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The identification of reliable biomarkers of transcutaneous auricular vagus nerve stimulation (taVNS) responsiveness is a key challenge both at the clinical and preclinical level. Vagally-mediated heart rate variability (vmHRV), a surrogate measure of cardiac vagal efferent activity, is an ideal candidate. Yet, the effects of taVNS on vmHRV remain inconclusive, likely due to the high degree of heterogeneity in stimulation protocols (e.g., taVNS parameters and side of the ear target), and little consideration of contributing factors such as sex differences. This study investigates sex differences in heart rate and vmHRV responses to different protocols of taVNS in adult rats. Male and female wild-type Groningen rats received sham or active stimulation (6 Hz or 20 Hz, 1 ms, 6 V) on the left or right auricular concha region. ECG signals were recorded before (10 min), during (20 min) and after (10 min) each session in a between-subject design. We found differential side-, frequency- and sex-specific chronotropic responses to taVNS, whereby heart rate decreased and vmHRV indexes increased at 6 Hz in males and at 20 Hz in females. Also, increases in vmHRV were only observed for right-side taVNS. The current findings suggest that biological sex should be considered for fine-tuning regulation of taVNS-induced cardiac responses and provide information regarding the side-specific effects of taVNS on vmHRV. These results will likely guide future rodent research to the choice of the most appropriate stimulation protocol in both sexes for generating information that can be translated into taVNS-related strategies in humans., Competing Interests: Declaration of competing interest Nothing to declare., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

In humans, sex disparities exist in the prevalence of social stress-related disorders, yet our understanding of the predisposing factors and underlying mechanisms is still elusive. Also at the preclinical level, the investigation of sex differences in social stress responses is limited. In this study, adult male and female wild-type Groningen rats were repeatedly exposed to witness social defeat stress (WS) to assess sex-specific behavioral, neuroendocrine, and cardiac responses to the same social stress paradigm. Male and female rats bore witness to an aggressive social defeat episode between two males for nine consecutive days or were exposed to a control (CTR) procedure. Stress-related parameters were assessed in correspondence to the first and last WS/CTR exposure and also during subsequent exposure to the stress context alone in the absence of social defeat. During WS, rats of both sexes displayed larger amounts of burying behavior and smaller amounts of rearing and grooming behaviors, but with a greater extent in female witnesses. Cardiac autonomic responses to WS were similar between the sexes, yet only females displayed higher plasma corticosterone levels after the first WS exposure compared to CTRs, and had a larger corticosterone increase than male witnesses upon repeated WS. Exposure to the stress context alone (i.e., without the presence of the aggressive resident rat) elicited greater amount of burying behavior and more pronounced and persistent tachycardic responses in females than males with a history of WS. Our findings suggest sex-disparities in the response of adult rats to WS at multiple behavioral, cardiac, and neuroendocrine levels, highlighting the utility of this social stress paradigm for investigating predisposing factors and pathophysiological mechanisms underlying sex-specific vulnerabilities to stress-related pathologies., Competing Interests: Declaration of competing interest The authors state no conflict of interest., (Copyright © 2024 The Author(s). Published by Elsevier Inc. All rights reserved.)

Driver Monitoring Systems (DMSs) play a key role in preventing hazardous events (e.g., road accidents) by providing prompt assistance when anomalies are detected while driving. Different factors, such as traffic and road conditions, might alter the psycho-physiological status of a driver by increasing stress and workload levels. This motivates the development of advanced monitoring architectures taking into account psycho-physiological aspects. In this work, we propose a novel in-vehicle Internet of Things (IoT)-oriented monitoring system to assess the stress status of the driver. In detail, the system leverages heterogeneous components and techniques to collect driver (and, possibly, vehicle) data, aiming at estimating the driver's arousal level, i.e., their psycho-physiological response to driving tasks. In particular, a wearable sensorized bodice and a thermal camera are employed to extract physiological parameters of interest (namely, the heart rate and skin temperature of the subject), which are processed and analyzed with innovative algorithms. Finally, experimental results are obtained both in simulated and real driving scenarios, demonstrating the adaptability and efficacy of the proposed system.

The link between neuroticism and the various indicators of daily cortisol fluctuations is frequently noted to be inconsistent or lacking in strength. The current study aimed to investigate the predictive capacity of both self-assessment and external evaluations of neuroticism, along with their interaction, on multiple indices of diurnal cortisol variations. This research involved the assessment of neuroticism using self-report and external evaluations among 166 working individuals, coupled with the collection of saliva samples over two consecutive workdays. Employing multilevel response surface analysis, our findings indicated that self-reported neuroticism exhibited a stronger association with cortisol indices compared to external evaluations. Additionally, the level of alignment between self-assessment and external ratings of neuroticism specifically impacted the prediction of estimates of daily cortisol production. We discuss the theoretical and practical implications of these results., Competing Interests: Declaration of competing interest Authors have no conflict of interest to declare., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

Stressors can initiate a cascade of central and peripheral changes that modulate mesocorticolimbic dopaminergic circuits and, ultimately, behavioral response to rewards. Driven by the absence of conclusive evidence on this topic and the Research Domain Criteria framework, random-effects meta-analyses were adopted to quantify the effects of acute stressors on reward responsiveness, valuation, and learning in rodent and human subjects. In rodents, acute stress reduced reward responsiveness ( g  = -1.43) and valuation ( g  = -0.32), while amplifying reward learning ( g  = 1.17). In humans, acute stress had marginal effects on valuation ( g  = 0.25), without affecting responsiveness and learning. Moderation analyses suggest that acute stress neither has unitary effects on reward processing in rodents nor in humans and that the duration of the stressor and specificity of reward experience (i.e., food vs drugs) may produce qualitatively and quantitatively different behavioral endpoints. Subgroup analyses failed to reduce heterogeneity, which, together with the presence of publication bias, pose caution on the conclusions that can be drawn and point to the need of guidelines for the conduction of future studies in the field., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2024 The Authors.)

Pharmacological inhibition of fatty acid amide hydrolase (FAAH) activity has antidepressant-like effects in preclinical models of stress. In this study, we investigated whether the antidepressant-like effects of FAAH inhibition are associated with corresponding changes in gut microbial and lipidomic profiles, which are emerging as critical components in the pathophysiology of depression. Adult male Wistar rats experienced five weeks of repeated social defeat or control procedure and were treated with the FAAH inhibitor URB694 (0.3 mg/kg/day, i.p.) or vehicle starting from the third week. Repeated social defeat induced the emergence of depressive-like behavioral (sucrose preference reduction and passive coping behaviors in the forced swim test) and neuroendocrine (increased corticosterone levels) changes, which were prevented by URB694 treatment. Repeated social defeat also provoked a significant variation in gut microbiota (changes in the relative abundance of 14 bacterial taxa) and lipidic (e.g., glycerophospholipids) composition. These stress-induced changes were prevented by URB694 treatment. These findings indicate that inhibition of FAAH activity with URB694 blocks the co-occurrence of depressive-like behavioral and neuroendocrine changes and alterations in gut microbial and lipid composition in rats exposed to repeated social defeat. In conclusion, these results suggest that the gut microbiota-lipid crosstalk may represent a novel biological target for FAAH inhibitors to enhance stress resilience., Competing Interests: Declaration of competing interest None., (Copyright © 2024 The Author(s). Published by Elsevier Inc. All rights reserved.)

In a complex social environment, stimuli from different sensory modalities need to be integrated to decode communicative meanings. From very early in life, infants have to combine a multitude of sensory features with social and affective attributes. Of all senses, touch constitutes a privileged channel to carry affective-motivational meanings and foster social connection. In the present study, we investigate whether sharing sensory stimulation that varies for its affective value differentially affects infants' attention towards visual stimuli. 6 to 11-month-old infants (N = 42) were familiarized with two characters respectively matched with tactile (affective or non-affective) and auditory stimulation; then repeatedly exposed to scenes where the two characters moved towards target objects. Our results showed a main effect of stimulation (sound vs. touch) on looking times during familiarization, with longer looking times when sound is provided. During scenes presentation, a main effect of the type of touch (affective vs. non affective) emerged, with longer looking times in infants that previously experienced affective touch, suggesting that this sensory experience may critically engage the self and modulate infant attention. Overall, these findings suggest that while sound acts as attention getter, affective touch supports sustained attention towards complex visual scenes beyond the stimulation period itself., (© 2024 The Authors. Infancy published by Wiley Periodicals LLC on behalf of International Congress of Infant Studies.)

Introduction: Interpersonal motor synchrony (IMS) is the spontaneous, voluntary, or instructed coordination of movements between interacting partners. Throughout the life cycle, it shapes social exchanges and interplays with intra- and inter-individual characteristics that may diverge in Autism Spectrum Disorder (ASD). Here we perform a systematic review and meta-analysis to summarize the extant literature and quantify the evidence about reduced IMS in dyads including at least one participant with a diagnosis of ASD., Methods: Empirical evidence from sixteen experimental studies was systematically reviewed, encompassing spontaneous and instructed paradigms as well as a paucity of measures used to assess IMS. Of these, thirteen studies (n = 512 dyads) contributed measures of IMS with an in situ neurotypical partner (TD) for ASD and control groups, which could be used for meta-analyses., Results: Reduced synchronization in ASD-TD dyads emerged from both the systematic review and meta-analyses, although both small and large effect sizes (i.e., Hedge's g) in favor of the control group are consistent with the data (Hedge's g = .85, p < 0.001, 95% CI[.35, 1.35], 95% PI[-.89, 2.60])., Discussion: Uncertainty is discussed relative to the type of task, measures, and age range considered in each study. We further discuss that sharing similar experiences of the world might help to synchronize with one another. Future studies should not only assess whether reduced IMS is consistently observed in ASD-TD dyads and how this shapes social exchanges, but also explore whether and how ASD-ASD dyads synchronize during interpersonal exchanges., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Carnevali, Valori, Mason, Altoè and Farroni.)

Bifidobacteria are commensal microorganisms that typically inhabit the mammalian gut, including that of humans. As they may be vertically transmitted, they commonly colonize the human intestine from the very first day following birth and may persist until adulthood and old age, although generally at a reduced relative abundance and prevalence compared to infancy. The ability of bifidobacteria to persist in the human intestinal environment has been attributed to genes involved in adhesion to epithelial cells and the encoding of complex carbohydrate-degrading enzymes. Recently, a putative mucin-degrading glycosyl hydrolase belonging to the GH136 family and encoded by the perB gene has been implicated in gut persistence of certain bifidobacterial strains. In the current study, to better characterize the function of this gene, a comparative genomic analysis was performed, revealing the presence of perB homologues in just eight bifidobacterial species known to colonize the human gut, including Bifidobacterium bifidum and Bifidobacterium longum subsp. longum strains, or in non-human primates. Mucin-mediated growth and adhesion to human intestinal cells, in addition to a rodent model colonization assay, were performed using B. bifidum PRL2010 as a perB prototype and its isogenic perB-insertion mutant. These results demonstrate that perB inactivation reduces the ability of B. bifidum PRL2010 to grow on and adhere to mucin, as well as to persist in the rodent gut niche. These results corroborate the notion that the perB gene is one of the genetic determinants involved in the persistence of B. bifidum PRL2010 in the human gut., (© 2024 The Authors. Microbial Biotechnology published by Applied Microbiology International and John Wiley & Sons Ltd.)

Rationale: Exposure to traumatic events can lead to alterations in social and anxiety-related behaviors. Emerging evidence suggests that peripheral host-defense processes are implicated in the expression of stress-induced behavioral responses and may be targeted to mitigate the negative sequalae of stress exposure., Objectives: In this study, we used the peripherally restricted FAAH inhibitor URB937 to investigate the effects of the fatty acyl ethanolamide (FAE) family of lipid mediators - which include the endocannabinoid anandamide and the endogenous PPAR-α agonists, oleoylethanolamide and palmitoylethanolamide - on behavioral and peripheral biochemical responses to two ethologically distinct rat models of stress., Methods: Male adult rats were exposed to acute social defeat, a model of psychological stress (Experiment 1), or to the predator odor 2,5-dihydro-2,4,5-trimethylthiazoline (TMT), a test of innate predator-evoked fear (Experiment 2), and subsequently treated with URB937 (1 or 3 mg/kg, intraperitoneal) or vehicle. Behavioral analyses were conducted 24 h (Experiment 1) or 7 days (Experiment 2) after exposure., Results: URB937 administration prevented the emergence of both social avoidance behavior after social defeat stress and anxiety-related behaviors after TMT exposure. Further, URB937 administration blocked social defeat-induced transient increase in plasma concentrations of pro-inflammatory cytokines and the elevation in plasma corticosterone levels observed 24 h after social defeat CONCLUSIONS: Enhancement of peripheral FAAH-regulated lipid signaling prevents the emergence of stress-induced social avoidance and anxiety-like behaviors in male rats through mechanisms that may involve an attenuation of peripheral cytokine release induced by stress exposure., (© 2023. The Author(s).)

Recognizing emotional expressions is a prerequisite for understanding others' feelings and intentions, a key component of social interactions that develops throughout childhood. In multisensory social environments, touch may be crucial for emotion processing, linking external sensory information with internal affective states. The current study investigated whether affective touch facilitates recognition of emotional expressions throughout childhood. Preschool children (N = 121 3- to 6-year-olds) were presented with different tactile stimulations followed by an emotion-matching task. Results revealed that affective touch fosters the recognition of negative emotions and increases the speed of association of positive emotions, highlighting the centrality of tactile experiences for socioemotional understanding. The current research opens new perspectives on how to support emotional recognition with potential consequences for the development of social functioning., (Copyright © 2023. Published by Elsevier Inc.)

In the present ecological study, we analyzed the relations of a set of self-efficacy beliefs at work to parameters of diurnal cortisol variation. Specifically, using data collected during two consecutive working days from 166 workers, we tested a mediation model positing social and work-related self-efficacy beliefs as mediators of the relations between self-regulatory emotional self-efficacy beliefs in managing negative emotions and cortisol indicators. Results from the multilevel mediation analyses supported the proposed model for work-related self-efficacy, which resulted as a significant mediator of the relation between self-regulatory emotional self-efficacy beliefs in managing negative emotions and the overall cortisol daily production indexed by computing the area under the curve with respect to the ground. Findings suggest the importance of self-efficacy beliefs for workers' physiological adjustment. Theoretical and practical contributions of the findings are discussed., Competing Interests: Declaration of competing interest The authors declare that they have no conflicts of interest. Research involving human participants and/or animals: The study was approved by the Sapienza University of Rome Internal Review Board and conducted in accordance with ethical standards as laid down in the 1964 Declaration of Helsinki and its later amendments or comparable ethical standards., (Copyright © 2023 The Authors. Published by Elsevier B.V. All rights reserved.)

The impact of psychosocial stressors on cardiovascular health in women is of growing interest in both the popular and scientific literature. Rodent models are useful for providing direct experimental evidence of the adverse cardiovascular consequences of psychosocial stressors, yet studies in females are scarce. Here, we investigated the effects of repeated exposure to witness social defeat stress (WS) on cardiomyocyte contractile function and intracellular Ca 2+ homeostasis in young adult wild-type Groningen female rats. Female rats bore witness to an aggressive social defeat episode between two males for nine consecutive days or were exposed to a control procedure. Stress-related behaviors were assessed during the first and last WS/control exposure. Twenty-four hours after the last exposure, plasma corticosterone levels were measured, and cardiomyocytes were isolated for analyses of contractile properties and Ca 2+ transients, and expression levels of proteins involved in intracellular Ca 2+ dynamics. The results show an impairment of the intrinsic cardiac mechanical properties and prolonged intracellular Ca 2+ decay in WS female rats showing social stress-related behavioral (larger amounts of burying behavior) and neuroendocrine (elevated plasma corticosterone levels) phenotypes. Further, the results implicate alterations in the sarcoplasmic reticulum Ca 2+ -ATPase/phospholamban complex in the contractile defects described in cardiomyocytes of WS female rats. In conclusion, this study highlights the utility of the WS model as an ethologically relevant social stressor for investigating pathophysiological processes that occur in the heart of female subjects and may increase vulnerability to social stress-related cardiovascular risk., Competing Interests: Declaration of Competing Interest The authors state no conflict of interest., (Copyright © 2023 The Author(s). Published by Elsevier Inc. All rights reserved.)

This study examines the predictive value of conflict and conflict-related variations in negative emotion dynamics, with respect to three cortisol indicators (cortisol awakening responses; overall cortisol output; diurnal cortisol slopes). A total of 166 workers provided momentary reports on conflict(s) with colleagues and negative emotions 10 times a day for 2 workdays and salivary cortisol samples 5 times a day. The results of latent growth curve piecewise multilevel models revealed that the occurrence of a conflict and the number of conflicts introduced significant variations in specific cortisol parameters indicating greater cortisol levels throughout the day. Moreover, the conflict-elicited negative emotion boost predicted a lower reduction of cortisol levels from morning to evening. Last, the postconflict decline in negative emotions was negatively associated with overall cortisol production. This study contributes to establishing a potential association between naturally occurring episodic conflicts at work and daily cortisol patterns, identifying within-person fluctuations in negative emotions as psychological mechanisms through which this occurs. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Aims: Nfix is a transcription factor belonging to the Nuclear Factor I (NFI) family comprising four members (Nfia, b, c, x). Nfix plays important roles in the development and function of several organs. In muscle development, Nfix controls the switch from embryonic to fetal myogenesis by promoting fast twitching fibres. In the adult muscle, following injury, lack of Nfix impairs regeneration, inducing higher content of slow-twitching fibres. Nfix is expressed also in the heart, but its function has been never investigated before. We studied Nfix role in this organ., Methods: Using Nfix-null and wild type (WT) mice we analyzed: (1) the expression pattern of Nfix during development by qPCR and (2) the functional alterations caused by its absence, by in vivo telemetry and in vitro patch clamp analysis., Results and Conclusions: Nfix expression start in the heart from E12.5. Adult hearts of Nfix-null mice show a hearts morphology and sarcomeric proteins expression similar to WT. However, Nfix-null animals show tachycardia that derives form an intrinsic higher beating rate of the sinus node (SAN). Molecular and functional analysis revealed that sinoatrial cells of Nfix-null mice express a significantly larger L-type calcium current (Cacna1d + Cacna1c). Interestingly, downregulation of Nfix by sh-RNA in primary cultures of neonatal rat ventricular cardiomyocytes induced a similar increase in their spontaneous beating rate and in I CaL current. In conclusion, our data provide the first demonstration of a role of Nfix that, increasing the L-type calcium current, modulates heart rate., (© 2023 The Authors. Acta Physiologica published by John Wiley & Sons Ltd on behalf of Scandinavian Physiological Society.)

The effects of excitability, refractoriness, and impulse conduction have been independently related to enhanced arrhythmias in the aged myocardium in experimental and clinical studies. However, their combined arrhythmic effects in the elderly are not yet completely understood. Hence, the aim of the present work is to relate relevant cardiac electrophysiological parameters to enhanced arrhythmia vulnerability in the in vivo senescent heart. We used multiple-lead epicardial potential mapping in control (9-month-old) and aged (24-month-old) rat hearts. Cardiac excitability and refractoriness were evaluated at numerous epicardial test sites by means of the strength-duration curve and effective refractory period, respectively. During sinus rhythm, durations of electrogram intervals and waves were prolonged in the senescent heart, compared with control, demonstrating a latency in tissue activation and recovery. During ventricular pacing, cardiac excitability, effective refractory period, and dispersion of refractoriness increased in the aged animal. This scenario was accompanied by impairment of impulse propagation. Moreover, both spontaneous and induced arrhythmias were increased in senescent cardiac tissue. Histopathological evaluation of aged heart specimens revealed connective tissue deposition and perinuclear myocytolysis in the atria, while scattered microfoci of interstitial fibrosis were mostly present in the ventricular subendocardium. This work suggests that enhanced arrhythmogenesis in the elderly is a multifactorial process due to the joint increase in excitability and dispersion of refractoriness in association with enhanced conduction inhomogeneity. The knowledge of these electrophysiological changes will possibly contribute to improved prevention of the age-associated increase in cardiac arrhythmias., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Our ability to perform voluntary actions and make choices is shaped by the motivation from control over the resulting effects (agency) and from positive outcomes (reward). The underlying action-outcome binding mechanisms rely on sensorimotor abilities that specialise through child development and undergo different trajectories in autism. The study aimed at disentangling the role of agency and reward in driving action selection of autistic and non-autistic children and adults, who were asked to freely select one of three candies and feed the animals appearing on a tablet. The candies were associated with different probabilities of delivering a neutral vs no effect (agency task), or a positive vs neutral effect (reward task). Choices and reaction times (RT) were measured to understand whether participants preferred and were faster at selecting options with higher probability of producing a neutral vs. no effect (agency) or a positive vs. neutral effect (reward). Participants' choices and RT were not affected by agency, whereas a more frequent selection of the option with higher probability of a positive vs. neutral effect emerged across groups, thus suggesting a reward effect. Autistic participants selected less frequently the option with chance level of receiving a neutral or no effect, which could be interpreted as a sign of reduced tolerance of uncertainty. Across tasks, conditions and age groups, autistic participants presented shorter RT, which is a marker of reduced action planning and control. Future research should deepen how tolerance of uncertainty, action planning and control impact the way autistic individuals make choices in everyday life situations, potentially contributing to restricted and repetitive behaviours., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2023 Valori et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

The present study aimed to investigate sex differences in measures of cardiac chronotropy and heart rate variability (HRV) in 132 young adult wild-type Groningen rats ( n = 45 females). Electrocardiographic signals were recorded for 48 h in freely moving rats to quantify heart rate (HR) and inter-beat interval (IBI) as measures of cardiac chronotropy, and time- and frequency-domain HRV parameters as physiological readouts of cardiac vagal modulation. Females showed greater vagally-mediated HRV despite having higher HR and shorter IBI than males during undisturbed conditions. Such differences were evident i) at any given level of HRV, and ii) both during the 12-h light/inactive and 12-h dark/active phase of the daily cycle. These findings replicate the paradoxical cardiac chronotropic control reported by human meta-analytic findings, since one would expect greater vagally-mediated HRV to be associated with lower HR and longer IBI. Lastly, the association between some HRV measures and HR was stronger in female than male rats. Overall, the current study in young adult rats provides data illustrating a sex-dependent association between vagally-mediated HRV and indexes of cardiac chronotropy. The current results i) are in line with human findings, ii) suggest to always consider biological sex in the analysis and interpretation of HRV data in rats, and iii) warrant the use of rats for investigating the neuro-hormonal basis and temporal evolution of the impact of sex on the association between vagally-mediated HRV and cardiac chronotropy, which could inform the human condition., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Carnevali, Barbetti, Statello, Williams, Thayer and Sgoifo.)

Background: Surgeons are exposed to high levels of intraoperative stress, which could compromise their psychological well-being in the long term. This study aimed at exploring the effects of real operations on the activity of stress response systems (i.e., cardiac autonomic function and hypothalamic-pituitary-adrenal axis) during and in the aftermath of surgery, and the moderating role of individual psychobiological characteristics and different levels of experience (senior vs expert surgeons)., Methods: Heart rate, heart rate variability, and salivary cortisol measures (as indexes of cardiac autonomic and hypothalamic-pituitary-adrenal axis activity, respectively) were assessed during real operations and in the perioperative period in a sample of surgeons (n = 16). Surgeons' psychometric characteristics were collected using questionnaires., Results: Real operations triggered both cardiac autonomic and cortisol stress responses which were independent from surgeons' level of experience. Intraoperative stress responses did not affect cardiac autonomic activity during the following night but were associated with a blunted cortisol awakening response. Moreover, senior surgeons reported higher levels of negative affectivity and depressive symptoms than expert surgeons prior to the surgery. Lastly, the magnitude of heart rate responses to surgery positively correlated with scores on negative affectivity, depression, perceived stress, and trait anxiety scales., Conclusion: This exploratory study allows to put forward the hypotheses that in surgeons cardiac autonomic and cortisol stress responses to real operations (i) may be associated with specific individual psychological characteristics regardless of the level of experience, (ii) and may have a longer lasting impact on hypothalamic-pituitary-adrenal axis function with potential implications for surgeons' physical and psychological well-being., (© 2023. The Author(s).)

This study explored the relationships between self-esteem level and self-esteem variability at work with parameters of diurnal cortisol rhythm, using intensive longitudinal data collected during two consecutive working days from N = 166 workers. Participants self-reported measures of sex, height, weight, self-esteem, neuroticism, and negative events at T0. Then, they answered a single item of self-esteem 4 times per day. Self-esteem variability was assessed by means of the relative variability index approach proposed by Mestdagh et al. (2018). Further, participants collected salivary samples at specific time points for analysis of diurnal cortisol patterns. Self-esteem average levels and a specific form of self-esteem variability were associated with diurnal cortisol parameters. In particular, results showed a relationship between low self-esteem and blunted cortisol awakening response, specifically when low self-esteem levels were stable over time. Moreover, self-esteem variability predicted a lower diurnal cortisol decline and a smaller magnitude of overall cortisol production. Present findings highlight the neuroendocrine correlates of self-esteem level and variation at work, suggesting potential pathways by which short-term variability in self-esteem states may impact hypothalamic-pituitary-adrenal axis functioning and long-term workers' health and well-being., Competing Interests: Conflict of interest The authors declare they have no conflict of interest to disclose., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Chronic social stress has been epidemiologically linked to increased risk for cardiovascular disease, yet the underlying pathophysiological mechanisms are still largely elusive. Mitochondrial (dys)function represents a potential intersection point between social stress exposure and (mal)adaptive cardiac responses. In this study, we used a rodent model of social stress to study the extent to which alterations in the cellular mechanical properties of the heart were associated with changes in indexes of mitochondrial function. Male adult rats were exposed to repeated episodes of social defeat stress or left undisturbed (controls). ECG signals were recorded during and after social defeat stress. Twenty-four hours after the last social defeat, cardiomyocytes were isolated for analyses of mechanical properties and intracellular Ca 2+ dynamics, mitochondrial respiration, and ATP content. Results indicated that social defeat stress induced potent cardiac sympathetic activation that lasted well beyond stress exposure. Moreover, cardiomyocytes of stressed rats showed poor contractile performance (e.g., slower contraction and relaxation rates) and intracellular Ca 2+ derangement (e.g., slower Ca 2+ clearing), which were associated with indexes of reduced reserve respiratory capacity and decreased ATP production. In conclusion, this study suggests that repeated social stress provokes impaired cardiomyocyte contractile performance and signs of altered mitochondrial bioenergetics in the rat heart. Future studies are needed to clarify the causal link between cardiac and mitochondrial functional remodeling under conditions of chronic social stress., Competing Interests: The authors declare no conflict of interest., (© 2022 The Authors. Published by Elsevier Ltd.)

Our ability to perform voluntary actions and make choices is shaped by the motivation from having control over the resulting effects (agency) and positive outcomes (reward). We offer an overview of distinct and common behavioral and neural signatures of agency and reward. We discuss their typical and atypical developmental trajectories, focusing on autism spectrum disorder (ASD), which is characterized by neurodiverse processes underlying action selection. We propose that reduced sensitivity to agency and reward in ASD may be related to atypical multisensory processes and motor planning, with potential for understanding restricted and repetitive behaviors. We emphasize the limitations of the existing literature, and prospects for future research. Understanding the neurocognitive processes that shape the way people with ASD select actions and perceive outcomes is essential to support not only learning, but also volition and self-determination.

Amoxicillin-clavulanic acid (AMC) is the most widely used antibiotic, being frequently prescribed to infants. Particular members of the genus Bifidobacterium are among the first microbial colonizers of the infant gut, and it has been demonstrated that they exhibit various activities beneficial for their human host, including promotion/maintenance of the human gut microbiota homeostasis. It has been shown that natural resistance of bifidobacteria to AMC is limited to a small number of strains. In the current study, we investigated the mitigation effects of AMC-resistant bifidobacteria in diversity preservation of the gut microbiota during AMC treatment. To this end, an in vitro coculture experiment based on infant fecal samples and an in vivo study employing a rodent model were performed. The results confirmed the ability of AMC-resistant bifidobacterial strains to bolster gut microbiota resilience, while specific covariance analysis revealed strain-specific and variable impacts on the microbiota composition by individual bifidobacterial taxa. IMPORTANCE The first microbial colonizers of the infant gut are members of the genus Bifidobacterium , which exhibit different activities beneficial to their host. Amoxicillin-clavulanic acid (AMC) is the most frequently prescribed antibiotic during infancy, and few strains of bifidobacteria are known to show a natural resistance to this antibiotic. In the present work, we evaluated the possible positive effects of AMC-resistant bifidobacterial strains in maintaining gut microbiota diversity during AMC exposure, performing an in vitro and in vivo experiment based on an infant gut model and a rodent model, respectively. Our results suggested the ability of AMC-resistant bifidobacterial strains to support gut microbiota restoration.

Human faces are one of the most prominent stimuli in the visual environment of young infants and convey critical information for the development of social cognition. During the COVID-19 pandemic, mask wearing has become a common practice outside the home environment. With masks covering nose and mouth regions, the facial cues available to the infant are impoverished. The impact of these changes on development is unknown but is critical to debates around mask mandates in early childhood settings. As infants grow, they increasingly interact with a broader range of familiar and unfamiliar people outside the home; in these settings, mask wearing could possibly influence social development. In order to generate hypotheses about the effects of mask wearing on infant social development, in the present work, we systematically review N  = 129 studies selected based on the most recent PRISMA guidelines providing a state-of-the-art framework of behavioral studies investigating face processing in early infancy. We focused on identifying sensitive periods during which being exposed to specific facial features or to the entire face configuration has been found to be important for the development of perceptive and socio-communicative skills. For perceptive skills, infants gradually learn to analyze the eyes or the gaze direction within the context of the entire face configuration. This contributes to identity recognition as well as emotional expression discrimination. For socio-communicative skills, direct gaze and emotional facial expressions are crucial for attention engagement while eye-gaze cuing is important for joint attention. Moreover, attention to the mouth is particularly relevant for speech learning. We discuss possible implications of the exposure to masked faces for developmental needs and functions. Providing groundwork for further research, we encourage the investigation of the consequences of mask wearing for infants' perceptive and socio-communicative development, suggesting new directions within the research field., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Carnevali, Gui, Jones and Farroni.)

Multimedia technologies and virtual reality offer unique possibilities to manipulate sensory, motor, interpersonal, and cognitive processes contributing to atypical developmental trajectories, thus holding an explosive potential to design innovative and engaging interventions. However, there has been little progress in developing interventions that go beyond the patient's diagnosis or the fascination of technology and rather spring from a deep understanding of the specific neuropsychological processes to be nurtured in individuals. This perspective paper outlines how recent insights from developmental cognitive neuroscience can be leveraged to promote children's multidimensional development and highlight future directions and challenges for innovating both research and clinical practice. Finally, we focus on some practical examples of multimedia and virtual reality activities we have designed to stimulate bodily-self experiences, which are crucial for building up a coherent sense of self and lay the foundation for interacting with the external world. Atypical bodily self is an early marker of heterogeneous neurodevelopmental conditions (such as autism spectrum disorders) and seems to be under-targeted in research and clinical approaches.

Resting heart rate variability (HRV), a surrogate index of cardiac vagal modulation, is considered a putative biomarker of stress resilience as it reflects the ability to effectively regulate emotions in a changing environment. However, most studies are cross-sectional, precluding longitudinal inferences. The high degree of uncertainty and fear at a global level that characterizes the COVID-19 pandemic offers a unique opportunity to explore the utility of HRV measures as longitudinal predictors of stress resilience. This study examined whether resting measures of HRV prior to the COVID-19 outbreak (i.e. nearly 2 years before; Time 0) could predict emotion regulation strategies and daily affect in healthy adults during the May 2020 lockdown (Time 1). Moreover, we evaluated the association between HRV measures, emotion regulation strategies, subjective perception of COVID-19 risk, and self-reported depressive symptoms at Time 1. Higher resting HRV at Time 0 predicted a stronger engagement in more functional emotion regulation strategies, as well as of higher daily feelings of safeness and reduced daily worry at Time 1. Moreover, depressive symptoms negatively correlated with HRV and positively correlated with the subjective perception of COVID-19 risk at Time 1. Current data support the view that HRV might not only be a marker but also a precursor of resilience under stressful times.

Animal studies increasingly indicate that the gut microbiota composition and function can be involved in the pathophysiology and progression of Alzheimer's disease (AD) at multiple levels. However, few studies have investigated this putative gut-brain axis in human beings, and none of them considered diet as a determinant of intestinal microbiota composition. Epidemiological studies highlight that a high intake of fruit and vegetables, such as that typical of the Mediterranean diet, can modulate AD progression. Thus, nutritional interventions are being increasingly studied as a possible non-pharmacological strategy to slow down the progression of AD. In particular, polyphenols and fibers represent the nutritional compounds with the higher potential of counterbalancing the pathophysiological mechanisms of dementia due to their antioxidant, anti-inflammatory, and anti-apoptotic properties. These actions are mediated by the gut microbiota, that can transform polyphenols and fibers into biologically active compounds including, among others, phenyl-γ-valerolactones, urolithins, butyrate, and other short-chain fatty acids. In this review, the complex mechanisms linking nutrition, gut microbiota composition, and pathophysiology of cognitive decline in AD are discussed, with a particular focus on the role of polyphenols and fibers. The gaps between pre-clinical and clinical studies are particularly emphasized, as well as the urgent need for studies comprehensively evaluating the link between nutrition, microbiome, and clinical aspects of AD.

Many factors acting during the neonatal period can affect neurological development of the infant. Neonatal seizures (NS) that frequently occur in the immature brain may influence autonomic maturation and lead to detectable cardiovascular signs. These autonomic manifestations can also have significant diagnostic and prognostic value. The analysis of Heart Rate Variability (HRV) represents the most used and feasible method to evaluate cardiac autonomic regulation. This narrative review summarizes studies investigating HRV dynamics in newborns with seizures, with the aim of highlighting the potential utility of HRV measures for seizure detection and management. While HRV analysis in critically ill newborns is influenced by many potential confounders, we suggest that it can enhance the ability to better diagnose seizures in the clinical setting. We present potential applications of the analysis of HRV, which could have a useful future role, beyond the research setting., Competing Interests: Declaration of Competing Interest None., (Copyright © 2021 Elsevier Masson SAS. All rights reserved.)

This study investigated epigenetic risk factors that may contribute to stress-related cardiac disease in a rodent model. Experiment 1 was designed to evaluate the expression of microRNA-34a (miR-34a), a known modulator of both stress responses and cardiac pathophysiology, in the heart of male adult rats exposed to a single or repeated episodes of social defeat stress. Moreover, RNA sequencing was conducted to identify transcriptomic profile changes in the heart of repeatedly stressed rats. Experiment 2 was designed to assess cardiac electromechanical changes induced by repeated social defeat stress that may predispose rats to cardiac dysfunction. Results indicated a larger cardiac miR-34a expression after repeated social defeat stress compared to a control condition. This molecular modification was associated with increased vulnerability to pharmacologically induced arrhythmias and signs of systolic left ventricular dysfunction. Gene expression analysis identified clusters of differentially expressed genes in the heart of repeatedly stressed rats that are mainly associated with morphological and functional properties of the mitochondria and may be directly regulated by miR-34a. These results suggest the presence of an association between miR-34a overexpression and signs of adverse electromechanical remodeling in the heart of rats exposed to repeated social defeat stress, and point to compromised mitochondria efficiency as a potential mediator of this link. This rat model may provide a useful tool for investigating the causal relationship between miR-34a expression, mitochondrial (dys)function, and cardiac alterations under stressful conditions, which could have important implications in the context of stress-related cardiac disease.

Understanding the association between autonomic nervous system [ANS] function and brain morphology across the lifespan provides important insights into neurovisceral mechanisms underlying health and disease. Resting-state ANS activity, indexed by measures of heart rate [HR] and its variability [HRV] has been associated with brain morphology, particularly cortical thickness [CT]. While findings have been mixed regarding the anatomical distribution and direction of the associations, these inconsistencies may be due to sex and age differences in HR/HRV and CT. Previous studies have been limited by small sample sizes, which impede the assessment of sex differences and aging effects on the association between ANS function and CT. To overcome these limitations, 20 groups worldwide contributed data collected under similar protocols of CT assessment and HR/HRV recording to be pooled in a mega-analysis (N = 1,218 (50.5% female), mean age 36.7 years (range: 12-87)). Findings suggest a decline in HRV as well as CT with increasing age. CT, particularly in the orbitofrontal cortex, explained additional variance in HRV, beyond the effects of aging. This pattern of results may suggest that the decline in HRV with increasing age is related to a decline in orbitofrontal CT. These effects were independent of sex and specific to HRV; with no significant association between CT and HR. Greater CT across the adult lifespan may be vital for the maintenance of healthy cardiac regulation via the ANS-or greater cardiac vagal activity as indirectly reflected in HRV may slow brain atrophy. Findings reveal an important association between CT and cardiac parasympathetic activity with implications for healthy aging and longevity that should be studied further in longitudinal research., (© 2020 The Authors. Psychophysiology published by Wiley Periodicals LLC on behalf of Society for Psychophysiological Research.)

Affective touch (gentle, caress-like touch) carries a rewarding meaning, which may represent a neurophysiological foundation for the development of social interactions from the earliest stages of life. Developmental studies have shown evidence of infants' sensitivity to affective touch as reflected by a decrease in heart rate and activation of the insular cortex. Moreover, affective touch has been shown to regulate infants' emotional state, reinforce eye contact and facilitate learning of facial information, suggesting that affective touch may promote social functioning from the earliest stages of development. The present study aims to investigate the role of affective touch in enhancing engagement with social stimuli, exploring sustained attention and cardiac responses to faces as signatures of the underlying psychophysiological mechanism. Four-months-old infants (N = 40) were repeatedly presented with a female face paired with touch (hand stroking vs tapping with a brush in two different blocks) alternating with a face presented without tactile stimulation (familiarization phase), followed by a visual preference test between the two faces. Our results revealed an attenuated cardiac response in the affective compared to the non-affective condition during the familiarization phase. During the test phase infants looked longer at both the faces presented in the affective touch condition, compared to the faces in the non-affective condition. These findings suggest that affective touch might promote engagement in social interactions by facilitating physiological state regulation during processing of multisensory social information., (Copyright © 2020 IBRO. Published by Elsevier Ltd. All rights reserved.)

Objective: The aim of this study was to assess age-related changes in cardiac autonomic modulation and heart rate variability (HRV) and their association with spontaneous and pharmacologically induced vulnerability to cardiac arrhythmias, to verify the translational relevance of mouse models for further in-depth evaluation of the link between autonomic changes and increased arrhythmic risk with advancing age., Methods: Heart rate (HR) and time- and frequency-domain indexes of HRV were calculated from Electrocardiogram (ECG) recordings in two groups of conscious mice of different ages (4 and 19 months old) (i) during daily undisturbed conditions, (ii) following peripheral β-adrenergic (atenolol), muscarinic (methylscopolamine), and β-adrenergic + muscarinic blockades, and (iii) following β-adrenergic (isoprenaline) stimulation. Vulnerability to arrhythmias was evaluated during daily undisturbed conditions and following β-adrenergic stimulation., Results: HRV analysis and HR responses to autonomic blockades revealed that 19-month-old mice had a lower vagal modulation of cardiac function compared with 4-month-old mice. This age-related autonomic effect was not reflected in changes in HR, since intrinsic HR was lower in 19-month-old compared with 4-month-old mice. Both time- and frequency-domain HRV indexes were reduced following muscarinic, but not β-adrenergic blockade in younger mice, and to a lesser extent in older mice, suggesting that HRV is largely modulated by vagal tone in mice. Finally, 19-month-old mice showed a larger vulnerability to both spontaneous and isoprenaline-induced arrhythmias., Conclusion: The present study combines HRV analysis and selective pharmacological autonomic blockades to document an age-related impairment in cardiac vagal modulation in mice which is consistent with the human condition. Given their short life span, mice could be further exploited as an aged model for studying the trajectory of vagal decline with advancing age using HRV measures, and the mechanisms underlying its association with proarrhythmic remodeling of the senescent heart., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Piantoni, Carnevali, Molla, Barbuti, DiFrancesco, Bucchi and Baruscotti.)

Objective: The purpose of this study was to investigate the effects of osteopathic manipulative treatment (OMT) on cardiovascular autonomic parameters after a rugby match., Methods: Resting and reactivity (ie, response to orthostasis) measures of mean arterial pressure, heart rate, and heart rate variability were assessed in 23 male players after a single session of OMT, both 18 to 20 hours after a rugby match and in a corresponding no-match condition, in a randomized, sham-controlled, crossover design., Results: Signs of reduced heart rate variability and elevated mean arterial pressure and heart rate were found 18 to 20 hours after a rugby match compared with the no-match condition. A significant increase in heart rate variability and a significant reduction in mean arterial pressure were observed after OMT in both the after-match and no-match conditions. Heart rate and heart rate variability responses to orthostasis were not affected by previous match competition, but were significantly larger after OMT compared with sham treatment., Conclusion: This study suggests the presence of cardiovascular autonomic alterations in rugby players after a competitive match, which may be indicative of prolonged fatigue and incomplete recovery. In these players, favorable changes in cardiovascular autonomic parameters were observed following a single session of OMT., (Copyright © 2021. Published by Elsevier Inc.)

The left dorsolateral prefrontal cortex (dlPFC) has been implicated in the regulation of stress-related cognitive processes and physiological responses and is the principal target of noninvasive brain stimulation techniques applied to psychiatric conditions. However, existing studies are mostly correlational and causal evidence on the role of this region in mediating specific psychophysiological mechanisms underpinning stress-related responses are needed to make the application of such techniques more efficient. To fill this gap, this study used inhibitory continuous theta burst stimulation (cTBS) in healthy individuals to examine the extent to which activity of the left dlPFC is associated with cognitive (subjective focus on a tracking task), behavioral (reaction times and variability), and physiological responses (heart rate and its variability and cortisol level) following induction of perseverative cognition. Compared to sham and left ventral PreMotor area stimulation (as active control area), inhibition of left dlPFC determined sustained autonomic and neuroendocrine activation and increased the subjective perception of being task-focused, while not changing the behavioral and self-reported stress-related responses. Adopting a causative approach, we describe a role of left dlPFC in inhibitory control of the physiological stress-response associated to perseverative thinking., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

The healthcare provider profession strongly relies on the ability to care for others' emotional experiences. To what extent burnout may relate to an actual alteration of this key professional ability has been little investigated. In an experimentally controlled setting, we investigated whether subjective experiences of global burnout or burnout depersonalization (the interpersonal component of burnout) relate to objectively measured alterations in emotion recognition and to what extent such alterations are emotion specific. Healthcare workers ( n = 90) completed the Maslach Burnout Inventory and a dynamic emotion recognition task in which faces with neutral emotional expressions gradually changed to display a specific basic emotion (happiness, anger, fear, or sadness). Participants were asked to identify and then classify each displayed emotion. Before the task, a subsample of 46 participants underwent two salivary cortisol assessments. Individuals with global burnout were less accurate at recognizing others' emotional expressions of anger and fear, tending to misclassify these as happiness, compared to individuals without global burnout. Individuals with high burnout depersonalization were more accurate in recognizing happiness and less accurate in recognizing all negative emotions, with a tendency to misclassify the latter as positive ones, compared to healthcare workers with moderate/low depersonalization. Moreover, individuals with high depersonalization-but not participants with global burnout-were characterized by higher cortisol levels. These results suggest that the subjective burnout experience relates to an actual, but selective, reduction in the recognition of facial emotional expressions, characterized by a tendency to misclassify negative emotional expressions as positive ones, perhaps due to an enhanced seeking of positive social cues. This study adds to the understanding of emotional processing in burnout and paves the way for more nuanced studies on the role of altered processing of threat signals in the development and/or persistence of burnout., Competing Interests: The authors declare that they have no competing interests., (© 2021 Colonnello et al.)

Everyday life psychosocial stressors contribute to poor health and disease vulnerabilty. Means alternative to pharmacotherapy that are able to foster stress resilience are more and more under the magnifying glass of biomedical research. The aim of this study was to test stress resilience fostering properties of the self-administration of a cosmetic product enriched with essential oils. On day 0, fourty women, 25-50 years old, self-administered both the enriched cosmetic product (ECP) and a placebo one (PCP). Then, women were randomized for daily self-administration (from day 1 to 28) of either ECP ( n  = 20) or PCP ( n  = 20). On day 29, subjects underwent a psychosocial stress test (PST). Autonomic (heart rate and its variability) and neuroendocrine (salivary cortisol) parameters were assessed both on day 0 and 29. All subjects filled a number of psychological questionnaires in order to quantify anxiety, perceived stress, and mood profile, and were videorecorded during PST for non-verbal behavior evaluation. A single application of ECP produced an acute potentiation of cardiac parasympathetic modulation, which was not observed when placebo was used. Prolonged self-administration of ECP induced: (i) a dampening of the cortisol rise produced by PST, (ii) a reduction of state anxiety, (iii) a favorable change in mood profile, and (iv) a reduction of non-verbal behavior patterns that signal anxiety, motivational conflict and avoidance. In conclusion, this study suggests that the self-administration of a cosmetic cream enriched with essential oils should be considered as a stress resilience fostering strategy due to its favorable physiological, neuroendocrine and psychological effects.

Background: African Americans have the highest rates of hypertension-related disease of any ethnic group in the USA. Importantly, racism and discrimination have been linked to these higher rates of morbidity and mortality. Discrimination is deleterious not only to those that are the recipients of this unfair treatment but also to the partners and family members of those affected as well to those that perpetrate this bias., Purpose: In this paper, we identify a unique pattern of physiological response to unfair treatment, we have called the "cardiovascular conundrum." This pattern is characterized by greater heart rate variability and greater total peripheral resistance in African Americans compared to their European American counterparts., Methods and Results: We review the evidence supporting the existence of this pattern and propose several physiological and psychological factors that might underpin it. We also propose a number of factors that might help to mitigate the deleterious effects associated with it., Conclusions: Whereas the context of the current review is on Black/White disparities the framework we propose may be relevant to others exposed to unfair treatment. Ultimately, the systemic factors that perpetuate these inequalities will require that we first acknowledge and then face the challenges they present if we are to address the wealth and health disparities in our country., (© Society of Behavioral Medicine 2021. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Invasive alien plants are a major threat to biodiversity and they contribute to the unfavourable conservation status of habitats of interest to the European Community. In order to favour implementation of European Union Regulation no. 1143/2014 on invasive alien species, the Italian Society of Vegetation Science carried out a large survey led by a task force of 49 contributors with expertise in vegetation across all the Italian administrative regions. The survey summed up the knowledge on impact mechanisms of invasive alien plants in Italy and their outcomes on plant communities and the EU habitats of Community Interest, in accordance with Directive no. 92/43/EEC. The survey covered 241 alien plant species reported as having deleterious ecological impacts. The data collected illustrate the current state of the art, highlight the main gaps in knowledge, and suggest topics to be further investigated. In particular, the survey underlined competition as being the main mechanism of ecological impact on plant communities and Natura 2000 habitats. Of the 241 species, only Ailanthus altissima was found to exert an ecological impact on plant communities and Natura 2000 habitats in all Italian regions; while a further 20 species impact up to ten out of the 20 Italian administrative regions. Our data indicate that 84 out of 132 Natura 2000 Habitats (64%) are subjected to some degree of impact by invasive alien plants. Freshwater habitats and natural and semi-natural grassland formations were impacted by the highest number of alien species, followed by coastal sand dunes and inland dunes, and forests. Although not exhaustive, this research is the first example of nationwide evaluation of the ecological impacts of invasive alien plants on plant communities and Natura 2000 Habitats., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

The osteopathic community has long hypothesized that the autonomic nervous system (ANS) represents one of the putative substrates through which osteopathic manipulative treatment (OMT) can improve body functions that have been altered by musculoskeletal alterations. Heart rate variability (HRV) is an important physiological measure of cardiac ANS activity. Emerging evidence suggests that OMT is associated with HRV changes that (i) are indicative of a larger cardiac vagal modulation, (ii) are independent from the part of the body needing treatment, (iii) occur even in the absence of musculoskeletal alterations. Yet, many questions remain unanswered, the duration of these effects and the specificity of HRV responses to different OMT techniques being perhaps the most critical. Therefore, this paper discusses prospects for future applications of HRV for the study of the influence of OMT on ANS function. Moreover, based on existing studies and preliminary data on the effects of OMT on HRV in specific pathological (hypertension) and physiological (stress exposure and recovery from sport competition) conditions that are commonly associated with increased sympathetic and/or decreased vagal activity, we propose that HRV analysis could be exploited to evaluate the effectiveness of OMT as a preventive or complementary strategy in clinical and non-clinical conditions characterized by ANS imbalance., (Copyright © 2020 Carnevali, Lombardi, Fornari and Sgoifo.)

In recent years, increasing interest has been devoted to the physiological basis of self and other-oriented compassion. Heart rate variability (HRV) represents a promising candidate for such a role, given its association with soothing emotions and context appropriate prefrontal inhibitory control over threat-defensive responses. The aim of this study was to meta-analyze available studies on the association between compassion and HRV. Random-effect models were used. The analysis performed on sixteen studies that met inclusion criteria, yielded a significant association with a medium effect size (g = .54 95% CI [.24, .84], p < .0001). Results were not influenced by publication bias. After an extreme outlier's exclusion, the size of the association was still larger in studies that used time or frequency-domain indices of vagally-mediated HRV compared to those that used peak to trough estimates of respiratory sinus arrhythmia. Results are limited by the small number of studies included in the meta-analysis (n = 16) and are discussed in terms of indications for future research, given that existing data are highly heterogeneous and of poor methodological rigor., Competing Interests: Declaration of Competing Interest None., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Gamma aminobutyric acid (GABA) is the principal inhibitory neurotransmitter playing a key role in anxiety and depression disorders in mammals. Recent studies revealed that members of the gut microbiota are able to produce GABA modulating the gut-brain axis response. Among members of the human gut microbiota, bifidobacteria are well known to establish many metabolic and physiologic interactions with the host. In this study, we performed genome analyses of more than 1,000 bifidobacterial strains publicly available revealing that Bifidobacterium adolescentis taxon might represent a model GABA producer in human gastrointestinal tract. Moreover, the in silico screening of human/animal metagenomic datasets showed an intriguing association/correlation between B. adolescentis load and mental disorders such as depression and anxiety. Interestingly, in vitro screening of 82 B. adolescentis strains allowed identifying two high GABA producers, i.e. B. adolescentis PRL2019 and B. adolescentis HD17T2H, which were employed in an in vivo trial in rats. Feeding Groningen rats with a supplementation of B. adolescentis strains, confirmed the ability of these microorganisms to stimulate the in vivo production of GABA highlighting their potential implication in gut-brain axis interactions.

Stressful experiences can be transmitted among individuals through social interactions. Like humans, rodents are social creatures whose behavior and physiology can be influenced by the emotional state of fellow rodents. This paper will review rodent studies which have explored two conditions of potential social stress contagion using the social defeat paradigm. In the vicarious social defeat model, mice and rats that witness a conspecific being socially defeated exhibit physiological stress responses and develop a host of depressive- and anxiety-like behavioral deficits. Likewise, social interaction with a stressed partner in the aftermath of social defeat stress results in physiological stress responses and social avoidance behavior. After summarizing the existing literature on this newly emerging area of social defeat stress contagion in rodents, we will discuss the potential utility of these rodent models for investigating the neurobiological processes and sensory channels of information that allow for the spread of psychophysiological effects of stress across individuals., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Pharmacological inhibition of the enzyme fatty acid amide hydrolase (FAAH), which terminates signaling of the endocannabinoid N-arachidonoylethanolamine (or anandamide, AEA), exerts favourable effects in rodent models of stress-related depression. Yet although depression seems to be more common among women than men and in spite of some evidence of sex differences in treatment efficacy, preclinical development of FAAH inhibitors for the pharmacotherapy of stress-related depression has been predominantly conducted in male animals. Here, adult female rats were exposed to six weeks of social isolation and, starting from the second week, treated with the FAAH inhibitor URB694 (0.3 mg/kg/day, i.p.) or vehicle. Compared to pair-housed females, socially isolated female rats treated with vehicle developed behavioral (mild anhedonia, passive stress coping) and physiological (reduced body weight gain, elevated plasma corticosterone levels) alterations. Moreover, prolonged social isolation provoked a reduction in brain-derived neurotrophic factor (BDNF) and AEA levels within the hippocampus. Together, these changes are indicative of an increased risk of developing a depressive-like state. Conversely, pharmacological inhibition of FAAH activity with URB694 restored both AEA and BDNF levels within the hippocampus of socially isolated rats and prevented the development of behavioral and physiological alterations. These results suggest a potential interplay between AEA-mediated signaling and hippocampal BDNF in the pathogenesis of depression-relevant behaviors and physiological alterations and antidepressant action of FAAH inhibition in socially isolated female rats., Competing Interests: Conflict of Interest All authors declare that they have no conflicts of interest., (Copyright © 2020. Published by Elsevier B.V.)

Prolonged or repeated activation of the stress response can have negative psychological and physical consequences. The prefrontal cortex (PFC) is thought to exert an inhibitory influence on the activity of autonomic and neuroendocrine stress response systems. In this study, we further investigated this hypothesis by increasing PFC excitability using transcranial direct current stimulation (tDCS). Healthy male participants were randomized to receive either anodal (excitatory) tDCS ( n  = 15) or sham stimulation ( n  = 15) over the left dorsolateral prefrontal cortex (DLPFC) immediately before and during the exposure to a psychosocial stress test. Autonomic (heart rate (HR) and its variability) and neuroendocrine (salivary cortisol) parameters were assessed. One single session of excitatory tDCS over the left DLPFC (i) reduced HR and favored a larger vagal prevalence prior to stress exposure, (ii) moderated stress-induced HR acceleration and sympathetic activation/vagal withdrawal, but (iii) had no effect on stress-induced cortisol release. However, anodal tDCS over the left DLPFC prevented stress-induced changes in the cortisol awakening response. Finally, participants receiving excitatory tDCS reported a reduction in their levels of state anxiety upon completion of the psychosocial stress test. In conclusion, this study provides first insights into the efficacy of one single session of excitatory tDCS over the left DLPFC in attenuating autonomic and neuroendocrine effects of psychosocial stress exposure. These findings might be indicative of the important role of the left DLPFC, which is a cortical target for noninvasive brain stimulation treatment of depression, for successful coping with stressful stimuli.

The variability of heart period, measured as the time distance between two consecutive QRS complexes from the electrocardiogram (RR), was exploited to infer cardiac vagal control, while the variability of the duration of the electrical activity of the heart, measured as the time interval from Q-wave onset to T-wave end (QT), was proposed as an indirect index of cardiac sympathetic modulation. This study tests the utility of the concomitant evaluation of RR variability (RRV) and QT variability (QTV) markers in typifying cardiac autonomic control of humans under different experimental conditions and of rat groups featuring documented differences in resting sympatho-vagal balance. We considered: (i) 23 healthy young subjects in resting supine position (REST) undergoing head-up tilt at 45° (T45) and 90° (T90) followed by recovery to the supine position; (ii) 9 Wistar (WI) and 14 wild-type Groningen (WT) rats in unstressed conditions, where the WT animals were classified as non-aggressive (non-AGG, n = 9) and aggressive (AGG, n = 5) according to the resident intruder test. In humans, spectral analysis of RRV and QTV was performed over a single stationary sequence of 250 consecutive values. In rats, spectral analysis was iterated over 10-min recordings with a frame length of 250 beats with 80% overlap and the median of the distribution of the spectral markers was extracted. Over RRV and QTV we computed the power in the low frequency (LF, from 0.04 to 0.15 Hz in humans and from 0.2 to 0.75 Hz in rats) band (LF RR and LF QT ) and the power in the high frequency (HF, from 0.15 to 0.5 Hz in humans and from 0.75 to 2.5 Hz in rats) band (HF RR and HF QT ). In humans the HF RR power was lower during T90 and higher during recovery compared to REST, while the LF QT power was higher during T90. In rats the HF RR power was lower in WT rats compared to WI rats and the LF QT power was higher in AGG than in non-AGG animals. We concluded that RRV and QTV provide complementary information in describing the functioning of vagal and sympathetic limbs of the autonomic nervous system in humans and rats., (Copyright © 2019 De Maria, Bari, Sgoifo, Carnevali, Cairo, Vaini, Catai, de Medeiros Takahashi, Dalla Vecchia and Porta.)

Stress related to parenting a child with autism spectrum disorder can differently affect caregiver's physiological reactivity to acute stress. Here, parental stress levels, psychological characteristics, and coping strategies were assessed alongside measures of heart rate, heart rate variability, and cortisol during a psychosocial stress test in mothers of children with ASD (M-ASD, n = 15) and mothers of typically developing children (n = 15). M-ASD reported significantly higher levels of parental stress, anxiety, negative affectivity, social inhibition, and a larger preference for avoidance strategies. M-ASD showed larger heart rate and cortisol responses to the psychosocial stress test. A positive relationship was found between parental stress levels and the magnitude of the cortisol stress response in both groups. The present findings indicate exaggerated physiological reactivity to acute psychosocial stress in M-ASD and prompt further research to explore the role of individual differences in mediating the effects of parental stress on physiological stress responses., (©2019 John Wiley & Sons, Ltd.)

Bifidobacteria commonly constitute the most abundant group of microorganisms in the healthy infant gut. Their intestinal establishment is believed to be maternally driven, and their acquisition has even been postulated to occur during pregnancy. In the current study, we evaluated bifidobacterial mother-to infant transmission events in a rat model by means of quantitative PCR (qPCR), as well as by Internally Transcribed Spacer (ITS) bifidobacterial profiling. The occurrence of strains supplied by mothers during pregnancy to their corresponding newborns was observed and identified by analysis immediately following C-section delivery. These findings provide intriguing support for the existence of an unknown route to facilitate bifidobacterial transfer during the very early stages of life.

Sleep is altered in response to an immune challenge: non-rapid eye movement (NREM) sleep is increased and fragmented, REM sleep is inhibited. Sleep and immune response are affected by stress: several stressors inhibit sleep and increase waking time; stress-induced cortisol secretion affects the immune response, with immunosuppressive effects. Different levels of trait aggressiveness are associated with specific patterns of neuroendocrine and autonomic stress responsiveness. Aim of this study was to test the hypothesis that trait aggressiveness, by affecting response to stressors, modifies sleep alterations induced by the activation of the immune response. To this aim, rats were selected on the basis of their latency time to attack a male intruder in the resident-intruder test. Animals were instrumented for chronic recordings of sleep-wake activity and injected, intraperitoneally, with an immune challenge (250 μg/kg lipopolysaccharide - LPS, a component of gram-negative bacterial cell wall). Here we report that high aggressive (HA) rats responded to an immune challenge with a 24-h long increase in cortical brain temperature. During the first 12 post-injection hours, HA rats also responded with a prolonged increase in NREM sleep amount, and a 5-h long and continuous inhibition of REM sleep. In HA rats, the LPS-induced increase in the amount of time spent in NREM sleep was due to an increase in the number of episodes of this sleep phase, without any change in the bout duration. The LPS-induced REM sleep inhibition observed in HA rats was due to a decrease in both the number and duration of REM sleep bouts. In HA rats, during REM sleep, LPS administration significantly reduced the power of the EEG theta band. In non-aggressive (NA) rats, in response to LPS administration, cortical brain temperature was increased only for two hours, NREM sleep was unaffected, and REM sleep inhibition was scattered along the first 8 post-injection hours. The LPS-induced changes in the number of NREM sleep bouts of NA rats were limited to few and scattered hours, with a change in bout duration only in a single hour. A combination of decreases, in few hours, in both REM sleep bouts and their duration contributed to the REM sleep inhibition observed in NA rats. In NA rats, the power of EEG theta band was not modified, during REM sleep, by LPS administration. Gross motor activity was inhibited in both HA and NA rats. Results of this study show that trait aggressiveness affects febrile and sleep responses to an immune challenge., (Copyright © 2019 Elsevier Inc. All rights reserved.)

The inflammatory reflex is known as the body's primary defense against infection and has been implicated in a number of diseases. The magnitude of the inflammatory response is important, as an extreme or insufficient response can be differentially harmful to the individual. Converging evidence suggests that the autonomic nervous system (ANS) regulates the inflammatory reflex. Heart rate variability (HRV) can be separated into components that primarily reflect parasympathetic (PNS) or vagal activity (i.e., indices of vagally mediated HRV) and a combination of both sympathetic (SNS) and PNS influences. Given the physiological relation between the vagus and inflammatory processes, one would expect to find higher HRV, especially indices of vagally-mediated HRV, to be associated with decreased levels of inflammation via the cholinergic anti-inflammatory pathway. However, existing findings here are mixed, such that studies have also shown a positive association between indices of HRV and markers of inflammation. Therefore, the present meta-analysis aimed to synthesize existing studies, estimating the general direction and strength of the relationship between different indices of HRV and inflammatory markers. A systematic search of the literature yielded 2283 studies that were screened for inclusion eligibility (159 studies eligible for inclusion); in sum, 51 studies reported/provided adequate information for inclusion in meta-analyses. Results generally showed negative associations between indices of HRV and markers of inflammation. In this regard, the standard deviation of R-R intervals (SDNN) and power in the high frequency band of HRV (HF-HRV) showed the strongest and most robust associations with inflammatory markers compared to other time- and frequency-domain measures of HRV. Overall, we propose that indices of HRV can be used to index activity of the neurophysiological pathway responsible for adaptively regulating inflammatory processes in humans., (Copyright © 2019 Elsevier Inc. All rights reserved.)