Sex-dependent multimodal response profiles to psychosocial stress.

Introduction: Sex differences in stress reactions are often reported in the literature. However, the sex-dependent interplay of different facets of stress is still not fully understood. Particularly in neuroimaging research, studies on large samples combining different indicators of stress remain scarce.

Fast accurate quantification of salivary cortisol and cortisone in a large-scale clinical stress study by micro-UHPLC-ESI-MS/MS using a surrogate calibrant approach.

Cortisol and cortisone are common markers for stress and thus preferentially analyzed in matrices that allow non-invasive sampling such as saliva. Though the major drawback of immunoassays is lack of specificity due to cross reactivities, they are still most commonly used for quantification of steroid hormones. To overcome such problems, sensitive methods based on liquid chromatography-mass spectrometry are becoming more and more accepted as the golden standard for steroid bioanalysis as they achieve accurate quantification at trace levels for multiple analytes in the same run.

The association of the 5-HTTLPR polymorphism and the response to different stressors in healthy males.

The experience of stress is related to individual wellbeing and vulnerability to psychopathology. Therefore, understanding the determinants of individual differences in stress reactivity is of great concern from a clinical perspective. The functional promotor polymorphism of the serotonin transporter gene (5-HTTLPR/rs25531) is such a factor, which has been linked to the acute stress response as well as the adverse effect of life stressors.

Sleep strengthens integration of spatial memory systems.

Spatial memory comprises different representational systems that are sensitive to different environmental cues, like proximal landmarks or local boundaries. Here we examined how sleep affects the formation of a spatial representation integrating landmark-referenced and boundary-referenced representations. To this end, participants ( = 42) were familiarized with an environment featuring both a proximal landmark and a local boundary.

Imaging stress: an overview of stress induction methods in the MR scanner.

Processing of acute stress has potential implications for mental and physical health. At the same time, individuals differ largely in how strongly they react to stress. Neuroimaging paradigms have been developed to characterize the neural underpinnings of the stress response in general and to understand the mechanisms that differentiate high and low susceptible individuals.

Exploring the fMRI based neural correlates of the dot probe task and its modulation by sex and body odor.

The dot probe task implicitly cues attention via emotional information, an effect which is especially pronounced for threat-related cues. However, several questions remain unexplored. The first one is whether chemosignals like the androgen-derivative androstadienone can influence such attentional biases.

Bayesian informed evidence against modulation of androstadienone-effects by genotypic receptor variants and participant sex: A study assessing Stroop interference control, mood and olfaction.

The androgen derivative androstadienone (AND) is present in human sweat and may act as human chemosignal. Though effects of AND have been reported with respect to emotional and cognitive processes, results have been highly inconsistent. For this reason, it is likely that AND-action is dependent on modulatory factors.

Sleep augments training-induced improvement in working memory in children and adults.

Sleep plays an important role in forming procedural motor memories. Whether sleep plays a similar role for cognitive procedures related to working memory function, is not yet clear. Here we investigated if sleep enhances training-induced improvements in working memory in children.

Effects of Sleep on Word Pair Memory in Children - Separating Item and Source Memory Aspects.

Word paired-associate learning is a well-established task to demonstrate sleep-dependent memory consolidation in adults as well as children. Sleep has also been proposed to benefit episodic features of memory, i.e.

10-Month-Old Infants Are Sensitive to the Time Course of Perceived Actions: Eye-Tracking and EEG Evidence.

Research has shown that infants are able to track a moving target efficiently - even if it is transiently occluded from sight. This basic ability allows prediction of when and where events happen in everyday life. Yet, it is unclear whether, and how, infants internally represent the of ongoing movements to derive predictions.

Sleep enhances knowledge of routes and regions in spatial environments.

Sleep is thought to preferentially consolidate hippocampus-dependent memory, and as such, spatial navigation. Here, we investigated the effects of sleep on route knowledge and explicit and implicit semantic regions in a virtual environment. Sleep, compared with wakefulness, improved route knowledge and also enhanced awareness of the semantic regionalization within the environment, whereas signs of implicit regionalization remained unchanged.

On the validity and generality of transfer effects in cognitive training research.

Evaluation of training effectiveness is a long-standing problem of cognitive intervention research. The interpretation of transfer effects needs to meet two criteria, generality and specificity. We introduce each of the two, and suggest ways of implementing them.

Comparing manual and automatic segmentation of hippocampal volumes: reliability and validity issues in younger and older brains.

We compared hippocampal volume measures obtained by manual tracing to automatic segmentation with FreeSurfer in 44 younger (20-30 years) and 47 older (60-70 years) adults, each measured with magnetic resonance imaging (MRI) over three successive time points, separated by four months. Retest correlations over time were very high for both manual and FreeSurfer segmentations. With FreeSurfer, correlations over time were significantly lower in the older than in the younger age group, which was not the case with manual segmentation.

Age-related differences in temporal and spatial dimensions of episodic memory performance before and after hundred days of practice.

Normal aging impairs the representation and integration (binding) of spatial and temporal context in episodic memory. We directly compare age differences in episodic memory in relation to processing spatial and temporal context. As part of the COGITO study, 101 younger and 103 older participants trained an object-location serial recall task for 100 sessions.

Normal aging increases discriminal dispersion in visuospatial short-term memory.

Computational models of cognitive aging propose that age-related decrements in cognitive performance, including short-term memory (STM), result from less distinct stimulus representations. When applied to visual STM, these models predict higher discriminal dispersion (L. L.

The dynamics of change in striatal activity following updating training.

Increases in striatal activity have been suggested to mediate training-related improvements in working-memory ability. We investigated the temporal dynamics of changes in task-related brain activity following training of working memory. Participants in an experimental group and an active control group, trained on easier tasks of a constant difficulty in shorter sessions than the experimental group, were measured before, after about 1 week, and after more than 50 days of training.

Cortical thickness changes following spatial navigation training in adulthood and aging.

A widespread network involving cortical and subcortical brain structures forms the neural substrate of human spatial navigation. Most studies investigating plasticity of this network have focused on the hippocampus. Here, we investigate age differences in cortical thickness changes evoked by four months of spatial navigation training in 91 men aged 20-30 or 60-70 years.

Spatial navigation training protects the hippocampus against age-related changes during early and late adulthood.

It is unknown whether lifestyle, including mental stimulation, and appropriate training interventions, may directly improve spatial navigation performance and its underlying neural substrates. Here we report that healthy younger and older men performing a cognitively demanding spatial navigation task every other day over 4 months display navigation-related gains in performance and stable hippocampal volumes that were maintained 4 months after termination of training. In contrast, control groups displayed volume decrements consistent with longitudinal estimates of age-related decline.

Performance-related increases in hippocampal N-acetylaspartate (NAA) induced by spatial navigation training are restricted to BDNF Val homozygotes.

Recent evidence indicates experience-dependent brain volume changes in humans, but the functional and histological nature of such changes is unknown. Here, we report that adult men performing a cognitively demanding spatial navigation task every other day over 4 months display increases in hippocampal N-acetylaspartate (NAA) as measured with magnetic resonance spectroscopy. Unlike measures of brain volume, changes in NAA are sensitive to metabolic and functional aspects of neural and glia tissue and unlikely to reflect changes in microvasculature.

Cognitive plasticity in adulthood and old age: gauging the generality of cognitive intervention effects.

Interventions enabling aging individuals to fulfill their plastic potential promise to postpone, attenuate, or even reverse the adverse effects of senescent brain changes on cognitive abilities and everyday competence in old age. Based on an overview of the concept of plasticity in lifespan development, we selectively review evidence from cognitive intervention studies and conclude that most of them have failed to observe generalizable performance improvements, as documented by the small size and scope of positive transfer to untrained tasks. We further note that generally accepted criteria for defining transfer distance are lacking, rendering the relevant evidence difficult to interpret.