The polyvagal theory: phylogenetic substrates of a social nervous system

Multimodal interpersonal synchrony: Systematic review and meta-analysis

This systematic review and meta-analysis examined the interplay among neural, physiological, and behavioral interpersonal synchrony. We included studies written in English, comprising human dyads, and reporting data that could be translated to correlation estimates between at least two modalities of synchrony, sourced from PsycINFO, PubMed, and Google Scholar. The initial meta-analysis, examining associations between neural and behavioral synchrony, assessed 37 samples with 1342 participants, revealed a significant medium effect size (r = 0.32, 95 %CI: [0.23, 0.41]) with higher correlations in studies measured frontocentral regions and used the same epoch size for synchrony calculations. The analysis on associations between physiological and behavioral synchrony included 13 samples (369 participants) and identified small effect size (r = 0.18, 95 %CI: [0.06, 0.30]). Due to the limited sample size of three studies involving 150 participants, we conducted a systematic review rather than a meta-analysis to examine the relationship between neural and physiological synchrony. This review revealed inconsistent results, underscoring the need for further research. Future inquiries address greater multimodal integration in certain brain regions and measures, such as frontal and central regions. A theoretical framework that will explain multimodal integration of synchrony will allow us to ascertain if it is a unique aspect of social experiences, or simply a description of synchrony across levels of organization.

Vagally-mediated heart rate variability longitudinally predicts test anxiety in university students

BACKGROUND AND OBJECTIVES

Self-regulatory processes, namely behavioral regulation (in terms of executive functions) and emotion regulation, are assumed to be central for test anxiety. Both self-regulation components, along with vagally-mediated heart rate variability (HRV) - a proposed concomitant of top-down self-regulation - are associated with anxiety.

DESIGN

A longitudinal design was adopted to test the hypotheses that (1) higher vagally-mediated HRV, (2) adaptive emotion regulation and (3) better executive functioning (i.e., higher inhibitory control) at the semester beginning (t1) predict lower levels of test anxiety at the end of the semester (t2).

METHODS

A sample of N = 70 (58 female) university students (M [SD] age = 25.04 [7.14] years) completed a measurement of resting HRV (RMSSD), performed an affective go/no-go task, and reported on emotion regulation and test anxiety at t1. Test anxiety and certain examination characteristics were assessed at t2. A hierarchical regression analysis was conducted to test the hypotheses.

RESULTS

Supporting hypothesis 1, HRV at t1 significantly predicted test anxiety at t2, whereas emotion regulation and inhibitory control were no significant predictors.

CONCLUSIONS

As vagally-mediated HRV seems meaningful for the prediction of test anxiety, interventions designed to reduce test anxiety could benefit from incorporating HRV biofeedback training.

How does oxytocin modulate human behavior?

While the highly evolutionarily conserved hypothalamic neuropeptide, oxytocin (OT) can influence cognitive, emotional and social functions, and may have therapeutic potential in disorders with social dysfunction, it is still unclear how it acts. Here, we review the most established findings in both animal model and human studies regarding stimuli which evoke OT release, its primary functional effects and the mechanisms whereby exogenous administration influences brain and behavior. We also review progress on whether OT administration can improve social symptoms in autism spectrum disorder and schizophrenia and consider possible impediments to translational success. Importantly, we emphasize that OT acting via its extensive central or peripheral receptors primarily influences behavior indirectly through neuromodulatory interactions with classical transmitters and other peptides which themselves can independently influence behavior. We also emphasize that exogenous administration studies increasingly demonstrate peripheral effects of OT may be of greater importance than originally thought, especially involving the vagus. Overall, we propose a hierarchical model whereby OT's neuromodulatory actions influence behavior across interconnected functional domains and ultimately help to promote survival, security and sociability. Initially, OT potently facilitates attention to salient social and other important stimuli and additionally modulates cognitive, emotional and reward processing in a person- and context-dependent manner to promote interpersonal social understanding, attraction and bonds on the one hand and social group cohesion through increased conformity, altruistic punishment and moral emotions on the other. OT also increases co-operation and protection across both social domains. We hope this review and model will promote further research and help aid future translation success.

Decreased risk-proneness with increasing age in equally raised and kept wolves and dogs

A basic mechanism of domestication is the selection for fearlessness and acceptance of humans as social partners, which may affect risk-taking behavior and the ability to use humans as social support, both at the behavioural and physiological levels. We combined behavioural observations with heart rate parameters (i.e., HR and heart rate variability, HRV) in equally raised and housed wolves and dogs to assess the responses to food offered in the vicinity of a potential stressor (an unknown spinning object) with and without social support from a familiar human. Based on previous studies on neophobia in wolves and dogs, we expected dogs to be less scared of the object, approach more quickly, show less ambivalent behaviour, lower HR, and higher HRV, than wolves, especially at the presence of a human partner. However, we found that mainly age and the presence of a familiar human affected the behaviour of our subjects: older wolves and dogs were generally bolder and faster to approach the food and the familiar human's presence increased the likelihood of taking it. HR rate parameters were affected by age and the stage of the test. Wolves and dogs showed particularly high HRs at the beginning and end of the test sessions. We conclude that in our paradigm, wolves' and dogs' risk-proneness varied with age, rather than species. Additionally, the presence of a familiar human increased the motivation of both, dogs and wolves to take the food.

Protocol to implement and evaluate a culturally secure, strength-based, equine-assisted learning program, "Yawardani Jan-ga" (horses helping), to support the social and emotional wellbeing of Australian aboriginal children and young people

Australian Aboriginal people experience stressors from inequalities across crucial social determinants, including deep and entrenched disadvantage and exclusion. The impact of unaddressed historical issues is pervasive and intergenerational. The disproportionate rates of Aboriginal youth suicide, juvenile detention and imprisonment highlight the inadequacy of existing social and emotional wellbeing programs and services for Aboriginal children and young people. There is increasing recognition in Australia that aligning social and emotional wellbeing interventions with Western values and conceptions of mental health is one of the main barriers to service uptake among Aboriginal people. This suggests fundamental questions remain unanswered about what type of services effectively address the complex constellation of social-emotional and wellbeing challenges arising from intergenerational poverty and trauma. Yawardani Jan-ga is an Aboriginal-led, operated, culturally secure, Equine-Assisted Learning (EAL) project designed by and with local Aboriginal young people, community Elders, members, and experts to address the complex constellation of social-emotional, spiritual and wellbeing needs of Aboriginal children and young people, aged 6-26 years, across multiple communities in the Kimberley region of Western Australia. EAL is a strengths-based learning approach where participants work with horses' inherent characteristics to learn transferable life skills, such as communication skills, self-awareness, and emotional regulation, to promote social and emotional growth and wellbeing. Although EAL has been previously used with Aboriginal children and young people internationally, they are yet to be widely used with Aboriginal people in Australia. Here, we describe the three subcomponents of the Yawardani Jan-ga implementation science project and the planned Participatory Action Research and phenomenological approaches to capture the distinctive experiences of participants and the local communities where the intervention is implemented. We anticipate that findings will build an evidence base that informs policy and practice by understanding key intervention elements of social and emotional wellbeing support for Aboriginal youth, how to incorporate Aboriginal worldviews across different stages of interventions, and how to capture impact best using culturally secure methods.

Neurophysiology of adaptative and maladaptive stress: Relations with psychology of stress

OBJECTIVES

The stress reaction is an integrated response to a change in the environment that enables each individual to adapt to demand. While this response is physiologically coordinated by the brain, its phenomenology is expressed in the field of psychology and psychopathology. This interrelation between neurophysiological mechanisms and psychological processes is complex as dynamic interpersonal, biological, and psychocognitive systems interact with contextual and environmental factors to shape adaptation over the life constraints.

METHOD

This article aims to present the actors of the adjusted stress response, such as coping and coping flexibility, mindfulness and resilience, and their respective neurophysiology.

RESULTS

A model of the relationship between resilience, mindfulness and coping was proposed for optimizing adaptation to stress response.

DISCUSSION

These focuses are prerequisites for understanding and supporting human adaptation in the everyday environment and promoting efficient management of stress for mental and physical health.

Teacher stress in social interactions in the light of polyvagal theory. An ambulatory assessment approach to teachers' heart rate and heart rate variability

Background

Teaching is a genuinely social and highly demanding task. Drawing on Porges' phylogenetic polyvagal theory with three evolved systems and three associated behavioral responses (social engagement, mobilization, and immobilization), we investigated teachers' heart rate and heart rate variability in social interactions using ambulatory assessments.

Methods

We continuously measured heart rate and heart rate variability of 42 apparently healthy teachers on a work and leisure day with ambulatory electrocardiogram. We videotaped four consecutive, same-day lectures of each teacher. We trained observers to code student aggression and frontal teaching behaviors in an event sampling procedure with the behavior observation system for analyzing aggressive behavior in school settings. Additionally, perceived teacher-student relationship, social support from other teachers / school management, occupational complaints, and vital exhaustion were assessed by teacher self-reports.

Results

Teachers showed an increased heart rate and a decreased heart rate variability on a workday compared to a leisure day, anticipatory stress before classes, as well as insufficient recovery during lunchtime. Observed student aggression and high proportion of frontal teaching were associated with lower heart rate variability, while better perceived teacher-student relationship was correlated with higher heart rate variability. Differently, teachers' psychological strain and heart rate variability were unrelated to each other.

Conclusion

Corresponding to polyvagal theory, results suggest that successful social interactions are fundamental for teachers' favorable cardiological reactions.

Altered vocal communication in adult vasopressin-deficient Brattleboro rats

The neuropeptide, arginine vasopressin (AVP), has been implicated in social communication across a diverse array of species. Many rodents communicate basic behavioral states with negative versus positive valence through high-pitched vocalizations above the human hearing range (ultrasonic vocalizations; USVs). Previous studies have found that Brattleboro (Bratt) rats, which have a mutation in the Avp gene, exhibit deficits in their USVs from the early postnatal period through adolescence, but the magnitude of this effect appears to decrease from the juvenile to adolescent phase. The present study tested whether Bratt rats continue to exhibit USV deficits in adulthood. USVs of adult male and female Bratt and wild type (WT) rats were recorded in two contexts: a novel environment (empty arena) and a social context (arena filled with bedding soiled by same-sex conspecifics). The number, frequency, and duration of 50 kHz USVs were quantified by DeepSqueak after validation with manual scoring. Twenty-two kHz measures were quantified by manual scoring because DeepSqueak failed to accurately detect USVs in this frequency range. Adult Bratt rats did not exhibit deficits in the number of 50 kHz USVs: male Bratt rats emitted similar 50 kHz USVs as male WT rats, whereas female Bratt rats emitted more USVs than female WT rats. USV frequency and duration were altered in adult Bratt rats, but in a context-dependent manner. Twenty-two kHz USVs were less affected by the Bratt mutation. The present study demonstrates how chronic AVP deficiency impacts social communication across the lifespan. The present findings reveal a complex role for AVP in vocal communication, whereby disruption to the Avp gene leads to sex-, context-, and developmental phase-specific effects on the quantity and spectrotemporal characteristics of rat USVs.

Cardiac autonomic regulation as a proxy of early neurodevelopment: A systematic review

BACKGROUND

Cardiac autonomic regulation and early neurodevelopment are linked, but research has focused largely on specific domains, such as attention and memory, neglecting broad neurodevelopmental outcomes. The use of diverse study populations and methodologies further hinders interpretation, highlighting the need for more consistent, integrative research in this area. Therefore, the aim of this study was to clarify how cardiac autonomic regulation (as quantified by heart rate indices) is associated with global neurodevelopment in infancy through a systematic literature review.

METHOD

A systematic literature search was carried out in the Scopus, PubMed, Web of Science, and ProQuest databases for studies published between January 1980 and December 2022. The search terms were a combination of words that included elements from three categories: 1) cardiac vagal regulation, 2) neurodevelopment indicators, and 3) population (neonate/infant).

RESULTS

Five studies involving 933 infants (48 % of whom were girls) and baseline evaluations from birth to 26 weeks of age were included. The findings were mixed: while some studies identified positive associations between parasympathetic activity and neurodevelopmental outcomes, others reported nonsignificant or inconsistent associations. The variability in study designs, measurement methods, and population characteristics likely contributed to these discrepancies. However, respiratory sinus arrhythmia (RSA) was the most commonly used indicator, and the highest percentage of studies reported significant associations between neurodevelopment and autonomous functioning (RSA = 83 %, heart rate variability = 69 %), particularly when controlling for factors such as age and birthweight.

CONCLUSIONS

Although autonomic regulation during the first years of life appears to be associated with neurodevelopment, the evidence is not entirely consistent across all heart rate indices or developmental domains. Further research is needed to better understand these relationships, particularly in light of the methodological differences and potential confounding factors. Recognizing individual differences in autonomic nervous system regulation could provide valuable insights into neurodevelopmental trajectories.

Coupling Up: A Dynamic Investigation of Romantic Partners' Neurobiological States During Nonverbal Connection

Nonverbal connection is an important aspect of everyday communication. For romantic partners, nonverbal connection is essential for establishing and maintaining feelings of closeness. EEG hyperscanning offers a unique opportunity to examine the link between nonverbal connection and neural synchrony among romantic partners. This current study used an EEG hyperscanning paradigm to collect frontal alpha asymmetry (FAA) signatures from 30 participants (15 romantic dyads) engaged in five different types of nonverbal connection that varied based on physical touch and visual contact. The results suggest that there was a lack of FAA while romantic partners were embracing and positive FAA (i.e., indicating approach) while they were holding hands, looking at each other, or doing both. Additionally, partners' FAA synchrony was greatest at a four second lag while they were holding hands and looking at each other. Finally, there was a significant association between partners' weekly negative feelings and FAA such that as they felt more negative their FAA became more positive. Taken together, this study further supports the idea that fleeting moments of interpersonal touch and gaze are important for the biological mechanisms that may underlie affiliative pair bonding in romantic relationships.

Individual differences in parasympathetic nervous system reactivity in response to everyday stress are associated with momentary emotional exhaustion

Acute stressors (e.g., time pressure) can provoke psychological and physiological stress responses, and the magnitude of such responses is called stress reactivity. However, stress reactivity levels can differ considerably among individuals, with exaggerated levels being associated with adverse outcomes (e.g., emotional exhaustion). Previous studies have primarily investigated psychological stress reactivity or physiological stress reactivity induced in the laboratory. Physiological stress reactivity, especially concerning heart rate variability (HRV), has rarely been examined so far in real life. We addressed this research gap in a sample of 394 adults who participated in 2- to 4-day ecological momentary assessments. Individuals answered self-reports on perceived time pressure and emotional exhaustion multiple times a day and simultaneously wore electrocardiogram sensors. Based on 4,009 total situations and 3-16 situations per participant, individual differences in HRV reactivity to time pressure were computed as random slopes from multilevel models. Consistent with preregistered hypotheses, increased time pressure was associated with reduced HRV, and increased stress reactivity was associated with increased emotional exhaustion. The findings highlight the detrimental effects of everyday demands and physiological reactivity and emphasize the relevance of practical coping strategies. This study contributes to research on dynamic inter- and intraindividual stress regulation using ambulatory, psychophysiological methods.

A Comprehensive Investigation of Social Anxiety and Social Evaluative Stress in Autistic Children and Adolescents and Specific Learning Disorders

The aim was to investigate trait social anxiety and social evaluative stress in autistic children and adolescents and Specific Learning Disorders (SLD). This was done by evaluating behavioral, subjective, and autonomic responses to the Trier Social Stress Test (TSST). Study 1 included 280 children and adolescents: 60 autistic without intellectual disability (ID), 70 SLD, and 150 non-diagnosed (ND) peers. Study 2 involved 55 participants: 15 autistic without ID, 15 SLD, and 20 ND. The sample was predominantly male. In Study 1, behavioral (quality of public speech) and subjective (valence, arousal, perceived competence, and worries) aspects of social stress were examined. Study 2 expands upon the first study, as physiological responses to social stress were also measured. Trait social anxiety was investigated using both parents' and children's reports in the two studies. Parents of autistic participants and with SLD reported higher trait social anxiety in their children than the parents of ND. No differences emerged from the participants' self-reports, though those autistic and with SLD were assigned lower scores in the public speech quality than ND. Autistic children and adolescents reported lower arousal and higher perceived competence than ND, while those with SLD reported a lower perception of competence. Autistic participants had a decreased cardiac reactivity across the TSST when compared to SLD and ND. Our findings show unique patterns of responses within each group, confirming that the combined investigation of trait anxiety and social stress responses could be a valuable insight in research and clinical practice.

Autonomic assessment at the intersection of psychosocial and gastrointestinal health

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.

Multimodal transcutaneous auricular vagus nerve stimulation: An option in the treatment of sleep bruxism in a "polyvagal" context

OBJECTIVE

To consider the possible role of the vagus nerve (VN) in the pathophysiology of sleep bruxism (SB) and introduce a multimodal protocol of transcutaneous auricular stimulation of the VN in the treatment of SB patients.

METHODS

Ten patients with SB underwent four sessions of electric transcutaneous auricular vagus nerve stimulation (ta-VNS) in specific auricular areas. The patients were advised to manually stimulate the same areas between sessions. Masticatory muscle activity and sleep parameters were measured by a polysomnography (PSG) before and after the treatment. Heart rate variability (HRV) parameters were measured during each stimulation.

RESULTS

PSG analysis revealed a statistically significant reduction in tonic SB index and tonic contraction time. HRV parameters showed a statistically significant increase in mean values of the vagal tone after each session of stimulation. No side effect was reported.

CONCLUSION

The stimulation of the VN might have a role in the treatment of SB.

Associations between intraindividual reaction time variability, baseline respiratory sinus arrhythmia, and trait impulsivity in males with substance use disorders

Trait impulsivity, characterized by the tendency to act without adequate consideration of potential consequences in pursuit of immediate rewards, is a recognized vulnerability marker for substance use disorders (SUDs). Cognitive control deficits are implicated in the manifestation of high trait impulsivity, and intraindividual reaction time variability (IIRTV), an indicator of cognitive control, may influence trait impulsivity. Baseline respiratory sinus arrhythmia (RSA) reflects vagal tone, serves as an index of physiological self-regulation, which has been demonstrated to be related to trait impulsivity. However, it is unclear whether IIRTV is associated with trait impulsivity and whether it interacts with baseline RSA to influence trait impulsivity. A total of 113 males with SUDs participated (Mage = 46.04 years, SD = 11.53) in this study. Trait impulsivity was assessed using a self-report questionnaire, IIRTV was measured through a two-choice oddball task, and baseline RSA was obtained through the collection of electrocardiogram (ECG) data. The results indicated that IIRTV interacted with baseline RSA to influence trait impulsivity. These findings suggested that cognitive control indexed by IIRTV, might represent a central nervous correlate of trait impulsivity, and that it interacted with vagal tone indexed by baseline RSA, to influence trait impulsivity.

Limited evidence that alcohol affects emotional face processing via interoceptive pathways, a registered report

BACKGROUND

Our brain uses interoceptive signals from the body to shape how we perceive emotions in others; however, whether interoceptive signals can be manipulated to alter emotional perceptions is unknown. This registered report examined whether alcohol administration triggers physiological changes that alter interoceptive signals and manipulate emotional face processing.

METHODS

Participants (n=36) were administered an alcohol or placebo beverage. Cardiovascular physiology (Heartrate variability, HRD) was recorded before and after administration. Participants completed a behavioral task in which emotional faces were presented in synchrony with different phases of the cardiac cycle (i.e., systole/diastole) to index of how interoceptive signals amplify them.

HYPOTHESES

We hypothesized that alcohol administration would disrupt the cardiac amplification of emotional face processing. We further explored whether this disruption depended on the nature and magnitude of changes in cardiovascular physiology after alcohol administration.

RESULTS

We observed no main effects or interactions between alcohol administration and emotional face processing. We found that HRV at baseline negatively correlated with the cardiac amplification of emotional faces. The extent to which alcohol impacted HRV negatively correlated with the cardiac amplification of angry faces.

CONCLUSIONS

This registered report failed to validate the primary hypotheses but offers some evidence that the effects of alcohol on emotional face processing, if any, could be mediated via changes in basic physiological signals that are integrated via interoceptive mechanisms. Results are interpreted within the context of interoceptive inference and could feed novel perspectives for the interplay between physiological sensitivity and interoception in the development of drug-related behaviors.

Factor structure and psychometric properties of the Body Perception Questionnaire-Short Form (BPQ-SF); The Persian version

BACKGROUND

Body perception is considered an important physiological marker in physical and mental disorders, therefore, its valid and reliable quantification is indeed necessary. Due to the lack of a Persian version of an instrument with validated psychometric properties for evaluating body perception, this study aimed to investigate the factorial structure, reliability, and validity of body perception questionnaire-Short Form (BPQ-SF) among Iranian adults.

METHODS

A total of 748 participants (mean age = 31.74; 57%female) were included in the analysis. Participants were recruited using the online survey method. Confirmatory factor analysis (CFA) was performed and concurrent validity was determined by computing Pearson's correlation coefficient between BPQ_SF, Depression Anxiety Stress Scale (DASS), and somatization subscale of Symptom-Checklist-90 (SOM). Internal consistency (using Cronbach's alpha and McDonald's omega), and composite reliability were also evaluated.

RESULTS

The result of the CFA yielded three factors: Body Awareness, Subdiaphragmatic Reactivity, and Supradiaphragmatic Reactivity. Cronbach's alpha values for all BPQ_SF items were 0.94. Moreover, Concurrent validity between BPQ, SOM, and DASS was determined to be between 0.44 to 0.94. and had good internal consistency (McDonald's Omega range: .74-.93 Cronbach's alpha range: .76-.94).

CONCLUSIONS

The BPQ-SF demonstrated good psychometric properties among Iranians thus can be used to reliably assess body perception.

A longitudinal study on the relation between parenting and Toddler's disruptive behavior: what is the role of Toddler's negative emotionality and physiological stress reactivity?

Harsh and unsupportive parenting is a risk factor for the development of disruptive behavior in children. However, little is known about how children's temperament and stress reactivity influence this relation. In a three-wave longitudinal study, we examined whether the associations between parenting practices (supportive parenting, positive discipline, and harsh discipline) and child disruptive behavior were mediated by child temperament (negative emotionality) and stress reactivity (heart rate reactivity). In 72 families (Mage child = 14.6 months), living in the Netherlands, parents reported on their parenting practices and their children's disruptive behavior and negative emotionality. Children's heart rate reactivity was assessed through a series of stress-inducing tasks. Results from regression-based mediation analyses with bootstrapping showed that negative emotionality and stress reactivity did not mediate the relation between parenting and disruptive behavior. The results overall demonstrate that in a group of children this age, a reinforcing dynamic between parenting, child stress and disruptive behavior is not yet firmly established.

Brain mechanisms underlying the modulation of heart rate variability when accepting and reappraising emotions

Heart rate variability (HRV) has been linked to resilience and emotion regulation (ER). How HRV and brain processing interact during ER, however, has remained elusive. Sixty-two subjects completed the acquisition of resting HRV and task HRV while performing an ER functional Magnetic Resonance Imaging (fMRI) paradigm, which included the differential strategies of ER reappraisal and acceptance in the context of viewing aversive pictures. We found high correlations of resting and task HRV across all emotion regulation strategies. Furthermore, individuals with high levels of resting, but not task, HRV showed numerically lower distress during ER with acceptance. Whole-brain fMRI parametrical modulation analyses revealed that higher task HRV covaried with dorso-medial prefrontal activation for reappraisal, and dorso-medial prefrontal, anterior cingulate and temporo-parietal junction activation for acceptance. Subjects with high resting HRV, compared to subjects with low resting HRV, showed higher activation in the pre-supplementary motor area during ER using a region of interest approach. This study demonstrates that while resting and task HRV exhibit a positive correlation, resting HRV seems to be a better predictor of ER capacity. Resting and task HRV were associated with ER brain activation in mid-line frontal cortex (i.e. DMPFC).

From inner to dyadic connection: the role of mindfulness in mother-infant interaction during the first year of life

Introduction

Mother-infant attunement is fundamental to supporting infant socio-emotional development. Based on the assumption that we connect better with others if we are aware of and connected with our own experience, mindfulness could affect the maternal ability to attune to the infant. However, little is known about this topic in the first year of life. Study 1 aimed to investigate the role of maternal dispositional mindfulness and mindful parenting in mother-infant physiological and behavioral attunement at 3 months of age. Study 2 aimed to explore the effect of a mindfulness-based intervention not specific to parenting experience on mother-infant behavioral and physiological attunement and on maternal wellbeing at 9 months of age.

Methods

In Study 1, mother-infant (n = 67) behavioral and physiological attunement (i.e., co-regulation and RSA) were collected simultaneously each 20 s during face-to-face interaction. Mothers completed questionnaires about their dispositional mindfulness and mindful parenting. In Study 2, mother-infant dyads were randomly divided into a control (n = 20) and an intervention group (n = 29). The intervention group attended a 5-week mindfulness-based intervention. At T1 and T2, the same procedure described in Study 1 was applied and mothers reported about their wellbeing.

Results

Results showed that maternal mindfulness was associated with high physiological and behavioral attunement at 3 months and with more positive maternal behaviors and less stress at 9 months. Analysis evidenced a slight improvement in the intervention group in maternal dispositional mindfulness and a reduction in parenting stress at T2.

Discussion

Findings from both studies suggested that maternal mindfulness could represent a protective factor that could support mothers in fostering better dyadic interactions with their infants. The implementation of mindfulness-based interventions for mothers could have preventive and clinical implications.

Trustworthiness judgments and pupil-size in individuals with schizophrenia

Individuals with schizophrenia show aberrant processing of social cues. In the current study, we (1) compared trustworthiness ratings of faces between patients with schizophrenia and healthy controls, (2) compared pupillary reactivity between patients and controls (3) examined whether trustworthiness judgments in schizophrenia are related to pupil reactivity, (4) and examined associations between trustworthiness judgements and symptom severity, specifically paranoia. Patients with schizophrenia spectrum disorders (N = 48) and healthy controls (N = 33) completed a Trustworthiness Task, during which their pupil size was measured via an eye-tracking device. The mean baseline-corrected pupil size was calculated from 24 pictures of real neutral faces, each presented for 2500 ms. Self-reported psychotic experiences were measured by Community Assessment of Psychic Functioning (CAPE-42), and symptom severity was rated by Brief Psychiatric Rating Scale (BPRS). No group differences were found in trustworthiness ratings or pupil reactivity parameters during trustworthiness judgments. Separately, among patients, absolute difference in pupil-size change and dilation after reaching minimum size were related to more severe positive symptoms and self-reported paranoia. Our results did not show social cognitive biases in the stable outpatients with schizophrenia, or the role of pupil reactivity in trustworthiness judgments. Future studies should use longer stimuli for pupillary reactivity and control the type and dosage of utilized antipsychotic medication. Further studies are required to explore relationships in larger and more symptomatic groups of patients.

Elevated unanticipated acoustic startle reactivity in dyslexia

People with dyslexia, a neurodevelopmental disorder of reading, are highly attuned to the emotional world. Compared with their typically developing peers, children with dyslexia exhibit greater autonomic nervous system reactivity and facial behaviour to emotion- and empathy-inducing film clips. Affective symptoms, such as anxiety, are also more common in children with dyslexia than in those without. Here, we investigated whether the startle response, an automatic reaction that lies at the interface of emotion and reflex, is elevated in dyslexia. We measured facial behaviour, electrodermal reactivity (a sympathetic nervous system measure) and emotional experience in response to a 100 ms, 105 dB unanticipated acoustic startle task in 30 children with dyslexia and 20 comparison children without dyslexia (aged 7-13) who were matched on age, sex and nonverbal reasoning. Our results indicated that the children with dyslexia had greater total facial behaviour and electrodermal reactivity to the acoustic startle task than the children without dyslexia. Across the sample, greater electrodermal reactivity during the startle predicted greater parent-reported anxiety symptoms. These findings contribute to an emerging picture of heightened emotional reactivity in dyslexia and suggest accentuated sympathetic nervous system reactivity may contribute to the elevated anxiety that is often seen in this population.

Daily COVID-19 Stressor Effects on Children's Mental Health Depend on Pre-pandemic Peer Victimization and Resting Respiratory Sinus Arrhythmia

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.

Basal parasympathetic deficits in C9orf72 hexanucleotide repeat expansion carriers relate to smaller frontoinsula and thalamus volume and lower empathy

Diminished basal parasympathetic nervous system activity is a feature of frontotemporal dementia that relates to left frontoinsula dysfunction and empathy impairment. Individuals with a pathogenic expansion of the hexanucleotide repeat in chromosome 9 open reading frame 72 (C9orf72), the most common genetic cause of frontotemporal dementia and amyotrophic lateral sclerosis, provide a unique opportunity to examine whether parasympathetic activity is disrupted in genetic forms of frontotemporal dementia and to investigate when parasympathetic deficits manifest in the pathophysiological cascade. We measured baseline respiratory sinus arrhythmia, a parasympathetic measure of heart rate variability, over two minutes in a sample of 102 participants that included 19 asymptomatic expansion carriers (C9+ asymp), 14 expansion carriers with mild cognitive impairment (C9+ MCI), 16 symptomatic expansion carriers with frontotemporal dementia (C9+ FTD), and 53 expansion-negative healthy controls (C9- HC) who also underwent structural magnetic resonance imaging. In follow-up analyses, we compared baseline respiratory sinus arrhythmia in the C9+ FTD group with an independent age-, sex-, and clinical severity-matched group of 26 people with sporadic behavioral variant frontotemporal dementia. The Frontotemporal Lobar Degeneration-modified Clinical Dementia Rating-Sum of Boxes score was used to quantify behavioral symptom severity, and informant ratings on the Interpersonal Reactivity Index provided measures of participants' current emotional (empathic concern) and cognitive (perspective-taking) empathy. Results indicated that the C9+ FTD group had lower baseline respiratory sinus arrhythmia than the C9+ MCI, C9+ asymp, and C9- HC groups, a deficit that was comparable to that of sporadic behavioral variant frontotemporal dementia. Linear regression analyses indicated that lower baseline respiratory sinus arrhythmia was associated with worse behavioral symptom severity and lower empathic concern and perspective-taking across the C9orf72 expansion carrier clinical spectrum. Whole-brain voxel-based morphometry analyses in participants with C9orf72 pathogenic expansions found that lower baseline respiratory sinus arrhythmia correlated with smaller gray matter volume in the left frontoinsula and bilateral thalamus, key structures that support parasympathetic function, and in the bilateral parietal lobes, occipital lobes, and cerebellum, regions that are also vulnerable in individuals with C9orf72 expansions. This study provides novel evidence that basal parasympathetic functioning is diminished in FTD due to C9orf72 expansions and suggests that baseline respiratory sinus arrhythmia may be a potential non-invasive biomarker that is sensitive to behavioral symptoms in the early stages of disease.

Vagus Nerve and Gut-Brain Communication

The vagus nerve, as an important component of the gut-brain axis, plays a crucial role in the communication between the gut and brain. It influences food intake, fat metabolism, and emotion by regulating the gut-brain axis, which is closely associated with the development of gastrointestinal, psychiatric, and metabolism-related disorders. In recent years, significant progress has been made in understanding the vagus-mediated regulatory pathway, highlighting its profound implications in the development of many diseases. Here, we summarize the latest advancements in vagus-mediated gut-brain pathways and the novel interventions targeting the vagus nerve. This will provide valuable insights for future research on treatment of obesity and gastrointestinal and depressive disorders based on vagus nerve stimulation.

Clients' and therapists' parasympathetic interpersonal and intrapersonal regulation dynamics during psychotherapy for depression

OBJECTIVE

The 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.

METHOD

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.

RESULTS

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.

CONCLUSION

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.

New policies on skin-to-skin contact warrant an oxytocin-based perspective on perinatal health care

Background

In 2023, the World Health Organization (WHO) published a Global Position Paper on Kangaroo Mother Care (KMC), which is applicable to all countries worldwide: from the moment of birth, every "small and sick" newborn should remain with mother in immediate and continuous skin-to-skin contact (SSC), receiving all required clinical care in that place. This was prompted by the startling results of a randomized controlled trial published in 2021: in which 1,609 infants receiving immediate SSC were compared with 1,602 controls that were separated from their mothers but otherwise received identical conventional state-of-the-art care. The intervention infants showed a 25% reduction in mortality after 28 days.

New perspectives

The new WHO guidelines are a significant change from earlier guidance and common clinical practice. The author presents that separating mothers and babies is assumed to be "normal" (a paradigm) but actually puts newborns at increased risk for morbidity and mortality. The author presents arguments and ethical perspectives for a new perspective on what is "normal," keeping newborns with their mothers is the infant's physiological expectation and critical requirement for healthy development. The author reviews the scientific rationale for changing the paradigm, based on synchronous interactions of oxytocin on both mother and infant. This follows a critique of the new policies that highlights the role of immediate SSC.

Actionable recommendations

This critique strengthens the case for implementing the WHO guidelines on KMC for small and sick babies. System changes will be necessary in both obstetric and neonatal settings to ensure seamless perinatal care. Based on the role of oxytocin, the author identifies that many current routine care practices may actually contribute to stress and increased vulnerability to the newborn. WHO has actionable recommendations about family involvement and presence in newborn intensive care units.

Discussion

The concepts of resilience and vulnerability have specific definitions well known in perinatal care: the key outcome of care should be resilience rather than merely the absence of vulnerability. Newborns in all settings and contexts need us to re-evaluate our paradigms and adopt and implement the new WHO guidelines on KMC in perinatal care.

Survival, Attachment, and Healing: An Evolutionary Lens on Interventions for Trauma-Related Dissociation

Purpose

Dissociation is a necessary part of our threat response system, common to all animal species, normally temporarily activated under conditions of extreme or inescapable threat. Pathological dissociation, however, continues to occur after the initial threat has passed, in response to reminders or inaccessibility of safety and security. Present across the spectrum of psychiatric diagnoses, recurrent dissociative symptoms are linked to severe trauma exposure, insecure attachment, treatment non-response, and maladaptive coping behaviors such as substance use, suicidality, and self-harm. However, empirical studies testing treatments specific to dissociative processes remain scarce. This narrative review summarizes existing studies and provides theoretical, neurobiological, and evolutionary perspectives on dissociative processes and treatments for pathological dissociation.

Methods

A systematic search of five databases (MEDLINE, EMBASE, APA PsycINFO, CINAHL plus, Scopus) was conducted on April 13, 2023. Peer-reviewed clinical studies with adult participants, assessing intervention effects on dissociative symptoms, were included. Results were thematically analyzed and summarized.

Results

Sixty-nine studies were identified, mainly focused on posttraumatic stress disorder, trauma-exposed populations, and borderline personality disorder. Psychotherapy was studied in 72.5% of studies; other interventions included medications and neurostimulation. The majority reported positive outcomes, despite the heterogeneous spectrum of interventions. However, treatment of dissociative symptoms was the primary objective in only a minority.

Conclusion

Pathological dissociation is a complex phenomenon involving brain and body systems designed for perceiving and responding to severe threats, requiring an individualized approach. A literature is emerging regarding potentially evidence-based treatments to help those impacted by recurrent dissociative symptoms. When contextualized within a neurobiological and evolutionary perspective, these treatments can be understood as facilitating an internal and/or relational sense of safety, resulting in symptom reduction. Further studies are needed to explore effective treatments for dissociative symptoms.

A theoretical exploration of polyvagal theory in creative arts and psychomotor therapies for emotion regulation in stress and trauma

Polyvagal theory advocates for working with the body, becoming aware of the body and connecting with the senses. Similarly, paying attention to and influencing one's physical and sensory experience is a core aspect of the creative arts and psychomotor therapies. Polyvagal theory offers opportunities for strengthening resilience by treating emotion-regulation problems, stress, and trauma, as well as restoring regulation of the autonomic nervous system. Paying attention to and influencing physical and sensory experiences are core aspects of creative arts and psychomotor therapies. This theoretical paper explores how polyvagal theory can serve as a foundational theory and support the creative arts and psychomotor therapies for emotion regulation in stress and trauma. A number of pillars in polyvagal theory have links with arts therapies, such as an emphasis on physical and sensory experience in situations of safety or threat. This theory may offer insight into the role of the body in stressful situations, the role of co-and self-regulation, and thus the functioning of and the rationale for use of creative arts and psychomotor therapies. Through interventions focused on promoting healthy autonomic responses and regulating physiological responses, clients can learn to better regulate and process their emotional experiences. Although this could be broadly useful, it would seem particularly promising in therapies focused on stress and trauma. This article provides an introduction to polyvagal theory and outlines how it can serve as an explanatory, hypothetical model for the working mechanisms that underlie creative arts and psychomotor therapies. The application of PVT in creative arts and psychomotor therapies will be explored by describing techniques for "noticing and naming" and "learning to change," as well as by highlighting the role of PVT in the therapeutic relationship. It provides case examples and discusses the role of creative arts and psychomotor therapies for stress regulation and resilience conceptualized in line with the polyvagal theory.

Social Communication in Young Children With Sex Chromosome Trisomy (XXY, XXX, XYY): A Study With Eye Tracking and Heart Rate Measures

OBJECTIVE

Children with sex chromosome trisomy (SCT) have an increased risk for suboptimal development. Difficulties with language are frequently reported, start from a very young age, and encompass various domains. This cross-sectional study examined social orientation with eye tracking and physiological arousal responses to gain more knowledge on how children perceive and respond to communicative bids and evaluated the associations between social orientation and language outcomes, concurrently and 1 year later.

METHOD

In total, 107 children with SCT (33 XXX, 50 XXY, and 24 XYY) and 102 controls (58 girls and 44 boys) aged between 1 and 7 years were included. Assessments took place in the USA and Western Europe. A communicative bids eye tracking paradigm, physiological arousal measures, and receptive and expressive language outcomes were used.

RESULTS

Compared to controls, children with SCT showed reduced attention to the face and eyes of the on-screen interaction partner and reduced physiological arousal sensitivity in response to direct versus averted gaze. In addition, social orientation to the mouth was related to concurrent receptive and expressive language abilities in 1-year-old children with SCT.

CONCLUSIONS

Children with SCT may experience difficulties with social communication that extend past the well-recognized risk for early language delays. These difficulties may underlie social-behavioral problems that have been described in the SCT population and are an important target for early monitoring and support.

The Predictive Potential of Heart Rate Variability for Depression

Heart rate variability (HRV),a measure of the fluctuations in the intervals between consecutive heartbeats, is an indicator of changes in the autonomic nervous system. A chronic reduction in HRV has been repeatedly linked to clinical depression. However, the chronological and mechanistic aspects of this relationship, between the neural, physiological, and psychopathological levels, remain unclear. In this review we present evidence by which changes in HRV might precede the onset of depression. We describe several pathways that can facilitate this relationship. First, we examine a theoretical model of the impact of autonomic imbalance on HRV and its role in contributing to mood dysregulation and depression. We then highlight brain regions that are regulating both HRV and emotion, suggesting these neural regions, and the Insula in particular, as potential mediators of this relationship. We also present additional possible mediating mechanisms involving the immune system and inflammation processes. Lastly, we support this model by showing evidence that modification of HRV with biofeedback leads to an improvement in some symptoms of depression. The possibility that changes in HRV precede the onset of depression is critical to put to the test, not only because it could provide insights into the mechanisms of the illness but also because it may offer a predictive anddiagnosticphysiological marker for depression. Importantly, it could also help to develop new effective clinical interventions for treating depression.

Parent-child coregulation as a dynamic system: a commentary on Wass et al. (2024)

In this commentary, I argue that including and operationalizing allostatic processes will become increasingly important in future research on parent-child biobehavioral coregulation. In particular, the conceptualization and modeling of dyadic oscillatory rhythms that align in expected ways with the child's developmental stage and that distinguish typical and atypical development will be useful in future work. Despite the inherent asymmetry characteristic of parent-child relationships, we should not forget to consider the child's effects on the parent within and across time, the additional environmental demands upon parents that shape parent-child coregulation, and variations in parent-child asymmetry by parental risk factors. Studying risk factors that are dyadic in nature, such as child maltreatment, may be particularly informative in gaining a deeper understanding of how parent-child coregulation interfaces with developmental psychopathology. To best model parent-child coregulation as a dynamic system, it will be critical to employ more nonlinear analytic models and better represent the multiple hierarchical domains of coregulation and their interactions, including affect, cognition, behavior, and biology. Finally, in future research, a deeper application of existing dyadic and dynamic theories, as well as the generation of new dyadic developmental theories, will aid us in obtaining a stronger understanding of the developmental function and intervention implications of parent-child biobehavioral coregulation.

The Influence of Social Dynamics on Biological Aging and the Health of Historically Marginalized Populations: A Biopsychosocial Model for Health Disparities

Historically marginalized populations are susceptible to social isolation resulting from their unique social dynamics; thus, they incur a higher risk of developing chronic diseases across the course of life. Research has suggested that the cumulative effect of aging trajectories per se, across the lifespan, determines later-in-life disease risks. Emerging evidence has shown the biopsychosocial effects of social stress and social support on one's wellbeing in terms of inflammation. Built upon previous multidisciplinary findings, here, we provide an overarching model that explains how the social dynamics of marginalized populations shape their rate of biological aging through the inflammatory process. Under the framework of social stress and social support theories, this model aims to facilitate our understanding of the biopsychosocial impacts of social dynamics on the wellbeing of historically marginalized individuals, with a special emphasis on biological aging. We leverage this model to advance our mechanistic understanding of the health disparity observed in historically marginalized populations and inform future remediation strategies.

Oscillatory Coupling Between Neural and Cardiac Rhythms

Oscillations serve a critical role in organizing biological systems. In the brain, oscillatory coupling is a fundamental mechanism of communication. The possibility that neural oscillations interact directly with slower physiological rhythms (e.g., heart rate, respiration) is largely unexplored and may have important implications for psychological functioning. Oscillations in heart rate, an aspect of heart rate variability (HRV), show remarkably robust associations with psychological health. Mather and Thayer proposed coupling between high-frequency HRV (HF-HRV) and neural oscillations as a mechanism that partially accounts for such relationships. We tested this hypothesis by measuring phase-amplitude coupling between HF-HRV and neural oscillations in 37 healthy adults at rest. Robust coupling was detected in all frequency bands. Granger causality analyses indicated stronger heart-to-brain than brain-to-heart effects in all frequency bands except gamma. These findings suggest that cardiac rhythms play a causal role in modulating neural oscillations, which may have important implications for mental health.

Social interaction anxiety and sleep quality in youth: Individual difference in childhood adversity and cardiac vagal control

BACKGROUND

Social interaction anxiety and sleep problems are prevalent during adolescence. Social interaction anxiety undermines sleep quality, however, little is known whether the association between social interaction anxiety and sleep quality is moderated by environmental factors such as childhood adversity and individual factors such as cardiac vagal control. This study sought to investigate the moderating effects of childhood adversity and cardiac vagal control on the link between social interaction anxiety and sleep quality.

METHOD

The Social Interaction Anxiety Scale, the Pittsburgh Sleep Quality Index and the Childhood Trauma Questionnaire were administered to 274 adolescents, who received 3-min resting ECG recording to assess respiratory sinus arrhythmia (RSA) as an index of cardiac vagal control.

RESULTS

Social interaction anxiety was negatively associated with sleep quality, and this association was moderated by childhood adversity and cardiac vagal control. In specific, social interaction anxiety was negatively associated with sleep quality among adolescents with low childhood adversity regardless of cardiac vagal control. Sleep quality was generally disrupted when adolescents exposed to high childhood adversity, but the negative association between social interaction anxiety and sleep quality among adolescents with high childhood adversity could be amortized by high cardiac vagal control.

LIMITATIONS

Cross-sectional design precluded establishing causality among variables.

CONCLUSION

These findings suggest that high cardiac vagal control reflecting better self-regulation might buffer the negative effect of social interaction anxiety on sleep quality particularly among adolescents exposed to early life stress.

Integrated use of biofeedback and neurofeedback techniques in treating pathological conditions and improving performance: a narrative review

In recent years, the scientific community has begun tо explore the efficacy оf an integrated neurofeedback + biofeedback approach іn various conditions, both pathological and non-pathological. Although several studies have contributed valuable insights into its potential benefits, this review aims tо further investigate its effectiveness by synthesizing current findings and identifying areas for future research. Our goal іs tо provide a comprehensive overview that may highlight gaps іn the existing literature and propose directions for subsequent studies. The search for articles was conducted on the digital databases PubMed, Scopus, and Web of Science. Studies to have used the integrated neurofeedback + biofeedback approach published between 2014 and 2023 and reviews to have analyzed the efficacy of neurofeedback and biofeedback, separately, related to the same time interval and topics were selected. The search identified five studies compatible with the objectives of the review, related to several conditions: nicotine addiction, sports performance, Autism Spectrum Disorder (ASD), and Attention Deficit Hyperactivity Disorder (ADHD). The integrated neurofeedback + biofeedback approach has been shown to be effective in improving several aspects of these conditions, such as a reduction in the presence of psychiatric symptoms, anxiety, depression, and withdrawal symptoms and an increase in self-esteem in smokers; improvements in communication, imitation, social/cognitive awareness, and social behavior in ASD subjects; improvements in attention, alertness, and reaction time in sports champions; and improvements in attention and inhibitory control in ADHD subjects. Further research, characterized by greater methodological rigor, is therefore needed to determine the effectiveness of this method and the superiority, if any, of this type of training over the single administration of either. This review іs intended tо serve as a catalyst for future research, signaling promising directions for the advancement оf biofeedback and neurofeedback methodologies.

Autonomic nervous system responses to social stimuli among autistic individuals: A systematic review and meta-analysis

Physiological responses to environmental and social stimuli have been studied broadly in relation to psychological states and processes. This may be especially important regarding autistic individuals, who show disparities in social interactions. However, findings from studies assessing autonomic nervous system (ANS) responses of autistic individuals present contradictions, with reports showing both autonomic disparities and intact autonomic functioning. The current study aimed to review the existing literature and to estimate if there is a difference between autistic individuals and neurotypical (NT) individuals in their autonomic responses to social stimuli. Furthermore, the study examined factors that may moderate this difference, including the type of physiological function measured, the level of participation required, as well as the age and intellectual functioning of the participants. The meta-analysis revealed a small and statistically insignificant overall difference between autistic and NT individuals, albeit with high heterogeneity. A further nested moderator analysis revealed a significant difference between autistic and NT individuals in physiological response that reflects mainly a parasympathetic nervous system (PNS) activity. Another difference was found in physiological response that reflects a combined activity of the sympathetic and parasympathetic systems, but only for experimental tasks that demanded active participation in social interactions. These results suggest a distinctiveness in autonomic regulation of autistic individuals in social situations, and point to the PNS as an important study objective for future investigation.

Transcutaneous Auricular Vagus Nerve Stimulation to Improve Emotional State

Emotional experiences are a part of our lives. The maladaptive functioning of an individual's emotional field can lead to emotional disturbances of various kinds, such as anxiety and depression. Currently, there is an increasing prevalence of emotional disorders that cause great human suffering and high socioeconomic costs. Emotional processing has a biological basis. The major neuroscientific theories of emotion are based on biological functioning, and all of them take into account the anatomy and function of the tenth cranial nerve: the vagus nerve. The vagus nerve connects the subdiaphragmatic and supradiaphragmatic areas and modulates emotional processing as the basis of interoceptive functioning. Auricular vagus nerve stimulation is a new and innovative neuromodulation technique based on the function of the vagus nerve. Several interventions have shown that this new neurostimulation technique is a very promising resource for treating emotional disorders. In this paper, we summarise three neuroscientific theories of emotion, explain what transcutaneous auricular nerve stimulation is, and present arguments for its use and continued research.

Parasympathetic Nervous System Functioning Moderates the Associations between Callous-Unemotional Traits and Emotion Understanding Difficulties in Late Childhood

BACKGROUND

Callous-unemotional (CU) traits are characterized by low empathy, guilt, and prosociality, putting children at risk for lifespan antisocial behavior. Elevated CU traits have been linked separately to difficulties with emotion understanding (i.e., identifying emotional states of others) and disrupted parasympathetic nervous system (PNS) functioning. However, no study has investigated how PNS functioning and emotion understanding are jointly related to CU traits.

METHOD

We explored associations between CU traits, emotion understanding, and PNS functioning (indexed via respiratory sinus arrhythmia [RSA]) among children aged 7-10 years old (n = 55). We also tested whether deficits in emotion understanding differ across specific emotions (i.e., fear, pain, happiness, anger). Each child's RSA was continuously recorded while they watched a film that included emotionally evocative social interactions. To assess emotion understanding, children identified emotions replayed in 1s animations of scenes from the film. Parents reported on child CU traits, conduct problems, and demographic information.

RESULTS

Higher CU traits were related to lower emotion understanding (β = -0.43, p = 0.03). PNS activity during the film moderated this association (β = -0.47, p < 0.001), such that CU traits were associated with lower emotion understanding among children with mean (B = -0.01, t = -2.46, p = 0.02) or high (i.e., 1 SD > M; B = -0.02, t = -3.00, p < 0.001) RSA levels during the film, but not among children with low RSA levels (i.e., 1 SD < M; B = 0.00, t = -0.53, p = 0.60). Moreover, we found that the observed moderated associations are driven by deficits in fear, specifically.

CONCLUSIONS

The link between poorer emotion understanding, fear understanding in particular, and CU traits was attenuated for children who demonstrated patterns of PNS functioning consistent with attentional engagement while viewing the emotion stimuli.

Susceptibility to peer influence in adolescents: Associations between psychophysiology and behavior

The current study investigated in-the-moment links between adolescents' autonomic nervous system activity and susceptibility to three types of peer influence (indirect, direct, continuing) on two types of behavior (antisocial, prosocial). The sample included 144 racially ethnically diverse adolescents (46% male, 53% female, 1% other; M age  = 16.02 years). We assessed susceptibility to peer influence behaviorally using the Public Goods Game (PGG) while measuring adolescents' mean heart rate (MHR) and pre-ejection period (PEP). Three key findings emerged from bivariate dual latent change score modeling: (1) adolescents whose MHR increased more as they transitioned from playing the PGG alone (pre-influence) to playing while simply observed by peers (indirect influence) displayed more prosocial behavior; (2) adolescents whose PEP activity increased more (greater PEP activity = shorter PEP latency) as they transitioned from indirect influence to being encouraged by peers to engage in antisocial behavior (direct influence) engaged in more antisocial behavior; and (3) adolescents whose PEP activity decreased less as they transitioned from direct influence on prosocial behavior to playing the PGG alone again (continuing influence) displayed more continuing prosocial behavior (marginal effect). The discussion focuses on the role of psychophysiology in understanding adolescents' susceptibility to peer influence.

Calm Contact Technique Based on the Endocrinological Mechanism of Hypnosis-A Theoretical Proposal

This paper proposes the "calm contact" technique: an imaginative scenario where someone is in gentle contact with a loved one where the essence of the experience is to enjoy safety and calmness in peaceful social contact. The theoretical background is outlined by combining the brain mechanisms of stress reactions and hypnosis. In addition to the ancient stress responses (flight or fight or freeze), there are oxytocin-based options at the human level: tend and befriend behavior and the state of calm and connection, which is not a stress reaction but a resting reaction. These social-based reactions could prevent the organism from the primitive freezing response. Some studies proved that "hypnosis" as a setting reduces cortisol levels and could raise oxytocin levels. The beneficial mechanisms of the "calm contact" technique are analyzed in relation to "social support" and the psychoaffective effects of central oxytocin. The subjective effects of the proposed technique are outlined based on reports of healthy volunteers. The "calm contact" technique could be an alternative or adjunct to the "safe place" technique, applying the recent findings of endocrinological brain mechanisms of hypnosis. Clinical implications and limitations are briefly summarized.

Regional associations of white matter integrity and neurological, post-traumatic stress disorder and autonomic symptoms in Veterans with and without history of loss of consciousness in mild TBI

Background

Posttraumatic stress disorder (PTSD) and mild traumatic brain injury (mTBI) share overlapping symptom presentations and are highly comorbid conditions among Veteran populations. Despite elevated presentations of PTSD after mTBI, mechanisms linking the two are unclear, although both have been associated with alterations in white matter and disruptions in autonomic regulation. The present study aimed to determine if there is regional variability in white matter correlates of symptom severity and autonomic functioning in a mixed sample of Veterans with and without PTSD and/or mTBI (N = 77).

Methods

Diffusion-weighted images were processed to extract fractional anisotropy (FA) values for major white matter structures. The PTSD Checklist-Military version (PCL-M) and Neurobehavioral Symptom Inventory (NSI) were used to determine symptom domains within PTSD and mTBI. Autonomic function was assessed using continuous blood pressure and respiratory sinus arrythmia during a static, standing angle positional test. Mixed-effect models were used to assess the regional specificity of associations between symptom severity and white matter, with FA, global symptom severity (score), and white matter tract (tract) as predictors. Additional interaction terms of symptom domain (i.e., NSI and PCL-M subscales) and loss of consciousness (LoC) were added to evaluate potential moderating effects. A parallel analysis was conducted to explore concordance with autonomic functioning.

Results

Results from the two-way Score × Tract interaction suggested that global symptom severity was associated with FA in the cingulum angular bundle (positive) and uncinate fasciculus (negative) only, without variability by symptom domain. We also found regional specificity in the relationship between FA and autonomic function, such that FA was positively associated with autonomic function in all tracts except the cingulum angular bundle. History of LoC moderated the association for both global symptom severity and autonomic function.

Conclusions

Our findings are consistent with previous literature suggesting that there is significant overlap in the symptom presentation in TBI and PTSD, and white matter variability associated with LoC in mTBI may be associated with increased PTSD-spectra symptoms. Further research on treatment response in patients with both mTBI history and PTSD incorporating imaging and autonomic assessment may be valuable in understanding the role of brain injury in treatment outcomes and inform treatment design.

Practice effects of a breathing technique on pilots' cognitive and stress associated heart rate variability during flight operations

Commercial pilots endure multiple stressors in their daily and occupational lives which are detrimental to psychological well-being and cognitive functioning. The Quick coherence technique (QCT) is an effective intervention tool to improve stress resilience and psychophysiological balance based on a five-minute paced breathing exercise with heart rate variability (HRV) biofeedback. The current research reports on the application of QCT training within an international airline to improve commercial pilots' psychological health and support cognitive functions. Forty-four commercial pilots volunteered in a one-month training programme to practise self-regulated QCT in day-to-day life and flight operations. Pilots' stress index, HRV time-domain and frequency-domain parameters were collected to examine the influence of QCT practice on the stress resilience process. The results demonstrated that the QCT improved psychophysiological indicators associated with stress resilience and cognitive functions, in both day-to-day life and flight operation settings. HRV fluctuations, as measured through changes in RMSSD and LF/HF, revealed that the resilience processes were primarily controlled by the sympathetic nervous system activities that are important in promoting pilots' energy mobilization and cognitive functions, thus QCT has huge potential in facilitating flight performance and aviation safety. These findings provide scientific evidence for implementing QCT as an effective mental support programme and controlled rest strategy to improve pilots' psychological health, stress management, and operational performance.

Adrenocortical and autonomic cross-system regulation in youth: A meta-analysis

Childhood and adolescence are salient periods for the development of adrenocortical and autonomic arms of the stress response system (SRS), setting the stage for subsequent health and adaptive functioning. Although adrenocortical and autonomic systems theoretically function in highly coordinated ways, the strength of the relationship between these systems remains unclear. We leveraged a multivariate mixed effects meta-analytic approach to assess associations between adrenocortical, sympathetic, and parasympathetic functioning at rest and reactivity during stress-inducing tasks across 52 studies (N = 7,671; 5-20 years old). Results suggested a modest positive relation between adrenocortical and sympathetic systems as well as between adrenocortical and parasympathetic systems. Moderation analyses indicated the strength of associations varied as a function of several methodological and sociodemographic characteristics. Environmental effects on cross-system regulation were less clear, perhaps due to underrepresentation of adverse-exposed youth in the included studies. Collectively, our findings call for greater methodological attention to the dynamical, non-linear nature of cross-system functioning, as well as the role of experience in their organization across development.

Acute stress reduces attentional blindness: Relations with resting respiratory sinus arrhythmia and cortisol

This study made the first attempt to combine resting respiratory sinus arrhythmia (RSA) and cortisol to provide an explanatory mechanism for the effect of acute stress on emotion-induced blindness (EIB) from the perspective of vagus nerve activity and stress hormone responses. For this purpose, resting electrocardiogram (ECG) signals were recorded first. Participants underwent both the socially evaluated cold-pressor test and control treatments 7 days apart and then completed the EIB task. Heart rate and saliva samples were collected over time. The results demonstrated that acute stress promoted the overall detection of targets. Resting RSA and cortisol levels predicted the stress-induced changes in EIB performance under the negative distractor condition at lag2 negatively and positively, respectively. These findings indicate that the effect of stress on EIB was partially contributed by cortisol, which is more relevant to negative distractor conditions. Resting RSA, as an indicator of inter-individual differences, further provided evidence from the perspective of the trait emotional regulation ability based on the vagus nerve control. In general, resting RSA and cortisol changes over time exhibit different patterns of influence on stress-induced changes in EIB performance. Thus, this study provides a more comprehensive understanding of the effect of acute stress on attentional blindness.

The long-term impact of early adverse experience on adaptive functioning: a pilot study integrating measures of mental status, nonverbal communication, and heart rate variability

Background: Childhood maltreatment (CM) can disrupt the development of behavioural and physiological systems, increasing the risk of physical and psychological adverse outcomes across the lifespan. CM may cause interpersonal dysfunctions that impair social communication and lead to dysfunctional activation of the autonomic nervous system. The present exploratory study analyzed the long-term impact of CM from an integrated perspective through the simultaneous assessment of psychological symptoms, social and behavioural communication, and physiological regulation.

Methods: Participants were 55 healthy university students (9 males and 46 females; mean age ± SD = 25.26 ± 2.83 years), who filled out a battery of questionnaires to assess the presence of CM (Childhood Trauma Questionnaire) and psychopathological symptoms (Symptom Check-List-90 Item Revised). Participants were then subjected to a videotaped interview for the assessment of non-verbal behaviour (Ethological Coding System for Interviews) and measurement of tonic heart rate variability (HRV), a measure of physiological adaptability to the environment. We performed Pearson's correlation analysis to evaluate the associations between non-verbal behaviour, HRV, and CM variables. Multiple regression analysis was used to evaluate the independent associations between CM variables on HRV and nonverbal behaviour.

Results: We found an association between more severe CM, increased symptoms-related distress (ps < .001), less submissive behaviour (ps < .018), and decreased tonic HRV (ps < .028). As a result of multiple regression analysis, participants with a history of emotional abuse (R² = .18, p = .002) and neglect (R² = .10, p = .03) were more likely to display decreased submissive behaviour during the dyadic interview. Moreover, early experience of emotional (R² = .21, p = .005) and sexual abuse (R² = .14, p = .04) was associated with decreased tonic HRV.

Conclusion: Our preliminary findings show the utility of analyzing the long-term effects of adverse early experiences at different levels of ‘adaptive functioning’ (the capabilities needed to respond effectively to environmental demands).

Substantial traumatic experiences during childhood, such as emotional abuse, emotional neglect, and sexual abuse were associated with lower heart rate variability levels in a sample of young adults.

Young adults with a history of emotional abuse and neglect were more likely to display decreased submissive behaviour (ethological behaviour) during the dyadic interview.

Severe childhood maltreatment was associated with increased symptoms-related distress, less submissive behaviour (ethological behaviour), and decreased tonic heart rate variability in young adults.

Equine-assisted interventions for veterans with posttraumatic stress disorder: a systematic review

Equine-assisted intervention therapy has a nearly 60-year history and has been shown to have a significant positive impact on various types of psychotherapy patients. Due to an increase in research on EAT, the number of existing methods of equine-assisted intervention therapy has gradually increased. Based on existing literature on the application of equine-assisted intervention therapy on veterans with post-traumatic stress disorder (PTSD), this study examines the characteristics of several types of equine interventions and includes a systematic review of peer-reviewed literature on equine-assisted interventions for veterans with PTSD published over the past 5 years, from 2018 to the present. Ten articles met the review criteria and served as the primary data for analysis. Several types of equine-assisted interventions were shown to have a beneficial psychological impact on veterans. However, some limitations were also found in the studies, such as that the majority of experiments were constrained by small sample sizes. Equine-assisted intervention therapy has been shown to be effective, but further research is merited, in order to focus on the specific details and theories involved in equine-assisted interventions, and on the welfare of the horses involved in the therapy.

Predicting postpartum depressive symptoms by evaluating self-report autonomic nervous system reactivity during pregnancy

OBJECTIVE

Altered self-reported autonomic reactivity is associated with worse mental health in the general population. Although dysfunctional changes in ANS during pregnancy have been investigated in relation to depressive symptoms, no studies addressed the relationship between self-report autonomic reactivity during pregnancy and depressive symptoms after the delivery. The present study aimed to assess the impact of prepartum self-reported autonomic reactivity on the development of postpartum depressive symptoms.

METHODS

In this longitudinal study, 170 women were assessed during pregnancy (i.e., second or third trimester) and after childbirth (i.e., one month after the delivery). Self-reported autonomic reactivity was assessed through the Body Perception Questionnaire - Short Form that evaluates the autonomic functions related to organs above (i.e., supradiaphragmatic reactivity) and below (i.e., subdiaphragmatic reactivity) the diaphragm. In addition, prepartum and postpartum depressive symptoms were evaluated using the Patient Health Questionnaire - 9.

RESULTS

Findings showed that higher prepartum supradiaphragmatic reactivity predicted higher depressive symptoms in the postpartum period (β = 0.112, p = 0.009) after controlling for prepartum depressive symptomatology and other potential covariates.

CONCLUSIONS

Evaluation of self-reported autonomic activity may be a useful tool to identify antenatally women at risk of postpartum depressive symptoms. Future studies are needed to evaluate the effectiveness of interventions aimed at reducing the threat-responsive autonomic reactivity at rest and improving adaptive autonomic regulation to prevent postpartum depression.

The vagal paradox: A polyvagal solution

Although there is a consistent literature documenting that vagal cardioinhibitory pathways support homeostatic functions, another less frequently cited literature implicates vagal cardioinhibitory pathways in compromises to survival in humans and other mammals. The latter is usually associated with threat reactions, chronic stress, and potentially lethal clinical conditions such as hypoxia. Solving this 'vagal paradox' in studies conducted in the neonatal intensive care unit served as the motivator for the Polyvagal Theory (PVT). The paradox is resolved when the different functions of vagal cardioinhibitory fibers originating in two anatomically distinguishable brainstem areas are recognized. One pathway originates in a dorsal area known as the dorsal motor nucleus of the vagus and the other in a ventral area of the brainstem known as nucleus ambiguus. Unlike mammals, in all ancestral vertebrates from which mammals evolved, cardioinhibitory vagal fibers primarily originate in the dorsal motor nucleus of the vagus. Thus, in mammals the vagus nerve is 'poly' vagal because it contains two distinct efferent pathways. Developmental and evolutionary biology identify a ventral migration of vagal cardioinhibitory fibers that culminate in an integrated circuit that has been labeled the ventral vagal complex. This complex consists of the interneuronal communication of the ventral vagus with the source nuclei involved in regulating the striated muscles of the head and face via special visceral efferent pathways. This integrated system enables the coordination of vagal regulation of the heart with sucking, swallowing, breathing, and vocalizing and forms the basis of a social engagement system that allows sociality to be a potent neuromodulator resulting in calm states that promote homeostatic function. These biobehavioral features, dependent on the maturation of the ventral vagal complex, can be compromised in preterm infants. Developmental biology informs us that in the immature mammal (e.g., fetus, preterm infant) the ventral vagus is not fully functional and myelinization is not complete; this neuroanatomical profile may potentiate the impact of vagal cardioinhibitory pathways originating in the dorsal motor nucleus of the vagus. This vulnerability is confirmed clinically in the life-threatening reactions of apnea and bradycardia in human preterm newborns, which are hypothetically mediated through chronotropic dorsal vagal pathways. Neuroanatomical research documents that the distribution of cardioinhibitory neurons representing these two distinct vagal source nuclei varies among mammals and changes during early development. By explaining the solution of the 'vagal paradox' in the preterm human, the paper highlights the functional cardioinhibitory functions of the two vagal source nuclei and provides the scientific foundation for the testing of hypotheses generated by PVT.