Using noninvasive imaging to assess manual lymphatic drainage on lymphatic/venous responses in a spaceflight analog

This retrospective case series (clinicaltrials.gov NCT06405282) used noninvasive imaging devices (NIID) to assess the effect of manual lymphatic drainage (MLD) on dermal/venous fluid distribution, perfusion, and temperature alterations of the head, neck, upper torso, and legs while in the 6-degree head-down tilt validated spaceflight analog. A lymphatic fluid scanner measured tissue dielectric constant levels. Near-infrared spectroscopy assessed perfusion, by measuring tissue oxygenation saturation. Long-wave infrared thermography measured tissue temperature gradients. Fifteen healthy, university students participated. NIID assessments were taken 1 minute after assuming the HDT position and then every 30 minutes, with MLD administered from 180 to 195 minutes. Subjects returned to the sitting position and were assessed at post-225 min NIID demonstrated significant changes from baseline (p < 0.01), although these changes at areas of interest varied. MLD had a reverse effect on all variables. NIID assessment supported the potential use of MLD to mitigate fluid shifts during a spaceflight analog.

Data simulations for advancing psychological research: Insights, preparations and investigations

Simulation has become an essential tool in psychological research, offering unique insights into statistical concepts, optimising research project planning and modelling human behaviour and cognition. This tutorial navigates simulations' diverse applications across various research stages. This tutorial begins by demonstrating simulations' impact on understanding statistical concepts. Amidst growing demands for effect size reporting and interpretation, simulations can help clarify the relationship between data and effect sizes, benefiting both educational purposes and advanced research. Simulations play a crucial role in planning psychological research. They provide flexible solutions for power, helping to determine necessary sample sizes and aiding in robust research planning, providing evidence of planned procedures. Simulations are pivotal in exploring human behaviour and cognition, as well as statistical method properties. By forcing researchers to translate verbal theory into formal models, simulation can help specify the assumptions. The paper also discusses improving simulation efficiency, such as using calculation clusters, optimising simulation practices and recognises simulations' limitations. This paper emphasises simulations' versatile role in psychological research. They enable deep insights into complex datasets, streamline project preparation and uncover subtleties in human behaviour, cognition and statistical methodologies.

Genomic signature for oligometastatic disease in non-small cell lung cancer patients with brain metastases

Purpose/objectives

Biomarkers for extracranial oligometastatic disease remain elusive and few studies have attempted to correlate genomic data to the presence of true oligometastatic disease.

Methods

Patients with non-small cell lung cancer (NSCLC) and brain metastases were identified in our departmental database. Electronic medical records were used to identify patients for whom liquid biopsy-based comprehensive genomic profiling (Guardant Health) was available. Extracranial oligometastatic disease was defined as patients having ≤5 non-brain metastases without diffuse involvement of a single organ. Widespread disease was any spread beyond oligometastatic. Fisher's exact tests were used to screen for mutations statistically associated (p<0.1) with either oligometastatic or widespread extracranial disease. A risk score for the likelihood of oligometastatic disease was generated and correlated to the likelihood of having oligometastatic disease vs widespread disease. For oligometastatic patients, a competing risk analysis was done to assess for cumulative incidence of oligometastatic progression. Cox regression was used to determine association between oligometastatic risk score and oligoprogression.

Results

130 patients met study criteria and were included in the analysis. 51 patients (39%) had extracranial oligometastatic disease. Genetic mutations included in the Guardant panel that were associated (p<0.1) with the presence of oligometastatic disease included ATM, JAK2, MAP2K2, and NTRK1, while ARID1A and CCNE1 were associated with widespread disease. Patients with a positive, neutral and negative risk score for oligometastatic disease had a 78%, 41% and 11.5% likelihood of having oligometastatic disease, respectively (p<0.0001). Overall survival for patients with positive, neutral and negative risk scores for oligometastatic disease was 86% vs 82% vs 64% at 6 months (p=0.2). Oligometastatic risk score was significantly associated with the likelihood of oligoprogression based on the Wald chi-square test. Patients with positive, neutral and negative risk scores for oligometastatic disease had a cumulative incidence of oligometastatic progression of 77% vs 35% vs 33% at 6 months (p=0.03).

Conclusions

Elucidation of a genomic signature for extracranial oligometastatic disease derived from non-invasive liquid biopsy appears feasible for NSCLC patients. Patients with this signature exhibited higher rates of early oligoprogression. External validation could lead to a biomarker that has the potential to direct local therapies in oligometastatic patients.

Are alternative variables in a set differently associated with a target variable? Statistical tests and practical advice for dealing with dependent correlations

The analysis of multiple bivariate correlations is often carried out by conducting simple tests to check whether each of them is significantly different from zero. In addition, pairwise differences are often judged by eye or by comparing the p-values of the individual tests of significance despite the existence of statistical tests for differences between correlations. This paper uses simulation methods to assess the accuracy (empirical Type I error rate), power, and robustness of 10 tests designed to check the significance of the difference between two dependent correlations with overlapping variables (i.e., the correlation between X1 and Y and the correlation between X2 and Y). Five of the tests turned out to be inadvisable because their empirical Type I error rates under normality differ greatly from the nominal alpha level of .05 either across the board or within certain sub-ranges of the parameter space. The remaining five tests were acceptable and their merits were similar in terms of all comparison criteria, although none of them was robust across all forms of non-normality explored in the study. Practical recommendations are given for the choice of a statistical test to compare dependent correlations with overlapping variables.

Wings of Change: aPKC/FoxP-dependent plasticity in steering motor neurons underlies operant self-learning in Drosophila

Background

Motor learning is central to human existence, such as learning to speak or walk, sports moves, or rehabilitation after injury. Evidence suggests that all forms of motor learning share an evolutionarily conserved molecular plasticity pathway. Here, we present novel insights into the neural processes underlying operant self-learning, a form of motor learning in the fruit fly Drosophila.

Methods

We operantly trained wild type and transgenic Drosophila fruit flies, tethered at the torque meter, in a motor learning task that required them to initiate and maintain turning maneuvers around their vertical body axis (yaw torque). We combined this behavioral experiment with transgenic peptide expression, CRISPR/Cas9-mediated, spatio-temporally controlled gene knock-out and confocal microscopy.

Results

We find that expression of atypical protein kinase C (aPKC) in direct wing steering motoneurons co-expressing the transcription factor FoxP is necessary for this type of motor learning and that aPKC likely acts via non-canonical pathways. We also found that it takes more than a week for CRISPR/Cas9-mediated knockout of FoxP in adult animals to impair motor learning, suggesting that adult FoxP expression is required for operant self-learning.

Conclusions

Our experiments suggest that, for operant self-learning, a type of motor learning in Drosophila, co-expression of atypical protein kinase C (aPKC) and the transcription factor FoxP is necessary in direct wing steering motoneurons. Some of these neurons control the wing beat amplitude when generating optomotor responses, and we have discovered modulation of optomotor behavior after operant self-learning. We also discovered that aPKC likely acts via non-canonical pathways and that FoxP expression is also required in adult flies.

Applying a synergistic mindsets intervention to an esports context

Affective responses during stressful, high-stakes situations can play an important role in shaping performance. For example, feeling shaky and nervous at a job interview can undermine performance, whereas feeling excited during that same interview can optimize performance. Thus, affect regulation-the way people influence their affective responses-might play a key role in determining high-stakes outcomes. To test this idea, we adapted a synergistic mindsets intervention (SMI) (Yeager et al. 2022 Nature 607, 512-520 (doi:10.1038/s41586-022-04907-7)) to a high-stakes esports context. Our approach was motivated by the idea that (i) mindsets both about situations and one's stress responses to situations can be shaped to help optimize stress responses, and (ii) challenge versus threat stress responses will be associated with improved outcomes. After a baseline performance task, we randomly assigned gamers (n = 300) either to SMI or a control condition in which they learned brain facts. After two weeks of daily gaming, gamers competed in a cash-prize tournament. We measured affective experiences before the matches and cardiovascular responses before and throughout the matches. Contrary to predictions, gamers did not experience negative affect (including feeling stressed), thus limiting the capacity for the intervention to regulate physiological responses and optimize performance. Compared with the control participants, synergistic mindsets participants did not show greater challenge responses or improved performance outcomes. Though our adaptation of Yeager et al.'s SMI did not optimize esports performance, our findings point to important considerations regarding the suitability of an intervention such as this to different performance contexts of varying degrees of stressfulness.

Migratory behaviours are risk-sensitive to physiological state in an elevational migrant

Accretion of body fat by animals is an important physiological adaptation that may underpin seasonal behaviours, especially where it modulates risk associated with a particular behaviour. Using movement data from male Sierra Nevada bighorn sheep (Ovis canadensis sierrae), we tested the hypothesis that migratory behaviours were risk-sensitive to physiological state (indexed by body fat). Sierra bighorn face severe winter conditions at high elevations and higher predation risk at lower elevations. Given that large body fat stores ameliorate starvation risk, we predicted that having small body fat stores would force animals to migrate to lower elevations with more abundant food supplies. We also predicted that body fat stores would influence how far animals migrate, with the skinniest animals migrating the furthest down in elevation (to access the most abundant food supplies at that time of year). Lastly, we predicted that population-level rates of switching between migratory tactics would be inversely related to body fat levels because as body fat levels decrease, animals exhibiting migratory plasticity should modulate their risk of starvation by switching migratory tactics. Consistent with our predictions, probability of migration and elevational distance migrated increased with decreasing body fat, but effects differed amongst metapopulations. Population-level switching rates also were inversely related to population-level measures of body fat prior to migration. Collectively, our findings suggest migration was risk-sensitive to physiological state, and failure to accrete adequate fat may force animals to make trade-offs between starvation and predation risk. In complex seasonal environments, risk-sensitive migration yields a layer of flexibility that should aid long-term persistence of animals that can best modulate their risk by attuning behaviour to physiological state.

Establishing circularity: development and validation of the circular work value scale (CWVS)

Objectives

Addressing the lack of German-language instruments, this study aims to develop a questionnaire that enables the measurement of work values. According to the theory of basic human values (Schwartz, 1992), a culturally fitting questionnaire is validated by covering constructs in the four broader dimensions of Social, Prestige, Intrinsic, and Extrinsic work values. Convergent, discriminant and incremental congruent validity are assessed.

Method

Data were collected in a cross-sectional online-based panel survey. Individuals working more than 20 h per week were included (N = 1,049). Using a genetic algorithm, an economical and valid questionnaire was designed to assess work values.

Results

The 11 work values are measurable with three items each. They provide a good fit to the data with support for strict measurement invariance. The empirical associations to estimate construct validity overall reflect expected relations to social and individualistic work motives, neuroticism, environmental awareness, and basic values. Furthermore, congruent incremental validity is supported with relations to value congruence of the person-organization fit, and multidimensional scaling supports the assumed theoretical circularity of the work values.

Implications

This study developed a questionnaire that enables a theory-based valid measurement of work values. The questionnaire allows practitioners to economically collect information about the value structure of employees or applicants. Future research should consider the development of work values over time and investigate whether more distinctive constructs provide a better fit in the nomological network.

Early childhood attachment stability to mothers, fathers, and both parents as a network: associations with parents' well-being, marital relationship, and child behavior problems

This study examines the stability of child attachment to mothers and fathers separately, and to both parents as a network between the infancy and preschool periods using a sample of 143 biparental families and their children (73 boys) recruited from the general population. Attachment was assessed at 15 months with the Strange Situation Procedure (SSP) and at 45 months with the Preschool Attachment Classification Coding System (PACS). First, results show no stability in attachment to mothers, to fathers, or to both parents as a network. Second, parents' mental health, life satisfaction, marital satisfaction, and child externalizing behavior are associated with attachment stability. Taken altogether, group comparisons reveal that children with a stable secure attachment to both parents as a network have parents with higher levels of well-being and exhibit less problem behaviors than children with 1) a stable secure attachment to one parent and an unstable attachment to the other parent (from secure to insecure or from insecure to secure), or 2) who never had a stable secure attachment to either parent. This study highlights the significance of attachment to both parents as a network over time as it is associated with developmental outcomes.

Estimating statistical power for ERP studies using the auditory N1, Tb, and P2 components

The N1, Tb, and P2 components of the event-related potential (ERP) are thought to reflect the sequential processing of auditory stimuli in the human brain. Despite their extensive use in biological, cognitive, and clinical neuroscience, there are no guidelines for how to appropriately power ERP studies using these components. In the present study, we investigated how the number of trials, number of participants, effect magnitude, and study design influenced statistical power. Using Monte Carlo simulations of ERP data from a passive listening task, we determined the probability of finding a statistically significant effect in 58,900 experiments repeated 1,000 times each. We found that as the number of trials, number of participants, and effect magnitude increased, so did statistical power. We also found that increasing the number of trials had a bigger effect on statistical power for within-subject designs than for between-subject designs, and that within-subject designs required a smaller number of trials and participants to provide the same level of statistical power for a given effect magnitude than between-subject designs. These results show that it is important to carefully consider these factors when designing ERP studies, rather than relying on tradition or anecdotal evidence. To improve the robustness and reproducibility of ERP research, we have built an online statistical power calculator (https://bradleynjack.shinyapps.io/ErpPowerCalculator), which we hope will allow researchers to estimate the statistical power of previous studies, as well as help them design appropriately-powered studies in the future.

Peri-Saccadic Orientation Identification Performance and Visual Neural Sensitivity Are Higher in the Upper Visual Field

Visual neural processing is distributed among a multitude of sensory and sensory-motor brain areas exhibiting varying degrees of functional specializations and spatial representational anisotropies. Such diversity raises the question of how perceptual performance is determined, at any one moment in time, during natural active visual behavior. Here, exploiting a known dichotomy between the primary visual cortex (V1) and superior colliculus (SC) in representing either the upper or lower visual fields, we asked whether peri-saccadic orientation identification performance is dominated by one or the other spatial anisotropy. Humans (48 participants, 29 females) reported the orientation of peri-saccadic upper visual field stimuli significantly better than lower visual field stimuli, unlike their performance during steady-state gaze fixation, and contrary to expected perceptual superiority in the lower visual field in the absence of saccades. Consistent with this, peri-saccadic superior colliculus visual neural responses in two male rhesus macaque monkeys were also significantly stronger in the upper visual field than in the lower visual field. Thus, peri-saccadic orientation identification performance is more in line with oculomotor, rather than visual, map spatial anisotropies.SIGNIFICANCE STATEMENT Different brain areas respond to visual stimulation, but they differ in the degrees of functional specializations and spatial anisotropies that they exhibit. For example, the superior colliculus (SC) both responds to visual stimulation, like the primary visual cortex (V1), and controls oculomotor behavior. Compared with the primary visual cortex, the superior colliculus exhibits an opposite pattern of upper/lower visual field anisotropy, being more sensitive to the upper visual field. Here, we show that human peri-saccadic orientation identification performance is better in the upper compared with the lower visual field. Consistent with this, monkey superior colliculus visual neural responses to peri-saccadic stimuli follow a similar pattern. Our results indicate that peri-saccadic perceptual performance reflects oculomotor, rather than visual, map spatial anisotropies.

Publication bias, statistical power and reporting practices in the Journal of Sports Sciences: potential barriers to replicability

Two factors that decrease the replicability of studies in the scientific literature are publication bias and studies with underpowered desgins. One way to ensure that studies have adequate statistical power to detect the effect size of interest is by conducting a-priori power analyses. Yet, a previous editorial published in the Journal of Sports Sciences reported a median sample size of 19 and the scarce usage of a-priori power analyses. We meta-analysed 89 studies from the same journal to assess the presence and extent of publication bias, as well as the average statistical power, by conducting a z-curve analysis. In a larger sample of 174 studies, we also examined a) the usage, reporting practices and reproducibility of a-priori power analyses; and b) the prevalence of reporting practices of t-statistic or F-ratio, degrees of freedom, exact p-values, effect sizes and confidence intervals. Our results indicate that there was some indication of publication bias and the average observed power was low (53% for significant and non-significant findings and 61% for only significant findings). Finally, the usage and reporting practices of a-priori power analyses as well as statistical results including test statistics, effect sizes and confidence intervals were suboptimal.

Using preregistration as a tool for transparent fNIRS study design

Significance

The expansion of functional near-infrared spectroscopy (fNIRS) methodology and analysis tools gives rise to various design and analytical decisions that researchers have to make. Several recent efforts have developed guidelines for preprocessing, analyzing, and reporting practices. For the planning stage of fNIRS studies, similar guidance is desirable. Study preregistration helps researchers to transparently document study protocols before conducting the study, including materials, methods, and analyses, and thus, others to verify, understand, and reproduce a study. Preregistration can thus serve as a useful tool for transparent, careful, and comprehensive fNIRS study design.

Aim

We aim to create a guide on the design and analysis steps involved in fNIRS studies and to provide a preregistration template specified for fNIRS studies.

Approach

The presented preregistration guide has a strong focus on fNIRS specific requirements, and the associated template provides examples based on continuous-wave (CW) fNIRS studies conducted in humans. These can, however, be extended to other types of fNIRS studies.

Results

On a step-by-step basis, we walk the fNIRS user through key methodological and analysis-related aspects central to a comprehensive fNIRS study design. These include items specific to the design of CW, task-based fNIRS studies, but also sections that are of general importance, including an in-depth elaboration on sample size planning.

Conclusions

Our guide introduces these open science tools to the fNIRS community, providing researchers with an overview of key design aspects and specification recommendations for comprehensive study planning. As such it can be used as a template to preregister fNIRS studies or merely as a tool for transparent fNIRS study design.

The epistemic and pragmatic function of dichotomous claims based on statistical hypothesis tests

Researchers commonly make dichotomous claims based on continuous test statistics. Many have branded the practice as a misuse of statistics and criticize scientists for the widespread application of hypothesis tests to tentatively reject a hypothesis (or not) depending on whether a p-value is below or above an alpha level. Although dichotomous claims are rarely explicitly defended, we argue they play an important epistemological and pragmatic role in science. The epistemological function of dichotomous claims consists in transforming data into quasibasic statements, which are tentatively accepted singular facts that can corroborate or falsify theoretical claims. This transformation requires a prespecified methodological decision procedure such as Neyman-Pearson hypothesis tests. From the perspective of methodological falsificationism these decision procedures are necessary, as probabilistic statements (e.g., continuous test statistics) cannot function as falsifiers of substantive hypotheses. The pragmatic function of dichotomous claims is to facilitate scrutiny and criticism among peers by generating contestable claims, a process referred to by Popper as “conjectures and refutations.” We speculate about how the surprisingly widespread use of a 5% alpha level might have facilitated this pragmatic function. Abandoning dichotomous claims, for example because researchers commonly misuse p-values, would sacrifice their crucial epistemic and pragmatic functions.

A Guide for Calculating Study-Level Statistical Power for Meta-Analyses

Meta-analysis is a popular approach in the psychological sciences for synthesizing data across studies. However, the credibility of meta-analysis outcomes depends on the evidential value of studies included in the body of evidence used for data synthesis. One important consideration for determining a study’s evidential value is the statistical power of the study’s design/statistical test combination for detecting hypothetical effect sizes of interest. Studies with a design/test combination that cannot reliably detect a wide range of effect sizes are more susceptible to questionable research practices and exaggerated effect sizes. Therefore, determining the statistical power for design/test combinations for studies included in meta-analyses can help researchers make decisions regarding confidence in the body of evidence. Because the one true population effect size is unknown when hypothesis testing, an alternative approach is to determine statistical power for a range of hypothetical effect sizes. This tutorial introduces the metameta R package and web app, which facilitates the straightforward calculation and visualization of study-level statistical power in meta-analyses for a range of hypothetical effect sizes. Readers will be shown how to reanalyze data using information typically presented in meta-analysis forest plots or tables and how to integrate the metameta package when reporting novel meta-analyses. A step-by-step companion screencast video tutorial is also provided to assist readers using the R package.