Individual differences in fear-potentiated startle as a function of resting heart rate variability: Implications for panic disorder

Predicting response to stepped-care cognitive behavioral therapy for insomnia using pre-treatment heart rate variability in cancer patients

OBJECTIVE

This study examined whether high frequency heart-rate variability (HF-HRV) and HF-HRV reactivity to worry moderate response to cognitive behavioural therapy for insomnia (CBT-I) within both a standard and stepped-care framework among cancer patients with comorbid insomnia. Biomarkers such as HF-HRV may predict response to CBT-I, a finding which could potentially inform patient allocation to different treatment intensities within a stepped-care framework.

METHODS

177 participants (86.3 % female; Mage = 55.3, SD = 10.4) were randomized to receive either stepped-care or standard CBT-I. 145 participants had their HRV assessed at pre-treatment during a rest and worry period. Insomnia symptoms were assessed using the Insomnia Severity Index (ISI) and daily sleep diary across five timepoints from pre-treatment to a 12-month post-treatment follow-up.

RESULTS

Resting HF-HRV was significantly associated with pre-treatment sleep efficiency and sleep onset latency but not ISI score. However, resting HF-HRV did not predict overall changes in insomnia across treatment and follow-up. Similarly, resting HF-HRV did not differentially predict changes in sleep diary parameters across standard or stepped-care groups. HRV reactivity was not related to any of the assessed outcome measures in both cross-sectional and longitudinal analyses.

CONCLUSION

Although resting HF-HRV was related to initial daily sleep parameters, HF-HRV measures did not significantly predict longitudinal responses to CBT-I. These findings suggest that HF-HRV does not predict treatment responsiveness to CBT-I interventions of different intensity in cancer patients.

Heart rate and heart rate variability in obsessive-compulsive disorder: Evidence from patients and unaffected first-degree relatives

Altered heart rate (HR) and heart rate variability (HRV) are common observations in psychiatric disorders. Yet, few studies have examined these cardiac measures in obsessive-compulsive disorder (OCD). The current study aimed to investigate HR and HRV, indexed by the root mean square of successive differences (RMSSD) and further time domain indices, as putative biological characteristics of OCD. Electrocardiogram was recorded during a five-minute resting state. Group differences between patients with OCD (n = 96), healthy participants (n = 112), and unaffected first-degree relatives of patients with OCD (n = 47) were analyzed. As potential moderators of group differences, we examined the influence of age and medication, respectively. As results indicated, patients with OCD showed higher HR and lower HRV compared to healthy participants. These group differences were not moderated by age. Importantly, subgroup analyses showed that only medicated patients displayed lower HRV compared to healthy individuals, while HR alterations were evident in unmedicated patients. Regarding unaffected first-degree relatives, group differences in HRV remained at trend level. Further, an age-moderated group differentiation showed that higher HRV distinguished relatives from healthy individuals in young adulthood, whereas at higher age lower HRV was indicative of relatives. Both the role of familial risk and medication in HRV alterations need further elucidation. Pending future studies, alterations in HR and potentially HRV might serve as useful indices to characterize the pathophysiology of OCD.

Heart rate variability: Evaluating a potential biomarker of anxiety disorders

Establishing quantifiable biological markers associated with anxiety will increase the objectivity of phenotyping and enhance genetic research of anxiety disorders. Heart rate variability (HRV) is a physiological measure reflecting the dynamic relationship between the sympathetic and parasympathetic nervous systems, and is a promising target for further investigation. This review summarizes evidence evaluating HRV as a potential physiological biomarker of anxiety disorders by highlighting literature related to anxiety and HRV combined with investigations of endophenotypes, neuroimaging, treatment response, and genetics. Deficient HRV shows promise as an endophenotype of pathological anxiety and may serve as a noninvasive index of prefrontal cortical control over the amygdala, and potentially aid with treatment outcome prediction. We propose that the genetics of HRV can be used to enhance the understanding of the genetics of pathological anxiety for etiological investigations and treatment prediction. Given the anxiety-HRV link, strategies are offered to advance genetic analytical approaches, including the use of polygenic methods, wearable devices, and pharmacogenetic study designs. Overall, HRV shows promising support as a physiological biomarker of pathological anxiety, potentially in a transdiagnostic manner, with the heart-brain entwinement providing a novel approach to advance anxiety treatment development.

Evaluating heart rate variability with 10 second multichannel electrocardiograms in a large population-based sample

Introduction

Heart rate variability (HRV), defined as the variability of consecutive heart beats, is an important biomarker for dysregulations of the autonomic nervous system (ANS) and is associated with the development, course, and outcome of a variety of mental and physical health problems. While guidelines recommend using 5 min electrocardiograms (ECG), recent studies showed that 10 s might be sufficient for deriving vagal-mediated HRV. However, the validity and applicability of this approach for risk prediction in epidemiological studies is currently unclear to be used.

Methods

This study evaluates vagal-mediated HRV with ultra-short HRV (usHRV) based on 10 s multichannel ECG recordings of N = 4,245 and N = 2,392 participants of the Study of Health in Pomerania (SHIP) from two waves of the SHIP-TREND cohort, additionally divided into a healthy and health-impaired subgroup. Association of usHRV with HRV derived from long-term ECG recordings (polysomnography: 5 min before falling asleep [N = 1,041]; orthostatic testing: 5 min of rest before probing an orthostatic reaction [N = 1,676]) and their validity with respect to demographic variables and depressive symptoms were investigated.

Results

High correlations (r = .52-.75) were revealed between usHRV and HRV. While controlling for covariates, usHRV was the strongest predictor for HRV. Furthermore, the associations of usHRV and HRV with age, sex, obesity, and depressive symptoms were similar.

Conclusion

This study provides evidence that usHRV derived from 10 s ECG might function as a proxy of vagal-mediated HRV with similar characteristics. This allows the investigation of ANS dysregulation with ECGs that are routinely performed in epidemiological studies to identify protective and risk factors for various mental and physical health problems.

Does anxiety explain why math-anxious people underperform in math?

Math-anxious people consistently underperform in math. The most widely accepted explanation for why this underperformance occurs is that math-anxious people experience heightened anxiety when faced with math, and this in-the-moment anxiety interferes with performance. Surprisingly, this explanation has not been tested directly. Here, using both self-report and physiological indices of anxiety, we directly test how much in-the-moment anxiety explains math-anxious underperformance. Results indicate that in-the-moment anxiety indeed explains why math-anxious people underperform-but only partially, suggesting a need to seriously consider alternative mechanisms. Results also showed that while some highly math-anxious individuals-those with high levels of heart rate variability-experienced less in-the-moment anxiety, they nevertheless performed no better at math. For these individuals, math-anxious underperformance must occur for reasons unrelated to in-the-moment anxiety. More broadly, our findings point to substantial individual heterogeneity in the mechanisms underlying math-anxious underperformance. Accounting for this mechanistic heterogeneity may prove vital for optimally boosting math performance in math-anxious individuals.

Child Emotion Regulation Capacity Moderates the Association Between Parent Behaviors and Child Distress During Pediatric Venipuncture

OBJECTIVES

Medical needle procedures are a common source of pain, distress, and fear for children, which can worsen over time and lead to needle noncompliance and avoidance, if unaddressed. Children's pain experience is multiply determined by external (e.g., parent behaviors) and internal (e.g., cognitive and affective) factors. Some parent behaviors (e.g., reassurance, giving control to child, empathy, apologies, criticism) have related to poor child pain experiences. No research has examined how children's internal emotion regulation, commonly measured via heart rate variability (HRV), may buffer, or strengthen this association. This study is the first to examine child HRV in relation to pain experiences, and as a moderator between a constellation of parent behaviors (reassurance, giving control, empathy) and child pain, fear, and distress.

METHODS

Sixty-one children aged 7-12 years undergoing venipuncture and a parent participated. Child HRV was measured before the procedure. After venipuncture, children rated their pain and fear. Parent and child behaviors during venipuncture were coded using the "distress promoting" and "distress" composites of the Child-Adult Medical Procedure Interaction Scale-Revised.

RESULTS

Children with lower HRV displayed greater distress. Child HRV moderated the positive association between parent behaviors (reassurance, giving control, empathy) and child distress such that the association was strongest among children with low HRV.

CONCLUSIONS

Findings suggest children with lower HRV, indicative of lower emotion regulation capacity, may be at risk of experiencing higher levels of distress and may be more vulnerable to distress when facing parent reassurance, giving control, and empathy verbalizations during venipuncture.

Characterizing change in vagal tone during the first three years of life: A systematic review and empirical examination across two longitudinal samples

Functioning of the parasympathetic nervous system (PNS), most often indexed by respiratory sinus arrhythmia (RSA), influences the volitional, cognitively-mediated forms of self-regulation across development. However, despite its clear relevance to children's self-regulation, and its utility as a transdiagnostic biomarker of emotion dysregulation and psychopathology, the ontogeny of vagal tone under conditions of homeostasis across infancy and early childhood is not well understood. The current research is comprised of two complementary studies. The first aims to address this gap by conducting a systematic review of the literature which has assessed resting RSA in the first three years of life. The second study uses data from two diverse, longitudinal datasets (n = 203 and n = 370) to model change in RSA from infancy to toddlerhood. Results from a systematic review of 62 studies meeting inclusion criteria suggest that measures of resting RSA increase over time and demonstrate moderate stability across infancy, toddlerhood, and preschool ages. Results from a series of models fit to longitudinal data in study two suggest that baseline RSA is characterized by stable increases across infancy and early childhood. Moreover, although there was equivocal evidence for individual variability in trajectories of RSA, the findings suggest that the individual differences in resting RSA may become entrenched in early life based on observed significant variance in growth model intercepts. In all, the current study contributes to our understanding of the developmental trajectories of baseline RSA across infancy and early childhood and should support future research examining links between children's parasympathetic regulation and their adjustment in early life.

Is Low Heart Rate Variability Associated with Emotional Dysregulation, Psychopathological Dimensions, and Prefrontal Dysfunctions? An Integrative View

Several studies have suggested a correlation between heart rate variability (HRV), emotion regulation (ER), psychopathological conditions, and cognitive functions in the past two decades. Specifically, recent data seem to support the hypothesis that low-frequency heart rate variability (LF-HRV), an index of sympathetic cardiac control, correlates with worse executive performances, worse ER, and specific psychopathological dimensions. The present work aims to review the previous findings on these topics and integrate them from two main cornerstones of this perspective: Porges' Polyvagal Theory and Thayer and Lane's Neurovisceral Integration Model, which are necessary to understand these associations better. For this reason, based on these two approaches, we point out that low HRV is associated with emotional dysregulation, worse cognitive performance, and transversal psychopathological conditions. We report studies that underline the importance of considering the heart-brain relation in order to shed light on the necessity to implement psychophysiology into a broader perspective on emotions, mental health, and good cognitive functioning. This integration is beneficial not only as a theoretical ground from which to start for further research studies but as a starting point for new theoretical perspectives useful in clinical practice.

In exogenous attention, time is the clue: Brain and heart interactions to survive threatening stimuli

The capture of exogenous attention by negative stimuli has been interpreted as adaptive for survival in a diverse and changing environment. In the present paper, we investigate the neural responses towards two discrete negative emotions with different biological meanings, disgust and fear, and its potential relationships with heart rate variability (HRV) as an index of emotional regulation. With that aim, 30 participants performed a digit categorization task while fear, disgust and neutral distractor pictures were presented. Resting HRV at baseline, behavioral responses, and event-related potentials were recorded. Whereas P1 amplitudes were highest to fear distractors, the disgust stimulation led to augmented P2 amplitudes compared to the rest of distractors. Interestingly, increased N2 amplitudes were also found to disgust distractors, but only in high HRV participants. Neural source estimation data point to the involvement of the insula in this exogenous attentional response to disgust. Additionally, disgust distractors provoked longer reaction times than fear and neutral distractors in the high HRV group. Present findings are interpreted in evolutionary terms suggesting that exogenous attention is captured by negative stimuli following a different time course for fear and disgust. Possible HRV influences on neural mechanisms underlying exogenous attention are discussed considering the potential important role of this variable in emotional regulation processes.

Resilience of the Hellenic navy seals assessed by heart rate variability during cognitive tasks

OBJECTIVES

The interaction between high physical performance under extreme conditions in military and the simultaneous control of the cognitive executive functioning has been a subject of research in literature for the past few decades. Stroop test and Heart-rate variability (HRV), have been verified valuable clinical tools for the assessment of cerebral and autonomic/ cardiovascular stress responses respectively.

METHODS

Thirty-four subjects were enrolled in this study. Of them, 18 were candidates under intense preparation for their enlistment in the Hellenic Navy SEALs (HN-SEALs) and 16 were healthy controls (HC). All subjects underwent stroop tasks, along with mental state and personality examination. HRV variables in time and frequency domains recordings were acquired, during each aforementioned cognitive testing procedure.

RESULTS

Our results showed that HNS's performance on both cognitive and emotion stroop tasks were equivalent to controls (p≥.054); however, HNS exhibited statistically significant lower levels of HRV in different time and frequency domain variables, compared to HC (ranged from p<.01 to p<.05). Finally, in a between group comparison of the psychometric tools, HNS had significantly higher somatization, anxiety and neuroticism than HC.

CONCLUSION

In conclusion, these findings indicate that HNS display flexibility in their autonomic regulation during cognitive and emotional tasks. This characteristic is closely related to problem solving or adaptability skills. Therefore, we support that HRV measurement turns out to be an invaluable tool for both scientific and clinical insights, promising to be an index regarding the psychophysiological resilience especially in the neurovisceral integration (NVI) model.

Key dimensions of post-traumatic stress disorder and endothelial dysfunction: a protocol for a mechanism-focused cohort study

INTRODUCTION

Both trauma exposure and post-traumatic stress disorder (PTSD) are associated with increased risk of cardiovascular disease (CVD), the leading cause of death in the USA. Endothelial dysfunction, a modifiable, early marker of CVD risk, may represent a physiological mechanism underlying this association. This mechanism-focused cohort study aims to investigate the relationship between PTSD (both in terms of diagnosis and underlying symptom dimensions) and endothelial dysfunction in a diverse, community-based sample of adult men and women.

METHODS AND ANALYSIS

Using a cohort design, 160 trauma-exposed participants without a history of CVD are designated to the PTSD group (n=80) or trauma-exposed matched control group (n=80) after a baseline diagnostic interview assessment. Participants in the PTSD group have a current (past month) diagnosis of PTSD, whereas those in the control group have a history of trauma but no current or past psychiatric diagnoses. Endothelial dysfunction is assessed via flow-mediated vasodilation of the brachial artery and circulating levels of endothelial cell-derived microparticles. Two higher order symptom dimensions of PTSD-fear and dysphoria-are measured objectively with a fear conditioning paradigm and attention allocation task, respectively. Autonomic imbalance, inflammation, and oxidative stress are additionally assessed and will be examined as potential pathway variables linking PTSD and its dimensions with endothelial dysfunction. Participants are invited to return for a 2-year follow-up visit to reassess PTSD and its dimensions and endothelial dysfunction in order to investigate longitudinal associations.

ETHICS AND DISSEMINATION

This study is conducted in compliance with the Helsinki Declaration and University of California, Los Angeles Institutional Review Board. The results of this study will be disseminated via articles in peer-reviewed journals and presentations at academic conferences and to community partners.

TRIAL REGISTRATION NUMBER

NCT03778307; pre-results.

Resting heart rate variability modulates the effects of concurrent working memory load on affective startle modification

Vagally mediated heart rate variability (vmHRV) is thought to index top-down control processes in emotion regulation. According to the Generalized Unsafety Theory of Stress (GUTS), resting vmHRV indexes top-down resources that are needed to inhibit subcortical threat circuits, which is important for context-appropriate affective responding. Although this notion has been supported by studies of affective startle (SR) modification, direct evidence that top-down resources are the linking mechanism between vmHRV and context-appropriate affective responding has been lacking. To investigate this possible mechanism, college-aged participants (n = 92) were recruited to complete a picture viewing task and a concurrent working memory (WM) task. Concurrent WM load was manipulated, and the auditory SR stimulus was delivered while viewing affective pictures. Electrocardiography and electromyography were recorded to assess vmHRV and SR eyeblink, respectively. Results showed that WM load attenuated affective SR modification. As expected, the attenuating effects of load on affective SR modification were stronger among low vmHRV relative to high vmHRV individuals, indicating that vmHRV is linked to context-appropriate affective responding through the mechanism of top-down resources. These results support the GUTS and suggest that atypical affective responding among low vmHRV individuals is attributed to the lack of WM resources. Our findings highlight the relation between vmHRV and top-down resources that have been implicated in emotion regulation and contribute to a better understanding of emotion dysregulation in psychopathology.

Impact of Water Temperature on Heart Rate Variability during Bathing

Background: Heart rate variability (HRV) is affected by many factors. This paper aims to explore the impact of water temperature (WT) on HRV during bathing. Methods: The bathtub WT was preset at three conditions: i.e., low WT (36–38 °C), medium WT (38–40 °C), and high WT (40–42 °C), respectively. Ten subjects participated in the data collection. Each subject collected five electrocardiogram (ECG) recordings at each preset bathtub WT condition. Each recording was 18 min long with a sampling rate of 200 Hz. In total, 150 ECG recordings and 150 WT recordings were collected. Twenty HRV features were calculated using 1-min ECG segments each time. The k-means clustering analysis method was used to analyze the rough trends based on the preset WT. Analyses of the significant differences were performed using the multivariate analysis of variance of t-tests, and the mean and standard deviation (SD) of each HRV feature based on the WT were calculated. Results: The statistics show that with increasing WT, 11 HRV features are significantly (p < 0.05) and monotonously reduced, four HRV features are significantly (p < 0.05) and monotonously rising, two HRV features are rising first and then reduced, two HRV features (fuzzy and approximate entropy) are almost unchanged, and vLF power is rising. Conclusion: The WT has an important impact on HRV during bathing. The findings in the present work reveal an important physiological factor that affects the dynamic changes of HRV and contribute to better quantitative analyses of HRV in future research works.

Covariate effects of resting heart rate variability on affective ratings and startle reflex during cognitive reappraisal of negative emotions

Heart Rate Variability (HRV) has been widely studied in laboratory settings due to its clinical implications, primarily as a potential biomarker of emotion regulation (ER). Studies have reported that individuals with higher resting HRV show more distinct startle reflexes to negative stimuli as compared to those with lower HRV. These responses have been associated with better defense system function when managing the context demands. There is, however, a lack of empirical evidence on the association between resting HRV and eyeblinks during laboratory tasks using instructed ER. This study explored the influence of tonic HRV on voluntary cognitive reappraisal through subjective and startle responses measured during an independent ER task. In total, 122 healthy participants completed a task consisting of attempts to upregulate, downregulate, or react naturally to emotions prompted by unpleasant pictures. Tonic HRV was measured for 5 minutes before the experiment began. Current results did not support the idea that self-reported and eyeblink responses were influenced by resting HRV. These findings suggest that, irrespective of resting HRV, individuals may benefit from strategies such as reappraisal that are useful for managing negative emotions. Experimental studies should further explore the role of individual differences when using ER strategies during laboratory tasks.

Heart rate variability moderates the between- and within-person associations between daily stress and negative affect

Stress exposure increases risk for depressive symptoms. However, there are substantial individual differences in affective responses to stress. High-frequency heart rate variability (HF-HRV), a marker of vagally-mediated parasympathetic activity, has been conceptualized as a psychophysiological index of emotion regulation that may moderate individuals' responses to stress. Using a daily diary design, we tested whether individual differences in resting HF-HRV moderated the association between daily child-related stress and negative affect among a sample of 84 heterosexual couples with preschool-aged children. After controlling for participants' age, gender, socioeconomic status, employment status, and ethnicity, hierarchical linear modeling revealed that resting HF-HRV moderated both the between-person and within-person associations between self-reported child-related stress and daily negative affect. Between-person analyses indicated that the strength of the positive association between mean daily child stress and negative affect across the daily diary period increased with decreasing resting HF-HRV. Similarly, within-person analyses indicated that on days when participants reported more child-related stress than usual, the magnitude of the increase in negative affect on that day was inversely related to resting HF-HRV. Taken together, these findings suggest that lower resting HF-HRV may index vulnerability to stress-related disturbances in negative affect. This increased negative affective response to daily stress may be one pathway through which individuals with lower resting HF-HRV are at increased risk for depressive symptoms over time.

Implicit Affect, Heart Rate Variability, and the Metabolic Syndrome

OBJECTIVE

Greater negative affect has been associated with an increased risk of the metabolic syndrome (METs). However, all studies to date have examined this association using explicit affect measures based on subjective ratings of emotional experiences. Prior studies suggest that implicit affect, representing the automatic, prereflective appraisal process involved in conscious emotional experiences, is associated with physiological stress responses independent of explicit affect. Furthermore, low resting heart rate variability (HRV) may increase the risk of stress-related diseases. The goals of this study were to evaluate the associations between implicit and explicit affect and METs and to assess whether these associations were amplified by lower HRV.

METHODS

This secondary analysis of a larger study included 217 middle-aged women who completed measures of implicit affect, explicit affect, high-frequency HRV, and the different components of METs.

RESULTS

There was a significant interaction between implicit negative affect and HRV predicting METs (odds ratio = 0.57, 95% confidence interval = 0.35-0.92), such that the combination of higher implicit affect and lower HRV was associated with a greater likelihood of METs. Similarly, there was a main effect of implicit negative affect as well as an interaction between implicit negative affect and HRV on the lipid accumulation product (b (standard error) = -0.06 (0.02), 95% confidence interval = -0.11 to -0.02), a combination of waist circumference and triglycerides.

CONCLUSIONS

Higher implicit negative affect in the context of lower HRV may be related to a greater risk of METs. The present findings highlight the relevance of including implicit affect measures in psychosomatic medicine research.

Heart rate variability as a biobehavioral marker of diverse psychopathologies: A review and argument for an "ideal range"

Heart rate variability (HRV), a measure of the variability in intervals between subsequent heart beats, is now widely considered an index of emotion regulatory capacity and the ability to adapt flexibly to changing environmental demands. Abnormalities in HRV are implicated in a host of psychopathologies, making it a potentially powerful transdiagnostic biobehavioral change mechanism in treatment interventions. While most mental illnesses are associated with low HRV, eating disorders have been linked to elevated HRV. We examined 62 research articles on HRV in psychopathology to test the hypothesis that there is an "ideal range" of HRV that predicts optimal functioning. Relationships between symptom severity and parameters that quantify HRV were examined graphically. More extreme time-domain HRV measures, both high and low, were associated with psychopathology, whereas healthy controls displayed mid-range values. Findings preliminarily support the hypothesis that there is an "ideal range" of HRV that could be targeted in biofeedback interventions.

Childhood Adversity and Affective Touch Perception: A Comparison of United Kingdom Care Leavers and Non-care Leavers

In the United Kingdom, the most common reasons for a child to come under the care of social services are neglect and abuse. Such early childhood adversity is a risk factor for social-isolation and poor mental health in adulthood. Touch is a key channel for nurturing interactions, and previous studies have shown links between early somatosensory input, experience dependent neural plasticity, and later life emotional functioning. The aim of the present study was to test the relationship between childhood neglect/abuse and later life experiences, attitudes, and hedonic ratings of affective touch. Here, affective touch is defined as low force, dynamic touch which C-Tactile afferents (CTs) respond optimally to. We hypothesized that a childhood lacking in early nurturing tactile stimulation would be associated with reduced sensitivity to socially relevant affective touch in adulthood. To test this, 19 care leavers (average 9.32 ± 3.70 years in foster care) and 32 non-care leavers were recruited through opportunity sampling (mean age = 21.25 ± 1.74 years). Participants completed a range of psychophysical somatosensory tests. First, they rated the pleasantness of CT-optimal (3 cm/s) and non-CT-optimal (0.3 and 30 cm/s) stroking touch applied to their forearm, both robotically and by an experimenter. They also made vicarious ratings of the anticipated pleasantness of social tactile interactions depicted in a series of videos. Finally, they filled in the Childhood Trauma Questionnaire (CTQ) and the Touch Experiences and Attitudes Questionnaire (TEAQ). As expected, care leavers reported significantly higher levels of childhood trauma than the control group. They also reported significantly lower levels of positive childhood touch compared to non-care leavers, but their attitudes and experiences of current intimate and affiliative touch did not differ. Across all psychophysical tests, care leavers showed specific reduction in sensitivity to the affective value of CT targeted 3 cm/s touch. The results of this study support the hypothesis that a lack of nurturing touch in early developmental periods leads to blunted sensitivity to the specific social value of affective touch. Future research should investigate the neural and physiological mechanisms underlying the observed effect.

Neurophysiological responses to safety signals and the role of cardiac vagal control

BACKGROUND

Deficits in safety signal learning are well-established in fear-related disorders (e.g., PTSD, phobias). The current study used a fear conditioning paradigm to test associations among eye blink startle and event-related brain potential (ERP) latency measures of safety signal learning, as well as the role of cardiac vagal control (a measure of top-down inhibition necessary for safety learning).

METHODS

Participants were 49 trauma-exposed women ages 17 to 28 years. Eyeblink startle response and ERP amplitudes/latencies were derived for conditioned stimuli associated (CS+) and not associated (CS-) with an aversive unconditioned stimulus. ERPs included the P100 and late positive potential (LPP), which index early visual processing and sustained emotional encoding, respectively. Cardiac vagal control was assessed with resting heart rate variability (HRV).

RESULTS

P100 and LPP latencies for the CS- (safety signal stimulus) were significantly negatively associated with startle to the CS-, but not the CS + . LPP CS- latencies were significantly negatively associated with PTSD Intrusion scores, and this relationship was moderated by vagal control, such that the effect was only present among those with low HRV.

CONCLUSIONS

ERP-based markers of safety signal learning were associated with startle response to the CS- (but not CS+) and PTSD symptoms, indicating that these markers may have relevance for fear-related disorders. Cardiac vagal control indexed by HRV is a moderating factor in these associations and may be relevant to safety signal learning.

Heart Rate Variability as an Index of Differential Brain Dynamics at Rest and After Acute Stress Induction

The brain continuously receives input from the internal and external environment. Using this information, the brain exerts its influence on both itself and the body to facilitate an appropriate response. The dynamic interplay between the brain and the heart and how external conditions modulate this relationship deserves attention. In high-stress situations, synchrony between various brain regions such as the prefrontal cortex and the heart may alter. This flexibility is believed to facilitate transitions between functional states related to cognitive, emotional, and especially autonomic activity. This study examined the dynamic temporal functional association of heart rate variability (HRV) with the interaction between three main canonical brain networks in 38 healthy male subjects at rest and directly after a psychosocial stress task. A sliding window approach was used to estimate the functional connectivity (FC) among the salience network (SN), central executive network (CEN), and default mode network (DMN) in 60-s windows on time series of blood-oxygen-level dependent (BOLD) signal. FC between brain networks was calculated by Pearson correlation. A multilevel linear mixed model was conducted to examine the window-by-window association between the root mean square of successive differences between normal heartbeats (RMSSD) and FC of network-pairs across sessions. Our findings showed that the minute-by-minute correlation between the FC and RMSSD was significantly stronger between DMN and CEN than for SN and CEN in the baseline session [b = 4.36, t(5025) = 3.20, p = 0.006]. Additionally, this differential relationship between network pairs and RMSSD disappeared after the stress task; FC between DMN and CEN showed a weaker correlation with RMSSD in comparison to baseline [b = −3.35, t(5025) = −3.47, p = 0.006]. These results suggest a dynamic functional interplay between HRV and the functional association between brain networks that varies depending on the needs created by changing conditions.

Inertia of emotions and inertia of the heart: Physiological processes underlying inertia of negative emotions at work

Emotional inertia is a key feature of emotional dynamics and it refers to the degree to which a current emotional state can be predicted by a previous emotional state. In this study, using the experience sampling method, we examined the relationship between inertia of negative emotions at work and parasympathetic activity, measured by vagally-mediated heart rate variability (HRV). In line with current literature on HRV, we propose that temporal dependency of negative emotions at work may be associated to lower HRV, an important marker of the ability to flexibly adjust to a changing environment. Participants (n = 120) were prompted six times during a regular workday, while wearing a heart rate monitor. In accordance with the polyvagal theory and the model of neurovisceral integration, findings supported our hypothesis and indicated that workers with lower HRV tend to show high time persistence of negative emotions at work. Practical implications and directions for future research are discussed.

Heart rate variability as a biomarker in health and affective disorders: A perspective on neuroimaging studies

The dynamic embodiment of psychological processes is evident in the association of health outcomes, behavioural traits and psychological functioning with Heart Rate Variability (HRV). The dominant high-frequency component of HRV is an index of the central neural control of heart rhythm, mediated via the parasympathetic vagus nerve. HRV provides a potential objective measure of action policies for the adaptive and predictive allostatic regulation of homeostasis within the cardiovascular system. In its support, a network of brain regions (referred to as the 'central autonomic network') maps internal state, and controls autonomic responses. This network includes regions of prefrontal cortex, anterior cingulate cortex, insula, amygdala, periaqueductal grey, pons and medulla. Human neuroimaging studies of neural activation and functional connectivity broadly endorse this architecture, and its link with cardiac regulation at rest and dysregulation in clinical states that include affective disorders. In this review, we appraise neuroimaging research and related evidence for HRV as an informative marker of autonomic integration with affect and cognition, taking a perspective on function and organisation. We consider evidence for the utility of HRV as a metric to inform targeted interventions to improve autonomic and affective dysregulation, and suggest research questions for further investigation.

Resting heart rate variability is negatively associated with mirror neuron and limbic response to emotional faces

Whether neurovisceral integration, reflected by resting high-frequency heart rate variability (HRV), constrains or facilitates neural reactivity to other people's emotions is unclear. We assessed the relation between resting HRV and neural activation when observing and imitating emotional faces. We focused on brain regions implicated in sensorimotor resonance, salience detection and arousal. We used electrocardiogram data to compute resting HRV. Resting HRV measures were negatively correlated with activation in a portion of the inferior frontal gyrus showing mirror neuron properties, the insula and the amygdala in response to observation, but not imitation, of emotional faces. Thus, resting HRV appears to be linked to sensitivity to others' emotional cues, both in terms of the tendency to map others' emotional facial expressions onto one's own motor system and to rapidly detect and mark others' emotions as salient events. Resting HRV may reflect, in part, a threshold for increased processing of others' emotional cues.

Rumination Moderates the Association Between Resting High-Frequency Heart Rate Variability and Perceived Ethnic Discrimination

Abstract. Ethnic discrimination (ED) is both an unfortunate and uncontrollable phenomenon that uniquely impacts African Americans (AAs) and other individuals of ethnic minority status. Perceived ethnic discrimination (PED), defined as the degree to which an individual consciously perceives a negative event as discriminatory and threatening, largely determines the impact that ED can have on target individuals. However, research has not yet considered how individual differences in both emotion regulation abilities, as indexed by resting high-frequency heart rate variability (HF-HRV), and rumination, a maladaptive emotion regulation strategy, may predict PED in AAs. The following investigation examined this relationship in a sample of 101 college-aged students (45 AAs and 56 Caucasian Americans). Resting HF-HRV was assessed via electrocardiogram during a 5-minute-resting period. Rumination was assessed using the ruminative responses scale and everyday PED was assessed using the perceived ethnic discrimination questionnaire. Results showed a significant negative relationship between resting HF-HRV and PED in AAs only. Rumination significantly moderated this relationship, such that lower HF-HRV was related to higher PED only in AAs who reported moderate to higher, β = 0.417 (0.125), p < .01, levels of trait rumination. These results suggest that greater HF-HRV and lesser ruminative tendencies are key factors in reducing PED and therefore possibly, negative consequences associated with ED.

High-Frequency Heart Rate Variability Reactivity and Trait Worry Interact to Predict the Development of Sleep Disturbances in Response to a Naturalistic Stressor

BACKGROUND

High-frequency heart rate variability (HF-HRV) reactivity was proposed as a vulnerability factor for stress-induced sleep disturbances. Its effect may be amplified among individuals with high trait worry or sleep reactivity.

PURPOSE

This study evaluated whether HF-HRV reactivity to a worry induction, sleep reactivity, and trait worry predict increases in sleep disturbances in response to academic stress, a naturalistic stressor.

METHOD

A longitudinal study following 102 undergraduate students during an academic semester with well-defined periods of lower and higher academic stress was conducted. HF-HRV reactivity to a worry induction, trait worry using the Penn State Worry Questionnaire, and sleep reactivity using the Ford Insomnia Stress Reactivity Test were measured during the low stress period. Sleep disturbances using the Pittsburgh Sleep Quality Index were assessed twice during the lower stress period and three times during the higher stress period.

RESULTS

Greater reductions in HF-HRV in response to the worry induction predicted increases in sleep disturbances from the lower to the higher academic stress period. Trait worry moderated this association: individuals with both higher trait worry and greater HF-HRV reactivity to worry had larger increases in stress-related sleep disturbances over time, compared to participants with lower trait worry and HF-HRV reactivity. A similar, but marginally significant effect was found for sleep reactivity.

CONCLUSION

This study supports the role of HF-HRV reactivity as a vulnerability factor for stress-induced sleep disturbances. The combination of high trait worry and high HF-HRV reactivity to worry might identify a subgroup of individuals most vulnerable to stress-related sleep disturbances.

Fractal dimension of EEG signals and heart dynamics in discrete emotional states

In this study, we explored the fractal dimension (FD; a measure of signal complexity) of 28 EEG channels with positive and negative emotional states. The EEG of participants and their ECG were registered while watching short video clips that induced fear, disgust, humour, or neutral emotions. In order to better understand the nature of these emotions, the Higuchi FD of EEG segments and the heart rate variability (HRV) of the ECG associated with each emotion were obtained. Our results exhibited similar patterns of results with both measures. Humour elicited the highest FD scores in most EEG channels and the highest HRV, while fear, among all emotions, produced the lowest scores in both measures. These results may contribute to the understanding of the relationship between cortical and heart dynamics and their role on emotion perception.

Reduced self-regulation mirrors the distorting effects of burnout symptomatology on task difficulty perception during an inhibition task

Burnout, a pathological consequence of chronic work stress, shows an increasing incidence rate in industrialized countries. Previous findings indicate that burnout may be linked to a detachment of the negative association between subjectively appraised task demand and cognitive performance, which is typically seen in healthy individuals. The present study sought to confirm this relationship and to investigate whether this dissociation is mirrored in a biological marker of self-regulation, i.e., resting vagally mediated heart rate variability (HRV). A heterogeneous sample (N = 65) of working adults (M age = 43.3, SD = 10; 23.1 % male) with varying degrees of burnout symptomatology completed three cognitive tasks (2-back, number-letter, and go/nogo) to assess different domains of executive functioning (updating, set-shifting, and inhibition), and respective demand ratings. Additionally, vagally mediated HRV at rest, operationalized as the root-mean square differences of successive R-R intervals (RMSSD), was recorded. Burnout symptomatology moderated the association between subjective task difficulty and performance parameters of the go/nogo task, such that higher burnout scores were associated with reductions in the naturally occurring negative association between self-rated task demand and response inhibition. Intriguingly, this pattern was mirrored when replacing burnout with HRV. These findings suggest that burnout symptomatology, and individual differences in self-regulatory capacities (indexed by resting HRV), may alter one's capacity for accurate task evaluation, a mechanism which could potentially underlie the dissociation between self-rated cognitive function and actual performance among individuals experiencing burnout.

Startling Differences: Using the Acoustic Startle Response to Study Sex Differences and Neurosteroids in Affective Disorders

PURPOSE OF REVIEW

Neuroactive steroid hormones, such as estradiol and progesterone, likely play a role in the pathophysiology of female-specific psychiatric disorders such as premenstrual dysphoric disorder (PMDD) and postpartum depression and may contribute to the marked sex differences observed in the incidence and presentation of affective disorders. However, few tools are available to study the precise contributions of these neuroactive steroids (NSs). In this review, we propose that the acoustic startle response (ASR), an objective measure of an organism's response to an emotional context or stressor, is sensitive to NSs. As such, the ASR represents a unique translational tool that may help to elucidate the contribution of NSs to sex differences in psychiatric disorders.

RECENT FINDINGS

Findings suggest that anxiety-potentiated startle (APS) and prepulse inhibition of startle (PPI) are the most robust ASR paradigms for assessing contribution of NSs to affective disorders, while affective startle response modulation (ASRM) appears less diagnostic of sex or menstrual cycle (MC) effects. However, few studies have appropriately used ASR to test a priori hypotheses about sex or MC differences. We recommend that ASR studies account for sex as a biological variable (SABV) and hormonal status to further knowledge of NS contribution to affective disorders.

Serotonin receptor 1A promoter polymorphism, rs6295, modulates human anxiety levels via altering parasympathetic nervous activity

OBJECTIVE

The G-allele of the -1019C/G (rs6295) promoter polymorphism of the serotonin receptor 1A (HTR1A) gene has been implicated in anxiety; however, the underlying neurophysiological processes are still not fully understood. Recent evidence indicates that low parasympathetic (vagal) tone is predictive of anxiety. We thus conducted a structural equation model (SEM) to examine whether the HTR1A rs6295 variant can affect anxiety by altering parasympathetic nervous activity.

METHOD

A sample of 1141 drug-free healthy Han Chinese was recruited for HTR1A genotyping. Autonomic nervous function was assessed by short-term spectral analysis of heart rate variability (HRV). Anxiety and stress levels were evaluated by the Beck Anxiety Inventory (BAI) and the Perceived Stress Scale (PSS) respectively.

RESULTS

The number of the HTR1A G allele was inversely correlated with high-frequency power (HF), a parasympathetic index of HRV. The HF index was negatively associated with BAI scores. Furthermore, the good-fitting SEM, adjusting for confounding variables (e.g., age and PSS levels), revealed a significant pathway linking rs6295 variant to BAI scores via HF index modulation.

CONCLUSION

These results are the first to show that HTR1A -1019C/G polymorphism influences anxiety levels by modulating parasympathetic tone, providing a neurophysiological insight into the role of HTR1A in human anxiety.

Cardiac vagal control as a marker of emotion regulation in healthy adults: A review

In the last two decades, a growing body of theory and research has targeted the role of cardiac vagal control (CVC) in emotional responding. This research has either focused on resting CVC (also denoted as cardiac vagal tone) or phasic changes in CVC (also denoted as vagal reactivity) in response to affective stimuli. The present paper is aimed at reporting a review of the papers published between 1996 and 2016, and focused on the results of 135 papers examining cardiac vagal control as a physiological marker of emotion regulation in healthy adults. The review shows that studies have employed a wide array of methodologies and measures, often leading to conflicting results. High resting CVC has been associated with better down-regulation of negative affect, use of adaptive regulatory strategies, and more flexible emotional responding. Concerning phasic changes, research has consistently found decreased CVC in response to stress, while CVC increases have been shown to reflect either self-regulatory efforts or recovery from stress. Despite conflicting results, we conclude that existing literature supports the use of CVC as a noninvasive, objective marker of emotion regulation.

Context Processing and the Neurobiology of Post-Traumatic Stress Disorder

Progress in clinical and affective neuroscience is redefining psychiatric illness as symptomatic expression of cellular/molecular dysfunctions in specific brain circuits. Post-traumatic stress disorder (PTSD) has been an exemplar of this progress, with improved understanding of neurobiological systems subserving fear learning, salience detection, and emotion regulation explaining much of its phenomenology and neurobiology. However, many features remain unexplained and a parsimonious model that more fully accounts for symptoms and the core neurobiology remains elusive. Contextual processing is a key modulatory function of hippocampal-prefrontal-thalamic circuitry, allowing organisms to disambiguate cues and derive situation-specific meaning from the world. We propose that dysregulation within this context-processing circuit is at the core of PTSD pathophysiology, accounting for much of its phenomenology and most of its biological findings. Understanding core mechanisms like this, and their underlying neural circuits, will sharpen diagnostic precision and understanding of risk factors, enhancing our ability to develop preventive and "personalized" interventions.

Effects of visual flow direction on signs and symptoms of cybersickness

Our objective was to assess the influence of visual flow direction on physiological changes and symptoms elicited by cybersickness. Twelve healthy subjects (6 male and 6 female) were exposed to a 15-min virtual ride on a rollercoaster on two different days in a counterbalanced manner, such half of participants were facing forward during the first ride while another half was facing backward. Forehead skin conductance, heart rate and HRV parameters (SDRR, RMSSD) were collected as objective measures; subjective symptoms were assessed with the Motion Sickness Assessment Questioner immediately after exposure. We found that while nausea ratings at which participants terminated the experiment did not differ between forward/backward rides, the mean ride tolerance time was significantly longer during reverse ride compared to forward ride (6.1±0.4 vs 5.0±0.5 min, respectively, p = 0.01, η² = 0.45). Analysis of HRV parameters revealed significant reduction in both RMSSD (p = 0.02, t = 2.62, η2 = 0.43) and SDRR (p = 0.01, t = 2.90, η2 = 0.45) in the forward ride; no such changes were found in the backward ride. We also found that amplitude of phasic changes in forehead skin conductance increased significantly in both ride directions. This increase however was significantly lower (p<0.05) in backward ride when compared to the forward ride. When assessed immediately post-ride, subjects reported significantly lower (p = 0.04) subjective symptom intensity after the reverse ride compared to the forward ride. We conclude that the direction of visual flow has a significant effect on the symptoms reported by the subjects and on the physiological changes during cybersickness.

Emotion dysregulation in alexithymia: Startle reactivity to fearful affective imagery and its relation to heart rate variability

Alexithymia is associated with deficiencies in recognizing and expressing emotions and impaired emotion regulation, though few studies have verified the latter assertion using objective measures. This study examined startle reflex modulation by fearful imagery and its associations with heart rate variability in alexithymia. Fifty-four adults (27 alexithymic) imagined previously normed fear scripts. Startle responses were assessed during baseline, first exposure, and reexposure. During first exposure, participants, in separate trials, engaged in either shallow or deep emotion processing, giving emphasis on descriptive or affective aspects of imagery, respectively. Resting heart rate variability was assessed during 2 min of rest prior to the experiment, with high alexithymic participants demonstrating significantly higher LF/HF (low frequency/high frequency) ratio than controls. Deep processing was associated with nonsignificantly larger and faster startle responses at first exposure for alexithymic participants. Lower LF/HF ratio, reflecting higher parasympathetic cardiac activity, predicted greater startle amplitude habituation for alexithymia but lower habituation for controls. Results suggest that, when exposed to prolonged threat, alexithymics may adjust poorly, showing a smaller initial defensive response but slower habituation. This pattern seems related to their low emotion regulation ability as indexed by heart rate variability.

The hierarchical basis of neurovisceral integration

The neurovisceral integration (NVI) model was originally proposed to account for observed relationships between peripheral physiology, cognitive performance, and emotional/physical health. This model has also garnered a considerable amount of empirical support, largely from studies examining cardiac vagal control. However, recent advances in functional neuroanatomy, and in computational neuroscience, have yet to be incorporated into the NVI model. Here we present an updated/expanded version of the NVI model that incorporates these advances. Based on a review of studies of structural/functional anatomy, we first describe an eight-level hierarchy of nervous system structures, and the contribution that each level plausibly makes to vagal control. Second, we review recent work on a class of computational models of brain function known as "predictive coding" models. We illustrate how the computational dynamics of these models, when implemented within our proposed vagal control hierarchy, can increase understanding of the relationship between vagal control and both cognitive performance and emotional/physical health. We conclude by discussing novel implications of this updated NVI model for future research.

Desynchronization of autonomic response and central autonomic network connectivity in posttraumatic stress disorder

OBJECTIVES

Although dysfunctional emotion regulatory capacities are increasingly recognized as contributing to posttraumatic stress disorder (PTSD), little work has sought to identify biological markers of this vulnerability. Heart rate variability (HRV) is a promising biomarker that, together with neuroimaging, may assist in gaining a deeper understanding of emotion dysregulation in PTSD. The objective of the present study was, therefore, to characterize autonomic response patterns, and their related neuronal patterns in individuals with PTSD at rest.

METHODS

PTSD patients (N = 57) and healthy controls (N = 41) underwent resting-state fMRI. Connectivity patterns of key regions within the central autonomic network (CAN)-including the ventromedial prefrontal cortex (vmPFC), amygdala, and periaqueductal gray (PAG)-were examined using a seed-based approach. Observed connectivity patterns were then correlated to resting HRV.

RESULTS

In contrast to controls, individuals with PTSD exhibited lower HRV. In addition, whereas controls engaged a localized connectivity pattern of CAN-related brain regions, in PTSD, key CAN regions were associated with widespread connectivity patterns in regions related to emotional reactivity (vmPFC and amygdala to insular cortex and lentiform nucleus; PAG to insula) and motor readiness (vmPFC and amygdala to precentral gyrus; PAG to precentral gyrus and cerebellum). Critically, whereas CAN connectivity in controls was strongly related to higher HRV (insula, mPFC, superior frontal cortex, thalamus), HRV covariation was absent in PTSD subjects.

CONCLUSIONS

This study provides the first evidence for a specific psychophysiological-neuronal profile in PTSD individuals characterized by lower resting HRV and a lack of HRV covariation with CAN-related brain connectivity. Hum Brain Mapp 38:27-40, 2017. © 2016 Wiley Periodicals, Inc.

Exposed to events that never happen: Generalized unsafety, the default stress response, and prolonged autonomic activity

Based on neurobiological and evolutionary arguments, the generalized unsafety theory of stress (GUTS) hypothesizes that the stress response is a default response, and that chronic stress responses are caused by generalized unsafety (GU), independent of stressors or their cognitive representation. Three highly prevalent conditions are particularly vulnerable to becoming 'compromised' in terms of GU, and carry considerable health risks: Thus, GUTS critically revises and expands stress theory, by focusing on safety instead of threat, and by including risk factors that have hitherto not been attributed to stress.

The default response to uncertainty and the importance of perceived safety in anxiety and stress: An evolution-theoretical perspective

From a combined neurobiological and evolution-theoretical perspective, the stress response is a subcortically subserved response to uncertainty that is not 'generated' but 'default': the stress response is 'always there' but as long as safety is perceived, the stress response is under tonic prefrontal inhibition, reflected by high vagally mediated heart rate variability. Uncertainty of safety leads to disinhibiting the default stress response, even in the absence of threat. Due to the stress response's survival value, this 'erring on the side of caution' is passed to us via our genes. Thus, intolerance of uncertainty is not acquired during the life cycle, but is a given property of all living organisms, only to be alleviated in situations of which the safety is learned. When the latter is deficient, generalized unsafety ensues, which underlies chronic anxiety and stress and their somatic health risks, as well as other highly prevalent conditions carrying such risks, including loneliness, obesity, aerobic unfitness and old age.

Heart rate variability is associated with amygdala functional connectivity with MPFC across younger and older adults

The ability to regulate emotion is crucial to promote well-being. Evidence suggests that the medial prefrontal cortex (mPFC) and adjacent anterior cingulate (ACC) modulate amygdala activity during emotion regulation. Yet less is known about whether the amygdala-mPFC circuit is linked with regulation of the autonomic nervous system and whether the relationship differs across the adult lifespan. The current study tested the hypothesis that heart rate variability (HRV) reflects the strength of mPFC-amygdala interaction across younger and older adults. We recorded participants' heart rates at baseline and examined whether baseline HRV was associated with amygdala-mPFC functional connectivity during rest. We found that higher HRV was associated with stronger functional connectivity between the amygdala and the mPFC during rest across younger and older adults. In addition to this age-invariant pattern, there was an age-related change, such that greater HRV was linked with stronger functional connectivity between amygdala and ventrolateral PFC (vlPFC) in younger than in older adults. These results are in line with past evidence that vlPFC is involved in emotion regulation especially in younger adults. Taken together, our results support the neurovisceral integration model and suggest that higher heart rate variability is associated with neural mechanisms that support successful emotional regulation across the adult lifespan.

Prospective Associations between Emotion Dysregulation and Fear-Potentiated Startle: The Moderating Effect of Respiratory Sinus Arrhythmia

Background: Emotion dysregulation has been implicated in the negative outcomes following trauma exposure. A proposed biomarker of emotion dysregulation, respiratory sinus arrhythmia (RSA), has demonstrated associations with trauma-related phenomena, such as the fear-potentiated startle (FPS) response. The current study aimed to examine the prospective association between emotion dysregulation and RSA and FPS several years following trauma exposure.

Methods: Participants were 131 women exposed to a campus mass shooting on February 14, 2008. Pre-shooting emotion dysregulation was assessed in 2006–2008. Startle response, measured by orbicularis oculi electromyography (EMG), and RSA were gathered during an FPS paradigm conducted from 2012 to 2015.

Results: No significant associations among emotion dysregulation, RSA, and FPS emerged among the full sample. However, emotion dysregulation predicted FPS during both acquisition (r = 0.40, p < 0.05) and extinction (r = 0.57, p < 0.01) among individuals with high resting RSA.

Conclusions: Findings suggest that pre-shooting emotion dysregulation is a potent predictor of FPS several years following potential trauma exposure, and this association varies by RSA level. Results emphasize the importance of examining autonomic regulation in the association between emotion dysregulation and recovery from trauma exposure.

Neural correlates of individual differences in anxiety sensitivity: an fMRI study using semantic priming

Individuals with high anxiety sensitivity (AS) have an increased risk of developing anxiety disorders and are more biased in how they process fear-related stimuli. This study investigates the neural correlates of fear-related words and word associations in high- and low-AS individuals. We used a semantic priming paradigm during functional magnetic resonance imaging in which three types of target words (fear symptoms, e.g. 'dizziness'; neutral, e.g. 'drink'; and pseudowords, e.g. 'salkom') were preceded by two types of prime words (fear-triggers, e.g. 'elevator'; and neutral, e.g. 'bottle'). Subjects with high AS rated fear-symptom words (vs neutral words) as more unpleasant than low-AS individuals; they also related these words more strongly to fear-triggers and showed prolonged reaction times. During the processing of fear-symptom words, greater activation in the left anterior insula was observed in high-AS subjects than in low-AS subjects. Lower activation in the left inferior frontal gyrus, angular gyrus, fusiform gyrus and bilateral amygdalae was found in high-AS subjects when fear-symptom words were preceded by fear-trigger words. The findings suggest that cognitive biases and the anterior insula play a crucial role in high-AS individuals. Furthermore, semantic processes may contribute to high AS and the risk of developing anxiety disorders.

Autonomic nervous system dysfunction in psychiatric disorders and the impact of psychotropic medications: a systematic review and meta-analysis

BACKGROUND

Autonomic nervous system (ANS) dysfunction is a putative underlying mechanism for increased cardiovascular disease risk in individuals with psychiatric disorders. Previous studies suggest that this risk may be related to psychotropic medication use. In the present study we systematically reviewed and analyzed published studies of heart rate variability (HRV), measuring ANS output, to determine the effect of psychiatric illness and medication use.

METHODS

We searched for studies comparing HRV in physically healthy adults with a diagnosed psychiatric disorder to controls and comparing HRV pre- and post-treatment with a psychotropic medication.

RESULTS

In total, 140 case-control (mood, anxiety, psychosis, dependent disorders, k = 151) and 30 treatment (antidepressants, antipsychotics; k = 43) studies were included. We found that HRV was reduced in all patient groups compared to controls (Hedges g = -0.583) with a large effect for psychotic disorders (Hedges g = -0.948). Effect sizes remained highly significant for medication-free patients compared to controls across all disorders. Smaller and significant reductions in HRV were observed for specific antidepressants and antipsychotics.

LIMITATIONS

Study quality significantly moderated effect sizes in case-control analyses, underscoring the importance of assessing methodological quality when interpreting HRV findings.

CONCLUSION

Combined findings confirm substantial reductions in HRV across psychiatric disorders, and these effects remained significant even in medication-free individuals. Reductions in HRV may therefore represent a significant mechanism contributing to elevated cardiovascular risk in individuals with psychiatric disorders. The negative impact of specific medications on HRV suggest increased risk for cardiovascular disease in these groups, highlighting a need for treatment providers to consider modifiable cardiovascular risk factors to attenuate this risk.

Lower Resting State Heart Rate Variability Relates to High Pain Catastrophizing in Patients with Chronic Whiplash-Associated Disorders and Healthy Controls

Vagally mediated heart rate variability (vmHRV) is widely respected as a psychophysiological measure of emotion regulation capacity and serves as a readily available index of executive brain areas that exert an inhibitory influence on subcortical structures. Pain catastrophizing (PC) is conceptualized as the tendency to misinterpret and exaggerate pain-related situations that may be threatening. Chronic pain patients show lower vmHRV and higher PC. Previously, no study has investigated the association of PC and vmHRV. We examined the association of PC and vmHRV in a sample of patients with chronic whiplash-associated disorders (WAD, n = 30) and healthy controls (n = 31). Patients with WAD showed lower vmHRV, indexed by high-frequency HRV (effect size, Cohen's d = 0.442), and greater PC (d = 0.815). Zero-order and partial correlations controlling for age and sex revealed that vmHRV and PC are inversely related. The results provide evidence for a psychophysiological mechanism underlying PC, in particular in chronic pain patients.

Integrating affective and cognitive correlates of heart rate variability: A structural equation modeling approach

High frequency heart rate variability (HRV) is a measure of neurocardiac communication thought to reflect predominantly parasympathetic cardiac regulation. Low HRV has been associated empirically with clinical and subclinical levels of anxiety and depression and, more recently, high levels of HRV have been associated with better performance on some measures of executive functioning (EF). These findings have offered support for theories proposing HRV as an index measure of a broad, self-regulatory capacity underlying aspects of emotion regulation and executive control. This study sought to test that proposition by using a structural equation modeling approach to examine the relationships of HRV to negative affect (NA) and EF in a large sample of U.S. adults ages 30s-80s. HRV was modeled as a predictor of an NA factor (self-reported trait anxiety and depression symptoms) and an EF factor (performance on three neuropsychological tests tapping facets of executive abilities). Alternative models also were tested to determine the utility of HRV for predicting NA and EF, with and without statistical control of demographic and health-related covariates. In the initial structural model, HRV showed a significant positive relationship to EF and a nonsignificant relationship to NA. In a covariate-adjusted model, HRV's associations with both constructs were nonsignificant. Age emerged as the only significant predictor of NA and EF in the final model, showing inverse relationships to both. Findings may reflect population and methodological differences from prior research; they also suggest refinements to the interpretations of earlier findings and theoretical claims regarding HRV.