Abstract Oxytocin is a nonapeptide that also serves as a neuromodulator in the human central nervous system. Over the last decade, a sizeable body of literature has examined its effects on social ...behavior in humans. These studies show that oxytocin modulates various aspects of social behaviors such as empathy, trust, in-group preference, and memory of socially relevant cues. Several theoretical formulations have attempted to explain the effects of oxytocin. The prosocial account argues that oxytocin mainly enhances affiliative prosocial behaviors; the fear/stress theory suggests that oxytocin affects social performance by attenuating stress; and the in-/out-group approach proposes that oxytocin regulates cooperation and conflict among humans in the context of intergroup relations. Nonetheless, accumulating evidence reveals that the effects of oxytocin are dependent on a variety of contextual aspects and the individual’s characteristics and can induce antisocial effects including aggression and envy. In an attempt to reconcile these accounts, we suggest a theoretical framework that focuses on the overarching role of oxytocin in regulating the salience of social cues through its interaction with the dopaminergic system. Crucially, the salience effect modulates attention orienting responses to external contextual social cues (e.g., competitive vs. cooperative environment) but is dependent on baseline individual differences such as gender, personality traits, and degree of psychopathology. This view could have important implications for the therapeutic applications of oxytocin in conditions characterized with aberrant social behavior.
Conceptual scientific and medical advances have led to a recent realization that there may be no single, one-size-fits-all diet and that differential human responses to dietary inputs may rather be ...driven by unique and quantifiable host and microbiome features. Integration of these person-specific host and microbiome readouts into actionable modules may complement traditional food measurement approaches in devising diets that are of benefit to the individual. Although many host-derived factors are hardwired and difficult to modulate, the microbiome may be more readily reshaped by environmental factors such as dietary exposures and is increasingly recognized to potentially impact human physiology by participating in digestion, the absorption of nutrients, shaping of the mucosal immune response and the synthesis or modulation of a plethora of potentially bioactive compounds. Thus, diet-induced microbiota alterations may be harnessed in order to induce changes in host physiology, including disease development and progression. However, major limitations in 'big-data' processing and analysis still limit our interpretive and translational capabilities concerning these person-specific host, microbiome and diet interactions. In this Review, we describe the latest advances in understanding diet-microbiota interactions, the individuality of gut microbiota composition and how this knowledge could be harnessed for personalized nutrition strategies to improve human health.
Identifying brain biomarkers of disease risk is a growing priority in neuroscience. The ability to identify meaningful biomarkers is limited by measurement reliability; unreliable measures are ...unsuitable for predicting clinical outcomes. Measuring brain activity using task functional MRI (fMRI) is a major focus of biomarker development; however, the reliability of task fMRI has not been systematically evaluated. We present converging evidence demonstrating poor reliability of task-fMRI measures. First, a meta-analysis of 90 experiments (N = 1,008) revealed poor overall reliability—mean intraclass correlation coefficient (ICC) = .397. Second, the test-retest reliabilities of activity in a priori regions of interest across 11 common fMRI tasks collected by the Human Connectome Project (N = 45) and the Dunedin Study (N = 20) were poor (ICCs = .067–.485). Collectively, these findings demonstrate that common task-fMRI measures are not currently suitable for brain biomarker discovery or for individual-differences research. We review how this state of affairs came to be and highlight avenues for improving task-fMRI reliability.
Individual differences in cognitive paradigms are increasingly employed to relate cognition to brain structure, chemistry, and function. However, such efforts are often unfruitful, even with the most ...well established tasks. Here we offer an explanation for failures in the application of robust cognitive paradigms to the study of individual differences. Experimental effects become well established – and thus those tasks become popular – when between-subject variability is low. However, low between-subject variability causes low reliability for individual differences, destroying replicable correlations with other factors and potentially undermining published conclusions drawn from correlational relationships. Though these statistical issues have a long history in psychology, they are widely overlooked in cognitive psychology and neuroscience today. In three studies, we assessed test-retest reliability of seven classic tasks: Eriksen Flanker, Stroop, stop-signal, go/no-go, Posner cueing, Navon, and Spatial-Numerical Association of Response Code (SNARC). Reliabilities ranged from 0 to .82, being surprisingly low for most tasks given their common use. As we predicted, this emerged from low variance between individuals rather than high measurement variance. In other words, the very reason such tasks produce robust and easily replicable experimental effects – low between-participant variability – makes their use as correlational tools problematic. We demonstrate that taking such reliability estimates into account has the potential to qualitatively change theoretical conclusions. The implications of our findings are that well-established approaches in experimental psychology and neuropsychology may not directly translate to the study of individual differences in brain structure, chemistry, and function, and alternative metrics may be required.
The COVID-19 pandemic has considerably impacted many people's lives. This study examined changes in subjective wellbeing between December 2019 and May 2020 and how stress appraisals and coping ...strategies relate to individual differences and changes in subjective wellbeing during the early stages of the pandemic. Data were collected at 4 time points from 979 individuals in Germany. Results showed that, on average, life satisfaction, positive affect, and negative affect did not change significantly between December 2019 and March 2020 but decreased between March and May 2020. Across the latter timespan, individual differences in life satisfaction were positively related to controllability appraisals, active coping, and positive reframing, and negatively related to threat and centrality appraisals and planning. Positive affect was positively related to challenge and controllable-by-self appraisals, active coping, using emotional support, and religion, and negatively related to threat appraisal and humor. Negative affect was positively related to threat and centrality appraisals, denial, substance use, and self-blame, and negatively related to controllability appraisals and emotional support. Contrary to expectations, the effects of stress appraisals and coping strategies on changes in subjective wellbeing were small and mostly nonsignificant. These findings imply that the COVID-19 pandemic represents not only a major medical and economic crisis, but also has a psychological dimension, as it can be associated with declines in key facets of people's subjective wellbeing. Psychological practitioners should address potential declines in subjective wellbeing with their clients and attempt to enhance clients' general capability to use functional stress appraisals and effective coping strategies.
Public Significance Statement
This study shows that, on average, life satisfaction, positive affect, and negative affect decreased across the early stages of the COVID-19 pandemic in Germany. Different stress appraisals and coping strategies relevant to the pandemic were associated with general levels of subjective wellbeing during the pandemic, but had only small and mostly nonsignificant effects on changes in subjective wellbeing over time. Psychological practitioners should address potential declines in subjective wellbeing with their clients and attempt to enhance clients' general capability to make use of functional stress appraisals and effective coping strategies during a pandemic.
Measurement of pupil size (pupillometry) has recently gained renewed interest from psychologists, but there is little agreement on how pupil-size data is best analyzed. Here we focus on one aspect of ...pupillometric analyses: baseline correction, i.e., analyzing changes in pupil size relative to a baseline period. Baseline correction is useful in experiments that investigate the effect of some experimental manipulation on pupil size. In such experiments, baseline correction improves statistical power by taking into account random fluctuations in pupil size over time. However, we show that baseline correction can also distort data if unrealistically small pupil sizes are recorded during the baseline period, which can easily occur due to eye blinks, data loss, or other distortions. Divisive baseline correction (corrected pupil size = pupil size/baseline) is affected more strongly by such distortions than subtractive baseline correction (corrected pupil size = pupil size − baseline). We discuss the role of baseline correction as a part of preprocessing of pupillometric data, and make five recommendations: (1) before baseline correction, perform data preprocessing to mark missing and invalid data, but assume that some distortions will remain in the data; (2) use subtractive baseline correction; (3) visually compare your corrected and uncorrected data; (4) be wary of pupil-size effects that emerge faster than the latency of the pupillary response allows (within ±220 ms after the manipulation that induces the effect); and (5) remove trials on which baseline pupil size is unrealistically small (indicative of blinks and other distortions).
Advances in technical capabilities for reading complex human microbiomes are leading to an explosion of microbiome research, leading in turn to intense interest among clinicians in applying these ...techniques to their patients. In this review, we discuss the content of the human microbiome, including intersubject and intrasubject variability, considerations of study design including important confounding factors, and different methods in the laboratory and on the computer to read the microbiome and its resulting gene products and metabolites. We highlight several common pitfalls for clinicians, including the expectation that an individual's microbiome will be stable, that diet can induce rapid changes that are large compared with the differences among subjects, that everyone has essentially the same core stool microbiome, and that different laboratory and computational methods will yield essentially the same results. We also highlight the current limitations and future promise of these techniques, with the expectation that an understanding of these considerations will help accelerate the path toward routine clinical application of these techniques developed in research settings.
Human Gut Microbiome: Function Matters Heintz-Buschart, Anna; Wilmes, Paul
Trends in microbiology (Regular ed.),
July 2018, 2018-07-00, 20180701, Letnik:
26, Številka:
7
Journal Article
Recenzirano
The human gut microbiome represents a complex ecosystem contributing essential functions to its host. Recent large-scale metagenomic studies have provided insights into its structure and functional ...potential. However, the functional repertoire which is actually contributed to human physiology remains largely unexplored. Here, by leveraging recent omics datasets, we challenge current assumptions regarding key attributes of the functional gut microbiome, in particular with respect to its variability. We further argue that the closing of existing gaps in functional knowledge should be addressed by a most-wanted gene list, the development and application of molecular and cellular high-throughput measurements, the development and sensible use of experimental models, as well as the direct study of observable molecular effects in the human host.
Functional omics are becoming more accessible, and increasing numbers of studies have employed them, demonstrating their potential in identifying functional traits of the microbiome related to health and disease.
Functional omes display greater variability and sensitivity to perturbation, also in cases of where changes in taxonomic composition are minimal, and they can resolve gut-compartment-specific information.
Methods for resolving functional differences in meta-omic datasets to the taxa contributing them have been developed and are necessary to understand the impact of microbial functions on human physiology.
'Enriched environments' are a key experimental paradigm to decipher how interactions between genes and environment change the structure and function of the brain across the lifespan of an animal. The ...regulation of adult hippocampal neurogenesis by environmental enrichment is a prime example of this complex interaction. As each animal in an enriched environment will have a slightly different set of experiences that results in downstream differences between individuals, enrichment can be considered not only as an external source of rich stimuli but also to provide the room for individual behaviour that shapes individual patterns of brain plasticity and thus function.
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