Heart rate variability, the vagus and calm.
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551 to 575 of 1,007The auriculo-vagal afferent pathway and its role in seizure suppression in rats.
Background: The afferent projections from the auricular branch of the vagus nerve (ABVN) to the nucleus tractus solitaries (NTS) have been proposed as the anatomical basis for the increased parasympathetic tone seen in auriculo-vagal reflexes. As the afferent center of the vagus nerve, the NTS has been considered to play roles in the anticonvulsant effect of cervical vagus nerve stimulation (VNS). Here we proposed an "auriculo-vagal afferent pathway" (AVAP), by which transcutaneous auricular vagus nerve stimulation (ta-VNS) suppresses pentylenetetrazol (PTZ)-induced epileptic seizures by activating the NTS neurons in rats.
Results: The afferent projections from the ABVN to the NTS were firstly observed in rats. ta-VNS increased the first grand mal latency of the epileptic seizure and decreased the seizure scores in awake rats. Furthermore, when the firing rates of the NTS neurons decreas…
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High-resolution measurement of electrically-evoked vagus nerve activity in the anesthetized dog.
Objective: Not fully understanding the type of axons activated during vagus nerve stimulation (VNS) is one of several factors that limit the clinical efficacy of VNS therapies. The main goal of this study was to characterize the electrical recruitment of both myelinated and unmyelinated fibers within the cervical vagus nerve.
Approach: In anesthetized dogs, recording nerve cuff electrodes were implanted on the vagus nerve following surgical excision of the epineurium. Both the vagal electroneurogram (ENG) and laryngeal muscle activity were recorded in response to stimulation of the right vagus nerve.
Main results: Desheathing the nerve significantly increased the signal-to-noise ratio of the ENG by 1.2 to 9.9 dB, depending on the nerve fiber type. Repeated VNS following nerve transection or neuromuscular block (1) enabled the characterization of A-fibers, two sub-types of B-fibers, and u…
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Rosas-Ballina M, Olofsson PS, Ochani M, Valdés-Ferrer SI, Levine YA, Reardon C, Tusche MW, Pavlov VA, Andersson U, Chavan S, Mak TW, Tracey KJ (2011)MEDLINE-indexed journal, not yet read by usScience (New York, N.Y.)1,169 citations Acetylcholine-synthesizing T cells relay neural signals in a vagus nerve circuit.
Neural circuits regulate cytokine production to prevent potentially damaging inflammation. A prototypical vagus nerve circuit, the inflammatory reflex, inhibits tumor necrosis factor-α production in spleen by a mechanism requiring acetylcholine signaling through the α7 nicotinic acetylcholine receptor expressed on cytokine-producing macrophages. Nerve fibers in spleen lack the enzymatic machinery necessary for acetylcholine production; therefore, how does this neural circuit terminate in cholinergic signaling? We identified an acetylcholine-producing, memory phenotype T cell population in mice that is integral to the inflammatory reflex. These acetylcholine-producing T cells are required for inhibition of cytokine production by vagus nerve stimulation. Thus, action potentials originating in the vagus nerve regulate T cells, which in turn produce the neurotransmitter, acetylcholine, requi…
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Meregnani J, Clarençon D, Vivier M, Peinnequin A, Mouret C, Sinniger V, Picq C, Job A, Canini F, Jacquier-Sarlin M, Bonaz B (2011)MEDLINE-indexed journal, not yet read by usAutonomic neuroscience : basic & clinical216 citations Anti-inflammatory effect of vagus nerve stimulation in a rat model of inflammatory bowel disease.
Vagus nerve stimulation of afferents is used as an adjunctive treatment for drug-resistant epilepsy and depression. In addition, anti-inflammatory properties of vagus nerve stimulation have been reported in various experimental models of inflammation but not in colitis. These effects are thought to be mediated via peripheral release of acetylcholine from the vagus and subsequent activation of macrophages. Our aim was to evaluate in rats the anti-inflammatory effects of chronic vagus nerve stimulation on colonic inflammation. Colitis was induced by intracolonic instillation of trinitrobenzene sulfonic acid. Vagus nerve stimulation (left cervical) was performed in freely moving animals 3 h per day for five consecutive days. Assessment of colonic inflammation was obtained using physiological (e.g. body weight, temperature and locomotor activity) parameters, macroscopical (area of lesions), …
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Pilot Study of a Single Session Heart Rate Variability Biofeedback Intervention on Veterans' Posttraumatic Stress Symptoms.
Veterans with posttraumatic stress symptoms exhibit reduced heart rate variability characteristic of autonomic nervous system dysregulation. Studies show heart rate variability biofeedback (HRVB) is effective in reducing posttraumatic stress symptoms by improving autonomic functioning. Participants in this pilot study were veterans of different war eras with military-related posttraumatic stress symptoms. The study aims were to examine the impact of a single session HRVB intervention on posttraumatic stress symptoms and heart rate variability, test persistence of effects, and determine if veterans would find the intervention acceptable. One group (n = 6) received training in diaphragmatic breathing and heart rate variability biofeedback, augmented by twice-daily practice using a smart phone and breath pacing app. A second group (n = 6) received only a single session of diaphragmatic brea…
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Effect of an eight-week smartphone-guided HRV-biofeedback intervention on autonomic function and impulsivity in healthy controls.
A large body of scientific studies suggest a close relationship between increased vagal function and better cognitive performance.
Objective: In the current study, we investigated the association between autonomic function and behavioral impulsivity. We hypothesized that heart rate variability (HRV) biofeedback training increases HRV and enhances inhibitory control.
Approach: A total of 28 healthy participants were recruited. After drop-out, 14 participants completed an eight-week HRV biofeedback training with five training sessions per week including one session at the clinic's laboratory and four sessions at home using a mobile application running on their smartphone. Ten control subjects matched with respect to age and gender played a mobile game according to the same schedule as the biofeedback group. The assessment of autonomic status and the stop-signal task were conducted before t…
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Effect of short-term heart rate variability biofeedback on long-term abstinence in alcohol dependent patients - a one-year follow-up.
Background: A randomized controlled study (RCT) recently showed that short-term heart rate variability (HRV) biofeedback in addition to standard rehabilitation care for alcohol dependence can reduce craving, anxiety and improve cardiovascular autonomic function. In this one-year follow-up study we aimed to explore whether completion of 2-week HRV-Biofeedback training is associated with long-term abstinence. Furthermore, we sought to identify potential predictors of post-treatment abstinence.
Methods: We conducted a survey on abstinence in patients with alcohol dependence 1 year after completion of an RCT comparing HRV-biofeedback in addition to inpatient rehabilitation treatment alone (controls). Abstinence rates were compared and analysed for association with demographic data as well as psychometric and autonomic cardiac assessment before and after completion of the biofeedback training…
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Neurostructural abnormalities associated with axes of emotion dysregulation in generalized anxiety.
Background: Despite the high prevalence of generalized anxiety disorder (GAD) and its negative impact on society, its neurobiology remains obscure. This study characterizes the neurostructural abnormalities associated with key symptoms of GAD, focusing on indicators of impaired emotion regulation (excessive worry, poor concentration, low mindfulness, and physiological arousal).
Methods: These domains were assessed in 19 (16 women) GAD patients and 19 healthy controls matched for age and gender, using questionnaires and a low demand behavioral task performed before and after an induction of perseverative cognition (i.e. worry and rumination). Continuous pulse oximetry was used to measure autonomic physiology (heart rate variability; HRV). Observed cognitive and physiological changes in response to the induction provided quantifiable data on emotional regulatory capacity. Participants unde…
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Neural Responses to Heartbeats in the Default Network Encode the Self in Spontaneous Thoughts.
Unlabelled: The default network (DN) has been consistently associated with self-related cognition, but also to bodily state monitoring and autonomic regulation. We hypothesized that these two seemingly disparate functional roles of the DN are functionally coupled, in line with theories proposing that selfhood is grounded in the neural monitoring of internal organs, such as the heart. We measured with magnetoencephalograhy neural responses evoked by heartbeats while human participants freely mind-wandered. When interrupted by a visual stimulus at random intervals, participants scored the self-relatedness of the interrupted thought. They evaluated their involvement as the first-person perspective subject or agent in the thought ("I"), and on another scale to what degree they were thinking about themselves ("Me"). During the interrupted thought, neural responses to heartbeats in two regions…
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Novel heart rate parameters for the assessment of autonomic nervous system function in premature infants.
Autonomic nervous system (ANS) balance is a key factor in homeostatic control of cardiac activity, breathing and certain reflex reactions such as coughing, sneezing and swallowing and thus plays a crucial role for survival. ANS impairment has been related to many neonatal pathologies, including sudden infant death syndrome (SIDS). Moreover, some conditions have been identified as risk factors for SIDS, such as prone sleep position. There is an urgent need for timely and non-invasive assessment of ANS function in at-risk infants. Systematic measurement of heart rate variability (HRV) offers an optimal approach to access indirectly both sympathetic and parasympathetic influences on ANS functioning. In this paper, data from premature infants collected in a sleep physiology laboratory in the NICU are presented: traditional and novel approaches to HRV analyses are applied and compared in orde…
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Neurobiological substrates of cognitive rigidity and autonomic inflexibility in generalized anxiety disorder.
Generalized anxiety disorder (GAD) is characterized by difficulties in inhibiting both perseverative thoughts (worry and rumination) and autonomic arousal. We investigated the neurobiological substrates of such abnormal inhibitory processes, hypothesizing aberrant functional coupling within 'default mode' (DMN) and autonomic brain networks. Functional imaging and heart rate variability (HRV) data were acquired from GAD patients and controls during performance of three tracking tasks interspersed with a perseverative cognition (PC) induction. After detection of infrequent target stimuli, activity within putative DMN hubs was suppressed, consistent with a redirection of attentional resources from internal to external focus. This magnitude of activity change was attenuated in patients and individuals with higher trait PC, but was predicted by individual differences in HRV. Following the ind…
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Associations among integrated psychoneuroimmunological factors and metabolic syndrome.
Background: Metabolic syndrome (MetS) has been reported to cause considerable psychoneuroimmunology (PNI) disturbances such as, psychological distress, autonomic nervous imbalance, and impaired immune function. Associations among these psychoneuroimmunology (PNI) factors and their integrated effects with MetS and risk components of MetS necessitate further exploration.
Objective: This study investigated associations among psychoneuroimmunological factors, their integrated effects with MetS and risk components of MetS.
Methods: This was a cross-sectional study. Participants were recruited from two health management centers at a medical center in Northern Taiwan. Demographics and data on psychological distress (e.g., perceived stress and depression) were collected using self-reported questionnaires. Heart rate variability (HRV) and C-reactive protein values (CRP) were measured to evaluate …
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Abbreviated Resonant Frequency Training to Augment Heart Rate Variability and Enhance On-Demand Emotional Regulation in Elite Sport Support Staff.
Support and management staff in elite sport experience work-related stress and emotional disturbance to a similar extent as athletes (Fletcher and Wagstaff 2009). The resonant frequency breathing technique (Lehrer et al. 2000) can inhibit autonomic changes associated with stressful situations or events and as such provides a potential emotional regulation tool. The present study utilised five practitioner-led heart rate variability (HRV) biofeedback sessions and home practice via mobile applications to train support and management staff (n = 9) in resonant frequency breathing techniques. Although baseline HRV did not change from pre to post training, participants increased total HRV (i.e., SDNN; p = .006), parasympathetic HRV (i.e., RMSSD; p = .028) and HRV reflective of baroreflex function (i.e., low frequency power; p = .018) while accurately performing resonant frequency breathing wit…
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Lin IM, Tai LY, Fan SY (2014)MEDLINE-indexed journal, not yet read by usInternational journal of psychophysiology : official journal of the International Organization of Psychophysiology79 citations Breathing at a rate of 5.5 breaths per minute with equal inhalation-to-exhalation ratio increases heart rate variability.
Objectives: Prior studies have found that a breathing pattern of 6 or 5.5 breaths per minute (bpm) was associated with greater heart rate variability (HRV) than that of spontaneous breathing rate. However, the effects of combining the breathing rate with the inhalation-to-exhalation ratio (I:E ratio) on HRV indices are inconsistent. This study aimed to examine the differences in HRV indices and subjective feelings of anxiety and relaxation among four different breathing patterns.
Methods: Forty-seven healthy college students were recruited for the study, and a Latin square experimental design with a counterbalance in random sequences was applied. Participants were instructed to breathe at two different breathing rates (6 and 5.5 breaths) and two different I:E ratios (5:5 and 4:6). The HRV indices as well as anxiety and relaxation levels were measured at baseline (spontaneous breathing) a…
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Heart rate variability is associated with emotion recognition: direct evidence for a relationship between the autonomic nervous system and social cognition.
It is well established that heart rate variability (HRV) plays an important role in social communication. Polyvagal theory suggests that HRV may provide a sensitive marker of one's ability to respond and recognize social cues. The aim of the present study was to directly test this hypothesis. Resting-state HRV was collected and performance on the Reading the Mind in the Eyes Test was assessed in 65 volunteers. HRV was positively associated with performance on this emotion recognition task confirming our hypothesis and these findings were retained after controlling for a variety of confounding variables known to influence HRV - sex, BMI, smoking habits, physical activity levels, depression, anxiety, and stress. Our data suggests that increased HRV may provide a novel marker of one's ability to recognize emotions in humans. Implications for understanding the biological basis of emotion rec…
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Heart rate variability (HRV) and posttraumatic stress disorder (PTSD): a pilot study.
Exposure to combat experiences is associated with increased risk of developing Post Traumatic Stress Disorder. Prolonged exposure therapy and cognitive processing therapy have garnered a significant amount of empirical support for PTSD treatment; however, they are not universally effective with some patients continuing to struggle with residual PTSD symptoms. Heart rate variability (HRV) is a measure of the autonomic nervous system functioning and reflects an individual's ability to adaptively cope with stress. A pilot study was undertaken to determine if veterans with PTSD (as measured by the Clinician-Administered PTSD Scale and the PTSD Checklist) would show significantly different HRV prior to an intervention at baseline compared to controls; specifically, to determine whether the HRV among veterans with PTSD is more depressed than that among veterans without PTSD. The study also aim…
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Autonomic correlates at rest and during evoked attention in children with attention-deficit/hyperactivity disorder and effects of methylphenidate.
Objective: The aim of this study was to assess autonomic nervous system functioning in children with attention-deficit/hyperactivity disorder (ADHD) and to examine the effects of methylphenidate and focussed attention.
Method: Children with ADHD (n = 19) were tested while they were stimulant free and during a period in which they were on stimulants. On both occasions, autonomic nervous system functioning was tested at baseline and during focussed attention. Autonomic nervous system functioning of control subjects was also tested at baseline and during focussed attention. Autonomic nervous system activity was determined by means of heart rate variability (HRV) and skin conductivity analyses. Attention was evoked by means of the BioGraph Infiniti biofeedback apparatus. HRV was determined by time domain, frequency domain and Poincaré analysis of RR interval data. Skin conductivity was deter…
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Touch attenuates infants' physiological reactivity to stress.
Animal studies demonstrate that maternal touch and contact regulate infant stress, and handling during periods of maternal deprivation attenuates the stress response. To measure the effects of touch on infant stress reactivity during simulated maternal deprivation, 53 dyads were tested in two paradigms: still-face (SF) and still-face with maternal touch (SF+T). Maternal and infant cortisol levels were sampled at baseline, reactivity, and recovery and mother's and infant's cardiac vagal tone were measured during the free play, still-face, and reunion episodes of the procedure. Cortisol reactivity was higher among infants in the SF condition and while cortisol decreased at recovery for infants in the SF+T, it further increased for those in the SF. Vagal tone showed a greater suppression when SF was not accompanied by maternal touch. Touch synchrony during free play was associated with high…
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Depression is associated with decreased blood pressure, but antidepressant use increases the risk for hypertension.
The present study compared blood pressure levels between subjects with clinical anxiety and depressive disorders with healthy controls. Cross-sectional data were obtained in a large cohort study, the Netherlands Study of Depression and Anxiety (N=2981). Participants were classified as controls (N=590) or currently or remittedly depressed or anxious subjects (N=2028), of which 1384 were not and 644 were using antidepressants. Regression analyses calculated the contributions of anxiety and depressive disorders and antidepressant use to diastolic and systolic blood pressures, after controlling for multiple covariates. Heart rate and heart rate variability measures were subsequently added to test whether effects of anxiety/depression or medication were mediated by vagal control over the heart. Higher mean diastolic blood pressure was found among the current anxious subjects (beta=0.932; P=0.…
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Heart rate variability, prefrontal neural function, and cognitive performance: the neurovisceral integration perspective on self-regulation, adaptation, and health.
Background: In the present paper, we describe a model of neurovisceral integration in which a set of neural structures involved in cognitive, affective, and autonomic regulation are related to heart rate variability (HRV) and cognitive performance.
Methods: We detail the pathways involved in the neural regulation of the cardiovascular system and provide pharmacological and neuroimaging data in support of the neural structures linking the central nervous system to HRV in humans. We review a number of studies from our group showing that individual differences in HRV are related to performance on tasks associated with executive function and prefrontal cortical activity. These studies include comparisons of executive- and nonexecutive-function tasks in healthy participants, in both threatening and nonthreatening conditions. In addition, we show that manipulating resting HRV levels is associa…
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Brain correlates of autonomic modulation: combining heart rate variability with fMRI.
The central autonomic network (CAN) has been described in animal models but has been difficult to elucidate in humans. Potential confounds include physiological noise artifacts affecting brainstem neuroimaging data, and difficulty in deriving non-invasive continuous assessments of autonomic modulation. We have developed and implemented a new method which relates cardiac-gated fMRI timeseries with continuous-time heart rate variability (HRV) to estimate central autonomic processing. As many autonomic structures of interest are in brain regions strongly affected by cardiogenic pulsatility, we chose to cardiac-gate our fMRI acquisition to increase sensitivity. Cardiac-gating introduces T1-variability, which was corrected by transforming fMRI data to a fixed TR using a previously published method [Guimaraes, A.R., Melcher, J.R., et al., 1998. Imaging subcortical auditory activity in humans. …
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Vagal tone and temperament as predictors of emotion regulation strategies in young children.
We examined indices of vagal tone and two dimensions of temperament as predictors of emotion regulation (ER) strategies among children (n = 54, ages 4-7) of mothers with a history of depression and control mothers. Children's (adaptive and maladaptive) ER strategies were observed during a delay of gratification (frustration) task in one protocol. In a separate and independent protocol, vagal tone was assessed during rest (baseline), during emotional challenge (reactivity) and post-challenge (recovery) and mothers rated their children's temperament (effortful control, negative affectivity). Lower vagal recovery and higher negative affectivity were associated with maladaptive ER responses to frustration. However, vagal tone and temperament were not associated with adaptive ER responses and maternal depression status did not affect the results. Overall, the findings are consistent with mode…
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Autonomic recovery after exercise in trained athletes: intensity and duration effects.
Purpose: To investigate the effects of training intensity and duration, through a range representative of training in endurance athletes, on acute recovery of autonomic nervous system (ANS) balance after exercise.
Methods: Nine highly trained (HT) male runners (VO2max 72 +/- 5 mL.kg.min(-1), 14 +/- 3 training hours per week) and eight trained (T) male subjects (VO2max 60 +/- 5 mL.kg.min(-1), 7 +/- 1 training hours per week) completed preliminary testing to determine ventilatory thresholds (VT1, VT2) and VO2max. HT performed four intensity-controlled training sessions: 60 min and 120 min below VT1; 60 min with 30 min between VT1 and VT2 (threshold); and 60 min above VT2 (6 x 3 min at 96% VO2max, 2 min of recovery). T also completed the interval session to compare ANS recovery between HT and T. Supine heart rate variability (HRV) was quantified at regular intervals through 4 h of recovery.…
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A pilot study of the efficacy of heart rate variability (HRV) biofeedback in patients with fibromyalgia.
Unlabelled: Fibromyalgia (FM) is a non-inflammatory rheumatologic disorder characterized by musculoskeletal pain, fatigue, depression, cognitive dysfunction and sleep disturbance. Research suggests that autonomic dysfunction may account for some of the symptomatology of FM. An open label trial of biofeedback training was conducted to manipulate suboptimal heart rate variability (HRV), a key marker of autonomic dysfunction.
Methods: Twelve women ages 18-60 with FM completed 10 weekly sessions of HRV biofeedback. They were taught to breathe at their resonant frequency (RF) and asked to practice twice daily. At sessions 1, 10 and 3-month follow-up, physiological and questionnaire data were collected.
Results: There were clinically significant decreases in depression and pain and improvement in functioning from Session 1 to a 3-month follow-up. For depression, the improvement occurred by Ses…
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The cardiovascular toll of stress.
Psychological stress elicits measurable changes in sympathetic-parasympathetic balance and the tone of the hypothalamic-pituitary-adrenal axis, which might negatively affect the cardiovascular system both acutely-by precipitating myocardial infarction, left-ventricular dysfunction, or dysrhythmia; and chronically-by accelerating the atherosclerotic process. We provide an overview of the association between stress and cardiovascular morbidity, discuss the mechanisms for this association, and address possible therapeutic implications.
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