Physiological Measures Research Articles

Assessment of impact of left ventricular flow state on myocardial blood flow using positron emission tomography and echocardiography

Abstract Background The relationship between left ventricular (LV) mass and myocardial blood flow (MBF) has been recognized as an important physiological measure of myocardial perfusion to match global metabolic demand. However, there is little information on the association between LV flow state and MBF. Purpose To investigate impact of LV flow state on MBF. Methods The study included 104 patients undergoing cardiac positron emission tomography (PET) and echocardiography for chest pain and/or dyspnoea. CT attenuation corrected rest/regadenoson stress 13N-ammonia myocardial perfusion imaging was acquired with a PET CT camera. All images were acquired in 3-D list mode. Sixteen dynamic frames were reconstructed and analyzed with QPET software to obtain rest quantitative MBF measurements adjusted for rate-pressure product in ml/min/g, with a myocardial flow reserve (MFR) derived as the ratio of stress MBF/resting MBF. All patients had no ischaemia or infarction with LV ejection fraction ≥55%. Echocardiography was performed within 6 months of PET in clinically stable conditions allowing for. SV was measured by Doppler echocardiography using the continuity equation and was indexed by body surface area (SVi). The patients were divided to normal flow group (NFS: SVi > 35 ml/m2) and low flow group (LFS: SVi≤35 ml/m2). Results The mean SVi was 40 ml/m2 for NFS and 29 ml/m2 for LFS (p<0.001). LFS group was younger (57 ± 11 vs. 67 ± 11 years, p<0.001) with higher body mass index (43±8 vs. 37±8 kg/m2, p<0.001) and lower resting MBF (0.84±0.22 vs. 1.02±0.34 ml/min/g, p<0.01) than NFS groups. There were no significant differences of hypertension (81% vs. 82%, p> 0.05), LV mass index (82±21 vs. 88±82 g/m2, p>0.05), LVEF (63% vs. 65%, p>0.05) between LFS and NFS groups. SVi was positively associated with MBF as a whole group (r= 0.38, p<0.01). However, this significant association was only observed in NFS group (r=0.62, p <0.001), but not in LFS group (r=0.048, p= 0.46, Figure). Conclusion LFS expressed low MBF and the dissociation between SVi and MBF in comparison with NFS group suggesting potential alterations in relationships between myocardial work (SV) and oxygen consumption (MBF) in LFS. Further studies are warranted to investigate the pathophysiology behind the findings and to correlate with a long-term clinical outcome.

The impact of hydrostatic pressure on fractional flow reserve in saphenous vein grafts

Abstract Background Intracoronary physiological measurements can be subject to the influence of hydrostatic pressure. Saphenous vein grafts (SVGs) diverge in origin and trajectory from native coronary arteries, which may increase the susceptibility of fractional flow reserve (FFR) measurements to be impacted by the hydrostatic pressures. The precise impact of SVG anatomy on physiological pressure indices remains unknown at present. Purpose We sought to study the impact of SVG anatomy on FFR. Methods Included were symptomatic patients with prior coronary artery bypass grafting and at least one non-occluded SVG, who underwent coronary computed tomography angiography (CCTA) preceding invasive coronary angiography. SVG course and height excursion were reconstructed based on the CCTA images. Similarly to native coronary arteries, the impact of hydrostatic pressure on FFR was calculated by adding 0.077 mmHg to the distal coronary pressure for every millimeter height difference in a supine position between the SVG ostium and the position of the pressure wire tip. Results In total, 74 patients (mean age 71 ± 7 years; 85% male) with 87 SVGs were included. A total of 76 SVGs underwent interrogation by FFR. The height difference between SVG ostium and pressure wire tip position was largest for single SVGs to the circumflex artery (Cx; - 55.1 ± 17.0 mm), followed by sequential SVGs to the Cx (- 53.1 ± 17.7 mm) and to the right coronary artery (RCA; - 36.7 ± 21.6 mm). Corrected FFR was significantly lower as compared to uncorrected FFR in single SVGs to the Cx (0.85 ± 0.17 vs. 0.90 ± 0.18), and sequential SVGs to the Cx (0.92 ± 0.14 vs. 0.96 ± 0.15) and the RCA (0.82 ± 0.20 vs. 0.85 ± 0.21) (P<0.001 for all). Conclusions Hydrostatic pressure related to the course anatomy of SVGs notably affects FFR values, resulting in an overestimation of FFR in SVGs to the Cx and sequential SVGs to the RCA. In these SVGs, FFR values near the cutoff value should be interpreted cautiously.

Initial results of the READY registry: comparison of visual and physiological lesion characterization and the effect of hydrostatic pressure correction

Abstract We aimed to compare resting Pd/Pa, FFR, and distal RFR values with and without hydrostatic pressure correction. Our main goal was to assess the influence of this correction on cut-off value-based decision-making for each physiological parameter. Data from patients enrolled in two centers of the READY registry (NCT04857762) were analyzed. Center 1 employed catheter and pressure sensor height differences defined from lateral angiographic projection for hydrostatic pressure correction, while Center 2 utilized average pressure differentials from published data. In Center 1, the height difference underlying the hydrostatic pressure correction did not differ significantly from the average values published in previous publication (-5.22±1.1cm for LAD, 2.44±1.1cm for CX, and 1.63±2.8cm for RCA). Consequently, FFR and distal RFR values corrected with average pressure differentials rarely yielded different cut-off-based characterizations compared to individually measured corrections (2.4%). A total of 42 measurements were evaluated in Center 1 (33 patients) and 40 measurements in Center 2 (40 patients). Stenoses were characterized using resting Pd/Pa (0.91 ± 0.05), FFR (0.80 ± 0.08), distal RFR (0.86 ± 0.09) and ΔRFR (0.07 ± 0.07) values. Regarding all the investigated vessels, statistically significant differences were observed in FFR (0.80 ± 0.08 vs 0.81 ± 0.08; p < 0.001), distal RFR (0.86 ± 0.09 vs 0.87 ± 0.09; p < 0.001), and ΔRFR (0.053 ± 0.04 vs 0.047 ± 0.04; p = 0.014) before and after correction. These changes after hydrostatic correction were driven dominantly by the LAD measurements being LAD stenoses constituted the majority of the cases (73.2%). Overall (n=82), hydrostatic pressure correction modified cut-off-based categorization in 24 (29.3%) cases for Pd/Pa, and 19 (23.2%) cases for both distal RFR and FFR measurements. Notably, ΔRFR assessment also changed in 22.2% of cases after correction. Among LAD stenoses (n=60), hydrostatic pressure correction altered cut-off-based characterization in 22 (36.7%), 19 (31.7%), and 17 (28.3%) cases of resting Pd/Pa, distal RFR, and FFR measurements, respectively. Hydrostatic pressure correction offers the potential to enhance the accuracy of intracoronary physiological measurements, especially for LAD stenoses. Our data suggest that the published average pressure differences of each coronary segment can be used for correction.Lateral view and delta RFRIndividual vs Average LAd correction

Adolescent social stress alters the role of orexin innervation in the hindbrain in male hamsters.

Juvenile male hamsters exposed to chronic social stress eat more, gain weight, and have larger fat pads. The purpose of the present study was to address possible changes in food hoarding and orexin/hypocretin innervation in response to social stress. Male hamsters in early adolescence were exposed to a resident-intruder social stress paradigm or control condition daily for 2 weeks. Metabolism-related physiological measures and behaviors were tracked, and brains were immunocytochemically labeled for orexin-A. Our data confirm our previous observations on appetite, weight gain, and obesity, and showed a strong trend toward enhanced food hoarding as in prior studies. In addition, there were no statistically significant differences in orexin innervation in any brain area analyzed. However, unique correlation patterns were observed between orexin innervation and appetite or metabolic outcome. In particular, opposite correlations were observed between groups within the dorsal raphe nucleus, lateral parabrachial nucleus, and nucleus of the solitary tract. These opposite patterns of correlations suggest chronic social stress causes site-specific alterations in synaptic activity in relation with these behaviors.

Enhancing Sleep and Reducing Occupational Stress Through Forest Therapy: A Comparative Study Across Job Groups.

The coronavirus disease-2019 (COVID-19) pandemic radically shifted occupational patterns, leading to increased telecommuting and related stressors. Healthcare providers, among the most impacted group, faced heightened risks and workplace changes. Our study examined the efficacy of forest therapy in alleviating work-induced stress across various professions, exploring the need for profession-specific stress-relief strategies in the post-pandemic workplace. To examine the impact of COVID-19 on professionals, 62 participants were recruited, consisting of 20 healthcare providers, 21 information technology (IT) specialists, and 21 teachers. Instruments such as Pittsburgh Sleep Quality Index and Hospital Anxiety and Depression Scale, along with salivary tests for cortisol and melatonin, were used to assess the participants' sleep and stress levels. A specialized forest healing program was implemented among these participants. Data analysis was conducted using SPSS Win Ver. 22.0, utilizing paired t-tests and a repeated measures analysis of variance. Significant improvements were observed in the participants' sleep metrics, depression scales, and stress levels after the forest healing program. Physiological measures indicated an increase in melatonin and a decline in cortisol and dehydroepiandrosterone sulfate levels, with only cortisol changes being statistically significant. Teachers, participating during school vacations, exhibited minimal stress-related physiological changes. Overall, the program demonstrated widespread health benefits regardless of occupation or gender. This study showed that forest therapy reduced stress equally across professions, including healthcare providers, IT specialists, and teachers. Individual physiological responses may play a greater role in stress relief than the specific occupation.

Assessment of Abuse Liability and Nicotine Pharmacokinetics of glo Heated Tobacco Products in a Randomized, Crossover Study.

Heated tobacco products (HTPs) are a class of non-combustible, inhaled tobacco products with the potential to reduce the harm associated with cigarette smoking due to reduced cigarette smoke toxicant exposure. Subjective and nicotine pharmacokinetics measures taken over the course of product use provide a framework for abuse liability (AL) assessment of tobacco and nicotine products as well as information on adoption potential for a new tobacco product, which are important aspects for premarket tobacco product authorization by the US Food and Drug Administration. This study aimed to assess the AL of glo HTPs, operated in either Standard or Boost Modes, compared with high- and low-AL comparators (subjects' usual brand cigarettes and nicotine gum, respectively). Nicotine uptake and pharmacodynamics measures (including subjective and physiological measures) were assessed in a clinical study of 75 healthy adult non-menthol or menthol smokers using an open-label, randomized crossover study design. Comparisons were made between glo HTPs (Standard or Boost Modes) and each of usual brand (UB) cigarettes and nicotine gum to evaluate nicotine exposure and subjective effects measures. Nicotine uptake, as reflected in the area under the curve (AUC) at 15 and 240 min after product use (AUC0-15 and AUC0-240, respectively) and maximum nicotine concentration (Cmax) were significantly lower for all glo HTPs compared to UB cigarettes, regardless of the glo device mode. AUC0-15 values for glo HTPs ranged from 41.26 to 75.71 ng × min/mL, versus 158.04 to 165.53 ng × min/mL for UB cigarettes. Similarly, AUC0-240 values for glo HTPs ranged from 379 to 596 ng × min/mL, compared to 1123.73 and 1283.37 ng × min/mL for UB cigarettes. The Cmax for glo HTPs ranged from 5.46 to 9.00 ng/mL, whereas UB cigarettes had Cmax values of 16.29 to 16.76 ng/mL. The time to reach maximum nicotine concentration (Tmax) was significantly shorter for glo HTPs (4-5 min) compared to UB cigarettes (6-7 min), except for one variant of glo HTP in Standard Mode. Nicotine gum exhibited a slower nicotine absorption profile, with a Tmax of 45 min and Cmax of 4.60 ng/mL. AUC0-15 and AUC0-240 values for nicotine gum were 6.18 and 5.22 ng × min/mL, and 647.80 and 687.68 ng × min/mL for non-menthol and menthol groups, respectively. Subjective measures indicated that glo HTPs were rated significantly lower than UB cigarettes in terms of product liking, smoking urge reduction, product effects, and intent to use again, but were comparable to nicotine gum. glo HTPs demonstrated lower AL than combustible cigarettes while delivering sufficient nicotine to support product adoption among current smokers. This positions glo HTPs as a potential tool in tobacco harm reduction, offering a less harmful alternative to traditional cigarettes. Clinical trial ID NCT05114863.

Affective Engagement with Metaphor in Introductory Statistics Education

Metaphor is a popular pedagogical tool to help learners understand unfamiliar concepts, but its affective and interactional qualities remain underexplored compared to its cognitive benefits. This study investigates how metaphor may enhance affective engagement within introductory statistics education for linguistics students. As previous research tends to rely on delayed and self-reported data, this study employs a mixed-methods approach that combines real-time physiological measures of engagement with feedback through surveys and interviews. It compares metaphorical and literal instructional styles for teaching simple linear regression, focusing on: i) differences in teacher and learner skin conductance levels, ii) teacher-learner synchrony through skin conductance concordance, iii) the relationship between physiological measures and affect-related survey responses, and iv) learner reflections on their experiences. Results show that the metaphorical style is associated with higher engagement levels and stronger teacher-learner synchrony, affirming the role of metaphors in enhancing collaborative learning when elaborated over time in spontaneous interactive fashion. However, the qualitative data reveal nuanced learner perceptions, highlighting the importance of clearly communicating the scope of metaphor use. This study contributes to understanding the interplay between affective and cognitive engagement in metaphorical learning, offering practical recommendations for its effective implementation in complex subjects like statistics.

Shifts in task absorption during decision-making episodes

In today’s rapidly evolving technological landscape, this study investigates the impact of new technology on organizational work dynamics. By integrating the Job Demands-Resources theory and the Episodic Process Model, we examine the cognitive mechanisms that influence task performance during decision-making episodes. Our research focuses on episodic job demands and resources, emphasizing the mediating role of task absorption in the relationship between these factors and task performance. Our findings reveal that episodic job resources positively affect task absorption and performance, while job demands moderate the relationship between job resources and task absorption. Employing the Beer Distribution Game alongside neuroscience-based eye-tracking techniques, we analyze visual attention dynamics during decision-making episodes, providing novel insights into the interplay between task absorption and task performance. Theoretically, our study highlights the significance of task absorption in understanding how episodic job resources impact decision-making performance. Practically, our results advocate for the implementation of decision-making-focused skills development through physiological measures such as neurofeedback training programs. This research underscores the importance of individual time management in enhancing task performance, contributing to a nuanced understanding of job resources, job demands, and task absorption in the context of technological transformation.

Feasibility of Using Wearable Sensors to Measure Listening-Related Stress

Purpose: This study evaluated the feasibility of using wearable sensors to assess listening-related stress in varying listening difficulties. The results were compared to listening effort assessed using laboratory-grade physiological measures. We hypothesized that these wearable sensors could accurately measure listening-related stress and that the results would be in the same direction as those observed with laboratory-grade equipment. Method: A within-subject repeated-measures study was conducted on 16 young adults with typical hearing ability. Participants wore three commercially available sensors to record heart rate (HR), respiration rate (RR), and galvanic skin response (GSR). Participants' listening-related stress was assessed using self-report, wearable sensors, and laboratory-grade physiological measures while listening to sentences in noise. Listening conditions were manipulated in terms of signal-to-noise ratios (SNRs; −4, 0, +4, and +8 dB SNR), sentence predictability (high and low), and stress-inducing negative feedback (flash of light and monetary punishers). Results: On average, participants reported higher arousal and task load with decreasing SNR, for low predictability, and with negative feedback. Participants had significantly higher HR and RR in difficult listening conditions, when measured with wearable sensors. However, no significant differences were observed for skin conductance. There was a good agreement between the measures for HR but not for RR and GSR. Conclusions: Although wearable sensors have potential in reflecting changes in listening effort, the results were not consistent with laboratory-grade measures. Methodological choices in both measures and design appear to affect outcomes. Future studies should focus on crafting designs appropriate to wearable devices to reflect changes in listening-related stress.

Measuring and Explaining Situational Fear of Crime: An Experimental Study Into the Effects of Disorder, Using Virtual Reality and Multimodal Measurement

Abstract The current study combines an experimental research design, Virtual Reality (VR) and multimodal (survey and physiological) measurements to measure and explain situational fear of crime. 159 participants completed our VR experiment in which we focused on the role of physical and social disorder in engendering situational fear of crime. Drawing on our survey measures, we find significant effects of disorder on a variety of outcome variables: situationally experienced safety, fear of theft, fear of verbal aggression, fear and physical aggression and fear of sexually transgressive behaviour. Most of our physiological measures rendered null findings. Hence, we also conclude that the results from our two data sources (survey measures vs. physiological measures) diverge in important ways.

Integrated physiological and transcriptome analyses of the effects of water-soluble amino acid fertilizer on plant growth

Tobacco is a key component of China’s economy, serving as a major cash crop. With traditional fertilizers reaching their maximum potential in promoting tobacco growth, the exploration of new fertilizers has emerged as a viable solution for advancing experimental sustainable development. Spraying foliar fertilizer is a key measure to improve tobacco yield and quality. This study employed a combination of field and pot experiments to investigate the effects of applying water-soluble amino acid fertilizers on the growth, development, and quality of tobacco. The results of transcriptome analysis and physiological index measurements indicate that the application of water-soluble amino acid fertilizer can enhance the area of tobacco leaves, promote photosynthesis, and improve the chemical composition of the leaves. This research determined that the optimal concentration for spraying water-soluble amino acid fertilizer is diluted 500 times. Transcriptome analysis identified a total of 6,489 differentially expressed genes (DEGs), including 3,843 genes that were up-regulated and 2,646 genes that were down-regulated. Gene Ontology (GO)analysis demonstrated that these DEGs were significantlyassociatedwithprocessesincludingcell recognition, photosynthesis,thylakoidcomponents, calcium ion binding, and carbohydrate binding.Additionally, Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis emphasized that the DEGs were largely found in pathwaysrelated tophotosynthesis-antenna proteins, interactions between plants and pathogens, photosynthesisitself, phenylpropanoid biosynthesis, andplant hormone signaling. Further research revealed that a significant number of genes involved in the auxin, gibberellin, salicylic acid, and jasmonic acid signal transduction pathways exhibited varying expression patterns following the application of water-soluble amino acid fertilizers.Additionally, the expression levels of bZIP, MYB, WRKY, bHLH, and AP2/ERF transcription factors exhibited significant variations following the application of water-soluble amino acid fertilizer. These results analyze the mechanisms of action of water-soluble amino acid fertilizers, offering new effective strategies to enhance both the yield and quality of tobacco.

Neurophysiological approaches to exploring emotional responses to cosmetics: a systematic review of the literature.

This systematic review explores the use of neurophysiological measurements to study emotional responses to cosmetic products. The aim is to evaluate existing literature on these measurements in cosmetics, identify the main findings, highlight methodological challenges, and propose new guidelines for future research. A systematic search focusing on neurophysiological measures to determine emotions induced by different cosmetic products was carried out in accordance with PRISMA guidelines. A total of 33 articles identified with the EBSCO database met the inclusion criteria. In all, 10 different measurement tools were used in these articles to assess the emotional effects of cosmetic products. This review emphasizes the complexity of interactions between cosmetics and emotional responses. It underscores the importance of future research with a more holistic approach that couples several physiological measurements. Among them, electrophysiological brain activity shows potential for enhancing understanding of emotional responses related to cosmetic products. Frontal asymmetry, particularly in the alpha frequency band, was often use and frequently linked to positive emotional states, although conflicting evidence exists. Additionally, cardiac activity, specifically the LF/HF ratio, emerges as a promising marker for differentiating between different cosmetic products. However, methodological heterogeneity, present challenges for replicability, generalizability, and complicate data interpretation.

Catching Mind Wandering With Pupillometry: Conceptual and Methodological Challenges.

Mind-wandering (MW) refers to the shift of attention away from an ongoing task and/or external environment towards mental contents (e.g., memories, prospective thoughts) unrelated to the task. Physiological measures (e.g., pupil size, EEG, and fMRI) have often been acquired as objective markers for MW states, which has greatly helped their study as well as triangulation with other measures. Pupillometry in particular has been used as a covert biomarker of MW because it is reliably modulated by several distinct processes spanning arousal, emotion, and attention, and it signals attentional lapses. Yet, coupling MW and the measurement of pupil size has led to seemingly contrasting results. We argue that, common to the studies reviewed here, one reason is resolving to the measurement of tonic pupil size, which reflects low-frequency, slow changes in one's physiological state, and thus implicitly assumes that MW is a static, long-lasting process. We then additionally focus on three major axes of variability in the reviewed studies: (i) the definition and measurement of MW; (ii) the impact of contextual aspects, such as task demands and individual arousal levels; (iii) the identification and tracking of MW in combination with pupillary measures. We provide an overview of these differences and put forward recommendations for using physiological measures-including, but not limited to, pupil size-in MW research effectively. In conclusion, pupillometry can be a very informative tool for MW research, provided that it is used with the due methodological caution.

A classification system for identifying persons with an unknown cardiovascular disease (CVD) status for a multiracial/ ethnic Caribbean population.

The need for classification systems for cardiovascular disease (CVD) that is population-specific is important towards understanding the clinical disease and diagnostics associated with the disease. This paper presents the form and validation results of this classification system. The survey data used was captured from 778 participants, 526 persons with no prior CVD, and 252 who reported prior CVD. Binomial logistic regression and Discriminant analysis were utilised to develop classification models. This classification system provided a general measure of severity of disease by utilising scores estimated from two algorithms developed from 13 routine physiologic measurements, along with demographic information of age and ethnicity, inter alia, and previous health status. For each model, specific score ranges were identified, which gave the best classification for those with a prior CVD incident (higher scores) and for others labelled as non-CVD (lower scores). The two classification models (Logistic Regression Model and Discriminant Analysis Model) developed had high area under the receiver-operating characteristic (AUROC) values (98% & 99%) and sensitivity (86 and 90%), which improved discrimination between Non-CVD and CVD participants and, more importantly, correctly classified a greater proportion of CVD participants. New to this type of research was the estimation and detailed evaluation of a range of scores, labelled non-differentiating, which fell in the middle of the spectrum and which contained the higher-end scores for the non-CVD individuals and the lower-end scores for CVD patients, all of whom were incorrectly classified, based on their prior history. The classification system of scores is able to differentiate the CVD status of individuals, with good predictability, and could assist physicians with recommending different treatment plans. The two models in this classification system each individually outperformed the three established models in terms of the strength of their correct classifications of individuals with or without prior reported CVD incidents. More importantly, they have smaller non-differentiating ranges than the three known models and, in that range, the two new models have lower CVD/non-CVD ratios suggesting they are more likely to misclassify non-CVD individuals compared to CVD patients, which is a more benign misclassification. Further, when used in combination, the two models increased the sensitivity, in classifying individuals of different ethnicities, beyond that of either one used independently or of any of the three standard European/North American models. These efforts will be instrumental in advancing personalised CVD management strategies and improving health outcomes across diverse populations.

Analysis of Mental Workload in Appropriate Technology (AT) for Agricultural Machinery Using Heart Rate Variability (HRV) Parameters

Appropriate Technology (AT) is designed to substitute manual work and to increase productivity for small-medium businesses. Due to its low-cost technology that affects its design quality, the acceptance of AT appears to be low. A guideline has yet to be available to determine AT's design quality. The purpose of this study was to explore the efficacy of physiological measures collected from a Heart Rate Monitor (HRM) in differentiating mental workload in using AT. If applicable, these measures can provide objective data for AT evaluation. Several parameters were collected from HRM, including frequency domain and time domain. Two ATs were used for evaluation that represented “good” and “poor” agricultural processing machines. Eleven participants were involved in this study in which they used both ATs. The result of this studyis the ratio of Low Frequency and High Frequency (LF/HF) parameter detects differences perceived by the participants. The increase in the LF/HF value from the Commercial Extruder to the Customized Extruder is directly proportional to the increase in mental workload, where the Commercial Extruder is defined as a “good” AT design, and the Customized Extruder as a “poor” AT design. Therefore, it can be concluded that designs with specific guidelines can reduce the mental workload perceived by operators.

Higher oxygen content and transport characterize high-altitude ethnic Tibetan women with the highest lifetime reproductive success

We chose the "natural laboratory" provided by high-altitude native ethnic Tibetan women who had completed childbearing to examine the hypothesis that multiple oxygen delivery traits were associated with lifetime reproductive success and had genomic associations. Four hundred seventeen (417) women aged 46 to 86 y residing at ≥3,500 m in Upper Mustang, Nepal, provided information on reproductive histories, sociocultural factors, physiological measurements, and DNA samples for this observational cohort study. Simultaneously assessing multiple traits identified combinations associated with lifetime reproductive success measured as the number of livebirths. Women with the most livebirths had distinctive hematological and cardiovascular traits. A hemoglobin concentration near the sample mode and a high percent of oxygen saturation of hemoglobin raised arterial oxygen concentration without risking elevated blood viscosity. We propose ongoing stabilizing selection on hemoglobin concentration because extreme values predicted fewer livebirths and directional selection favoring higher oxygen saturation because higher values had more predicted livebirths. EPAS1, an oxygen homeostasis locus with strong signals of positive natural selection and a high frequency of variants occurring only among populations indigenous to the Tibetan Plateau, associated with hemoglobin concentration. High blood flow into the lungs, wide left ventricles, and low hypoxic heart rate responses aided effective convective oxygen transport to tissues. Women with physiologies closer to unstressed, low altitude values had the highest lifetime reproductive success. This example of ethnic Tibetan women residing at high altitudes in Nepal links reproductive fitness with trait combinations increasing oxygen delivery under severe hypoxic stress and demonstrates ongoing natural selection.

Optimal Instruments for Measurement of Dietary Intake, Physical Activity, and Sleep Among Adults in Population-Based Studies: Report of a National Heart, Lung, and Blood Institute Workshop.

The National Heart, Lung, and Blood Institute convened a virtual workshop in September 2022 to discuss "Optimal Instruments for Measurement of Diet, Physical Activity, and Sleep." This report summarizes the proceedings, identifying current research gaps and future directions for measuring different lifestyle behaviors in adult population-based studies. Key discussions centered on integrating report-based methods, like questionnaires, with device-based assessments, including wearables and physiological measures such as biomarkers and omics to enhance self-reported metrics and better understand the underlying biologic mechanisms of chronic diseases. Emphasis was placed on the need for data harmonization, including the adoption of standard terminology, reproducible metrics, and accessible raw data, to enhance the analysis through artificial intelligence and machine learning techniques. The workshop highlighted the importance of standardizing procedures for integrated behavioral phenotypes using time-series data. These efforts aim to refine data accuracy and comparability across studies and populations, thereby advancing our understanding of lifestyle behaviors and their impact on chronic disease outcomes over the life course.

Digital phenotyping from wearables using AI characterizes psychiatric disorders and identifies genetic associations.

Psychiatric disorders are complex and influenced by both genetic and environmental factors. However, studying the full spectrum of these disorders is hindered by practical limitations on measuring human behavior. This highlights the need for novel technologies that can measure behavioral changes at an intermediate level between diagnosis and genotype. Wearable devices are a promising tool in precision medicine, since they can record physiological measurements over time in response to environmental stimuli and do so at low cost and minimal invasiveness. Here we analyzed wearable and genetic data from a cohort of the Adolescent Brain Cognitive Development study. We generated >250 wearable-derived features and used them as intermediate phenotypes in an interpretable AI modeling framework to assign risk scores and classify adolescents with psychiatric disorders. Our model identifies key physiological processes and leverages their temporal patterns to achieve a higher performance than has been previously possible. To investigate how these physiological processes relate to the underlying genetic architecture of psychiatric disorders, we also utilized these intermediate phenotypes in univariate and multivariate GWAS. We identified a total of 29 significant genetic loci and 52 psychiatric-associated genes, including ELFN1 and ADORA3. These results show that wearable-derived continuous features enable a more precise representation of psychiatric disorders and exhibit greater detection power compared to categorical diagnostic labels. In summary, we demonstrate how consumer wearable technology can facilitate dimensional approaches in precision psychiatry and uncover etiological linkages between behavior and genetics.

In vivo imaging of the human brain with the Iseult 11.7-T MRI scanner.

The understanding of the human brain is one of the main scientific challenges of the twenty-first century. In the early 2000s, the French Atomic Energy Commission launched a program to conceive and build a human magnetic resonance imaging scanner operating at 11.7 T. We have now acquired human brain images in vivo at such a magnetic field. We deployed parallel transmission tools to mitigate the radiofrequency field inhomogeneity problem and tame the specific absorption rate. The safety of human imaging at such high field strength was demonstrated using physiological, vestibular, behavioral and genotoxicity measurements on the imaged volunteers. Our technology yields T2 and T2*-weighted images reaching mesoscale resolutions within short acquisition times and with a high signal and contrast-to-noise ratio.

EzySCR: A free and easy tool for scoring event-related skin conductance responses in the first, second, and third interval latency windows.

Skin conductance is a commonly used physiological measure during psychology experiments, such as during fear conditioning. Methods for scoring skin conductance responses (SCRs) are highly heterogeneous, though most researchers agree that manually inspected scores provide the highest quality data when compared to most available fully automated scoring methods. However, manual scoring is extremely time-consuming. We developed a semi-automated scoring program that reduces the time required to process SCR data at a level of quality akin to manual scoring. In contrast to all previous scoring programs, our program enables scoring of first interval response (FIR), second interval response (SIR), and third interval response (TIR) SCRs. Using interclass correlation coefficients (ICCs), Bland-Altman plots and Pareto analysis, we show here that our method is highly reliable and produces data that are almost identical to data that are manually scored and scored using LEDALAB. This software is very easy to use and is freely available to download and modify. We expect that this software will be helpful in reducing the time required to produce high quality FIR, SIR, and TIR skin conductance data for psychology researchers around the world.