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Cooperation, as a mutual collaboration, is a defining feature of human social life. Individual characteristics can influence cooperation. Recent studies have shown a quadratic relationship between cardiac vagal tone (CVT), an index of self‐regulation, and prosocial behaviors. Individual differences in cooperation might also vary as a function of people's environmental sensitivity (ES), i.e., may be influenced by individual differences in the perception and processing of inner and external stimuli. We tested the direct and interactive effect of CVT and ES on cooperative behaviors in two independent samples. We measured heart rate and engagement in cooperative acts in 80 young adults (M = 23.61; SD = 1.60) who were also asked to self‐report on ES. We found an inverted‐U relationship between CVT and cooperative behaviors. ES, on the other hand, did not predict differences in cooperative behaviors but moderated the relationships between CVT and cooperation, although the magnitude of this result was small. Specifically, only among individuals with higher ES cooperative behaviors change as a function of CVT. Highly sensitive individuals with lower or higher CVT, were less cooperative than low sensitive ones. Subsequently, we replicated the same study design in a second sample of 88 undergraduate students (M = 23.69; SD = 4.91). Once again, we found evidence supporting the presence of an inverted‐U relationship between CVT and cooperative behaviors, and we also found that ES moderated the relationships between the quadratic CVT term and cooperation. Our findings add new evidence on physiological self‐regulation as an underlying mechanism of prosocial behaviors, in particular cooperation. In two independent samples, our results showed a quadratic relationship between cardiac vagal tone (CVT) and cooperation. We found that this relationship is moderated by environmental sensitivity (ES). Specifically, only among individuals with higher ES, cooperative behaviors change as a function of CVT. To make the world more cooperative, people should learn how to regulate especially when they are highly sensitive. [ABSTRACT FROM AUTHOR]

Studies have shown a significant association between effective parasympathetic modulation of the heart and processes linked to social cognition. Particularly, Quintana and colleagues documented a relation between vagally‐mediated heart rate variability (vmHRV) and performance on a theory of mind (ToM) task, namely, the Reading the Mind in the Eyes Test (RMET), in a sample of university students. The purpose of the present study was to test whether such result would extend to a sample of school‐aged children (7–9 years old) using the child version of the RMET. In addition, the Eyes Test Revised was administered as it is more suitable to evaluate ToM during childhood. Results supported the positive association between vmHRV and ToM abilities, replicating and extending previous results obtained in young adults. The current study adds to the existing literature pointing to HRV as a putative biomarker of social cognition abilities. [ABSTRACT FROM AUTHOR]

Cooperation is crucial in classrooms for positive interactions among pupils, but the factors influencing children's cooperative behaviors remain debated. This study explores the impact of cardiac vagal tone (CVT), a measure of physiological self-regulation, and cognitive control on cooperation among 109 primary school students. Heart rate variability was used to assess self-regulation, and cognitive control was evaluated through an AX-Continuous Performance Task. Cooperative behavior was measured with a child-friendly Stag Hunt game. Results showed that moderate CVT is related to increased cooperative actions, but no direct relationship between cognitive control types and cooperation was found. However, an interaction effect indicated that moderate CVT particularly boosts cooperation in children who employ proactive cognitive control. These findings emphasize the need to develop physiological self-regulation skills to enhance cooperative behavior in educational settings, supporting better social, and emotional well-being, and learning outcomes. [ABSTRACT FROM AUTHOR]

In sports, physical recovery following exercise‐induced fatigue is mediated via the reactivation of the parasympathetic nervous system (PNS). A noninvasive way to quantify the reactivation of the PNS is to assess vagally‐mediated heart rate variability (vmHRV), which can then be used as an index of physical recovery. This systematic review and meta‐analysis investigated the effects of physical recovery techniques following exercise‐induced fatigue on vmHRV, specifically via the root mean square of successive differences (RMSSD). Randomized controlled trials from the databases PubMed, WebOfScience, and SportDiscus were included. Twenty‐four studies were part of the systematic review and 17 were included in the meta‐analysis. Using physical post‐exercise recovery techniques displayed a small to moderate positive effect on RMSSD (k = 22, Hedges' g = 0.40, 95% confidence interval [CI] = 0.20–0.61, p = 0.04) with moderate heterogeneity. In the subgroup analyses, cold water immersion displayed a moderate to large positive effect (g = 0.75, 95% CI: 0.42–1.07) compared with none for other techniques. For exercise type, physical recovery techniques performed after resistance exercise (g = 0.69, 95% CI: 0.48–0.89) demonstrated a larger positive effect than after cardiovascular intermittent (g = 0.52, 95% CI: 0.06–0.97), while physical recovery techniques performed after cardiovascular continuous exercise had no effect. No significant subgroup differences for training status and exercise intensity were observed. Overall, physical post‐exercise recovery techniques can accelerate PNS reactivation as indexed by vmHRV, but the effectiveness varies with the technique and exercise type. [ABSTRACT FROM AUTHOR]

Background: Self‐regulation promotes engagement within the classroom. At a physiological level, a good indicator of the ability of the system to self‐regulate is cardiac vagal tone (CVT). Aims: The present study aims to assess children's change over time (1 year) in their parasympathetic regulation (by way of CVT) in response to a social and cognitive stressor. Moreover, it addresses whether, if present, this change over time in regulation influences students' engagement in classroom activities while also accounting for classroom climate. Sample: Forty‐nine second graders were assessed at two time points: November 2018 (T1) and 1 year later in 2019 (T2). Methods: Children's CVT was registered at rest and while performing a stressful task during which they were asked to cognitively perform while being socially evaluated. Children were also interviewed on how much they feel engaged in classroom activities and their perceptions of classroom climate. Results: A repeated measures analysis of variance including 2 Time Points ×2 Phases of CVT Registration (baseline and during the stressful task) revealed a significant decrease in cardiac vagal activity from baseline to the task at T1, indicating that initially most children were not able to self‐regulate and gave way to a stress response when facing the stressful task. The pattern changed at T2 when an active regulation took place signalled by an increase in CVT from baseline to the stressful task. Data analysis also revealed that among children who perceived a poorer classroom climate, the display of greater parasympathetic regulation over time was linked with higher active engagement in classroom activities. Conclusions: Growth in physiological regulation in response to a challenging task is associated with better engagement in classroom activities. Interventions and educational practice promoting the development of self‐regulation strategies are recommended. [ABSTRACT FROM AUTHOR]

Sinus node dysfunction is a multifaceted disorder with variable manifestations, the prevalence of which increases with age. In a specific group of patients, excessive vagal activity may be the sole cause for this condition. These patients are characterized as having recurrent daytime symptoms attributed to bradyarrhythmia, no evidence of organic sinus node lesions, cardiac vagal overactivation, and are non-elderly. For sinus node dysfunction patients, a permanent pacemaker implantation appears to be the ultimate solution, although it is not an etiological treatment. Cardioneuroablation is a promising emerging therapy that can fundamentally eliminate symptoms in a highly selective sub-set of sinus node dysfunction patients by cardiac vagal nerve denervation. Denervation with ablation for vagal-induced sinus node dysfunction can effectively improve sinus bradycardia and reduce syncope. To date, guidelines for selection of suitable candidates for cardioneuroablation remain lacking. The primary objective of this study was to distinguish the nature of abnormal sinus node function and to find methods for quantifying vagal tone. Clear selection criteria could help physicians in identification of patients with autonomic imbalance, thereby maximizing patient benefits and the success rate of cardioneuroablations. [ABSTRACT FROM AUTHOR]

Objectives: Engaging in meditation seems to be an effective manner of bettering psychosocial health. Although these findings hold for most people, individual differences may affect who gets greater gains from meditation. Psychological (i.e., resilience, spirituality) and biological (i.e., cardiac vagal tone, oxytocin) personal resources may work individually or synergistically to catalyze meditation-related improvements in mental health, such as increased positive (well-being) and decreased negative (depression) mental health symptoms. Methods: A community-based sample of 210 adults (modeage = 35 years; 61.86% female) were recruited and randomly assigned to either mindfulness (n = 107; 51.2%) or loving-kindness (n = 102; 48.8%) meditation conditions (1 missing). The study lasted 18 months, starting with baseline measures, succeeded by a 6-week meditation intervention, and follow-up assessments every 3 months. Results: The fixed effect of resilience was significant, as was the interaction between resilience and time, indicating different mental health symptom trajectories during and after a meditation intervention based on resilience. Conclusions: Participants low in resilience tended to have the greatest gains (increased subjective well-being and decreased depressive symptoms) following a meditation intervention, yet these gains were not maintained 18 months following the intervention. Those high in resilience did not show mental health gains following a meditation intervention but did have higher subjective well-being symptoms 18 months following the intervention indicating that they may have experienced delayed gains. [ABSTRACT FROM AUTHOR]

This cross-sectional study explored whether the association between perceived family support and child well-being was moderated by the individual trait of Environmental Sensitivity (the ability to register, process, and respond to stimuli) and cardiac vagal tone (CVT, an index of self-regulation) in a sample of children living in socioeconomically disadvantaged families. Participating children (N = 131, M age = 7.20 years, 47% boys) were individually interviewed about the support received within the family as well as their physical and emotional well-being. Children's sensitivity was assessed via a series of behavioral tasks, and CVT was recorded at rest. Hierarchical cluster analysis on the behavioral items yielded three sensitivity groups: "Low sensitive" (43%), "Moderately sensitive" (33%), and "Highly sensitive" (24%). The three groups of children did not differ in baseline CVT. However, linear regression analyses revealed that at low and average levels of family support, highly sensitive children with higher resting CVT reported better well-being than those with low resting CVT, whereas no effect was observed among children in the other two groups. In the context of high family support, children reported high levels of well-being irrespective of their levels of vagal activity or sensitivity. The findings suggest that among low SES families, when children experience a poorly supportive family environment and are highly sensitive to negative experiences, having a higher resting CVT may confer an advantage in terms of well-being. Implications for theory and practice are discussed. [ABSTRACT FROM AUTHOR]

Early stressful events negatively affect emotional and physical well‐being. Cardiac vagal tone (CVT), which is associated with better emotional and physical well‐being, usually gradually increase in early childhood. Nonetheless, children's CVT developmental trajectories are greatly variable, such that CVT can increase or decrease across the years. The present study examines the longitudinal effects of early stressful events and the role of 4 years CVT developmental trajectory on children's emotional and physical well‐being. Forty‐two 4‐year‐old children were enrolled. Number of stressful events and resting electrocardiogram (ECG) were collected at T1. ECG was registered again after one (T2), two (T3) and three (T4) years. Children's emotional and physical well‐being were assessed at T4 through the Child Health and Illness Profile – Child Edition (CHIP–CE). CVT development was calculated as the angular coefficient, reflecting the developmental trajectory of CVT across the four timepoints. Results yielded that higher experienced stressful events predicted poorer emotional and physical well‐being after 4 years. The interaction between the number of stressful events and CVT development emerged on physical well‐being. Early stressful events negatively affect long‐term children's emotional and physical well‐being while a positive CVT development seems to mitigate the negative effects of early stressful events on physical well‐being. [ABSTRACT FROM AUTHOR]

Background: As the COVID-19 pandemic continues, determining hospital demands has become a vital priority. Heart rate variability (HRV) has been linked to both the presence of viral infection and its severity. We investigate the possibility of using HRV parameters in comparison to other clinical parameters for predicting the hospital length of stay (LOS) for COVID-19 patients. Methods: This was a population-based cohort study. Measurements were performed in a specialized hospital for respiratory disease, dedicated to COVID-19. Patients were polymerase chain reaction positive for COVID-19 and on their 1st day of admission. Heart period, respiratory sinus arrhythmia (RSA), low frequency (LF) HRV, and vagal efficiency were calculated from electrocardiogram signals. This study investigated the correlation of HRV, demographic, and laboratory parameters with hospital LOS. Results: Forty-one participants were recruited, with a significant relationship, observed between hospital LOS and some demographic and clinical parameters such as lymphocyte count, age, and oxygen saturation of arterial blood. There was a negative relationship between LF and hospital LOS (r = −0.53, 95% confidence interval: −0.73, −0.24). Higher vagal efficiency predicted shorter hospital LOS in patients younger than 40 years of age (19.27% shorter hospital LOS was associated with a one SD higher value of VE, P = 0.007). Conclusion: HRV measurement is a non-invasive, inexpensive, and scalable procedure that produces several metrics, some of which are useful for predicting hospital LOS and managing treatment resources during COVID-19 pandemic. [ABSTRACT FROM AUTHOR]

Purpose: This experimental cross-sectional research study examined the emotional reactivity and emotion regulation in preschool-age children who do (CWS) and do not stutter (CWNS) by assessing their psychophysiological response during rest and while viewing pictures from the International Affective Picture System (Lang et al., 2008). Method: Participants were 18 CWS (16 boys and two girls; mean age 4 years, 5 months) and 18 age- and gender-matched CWNS. Participants' psychophysiological responses were measured during two baselines and two picture viewing conditions. Skin conductance level (SCL) and heart rate were measured to assess emotional reactivity. Respiratory sinus arrhythmia (RSA) was measured to assess emotional regulation. Participants' shyness and executive function were assessed via parent report and considered for their effects on participants' psychophysiological responses. Results: First, CWNS and CWS did not differ in their initial baseline SCL, heart rate, or RSA, but all participants had higher SCL and lower RSA in the second baseline, subsequent to the first challenge condition, compared to the first baseline. Second, during the challenge conditions, CWS did not differ from CWNS in their SCL, but showed a significantly higher heart rate than CWNS. Third, CWS exhibited a significantly lower RSA during the challenge conditions compared to CWNS. Lastly, the temperamental quality of shyness was associated with preschool-age children's SCL, such that participants who were rated higher in shyness had a higher SCL during the challenge conditions. Participants' executive function had a marginally significant effect on the RSA, such that the participants who had higher executive function composite scores exhibited lower RSA during the challenge conditions. Conclusions: Our findings suggest that CWS and CWNS did not differ in their emotional reactivity and emotional regulation abilities at rest. During challenge conditions, however, CWS tended to be more emotionally reactive, as indicated by a higher heart rate, and also employed more emotional regulation, indexed by a greater decrease in RSA, compared to CWNS. Preschool-age children's behavior is largely dominated by reactivity, but there is the emergence of regulation, which can help children adjust to various contextual demands. For CWS who are more emotionally reactive, regulatory skills may be particularly critical to their prognosis and treatment. [ABSTRACT FROM AUTHOR]

The current surge of interest in postural orthostatic tachycardia syndrome commonly known as POTS requires good knowledge of the very complex physiology involved, but this is currently lacking. The often overlooked normal physiology of orthostasis is reviewed including the definition of normal postural orthostatic tachycardia. An illustrated functional anatomy that embeds orthostatic tachycardia within the learned and skilful motor functions in the human population is presented. The four physiological phases of orthostasis and the role of tachycardia are described in a laboratory‐controlled and progressive orthostatic stress in normal human volunteers. Standardized surrogate measures of autonomic control were used to quantify the trigger level for excessive tachycardia and the minimum autonomic control required to sustain viable arterial blood pressure during severe orthostatic stress in normal human volunteers. Tachycardia during orthostasis is part of a "democratic" contribution by four cardiovascular parameters of which the chronotropic function of the heart is just one of the parameters contributing toward cardiovascular compensation. It is adjusted during orthostasis in proportion to contributions from the other three parameters, namely inotropic function of the heart, windkessel vascular resistance and venous vascular capacitance. The physiological effects of the two stressors during orthostasis, gravity and isometric contraction of skeletal muscles are reviewed. A model of how the four cardiovascular parameters are regulated during orthostasis to achieve proportionate contributions is proposed emphasizing the necessity to quantify individual contributions from all these four parameters. Any one or more of these parameters may be compromised due to disease requiring disproportionate contribution of the prevailing magnitude of orthostatic tachycardia in an individual. It therefore requires neurophysiological assessment of the autonomic regulation of all the four cardiovascular parameters to assess the condition fully. We recommend here some current and novel neurophysiological methods that use modern medical technology to quantify laboratory standardized surrogate measures of some of these cardiovascular parameters including central parasympathetic regulation in postural orthostatic tachycardia syndrome. [ABSTRACT FROM AUTHOR]

Objectives: Heart rate variability (HRV) is a physiological marker of health with higher values representing a more efficient autonomic nervous system (ANS), which is responsible for maintaining and regulating the body's organs. Higher HRV is also associated with self-regulation and skills necessary to manage thoughts, emotions, and goals. HRV theoretically overlaps with neurobiological mechanisms associated with mindfulness training, particularly those located in neural regions involved in self-regulation. Due to this association, HRV has become an increasingly utilized biomarker in mindfulness-based intervention (MBI) research. Yet, the utility of HRV in MBI research has not been thoroughly examined nor substantiated. In this scoping review, we aim to determine how HRV has been assessed and analyzed in the MBI literature. We attempt to synthesize relevant findings while highlighting variability in the assessment of HRV across MBI studies. Methods: We conducted a search of Google Scholar, PsycINFO, and PubMed databases, which yielded 17 original MBI studies (11 experimental and 6 quasi-experimental) that included HRV assessment. Results: Among the more rigorously designed and executed studies, we identified an increase in HRV reactivity (corresponding to adaptive changes of HRV in response to a task/stressor) following implementation of an MBI among non-clinical samples. Conclusions: Although review findings support the utility of HRV as an objective biomarker capable of demonstrating MBI effects, more research is needed to address the high variability in methods across studies. We discuss major limitations and offer recommendations for future research utilizing HRV measurement in MBI research trials. [ABSTRACT FROM AUTHOR]

Evolutionary-based predictions imply that the premenstrual syndrome (PMS) affects women who failed to conceive while in biosocial conditions that allow immediate reproduction. We investigated how the PMS is related to the heart rate variability (HRV), a marker of general fitness and well-being. The HRV indices (SDNN and rMSSD) were calculated using resting ECGs of 113 physiologically fertile women and 64 women using hormonal contraception (HC users, HCu). The intensity of PMS symptoms was self-assessed (Shortened Premenstrual Assessment Form). Analyses were conducted using parametric and nonparametric tests and general linear modelling (GLM). In HC non-users (HCnu), a greater intensity of PMS symptoms was significantly associated with higher values of HRV. Similar relations were not present in HCu. Post-hoc GLM confirmed that the relation between the PMS intensity and HRV indices varies as a function of the HCu status. A positive association between the PMS intensity and high HRV indices in women who did not use HC may confirm that the PMS affects fertile women who did not conceive, despite being in conditions favorable to pregnancy. The absence of a similar link in HCu women implies that synthetic steroids may disturb the link between the PMS and functioning of the autonomic nervous system. [ABSTRACT FROM AUTHOR]

The neurovisceral integration model proposes that heart rate variability (HRV) is linked to prefrontal cortex activity via the vagus nerve, which connects the heart and the brain. HRV, an index of cardiac vagal tone, has been found to predict performance on several cognitive control tasks that rely on the prefrontal cortex. However, the link between HRV and the core cognitive control function “shifting” between tasks and mental sets is under-investigated. Therefore, the present study tested the neurovisceral integration model by examining, in 90 participants, the relationship between vagally mediated resting-state HRV and performance in a task-switching paradigm that provides a relatively process-pure measure of cognitive flexibility. As predicted, participants with higher resting-state HRV (indexed both by time domain and frequency domain measures) showed smaller switch costs (i.e., greater flexibility) than individuals with lower resting-state HRV. Our findings support the neurovisceral integration model and indicate that higher levels of vagally mediated resting-state HRV promote cognitive flexibility. [ABSTRACT FROM AUTHOR]

The use of heart rate variability (HRV) to inform daily training prescription is becoming common in endurance sport. Few studies, however, have investigated the use of pre-training HRV to predict decreased performance or altered exercising autonomic response, typical of functional overreaching (FOR). Further, a new cardiac vagal tone (ProCVT) technology purports to eliminate some of the noise associated with daily HRV, and therefore may be better at predicting same-day performance. The purpose of this investigation was to examine if changes to resting HRV and ProCVT were associated with alterations in performance, maximal heart rate (HRmax), or heart rate recovery (HRrec) in FOR athletes. Twenty-eight recreational cyclists and triathletes were assigned to experimental/control conditions and underwent: 1 week of reduced training, 3 weeks of overload (OL) or regular training (CON), and 1 week of recovery. Testing occurred following the reduced training week (T1), post-3 weeks of training (T2), and following the recovery week (T3). Measures of resting HRV/ProCVT were collected each testing session, followed by maximal incremental exercise tests with HRrec taken 60 s post-exercise. Performance decreased from T1 to T2 in the OL group vs. CON (Δ−9 ± 12 vs. Δ9 ± 11 W, P < .001), as did HRmax (Δ−8 ± 4 vs. Δ−2 ± 4 bpm, P < .001). HRrec increased from T1 to T2 in the OL group vs. CON (Δ10 ± 9 vs. Δ2 ± 5 beats/min, P < .01). HRV and ProCVT did not change in either group. Same-day resting autonomic measures are insufficient in predicting alterations to performance or exercising HR measures following overload training.  [ABSTRACT FROM AUTHOR]

Patients suffering from dissociative disorders are characterized by an avoidance of aversive stimuli. This includes the avoidance of emotions and, in particular, bodily perceptions. In the present pilot study, we explored the potential interoceptive accuracy deficit of patients suffering from dissociative disorders in a heartbeat detection task. Moreover, we investigated the impact of facial mirror-confrontation on interoceptive accuracy and the potential association between cardiac vagal tone derived from heart rate variability and interoceptive accuracy. Eighteen patients suffering from dissociative disorders and 18 healthy controls were assessed with the Mental Tracking Paradigm by Schandry for heartbeat detection at baseline and after confrontations exposing them to their own faces in a mirror (2 min each, accompanied by a negative or positive cognition). During the experiment, cardiac vagal tone was assessed. We used Pearson correlations to calculate potential associations between cardiac vagal tone and interoceptive accuracy. Patients performed significantly worse than the healthy controls in the heartbeat detection task at baseline. They displayed no significant increase in interoceptive accuracy following facial mirror-confrontation. In the patient group, higher cardiac vagal tone was associated with a more precise heartbeat detection performance. Dissociative disorder patients showed a considerable deficit in interoceptive accuracy. Our results fit with the assumption that highly dissociative patients tend to tune out the perceiving of bodily signals. To the extent that bodily signal perception may play a causal role in these disorders, therapeutic approaches enhancing interoceptive accuracy and cardiac vagal tone may be considered important and practicable steps to improve the therapy outcome of this patient group. [ABSTRACT FROM AUTHOR]

The autonomic nervous system (ANS) is a brain body interface which serves to maintain homeostasis by influencing a plethora of physiological processes, including metabolism, cardiorespiratory regulation and nociception. Accumulating evidence suggests that ANS function is disturbed in numerous prevalent clinical disorders, including irritable bowel syndrome and fibromyalgia. While the brain is a central hub for regulating autonomic function, the association between resting autonomic activity and subcortical morphology has not been comprehensively studied and thus was our aim. In 27 healthy subjects [14 male and 13 female; mean age 30 years (range 22-53 years)], we quantified resting ANS function using validated indices of cardiac sympathetic index (CSI) and parasympathetic cardiac vagal tone (CVT). High resolution structural magnetic resonance imaging scans were acquired, and differences in subcortical nuclei shape, that is, 'deformation', contingent on resting ANS activity were investigated. CSI positively correlated with outward deformation of the brainstem, right nucleus accumbens, right amygdala and bilateral pallidum (all thresholded to corrected P < 0.05). In contrast, parasympathetic CVT negatively correlated with inward deformation of the right amygdala and pallidum (all thresholded to corrected P < 0.05). Left and right putamen volume positively correlated with CVT (r = 0.62, P = 0.0047 and r = 0.59, P = 0.008, respectively), as did the brainstem ( r = 0.46, P = 0.049). These data provide novel evidence that resting autonomic state is associated with differences in the shape and volume of subcortical nuclei. Thus, subcortical morphological brain differences in various disorders may partly be attributable to perturbation in autonomic function. Further work is warranted to investigate these findings in clinical populations. Hum Brain Mapp 39:381-392, 2018. © 2017 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

This study investigated the role of basal cardiac activity and inhibitory control at the beginning of the school year in predicting oral comprehension at the end of the year in pre-schoolers. Forty-three, 4-year-olds participated in the study. At the beginning of the school year children's electrocardiogram at rest was registered followed by the assessment of inhibitory control as well as verbal working memory and verbal ability. At the end of the year all children were administered a listening comprehension ability measure. A stepwise regression showed a significant effect of basal cardiac vagal tone in predicting listening comprehension together with inhibitory control and verbal ability. These results are among the first to show the predictive role of basal cardiac vagal tone and inhibitory control in pre-schoolers' oral text comprehension, and offer new insight into the association between autonomic regulation of the heart, inhibitory control, and cognitive activity at a young age. [ABSTRACT FROM AUTHOR]

The goal of the present study was to examine how quality of the child–caregiver attachment relationship related to children’s cardiac vagal reactivity in response to a novel social stressor. Children’s (N= 48;Mage= 3 years 9 months) cardiac data were collected as they participated in an ambiguous and potentially threatening social situation together with their mothers. Their degree of behavioral inhibition also was observed. Attachment classifications were assessed separately. Children classified as Secure showed vagal withdrawal from baseline to the stressor, whereas children classified as Ambivalent did not show vagal withdrawal in response to the stressor. There was a marginally significant moderation of attachment-related differences in vagal withdrawal by level of behavioral inhibition. Among highly behaviorally inhibited children, those classified as Ambivalent demonstrated little or no vagal withdrawal compared to their Secure counterparts. In contrast, no attachment-related differences were found among those who appeared less behaviorally inhibited. Findings are discussed in relation to children’s emerging self-regulation skills in the context of their attachment relationship. [ABSTRACT FROM PUBLISHER]

Background The parasympathetic nervous system has been implicated in the pathogenesis of a number of gastrointestinal disorders including irritable bowel syndrome. Within the field, cardiometric parameters of parasympathetic/vagal tone are most commonly derived from time, or frequency, domain analysis of heart rate variability (HRV), yet it has limited temporal resolution. Cardiac vagal tone (CVT) is a non-invasive beat-to-beat measure of brainstem efferent vagal activity that overcomes many of the temporal limitations of HRV parameters. However, its normal values and reproducibility in healthy subjects are not fully described. The aim of this study was to address these knowledge gaps. Methods 200 healthy subjects (106 males, median age 28 years, range 18-59 years) were evaluated across three study centers. Aft er attachment of CVT recording equipment, 20 min of data (resting/no stimulation) was acquired. 30 subjects, selected at random, were restudied aft er 1 year. Results The mean CVT was 9.5±4.16 linear vagal scale (LVS). Th us, the normal range (mean±2 standard deviations) for CVT based on this data was 1.9-17.8 LVS. CVT correlated negatively with heart rate (r=-0.6, P=0.001). CVT reproducibility over 1 year, as indexed by an intra-class correlational coefficient of 0.81 (95% confidence interval 0.64-0.91), was good. Conclusions In healthy subjects, the normal range for CVT should be considered to be 1.9-17.8 LVS and is reproducible over 1 year. Future research utilizing CVT should refer to these values although further study is warranted in patient groups. [ABSTRACT FROM AUTHOR]

We examined the relationship between tonic-a correlate of self-regulatory functioning-and phasic cardiac vagal activity (indexed by heart rate variability; HRV) during a selective attentional task with varying levels of load. Participants detected a target letter among letter strings superimposed on either fearful or neutral face distractors. Letter strings consisted of six target letters under low load and one target letter and five nontarget letters under high load. With fearful distractors, lower tonic HRV was associated with phasic HRV suppression, suggesting an autonomic stress response under both low and high load. In contrast, higher tonic HRV was associated with phasic HRV enhancement, suggesting greater self-regulatory effort under low load and an absence of phasic HRV suppression under high load. The current research suggests that tonic cardiac vagal tone is associated with the ability to flexibly adapt autonomic responses. [ABSTRACT FROM AUTHOR]

The neurovisceral integration model (Thayer and Lane, 2000) posits that cardiac vagal tone, indexed by heart rate variability (HRV), can indicate the functional integrity of the neural networks implicated in emotion?cognition interactions. Our recent findings begin to disentangle howHRV is associated with both top-down and bottom-up cognitive processing of emotional stimuli. Higher resting HRV is associated with more adaptive and functional top-down and bottom-up cognitive modulation of emotional stimuli, which may facilitate effective emotion regulation. Conversely, lower resting HRV is associated with hypervigilant and maladaptive cognitive responses to emotional stimuli, which may impede emotion regulation. In the present paper, we recapitulate the neurovisceral integration model and review recent findings that shed light on the relationship between HRV and topdown and bottom-up visual perception and attention to emotional stimuli, which may play an important role in emotion regulation. Further implications of HRV on individualwell-being and mental health are discussed. [ABSTRACT FROM AUTHOR]

A previous study has shown that greater cardiac vagal tone, reflecting effective self-regulatory capacity, was correlated with superior visual discrimination of fearful faces at high spatial frequency Park et al. (Biological Psychology 90:171-178, ). The present study investigated whether individual differences in cardiac vagal tone (indexed by heart rate variability) were associated with different event-related brain potentials (ERPs) in response to fearful and neutral faces. Thirty-six healthy participants discriminated the emotion of fearful and neutral faces at broad, high, and low spatial frequencies, while ERPs were recorded. Participants with low resting heart rate variability-characterized by poor functioning of regulatory systems-exhibited significantly greater N200 activity in response to fearful faces at low spatial frequency and greater LPP responses to neutral faces at high spatial frequency. Source analyses-estimated by standardized low-resolution brain electromagnetic tomography (sLORETA)-tended to show that participants with low resting heart rate variability exhibited increased source activity in visual areas, such as the cuneus and the middle occipital gyrus, as compared with participants with high resting heart rate variability. The hyperactive neural activity associated with low cardiac vagal tone may account for hypervigilant response patterns and emotional dysregulation, which heightens the risk of developing physical and emotional problems. [ABSTRACT FROM AUTHOR]

The experience of child maltreatment is a known risk factor for the development of psychopathology. Structural and functional modifications of neural systems implicated in stress and emotion regulation may provide one mechanism linking early adversity with later outcome. The authors examined two well-documented biological markers of stress vulnerability [resting frontal electroencephalogram (EEG) asymmetry and cardiac vagal tone] in a group of adolescent females exposed to child maltreatment (n = 38; M age = 14.47) and their age-matched non-maltreated (n = 25; M age = 14.00) peers. Maltreated females exhibited greater relative right frontal EEG activity and lower cardiac vagal tone than controls over a 6-month period. In addition, frontal EEG asymmetry and cardiac vagal tone remained stable in the maltreated group across the 6 months, suggesting that the neurobiological correlates of maltreatment may not simply reflect dynamic, short-term changes but more long lasting alterations. The present findings appear to be the first to demonstrate stability of two biologically based stress-vulnerability measures in a maltreated population. Findings are discussed in terms of plasticity within the neural circuits of emotion regulation during the early childhood period and alternative causal models of developmental psychopathology. © 2009 Wiley Periodicals, Inc. Dev Psychobiol 51: 474–487, 2009 [ABSTRACT FROM AUTHOR]

We examined aspects of emotional empathy across different physiological response systems in boys with disruptive behavior disorders (DBD) and normal controls. Heart rate (HR) and electromyographic (EMG) reactivity in zygomaticus major and corrugator supercilii muscles were monitored during sadness-, anger-, or happiness-inducing film clips. Relative to controls, DBD boys showed significantly less HR reduction during sadness, and a smaller increase in corrugator EMG activity both during sadness and anger. No significant group differences emerged in HR and zygomaticus EMG responsivity during happiness. We also examined cardiac activity at rest and found higher resting HR and lower respiratory sinus arrhythmia in DBD boys compared to controls. Findings give evidence for a selective impairment in empathy with sadness and anger (not happiness) among DBD boys who exhibit relatively high levels of anxiety and poor emotional control. [ABSTRACT FROM AUTHOR]

Relations between maternal postpartum behavior and the emergence of parent-infant relatedness as a function of infant autonomic maturity were examined in 56 premature infants (birthweight = 1000–1500 g) and 52 full-term infants. Maternal behavior, mother depressive symptoms, and infant cardiac vagal tone were assessed in the neonatal period. Infant–mother and infant–father synchrony, maternal and paternal affectionate touch, and the home environment were observed at 3 months. Premature birth was associated with higher maternal depression, less maternal behaviors, decreased infant alertness, and lower coordination of maternal behavior with infant alertness in the neonatal period. At 3 months, interactions between premature infants with their mothers and fathers were less synchronous. Interaction effects of premature birth and autonomic maturity indicated that preterm infants with low vagal tone received the lowest amounts of maternal behavior in the postpartum and the least maternal touch at 3 months. Infant–mother and infant–father synchrony were each predicted by cardiac vagal tone and maternal postpartum behavior in both the preterm and full-term groups. Among preterm infants, additional predictors of parent–infant synchrony were maternal depression (mother only) and the home environment (mother and father). Findings are consistent with evolutionary perspectives on the higher susceptibility of dysregulated infants to rearing contexts and underscore the compensatory mechanisms required for social-emotional growth under risk conditions for parent–infant bonding. © 2007 Wiley Periodicals, Inc. Dev Psychobiol 49: 290–302, 2007. [ABSTRACT FROM AUTHOR]

Perpetrators of domestic violence describe symptoms that are compatible with exaggerated autonomic arousal at the time of the domestic violence. This inappropriate arousal may be reflected in altered heart rate regulation. If heart rate is systematically regulated by vagal mechanisms, then increases in heart rate should correlate with decreases in cardiac vagal activity, as indexed by respiratory sinus arrhythmia (RSA). We hypothesized that perpetrators of domestic violence have an alteration in heart rate regulation. To test this hypothesis we compared the results of a postural shift performed on perpetrators, healthy volunteers, and nonviolent alcoholics. Results showed there were no significant differences in heart rate, RSA, or catecholamines. However, the significant inverse relationship between posture-elicited changes in RSA and heart rate present in the healthy volunteers was not found in perpetrators. These differences in the covariation between heart rate and RSA may represent differences in the neural regulation of heart rate and may be related to difficulties in controlling autonomic state. [ABSTRACT FROM AUTHOR]

Abstract The goal of the present study was to test a recent hypothesis that the ability to suppress cardiac vagal tone during a cognitive challenge was related to social behavior. One hundred thirty-six infants participated with their parents in laboratory visits when infants were 12 (mother visit) and 13 months (father visit) of age. To measure the infants' regulation of cardiac vagal tone, heart rate responses were recorded during the administration of a test of mental development (father visit). Responses to a stranger interaction were measured during the 12 month visit. In addition, experimenters evaluated the infants' behavior across the laboratory sessions using an adaptation of the Infant Behavior Record. Results revealed that infants who were able to suppress vagal tone during the cognitive challenge were rated by the experimenters as more socially approaching at the two laboratory visits. Vagal regulation was unrelated to behavior during the stranger-infant interaction. These findings partially support the hypothesis that infants who are able to regulate their vagal tone have a greater capacity for social engagement. [ABSTRACT FROM AUTHOR]

Ontogenesis of both vagal control of heart rate and the baroreceptor vagal reflex were evaluated in rats at postnatal ages (P) of 5/6, 10, 15, 20, 25 and >42 days anaesthetised with urethane (1.5 g/kg). Between P5/6 and P25 heart rate rose from 372 ± 12 to 448 ± 20 beats per minute and mean arterial pressure increased from 33.9 ± 3.1 to 74.59 ± 3.25 mm Hg (mean ± SEM, n = 7 and 11 respectively). Cardiac vagal tone was absent at P10 but significant at P20 ( P < 0.05) as revealed with atropine (0.5–1 mg/kg i.v.). Baroreceptor cardiac reflex sensitivity, tested with phenylephrine (10–50 μg/kg i.v.), was attenuated significantly in P10–20 rats compared with P5/6, P25 and mature animals. In P14–17 rats stimulation of neurones in either the solitary tract or ambiguual nuclei, by microinjection of L-glutamate (100–200 pmol), evoked an atropine-sensitive bradycardia indicating a functional integrity of central and peripheral efferent pathways mediating the baroreceptor reflex. Thus, the baroreceptor vagal reflex is functional in P5/6 rats but becomes attenuated between P10–P20, which is coincident with the maturational rise in arterial pressure. [ABSTRACT FROM AUTHOR]

Infants' preferences for a novel or familiar nursery rhyme were examined as an index of long-term memory. One- to 2-month-old infants' preferences were tested, using a nonnutritive sucking discrimination-learning procedure, at 1, 2, or 3 days after the last of multiple familiarization sessions. A consistent novelty preference was observed at the 1-day retention interval, no consistent preference occurred at the 2-day interval, and a familiarity preference was found following the 3-day interval. This pattern of results is consistent with attentional preference models which interpret novelty and familiarity preferences as reflecting the discrepancy between an external stimulus and the infant's representation of the stimulus. The findings also reveal that infants as young as 1 month of age encoded and subsequently recognized a repeatedly experienced nursery rhyme after a 3-day retention interval. [ABSTRACT FROM AUTHOR]

Dose-dependent effects of intravenously administered lorazepam on haemodynamic fluctuations were studied by means of spectral analysis, in order to elucidate sympathetic and parasympathetic components in cardiovascular control during situations of rest and mental stress after benzodiazepine administration. In a double-blind randomized cross-over study, nine male volunteers participated in two sessions: a placebo and lorazepam session. During these sessions, the subjects repeatedly performed a 10-min version of the Stroop Color Word Test (CWT), with 10 min of rest between the CWTs. Lorazepam was administered before each rest period in increasing doses of 0.0, 0.06, 0.13, 0.25 and 0.5 mg (total cumulative dose: 0.94 mg). During the placebo session the subjects received five placebo injections. For five of the nine subjects the lorazepam session was their first session. Heat rate (HR), blood pressure (BP) and respiration were recorded continuously. Power spectra were calculated per 2.5-min periods for HR, systolic (SBP) and diastolic BP (DBP). Spectral density was assessed for three frequency bands: low (LFB: 0.02-0.06 Hz), mid (MFB: 0.07-0.14 Hz) and high (HFB: 0.15-0.40 Hz). During the consecutive periods of rest, lorazepam induced a dose-dependent decrease in HR, and a dose-dependent increase in LFB, MFB and HFB power of HR, but lorazepam had no effect on BP. The effects were significant after 0.44 mg lorazepam for HR and HFB power, and after 0.94 mg lorazepam for the HR fluctuations in the LFB and MFB. Lorazepam did not influence the cardiovascular responses to the CWT. Our data underline that benzodiazepines can exert a specific influence on parasympathetic activity: lorazepam induced dose-dependent increases in cardiac vagal tone, resulting in decreased HR and increased HR variability, but only during periods of rest. The increase in vagal tone observed after low doses of lorazepam was not related to diminished sympathetic activity, altered respiration, or increased sedation. [ABSTRACT FROM AUTHOR]

Respiratory sinus arrhythmia (RSA) is frequently employed as an intra- and interindividual index of cardiac parasympathetic tone, although the relationship or RSA to interindividual differences in cardiac vagal tone remains questionable. Our study examined between- and within-subject relations among RSA, cardiac vagal tone, and respiratory parameters. Twenty-nine young adults performed two sessions of tasks under no medication and single and double autonomic blockade (intravenously administered propranolol and atropine). Parasympathetic tone was determined from heart period responses to complete vagal blockade. Results indicated the following. Resting RSA does not accurately predict individual differences in cardiac vagal tone. However, RSA and heart period together do predict such individual differences reasonably well. The relationship between individual variations in RSA and vagal tone is not improved by controlling respiratory parameters. Substantial cardiac vagal activity occurs during inspiration, and intraindividual variations in respiratory measures confound the association between RSA and cardiac vagal tone. [ABSTRACT FROM AUTHOR]

Twenty-three healthy men and women participated in a 5-session experiment in which they attempted to increase and decrease their heart rate with the assistance of visual analogue biofeedback. As a group subjects did successfully raise and lower heart rate from resting baseline. These changes in heart rate were closely paralleled by changes in &Vcirc;, a measure of cardiac vagal tone. Heart rate slowing was associated with increases in &Vcirc;, and heart rate speeding was associated with decreases in &Vcirc;. Respiration rate and amplitude did not differ significantly between heart rate slowing and speeding trials, and covariance analysis indicated that respiratory changes did not account for the heart rate or &Vcirc; effects. The weighted coherence between respiration and heart rate showed that cardiopulmonary coupling increased during heart rate slowing and decreased during heart rate speeding. Individual differences in cardiac vagal tone and cardiopulmonary coupling were unrelated to heart rate speeding and slowing performance. [ABSTRACT FROM AUTHOR]

This study addresses it number of unresolved issues regarding the employment of respiratory sinus arrhythmia as an Index of tonic parusympathetic cardiac control in psychophysiological investigations. These questions include the following: (1) Does respiratory sinus arrhythmia reflect cardiac vagal tone under conditions in which alterations in parasympathetic control are expected to be mild to moderate? (2) Are variations in human respiratory sinus arrhythmia that occur in response to varying behavioral demands independent of beta-adrenergic effects on the heart? (3) To what extent do typical experimental tasks apparently affect tonic cardiac vagal control? Twelve healthy male subjects were administered a Joint alpha- and β-adrenoreceptor pharmacological blocker on one day and a placebo on another (balanced across subjects). On both days, respiratory sinus arrhythmia and heart period were monitored during a number of different experimental tasks while subjects continuously paced their respiration. Results indicated that respiratory sinus arrhythmia, under controlled respiratory conditions, is uninfluenced by variations in sympathetic activity, and provides , reasonably sensitive index of cardiac vagal tone. even when alterations in parasympathetic tone are not large. Furthermore, our findings suggest that cardiac vagal tone is responsive to varying behavioral demands and may interact in different ways with β-adrenergic mechanisms. [ABSTRACT FROM AUTHOR]

A recent meta-analysis revealed that cardiac vagal activity (mostly indicated by vagally-mediated heart rate variability; HRV) decreases significantly from the follicular to luteal menstrual cycle phase in naturally-cycling participants. However, the question remains as to whether cyclical changes in estradiol (E2), progesterone (P4), or both are responsible for HRV fluctuations. We present the first studies to use repeated measures of E2, P4, and HRV across the cycle to model both the unique and interactive effects of person-centered E2 and P4 on HRV in multilevel models. In study one, 40 naturally-cycling participants were assessed weekly across four weeks, and were blind to the cycle focus of the study. In study two, 50 naturally-cycling participants were examined in three precisely defined cycle phases via ovulation testing. Both studies revealed that only P4 was correlated with HRV, such that higher-than-usual P4 significantly predicted lower-than-usual HRV within a given participant. In line with this, cycle phase comparisons revealed lower HRV in the mid-luteal phase (characterized by elevated P4) than in other phases. No significant main or interactive effects of E2 on HRV were found. Future female health studies should investigate individual differences in these effects and potential consequences of cyclical HRV changes on daily functioning. [ABSTRACT FROM AUTHOR]

Interest in cardiac vagal activity (CVA; e.g., parasympathetically-mediated heart rate variability) as a biomarker of physical and mental health has increased exponentially in recent years. However, the understanding of sources of within-person change (i.e., intra-individual variance) in CVA is lagging behind. This systematic review and meta-analysis summarizes and quantifies current empirical evidence of within-person changes in measures of CVA across the menstrual cycle in naturally-cycling premenopausal females. We conducted an extensive literature search following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement in five databases to identify observational studies with repeated measures of CVA in at least two menstrual cycle phases. A broad meta-analysis (nstudies = 37; nindividuals = 1,004) revealed a significant CVA decrease from the follicular to luteal phase (d = −0.39, 95% CI (−0.67, −0.11)). Furthermore, 21 studies allowed for finer-grained comparisons between each of two cycle phases (menstrual, mid-to-late follicular, ovulatory, early-to-mid luteal, and premenstrual). Significant decreases in CVA were observed from the menstrual to premenstrual (nstudies = 5; nindividuals = 200; d = −1.17, 95% CI (−2.18, −0.17)) and from the mid-to-late follicular to premenstrual phases (nstudies = 8; nindividuals = 280; d = −1.32, 95% CI (−2.35, −0.29)). In conclusion, meta-analyses indicate the presence of CVA fluctuations across the menstrual cycle. Future studies involving CVA should control for cycle phase. Recommendations for covarying or selecting cycle phase are provided. [ABSTRACT FROM AUTHOR]

Breathing techniques are part of traditional relaxation methods; however, their influence on psychophysiological variables related to sleep is still unclear. Consequently, the aim of this paper was to investigate the influence of a 30-day slow-paced breathing intervention compared to social media use on subjective sleep quality and cardiac vagal activity (CVA, operationalized via high-frequency heart rate variability). Healthy participants (n = 64, 33 male, 31 female, M = 22.11, SD = 3.12) were randomly allocated to an experimental or control group. In the experimental group, they had to perform slow-paced breathing for 15 min each evening across a 30-day period. This was administered through a smartphone application. The control group used social media (e.g., Facebook, Instagram, Whatsapp) for the same duration. The night before and after the intervention, their CVA was assessed via a light portable Electrocardiogram (ECG) device, and they had to fill out the Pittsburgh Sleep Quality Index questionnaire. Results showed that in comparison to the use of social media, the slow-paced breathing technique improved subjective sleep quality and increased overnight CVA, while a tendency was observed for morning awakening CVA. Slow-paced breathing appears a promising cost-effective technique to improve subjective sleep quality and cardiovascular function during sleep in young healthy individuals. [ABSTRACT FROM AUTHOR]