The 24-h movement behaviours composition is associated with parasympathetic modulation in preschoolers.

AIM: To investigate the associations between 24-h movement behaviours and heart rate variability (HRV) in preschool children. METHODS: A total of 123 preschoolers (4.52 ± 0.25 years old; 62 girls) were assessed for physical activity (PA) and sedentary behaviour (SB) using an accelerometer (Actigraph WGT3x). Sleep duration (SD) was parent-reported. Children were laid down in a supine position for 10 min to assess HRV data. The R-R intervals recorded during the last 5 min of this period were analysed. We conducted compositional analysis in R studio, and the significance level was 95%. All ethical procedures were followed, and the study had the approval of the local ethical board. RESULTS: When considered as a composition, adjusted for age, body mass index and sex, the 24-h movement composition (PA, SB and SD) significantly predicted better parasympathetic modulation (Root mean square of the successive differences [RMSSD] [p = 0.04; r2 = 0.13]), but not high frequency (HF) (nu) (p = 0.51, r2 = 0.01), low frequency (nu) (p = 0.52, r2 = 0.02),or standard deviation (standard deviation of normal-to-normal intervals) (p = 0.55, r2 = 0.02), respectively. CONCLUSION: These results suggest the 24-h movement composition predicted the RMSSD time-domain index related to parasympathetic activity.

Efficacy and safety of trigeminal parasympathetic pathway stimulation for dry eye: A systematic review and meta-analysis.

This study aimed to investigate the efficacy and safety of trigeminal parasympathetic pathway (TPP) stimulation in the treatment of dry eye. A comprehensive search for randomized clinical trials was performed in seven databases (MEDLINE, Embase, CENTRAL, etc.) up to 28 February 2023. After screening the suitable studies, the data were extracted and transformed as necessary. Data synthesis and analysis were performed using Review Manager 5.4, and the risk of bias and quality of evidence were evaluated with the recommended tools. Fourteen studies enrolling 1714 patients with two methods (electrical and chemical) of TPP stimulation were included. Overall findings indicate that TPP stimulation was effective in reducing subjective symptom score (standardized mean difference [SMD], -0.45; 95% confidence interval [CI], -0.63 to -0.28), corneal fluorescence staining (mean difference [MD], -0.78; 95% CI, -1.39 to -0.18), goblet cell area (MD, -32.10; 95% CI, -54.58 to -9.62) and perimeter (MD, -5.90; 95% CI, -10.27 to -1.53), and increasing Schirmer's test score (SMD, 0.98; 95% CI, 0.65 to 1.31) and tear film break-up time (SMD, 0.57; 95% CI, 0.19 to 0.95). Compared to inactive or low-activity stimulation controls, it has a higher incidence of adverse events. Therefore, TPP stimulation may be an effective treatment for dry eye, whether electrical or chemical. Adverse events are relatively mild and tolerable. Due to the high heterogeneity and low level of evidence, the current conclusions require to be further verified.

Childhood psychological maltreatment and social anxiety in college students: The roles of parasympathetic nervous system activity and parent-child separation experience.

BACKGROUND: Childhood psychological maltreatment is a risk factor for social anxiety in adulthood. Parent-child separation, as one of the most serious adversities in early life, may exacerbate the risk of psychological maltreatment and influence the interactions between childhood psychological maltreatment and biological sensitivity to stress in relation to social anxiety. However, there has been a dearth of work on this issue. OBJECTIVE: This study investigated the interactive effects between childhood psychological maltreatment and parasympathetic nervous system (PNS) activity on social anxiety in college students by comparing those who experienced parent-child separation versus those who did not. Potential sex differences in the aforementioned associations were tested as an exploratory aim. PARTICIPANTS AND SETTING: Data were obtained from 264 college students (Mage = 18.45 years, SD = 0.69), including 156 students who experienced parent-child separation and 108 students without this experience. METHODS: Participants completed measures of childhood psychological maltreatment and social anxiety and reported their parent-child separation experience. The data of PNS activity, measured by respiratory sinus arrhythmia (RSA) reactivity, were obtained during the Trier Social Stress Test (TSST) in the lab. RESULTS: Childhood psychological maltreatment was positively associated with college students' social anxiety. RSA reactivity moderated the relationship between childhood psychological maltreatment and college students' social anxiety, and the moderating role of RSA reactivity varied with parent-child separation experience and sex. CONCLUSIONS: Parent-child separation experience influenced the biosocial interactions between childhood psychological maltreatment and PNS activity in relation to individuals' social anxiety, and this effect persisted in adulthood.

The relationship between sustained attention and parasympathetic functioning.

Sustained attention (SA) is an important cognitive ability that plays a crucial role in successful cognitive control. Resting vagally-mediated heart rate variability (vmHRV) has emerged as an informative index of parasympathetic nervous system activity and a sensitive correlate of individual differences in cognitive control. However, it is unclear how resting vmHRV is associated with individual differences in sustained attention. The primary aim of the current study was to assess if resting vmHRV was associated with individual differences in performance on a neuropsychological assessment of sustained attention. We further aimed to characterize the relationship between resting vmHRV and dispositional factors related to sustained attention, specifically attentional errors in daily life, self-regulation, mindfulness and media-multitasking. Based on previous work, we hypothesized higher resting vmHRV would be associated with better sustained attention across task-based and self-report measures. We did not find resting vmHRV to be significantly associated with performance measures on a task-based assessment of sustained attention. Further, resting vmHRV was not significantly associated with attention errors, self-regulation, mindfulness, or media-multitasking. This work stands to expand the current understanding between parasympathetic functioning, cognition, and behavior, investigating the unexplored domain of sustained attention and related dispositional factors.

PEP reward reactivity moderates the effects of RSA reactivity on antisocial behavior and substance use.

Integrating Polyvagal Theory and Reinforcement Sensitivity Theory (RST), we examined pre-ejection period (PEP) reward reactivity, which was suggested to index trait impulsivity, as a moderator between respiratory sinus arrhythmia (RSA) reactivity and antisocial behavior (ASB), and substance use in an urban male, adult sample. To understand the inconsistent findings between RSA reactivity and externalizing problems, we proposed to study both negatively and positively valenced tasks for RSA reactivity and to include PEP reward reactivity as a moderator for the RSA-behavior link. Data were collected from an urban sample of 131 male adults (active offenders, demographic controls, and college students). ICG (impedance cardiography) and ECG (electrocardiogram) were recorded, computing PEP (sympathetic nervous system activity marker) and RSA (parasympathetic nervous system activity marker), while participants completed the modified Trier Social Stress Test and a simple reward task. Reactivity was calculated by subtracting the baseline from the task activity. Consistent with prior studies, more RSA withdrawal to stress and less PEP shortening to reward predicted the most ASB and substance use. Less RSA withdrawal to reward and more PEP shortening to reward predicted the most ASB and substance use. We incorporated autonomic space, RST, and Polyvagal Theory to discuss our findings, and specifically highlight how clarifying what each reactivity captures based on the task demand (e.g., presence of social threat, need for vagal-mediated social affiliative behavior) can illuminate our understanding of the result patterns.

Effects of prenatal opioid exposure on infant sympathetic and parasympathetic nervous system activity.

Prenatal opioid exposure has been associated with developmental problems, including autonomic nervous system dysregulation. However, little is known about the effects of prenatal opioid exposure on the autonomic nervous system beyond the first days of life, particularly across both the parasympathetic and sympathetic branches, and when accounting for exposure to other substances. The present study examined the effects of prenatal exposure to opioid agonist therapy (OAT, e.g., methadone) and other opioids on infant autonomic nervous system activity at rest and in response to a social stressor (the Still-Face Paradigm) at six months among 86 infants varying in prenatal opioid and other substance exposure. Results indicated that OAT and other opioids have unique effects on the developing autonomic nervous system that may further depend on subtype (i.e., methadone versus buprenorphine) and timing in gestation. Results are discussed in the context of theoretical models of the developing stress response system.

Respiratory sinus arrhythmia (RSA), vagal tone and biobehavioral integration: Beyond parasympathetic function.

Linchpin to the entire area of psychophysiological research and discussion of the vagus is the respiratory and cardiovascular phenomenon known as respiratory sinus arrhythmia (RSA; often synonymous with high-frequency heart-rate variability when it is specifically linked to respiratory frequency), i.e. rhythmic fluctuations in heart rate synchronized to inspiration and expiration. This article aims 1) to clarify concepts, terms and measures commonly employed during the last half century in the scientific literature, which relate vagal function to psychological processes and general aspects of health; and 2) to expand upon an earlier theoretical model, emphasizing the importance of RSA well beyond the current focus upon parasympathetic mechanisms. A close examination of RSA and its relations to the vagus may 1) dispel certain commonly held beliefs about associations between psychological functioning, RSA and the parasympathetic nervous system (for which the vagus nerve plays a major role), and 2) offer fresh perspectives about the likely functions and adaptive significance of RSA, as well as RSA's relationship to vagal control. RSA is neither an invariably reliable index of cardiac vagal tone nor of central vagal outflow to the heart. The model here presented posits that RSA represents an evolutionarily entrenched, cardiovascular and respiratory phenomenon that significantly contributes to meeting continuously changing metabolic, energy and behavioral demands.

Noncontact Evaluation Method for Autonomic Nervous System Activity during Exercise Using RGB Camera.

For efficient exercise, motor functions, heart rate, oxygen uptake (which are controlled by autonomic nervous system activity), heat acclimation-related functions, such as sweating, and thermoregulation must work properly during exercise. In this research, a noncontact method of measuring capillary contraction and dilation, one of the autonomic nervous system activities, using only a commercial web camera was developed. The absorption rate by haemoglobin in blood differs for each wavelength of light. When the capillaries in the face contract or dilate, the colour component of the light reflected from the face changes. The focus of this study was on the changes in the green and blue values of the face image. Green light reaches the dermis, where capillaries are located, while blue light reaches only the epidermis. The G/B ratio, the green value divided by the blue value, shows the changes in capillary contraction and dilation. An experiment was conducted to validate the G/B ratio method. Ten subjects (23 ± 1.6 years of age) participated in the experiment, and face movement and heart rate were measured during an aerobic bike exercise test. The results showed that, when the heart rate increased, the G/B ratio decreased immediately after the start of exercise. After the exercise stopped, the heart rate decreased immediately, and the G/B ratio increased. The G/B ratio revealed that the sympathetic nervous system became dominant during exercise, causing facial capillaries to dilate, and that the parasympathetic nervous system became dominant after exercise, causing facial capillaries to constrict.

Resting parasympathetic activity is associated with malodor-induced change in perceived foreignness of speakers.

INTRODUCTION: To protect against infection, individuals have evolved context-dependent pathogen-avoidant strategies, including selective social behaviors aimed at avoiding foreign individuals who may possess greater risk of infection. Parasympathetic nervous system (PNS) activity is associated with social engagement and regulation of the classical immune system but has not been widely investigated in relation to changes in intergroup perception and the behavioral immune system. METHOD: The current research investigated the relationship between parasympathetic activity and perceived foreignness of in and outgroup speakers during exposure to a pathogen-relevant odor (butyric acid). High-frequency heart rate variability was measured at rest and while participants rated foreignness of speakers with and without the odor present. RESULTS: Findings show that exposure to the odor was associated with higher foreignness perceptions of outgroup speakers and lower foreignness perceptions of ingroup speakers. This effect was especially evident among individuals with higher resting parasympathetic activity. CONCLUSION: These results suggest that the PNS may play a role in changes in social perceptions during a behavioral immune response.

Heart rate variability (HRV) as a way to understand associations between the autonomic nervous system (ANS) and affective states: A critical review of the literature.

Evidence suggests affective disorders such as depression and bipolar disorder are characterised by dysregulated autonomic nervous system (ANS) activity. These findings suggest ANS dysregulation may be involved in the pathogenesis of affective disorders. Different affective states are characterised by different ANS activity patterns (i.e., an increase or decrease in sympathetic or parasympathetic activity). To understand how ANS abnormalities are involved in the development of affective disorders, it is important to understand how affective states correlate with ANS activity before their onset. Using heart rate variability (HRV) as a tool to measure ANS activity, this review aimed to look at associations between affective states and HRV in non-clinical populations (i.e., in those without medical and psychiatric disorders). Searches on PubMed and Google Scholar were completed using the following search terms: heart rate variability, autonomic nervous system, sympathetic nervous system, parasympathetic nervous system, affective state, mood and emotion in all possible combinations. All but one of the studies examined (N = 13), demonstrated significant associations between affect and HRV. Findings suggest negative affect, encompassing both diffused longer-term experiences (i.e., mood) as well as more focused short-term experiences (i.e., emotions), may be associated with a reduction in parasympathetic activity as measured through HRV parameters known to quantify parasympathetic activity (e.g., high frequency (HF)-HRV). HRV measures typically linked to reduction in parasympathetic activity appear to be linked to negative affective states in non-clinical populations. However, given the complex and possibly non-linear relationship between HRV and parasympathetic activity, further studies need to clarify specificity of these findings. Future studies should investigate the potential utility of HRV measures as biomarkers for monitoring changes in affective states and for early detection of onset and relapse of depression in patients with affective disorders.

The Effect of Short-term Inhalation of Fir Essential Oil on Autonomic Nervous Activity in Middle-aged Women.

This study aimed to investigate the effect of short-term inhalation of fir essential oil on autonomic nervous activity in middle-aged women. Twenty-six women (mean age, 51.0 ± 2.9 years) participated in this study. The participants sat on a chair, closed their eyes, and inhaled fir essential oil and room air (control) for 3 min. A crossover trial was performed to eliminate the effect of the order of olfactory stimulation. Approximately half of the participants were administered stimuli in the following order: exposure to fir essential oil, then control. The remaining participants were administered control, followed by fir essential oil. Heart rate variability, heart rate, blood pressure, and pulse rate were used as indicators of the autonomic nervous system activity. The Semantic Differential method and Profile of Mood States were used as psychological indicators. The High Frequency (HF) value, an indicator of parasympathetic nerve activity reflecting a relaxed state, was significantly higher during stimulation with fir essential oil than during the control condition. The Low Frequency (LF)/(LF+HF) value, an indicator of sympathetic nerve activity reflecting awake state, was marginally lower during stimulation with fir essential oil than during the control condition. No significant differences were found in heart rate, blood pressure, and pulse rate. After inhaling fir essential oil, "comfortable," "relaxed," and "natural" feelings improved, negative moods decreased, and positive moods increased. In conclusion, inhalation of fir essential oil can help menopausal women in their physiological and psychological relaxation.

Awe Sparks Prosociality in Children.

Rooted in the novel and the mysterious, awe is a common experience in childhood, but research is almost silent with respect to the import of this emotion for children. Awe makes individuals feel small, thereby shifting their attention to the social world. Here, we studied the effects of art-elicited awe on children's prosocial behavior toward an out-group and its unique physiological correlates. In two preregistered studies (Study 1: N = 159, Study 2: N = 353), children between 8 and 13 years old viewed movie clips that elicited awe, joy, or a neutral (control) response. Children who watched the awe-eliciting clip were more likely to spend their time on an effortful task (Study 1) and to donate their experimental earnings (Studies 1 and 2), all toward benefiting refugees. They also exhibited increased respiratory sinus arrhythmia, an index of parasympathetic nervous system activation associated with social engagement. We discuss implications for fostering prosociality by reimagining children's environments to inspire awe at a critical age.

Rapid adjustments to autonomic control of cardiac rhythm at the onset of isometric exercise in healthy young adults.

Sympathetic nervous system (SNS) and parasympathetic nervous system (PNS) influences on cardiac rhythm at the onset of exercise, a time of rapid autonomic adjustments, are clinically important areas of investigation. Continuous wavelet transform (CWT) involves time-frequency-based heart rate variability (HRV) analysis allowing investigation of autonomic influences on cardiac rhythm during short durations of exercise. Therefore, the purpose of this study was to characterize SNS and PNS influences on cardiac rhythm at the onset of isometric exercise in healthy young adults. CWT analysis was retrospectively applied to R-R interval data (electrocardiogram) previously collected from 14 healthy young adults (26 ± 2 years) who performed 30-s, one-legged, isometric, calf exercise at 70% maximal voluntary contraction (MVC; 70% MVC trial) or rested (0% MVC trial). Absolute and normalized low-frequency (aLF, nLF; 0.04-0.15 Hz) and high-frequency (aHF, nHF; 0.15-0.4 Hz) bands and LF/HF were used to analyze one 30-s baseline period and six 5-s time windows during the 30-s exercise (70% MVC) or rest (0% MVC). Statistical analysis involved two-way analysis of variance with post-hoc analysis. aHF, aLF, LF/HF, nHF, and nLF displayed a trial-time interaction (all p ≤ 0.027). In the 70% compared to the 0% MVC trial, aHF and nHF were lower after 5-30 s (all p ≤ 0.040), aLF was lower after 20-30 s (all p ≤ 0.011) and LF/HF and nLF were higher after 5-20 s (all p ≤ 0.045). These results indicate the reduction of the PNS influence on cardiac rhythm begins sooner than the augmentation of the SNS influence at the onset of isometric exercise in healthy young adults.

A comparative evaluation of resting state proxies of sympathetic and parasympathetic nervous system activity in adolescent major depression.

Major depressive disorder (MDD) is associated with autonomic nervous system (ANS) dysfunction, characterized by decreased parasympathetic (PNS) and increased sympathetic (SNS) activity. Although findings on reduced PNS activity in adult MDD have been replicated in adolescents, comprehensive studies assessing PNS and SNS proxies in underage patients with MDD are scarce. Proxies of resting PNS (heart rate variability (HRV) and SNS activity (skin conductance response [SCR] and salivary alpha amylase [sAA], as well as mixed activity (heart rate [HR]) were collected in adolescents with MDD (n = 29) and non-depressed controls (n = 29). Primary analyses addressed differences between groups and correlations with depression severity. Patients with MDD showed significantly decreased HRV (g = - 0.87; 95% CI [- 1.39; - 0.35]) and increased HR (g = 0.66; 95% CI [0.14; 1.18]). Proxies of pure SNS activity showed no significant differences between groups. HR (positive) and HRV (negative) were significantly correlated with self- and clinician-rated depression severity. Alterations of ANS activity are evident in adolescent MDD, but characterized by decreased PNS activity only. We found no evidence for altered SNS activity. Findings suggest that ANS dysfunction early in the course of MDD might be predominantly driven by decreased PNS activity.

What to expect physiologically when you're expecting couples in therapy: A Changing Hearts and Minds in relationshiPS (CHAMPS) descriptive study.

Recent efforts to improve marital therapy interventions have begun investigating psychophysiologic processes in therapy. These studies are novel and represent initial investigations into relevant phenomena associated with the therapy process. Grounded in Polyvagal Theory, this study introduces an on-going multimethod couple therapy process research (CHAMPS) and highlights the importance of establishing norms among distressed couples in therapy, which can provide context for other studies' results and instigate further investigation of physiology in marital therapy. Using a sample of 24 married, heterosexual couples (N = 48), we examine trends in markers of sympathetic (SNS) and parasympathetic nervous system (PNS) functioning; namely, electrodermal activity (SNS), cardiac impedence (SNS), and respiratory sinus arrhythmia (PNS) before and during therapy sessions and shifts in these measures over the course of four therapy sessions. We discuss clinical implications and provide recommendations for further investigations.

Multisystem physiological reactivity during help-seeking for attachment needs in school-aged children: differences as a function of attachment.

In this study, we sought to expand on what is currently known regarding autonomic nervous system (ANS) reactivity in middle childhood as a function of attachment. ANS activity includes multiple indices - respiratory sinus arrhythmia (RSA) is an index of parasympathetic nervous system activation (PNS) and electrodermal activity (EDA) is an index of sympathetic nervous system activation (SNS). Children (N = 103) completed Child Attachment Interviews and read vignettes describing situations aimed to activate attachment needs (NEED; e.g., getting hurt, which can elicit need for comfort or assistance) and help-seeking (HS; when children experience need and seek comfort from attachment figures), while SNS and PNS reactivity were monitored. Attachment was not associated with children's SNS or PNS reactivity during NEED, but attachment was associated with physiological reactivity during HS: Dismissing attachment was associated with greater SNS activation (higher EDA) and preoccupied attachment with PNS deactivation (lower RSA, greater vagal withdrawal) during HS.

Emotional and autonomic response to visual erotic stimulation in patients with functional hypothalamic amenorrhea.

Introduction: Functional hypothalamic amenorrhea (FHA) is a clinical condition associated with high levels of physiological and psychological stress ranging from weight loss to maladaptive behavior and coping skills. A reliable measure of the psychophysiological response to stress and the ability to cope with stimuli is heart rate variability (HRV). Through the sympathetic (SNS) and parasympathetic nervous system (PNS), the autonomic nervous system (ANS) promotes various changes in HRV that reflect the individual's psychophysiological response to stress. FHA patients are characterized by high levels of PNS activation during psychological load, suggesting that parasympathetic hyperactivation could be a pathology marker. Methods: In the present study, we examine changes in HRV during observation of erotic, neutral, and disgusting images in 10 patients with FHA [(mean ± S.D.) age: 26.8 ± 5.9] and in 9 controls (age: 25.4 ± 6.4; BMI: 22.47 ± 2.97) to assess the differential activation of PNS and SNS between FHA patients and controls matched for age and without other clinical conditions. Results: Our results showed that FHA patients had significantly higher HRV activation while observing high emotional value images and not during the observation of neutral images confirming a parasympathetic hyperactivation. Discussion: HRV and cognitive and psychological testing, could provide new insights into understanding such a clinically understudied condition and provide further tools for clinical diagnosis and treatment.

The psychophysiological mechanisms of real-world time experience.

Our sense of time is fallible, often resulting in the sensation of time flying by quickly or dragging slowly. It has been suggested that changes in sympathetic (SNS) and parasympathetic nervous system (PNS) activity may influence the perceived passage of time, however this proposition has never been tested during real-world temporal experience. The current study directly tested the relationship between the passage of time and SNS-PNS activity in the real-world. Sixty-seven participants completed a normal day's activities whilst wearing sensors to capture electrocardiography (ECG), electrodermal activity (EDA) and movement. They also provided hourly rating of the subjective speed at which time was passing. Results revealed that greater SNS activity (e.g., increased heart rate, frequency of phasic skin conductance response) was associated with time passing more quickly. PNS activity was not related to time experience. Whilst the findings support previous suggestions that changes in physiological arousal are associated with distortions to the passage of time, the effects are small and other factors are likely to contribute to real-world temporal experience.

Molecularly defined circuits for cardiovascular and cardiopulmonary control.

The sympathetic and parasympathetic nervous systems regulate the activities of internal organs1, but the molecular and functional diversity of their constituent neurons and circuits remains largely unknown. Here we use retrograde neuronal tracing, single-cell RNA sequencing, optogenetics and physiological experiments to dissect the cardiac parasympathetic control circuit in mice. We show that cardiac-innervating neurons in the brainstem nucleus ambiguus (Amb) are comprised of two molecularly, anatomically and functionally distinct subtypes. The first, which we call ambiguus cardiovascular (ACV) neurons (approximately 35 neurons per Amb), define the classical cardiac parasympathetic circuit. They selectively innervate a subset of cardiac parasympathetic ganglion neurons and mediate the baroreceptor reflex, slowing heart rate and atrioventricular node conduction in response to increased blood pressure. The other, ambiguus cardiopulmonary (ACP) neurons (approximately 15 neurons per Amb) innervate cardiac ganglion neurons intermingled with and functionally indistinguishable from those innervated by ACV neurons. ACP neurons also innervate most or all lung parasympathetic ganglion neurons-clonal labelling shows that individual ACP neurons innervate both organs. ACP neurons mediate the dive reflex, the simultaneous bradycardia and bronchoconstriction that follows water immersion. Thus, parasympathetic control of the heart is organized into two parallel circuits, one that selectively controls cardiac function (ACV circuit) and another that coordinates cardiac and pulmonary function (ACP circuit). This new understanding of cardiac control has implications for treating cardiac and pulmonary diseases and for elucidating the control and coordination circuits of other organs.

Context is key: Parasympathetic regulation in the classroom differentially predicts preschoolers' socially competent behaviors.

Research shows that children's early social competence predicts their later academic and interpersonal success. Accordingly, early childhood education programs increasingly aim to evaluate and support children's social skill development. Despite ample theoretical and empirical work demonstrating the role of the parasympathetic nervous system (PNS) in supporting neurophysiological processes that underlie social behaviors, no study has explicitly tested whether the assessment of PNS activity in childhood educational settings provides insight into children's social functioning. The current study addresses this gap by examining the influence of context-specific PNS regulation, assessed via respiratory sinus arrhythmia (RSA), in predicting preschool children's socially competent behavior toward peers in the classroom. Results showed that: (1) RSA withdrawal (e.g., decreases relative to a baseline task) during unstructured classroom activities predicted children's socially competent behaviors during these unstructured activities but not during structured activities, whereas (2) withdrawal during structured classroom activities predicted children's socially competent behaviors during structured activities. These results indicate that PNS activity makes context-specific contributions to children's social behaviors and highlight the importance of assessing neurophysiological regulation in context.