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BACKGROUND: Non-ordinary states of consciousness induced by psychedelics can be accompanied by so-called peak experiences, characterized at the emotional level by their intensity and positive valence. These experiences are strong predictors of positive outcomes following psychedelic-assisted therapy, and it is therefore important to better understand their biology. Despite growing evidence that the autonomic nervous system (ANS) plays an important role in mediating emotional experiences, its involvement in the psychedelic experience is poorly understood. The aim of this study was to investigate to what extent changes in the relative influence of the sympathetic (SNS) and parasympathetic nervous systems (PNS) over cardiac activity may reflect the subjective experience induced by the short-acting psychedelic N,N-Dimethyltryptamine (DMT). METHODS: We derived measures of SNS and PNS activity from the electrocardiograms of 17 participants (11 males, mean age = 33.8 years, SD = 8.3) while they received either DMT or placebo. RESULTS: Results show that the joint influence of SNS and PNS (sympathovagal coactivation) over cardiac activity was positively related to participants ratings of Spiritual Experience and Insightfulness during the DMT experience, while also being related to improved well-being scores 2 weeks after the session. In addition, we found that the state of balance between the two ANS branches (sympathovagal balance) before DMT injection predicted scores of Insightfulness during the DMT experience, as well as subsequent sympathovagal coactivation. CONCLUSION: These findings demonstrate the involvement of the ANS in psychedelic-induced peak experiences and may pave the way to the development of biofeedback-based tools to enhance psychedelic therapy.

Preterm birth (PTB) remains a global health concern, impacting neonatal mortality and lifelong health consequences. Traditional methods for estimating PTB rely on electronic health records or biomedical signals, limited to short-term assessments in clinical settings. Recent studies have leveraged wearable technologies for in-home maternal health monitoring, offering continuous assessment of maternal autonomic nervous system (ANS) activity and facilitating the exploration of PTB risk. In this paper, we conduct a longitudinal study to assess the risk of PTB by examining maternal ANS activity through heart rate (HR) and heart rate variability (HRV). To achieve this, we collect long-term raw photoplethysmogram (PPG) signals from 58 pregnant women (including seven preterm cases) from gestational weeks 12-15 to three months post-delivery using smartwatches in daily life settings. We employ a PPG processing pipeline to accurately extract HR and HRV, and an autoencoder machine learning model with SHAP analysis to generate explainable abnormality scores indicative of PTB risk. Our results reveal distinctive patterns in PTB abnormality scores during the second pregnancy trimester, indicating the potential for early PTB risk estimation. Moreover, we find that HR, average of interbeat intervals (AVNN), SD1SD2 ratio, and standard deviation of interbeat intervals (SDNN) emerge as significant PTB indicators.

Somatic and sympathetic tones fluctuate together seamlessly across daily behaviors. In this issue of Cell, Zhang et al. describe populations of spinal projecting neurons in the rostral ventromedial medulla (rVMM) that harmonize somatic motor function and sympathetic activation. The coordinated regulation plays a vital role in supporting behaviors associated with various arousal states.

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

Treatment of youth concussion during the acute phase continues to evolve, and this has led to the emergence of guidelines to direct care. While symptoms after concussion typically resolve in 14-28 days, a portion (∼20%) of adolescents endorse persistent post-concussive symptoms (PPCS) beyond normal resolution. This report outlines a study implemented in response to the National Institute of Neurological Diseases and Stroke call for the development and initial clinical validation of objective biological measures to predict risk of PPCS in adolescents. We describe our plans for recruitment of a Development cohort of 11- to 17-year-old youth with concussion, and collection of autonomic, neurocognitive, biofluid, and imaging biomarkers. The most promising of these measures will then be validated in a separate Validation cohort of youth with concussion, and a final, clinically useful algorithm will be developed and disseminated. Upon completion of this study, we will have generated a battery of measures predictive of high risk for PPCS, which will allow for identification and testing of interventions to prevent PPCS in the most high-risk youth.

Using heart rate (HR) measurements to detect mental stress in naturalistic settings is hampered by the physiological impact of hemodynamic and metabolic demands. Correcting HR for these demands can help isolate fluctuations in HR associated with psychosocial stress responses, a concept termed additional heart rate (aHR). This study examined whether adding predictors for posture, activity type, and lagged movement intensity for the prolonged impact of physical activity (PA) improved aHR estimation across various manipulations of mental stress, posture, and PA in a controlled laboratory environment (n = 197). Accelerometer signals were used to obtain the movement intensity and to classify posture and activity type. Posture, activity type, and lagged movement intensity each led to a significant improvement in HR estimation, as measured by adjusted R2 and root mean squared error. However, HR was overestimated during quiet sitting. The aHR, computed as the difference between observed and predicted HR, generally underestimated observed task‐baseline reactivity but was sensitive to individual differences in reactivity to mental stressors. Between‐subject correlations of aHR with task‐baseline reactivity ranged from 0.62 to 0.93 across conditions. On a within‐subject level, the ability of aHR to differentiate between exposure to physical stress and mental stress was limited (recall = 0.32, precision = 0.31), but better than that of observed HR (recall = 0.02, precision = 0.02). Future research should explore the potential of this novel aHR estimation method in differentiating physical and mental demands on HR in daily life, and its predictive value for health outcomes. [ABSTRACT FROM AUTHOR]

Attention is one of the basic cognitive functions sensitive to high altitude, and most studies have focussed on exposure times of approximately 3 years; however, it is unclear how attention changes in migrants who have lived and worked at high altitude for nearly 20 years. We explored the dynamics of attentional networks and neurophysiological mechanisms in migrants over 3–20 years using the Attentional Network Test combined with Electrocardiograph and Electroencephalography and found a consistent quadratic correlation between exposure and executive control efficiency, P3 amplitude and heart rate variability (HRV), with a decrease followed by an increase/relative stability, with approximately 10 years being the breakpoint. However, neither linear nor quadratic trajectories were observed for the alerting and orienting network. Mediation analysis revealed that the P3 amplitude mediated the decrease and increase in executive control efficiency with exposure time depends on the breakpoint. Correlations between HRV and executive control efficiency and P3 amplitude suggest that U‐shaped changes in executive control in migrants may be related to body homeostasis maintained by the autonomic nervous system, and that P3 amplitude may serve as a neurophysiological marker of migrants' adaptation/recovery from high‐altitude exposure. [ABSTRACT FROM AUTHOR]

Autonomic symptoms may be local and general clinical manifestations of both epilepsy and migraine caused by the dysfunction of brain areas best known as the central autonomic network. Despite their prevalence, autonomic signs are often misdiagnosed and their treatment is undervalued. This review aims to describe the autonomic manifestations reported during seizures and migraineur attacks according to their presentation, focusing on the role of the central autonomic network (CAN) and on the parasympathetic outflow that often-induced cranial autonomic symptoms (CAS) during migraineur attacks. Further, our purpose is to analyze the pathophysiological meanings and whether their presence influences the prognosis and therapy of these disorders. [ABSTRACT FROM AUTHOR]

The activation of autonomic and hypothalamo-pituitary-adrenal (HPA) systems occurs interdependently with behavioral adjustments under varying environmental demands. Nevertheless, laboratory rodent studies examining the neural bases of stress responses have generally attributed increments in these systems to be monolithic, regardless of whether an active or passive coping strategy is employed. Using the shock probe defensive burying test (SPDB) to measure stress-coping features naturalistically in male and female rats, we identify a neural pathway whereby activity changes may promote distinctive response patterns of hemodynamic and HPA indices typifying active and passive coping phenotypes. Optogenetic excitation of the rostral medial prefrontal cortex (mPFC) input to the ventrolateral periaqueductal gray (vlPAG) decreased passive behavior (immobility), attenuated the glucocorticoid hormone response, but did not prevent arterial pressure and heart rate increases associated with rats' active behavioral (defensive burying) engagement during the SPDB. In contrast, inhibition of the same pathway increased behavioral immobility and attenuated hemodynamic output but did not affect glucocorticoid increases. Further analyses confirmed that hemodynamic increments occurred preferentially during active behaviors and decrements during immobility epochs, whereas pathway manipulations, regardless of the directionality of effect, weakened these correlational relationships. Finally, neuroanatomical evidence indicated that the influence of the rostral mPFC→vlPAG pathway on coping response patterns is mediated predominantly through GABAergic neurons within vlPAG. These data highlight the importance of this prefrontal→midbrain connection in organizing stress-coping responses and in coordinating bodily systems with behavioral output for adaptation to aversive experiences. [ABSTRACT FROM AUTHOR]

The human body has two main types of sweat glands: apocrine and eccrine. Eccrine glands are widely distributed across the skin, including areas with hair. While the eccrine glands on palms and soles help improve grip, those on the rest of the body primarily aid in thermoregulation. Sudomotor function, which controls sweating, is regulated by the sympathetic division of the autonomic nervous system through cholinergic and adrenergic pathways. The activation of eccrine glands involves intricate processes, including neurotransmitter binding, ion channel modulation, and voltage generation. Sudoscan technology utilizes electrochemical skin conductance (ESC) to non-invasively measure sudomotor function. This method, which has been standardized for accuracy, has established normative benchmarks and has proven reliable across diverse populations. Sudoscan's diagnostic performance is comparable to invasive methods such as intraepidermal nerve fiber density testing, making it a valuable tool for diagnosing small fiber neuropathy. Moreover, it has been shown to correlate with corneal nerve fiber length, providing insights into various neuropathic conditions. Compared to traditional sudomotor function tests, Sudoscan proves superior in terms of its accessibility, simplicity, and reliability, with the potential to replace or complement existing diagnostic methods. It is important to differentiate ESC, as measured by Sudoscan, from other skin conductance measures, such as galvanic skin response (GSR) or electrodermal activity (EDA). Although these methods share a common physiological principle, ESC is specifically designed for diagnosing sudomotor function, unlike GSR/EDA, which is typically used for continuous monitoring. Sudoscan's success has led to its integration into consumer health devices, such as the BodyScan from Withings, showcasing its versatility beyond clinical settings. Future research may explore ESC applications in diverse medical fields, leveraging real-world data from integrated consumer devices. Collaborative efforts between researchers and engineers promise to offer new insights into sudomotor function and its implications for broader health monitoring. This study provides a comprehensive overview of ESC, including topics such as eccrine gland physiology, sudomotor function, Sudoscan technology, normative benchmarks, diagnostic comparisons, and potential future applications. [ABSTRACT FROM AUTHOR]

Summary: Postural balance requires the interplay between several physiological signals. Indirect evidence suggests that the perception of signals arising from the autonomic nervous system might play a role (e.g. cardiac awareness). Here, we tested this hypothesis by investigating the relationship between postural control and cardiac awareness (i.e. interoception) in a sample of N = 70 healthy individuals. Postural control was measured using a medical robotic device, while cardiac awareness was evaluated using the heartbeat counting task. A within-subject design included two platform configurations (static, unstable) and two visual feedback conditions (eyes open, eyes closed). For each condition, we measured the sway area and the range of oscillation of the platform, as well as the range of oscillation and the quantity of movement of participants' trunk. In the "platform unstable, eyes closed" condition, participants with higher cardiac awareness demonstrated a significantly smaller sway area and reduced oscillations of both the platform and their trunk. These findings hint at a potential link between interoception and postural control, suggesting that the perception of internal body signals might sustain balance. [ABSTRACT FROM AUTHOR]

Key points We examined the interactive influence of hypoxia and exercise, and hypercapnia and exercise, on regional cerebral perfusion and sympathetic activation. Twenty healthy young adults (seven women) completed study trials including (1) rest in normoxia (SpO2${{S}_{{\mathrm{p}}{{{\mathrm{O}}}_{\mathrm{2}}}}}$: ∼96%, PETCO2${{P}_{{\mathrm{ETC}}{{{\mathrm{O}}}_{\mathrm{2}}}}}$: ∼36 mmHg), normocapnic hypoxia (SpO2${{S}_{{\mathrm{p}}{{{\mathrm{O}}}_{\mathrm{2}}}}}$: ∼84%, PETCO2${{P}_{{\mathrm{ETC}}{{{\mathrm{O}}}_{\mathrm{2}}}}}$: ∼36 mmHg), and normoxic hypercapnia (SpO2${{S}_{{\mathrm{p}}{{{\mathrm{O}}}_{\mathrm{2}}}}}$: ∼98%, PETCO2${{P}_{{\mathrm{ETC}}{{{\mathrm{O}}}_{\mathrm{2}}}}}$: ∼46 mmHg) and (2) unilateral rhythmic handgrip exercise (45% of maximal voluntary contraction at 1 Hz for 3 min) under the same gas conditions. Based on the exercising arm, blood flow in the contralateral internal carotid (ICABF) and ipsilateral vertebral (VABF) arteries, anterior and posterior cerebral O2 delivery (CDO2${\mathrm{C}}{{{\mathrm{D}}}_{{{{\mathrm{O}}}_{\mathrm{2}}}}}$), and muscle sympathetic nerve activity (MSNA) were measured in each trial. During exercise in hypoxia, ICABF, VABF, anterior and posterior CDO2${\mathrm{C}}{{{\mathrm{D}}}_{{{{\mathrm{O}}}_{\mathrm{2}}}}}$ were significantly lower, whereas total MSNA was significantly greater, than the sum of the responses evoked by either hypoxia or exercise alone. During exercise in hypercapnia, ICABF and anterior CDO2${\mathrm{C}}{{{\mathrm{D}}}_{{{{\mathrm{O}}}_{\mathrm{2}}}}}$ were significantly greater, whereas MSNA was lower, than the sum of the responses evoked by either hypercapnia or exercise alone. The VABF and posterior CDO2${\mathrm{C}}{{{\mathrm{D}}}_{{{{\mathrm{O}}}_{\mathrm{2}}}}}$ responses to hypercapnic exercise were not different from the summated responses. These findings suggest that the brain is hypoperfused and sympathetic outflow potentiated during hypoxic exercise, and that the brain is hyperperfused and sympathetic discharge constrained during hypercapnic exercise. The contrasting consequences for cerebral perfusion and sympathetic activation indicate a potential involvement of Cushing's mechanism in the autonomic control during exercise in healthy humans. Brain O2‐demand and ‐supply are mismatched, and muscle sympathetic nerve activity (MSNA) is enhanced in humans exercising at high altitude; the link between the two phenomena remains elusive. We evaluated the isolated and interactive effects of exercise, hypoxia, and hypercapnia on blood flow in the internal carotid (ICABF) and vertebral (VABF) arteries, and MSNA. The interaction of hypoxia and exercise was hypo‐additive for ICABF and VABF and anterior and posterior cerebral O2 delivery (CDO2${\mathrm{C}}{{{\mathrm{D}}}_{{{{\mathrm{O}}}_{\mathrm{2}}}}}$), but hyper‐additive for MSNA. The interaction of hypercapnia and exercise was hyper‐additive for ICABF and anterior CDO2${\mathrm{C}}{{{\mathrm{D}}}_{{{{\mathrm{O}}}_{\mathrm{2}}}}}$, additive for VABF and posterior CDO2${\mathrm{C}}{{{\mathrm{D}}}_{{{{\mathrm{O}}}_{\mathrm{2}}}}}$, and hypo‐additive for MSNA. These observations indicate that a suboptimal brain perfusion during hypoxic exercise coincides with a potentiated sympathetic outflow, while a (supra‐)optimal brain perfusion during hypercapnic exercise coincides with a suppressed sympathetic outflow. Our findings suggest that Cushing's mechanism may play a role in the autonomic control in exercising humans. [ABSTRACT FROM AUTHOR]

Background: Resting heart rate (HR) and HR variability (HRV) are widely used parameters to assess cardiac autonomic nervous system function noninvasively. While resting assessments can be performed during sleep or after awakening, it would be relevant to know how interchangeable the results of these measurements are. This study aimed at examining the alignment between nocturnal and morning assessments during regular endurance training and in response to intensive training. A total of 24 recreational runners performed a 3-week baseline period (BL) and a 2-week overload (OL) period (Lucia's training impulse + 80%). Their running performance was assessed with a 3000-m running test after the BL and OL. The participants recorded daily their nocturnal HR and HRV (the natural logarithm of the root mean square of successive differences; LnRMSSD) with a photoplethysmography-based wrist device and performed an orthostatic test (2-min supine, 2-min standing) every morning with a chest-strap HR sensor. The HR and LnRMSSD segments that were analyzed from the nocturnal recordings included start value (SleepStart), end value (SleepEnd), first 4-h segment 30 min after detected sleep onset (Sleep4h), and full sleep time (SleepFull). The morning segments consisted of the last-minute average in both body positions. All segments were compared at BL and in response to the 3000-m test and OL. Results: All nocturnal HR and LnRMSSD segments correlated with supine and standing segments at BL (r = 0.42 to 0.91, p < 0.05). After the 3000-m test, the HR increased and LnRMSSD decreased only in the SleepStart, Sleep4h, and SleepFull segments (p < 0.05). In response to the OL, the standing HR decreased (p < 0.01), while the LnRMSSD increased (p < 0.05) in all segments except for SleepStart. The Pearson correlations between relative changes in nocturnal and morning segments were − 0.11 to 0.72 (3000-m) and − 0.25 to 0.79 (OL). The OL response in Sleep4h HR and LnRMSSD correlated with the relative change in 3000-m time (r = 0.63, p = 0.001 and r=-0.50, p = 0.013, respectively). Conclusions: Nocturnal and morning HR and LnRMSSD correlated moderately or highly in the majority of cases during the BL, but their responses to intensive training were not similarly aligned, especially in LnRMSSD. The nocturnal segments seemed to be sensitive to physical loading, and their responses were associated with the performance-related training responses. Key Points: • Moderate-to-high correlations were found between nocturnal and morning assessments of HR and HRV during regular endurance training in recreational runners. • In their responses to maximum exercise, nocturnal and morning HR and HRV were not necessarily aligned, as nocturnal segments seemed more responsive to such a stimulus. • While lower HR and higher HRV were associated with better endurance performance in all recording segments, changes in these parameters after the overload period correlated only in nocturnal segments. [ABSTRACT FROM AUTHOR]

Introduction: Vagal nerve stimulation (VNS) is used as an alternative treatment in drug-resistant epilepsy patients. Effects of VNS on the cardiac autonomic system are controversial. In this study, we aimed to investigate the relationship between VNS parameters and heart rate variability (HRV) in epilepsy patients who underwent VNS treatment. Methods: Our study included 31 patients who underwent VNS for drug-resistant epilepsy. Patients were divided into groups according to response to VNS and VNS parameters. All patients underwent 24-h Holter ECG. Results: The mean age of 31 VNS-treated epilepsy patients included in the study was 33.87 ± 7.6 years. When patients were grouped according to VNS response, 25 patients were in the VNS responder group and six patients were in the VNS-nonresponder group. When comparing Holter parameters in the VNS responder and non-responder groups, the median HF was significantly lower in the VNS responder group. VNS duration and signal frequency had a positive effect on LF/HF, while output and off time had a negative effect on LF/HF. When ROC analysis was performed to determine the cut-off values of the parameters for the VNS-responsive state, the AUC value of the HF parameter was 0.780, which was statistically significant. The cut-off value to distinguish response to VNS was 156.9. Conclusion: In conclusion, the effects of VNS parameters on HRV parameters are quite complex. However, the conclusion is that VNS is a neuromodulation method that affects the autonomic system in a complex way. Different levels of VNS parameters may also contribute to this effect. Furthermore, HRV parameters can be used as biomarkers to predict the patient population that may benefit from VNS. [ABSTRACT FROM AUTHOR]

Sport‐related concussion (SRC) is associated with cardiovascular autonomic nervous system (ANS) dysfunction. This study examines resting cardiovascular ANS activity in adolescents with SRC compared to controls early post‐injury and after clinical recovery, analyzing its correlation with symptom severity and recovery outcomes. Cardiovascular ANS function was evaluated using heart rate variability (HRV), systolic blood pressure variability (SBPV) and baroreflex sensitivity (BRS). Symptoms were assessed via the Post‐Concussion Symptom Scale, and recovery outcomes were categorized by recovery duration. Following acute SRC, no significant differences in HRV, SBPV or BRS were found between SRC and control groups, nor between those with delayed or normal recovery. Post‐recovery, SRC participants had higher low frequency (LF) SBPV than controls and their initial assessment. When concussed participants were symptomatic, LF SBPV correlated directly with overall, cognitive, and fatigue symptom severity, while high frequency (HF) HRV inversely correlated with affective symptoms (Spearman's rho: 0.4–0.6). Resting cardiovascular ANS function remains unchanged in adolescent athletes acutely after SRC, suggesting it has limited diagnostic and prognostic potential. Although some correlations between individual symptom domains and ANS activity were observed, they were not significantly different from asymptomatic controls, limiting the ability to interpret these findings. [ABSTRACT FROM AUTHOR]

The COVID-19 pandemic has brought significant attention to the respiratory system, with much focus on lung-related disorders. However, the diaphragm, a crucial component of respiratory physiology, has not been adequately studied, especially in the context of long COVID. This review explores the multipotential role of the diaphragm in both respiratory health and disease, emphasizing its involvement in long-term complications following SARS-CoV-2 infection. The diaphragm's fundamental role in respiratory physiology and its impact on balance and posture control, breathing patterns, and autonomic nervous system regulation are discussed. This review examines complications arising from COVID-19, highlighting the diaphragm's involvement in neurological, musculoskeletal, and inflammatory responses. Particular attention is given to the neuroinvasive impact of SARS-CoV-2, the inflammatory response, and the direct viral effects on the diaphragm. The diaphragm's role in long COVID is explored, with a focus on specific symptoms such as voice disorders, pelvic floor dysfunction, and sleep disturbances. Diagnostic challenges, current methods for assessing diaphragmatic dysfunction, and the complexities of differentiating it from other conditions are also explored. This article is the first to comprehensively address diaphragmatic dysfunction resulting from COVID-19 and long COVID across various physiological and pathological aspects, offering a new perspective on its diagnosis and treatment within a multisystem context. [ABSTRACT FROM AUTHOR]

Background: The modulation of the autonomic nervous system's activity, particularly increasing its parasympathetic tone, is of significant interest in clinical physiotherapy due to its potential benefits for stress-related conditions and recovery processes. This study evaluated the effectiveness of the addition of neurodynamics in enhancing parasympathetic activation in subjects with chronic stress. Methods: A clinical trial randomly assigned participants to a group with neurodynamics (6 bpm breathing protocol + manual therapy + neurodynamic technique) or a group without neurodynamics (6 bpm breathing protocol + manual therapy only). Metrics of heart rate variability (HRV), including the Mean Heart Rate (Mean HR), standard deviation of intervals between consecutive heartbeats (SDNN), Heart Rate Difference (Diff. HR), Root Mean Square of Successive Differences (RMSSD), number of intervals differing by more than 50 ms (NN50), percentage of consecutive NN intervals that differed by more than 50 ms (pNN50), and the high-frequency component measured in standardized units (HF), were assessed before, during, and after the intervention. Results: During the intervention, the group with neurodynamics showed significant changes in all variables except in the pNN50 and HF while the group without neurodynamics only showed improvements in the Mean HR, SDNN, and RMSSD. In the post-intervention phase, the group with neurodynamics maintained an increase in HRV while the group without neurodynamics experienced a decrease, suggesting an increase in sympathetic activity. Conclusions: Vagal nerve neurodynamics appear to represent an effective method for enhancing parasympathetic activation in patients with chronic stress. The results highlight the importance of a more comprehensive analysis of HRV variables in order to obtain a correct picture of the impact of interventions on the complex and multifaceted functioning of the autonomic nervous system. [ABSTRACT FROM AUTHOR]

Wearables with photoplethysmography (PPG) sensors are being increasingly used in clinical research as a non-invasive, inexpensive method for remote monitoring of physiological health. Ensuring the accuracy and reliability of PPG-derived measurements is critical, as inaccuracies can impact research findings and clinical decisions. This paper systematically compares heart rate (HR) and heart rate variability (HRV) measures from PPG against an electrocardiogram (ECG) monitor in free-living settings. Two devices with PPG and one device with an ECG sensor were worn by 25 healthy volunteers for 10 days. PPG-derived HR and HRV showed reasonable accuracy and reliability, particularly during sleep, with mean absolute error < 1 beat for HR and 6–15 ms for HRV. The relative error of HRV estimated from PPG varied with activity type and was higher than during the resting state by 14–51%. The accuracy of HR/HRV was impacted by the proportion of usable data, body posture, and epoch length. The multi-scale peak and trough detection algorithm demonstrated superior performance in detecting beats from PPG signals, with an F1 score of 89% during sleep. The study demonstrates the trade-offs of utilizing PPG measurements for remote monitoring in daily life and identifies optimal use conditions by recommending enhancements. [ABSTRACT FROM AUTHOR]

This study aimed to investigate the effects of high-intensity running on the autonomic nervous system and sleep quality of male long-distance runners and to examine the impact of wearing magnetic garments on these parameters. Fifteen highly trained male collegiate long-distance runners participated in a randomized, double-blind crossover study. Participants completed two 30 km runs (30k-RUN) during a 10-day training camp. After each run, they wore either magnetic (MAG) or non-magnetic control (CTRL) garments. Sleep quality and heart rate variability (HRV) were assessed using a wrist-worn device before and after each 30k-RUN. Wearing MAG garments post-30k-RUN resulted in significantly longer deep sleep duration compared to CTRL. HRV analysis revealed that the MAG condition led to a significantly higher root mean square of successive RR interval differences and high-frequency power, indicating enhanced parasympathetic activity. The low-frequency to high-frequency ratio was significantly lower in MAG than in CTRL. Perceived recovery scores were significantly higher in MAG than in CTRL. The findings of this study suggest that wearing magnetic garments following high-intensity endurance running may promote parasympathetic dominance and improve sleep quality in male long-distance runners. These findings indicate that magnetic garments may be a practical method for enhancing recovery in athletes following intense training. [ABSTRACT FROM AUTHOR]

White adipose tissue (WAT) and the gut are involved in the development of neuroinflammation when an organism detects any kind of injury, thereby triggering metainflammation. In fact, the autonomous nervous system innervates both tissues, although the complex role played by the integrated sympathetic, parasympathetic, and enteric nervous system functions have not been fully elucidated. Our aims were to investigate the participation of inflamed WAT and the gut in neuroinflammation. Firstly, we conducted an analysis into how inflamed peripheral WAT plays a key role in the triggering of metainflammation. Indeed, this included the impact of the development of local insulin resistance and its metabolic consequences, a serious hypothalamic dysfunction that promotes neurodegeneration. Then, we analyzed the gut–brain axis dysfunction involved in neuroinflammation by examining cell interactions, soluble factors, the sensing of microbes, and the role of dysbiosis-related mechanisms (intestinal microbiota and mucosal barriers) affecting brain functions. Finally, we targeted the physiological crosstalk between cells of the brain–WAT–gut axis that restores normal tissue homeostasis after injury. We concluded the following: because any injury can result not only in overall insulin resistance and dysbiosis, which in turn can impact upon the brain, but that a high-risk of the development of neuroinflammation-induced neurodegenerative disorder can also be triggered. Thus, it is imperative to avoid early metainflammation by applying appropriate preventive (e.g., lifestyle and diet) or pharmacological treatments to cope with allostasis and thus promote health homeostasis. [ABSTRACT FROM AUTHOR]

The main genetic risk factors for Parkinson's disease (PD) are presently represented by variants in GBA1 gene encoding for the β‐glucocerebrosidase (GCase). Searching for a peripheral biomarker that can be used for selecting and monitoring patients in clinical trials targeting GBA1‐associated PD (GBA1‐PD) is a current challenge. We previously demonstrated that α‐synuclein oligomers expressed as proximity ligation assay (PLA) score in synaptic terminals of skin biopsy are a reliable biomarker for distinguishing idiopathic PD (iPD) from healthy controls (HC). This cross‐sectional study investigates an unexplored cohort of GBA1‐PD (n = 27) compared to 28 HC, and 36 iPD cases to (i) analyze α‐synuclein oligomers and quantify them throughout PLA score, (ii) investigate GCase expression in brain and synaptic terminals targeting the sweat gland, (iii) unravel indicators that could differentiate patients with specific GBA1 mutations. PLA score discriminates GBA1‐PD from HC with sensitivity = 88.9% (95% CI 70.84–97.65), specificity = 88.5% (95% CI 69.85–97.55), and PPV = 88.9% (95% CI 73.24–95.90), AUC value = 0.927 (95% CI 0.859–0.996). No difference was found between GBA1‐PD patients and iPD, suggesting a common pathological pathway based on α‐synuclein oligomers. GCase score did not differ in GBA1‐PD, iPD, and HC in the synaptic terminals, whereas a positive correlation was found between PLA score and GCase score. Moreover, a significant increase in synaptic density was observed in GBA1‐PD compared to iPD and HC (P < 0.0001). Employing ROC curve to discriminate GBA1‐PD from iPD, we found an AUC value for synaptic density = 0.855 (95% CI 0.749–0.961) with sensitivity = 85.2% (95% CI 66.27%–95.81%), specificity = 77.1% (95% CI 59.86%–89.58%), and PPV = 74.19% (60.53%–84.35%). The highest synaptic density values were observed in p.N409S patients. This work points out to the value of both PLA score and synaptic density in distinguishing GBA1‐PD from iPD and to their potential to stratify and monitor patients in the context of new pathway‐specific therapeutic options. [ABSTRACT FROM AUTHOR]

Background: Wearable technology is increasingly used in clinical practice and research to monitor functional gastrointestinal symptoms and mental health. Aims: This article explores the potential of wearable sensors to enhance the understanding of the autonomic nervous system (ANS), particularly its role in linking psychological and gastrointestinal function. The ANS, facilitates brain‐gut communication and is responsive to psychosocial conditions. It is implicated in disorders related to psychological stress and gut‐brain interaction. Wearable technology enables tracking of the ANS in daily life, offering complementary and alternative methods from traditional lab‐based measures. This review places focus on autonomic metrics such as respiratory sinus arrhythmia, vagal efficiency, and electrodermal activity as well as self‐reports of autonomic symptoms. Discussion: Potential applications include use of wearable sensors for tracking autonomic activity in disorder of gut‐brain interaction such as cyclic vomiting syndrome, in which ANS dysregulation may be triggered by psychosocial factors. Considerations for data interpretation and contextualization are addressed, acknowledging challenges such as situational confounders of ANS activity and accuracy of wearable devices. [ABSTRACT FROM AUTHOR]

Narratives are effective tools for evoking emotions, and physiological measurements provide a means of objectively assessing emotional reactions – making them a potentially powerful pair of tools for studying emotional processes. However, extent research combining emotional narratives and physiological measurement varies widely in design and application, making it challenging to identify previous work, consolidate findings, and design effective experiments. Our scoping review explores the use of auditory emotional narratives and physiological measures in research, examining paradigms, study populations, and represented emotions. Following the PRISMA‐ScR Checklist, we searched five databases for peer‐reviewed experimental studies that used spoken narratives to induce emotion and reported autonomic physiological measures. Among 3466 titles screened and 653 articles reviewed, 110 studies were included. Our exploration revealed a variety of applications and experimental paradigms; emotional narratives paired with physiological measures have been used to study diverse topics and populations, including neurotypical and clinical groups. Although incomparable designs and sometimes contradictory results precluded general recommendations as regards which physiological measures to use when designing new studies, as a whole, the body of work suggests that these tools can be valuable to study emotions. Our review offers an overview of research employing narratives and physiological measures for emotion study, and highlights weaknesses in reporting practices and gaps in our knowledge concerning the robustness and specificity of physiological measures as indices of emotion. We discuss study design considerations and transparent reporting, to facilitate future using emotional narratives and physiological measures in studying emotions. This scoping review offers a comprehensive resource for researchers navigating the diverse landscape of studying emotions through spoken narratives and physiological measurements. Focused on autonomic nervous system responses, it summarizes design choices, and explores applications studying a wide range of emotions and populations. This work aims to inspire further development of narratives as research tools while enhancing reporting and reproducibility in these interdisciplinary areas. [ABSTRACT FROM AUTHOR]

The article discusses the parallels between politicians and performers, focusing on their shared experiences of the limelight and performance anxiety. Topics include the relationship between physical stress responses and decision-making under pressure, how voice teachers can help students manage performance anxiety, and the role of stress conditioning in preparing for high-pressure situations.

Lipofuscin is a complex mixture of highly oxidized, cross-linked macromolecules that accumulates in neurons with age and some neurodegenerative diseases. Equine dysautonomia (ED) is a polyneuropathy that mainly affects autonomic and enteric nervous systems, resulting in alimentary tract dysfunction. Our main aim was to determine whether neuronal lipofuscin increased with increasing duration of ED. We investigated the prevalence of lipofuscin in cranial cervical ganglia of horses with acute (AED), subacute (SED), and chronic ED (CED), young controls (of similar age to ED cases), and aged controls (n = 8 per group). We used Schmorl stain for histologic detection of lipofuscin and assessed its accumulation in neurons using image analysis software. The percentage of neurons positive for lipofuscin increased with age in individual groups and all groups combined (p < 0.001). There were fewer positive neurons in AED and SED compared to aged controls (p < 0.001) and more in CED than AED cases (p = 0.042) and young controls (p = 0.012). We found a strong positive correlation between percentage positive neurons and percentage positive area of the neuron containing lipofuscin for combined groups (p < 0.001). Although neuronal lipofuscin increased in cranial cervical ganglion in CED cases, it remains to be determined whether this is a cause or consequence of neuronal degeneration. [ABSTRACT FROM AUTHOR]

• Median heart rate is significantly lower in COVID-19 related ARDS (C-ARDS). • Heart rate variability is severely impaired in C-ARDS and non-related ARDS (NC-ARDS). • HRV analysis might suggest a sympathovagal imbalance with vagal overtone in C-ARDS. Bradycardia and dysautonomia observed during SARS-Cov2 infection suggests involvement of the autonomic nervous system (ANS). Limited data exists on ANS dysregulation and its association with outcomes in patients with acute respiratory distress syndrome (ARDS) related to COVID-19 (C-ARDS) or other etiologies (NC-ARDS). We aimed to explore sympathovagal balance, assessed by heart rate variability (HRV), and its clinical prognostic value in C-ARDS compared with NC-ARDS. A single-center, prospective case-control study was conducted. Consecutive patients meeting ARDS criteria between 2020 and 2022 were included. HRV was assessed using 1-hour electrographic tracing during a stable, daytime period. Twenty-four patients with C-ARDS and 19 with NC-ARDS were included. Age, sex and ARDS severity were similar between groups. The median heart rate was markedly lower in the C-ARDS group than in the NC-ARDS group (60 [53–72] versus 101 [91–112] bpm, p <.001). Most of HRV parameters were significantly increased in patients with C-ARDS. HRV correlated with heart rate only in patients with C-ARDS. A positive correlation was found between the low-to high-frequency ratio (LF/HF) and length of intensive care unit stay (r = 0.576, p <.001). This study confirmed that C-ARDS was associated with marked bradycardia and severe ANS impairment, suggesting a sympathovagal imbalance with vagal overtone. Poor outcomes appeared to be more related to sympathetic rather than parasympathetic hyperactivation. [ABSTRACT FROM AUTHOR]

Background: Heart rate (HR) is a critical biomarker that provides insights into overall health, stress levels, and the autonomic nervous system. Pulse wave signals contain valuable information about the cardiovascular system and heart status. However, signal acquisition in wearables poses challenges, particularly when using electrical sensors, due to factors like the distance from the heart, body movement, and suboptimal electrode placement. Methods: Electrical bioimpedance (EBI) measurements using bipolar and tetrapolar electrode systems were employed for pulse wave signal acquisition from the wrist in both perpendicular and distal configurations. Signal preprocessing techniques, including baseline removal via Hankel matrix methods, normalization, cross-correlation, and peak detection, were applied to improve signal quality. This study describes the combination of sensor-level signal acquisition and processing for accurate wearable HR estimation. Results: The bipolar system was shown to produce larger Δ Z (t) , while the tetrapolar system demonstrated higher sensitivity. Distal placement of the electrodes yielded greater Δ Z (t) (up to 0.231 Ω) when targeting both wrist arteries. Bandpass filtering resulted in a better signal-to-noise ratio (SNR), achieving 3.6 dB for the best bipolar setup and 4.8 dB for the tetrapolar setup, compared to 2.6 and 3.3 dB SNR, respectively, with the Savitzky–Golay filter. The custom HR estimation algorithm presented in this paper demonstrated improved accuracy over a reference method, achieving an average error of 1.8 beats per minute for the best bipolar setup, with a mean absolute percentage error (MAPE) of 8%. Conclusions: The analysis supports the feasibility of using bipolar electrode setups on the wrist and highlights the importance of electrode positioning relative to the arteries. The proposed signal processing method, featuring a preprocessing pipeline and HR estimation algorithm, provides a proof-of-concept demonstration for HR estimation from EBI signals acquired at the wrist. [ABSTRACT FROM AUTHOR]

Triple A syndrome (TAS), also known as Allgrove syndrome (OMIM#231550), is a rare, autosomal recessive disorder characterized by the triad of alacrima, achalasia, and adrenal insufficiency. Additional neurological features may be present in two-thirds of patients, involving central, peripheral, and autonomic nervous system manifestations. TAS is caused by genetic alterations in the AAAS gene on chromosome 12q13, which encodes the nuclear pore complex protein termed ALADIN (ALacrima, Achalasia, aDrenal Insufficiency, and Neurologic disorder). ALADIN plays a crucial role in nucleocytoplasmic transport of specific proteins, including the transport of DNA repair proteins. TAS exhibits significant phenotypic variability in terms of symptom onset, frequency, and severity, often presenting with a progressive clinical course indicative of an underlying degenerative process. In this study, we report the case of an infant with exceptionally early and severe manifestations of triple A syndrome, with a review of the literature. Our patient exhibited the complete classical triad of TAS at six months of age, being among the youngest reported cases of the syndrome. The clinical course was complicated by severe involvement of the autonomic nervous system, neurogenic bladder, and recurrent urinary tract infections. Subsequently, the patient developed acute pancreatitis, leading to multiorgan dysfunction and a fatal outcome at 25 months of age. This case underscores the potential for atypical disease presentations and the need for clinical awareness in diagnosing and managing patients with TAS. [ABSTRACT FROM AUTHOR]

Objective: Chocolate is a popular food that may affect the activity of the autonomic nervous system (ANS). The aim of this study was to determine the effect of a single dose of dark or milk chocolate on ANS cardiac control during rest and mental stress induced by the Stroop test (ST). Methods: Healthy participants, divided into DARK or MILK chocolate groups, ingested corresponding type of chocolate (1 g/kg body weight). They underwent measurement of ANS during relaxation and ST before and 2 h after chocolate consumption. ANS control was assessed by determination of heart rate (HR) and heart rate variability using parameters related to complex autonomic modulation (TP, SDNN) or primary vagal modulation (HFnu, RMSSD). Results: HR was always increased during ST in both groups. Relaxation HR values after chocolate ingestion were higher only in the DARK chocolate group. During ST, values of TP, SDNN and HFnu decreased before and after chocolate ingestion in the DARK group, but only before chocolate ingestion in the MILK group. RMSSD values decreased during ST before and after chocolate ingestion in both groups. Relaxation TP, RMSSD and HFnu values after chocolate ingestion were lower in the DARK but not in the MILK group. Conclusion: The results suggest that even a single dose of milk chocolate attenuates changes in ANS cardiac control induced by mental stress, whereas a single dose of dark chocolate has an activating effect on the heart via modification of ANS cardiac control at rest. Different levels of sugars and cocoa biologically active compounds in the two types of chocolate could explain the observed effects. [ABSTRACT FROM AUTHOR]

This study investigates predictors of unsatisfactory outcomes in female overactive bladder (OAB) patients treated with oral monotherapy by analyzing skin sympathetic nerve activity (SKNA) using a novel "neuECG" method. The study included 55 newly diagnosed female patients with idiopathic OAB, autonomic function was evaluated using neuECG before treatment initiation, and validated OAB questionnaires and urodynamic studies were administered. Initial monotherapy was administered for the first 4 weeks, with non‐responders defined as patients not achieving satisfactory symptom relief and requiring further treatment. Responders (n = 32) and non‐responders (n = 23) had no significant differences in baseline characteristics or urodynamic parameters; however, non‐responders exhibited significantly higher baseline average SKNA (aSKNA) (1.36 ± 0.49 vs. 0.97 ± 0.29 μV, p = 0.001), higher recovery aSKNA (1.28 ± 0.46 vs. 0.97 ± 0.35 μV, p = 0.007), and a lower stress/baseline ratio of aSKNA (1.05 ± 0.42 vs. 1.26 ± 0.26, p = 0.029). Baseline aSKNA had the highest predictive value for monotherapy refractoriness in OAB (AUROC = 0.759, p = 0.001), with an optimal cut‐off point of >1.032 μV. These findings suggest that elevated pre‐treatment aSKNA can predict resistance to oral monotherapy in OAB, warranting close monitoring and proactive treatment strategies for patients with high aSKNA. [ABSTRACT FROM AUTHOR]

BACKGROUND: Excessive fear, worry and behavioral disturbances define anxiety, with particular significance attributed to vagal nerve, a crucial transmitter of information to the brain regions governing anxiety. Highlighting the importance of vagal nerve, transcutaneous auricular vagal nerve stimulation (TaVNS) emerges as a tolerable and safe technique. The success of non-invasive vagal nerve stimulation in alleviating anxiety underscores the pivotal role of the vagal nerve. OBJECTIVES: The purpose of this study was to assess the effectiveness of physiotherapy interventions in mitigating anxiety among retired teachers during the COVID-19 pandemic, emphasizing the relevance of targeting the vagal nerve for improved mental well-being. METHODS: 60 retired teachers diagnosed with anxiety were chosen through random allocation. Participants were divided into two groups: Group A (Experimental group) received transcutaneous auricular vagal nerve stimulation (TaVNS), and Group B (Control group) underwent the Jacobson relaxation technique. Intervention period spanned 4 weeks, with four sessions per week, lasting 30 minutes. The outcome measures included Generalized Anxiety Disorder-7 (GAD-7) questionnaire and salivary cortisol levels. RESULTS: Following the 4-week intervention, both groups exhibited a significant reduction in Generalized Anxiety Disorder-7 (GAD-7) scores and salivary cortisol levels (P < 0.001). Notably, Group A demonstrated a significantly higher effectiveness rate compared to Group B. CONCLUSION: The study concludes that transcutaneous auricular vagal nerve stimulation (TaVNS) is effective in reducing anxiety among retired teachers. Transcutaneous auricular vagal nerve stimulation (TaVNS) proves to be a powerful and effective intervention in alleviating anxiety among retired teachers, emphasizing its potential significance in enhancing mental well-being. [ABSTRACT FROM AUTHOR]

The article "Serotonin and schizophrenia: what influences what?" explores the relationship between serotonin and schizophrenia, highlighting the role of the serotonergic system in the pathogenesis of schizophrenia. The text discusses the complex nature of schizophrenia, its symptoms, and the impact of genetic and environmental factors on its development. It also delves into the molecular mechanisms linking serotonin to schizophrenia and the bidirectional influence between the two. The article emphasizes the importance of understanding early molecular events to unravel the etiology of schizophrenia and develop interventions to modulate these processes. [Extracted from the article]

Postural orthostatic tachycardia syndrome (POTS) presents excessive orthostatic tachycardia and orthostatic intolerance. POTS is a common and therapeutically challenging condition affecting numerous people worldwide. As many disease entities can be confused with POTS, it becomes critical to identify this syndrome. Moreover, unbalanced autonomic nervous activity can induce cardiovascular diseases and influence the bio-feedback mechanism: Baroreflex (BR) and cerebral autoregulation (CA). BR and CA are important bio-mechanisms that maintain a stable circulatory system via the autonomic nervous system. Therefore, an impaired autonomic nervous system would lead to imbalanced BRS and CA. Consequently, we propose an advanced cross-correlation function (ACCF) time-domain approach to analyze baroreflex and cerebral autoregulation using physiological signals. This study assesses relation changes in BR and CA using ACCF in POTS for early clinical detection and diagnosis. The ACCF analysis results has thresholds that reveal that the BR of healthy and POTS groups present significantly different maximum CCF values (p < 0.05). The complete CCF index shows that the BR phase changes significantly into phase lag in the POTS group. Although CA analysis using the maximum CCF index was mildly weak, it did not differ in the POTS group. Thus, POTS only affects BR. An increasing sympathetic activity might induce an unbalanced baroreflex effect and increase cerebral vasomotor tone with CA. Maximum CCF value correlation coefficients between BR and CA indicated positive in POTS groups and negative in the healthy group. It could be speculated that the sympathetic nervous system compensates to improve BR function, which remains CA function. The advantage of this ACCF algorithm is that it helps observe BR and CA for early detection. [ABSTRACT FROM AUTHOR]

Hepatic lipid metabolism is regulated by the autonomic nervous system of the liver, with the sympathetic innervation being extensively studied, while the parasympathetic efferent innervation is less understood despite its potential importance. In this study, we investigate the consequences of disrupted brain–liver communication on hepatic lipid metabolism in mice exposed to obesogenic conditions. We found that a subset of hepatocytes and cholangiocytes are innervated by parasympathetic nerve terminals originating from the dorsal motor nucleus of the vagus. The elimination of the brain–liver axis by deleting parasympathetic cholinergic neurons innervating the liver prevents hepatic steatosis and promotes browning of inguinal white adipose tissue (ingWAT). The loss of liver-innervating cholinergic neurons increases hepatic Cyp7b1 expression and fasting serum bile acid levels. Furthermore, knockdown of the G protein-coupled bile acid receptor 1 gene in ingWAT reverses the beneficial effects of the loss of liver-innervating cholinergic neurons, leading to the reappearance of hepatic steatosis. Deleting liver-innervating cholinergic neurons has a small but significant effect on body weight, which is accompanied by an increase in energy expenditure. Taken together, these data suggest that targeting the parasympathetic cholinergic innervation of the liver is a potential therapeutic approach for enhancing hepatic lipid metabolism in obesity and diabetes. The liver autonomic nervous system is regulated by hepatic lipid metabolism. This study shows that a subset of hepatocytes and cholagiocytes are innervated by nerve terminals originating from the dorsal motor nucleus of the vagus nerve in high-fat diet fed mice and ablation of these cholinergic neurons could prevent hepatic steatosis. [ABSTRACT FROM AUTHOR]

Background: Trigeminal neurostimulation of the dorsal anterior mucosal surface of the tongue has been proposed to treat a variety of pathologies and to promote neuro-muscular coordination and rehabilitation. Dental ULFTENS can also be considered a form of trigeminal neurostimulation applied to the skin surface bilaterally at the level of the tragus. It has been used for years in dentistry for practical and diagnostic purposes. Previous work has combined the two stimulation techniques showing an efficacy in improving HRV in healthy young women of dental ULFTENS applied to the mucosal surface of the tongue. This work sought to assess whether there is a difference in HRV in relation to the site of application of dental ULFTENS (tragus vs. tongue). If effective in reducing the activity of arousal circuits, this tongue-level stimulation technique could have new clinical applications. Material and method: A new intraoral device allowed electrical stimulation of the dorsal anterior mucosa of the tongue in 80 healthy young women divided into two groups: TUD group (ULFTENS stimulation on the mucosa of the tongue) and Tragus group (stimulation with ULFTENS bilaterally in the area of the tragus). The effects on HRV were monitored by photoplethysmographic wave (PPG). The HRV parameters studied were RMSSD, HF, LF, LF/HF. Results: Only the TUD group showed a significant change in selected HRV parameters that was maintained even in the epoch after the end of electrical stimulation. This effect can be considered as a vagal activation and an increased of HRV parameter. The Tragus group did not show significant change in the direction of increased HRV but showed an opposite trend. There were no undesirable or annoying effects of stimulation. Conclusion: Stimulation of the dorsal anterior (trigeminal) mucosal surface of the tongue with ULFTENS applied with an intraoral device was shown to be able to increase HRV while the same stimulation on tragus area, according to traditional dental ULFTENS procedure, did not show the same effects. Clinical implications: This stimulation technique could be an aid in the diagnosis and treatment of disorders characterized by autonomic disequilibrium such as, in the dental field, TMDs. Trial registration: "Effects of Trigeminal Neurostimulation on Heart Rate Variability: Comparing Tragus and Tongue Stimulation". ID number: NCT06549205. Date of first registration: August 1st 2024. https://clinicaltrials.gov/study/NCT06549205?id=%09NCT06549205&rank=1. [ABSTRACT FROM AUTHOR]

Background: The autonomic nervous system (ANS) is affected by several factors, including major nutrients. However, their effects on the ANS remains unclear. Most studies had several limitations. They focused on humans, therefore they had difficulties excluding factors other than the nutrients. Their observation periods were too short (<4 hours) to align with typical absorption times of carbohydrates versus fats. They assessed the effects compared with the pre-prandial state rather than comparisons between different nutrient types. Objective: We aimed to investigate the effects of carbohydrates and fats on the ANS. Method: We employed a rat model to exclude the effects of external stimuli, used sufficient observation period, and compared the ANS parameters among animals fed 3 different diets. The rats were divided into carbohydrate-rich-diet (carb group) and fat-rich-diet (fat group) groups. We investigated the effects of carbohydrates and fats on the ANS by measuring heart rate variability parameters in rats. Electrodes and electrocardiography (ECG) transmitters were implanted in 14 Wistar rats maintained on a standard diet for 2 days followed by the experimental diets for 2 days. ECG readings were continuously recorded for 4 days. The R waves, function of the R-R interval, and time were calculated. A fast Fourier transform was used to obtain the power spectrum of the fluctuation (low frequency [LF: 0.2-0.75 Hz]; high frequency [HF: 0.75-3.0 Hz]; LF/HF ratio). Result: Compared with the standard-diet group, the carb group showed significantly increased HF activity, while the fat group showed a significantly increased LF/HF ratio. Conclusion: The results reveal a link between macronutrients and ANS activity. [ABSTRACT FROM AUTHOR]

Although heart rate variability (HRV) is a valid method to evaluate the behavior of the autonomic nervous system in individuals with temporomandibular disorder (TMD), the measurement can easily be biased by factors involving the analysis methodology, such as the removal of artifacts. Therefore, the objective of this investigation is to evaluate the impact of using different levels of threshold-based artifact correction to process HRV data in individuals with TMD. This cross-sectional observational study. Adults aged 18 to 55 years old with a diagnosis of myogenic TMD, score ≥ 50 on the Fonseca Anamnestic Index (FAI) and pain ≥ 3 on the Numerical Pain Scale (NPS) participated. The HRV was registered in the supine position (short-term) using a Polar S810i. Kubios software was used for HRV analysis using all filters. One-way ANOVA with Tukey-Kramer post-hoc was used to test the differences in HRV using the different Kubios Software artifact correction filters. The effect size was calculated based on the Cohen d. The very strong filter was statistically different (p < 0.05) compared to the no filter in all overview and time domain variables. In the frequency domain, the variables VLF, LF, HF and Total Power showed statistical differences (p < 0.05) when using the very strong filter. The same occurred with the variables SD1, SD2 and DFA α2 of the non-linear analysis (p < 0.05). The most restrictive filter of the Kubios software (very strong) significantly impacts the quantification of HRV parameters in individuals with TMD. [ABSTRACT FROM AUTHOR]

The Raphe Pallidus (RPa) is a brainstem nucleus containing sympathetic premotor neurons that control thermogenesis and modulate cardiovascular function. It receives inputs from various hypothalamic areas, including the Lateral Hypothalamus (LH), a heterogeneous region intricately involved in several autonomic and behavioral functions. A key subpopulation of neurons in the LH expresses orexin/hypocretin, a neuropeptide which is crucially involved in the regulation of the wake-sleep states and feeding behavior. The RPa receives orexinergic projections from the LH and orexinergic signalling in the RPa has been shown to enhance thermogenesis in the anaesthetized rat, but only in the presence of an already existing thermogenic drive, without significantly affecting cardiovascular function. The present work was aimed at exploring the effects on thermoregulation and autonomic function and the possible role in the modulation of the wake-sleep states and feeding behavior of orexin injection in the RPa in the free-behaving rat. In order to assess the influence of an already present thermogenic drive on orexinergic signalling in the RPa, animals were studied at three different ambient temperatures (Ta, 10°C, 24°C, and 32°C). We found that orexin injection into the RPa variably affected the wake-sleep states, autonomic functions, motor activity, and feeding behavior, at the different Tas. In particular, in the first post-injection hour, we observed an increase in wakefulness, which was large at Ta 24°C and Ta 10°C and rather mild at Ta 32°C. Deep brain temperature was increased by orexin injection at Ta 10°C, but not at either Ta 24°C or Ta 32°C. Moreover, an increase in mean arterial blood pressure occurred at Ta 24°C, which was probably masked by the high baseline levels at Ta 10°C and was completely absent at Ta 32°C. Finally, an enhancement in feeding behavior was observed at Ta 24°C and 10°C only. In accordance with what observed in anaesthetized rats, orexinergic signalling in the RPa seems to be ineffective in the absence of any thermogenic drive. Moreover, the effects observed on the wake-sleep states and feeding behavior introduce the RPa as a novel player in the central neural network promoting wakefulness and feeding. [ABSTRACT FROM AUTHOR]

Periodic limb movements in sleep (PLMS) are a prevalent disorder characterized by rhythmic, involuntary movements of the lower limbs, such as dorsiflexion of the ankle and extension of the big toe, occurring in periodic intervals during sleep. These movements are often linked to disrupted autonomic nervous system (ANS) activity and altered interoception. Interoception involves perceiving internal bodily states, like heartbeat, breathing, hunger, and temperature, and plays a crucial role in maintaining homeostasis and the mind–body connection. This review explores the complex relationships between PLMS, heart rate variability (HRV), ANS dysregulation, and their impact on psychiatric disorders. By synthesizing the existing literature, it provides insights into how ANS dysregulation and altered interoceptive processes, alongside PLMS, contribute to psychiatric conditions. The review highlights the potential for integrated diagnostic and therapeutic approaches and presents a cause-and-effect model illustrating the mutual influence of psychiatric disorders, ANS dysregulation, PLMS, and interoception. [ABSTRACT FROM AUTHOR]

The document explores the complexities of brain development and the key molecules and pathology involved in the process. It highlights the stages of neuron generation, differentiation, migration, axon guidance, synapse formation, and neural network establishment. Factors such as genetics, environment, lifestyle, and chemical influences play crucial roles in brain development from prenatal stages to adulthood. The document emphasizes the importance of proper nutrition, stimulation, and healthy lifestyle habits for optimal brain development, impacting future learning abilities and overall health. [Extracted from the article]

Emotional neglect (EN), characterized by a lack of emotional attunement in childhood, leads to deficits in emotion regulation, increase in self-criticism, and poor mental health outcomes including depression, anxiety, and substance use disorders. Treatment for adults that experienced childhood emotional neglect is necessary, but not sufficiently studied. Self-criticism can be treated with Compassion Focused Therapy (CFT), but the impacts of EN require additional focus on regulating the autonomic nervous system. This practice advance utilizes trauma-informed care and polyvagal theory to augment CFT using a four-pronged approach. This includes the role of the therapist and the therapeutic relationship, assessment and identification of EN, client psychoeducation on the influence of EN on the mind and body, and integration of self-regulation and self-compassion activities. This multi-modal intervention can reduce the debilitating effects of EN for individuals, their loved ones, and the behavioral health systems that support them. [ABSTRACT FROM AUTHOR]

Key points The autonomic nervous system (ANS) and pain exhibit a reciprocal relationship, where acute pain triggers ANS responses, whereas resting ANS activity can influence pain perception. Nociceptive signalling can also be altered by ‘top‐down’ processes occurring in the brain, brainstem and spinal cord, known as ‘descending modulation’. By employing the conditioned pain modulation (CPM) paradigm, we previously revealed a connection between reduced low‐frequency heart rate variability and CPM. Individuals with chronic pain often experience both ANS dysregulation and impaired CPM. Baroreceptors, which contribute to blood pressure and heart rate variability regulation, may play a significant role in this relationship, although their involvement in pain perception and their functioning in chronic pain have not been sufficiently explored. In the present study, we combined artificial ‘baroreceptor stimulation’ in both pressure pain and CPM paradigms, seeking to explore the role of baroreceptors in pain perception and descending modulation. In total, 22 individuals with chronic low back pain (CLBP) and 29 individuals with no‐pain (NP) took part in the present study. We identified a differential modulation of baroreceptor stimulation on pressure pain between the groups of NP and CLBP participants. Specifically, NP participants perceived less pain in response to baroreflex activation, whereas CLBP participants exhibited increased pain sensitivity. CPM scores were associated with baseline measures of baroreflex sensitivity in both CLBP and NP participants. Our data support the importance of the baroreflex in chronic pain and a possible mechanism of dysregulation involving the interaction between the ANS and descending pain modulation. Baroreflex stimulation has different effects on pressure pain in participants with chronic pain compared to matched individuals with no‐pain. Baroreceptor activation decreases pain in participants with no‐pain but increases pain perception in participants with chronic pain. Baroreflex sensitivity is associated with conditioned pain modulation in both groups of chronic pain and no‐pain participants. The reactivity of the baroreflex during autonomic stress demonstrated a positive correlation with Pain Trait scores in participants with chronic back pain. [ABSTRACT FROM AUTHOR]

The malfunctioning of cardiac autonomic control in epileptic patients develops ventricular tachyarrhythmia and causes sudden unexpected death in epilepsy patients (SUDEP). Various clinical studies investigated the effect of epilepsy on cardiac autonomic control by performing heart rate variability (HRV) analysis; however, results are unclear regarding whether sympathetic, parasympathetic, or both branches of the autonomic nervous system (ANS) are affected in epilepsy and also the impact of anticonvulsant treatment on the ANS. This study follows the systematic protocols to investigate epilepsy and its anticonvulsant treatment on cardiac autonomic control by using linear and nonlinear HRV analysis measures. The electronic databases of PubMed, Embase, and Cochrane Library were used for the collection of studies. Initially, 1475 articles were identified whereas after 2-staged exclusion criteria, 33 studies were selected for execution of the review process and meta-analysis. For meta-analysis, four comparisons were performed (epilepsy patients): (1) controls (healthy subject with no history of epilepsy) versus untreated patients; (2) treated (patients under treatment that have a seizure) versus untreated patients; (3) controls versus treated patients; and (4) refractory versus well-controlled (epilepsy patients that were seizure-free for last 1 year). For treated and untreated patients, there was no significant difference whereas well-controlled patients presented higher values as compared to refractory patients. Meta-analysis was performed for the time-domain, frequency-domain, and nonlinear parameters. Untreated patients in comparison with controls presented significantly lower HF (high-frequency) and LF (low-frequency) values. These LF (g = − 0.9; 95% CI − 1.48 to − 0.37) and HF (g = − 0.69; 95% confidence interval (CI) − 1.24 to − 0.16) values were affirming suppressed both, vagal and sympathetic activity, respectively. Additionally, LF and HF value was increased in most of the studies indicating suppressed vagal tone, while for some studies, their value decreased to indicate suppressed sympathetic activity. No significant difference was observed for the remaining comparisons. Results affirmed the hypothesis that suppressed sympathetic activity affects sympathovagal balance and leads to SUDEP, as the LF value was significantly lower for patients as compared to healthy subjects. The overall effect size and statistical results for LF and HF were significant, showing the research and clinical significance of our study. [ABSTRACT FROM AUTHOR]

This is a cross-sectional study which examines the influence on heart rate variability (HRV) indices in premenopausal women and post-menopausal women and also its correlation with menopausal symptoms. Menopause is characterized by various physiological changes that occur in the reproductive organs and other systems of the body. One change that occurs in the cardiovascular system is modulation of autonomic activity. Menopause causes an imbalance of the autonomic nervous control of the cardiovascular system that shifts toward sympathetic hyperactivity. Material and methods: The study involved 140 women who were divided into two groups, 70 premenopausal women of age group 40-55 years and 70 postmenopausal women of age group 40-55 years. Heart rate variability indices were observed in both groups. Result: The various heart rate variability parameters like SDRR, RMSSD, pRR50, VLF and HF in post-menopausal women was decreased compared to pre-menopausal women. LF and LF/HF ratio in post-menopausal women was increased compared to premenopausal women. Also, LF and LF/HF ratio in symptomatic post-menopausal women was increased compared to asymptomatic post-menopausal women. Conclusion: The present study concludes that, menopause shifts the autonomic sympathovagal balance towards sympathetic predominance in post-menopausal women. [ABSTRACT FROM AUTHOR]

The impact of music on the human body has been extensively chronicled in ancient texts, particularly in the Indian Vedas. However, contemporary medical literature lacks sufficient empirical evidence to substantiate these claims. This paper aims to succinctly present key aspects that can offer a more profound comprehension of how music can be integrated into present-day medical practices, ultimately facilitating enhanced mental, physical, and spiritual well-being. [ABSTRACT FROM AUTHOR]

Background: Medical students frequently adopt poor postures such as slouching potentially impacting health. Heart rate variability (HRV) serves as an indicator of autonomic nervous system function, correlated with cardiovascular health. Aims and Objectives: The objective of the study was to compare HRV parameters among medical students in three postures: Sitting erect, easy pose (cross-legged), and slouching (stooping head and shoulders). Materials and Methods: A comparative cross-sectional study enrolled 26 male medical students. Participants were instructed to maintain each posture for 5 min while HRV was recorded using a Polar V800. Time domain and frequency domain parameters among different postures were analyzed using Friedman's test and post hoc tests for pairwise comparisons. P<0.05 was considered significant. Data were expressed as median interquartile range. Results: Significant differences were observed in HRV parameters between postures. The easy pose demonstrated a significantly higher median value of root mean square of differences of successive RR intervals (48.28 ms vs. 35.35 ms) and pNN50% (24.40% vs. 13.62%) compared to slouching. Frequency domain analysis revealed a significantly higher median value of high-frequency (HF) power in easy pose (626.56 ms² vs. 378.15 ms²) and HF normalized unit (33.78 vs. 22.55) compared to slouching. A lower low frequency (LF)/HF ratio and (1.96 vs. 3.43) lower LF normalized unit (66.18 vs. 77.30) was also seen in easy pose. Although statistically not significant, the parasympathetic indicators of HRV were higher in erect sitting compared to slouching posture. Conclusion: Among medical students, adopting the easy pose (cross-legged sitting) appeared to enhance HRV and thus increase parasympathetic activity, whereas adopting slouching postures decreased it. [ABSTRACT FROM AUTHOR]

Cerebral palsy (CP) is a group of movement disorders that impair posture and mobility, often leading to spasticity and joint contractures. Interventions like serial casting are commonly used to improve joint mobility and manage spasticity in children with CP. However, its effects on the autonomic nervous system (ANS) remain unclear. This study aimed to evaluate the effects of serial casting and ankle–foot orthoses (AFOs) on ANS responses during a virtual reality (VR) standing task, comparing these interventions with a barefoot condition. Thirty children with CP were randomized into three groups (n = 10 per group): serial casting, AFOs, and barefoot. Heart rate variability (HRV) was used to assess ANS responses across three phases: seated rest, VR task, and recovery. The results showed that the serial casting group exhibited higher sympathetic activity during rest compared to the other groups, but had a reduced sympathetic response during the VR task. Additionally, the serial casting group displayed a more pronounced parasympathetic rebound during recovery, similar to the orthoses and barefoot groups. While serial casting provides essential joint stability, it alters ANS response patterns, leading to heightened sympathetic activation at rest, without providing significant improvements in ANS behavior during physical activity. [ABSTRACT FROM AUTHOR]