mental rotation performance is modulated by baseline sex hormones and provide preliminary support to the notion that a complex interaction between sex hormones and neuroendocrine stress mechanisms mediates the influence of stress on visuospatial performance.

Quantifying the Predictive Role of Temperament Dimensions and Attachment Styles on the Five Factor Model of Personality.

BACKGROUND: The present study investigated the role of temperament and attachment security in predicting individual differences in the five factor personality traits among adults. As previous studies suggested the potential moderating role of attachment in the association between temperament and personality traits, the present study sought to examine an interactionist model combining attachment and temperament in explaining individual differences in personality traits. METHODS: A sample of 1871 participants (1151 women and 719 men) completed self-report measures of adult attachment style (the Relationships Questionnaire-RQ), temperament dimension (the Fisher Temperament Inventory-FTI), and personality domain (the Five Factor Model-FFM). RESULTS: Partial correlational analyses revealed associations between attachment security and each of the five domains of the FFM, and few associations between some temperament dimensions and several domains of the FFM. Moderated regression analyses showed that attachment security moderated the associations between temperament dimensions and the Agreeableness domain of the FFM. Among secure individuals, those with higher scores on the Curious/Energetic, Cautious/Social Norm Compliant and Prosocial/Empathetic scales exhibited higher Agreeableness scores, whereas among insecure individuals, those with higher scores on the Analytic/Tough-minded scale exhibited lower scores on the Agreeableness scale. CONCLUSION: Overall, the current study provides evidence in support of the substantive role of social-environmental factors (Adult Attachment) as a moderating element bridging temperament-related personality elements and a number of their FFM manifestations.

Interactive role of endocrine stress systems and reproductive hormones in the effects of stress on declarative memory.

The effects of stress on memory performance, and the neuroendocrine mechanisms mediating such effects, are not well understood. Given the interrelationship between reproductive hormones and both the sympathetic nervous system (SNS) and the hypothalamic-pituitary-adrenal axis (HPA-A), we examined their combined effect on stress-induced modulation of declarative memory. Before and after exposure either to the Trier Social Stress Test (TSST) procedure or to a non-stress condition, 112 participants completed the Rey Auditory Verbal Learning Test. We analyzed participants' HPA-A and SNS reactivity by measuring cortisol and salivary alpha-amylase (sAA, an SNS activation marker) in four saliva samples. In addition, testosterone, estradiol, and progesterone were sampled prior to the stress exposure. Exposure to the TSST attenuated memory recall after an introduction of an interference list during the declarative memory task. Importantly, controlling for testosterone, estradiol, and progesterone diminished this effect of stress, suggesting the importance of baseline reproductive hormones in stress-induced modulation of memory functions. Furthermore, a multiple regression model revealed that stress-induced declines in memory performance were negatively associated with participants' stress-induced cortisol reactivity, but only among individuals with high testosterone levels. In addition, stress-induced declines in memory performance were negatively associated with participants' stress-induced increases in sAA, but only in individuals with low progesterone levels. These findings suggest that the effects of stress on memory performance may be modulated by baseline reproductive hormones and provide a preliminary indication for specific modulatory interrelationships between reproductive hormones and neuroendocrine stress mechanisms in mediating the effects of stress on memory.

The Relation between Sustained Attention and Incidental and Intentional Object-Location Memory.

The role of attention allocation in object-location memory has been widely studied through incidental and intentional encoding conditions. However, the relation between sustained attention and memory encoding processes has scarcely been studied. The present study aimed to investigate performance differences across incidental and intentional encoding conditions using a divided attention paradigm. Furthermore, the study aimed to examine the relation between sustained attention and incidental and intentional object-location memory performance. Based on previous findings, an all women sample was recruited in order to best illuminate the potential effects of interest. Forty-nine women participated in the study and completed the psychomotor vigilance test, as well as object-location memory tests, under both incidental and intentional encoding divided attention conditions. Performance was higher in the incidental encoding condition than in the intentional encoding condition. Furthermore, sustained attention correlated with incidental, but not with intentional memory performance. These findings are discussed in light of the automaticity hypothesis, specifically as it regards the role of attention allocation in encoding object-location memory. Furthermore, the role of sustained attention in incidental memory performance is discussed in light of previous animal and human studies that have examined the brain regions involved in these cognitive processes. We conclude that under conditions of increased mental demand, executive attention is associated with incidental, but not with intentional encoding, thus identifying the exact conditions under which executive attention influence memory performance.

Effects of attention during encoding on sex differences in object location memory.

Attention plays a key role in memory processes and has been widely studied in various memory tasks. The role of attention in sex differences in object location memory is not clearly understood. In the present study, two experiments involving 186 participants and using an object array presented on paper were conducted to examine two encoding conditions: incidental and intentional. In each experiment, the participants were randomly assigned to divided versus full attention conditions. In the first experiment, which involved incidental encoding, women outperformed men in memorising location-exchanged objects in both the full and in the divided attention condition. In the second experiment, which involved intentional encoding, women outperformed men in memorising location-exchanged objects in the full attention condition, but not the divided attention condition. These findings deepen our knowledge regarding the role of attention in object location memory, specifically in terms of the conditions under which females have an advantage for detecting changes in an array of objects.

Gonadal hormones modulate the HPA-axis and the SNS in response to psychosocial stress.

Exposure to stress activates both the hypothalamus-pituitary-adrenal (HPA) axis and the sympathetic nervous system (SNS). A growing body of research points to the contribution of sex hormones (testosterone, estrogen, and progesterone), the end products of the hypothalamus-pituitary-gonadal (HPG) axis, in modulating stress reactivity. The present study aimed at investigating the potential modulating role of sex hormones on HPA and SNS reactivity to psychosocial stress. The reactivity, induced by the Trier Social Stress Test, was analyzed by measuring the levels of cortisol and alpha-amylase (markers for SNS activity) in four saliva samples each of 21 men and 37 women (17 not using oral contraceptives and in their luteal phase, and 20 women using oral contraceptives). In addition, basal sex hormones were sampled prior to the psychosocial stress exposure. Results revealed that controlling for testosterone, estrogen, and progesterone diminished the impact of stress on cortisol reactivity and on alpha-amylase reactivity. Moreover, controlling for sex hormones also diminished the differential pattern of cortisol reactivity in each experimental group among responders. Furthermore, correlation analyses revealed differences between groups in the association between sex hormones and alpha-amylase. The present findings indicate a modulatory role for sex hormones in HPA and SNS reactivity and emphasize the need for control of sex hormone fluctuations when examining cortisol and alpha-amylase reactivity to stress.

Age and Sex Differences in Verbal and Visuospatial Abilities.

In order to explore the developmental patterns of sex differences in verbal and visuospatial abilities, the present study investigated sex differences in various cognitive abilities among children and adults. Three hundred and twenty-six children and adults completed a battery of six cognitive tasks testing two sets of abilities: The verbal cognitive battery tested verbal fluency and short-term memory tasks. The visuospatial battery tested mental rotation, localization, and form-completion tasks. Results showed a significant Sex × Age interaction on the mental rotation task, with men outperforming women in the 3D task, but with no sex differences shown in childhood in the 2D task. Sex differences in verbal fluency were found, with girls and women outperforming boys and men in this task. Findings are discussed within an integrative approach of biological as well as environmental factors.

The role of attentional resources in explaining sex differences in object location memory.

Sex differences in object location memory have been widely studied, with mixed results. The role of attention in mediating the female advantage in object location memory has not been clearly understood yet. Two experiments, involving 181 participants and using an actual object array, were conducted in the present study to examine two learning conditions: incidental and intentional. In each experiment, participants were randomly assigned to divided versus full attention conditions. The study also examined memorizing location-maintained and location-exchanged objects. In both experiments, in both incidental and intentional learning conditions, women outperformed men in memorizing location-exchanged objects in the full but not in the divided attention condition. These findings confirm and extend previous ones concerning the conditions under which the female advantage in the detection of change in an array of objects occurs. The findings are discussed within an evolutionary conceptual framework.

Sex Hormone/Cortisol Ratios Differentially Modulate Risk-Taking in Men and Women.

The present study aimed to extend the original focus of the dual-hormone hypothesis on testosterone and cortisol involvement in risk-taking to other sex hormones: estrogen and progesterone. The study also examined two alternative models for the proposed relationship between cortisol and sex steroids and for their joint influence on risk-taking: interaction and ratio terms. In all, 40 women and 37 men were tested for circulating sex hormones and provided self-reports on risk-taking. The findings suggest that sex hormone-cortisol ratios differentially modulate risk-taking in men and women: In men, high ratios were associated with risk-taking, whereas in women the opposite pattern was found. The findings are discussed in light of evolutionary assumptions regarding sex differences in neuroendocrine mechanisms, suggesting sex differences in neural sensitivity to sex hormones in risk-taking.

Surviving the Holocaust: a meta-analysis of the long-term sequelae of a genocide.

The current set of meta-analyses elucidates the long-term psychiatric, psychosocial, and physical consequences of the Holocaust for survivors. In 71 samples with 12,746 participants Holocaust survivors were compared with their counterparts (with no Holocaust background) on physical health, psychological well-being, posttraumatic stress symptoms, psychopathological symptomatology, cognitive functioning, and stress-related physiology. Holocaust survivors were less well adjusted, as apparent from studies on nonselected samples (trimmed combined effect size d = 0.22, 95% CI [0.13, 0.31], N = 9,803) and from studies on selected samples (d = 0.45, 95% CI [0.32, 0.59], N = 2,943). In particular, they showed substantially more posttraumatic stress symptoms (nonselect studies: d = 0.72, 95% CI [0.46, 0.98], N = 1,763). They did not lag, however, much behind their comparisons in several other domains of functioning (i.e., physical health, stress-related physical measures, and cognitive functioning) and showed remarkable resilience. The coexistence of stress-related symptoms and good adaptation in some other areas of functioning may be explained by the unique characteristics of the symptoms of Holocaust survivors, who combine resilience with the use of defensive mechanisms. In most domains of functioning no differences were found between Israeli samples and samples from other countries. The exception was psychological well-being: For this domain it was found that living in Israel rather than elsewhere can serve as a protective factor. A biopsychological stress-diathesis model is used to interpret the findings, and future directions for research and social policy are discussed.