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Emerging research suggests that the gut microbiome plays a crucial role in stress. We assess stress-microbiome associations in two samples of healthy adults across three stress domains (perceived stress, stressful life events, and biological stress /Respiratory Sinus Arrhythmia; RSA). Study 1 (n = 62; mean-age = 37.3 years; 68% female) and Study 2 (n = 74; mean-age = 41.6 years; female only) measured RSA during laboratory stressors and used 16S rRNA pyrosequencing to classify gut microbial composition from fecal samples. Phylogenetic Investigation of Communities by Reconstruction of Unobserved States was used to predict functional pathways of metagenomes. Results showed differences in beta diversity between high and low stressful life events groups across both studies. Study 1 revealed differences in beta diversity between high and low RSA groups. In Study 1, the low perceived stress group was higher in alpha diversity than the high perceived stress group. Levels of Clostridium were negatively associated with RSA in Study 1 and levels Escherichia/Shigella were positively associated with perceived stress in Study 2. Associations between microbial functional pathways (L-lysine production and formaldehyde absorption) and RSA are discussed. Findings suggest that certain features of the gut microbiome are differentially associated with each stress domain. [ABSTRACT FROM AUTHOR]

Background Methods Results Conclusions Family environment plays a critical role in shaping stress response systems. Concordance between mothers' and children's physiological states, specifically their Respiratory Sinus Arrhythmia (RSA), reflects dyadic co‐regulation. Negative or weakened RSA synchrony during interactions is linked to various psychosocial risks, but existing research has focused on risks in the mother or child as opposed to the dyad. This study examined the association between maternal‐child RSA synchrony and maternal ACEs, given documented associations with offspring RSA, as well as more proximal documented risks, including maternal psychopathology and children's early adversity and psychopathology. Given that sensitive parent–child relationships are a powerful source of resilience, we tested whether parent–child relationship quality buffered associations between maternal ACEs and RSA synchrony.In a community sample of mother–child dyads experiencing high sociodemographic risk and oversampled for exposure to adversity, mothers (n = 123) reported on their ACEs (43.1% ≥4), their 3–5‐year‐old children's exposure to violence, and psychological symptoms. Dyads completed a puzzle task while EKG was recorded, from which maternal and child RSA was derived; parent–child relationship quality during interactions was coded observationally. Multilevel models examined within‐dyad mother–child RSA synchrony across the interaction and between‐dyad predictors of synchrony.Parent–child relationship quality and maternal ACEs co‐contributed to offspring and dyadic physiology. Maternal ACEs predicted dampened RSA in the child and dampened RSA synchrony in the dyad, only among dyads with low observer‐rated parent–child relationship quality during the interaction. In other words, high‐quality parent–child relationship quality buffered the association between maternal ACEs and dampened offspring and dyadic physiology.Results suggest that mothers' early adversity may disrupt physiological regulation at both the individual child and dyadic level. High‐quality parent–child relationships mitigated this effect. [ABSTRACT FROM AUTHOR]

ABSTRACT Introduction Methods Results Conclusions Recent evidence suggests that autonomic nervous system functioning can reflect individual differences in sensitivity to the environment, which in turn moderates the effects of family context on psychopathic and antisocial behaviour. Although some preliminary research suggests that the coordination of the sympathetic (SNS) and parasympathetic (PNS) branches of the autonomic nervous system may reflect sensitivity to environmental influences, the majority of research to date has been limited in its focus on just one branch, and little is known about the effects of parental empathy on a child's psychopathic‐like traits. This study aimed to address this gap by examining if the SNS and PNS jointly moderate the prospective contribution of parental empathy to youth psychopathic‐like traits.Male and female children (n = 340; age = 8–10 years) from the community completed an emotion regulation task during which their skin conductance level (SCL) and respiratory sinus arrhythmia (RSA) activity were recorded. Parental cognitive, affective, and somatic empathy were reported by the caregivers. The child's psychopathic‐like traits were reported by the caregiver and the child and were reassessed 1 year later.Hierarchical regression indicated that after controlling for child sex, age, and concurrent CU traits, low affective empathy in parents predicted higher CU traits 1 year later in youths who exhibited reciprocal sympathetic activation (i.e., SNS activation along with PNS withdrawal), reflecting their enhanced sensitivity to the environment. No such effects were found for other psychopathic‐like traits.Findings suggest that reciprocal SNS reactivity may be a biological indicator for sensitivity to environmental influence and highlight the importance of examining the interactions among multiple systems to better understand the aetiology of psychopathic traits. [ABSTRACT FROM AUTHOR]

ABSTRACT Nutrition and the home environment contribute to the development of the autonomic nervous system (ANS). However, no study has examined the long‐term effects of prenatal and postnatal small‐quantity lipid‐based nutrient supplements (SQ‐LNS) and home environment on ANS regulation. We investigated the effect of early‐life SQ‐LNS and home environment on ANS regulation at 9–11 years. Participants were children born to women who participated in a randomized controlled trial in Ghana from 2009 to 2014. Women were randomized to receive daily, from pregnancy until delivery, either SQ‐LNS, multiple micronutrients (MMN) or iron and folic acid (IFA) followed by SQ‐LNS, MMN or placebo, respectively, until 6 months postpartum. Infants in the SQ‐LNS group received SQ‐LNS from 6 to 18 months. Quality of home environment was observed at 4–6 and 9–11 years. At 9–11 years, 965 children had their respiratory sinus arrhythmia (RSA) and pre‐ejection period (PEP) measured at baseline and during two inhibitory control tasks, the RACER Simon and Emotion Go/No‐Go (EGNG) tasks. PEP reactivity to the RACER Simon task was greater in the MMN (−2.54 ± 4.45, p = 0.016) and SQ‐LNS (−2.31 ± 4.94, p = 0.093) groups than in the IFA group (−1.57 ± 3.51). A better home environment at 4–6 predicted longer baseline PEP (β = 0.13, 95% CI: 0.02, 0.23, p = 0.016) and more PEP reactivity during the EGNG task (β = −0.06, 95% CI: −0.00, −0.02, p = 0.001). Prenatal micronutrient supplementation appears to increase SNS reactivity. Children raised in disadvantaged early home environments had more tonic SNS activation and less SNS reactivity, suggesting a predisposition for stronger fight‐or‐flight activation and less likelihood to modulate arousal in response to acute situations.Trial Registration: ClinicalTrials.gov identifier: NCT00970866 [ABSTRACT FROM AUTHOR]

Panic disorder (PD) may accompany elevated social avoidance and distress (SAD). Higher SAD in patients with PD predicts a poorer prognosis and response to treatment. As heart rate variability (HRV) reflects the self‐regulatory capacity underlying SAD, applying HRV to distinguish PD heterogeneity would be clinically beneficial in formulating personalized treatment strategies. We hypothesized that HRV would be lower in patients with PD and severe SAD (PD‐SAD group) than in those without SAD (PD group). A total of 288 patients met the eligibility criteria, with complete collection of variables of interest and HRV. The inverse probability of treatment weighting (IPTW) method was used to balance the groups for the baseline characteristics of patients. Following IPTW adjustment, the average treatment effects were computed using inverse propensity weighting with regression adjustment (IPW‐RA). All characteristics were similar in both groups after IPTW adjustment. The PD‐SAD group showed a decreased tendency in time domain parameters, including mean heart rate, SDNN, RMSSD, and pNN50 with a nonlinear domain of SD1. However, no significant intergroup differences were observed in the frequency domain. Higher SAD in PD was associated with reduced HRV, mainly in the time domain, which may be attributed to the shared neural networks between dysfunctional self‐regulation statuses, as indexed by reduced HRV. As respiratory sinus arrhythmia is mainly reflected in the frequency domain, the time domain may be more reliable for identifying heterogeneity within patients with PD, who are frequently associated with respiratory pattern abnormalities. [ABSTRACT FROM AUTHOR]

Children with specific psychophysiological profiles may be more strongly affected by adverse environmental experiences. Guided by a biopsychosocial perspective, we examined whether infant respiratory sinus arrhythmia (RSA), an index of parasympathetic functioning, moderates the associations between paternal postpartum depression (PPD) symptoms and infants' observed empathy‐related responses. Participants were 142 families with infants (51% female) assessed at two time points. At T1 (3 months of age), fathers reported their depressive symptoms. Infants' cardiac activity was recorded during rest and estimates of RSA were calculated. In addition, infants' empathy‐related responses during a maternal distress simulation were observed and rated at T2 (12 months of age). Higher paternal PPD at T1 predicted higher infant affective (i.e., affective concern) and cognitive (i.e., inquiring behaviors) responses to maternal distress at T2. Infant RSA moderated this relationship for cognitive responses, with a significant positive association only for children with high or average RSA. These findings contribute to the understanding of the psychophysiological mechanisms that support empathy development. [ABSTRACT FROM AUTHOR]

During an ECG-training course, a case of extreme respiratory sinus arrhythmia (RSA) was found in a 19-year-old slender, female student who was not active in sports. The heart rate (HR) fluctuated from above 100 to below 60 beats per minute (bpm), often from one beat to the next. The pattern was repetitive and appeared to be linked to respiration, representing an extreme form of RSA. The initial recording of the HR and blood pressure (BP) by finger blood pressure showed concomitant drops in diastolic BP of up to 25 mmHg. The student agreed to participate in a short follow-up study, during which HR, BP, and respiration (measured by temperature and pCO2 of the airflow at the nose) were recorded in the supine and upright tilted positions. Measurements were taken during 5 min of rest, during paced breathing (1 min each at 6, 10, and 15 breaths per min), and during end-expiratory breath-hold. This study presents a beat-by-beat analysis of the observed interrelations between respiration, HR, and BP. Her respiratory rate with maximal RSA was found to be only slightly lower than the spontaneous rate, at 10 versus 12 breaths per min. From the combined observations, it was concluded that, in this case, the baroreflex relationship between spontaneous BP and HR changes was overridden by near on/off gating of (possibly massive) cardiac vagal outflow. This is due to a central, respiration-coupled gating mechanism, with the vagus nerve being "on" during expiration and "off" during inspiration. Such a system will destabilize blood pressure. It shows an evolutionary remnant of optimizing lung perfusion during air inflation, regardless of the consequences for systemic blood pressure. [ABSTRACT FROM AUTHOR]

Depression and alcohol use are highly comorbid, and often emerge during adolescence. Depressive symptoms may precede alcohol use, via the self-medication pathway, or alcohol use may precede depressive symptoms, via the alcohol induced disruption pathway. Yet little is known about other risks for developing comorbidity via either path. The present study hypothesized that poor cognitive and physiological emotion regulation (ER) are risk factors implicated in the development of comorbid depression and alcohol use during late adolescence. Participants were 229 (113 girls) Mexican-origin youth who reported on depressive symptoms and alcohol use at ages 17 (Time 1) and 19 years (Time 2). At age 17, cognitive reappraisal (CR), an adaptive ER strategy, and baseline respiratory sinus arrhythmia (RSA), a physiological index of ER capacity, were assessed. CR, RSA and gender were examined as predictors and moderators of the developing comorbidity of alcohol use and depression in cross-lagged panel models. Lower use of CR was concurrently associated with more depressive symptoms at age 17 and predicted greater depression at age 19. Age 17 alcohol use predicted age 19 depressive symptoms for boys. Lower RSA at age 17 also predicted more depressive symptoms at age 19 for boys. Neither CR nor RSA moderated the predicted relations between depression and alcohol use. Findings supported the alcohol induced disruption model of comorbidity for boys, and showed that poor cognitive and physiological ER increased risk for exacerbating depressive symptoms in late adolescence. [ABSTRACT FROM AUTHOR]

Child maltreatment is associated with respiratory sinus arrhythmia (RSA) dysregulation, a physiological indicator of emotion regulation that predicts elevated posttraumatic stress disorder (PTSD) symptoms and may be a mechanism of action for exposure‐based therapies, such as trauma‐focused cognitive behavioral therapy (TF‐CBT). Animal‐assisted therapy (AAT) has been proposed as an adjunct to TF‐CBT for improving emotion regulation following maltreatment. The current study reports findings from a randomized controlled feasibility trial (N = 33; Mage = 11.79 years, SD = 3.08; 63.6% White; 66.7% female) that measured youths' resting RSA, RSA reactivity, and RSA recovery in response to a pretreatment laboratory challenge. We tested whether (a) lower pretreatment resting RSA was associated with blunted RSA during the challenge; (b) either of the pretreatment RSA dimensions predicted more severe pretreatment PTSD symptoms; and (c) either of the pretreatment RSA dimensions predicted less severe posttreatment PTSD symptoms and, as an exploratory aim, whether this was moderated by treatment group (i.e., TF‐CBT vs. TF‐CBT + AAT). Results from multiple linear regression indicated that, after controlling for pretreatment symptom severity, there was a large effect size for higher resting RSA predicting less severe caregiver‐reported posttreatment PTSD symptoms, β = −.52, p =.058, and higher RSA during recovery predicting less severe child‐reported posttreatment PTSD symptoms, β = −.70, p =.056, although these findings were not significant. These preliminary results offer important insights for future studies to investigate how the ability to regulate RSA informs which children need additional support to benefit from psychotherapeutic treatment. [ABSTRACT FROM AUTHOR]

Regulatory efforts are hypothesized to affect associations between emotions and physiology (i.e., concordance) to facilitate adaptive functioning. Assessing the role of coping on physiological–emotional concordance during ecologically relevant scenarios can elucidate whether concordance can serve as a biomarker of risk or resilience. The present study assessed self‐reported coping as a moderator of minute‐to‐minute associations between autonomic nervous system activity and emotions (i.e., physiological–emotional concordance) in caregivers (N = 97) and adolescents (N = 97; ages 10–15) during a dyadic conflict task. Models included physiological variables (sympathetic, skin conductance level [SCL]; and parasympathetic, respiratory sinus arrhythmia [RSA]) and their interaction (SCL × RSA) as predictors of emotions, with coping variables as moderators. Caregivers' use of primary control coping (e.g., problem solving and emotional expression) and secondary control coping (e.g., cognitive reappraisal and acceptance) use in response to family stress predicted more positive emotional experiences during the laboratory conflict task. Adolescents' use of secondary control coping moderated the SCL–emotion association, such that increases in momentary SCL were associated with more positive emotion ratings for youth reporting higher secondary control coping. For youth who report more adaptive trait‐level coping skills, momentary changes in SCL may reflect active engagement and attentiveness to facilitate more positive emotional experiences. Findings advance our understanding of the interrelationships between physiological responses and psychological experiences during relevant, interactive scenarios. Autonomic responses are differentially related to affective states depending on the coping strategies that adolescents employ, suggesting that concordance may be associated with intervention targets (i.e., coping skills). Regulatory efforts are hypothesized to affect physiological–emotional associations to facilitate adaptive functioning. Results suggest that autonomic responses differentially relate to emotions based on coping. For adolescents utilizing more secondary control coping skills, momentary skin conductance level changes may reflect active engagement and attentiveness to facilitate more positive emotional experiences. [ABSTRACT FROM AUTHOR]

Purpose: Tropical theileriosis is a tick-borne haemoprotozoan disease, and cardiac function assessment in buffaloes with theileriosis was poorly documented. Methods: The Present study was carried out from April 2022 to December 2022. Theileriosis was confirmed by microscopic examination of stained blood smears and lymphnode smears further confirmed by PCR assay. Electrocardiography was performed by using the base apex lead system, and echocardiography was performed by using the right parasternal view. Results: The incidence of theileriosis was 16.25% by examination of stained blood smears, and 30.42% by PCR examination in 240 buffaloes. Repeatedly noted clinical signs were the absence of rumination, anorexia, loss of milk yield, depressed demeanour, emaciation, hyperthermia, lymphadenopathy, tick infestation, tachycardia, cardiac arrhythmia, and increased intensity of heartbeat. Haematological findings disclosed decreased haemoglobin, packed cell volume, total erythrocyte count, and neutrophils; increased eosinophils and monocytes. Serum biochemical findings revealed decreased albumin, albumin/globulin ratio, glucose, calcium, phosphorous, sodium, potassium, and chloride; increased globulin, aspartate aminotransferase, bilirubin, blood urea nitrogen, creatinine, cholesterol, lactate dehydrogenase, gamma-glutamyl transferase, and creatine kinase myocardial band isoenzymes. Electrocardiography explorations were sinus tachycardia, broad T wave, and sinus arrhythmia. Echocardiography examination showed ventricular wall thickening, cardiac chamber dilatation, valvular defects/valvular regurgitation, and pericarditis/cardiac tamponade. Conclusion: The present research proposes the changes in the electrocardiography and echocardiography findings in buffaloes with theileriosis, which are essential in clinics to identify the secondary complications during theileriosis and formulate therapeutics. [ABSTRACT FROM AUTHOR]

Background: Heart rate variability (HRV) analysis has shown promise as a valuable complementary tool for clinical assessment in trauma cases. This study aims to evaluate the utility of HRV in monitoring different severities of hemorrhagic shock (HS) and its correlation with traditional hemodynamic and metabolic parameters. Methods: Male Sprague–Dawley rats were divided into different experimental groups, including those with and without vagotomy, and were exposed to different classes of decompensatory HS. To induce varying severities of HS, volume resuscitation was delayed by gradually returning 0%, 20%, or 50% of the shed blood volume at the end of the compensation phase, referred to as 0% DFR, 20% DFR, and 50% DFR class, respectively. Hemodynamic parameters were monitored, and HRV was calculated. Levels of TNF-α and IL-10 were determined in lung tissue at the end of the experiments. Correlations between HRV, hemodynamic parameters, inflammatory gene expression and arterial blood gas variables were evaluated. Results: HRV showed increased power of the low-frequency (LF) and respiratory sinus arrhythmia (RSA) in all groups during the hypotension phase of HS (Nadir 1). Subdiaphragmatic vagotomy blunted the increase in the LF component in the Nadir 1. After volume resuscitation, systolic blood pressure (SBP), RSA and LF returned to baseline in the 0% DFR and 20% DFR classes. However, animals in 50% DFR class exhibited a reduced SBP and LF and lower pH. Notably, strong correlations were found between LF and SBP as well as tissue hypoperfusion markers. The expression of TNF-α in the lung was increased in all HS groups, while this gene expression was significantly higher in the vagotomized animals. Conclusion: The alterations in HRV components were found to be significantly correlated with the hemodynamic and metabolic status of the animals, while showing no association with inflammatory responses. Additionally, the intervention of subdiaphragmatic vagotomy significantly impacted both HRV components and inflammatory responses. Collectively, these findings suggest the potential of HRV components for the assessment of the presence and severity of HS. [ABSTRACT FROM AUTHOR]

This study examined whether parental sensitivity during distressing and non‐distressing mother–infant interactions predicts changes in young children's respiratory sinus arrhythmia (RSA) activity. Baseline RSA levels were collected from 83 children (49% female, 51% male) when children were 7 and 18 months old. Children's RSA reactivity and RSA recovery during the still‐face paradigm were collected when children were 7 months and during the strange situation procedure at 18 months. Controlling for stability of RSA activity over time, maternal sensitivity during distressing interactions at 7 months predicted changes in children's baseline RSA levels (β = −0.30) and children's RSA recovery (β = 0.25). Young children who experienced higher levels of sensitivity at 7 months had lower resting RSA levels and exhibited greater RSA recovery at 18 months. These results suggest that changes in young children's RSA activity are meaningfully related to their early caregiving experiences. Highlights: We examined whether maternal sensitivity during infancy predicts changes in children's RSA activity from infancy to toddlerhood.Children who experienced higher levels of maternal sensitivity during infancy showed greater RSA recovery from a stressor during toddlerhood.Children who experienced higher levels of maternal sensitivity during infancy had lower resting RSA levels during toddlerhood. [ABSTRACT FROM AUTHOR]

We examined if there were profiles of infants' behavioural and physiological responses during the still‐face and if these profiles were predicted by maternal sensitivity. Participants included 230 mothers (40.4% non‐white) and their 2‐month‐old infants (48.7% female). Three profiles were identified: continually increasing negative affect and decreasing respiratory sinus arrhythmia (RSA) (17.39%); modest, classic still‐face effect for negative affect and RSA (64.35%); high negative affect, late decreasing RSA (18.26%). Infants of highly sensitive mothers were more likely to be in the modest, classic still‐face effect for negative affect and RSA profile than in the continually increasing negative affect and decreasing RSA and the high negative affect, late decreasing RSA profiles. Additionally, infants of mothers who were high in maternal sensitivity were more likely to be in the continually increasing negative affect and decreasing RSA profile compared to the high negative affect, late decreasing RSA profile. The findings demonstrate heterogeneity in infant responses and that maternal sensitivity is an important predictor of children's behavioural and physiological responses to stressors. [ABSTRACT FROM AUTHOR]

Temperamental inhibitory control is a foundational capacity for children's social, emotional, and behavioral development. Even though temperament is suggested to have a biological basis, the physiological indicators of inhibitory control remain unclear amid mixed empirical results. In this study, we leveraged a multicohort longitudinal design to examine resting respiratory sinus arrhythmia (RSA) as a physiological correlate of inhibitory control across the early and middle childhood years. Data were collected annually across four time points from cohorts of 4- (n = 150, Mage = 4.53; SD = 0.30; 49.7% female) and 8- (n = 150; Mage = 8.53; SD = 0.29; 49.7% female) year-old children and their caregivers. There were weak, albeit significant, associations between resting RSA and caregiver-reported inhibitory control in middle childhood but not in early childhood. A stronger association was found for older children when latent trait assessments of RSA and inhibitory control were derived from commonalities across the four annual assessments. We conclude that using repeated measures to extract latent trait scores increases power to detect potential physiological indicators of temperament. Public Significance Statement: In the current study we examined resting respiratory sinus arrhythmia (RSA) as a biological correlate of temperamental inhibitory control with a multicohort, 4-year longitudinal design across early and middle childhood. The analyses examining associations between resting RSA and inhibitory control across the latent trait models (derived from four repeated measures) showed significant associations between resting RSA and inhibitory control in middle childhood but not in early childhood. Results indicated that the biological correlates of temperamental inhibitory control might become more crystalized in middle childhood and showed that the use of repeated measures to extract latent trait scores would increases power to detect potential physiological indicators of temperamental inhibitory control. [ABSTRACT FROM AUTHOR]

Shyness is a temperamental trait that refers to fear and wariness in the face of social novelty and is known to have a biological basis. One proposed physiological correlate of shyness has been the change in respiratory sinus arrhythmia (RSA) from baseline to a stressor. However, past research linking shyness and RSA change has been mixed, which may be, in part, due to a failure to carefully consider the context under which RSA change is measured and the directionality of relations. Using a longitudinal design and cross-lagged analysis (N= 103, 52 girls), we examined parent-reported shyness and RSA change during a stranger approach task (social stressor) and a locked box task (nonsocial stressor) at ages 3 (Mage at Time 1 = 3.50 years, SDage = 0.19 years) and 4 (Mage at Time 2 = 4.76 years, SDage = 0.38). Cardiac vagal withdrawal during the stranger approach task, but not during the frustration task, at age 3 positively predicted shyness at age 4. Shyness at age 3 did not predict cardiac vagal change in either context at age 4. We also found that changes in RSA measured during the frustration task were stable across time, but changes in RSA measured during the stranger approach task were not stable across time, suggesting a developmental change in physiological regulatory systems to social threat. These results suggest that, although biology may come first in shaping children's behavior, this relation depends critically on the context and the incentives in the child's environment. Public Significance Statement: At age 3, cardiac vagal withdrawal, a physiological index of reactivity, was positively related to shyness 1 year later. This relation was specific to cardiac vagal withdrawal measured in a social threat context but not in a frustrating context that was less socially threatening. These results highlight the importance of considering context when examining biological factors that place individuals at greater risk of developing shyness. [ABSTRACT FROM AUTHOR]

Physiological synchrony is an important biological process during which parent–child interaction plays a significant role in shaping child socioemotional adjustment. The present study held a context‐dependent perspective to examine the conditional association between parent–child physiological synchrony and child socioemotional adjustment (i.e., relationship quality with parents and child emotion regulation) under different (i.e., from highly unsupportive to highly supportive) emotional contexts. One hundred and fifty school‐age Chinese children (Mage = 8.64 years, 63 girls) and their primary caregivers participated in this study. After attaching electrocardiogram (ECG) electrodes, parent–child dyads were instructed to complete a 4‐minute conflict discussion task. Parent–child physiological synchrony was calculated based on the within‐dyad association between parents' and children's respiratory sinus arrhythmia (RSA) levels across eight 30‐second epochs. Parental emotional support, child relationship quality with parents, and child emotion regulation during the discussion task were coded by trained research assistants. Supporting our hypotheses, parental emotional support moderated the relations of parent–child RSA synchrony with both child relationship quality with parents and child emotion regulation. Furthermore, the Johnson‐Neyman technique of moderation indicated that the associations between parent and child RSA synchrony and child socioemotional adjustment indicators shifted from negative to positive as the parental emotional support became increasingly high. Our findings suggest that parent–child physiological synchrony may not be inherently adaptive or maladaptive, highlighting the importance of understanding the function of parent–child physiological synchrony under specific contexts. Research Highlights: Physiological synchrony may not be inherently adaptive or maladaptive, and the meanings of parent–child physiological synchrony might be contingent on contextual factors.Parental emotional support moderated the relations between parent–child respiratory sinus arrhythmia (RSA) synchrony and child socioemotional adjustment indicators (i.e., child relationship quality with parents and child emotion regulation).More positive/less negative parent–child RSA synchrony was associated with better child socioemotional adjustment under a supportive emotional context, whereas with poorer child socioemotional adjustment under an unsupportive emotional context.These findings highlight the significance of considering the emotional context in physiological synchrony studies. [ABSTRACT FROM AUTHOR]

Background: Wearable technology is increasingly used in clinical practice and research to monitor functional gastrointestinal symptoms and mental health. Aims: This article explores the potential of wearable sensors to enhance the understanding of the autonomic nervous system (ANS), particularly its role in linking psychological and gastrointestinal function. The ANS, facilitates brain‐gut communication and is responsive to psychosocial conditions. It is implicated in disorders related to psychological stress and gut‐brain interaction. Wearable technology enables tracking of the ANS in daily life, offering complementary and alternative methods from traditional lab‐based measures. This review places focus on autonomic metrics such as respiratory sinus arrhythmia, vagal efficiency, and electrodermal activity as well as self‐reports of autonomic symptoms. Discussion: Potential applications include use of wearable sensors for tracking autonomic activity in disorder of gut‐brain interaction such as cyclic vomiting syndrome, in which ANS dysregulation may be triggered by psychosocial factors. Considerations for data interpretation and contextualization are addressed, acknowledging challenges such as situational confounders of ANS activity and accuracy of wearable devices. [ABSTRACT FROM AUTHOR]

Family environment, emotion regulation and biological sensitivity have been shown to be associated with adolescents' externalizing problem behaviours. However, findings regarding respiratory sinus arrhythmia (RSA) reactivity are mixed and sometimes contradictory. This study aims to clarify the roles of RSA reactivity and anger regulation in the relationship between negative family expressiveness (NFE) and adolescents' externalizing behaviour by measuring RSA reactivity during the Parent–Adolescent Interaction Task (PAIT), designed to simulate a naturalistic negative family environment. In this study, 125 Chinese adolescents (M = 13.95 years, SD = 0.95; 48% male) completed questionnaires assessing negative family expressiveness, anger regulation and externalizing problems. Additionally, we collected electrocardiogram and respiration data during both the resting period and a 10‐min PAIT. Results showed that anger regulation mediated the relationship between NFE and externalizing problem behaviours. Moreover, adolescents' RSA reactivity moderated this mediation effect, even after controlling for baseline RSA. Greater RSA suppression potentially indicated greater susceptibility, with the relationship between NFE and anger regulation being more pronounced in adolescents with greater RSA suppression compared to those with lesser RSA suppression. These findings highlight the importance of considering physiological systems, especially within the context of adverse family environments, when studying the relationships with externalizing problems. [ABSTRACT FROM AUTHOR]

Respiratory sinus arrhythmia (RSA), an index of the parasympathetic nervous system activity, has been considered indicative of stress response and emotion regulation. However, the relationship between RSA and anxiety remains inconclusive, partly because previous research has primarily focused on static RSA levels. In this nonclinical sample (N = 75, Mage = 20.89 ± 1.72 SD, 48 males), we used a damped oscillator model to characterize RSA dynamics across 30‐s epochs while participants completed the Trier social stress test. Results showed that RSA constantly oscillated during the three periods of TSST (namely Rest, Stress, and Recovery). Importantly, slower RSA oscillation in the Stress period was related to elevated state anxiety, whereas in the Recovery period, it was related to higher trait anxiety. These findings demonstrated the dynamic nature of RSA during the whole course of stress response. Slower RSA oscillation may indicate inflexible and tardy physiological regulation which may give rise to anxiety issues. Compared to static perspectives on aberrant autonomic arousal and psychopathology, our findings revealed the homeostatic dynamics underlying physiological regulation during stress responses. We found respiratory sinus arrhythmia (RSA) spontaneously oscillated over time to rapidly modulate internal resources in response to contextual demands. Consequently, slower RSA oscillation, indicative of vagal inflexibility, suggested risks of stress dysregulation such as anxiety. [ABSTRACT FROM AUTHOR]

Black adults' prior exposure to racial discrimination may be associated with their acute parasympathetic reactivity to and recovery from a new race‐related stressor. Existing analytical approaches to investigating this link obscure nuances in the timing, magnitude, and patterns of these acute parasympathetic nervous system (PNS) responses. In a re‐analysis of a prior study, we utilize an hidden Markov model (HMM) approach to examine how prior experiences of racial discrimination are associated with intraindividual patterns of (1) physiological states of PNS activity and (2) patterns of and variability in transitions between these physiological states. Participants (N = 118) were Black young adults (range 18–29 years; Mage = 19.67, SDage = 2.04) who completed an online survey to index prior racial discrimination exposure, followed by an in‐person lab visit during which their PNS activity in response to a race‐related stress task was measured via electrocardiogram and converted into respiratory sinus arrhythmia. HMMs indicated evidence for two states: baseline and a second state representing a significant reduction in respiratory sinus arrhythmia. Most participants (93.22%) demonstrated a blunted response to the task, indicating that they did not transition from baseline during the procedure. Prior racial discrimination was not associated with HMM states or state transition parameters. Blunted physiological responses may be an important area of future investigation that could inform early life course mental and physical health screenings. [ABSTRACT FROM AUTHOR]

Maternal depressive symptoms are a crucial risk factor for children's internalizing problems, though positive mother–child relationships may buffer this risk transmission. Mother–child physiological coregulation (e.g. synchrony) has emerged as a potentially important mechanism of developmental psychopathology and may play a role in the transmission of internalizing symptoms. In this two-wave longitudinal study, we examined whether and how mother–infant physiological synchrony (of respiratory sinus arrhythmia; RSA) moderated the association between maternal postnatal depressive symptoms and children's internalizing problems in a rural, low-SES community sample (N = 166 dyads). At 6 months, mother–infant RSA synchrony and infant negative affect were assessed during free play. Mother reported their depressive symptoms at 6 months and children's internalizing problems at 24 months. Multilevel structural equation models indicated that mother–infant dyads demonstrated significant and positive RSA synchrony on average and RSA synchrony significantly moderated the association between maternal depressive symptoms and children's internalizing problems even after controlling for infant negative affect. Greater maternal depressive symptoms were associated with higher child internalizing problems when RSA synchrony was lower but not when it was higher. This finding suggests that mother–infant RSA synchrony may operate as a resilience factor for the intergenerational transmission of internalizing symptoms in community samples. [ABSTRACT FROM AUTHOR]

This study examined how temporal associations between parents' physiological and behavioral responses may reflect underlying regulatory difficulties in at-risk parenting. Time-series data of cardiac indices (second-by-second estimates of inter-beat intervals – IBI, and respiratory sinus arrhythmia – RSA) and parenting behaviors were obtained from 204 child welfare-involved parents (88% mothers, M age = 32.32 years) during child-led play with their 3- to 7-year-old children (45.1% female; M age = 4.76 years). Known risk factors for maltreatment, including parents' negative social cognitions, mental health symptoms, and inhibitory control problems, were examined as moderators of intra-individual physiology-behavior associations. Results of ordinary differential equations suggested increases in parents' cardiac arousal at moments when they showed positive parenting behaviors. In turn, higher arousal was associated with momentary decreases in both positive and negative parenting behaviors. Individual differences in these dynamic processes were identified in association with parental risk factors. In contrast, no sample-wide RSA-behavior associations were evident, but a pattern of increased positive parenting at moments of parasympathetic withdrawal emerged among parents showing more total positive parenting behaviors. This study illustrated an innovative and ecologically-valid approach to examining regulatory patterns that may shape parenting in real-time and identified mechanisms that should be addressed in interventions. [ABSTRACT FROM AUTHOR]

Dexmedetomidine is an a2-adrenergic agonist that promotes deep sedation and analgesia. Ketamine is a dissociative anesthetic that exerts a negative inotropic effect, resulting in increased heart rate. Methadone, a full opioid agonist, causes mild respiratory depression and bradycardia. This study aimed to demonstrate the cardiovascular effects of the combination of dexmedetomidine, ketamine, and methadone in sedating a healthy dog undergoing echocardiographic and electrocardiographic examinations. The patient was sedated, and one hour after the sedative effects had subsided, the mentioned examinations were performed. Six months later, the examinations were repeated without the use of sedatives. The dog received 2 µg/kg of dexmedetomidine, 1 mg/kg of ketamine, and 0.3 mg/kg of methadone intramuscularly. The electrocardiogram showed sinus bradycardia, first-degree atrioventricular block, second-degree atrioventricular block Mobitz type II, and an increase in QRS duration, suggesting left ventricular overload. When performed without sedation, only sinus arrhythmia was observed. The echocardiogram showed normal parameters for the species in both evaluation periods. It can be concluded that the cardiovascular effects observed are attributable to dexmedetomidine, given that the dose of ketamine used was analgesic, and the sedative effect of dexmedetomidine was enhanced by methadone. [ABSTRACT FROM AUTHOR]

Objectives: The present study examined whether immigration stress was related to decreased capacities for psychophysiological stress regulation (as indexed by respiratory sinus arrhythmia [RSA]) and whether lower RSA, in turn, was related to decreased maternal sensitivity. The buffering effect of familism values was also evaluated, such that familism values were expected to minimize associations between immigration stress, RSA, and sensitivity. Method: Data were drawn from a longitudinal study of Mexican immigrant mothers (N = 277; Mage = 28 years). Mothers self-reported immigration stress and familism values, and mothers' resting RSA and sensitivity were assessed during laboratory visits. Results: Higher immigration stress was associated with higher RSA (B =.15, SE =.07, p =.04) but was unrelated to maternal sensitivity. Moreover, links between more immigration stress and higher RSA were more pronounced among mothers who reported stronger familism values (B =.20, SE =.07, p =.003). Conclusions: The present study contributes to our understanding of the sequelae of immigration stress in Mexican immigrant mothers and the cultural resiliency factors that may alter its effects. In contrast to hypotheses, findings suggested that mothers who endorse more immigration stress may also exhibit higher RSA, and links may be more pronounced among those with strong familism values. Further research is needed to advance understanding of resiliency processes that promote family functioning in vulnerable populations. Public Significance Statement: Immigration stress can present challenges for parental and family functioning, but pathways are not fully understood. Study findings suggest that Mexican immigrant mothers may demonstrate physiological resiliency in the face of immigration stress and that familism values may be a key cultural consideration in the promotion of well-being in Mexican immigrant families. [ABSTRACT FROM AUTHOR]

Human interpersonal capacities emerge from coordinated neural, biological, and behavioral activity unfolding within and between people. However, developmental research to date has allocated comparatively little focus to the dynamic processes of how social interactions emerge across these levels of analysis. Second-person neuroscience and dynamic systems approach together to offer an integrative framework for addressing these questions. This study quantified respiratory sinus arrhythmia and social behavior (∼360 observations per system) from 44 mothers and typically developing 9-month-old infants during a novel modified "still-face" (text message perturbation) task. Stochastic autoregression models indicate that the infant parasympathetic nervous system is coupled within and between people second by second and is sensitive to social context. Intraindividual, we found positive coupling between infants' parasympathetic nervous system activity and their social behavior in the subsequent second, but only during the moments and periods of active caregiver engagement. Between people, we found a bidirectional coregulatory feedback loop: Mothers' parasympathetic activity positively predicted that of their infant in the subsequent second, a form of synchrony that decreased during the text message perturbation and did not fully recover. Conversely, infant parasympathetic activity negatively predicted that of their mother at the subsequent second, a form of synchrony that was invariant over social context. Findings reveal unidirectional parasympathetic coupling within infants and a complementary allostatic feedback loop between mother and infant parasympathetic systems. They offer novel evidence of a dynamic, socially embedded parasympathetic system at previously undocumented timescales, contributing to both basic science and potential clinical targets to better support adaptive, multisystem social development. Public Significance Statement: This study investigated how the subconscious, "rest and digest" parasympathetic nervous system supports babies' abilities to interact with others. Results suggest that the parasympathetic system changes in real-time to help babies regulate their bodies to engage socially and that parasympathetic activity is synchronized between mothers and babies in a coregulatory fashion. Findings improve scientific knowledge and may, in the future, aid clinical efforts to support children's development. [ABSTRACT FROM AUTHOR]

This study sought to advance our understanding of how observed child self-regulation, parenting, and their interaction were associated with children's dynamic physiological stress reactivity indexed by respiratory sinus arrhythmia (RSA) reactivity trajectories. Participants were 85 three-year-old children (54% female) and their mothers oversampled for lower income, higher stressful life events, and higher child maltreatment risk. Child behavioral regulation, assessed as compliance and noncompliance, and maternal supportive parenting were observed during a challenging dyadic puzzle task. Results showed that child RSA exhibited quadratic change across the task on average, characterized by an expected initial decrease and subsequent recovery. Child behavioral regulation and its interaction with maternal supportive parenting were associated with interindividual differences in child RSA reactivity trajectories after controlling for child resting RSA. Children with higher compliance or lower noncompliance showed RSA decreases in response to task stressors but exhibited subsequent RSA recovery only when mothers displayed higher supportive parenting. Children with lower compliance or higher noncompliance displayed negligible RSA changes overall across the task, suggesting blunted or compromised RSA reactivity, regardless of supportive parenting levels. These findings demonstrate novel evidence that preschoolers' better behavioral regulation is related to their more adaptive physiological reactivity to stressors and that supportive parenting is needed to facilitate physiological recovery even in relatively better-regulated preschoolers. Public Significance Statement: This study demonstrates that during challenging mother–preschooler interactions, preschoolers who exhibit better behavioral regulation with mothers and experience higher levels of supportive parenting show the most adaptive physiological reactivity to stressors and efficient physiological recovery after stressors have passed. Child self-regulation and parenting in challenging interactions are potential intervention targets to promote adaptive physiology and behaviors. [ABSTRACT FROM AUTHOR]

Key points Microneurographic recordings of the human cervical vagus nerve have revealed the presence of multi‐unit neural activity with measurable cardiac rhythmicity. This suggests that the physiology of vagal neurones with cardiovascular regulatory function can be studied using this method. Here, the activity of cardiac rhythmic single units was discriminated from human cervical vagus nerve recordings using template‐based waveform matching. The activity of 44 cardiac rhythmic neurones (22 with myelinated axons and 22 with unmyelinated axons) was isolated. By consideration of each unit's firing pattern with respect to the cardiac and respiratory cycles, the functional identification of each unit was attempted. Of note is the observation of seven cardiac rhythmic neurones with myelinated axons whose activity was recruited or enhanced by slow, deep breathing, was maximal during the nadir of respiratory sinus arrhythmia, and showed an expiratory peak. This is characteristic of cardioinhibitory efferent neurones, which are responsible for respiratory sinus arrhythmia. The remaining 15 cardiac rhythmic neurones with myelinated axons were categorised as cardiopulmonary receptors or arterial baroreceptors based on the position of their peak in firing with respect to the R‐wave of the cardiac cycle. This latter method is not viable for neurones with unmyelinated axons due to their slow and unknown conduction velocities. With the exception of three neurones whose expiratory modulation implicates them as cardiac‐projecting efferent neurones, this population is likely dominated by arterial baroreceptors. In conclusion, the activity of single units with cardiovascular function has been discriminated within the human cervical vagus, enabling their systematic study. Recordings of the electrical activity of the vagus nerve have recently been made at the level of the neck in humans. Examination of the gross activity of this nerve reveals subpopulations of neurones whose activity fluctuates in time with the heart's beat, suggesting that the neurones that monitor or modify cardiac function can be studied using this method. Here, the activity of individual cardiac rhythmic neurones was isolated from human vagus nerve recordings using template‐based spike sorting. The relationship between this activity and the cardiac and respiratory cycles was used as a means of classifying each neurone. Neuronal firing patterns that are consistent with that of neurones that modify cardiac function, including heart‐slowing ‘cardioinhibitory’ neurones, as well as neurones that inform the brain of cardiovascular status were observed. This approach enables, for the first time, the systematic study of the function of these neurones in humans in both health and disease. [ABSTRACT FROM AUTHOR]

Emotion involves oneself in relation to a subject of attention; e.g., sadness is to be sad about something/someone. This study examined emotional responses to perceiving a loss of connection from oneself. Evidence suggests that Europeans tend to perceive salient objects in the foreground, while East Asians are more likely to perceive holistically, considering the interrelationships between the context and the object. We studied how this distinction affected European Americans' (EA) and Chinese Americans' (CA) sensitivity to perceiving the loss of connection. Both groups were exposed to loss by playing Cyberball, a balltossing video game, and then watched a film clip on grief. We hypothesized that EA would respond with increasing heart rate (HR) variance around the mean when perceiving loss. CA were predicted to show no difference from controls. We also hypothesized that EA would feel sadder, in terms of decreased HR and increased respiratory sinus arrhythmia (RSA), earlier during the film clip. In total, 53 subjects were recruited, of which 40 were EA (47.5% women, age 21.08 ± 1.94 years) and 13 were CA (61.5% women, age 21.05 ± 1.74 years); 25 subjects (19 EA, 6 CA) received 2 out of 48 balls tossed in Cyberball and the controls received 10. ECG, respiration, and facial electromyography (fEMG) data were acquired. The results during Cyberball showed that EA's HR variance relative to baseline (HR SDc/b) had an upward trend on perceiving loss. Contrary to prediction, CA also showed higher levels of HR variance relative to baseline. The ANOVA of HR SDc/b revealed that the interaction effect of two factors, time and condition, was statistically significant (p = 0.009). However, as predicted, EA in the experimental condition had decreased HR and increased RSA, a sign of withdrawal in sadness, 30 to 60 s into the sad clip. fEMG data at the corrugator muscle revealed that EA activated higher peak intensity 5.5 s earlier than CA (increased 1.571 vs. 0.844). This difference, however, was not statistically significant. The evidence suggests that increased exposure to loss automatically led to increased HR variance in both groups even when subjects were informed that players were computer-generated. However, the effect was stronger on EA to increase their arousal and sensitivity to grief thereafter. [ABSTRACT FROM AUTHOR]

Cardiac memory refers to T-wave inversions (TWI) on electrocardiograms (ECGs) after an episode of abnormal ventricular activation or wide electrical activity of ventricular muscles (QRS complex). We present the case of a 62-year-old woman with symptomatic bradycardia due to sinus pause. She immediately underwent temporary transvenous ventricular pacing. In the following days, intrinsic normal sinus rhythm was resumed at 69 bpm and a narrow QRS was observed (97 ms). Additionally, deep TWI was observed in leads II, III, aVF, and V3-V6. The distribution of TWI, normal echocardiogram and laboratory results, non-significant coronary angiogram, and recent right ventricular pacing correspond to possible cardiac T-wave memory. Follow-up 12-lead ECG four weeks later showed that T-wave morphology returned to normal baseline. This further confirmed the final diagnosis of cardiac memory-induced TWI. Recognizing cardiac memory-induced TWI is important for physicians to facilitate proper evaluation and management of TWI and prevent unnecessary further cardiac diagnostic tests. [ABSTRACT FROM AUTHOR]

Slow-paced breathing at an individual's resonance frequency (RF) is a common element of heart rate variability (HRV) biofeedback training (Laborde et al. in Psychophysiology 59:e13952, 2022). Although there is strong empirical support for teaching clients to slow their respiration rate (RR) to the adult RF range between 4.5 and 6.5 bpm (Lehrer & Gevirtz, 2014), there have been no definitive findings regarding the best inhalation-to-exhalation (IE) ratio to increase HRV when breathing within this range. Three methodological challenges have frustrated previous studies: ensuring participants breathed at the target RR, IE ratio, and the same RR during each IE ratio. The reviewed studies disagreed regarding the effect of IE ratios. Three studies found no IE ratio effect (Cappo & Holmes in J Psychosom Res 28:265-273, 1984; Edmonds et al. in Biofeedback 37:141-146, 2009; Klintworth et al. in Physiol Meas 33:1717-1731, 2012). One reported an advantage for equal inhalations and exhalations (Lin et al. in Int J Psychophysiol 91:206?211, 2014). Four studies observed an advantage for longer exhalations than inhalations (Bae et al. in Psychophysiology 58:e13905, 2021; Laborde et al. in Sustainability 13:7775, 2021; Strauss-Blasche et al. in Clin Exp Pharmacol Physiol 27:601?60, 2000; Van Diest et al. in Appl Psychophysiol Biofeedback 39:171?180, 2014). One study reported an advantage for longer inhalations than exhalations (Paprika et al. in Acta Physiol Hung 101:273?281, 2014). We conducted original (N = 26) and replication (N = 16) studies to determine whether a 1:2 IE ratio produces different HRV time-domain, frequency-domain, or nonlinear metrics than a 1:1 ratio when breathing at 6 bpm. Our original study found that IE ratio did not affect HRV time- and frequency-domain metrics. The replication study confirmed these results and found no effect on HRV nonlinear measurements. [ABSTRACT FROM AUTHOR]

This Committee Report provides methodological, interpretive, and reporting guidance for researchers who use measures of heart rate (HR) and heart rate variability (HRV) in psychophysiological research. We provide brief summaries of best practices in measuring HR and HRV via electrocardiographic and photoplethysmographic signals in laboratory, field (ambulatory), and brain‐imaging contexts to address research questions incorporating measures of HR and HRV. The Report emphasizes evidence for the strengths and weaknesses of different recording and derivation methods for measures of HR and HRV. Along with this guidance, the Report reviews what is known about the origin of the heartbeat and its neural control, including factors that produce and influence HRV metrics. The Report concludes with checklists to guide authors in study design and analysis considerations, as well as guidance on the reporting of key methodological details and characteristics of the samples under study. It is expected that rigorous and transparent recording and reporting of HR and HRV measures will strengthen inferences across the many applications of these metrics in psychophysiology. The prior Committee Reports on HR and HRV are several decades old. Since their appearance, technologies for human cardiac and vascular monitoring in laboratory and daily life (i.e., ambulatory) contexts have greatly expanded. This Committee Report was prepared for the Society for Psychophysiological Research to provide updated methodological and interpretive guidance, as well as to summarize best practices for reporting HR and HRV studies in humans. [ABSTRACT FROM AUTHOR]

Emotion dysregulation is implicated in child social anxiety and its etiology. Child emotion dysregulation has been studied via physiological indicators (e.g., respiratory sinus arrhythmia [RSA]) and behavioral indicators (e.g., effortful control). Previous work suggests that physiological indicators of regulation may predict outcomes in a non-linear manner and must be considered within the context of other intrapersonal factors, perhaps including effortful control. To this end, the current study tested effortful control as a moderator of the relation between RSA and child social anxiety, considering both linear and curvilinear patterns and controlling for inhibited temperament, an established predictor of child anxiety. Children (n = 119; 44% female) participated when they were 4 years old and entering school age (5 to 7 years). Mothers reported on children's effortful control (age 4) and social anxiety (school age). Children's RSA (age 4) was calculated from electrocardiogram data when they were at rest (i.e., baseline RSA) and when they were giving a speech. Results indicated that when children were high in effortful control, lower baseline RSA predicted higher social anxiety symptoms. Tentative evidence emerged for a relation between greater suppression of RSA during the speech compared to baseline and higher social anxiety symptoms when children were low in effortful control. Results support assessing the temperamental domain of effortful control as a contextualizing factor in the relation between psychophysiology and child anxiety outcomes. [ABSTRACT FROM AUTHOR]

The article presents a case study of a patient with ventricular tachycardia originating from the para-Hisian region, where detailed electrophysiological mapping and pacing maneuvers were used to identify the reentrant mechanism. It also discusses the effectiveness of entrainment pacing in determining the optimal ablation site, challenges associated with ablation in this anatomical region, and the role of detailed electroanatomical mapping in avoiding damage to the AV conduction system.

Background: Dexmedetomidine, an alpha 2 agonist, has emerged as a desirable sedative agent in the pediatric intensive care unit due to its minimal effect on respiratory status and reduction in delirium. Bradycardia and hypotension are common side effects, however there are emerging reports of more serious cardiovascular events, including sinus arrest and asystole. These case reports have been attributed to high vagal tone or underlying cardiac conduction dysfunction. Objectives: To describe the development of sinus arrest during sedation with dexmedetomidine in a patient without clinical features of high vagal tone, underlying cardiac conduction dysfunction, or intervening episodes of bradycardia. Case Presentation: An 11 month-old patient requiring sedation during mechanical ventilation for acute respiratory failure secondary to Adenovirus. To facilitate sedation, a dexmedetomidine infusion was initiated at.5 mcg/kg/hr and increased to maximum 1 mcg/kg/hr. Within 8 hours of initiating therapy, the patient had three episodes of sinus arrest. There was no intervening bradycardia between episodes and no further episodes occurred following discontinuation of dexmedetomidine. The patient did not have any clinical features associated with high vagal tone or underlying cardiac conduction dysfunction. Conclusions: As result of these findings, understanding risk factors for bradycardia, or more serious hemodynamic instability with dexmedetomidine infusions, is important to help identify high risk patients and weigh the associated risks and benefits of its administration. [ABSTRACT FROM AUTHOR]

Williams–Beuren syndrome (WBS) is a rare genetic condition caused by a chromosomal microdeletion at 7q11.23. It is a multisystem disorder characterized by distinct facies, intellectual disability, and supravalvar aortic stenosis (SVAS). Those with WBS are at increased risk of sudden death, but mechanisms underlying this remain poorly understood. We recently demonstrated autonomic abnormalities in those with WBS that are associated with increased susceptibility to arrhythmia and sudden cardiac death (SCD). A recently introduced method for heart rate variability (HRV) analysis called "heart rate fragmentation" (HRF) correlates with adverse cardiovascular events (CVEs) and death in studies where heart rate variability (HRV) failed to identify high-risk subjects. Some argue that HRF quantifies nonautonomic cardiovascular modulators. We, therefore, sought to apply HRF analysis to a WBS cohort to determine 1) if those with WBS show differences in HRF compared with healthy controls and 2) if HRF helps characterize HRV abnormalities in those with WBS. Similar to studies of those with coronary artery disease (CAD) and atherosclerosis, we found significantly higher HRF (4 out of 7 metrics) in those with WBS compared with healthy controls. Multivariable analyses showed a weak-to-moderate association between HRF and HRV, suggesting that HRF may reflect HRV characteristics not fully captured by traditional HRV metrics (autonomic markers). We also introduce a new metric inspired by HRF methodology, significant acute rate drop (SARD), which may detect vagal activity more directly. HRF and SARD may improve on traditional HRV measures to identify those at greatest risk for SCD both in those with WBS and in other populations. NEW & NOTEWORTHY: This work is the first to apply heart rate fragmentation analyses to individuals with Williams syndrome and posits that the heart rate fragmentation parameter W3 may enable detection and investigation of phenomena underlying the proarrhythmic short-long-short RR interval sequences paradigm known to precede ventricular fibrillation and ventricular tachycardia. It also forwards a novel method for quantifying sinus arrhythmia and sinus pauses that likely correlate with parasympathetic activity. [ABSTRACT FROM AUTHOR]

Children's risk of poorer mental health due to the COVID-19 pandemic may depend on risk and protective factors heading into the pandemic. This study examined same-day associations between COVID-19 stressors and children's mental health using a daily diary design across 14 days, and considered the moderating roles of pre-pandemic peer victimization experiences and resting respiratory sinus arrhythmia (RSA; an indicator of cardiac regulatory capacity). Forty-nine Canadian children aged 8–13 years (Mage = 10.69, 29 girls) participated in the final wave of a longitudinal study just prior to the pandemic and a daily diary extension during the pandemic (N = 686 pandemic measurement occasions). Multilevel modeling indicated that children had poorer mental health on days when they experienced a COVID-19 stressor (e.g., virtual academic difficulties, social isolation). A three-way interaction indicated that this association was stronger for those with higher pre-pandemic peer victimization experiences and lower pre-pandemic resting RSA; however, highly victimized children with higher resting RSA did not experience poorer mental health on days with COVID-19 stressors. Findings offer preliminary insights into the preceding risk and protective factors for children's mental health amidst major subsequent stress. [ABSTRACT FROM AUTHOR]

Background: Seabirds like penguins and petrels, living in Antarctic and sub-Antarctic regions, often feed hundreds or even thousands of kilometers away from the islands where they breed. They therefore adapted to endure prolonged fasting during egg incubation, enabling their partner to undertake foraging trips that can last up to two weeks. Aside from accumulating and consuming fat reserves, it is unclear whether seabirds have developed further adaptations to extended fasting periods. This lack of knowledge is in part due to their remote nesting location and their extreme sensitivity to manipulation. To overcome this lack of knowledge, we developed a non-invasive device to record the heart rate (HR) of burrow-nesting blue petrels (Halobaena caerulea) during egg incubation. For that, we encapsulated a small-size logger in a dummy egg to record electrocardiograms (ECGs) through the featherless incubation patch of the birds. Results: The blue petrels' HR (208 ± 15 beats per min [bpm]; n = 6) that we recorded during egg incubation was slower than the HR predicted by two different allometric functions regressing HR against body mass (242 and 250 bpm). Blue petrels' HR also presented cyclical variation correlated to respiration, resembling the physiological Respiratory Sinus Arrhythmia (RSA) described in humans and other species, and that is mainly modulated by the vagal nerve. Moreover, the basal HR of incubating blue petrels increased about every minute during egg movements that presumably reflect egg turning, important for embryo survival and development. During these events, blue petrels' HR increased up to a maximum of 296 ± 27 bpm for 18 ± 2 s (n = 6). We estimated that those egg movements increased energy expenditure (EE) by 8.4 ± 1.3%, which is approximately 10 times less than the energy increase induced by the disturbance linked with the removal of the dummy egg at the end of the experiment. Interestingly, we noticed that the beginning of HR increase preceded egg movements by 4.3 ± 0.9 s (n = 6), as if birds needed to gradually increase their metabolism to achieve the following action. As well, blue petrels needed 9.1 ± 1.3 s (n = 6) to recover basal levels of HR after the end of egg movements. Conclusion: We recorded for the first time ECGs, HR and RSA in blue petrels in a completely non-invasive way. This allowed us to observe (1) slow basal HR during egg incubation, which could save energy for prolonged fasting and (2) temporal HR increase, possibly necessary to reposition the egg for proper embryonic development. [ABSTRACT FROM AUTHOR]

ObjectiveMethodResultsConclusionThe literature on affective regulation in psychotherapy has traditionally relied on explicit client self-report measures. However, both clients’ and therapists’ affect fluctuate moment-to-moment during a session, highlighting the need for more implicit and continuous indices to better understand these dynamics. This study examined parasympathetic interpersonal and intrapersonal regulation dynamics between therapists and clients with Major Depressive Disorder during Supportive-Expressive Therapy.Data were collected from 52 dyads across five preselected sessions, using the Respiratory Sinus Arrhythmia (RSA) index. We employed a longitudinal Actor-Partner Interdependence Model, with clients self-reporting their functioning level before and after each session, as the moderator.Therapists’ RSA at one time point negatively associated with clients’ RSA at the next, and vice-versa, indicating interpersonal regulation. Clients’ RSA at one time point was positively associated with their RSA at the next, indicating intrapersonal regulation. However, only interpersonal regulation was significantly moderated by clients’ pre-to-post session functioning. Specifically, sessions where clients led positive dyadic RSA associations showed greater improvement in clients’ functioning than those led by therapists.Physiological interpersonal regulation, measured by RSA, may be a catalyst for change in depression treatment. Therapists who are responsive to clients’ arousal levels may help clients improve their functioning. [ABSTRACT FROM AUTHOR]

Background Post-traumatic stress symptoms (PTSS) were the most frequently reported mental health concern for youth during COVID-19, yet variations in youth's PTSS responses warrant empirical consideration. Features of the caregiving environment influence youth's responses to environmental stressors, and youth's parasympathetic nervous system regulation may qualify the magnitude and/or direction of these effects. This prospective investigation evaluated diathesis stress and differential susceptibility models of caregiving and parasympathetic influences on youth's PTSS responses to COVID-19. Method Participants were 225 caregiver-youth dyads (youth 49.8% female at birth; 88.4% non-white) followed from childhood through adolescence and COVID-19. Youth's resting respiratory sinus arrhythmia (RSA; M age = 6.11, s.d. = 0.21), caregiving features (i.e. attachment security [youth M age = 12.24, s.d. = 0.35] and caregiver internalizing psychopathology [caregiver M age = 39.29, s.d. = 6.78]) were assessed pre-pandemic. Youth's PTSS was assessed one year prior to the US COVID-19 pandemic (M age = 14.24, s.d. = 0.50) and during the spring of 2020 at the height of the pandemic (M age = 15.23, s.d. = 0.57). Results Youth's PTSS increased during COVID-19. Youth with relatively high resting RSA evidenced the lowest PTSS when their caregiving environment featured high attachment security or low caregiver internalizing problems, but the highest PTSS when their caregiving environment featured low attachment security or high caregiver internalizing problems. In contrast, PTSS levels of youth with relatively low or average resting RSA did not differ significantly depending on attachment security or caregiver internalizing. Conclusions Results are consistent with a differential susceptibility hypothesis, wherein relatively high resting RSA conferred heightened sensitivity to caregiving environments in a for-better-and-for-worse manner during COVID-19. [ABSTRACT FROM AUTHOR]

Many animal species do not breathe in a continuous, rhythmic fashion, but rather display a variety of breathing patterns characterized by prolonged periods between breaths (inter‐breath intervals), during which the heart continues to beat. Examples of intermittent breathing abound across the animal kingdom, from crustaceans to cetaceans. With respect to human physiology, intermittent breathing—also termed 'periodic' or 'episodic' breathing—is associated with a variety of pathologies. Cardiovascular phenomena associated with intermittent breathing in diving species have been termed 'diving bradycardia', 'submersion bradycardia', 'immersion bradycardia', 'ventilation tachycardia', 'respiratory sinus arrhythmia' and so forth. An examination across the literature of terminology applied to these physiological phenomena indicates, unfortunately, no attempt at standardization. This might be viewed as an esoteric semantic problem except for the fact that many of the terms variously used by different authors carry with them implicit or explicit suggestions of underlying physiological mechanisms and even human‐associated pathologies. In this article, we review several phenomena associated with diving and intermittent breathing, indicate the semantic issues arising from the use of each term, and make recommendations for best practice when applying specific terms to particular cardiorespiratory patterns. Ultimately, we emphasize that the biology—not the semantics—is what is important, but also stress that confusion surrounding underlying mechanisms can be avoided by more careful attention to terms describing physiological changes during intermittent breathing and diving. What is the topic of this review?This review examines the rather confusing semantics that has been used to describe patterns in the field of cardiorespiratory physiology as it applies to intermittent breathing, particularly in diving species.What advances does it highlight?This review highlights the various cardiorespiratory phenomena associated with intermittent breathing and diving. It highlights the semantic issues associated with describing each and offers a rationale for standardizing terms based on underlying mechanisms to reduce confusion and advance the study of cardiorespiratory phenomena in both medical and comparative physiological investigations. [ABSTRACT FROM AUTHOR]

Emotion regulation (ER) is a multifaceted construct, involving behavioral, cognitive, and physiological processes. Although autonomic coordination is theorized to play a crucial role in adaptive functioning, few studies have examined how different individual and contextual factors together may contribute to such coordination. This study examined the joint influences of narrative processing and emotional negativity/lability (N/L) traits on the coordination of the sympathetic and parasympathetic nervous systems in a sample of 112 children, ages 8–12 years (Mage = 10.15 years, SD = 1.33). Children completed a stress‐induction task followed by an interview about the task. Children's trait‐level N/L was assessed via parent‐report on the Emotion Regulation Checklist. Narrative processing was assessed and coded based on children's narrative accounts of the event (i.e., causal coherence, overall emotional tone). Indexes of sympathetic (skin conductance response, SCR) and parasympathetic (respiratory sinus arrhythmia, RSA) functioning were derived from physiological data obtained during the interview. Results revealed that children's trait‐level N/L and narrative processing of the stressful event interacted to predict the RSA–SCR correlation. Specifically, children who were high on either N/L or narrative causal coherence, but not both, demonstrated significant RSA–SCR correlation. Similarly, children with high N/L and negative‐to‐neutral narratives, as well as those with low N/L and neutral‐to‐positive narratives, exhibited significant RSA–SCR correlation. This work provides empirical evidence that narrative processing and trait N/L, together with RSA–SCR correlation, work in tandem to regulate emotional arousal. This study examined the interactive roles of individual and contextual factors in association with autonomic coordination in ER. Children's trait‐level negativity/lability and narrative processing (i.e., causal coherence, the overall emotional tone) interacted to predict sympathetic and parasympathetic coordination. Findings empirically support that narrative processing and trait N/L, together with RSA–SCR correlation, work in tandem to regulate emotional arousals. [ABSTRACT FROM AUTHOR]

The importance of psychopathy for perpetration and maintenance of intimate partner violence (IPV) has been speculated. However, less is known about whether psychopathy would explain a psychophysiological response (cardiorespiratory and electrodermal) of IPV perpetrators dealing with acute stressors. Therefore, we first aimed to assess whether IPV perpetrators (n = 58) showed differences in psychopathic traits and their psychophysiological response to acute stress compared to nonviolent men (n = 53). Second, we examined in both groups whether psychopathic traits would explain a psychophysiological response when dealing with acute laboratory stress. Our results revealed that IPV perpetrators differed from controls in all the psychopathic traits, scoring higher on all psychopathy scales. Moreover, IPV perpetrators showed lower total respiratory sinus arrhythmia (RSA) levels than controls. Finally, regarding high total psychopathy scores, factor 1 and affective facet entailed low RSA levels in both groups and scoring high in lifestyle facet of factor 2 explained reduced heart rate (HR) changes in response to acute stress in both groups. All these results highlighted that a reduced vagal tone could be characteristic of psychopathic traits, especially for the affective facet of psychopathy. Therefore, it would be important to incorporate biological markers in combination with psychological measurements to clearly diagnose IPV perpetrators before starting intervention programs. This would increase our ability to improve IPV intervention therapeutic targets and reduce risk of recidivism. [ABSTRACT FROM AUTHOR]

Respiratory sinus arrhythmia (RSA) reflects the functioning of the nervous heart control, predominantly of a parasympathetic nature. The study of RSA mechanisms helps to reveal the physiological patterns of regulation of cardiac activity, and the development of new approaches to its assessment is an urgent medical task. This review will examine experimental approaches that have contributed to the development of modern ideas about the autonomic nervous system's role in the formation of RSA, as well as the connection between RSA and frequency-matched fluctuations in systemic blood pressure. In addition, we will consider new data on the phase relationships of fluctuations in heart rate and blood pressure in the frequency range of respiratory waves, obtained using wavelet analysis of these physiological signals. [ABSTRACT FROM AUTHOR]

Respiratory Sinus Arrhythmia (RSA) manifests as cyclic fluctuations in heart rate in synchrony with breathing. Gaining insights into the dynamics of RSA within the cardiac muscle functioning is crucial for comprehending its physiological and clinical significance. This study presents an analytical framework employing Markov chains to probe RSA patterns, with a specific emphasis on individuals with hypertension and arachnophobia. We delve into the concept of RSA and its potential cardiovascular implications, particularly among populations characterized by hypertension or normotension and fear of spiders. This study utilizes Markov chain modeling, an innovative method used to scrutinize RSA dynamics across diverse cohorts, with the aim of unveiling underlying patterns and mechanisms. This research contributes to the advancement of our understanding of RSA and its correlation with cardiac function across varied demographics, potentially guiding tailored diagnostic and therapeutic interventions. Our findings highlight significant disparities between hypertensive and normotensive participants, as well as spider-fearful individuals employing techniques to confront their fear compared with those without such strategies. [ABSTRACT FROM AUTHOR]

Slow paced breathing has been demonstrated to provide significant health benefits for a person's health, and, during breathing sessions, it is desirable to monitor that a person is actually compliant with the breath pacer. We explore the potential use of pulse rate variability to monitor compliance with a breath pacer during meditation sessions. The study involved 6 human subjects each participating in 2–3 trials, where they are asked to follow or not to follow the breath pacer, where we collected data on how the magnitude of pulse rate variability changed. Two methods, logistic regression and a running standard deviation technique, were developed to detect non-compliance with the breath pacer based on pulse rate variability metrics. Results indicate that using pulse rate variability alone may not reliably detect non-compliance with the breath pacer. Both models exhibited limitations in terms of false positives and false negatives, with accuracy ranging from 67 to 65%. Existing methods involving visual, audio, and motion signals currently perform better for monitoring compliance with the breath pacer. [ABSTRACT FROM AUTHOR]

This study examined the stability of Attachment Script Assessment (ASA) deactivation, hyperactivation, and anomalous content and their significance for parenting outcomes in mothers (Mage = 31 years; 78% White/European American) and 6-month-old infants. Comparable to ASA secure base script knowledge (SBSK), mothers' ASA deactivation, hyperactivation, and anomalous content were significantly, moderately stable over two years (r's =.40 -.43). Mothers' ASA hyperactivation and anomalous content were associated with greater maternal intrusiveness, whereas ASA deactivation was associated with greater detachment and less intrusiveness. Only ASA anomalous content was associated with lower maternal sensitivity. Mothers' ASA deactivation was associated with less dynamic change in respiratory sinus arrhythmia during the Still-Face Procedure—reflective of limited mobilization of physiological resources to support responding to infants. Findings support the validity of ASA deactivation, hyperactivation, and anomalous content scripts, and demonstrate their utility in examining adult attachment stability and predictive significance for parent-child outcomes. [ABSTRACT FROM AUTHOR]

The experience of empathy for pain is underpinned by sensorimotor and affective dimensions which, although interconnected, are at least in part behaviorally and neurally distinct. Spinal cord injuries (SCI) induce a massive, below‐lesion level, sensorimotor body–brain disconnection. This condition may make it possible to test whether sensorimotor deprivation alters specific dimensions of empathic reactivity to observed pain. To explore this issue, we asked SCI people with paraplegia and healthy controls to observe videos of painful or neutral stimuli administered to a hand (intact) or a foot (deafferented). The stimuli were displayed by means of a virtual reality set‐up and seen from a first person (1PP) or third person (3PP) visual perspective. A number of measures were recorded ranging from explicit behaviors like explicit verbal reports on the videos, to implicit measures of muscular activity (like EMG from the corrugator and zygomatic muscles that may represent a proxy of sensorimotor empathy) and of autonomic reactivity (like the electrodermal response and Respiratory Sinus Arrhythmia that may represent a general proxy of affective empathy). While no across group differences in explicit verbal reports about the pain stimuli were found, SCI people exhibited reduced facial muscle reactivity to the stimuli applied to the foot (but not the hand) seen from the 1PP. Tellingly, the corrugator activity correlated with SCI participants' neuropathic pain. There were no across group differences in autonomic reactivity suggesting that SCI lesions may affect sensorimotor dimensions connected to empathy for pain. To explore how sensorimotor deprivation affects empathic reactivity we recorded facial muscle (FM) and autonomic reactivity (AR) in controls and people with spinal cord injury (SCI) watching painful stimuli applied to a virtual, intact (hand) or deprived (foot) body part. SCI participants displayed reduced FM when viewing foot stimuli. AR was not differentially affected by group, stimulus or body part indicating that SCI affects sensorimotor rather than affective pain empathy. [ABSTRACT FROM AUTHOR]

This study investigated the role of autonomic nervous system (ANS) coordination in response to emotion in girls' and boys' development of relational (e.g., ignoring, excluding) and physical (e.g., hitting, kicking) aggression. Caregivers reported on children's relational and physical aggression at ages 6, 7, 8, and 10 years (N = 232, 50.4% girls, 46.6% Latinx). Sympathetic nervous system (assessed via pre-ejection period) and parasympathetic nervous system (assessed via respiratory sinus arrhythmia) reactivity were measured in response to video clips depicting fear, happiness, and sadness at age 7. Growth curve models indicated that ANS reactivity to sadness, but not to fear or happiness, was related to trajectories of relational aggression. In contrast, ANS reactivity to all three emotions was associated with trajectories of physical aggression. Effects differed across genders, indicating that distinct patterns of ANS reactivity to emotion may be involved in girls' and boys' development of aggression. Overall, these findings contribute to a growing literature documenting the role of ANS reactivity to emotion in aggressive behavior. Moreover, this study considers ANS reactivity to specific emotions, as related to both relational and physical aggression, and as differentially expressed among girls versus boys. [ABSTRACT FROM AUTHOR]