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Dysphoric individuals perceive mental tasks as more demanding and show increased cardiovascular responses during the performance of easy cognitive tasks. Recent research on action shielding indicates that providing individuals with personal control over their tasks can mitigate the effects of manipulated affective states on cardiovascular responses reflecting effort. We investigated whether the shielding effect of personal choice also applies to the effect of dispositional negative mood on effort. N = 125 university students with high (dysphoric) versus low (nondysphoric) depressive symptoms engaged in an easy cognitive task either by personal choice or external assignment. As expected, dysphoric individuals showed significantly stronger cardiac PEP reactivity during task performance when the task was externally assigned. Most importantly, this dysphoria effect disappeared when participants could ostensibly personally choose their task. Our findings show that the previously observed shielding effect of personal action choice against incidental affective stimulation also applies to dispositional negative affect. Dysphoric individuals show increased cardiovascular responses when performing easy cognitive tasks. This study revealed that personal control over the task to be performed can attenuate the effects of dispositional negative affect on effort‐related cardiovascular responses. The present study extends recent research on action shielding. The shielding effect of personal choice against incidental affective stimulation also applies to dispositional negative affect related to individuals' depressive symptoms. [ABSTRACT FROM AUTHOR]

Callous‐unemotional (CU) traits have important utility in distinguishing individuals exhibiting more severe and persistent antisocial behavior, and our understanding of reward processing and CU traits contributes to behavioral modification. However, research on CU traits often investigated reward alongside punishment and examined solely on average reward reactivity, neglecting the reward response pattern over time such as habituation. This study assessed individuals' pre‐ejection period (PEP), a sympathetic nervous system cardiac‐linked biomarker with specificity to reward, during a simple reward task to investigate the association between CU traits and both average reward reactivity and reward response pattern over time (captured as responding trajectory). A heterogeneous sample of 126 adult males was recruited from a major metropolitan area in the US. Participants reported their CU traits using the Inventory of Callous‐Unemotional Traits and completed a simple reward task while impedance cardiography and electrocardiogram were recorded to derive PEP. The results revealed no significant association between average PEP reward reactivity and CU traits. However, CU traits predicted both linear and quadratic slopes of the PEP reactivity trajectory: individuals with higher CU traits had slower habituation initially, followed by a rapid habituation in later blocks. Findings highlight the importance of modeling the trajectory of PEP reward response when studying CU traits. We discussed the implications of individuals with high CU traits having the responding pattern of slower initial habituation followed by rapid habituation to reward and the possible mechanisms. We examined the association between Pre‐ejection Period (PEP), a peripheral marker for central dopamine reactivity to reward, and Callous‐Unemotional (CU) Traits. CU traits were not associated with overall PEP reward reactivity but with the PEP responding features over time: those with high CU traits had slower initial habituation followed by a faster recovery to baseline. This finding highlights the importance of examining the time course of reward responding in research on CU traits. [ABSTRACT FROM AUTHOR]

This article presents an experiment (N = 127 university students) testing whether the previously found impact of conflict primes on effort‐related cardiac response is moderated by objective task difficulty. Recently, it has been shown that primed cognitive conflict increases cardiac pre‐ejection period (PEP) reactivity—an index of effort intensity—during the performance of relatively easy tasks. This effect could be attributed to conflict‐related negative affect. Consequently, as it has been shown for other types of negative affect, we expected conflict primes' effect to be task‐context dependent and thus to be moderated by objective task difficulty. In a between‐persons design, we manipulated conflict via embedded pictures of conflict‐related vs. non‐conflict‐related Stroop items in a memory task. We expected primed conflict to increase effort in a relatively easy version of the task but to lead to disengagement when task difficulty was objectively high. PEP reactivity corroborated our predictions. Rather than always increasing effort, cognitive conflict's effect on resource mobilization was context‐dependent and resulted in weak responses in a difficult task. Cognitive conflict is aversive and can thus trigger effortful adjustments. The implicit‐affect‐primes‐effort model posits, however, that affective stimuli's impact on effort also depends on objective task difficulty—like that of cognitive conflict primes. As predicted, primed conflict increased cardiac pre‐ejection responses in an easy task. However, conflict led to low responses in a difficult task. That is, conflict is not effortful per se. Rather, its impact on resource mobilization is task‐context dependent. [ABSTRACT FROM AUTHOR]

During times of stress, we look to close others for support. Social support conversations are critical for relationship maintenance and well‐being. Yet, certain ways of talking about problems—such as co‐ruminating—can exacerbate stress. Since social support and co‐rumination are both dyadic processes, it is important to examine physiological responses during these conversations in a dyadic manner. Little research has examined physiological synchrony of the sympathetic nervous system (SNS) during social support conversations or co‐ruminative conversations. The current research capitalizes on an experimental manipulation of co‐rumination using a sample of close friends (147 dyads) and romantic partners (113 dyads) to examine physiological covariation in the context of support. Across both samples, dyads exhibited significant physiological covariation in pre‐ejection period reactivity (PEP). Contrary to our hypothesis, dyads in the co‐rumination condition did not show more covariation. Close friend dyads did, however, exhibit more covariation as compared to romantic dyads. We also found significant variability in physiological covariation across dyads, with a minority of dyads exhibiting negative covariation of PEP reactivity. The homogeneity of the samples limits the generalizability of the findings and highlights the need for more diverse samples in future work. These findings underline the need for further exploration into the mechanisms that contribute to distinct patterns of physiological synchrony, the conditions in which negative synchrony occurs, and what predicts especially strong positive synchrony. This work extends our understanding of physiological synchrony of the sympathetic nervous system during support conversations and emphasizes the importance of considering heterogeneity in physiological processes. Impact statement: This research capitalizes on two dyadic experiments to examine physiological covariation during supportive conversations, examining whether certain ways of providing support affects synchrony. The findings show that not only does physiological covariation of the sympathetic nervous system occur, but it is variable across dyads and stronger for close friends as compared to romantic partners. [ABSTRACT FROM AUTHOR]

Since personal choice fosters commitment and shields action execution against potentially conflicting influences, two laboratory experiments with university students (N = 228) tested whether engaging in action by personal choice versus external assignment of task characteristics moderates the effect of irrelevant acoustic noise on cardiovascular responses reflecting effort. Participants who could personally choose the stimulus color of moderately difficult cognitive tasks were expected to be shielded against the irrelevant noise. By contrast, when the stimulus color was externally assigned, we predicted receptivity for the irrelevant noise to be high. As expected, in both experiments, participants in the assigned color condition showed stronger cardiac pre‐ejection period reactivity during task performance when exposed to noise than when working in silence. On the contrary, participants who could choose the stimulus color were shielded against the noise effect on effort. These findings conceptually replicate and extend research on the action shielding effect by personal choice and hold practical implications for occupational health. Acoustic noise during cognitive task performance can increase effort. Our two studies identify an important moderator of this effect: personal choice. In both studies, the opportunity to personally choose task characteristics shielded sympathetically mediated cardiovascular reactivity reflecting effort against noise influences during the performance of moderately difficult cognitive tasks. As predicted, sympathetically mediated cardiovascular reactivity was the strongest in tasks with externally assigned characteristics under noise exposure. [ABSTRACT FROM AUTHOR]

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Implicitly processed pictures of facial expressions of emotions have been found to systematically influence sympathetically mediated cardiovascular reactivity during task performance. According to the Implicit‐Affect‐Primes‐Effort model, this happens because different affect primes activate the concepts of performance ease versus performance difficulty. Grounded in a recent action shielding model, our laboratory experiment (N = 129 university students) tested whether engaging in action by personal choice can immunize against those implicit affective influences on effort. Participants worked on an objectively difficult cognitive task, which was either externally assigned or ostensibly personally chosen. As predicted, participants in the assigned task condition showed weaker cardiac pre‐ejection period reactivity during task performance, reflecting disengagement, when they were primed with sadness than when they were exposed to anger primes. Most relevant, this affect prime effect disappeared when participants could ostensibly choose their task themselves. These findings replicate previous research on implicit affect's impact on sympathetically mediated cardiac response and extend the literature on action shielding by personal choice effects to implicit affective influences on action execution. This study extends evidence on the action‐shielding model to affect prime effects on sympathetically mediated cardiovascular response. Personal task choice could shield against the effect of implicitly processed sadness primes on sympathetically mediated cardiac response that were evident when the task was assigned. Importantly, the present study also adds to the list of moderators for implicit affective influences on effort. The results suggest that implicit priming is less automatic and uncontrollable as previously thought. [ABSTRACT FROM AUTHOR]

Aging ushers in numerous disruptions to autonomic nervous system (ANS) function. Although the effects of aging on ANS function at rest are well characterized, there is surprising variation in reports of age‐related differences in ANS reactivity to psychosocial stressors, with some reports of decreases and other reports of increases in reactivity with age. The sources of variation in age‐related differences are largely unknown. Nonhuman primate models of socioaffective aging may help to uncover sources of this variation as nonhuman primates share key features of human ANS structure and function and researchers have precise control over the environments in which they age. In this report, we assess how response patterns to dynamic socioaffective stimuli in the parasympathetic and sympathetic branches of rhesus monkeys (Macaca mulatta) ANS differ in aged compared to middle‐aged monkeys. We find that respiratory sinus arrhythmia, a cardiac indicator of activity in the parasympathetic branch of the ANS, exhibits age‐related disruptions in responding while monkeys view videos of conspecifics. This suggests that there are evolutionarily conserved mechanisms responsible for the patterns of affective aging observed in humans and that aged rhesus monkeys are a robust translational model for human affective aging. Understanding the socioemotional consequences of age‐related changes to people's physiological function is necessary for promoting wellbeing in aging populations. Such investigations in humans are difficult due to their protracted lifespans and the presence of confounds between age, health, and wellbeing. Here, we adopt a monkey model to evaluate how aging impacts autonomic reactivity to socioaffective stimuli and uncover phylogenetically shared features of psychophysiological aging between monkeys and humans. [ABSTRACT FROM AUTHOR]

Maternal substance use may interfere with optimal parenting, lowering maternal responsiveness during interactions with their children. Previous work has identified maternal autonomic nervous system (ANS) reactivity to parenting‐relevant stressors as a promising indicator of real‐world parenting behaviors. However, less is known about the extent to which individual differences in emotion dysregulation and reward processing, two mechanisms of substance use, relate to maternal ANS reactivity in substance‐using populations. The current study examined associations among emotion dysregulation, reward responsiveness, and ANS reactivity to an infant cry task among 77 low‐income and substance‐using women who were either pregnant (n = 63) or postpartum (n = 14). Two indicators of ANS functioning were collected during a 9 min computerized infant cry task (Crybaby task): respiratory sinus arrhythmia (RSA) and pre‐ejection period. Mothers also completed self‐reported measures of emotion dysregulation and reward responsiveness. Analyses revealed that trait emotion regulation was associated with RSA reactivity to the Crybaby task, such that greater emotion dysregulation was associated with greater RSA reduction during the infant cry task than lower emotion dysregulation. Reward responsiveness was not significantly associated with either indicator of ANS reactivity to the task. Findings revealed distinct patterns of associations linking emotion dysregulation with ANS reactivity during a parenting‐related computerized task, suggesting that emotion regulation may be a key intervention target for substance‐using mothers. [ABSTRACT FROM AUTHOR]

This article presents a quasi‐experiment (N = 79 university students) testing whether individual differences in action‐state orientation moderate primed cognitive conflict's effects on sympathetically mediated cardiac response during task performance reflecting effort. Action control theory posits that action‐oriented individuals are less receptive to distracting affective stimuli during goal pursuit than state‐oriented individuals because action‐orientation is related to higher volitional skills. Therefore, we expected that action‐oriented individuals should be shielded against conflict primes' effect on effort‐related responses in the cardiovascular system. By contrast, state‐oriented individuals should be more sensitive to irrelevant negative affective stimulation and therefore mobilize higher resources under such conditions. Responses of the cardiac pre‐ejection period (PEP) during a moderately difficult short‐term memory task corroborated these predictions. The present findings provide the first evidence that individual differences in action‐state orientation indeed moderate previously demonstrated cognitive conflict priming effects on effort‐related cardiac response and extend recent findings on action shielding. Taking a volitional perspective, action control theory predicts that individual differences in action‐state orientation—an action control capacity—moderate individuals' sensitivity to affective distractors. As predicted, state‐oriented individuals showed stronger cardiac pre‐ejection period reactivity after conflict primes than after non‐conflict primes, while action‐oriented participants showed low reactivity in both conditions. That is, action‐orientation shields individuals against irrelevant negative affective stimulation on effort‐related cardiac response. [ABSTRACT FROM AUTHOR]

Autonomic nervous system (ANS) activity is a core and central component of emotion and motivated action. The myriad social and cognitive challenges faced by humans require flexible modulation of ANS activity for different contexts. In this study, simultaneous activity of the parasympathetic and sympathetic nervous system was measured using respiratory sinus arrhythmia (RSA) and pre-ejection period (PEP), respectively. Samples combined four previous studies (N = 325, 63% female, aged 15-55) in which RSA and PEP were collected continuously during a resting baseline and an acute stressor, the Trier Social Stress Task. The concurrent relation between RSA and PEP responses was modelled in order to determine the extent to which SNS and PNS activity is correlated across the task within and between participants, and whether this correlation was moderated by age, race, sex, or baseline RSA and PEP. Overall, RSA and PEP were reciprocally coupled. However, recovery from a stressor was characterized by coactivation. Individuals also vary in the extent to which their SNS and PNS are reciprocally coupled; women, younger adults, and individuals with higher baseline RSA showed more reciprocal coupling than men, older adults, and those with lower baseline RSA, respectively, reflecting greater coordination of physiological responding in the former groups.

A quasi experiment (N = 100 university students) tested whether individual differences in action‐state orientation moderate task difficulty effects on resource mobilization assessed as cardiovascular response. According to action control theory, action‐oriented individuals have higher self‐regulation capacities in demanding situations than state‐oriented persons. Action‐orientated individuals should also self‐generate positive affect in face of obstacles. Therefore, drawing on Wright's (1998) ability extension of motivational intensity theory and research on affective influences on effort‐related cardiovascular response, we expected that action‐orientation should lead to stronger effort‐related cardiovascular responses in a difficult task, while state‐orientation should do so in an easy task. Reactivity of cardiac pre‐ejection period (PEP) during performance on a short‐term memory task corroborated this hypothesis. The present findings provide the first evidence of a link between action‐state orientation and effort‐related responses in the cardiovascular system. Action‐control theory predicts that individual differences in action‐state orientation—an action‐control capacity—moderate task difficulty effects on effort intensity. Our experiment found the first conclusive evidence for this idea. As predicted, action‐oriented individuals showed stronger cardiac pre‐ejection period reactivity in a difficult short‐term memory task, while state‐oriented participants did so when the task was easy. That is, action‐state orientation moderates task difficulty effects on effort‐related cardiac response. [ABSTRACT FROM AUTHOR]

Ample evidence suggests that pain leads to additional demand in cognitive functioning, presumably due to its negative affective component and its propensity to capture attention. To highlight the role of motivational incentive, two experiments tested the combined effect of pain and monetary incentive on effort‐related cardiovascular response during cognitive performance. In both studies, healthy volunteers received individually adjusted painful or nonpainful thermal stimulations during a difficult cognitive task (4‐back task in Experiment 1; short‐term memory task in Experiment 2) and expected high (12 Swiss Francs in both experiments) or low monetary incentive (1 Swiss Franc in Experiment 1; 0.10 Swiss Francs in Experiment 2) for successful performance. Effort was primarily assessed as changes in cardiac pre‐ejection period (PEP). We predicted pain to increase subjective task difficulty during cognitive performance. Moreover, according to motivational intensity theory, we expected this to increase effort only when high effort was justified by high monetary incentive. Correspondingly, pain should lead to low effort (disengagement) when monetary incentive was low. Effort in the nonpainful conditions was expected to fall in between these conditions. The results of both studies support our predictions. Our findings provide the first evidence for the moderating effect of monetary incentive on physical pain's impact on effort‐related cardiovascular response. Accordingly, motivational incentives can counteract effort deficits associated with pain. The current findings further advance our understanding of pain's impact on effort‐related cardiovascular response by showing for the first time the moderating effect of monetary incentive. This suggests that it is possible to counteract effort deficits associated with pain, which may be beneficial from a clinical perspective. [ABSTRACT FROM AUTHOR]

Two experiments with N = 221 university students investigated the impact of primed cognitive conflict on effort assessed as cardiac response in tasks that were not conflict‐related themselves. Manifest cognitive conflict in cognitive control tasks is confounded with objective response difficulty (e.g., in incongruent Stroop task trials). This makes conclusions about the effortfulness of cognitive conflict itself difficult. We bypassed this problem by administrating pictures of congruent versus incongruent Stroop task stimuli as conflict primes. As predicted, primed cognitive conflict increased cardiac pre‐ejection period (PEP) responses in an easy attention task in Experiment 1. Accordingly, cognitive conflict itself is indeed effortful. This effect was replicated in an easy short‐term memory task in Experiment 2. Moreover, as further predicted, the primed cognitive conflict effect on PEP reactivity disappeared when participants could personally choose task characteristics. This latter effect corresponds to other recent evidence showing that personal action choice shields against incidental affective influences on action execution and especially on effort‐related cardiovascular response. Cognitive conflict is said to be effortful, but conclusive evidence is lacking. One problem is that conflict in cognitive control tasks is confounded with response difficulty. We bypassed this problem by administrating pictures of congruent vs incongruent Stroop task stimuli as conflict primes. Primed conflict indeed increased responses of cardiac pre‐ejection period in tasks that were neither difficult nor conflict‐related themselves. Furthermore, participants' personal choice of task characteristics could eliminate the conflict effect on effort. [ABSTRACT FROM AUTHOR]

This experiment (N = 113) tested whether personal choice vs. external assignment of task characteristics moderates the effect of incidental affective stimulation on effort-related cardiovascular response in a " do your best " task context. When participants could choose themselves the color of the stimuli (i.e., a series of letters to be recalled) used in a memory task, we expected high task commitment and willingness to mobilize resources, strong action shielding, and thus low receptivity for incidental affective influences. By contrast, when the color was externally assigned, we expected low willingness to mobilize resources, weak action shielding, and thus strong affective influences on effort. As predicted, participants in the assigned color condition showed stronger cardiac pre-ejection period reactivity during task execution when exposed to sad music than when exposed to happy music. These music effects did not appear among participants who could personally choose the color. Here, effort was high independently of the happy or sad background music. The present study demonstrates the moderating effect of personal choice on resource mobilization in a task of unfixed difficulty with happy and sad background music as incidental affective influence. • Participants could choose task characteristics or were externally assigned to them. • During the task, participants tried to do their best and were exposed to happy or sad background music. • Without choice, sad music led to stronger cardiac PEP reactivity than happy music. • This music effect disappeared when participants got to personally choose their stimulus color. [ABSTRACT FROM AUTHOR]

PurposeThe pulse-wave-velocity, is used for indirect, cuff-less, continuous blood pressure estimation. It is commonly detected by measuring the time delay between a defined point in an ECG and the arrival of the peripheral pulse wave (e.g., oxygen saturation sensor). The period between electrical stimulation of the heart (ECG) and actual blood ejection from the heart is called the pre-ejection period (PEP). This study aims at characterizing the PEP under mental and physical stress with focus on its relations to other cardiovascular parameters such as heart rate and importance for blood pressure (BP) estimation.MethodsWe measured the PEP in 71 young adults at rest, under mental (TSST) and physical stress (ergometer) via impedance-cardiography.ResultsThe PEP is highly dependent on mental and physical load. It is strongly correlated with indicators of sympathetic strain (p < 0.001). At rest (mean 104.5 ms), the PEP shows a high interindividual variability but small intraindividual variability. Mental stress decreases the PEP by 16% (mean 90.0 ms) while physical stress halves PEP (mean 53.9 ms). The PEP does correlate differently with heart rate under differing circumstances (rest: R2 0.06, mental stress: R2 0.29, physical stress: R2 0.65). Subsequently, using PEP and heart rate enables the discrimination of rest, mental and physical strain with a positive predictive value of 93%.ConclusionThe PEP is a cardiovascular parameter with large interindividual variability at rest and subject-depended dynamic under load which is of great importance for ECG-based pulse-wave-velocity (PWV) determination. Considering its variability and large impact on the pulse arrival time, PEP is a crucial factor in PWV based BP estimation.

Pre‐ejection period (PEP), an indicator of sympathetic nervous system activity, is useful in psychophysiology and cardiovascular studies. Accurate PEP measurement is challenging and relies on robust identification of the timing of aortic valve opening, marked as the B point on impedance cardiogram (ICG) signals. The ICG sensitivity to noise and its waveform's morphological variability makes automated B point detection difficult, requiring inefficient and cumbersome expert visual annotation. In this article, we propose a machine learning‐based automated algorithm to detect the aortic valve opening for PEP measurement, which is robust against noise and ICG morphological variations. We analyzed over 60 hr of synchronized ECG and ICG records from 189 subjects. A total of 3657 averaged beats were formed using our recently developed ICG noise removal algorithm. Features such as the averaged ICG waveform, its first and second derivatives, as well as high‐level morphological and critical hemodynamic parameters were extracted and fed into the regression algorithms to estimate the B point location. The morphological features were extracted from our proposed "variable" physiologically valid search‐window related to diverse B point shapes. A subject‐wise nested cross‐validation procedure was performed for parameter tuning and model assessment. After examining multiple regression models, Adaboost was selected, which demonstrated superior performance and higher robustness to five state‐of‐the‐art algorithms that were evaluated in terms of low mean absolute error of 3.5 ms, low median absolute error of 0.0 ms, high correlation with experts' estimates (Pearson coefficient = 0.9), and low standard deviation of errors of 9.2 ms. For reproducibility, an open‐source toolbox is provided. Accurate computation of pre‐ejection period (PEP), an index of sympathetic nervous system activity, depends upon reliable detection of aortic valve opening (B point on impedance cardiogram (ICG)). Due to ICG waveform morphological variability, automated B point detection is challenging and requires time‐consuming visual annotations. We present a machine learning‐based automated B point detection algorithm that addresses several limitations imposed by other methods and can calculate PEP in an efficient, fully automated, and reproducible manner. [ABSTRACT FROM AUTHOR]

Temperamental risk, such as surgency, negative affect, and poor effortful control, has been posited as a predictor of externalizing symptom development. However, autonomic nervous system (ANS) activity underlying processes of reactivity and regulation may moderate associations between early temperament and later externalizing behaviors during early childhood. The aim of the present study was to examine how interactions between resting sympathetic (SNS) and parasympathetic (PNS) activity at age 5 may moderate associations between temperamental risk at age 3 and externalizing behavior at age 6 (n = 87). Results demonstrate different interactions between resting ANS activity and temperamental risk to predict externalizing behaviors. For children with lower SNS activation at rest, surgency was positively associated with externalizing behaviors. Negative affect was positively associated with externalizing behaviors except when there were either high levels of SNS and PNS activity or low levels of SNS and PNS activity. Effortful control was not associated with externalizing behaviors, though SNS and PNS activity interacted to predict externalizing behaviors after accounting for effortful control. Taken together, the results highlight the importance to examine multisystem resting physiological activity as a moderator of associations between temperamental risk and the development of externalizing behaviors. [ABSTRACT FROM AUTHOR]

Rationale: Pre-ejection period (PEP) and T-wave amplitude (TWA) have been used to assess sympathetic nervous system (SNS) activity. Here we report two single-blinded, placebo-controlled intravenous (IV) drug application studies in which we pharmacologically modified SNS activity with epinephrine (study 1) as well as dexmedetomidine (alpha2-agonist) and yohimbine (alpha2-antagonist) (study 2). Restricted heart rate (HR) intervals were analyzed to avoid confounding effects of HR changes. Objective: Study 1 served to replicate previous findings and to validate our approach, whereas study 2 aimed to investigate how modulation of central SNS activity affects PEP and TWA. Methods: Forty healthy volunteers (58% females) participated in study 1 (between-subject design). Twelve healthy men participated in study 2 (within-subject design). TWA and PEP were derived from ECG and impedance cardiography, respectively. Results: Epinephrine shortened PEP and induced statistically significant biphasic TWA changes. However, although the two alpha2-drugs significantly affected PEP as expected, no effects on TWA could be detected. Conclusion: PEP is better suited to reflect SNS activity changes than TWA. [ABSTRACT FROM AUTHOR]

Pre‐ejection period (PEP) is an index of sympathetic nervous system activity that can be computed from electrocardiogram (ECG) and impedance cardiogram (ICG) signals, but sensitive to speech/motion artifact. We sought to validate an ICG noise removal method, three‐stage ensemble‐average algorithm (TEA), in data acquired from a clinical trial comparing active versus sham non‐invasive vagal nerve stimulation (tcVNS) after standardized speech stress. We first compared TEA's performance versus the standard conventional ensemble‐average algorithm (CEA) approach to classify noisy ICG segments. We then analyzed ECG and ICG data to measure PEP and compared group‐level differences in stress states with each approach. We evaluated 45 individuals, of whom 23 had post‐traumatic stress disorder (PTSD). We found that the TEA approach identified artifact‐corrupted beats with intraclass correlation coefficient > 0.99 compared to expert adjudication. TEA also resulted in higher group‐level differences in PEP between stress states than CEA. PEP values were lower in the speech stress (vs. baseline rest) group using both techniques, but the differences were greater using TEA (12.1 ms) than CEA (8.0 ms). PEP differences in groups divided by PTSD status and tcVNS (active vs. sham) were also greater when using the TEA versus CEA method, although the magnitude of the differences was lower. In conclusion, TEA helps to accurately identify noisy ICG beats during speaking stress, and this increased accuracy improves sensitivity to group‐level differences in stress states compared to CEA, suggesting greater clinical utility. Although impedance cardiography is a promising method for detecting mortality in the general population, hypertension management, and stress assessment in psychophysiology research, its effectiveness can be severely limited by artifacts caused by speaking and movement. We present a validation study for a three‐stage ensemble‐average noise removal method during speaking tasks and show that this method more accurately identifies noisy signals resulting in better classification of stress states than the conventional method. The proposed method can also be applied to many other settings in which motion may lead to misclassification of cardiac physiology based on impedance cardiogram signal. [ABSTRACT FROM AUTHOR]

Trauma patients may suffer significant blood loss, and noninvasive methods to diagnose hypovolemia in these patients are needed. Physiologic effects of hypovolemia, aiming to maintain blood pressure, are largely mediated by increased sympathetic nervous activity. Trauma patients may however experience pain, which also increases sympathetic nervous activity, potentially confounding measures of hypovolemia. Elucidating the common and separate effects of the two stimuli on diagnostic methods is therefore important. Lower body negative pressure (LBNP) and cold pressor test (CPT) are experimental models of central hypovolemia and pain, respectively. In the present analysis, we explored the effects of LBNP and CPT on pre‐ejection period and pulse transit time, aiming to further elucidate the potential use of these variables in diagnosing hypovolemia in trauma patients. We exposed healthy volunteers to four experimental sequences with hypovolemia (LBNP 60 mmHg) or normovolemia (LBNP 0 mmHg) and pain (CPT) or no pain (sham) in a 2 × 2 fashion. We calculated pre‐ejection period and pulse transit time from ECG and ascending aortic blood velocity (suprasternal Doppler) and continuous noninvasive arterial pressure waveform (volume‐clamp method). Fourteen subjects were available for the current analyses. This experimental study found that pre‐ejection period increased with hypovolemia and remained unaltered with pain. Pulse transit time was reduced by pain and increased with hypovolemia. Thus, the direction of change in pulse transit time has the potential to distinguish hypovolemia and pain. [ABSTRACT FROM AUTHOR]

Abstract Background Individuals with autism spectrum disorder (ASD) often experience elevated stress during social interactions and may have difficulty forming and maintaining peer relationships. The autonomic nervous system (ANS) directs physiological changes in the body in response to a number of environmental stimuli, including social encounters. Evidence suggests the flexibility of the ANS response is an important driving factor in shaping social behavior. For youth with ASD, increased stress response and/or atypical ANS regulation to benign social encounters may therefore influence social behaviors, and, along with developmental and experiential factors, shape psychological outcomes. Methods The current study measured ANS response to a peer-based social interaction paradigm in 50 typically developing (TD) children and 50 children with ASD (ages 10–13). Respiratory sinus arrhythmia (RSA), a cardiac measure of parasympathetic influence on the heart, and pre-ejection period (PEP), a sympathetic indicator, were collected. Participants engaged in a friendly, face-to-face conversation with a novel, same-aged peer, and physiological data were collected continuously before and during the interaction. Participants also reported on state anxiety following the interaction, while parents reported on the child’s social functioning and number of social difficulties. Results Linear mixed models revealed that, while there were no diagnostic effects for RSA or PEP, older youth with ASD appeared to demonstrate a blunted parasympathetic (RSA) response. Further, increased severity of parent-reported social symptoms was associated with lower RSA. Youth with ASD reported more anxiety following the interaction; however, symptoms were not related to RSA or PEP response based on linear mixed modeling. Conclusions Physiological regulation, age, and social functioning likely influence stress responses to peer interactions for youth with ASD. Parasympathetic functioning, as opposed to sympathetic arousal, may be especially important in behavioral regulation, as older youth with ASD demonstrated atypical regulation and response to the social interaction paradigm. Future studies should help to further elucidate the developmental factors contributing to stress responses in ASD, the impact of physiological response on observable social behavior, and potential long-term consequences of chronic social stress in youth with ASD.

Abstract Trauma patients may suffer significant blood loss, and noninvasive methods to diagnose hypovolemia in these patients are needed. Physiologic effects of hypovolemia, aiming to maintain blood pressure, are largely mediated by increased sympathetic nervous activity. Trauma patients may however experience pain, which also increases sympathetic nervous activity, potentially confounding measures of hypovolemia. Elucidating the common and separate effects of the two stimuli on diagnostic methods is therefore important. Lower body negative pressure (LBNP) and cold pressor test (CPT) are experimental models of central hypovolemia and pain, respectively. In the present analysis, we explored the effects of LBNP and CPT on pre‐ejection period and pulse transit time, aiming to further elucidate the potential use of these variables in diagnosing hypovolemia in trauma patients. We exposed healthy volunteers to four experimental sequences with hypovolemia (LBNP 60 mmHg) or normovolemia (LBNP 0 mmHg) and pain (CPT) or no pain (sham) in a 2 × 2 fashion. We calculated pre‐ejection period and pulse transit time from ECG and ascending aortic blood velocity (suprasternal Doppler) and continuous noninvasive arterial pressure waveform (volume‐clamp method). Fourteen subjects were available for the current analyses. This experimental study found that pre‐ejection period increased with hypovolemia and remained unaltered with pain. Pulse transit time was reduced by pain and increased with hypovolemia. Thus, the direction of change in pulse transit time has the potential to distinguish hypovolemia and pain.

Forcecardiography (FCG) is a novel technique that measures the local forces induced on the chest wall by the mechanical activity of the heart. Specific piezoresistive or piezoelectric force sensors are placed on subjects' thorax to measure these very small forces. The FCG signal can be divided into three components: low-frequency FCG, high-frequency FCG (HF-FCG) and heart sound FCG. HF-FCG has been shown to share a high similarity with the Seismocardiogram (SCG), which is commonly acquired via small accelerometers and is mainly used to locate specific fiducial markers corresponding to essential events of the cardiac cycle (e.g., heart valves opening and closure, peaks of blood flow). However, HF-FCG has not yet been demonstrated to provide the timings of these markers with reasonable accuracy. This study addresses the detection of the aortic valve opening (AO) marker in FCG signals. To this aim, simultaneous recordings from FCG and SCG sensors were acquired, together with Electrocardiogram (ECG) recordings, from a few healthy subjects at rest, both during quiet breathing and apnea. The AO markers were located in both SCG and FCG signals to obtain pre-ejection periods (PEP) estimates, which were compared via statistical analyses. The PEPs estimated from FCG and SCG showed a strong linear relationship (r > 0.95) with a practically unit slope, and 95% of their differences were found to be distributed within ± 4.6 ms around small biases of approximately 1 ms, corresponding to percentage differences lower than 5% of the mean measured PEP. These preliminary results suggest that FCG can provide accurate AO timings and PEP estimates. [ABSTRACT FROM AUTHOR]

Measuring electrodermal activity (EDA) on the wrist with the use of dry electrodes is a promising method to help identify person-specific stressors during prolonged recordings in daily life. While the feasibility of this method has been demonstrated, detailed testing of validity of such ambulatory EDA is scarce. In a controlled laboratory study, we examine SCL and ns.SCR derived from wrist-based dry electrodes (Philips DTI) and palm-based wet electrodes (VU-AMS) in 112 healthy adults (57% females, mean age = 22.3, SD = 3.4) across 26 different conditions involving mental stressors or physical activities. Changes in these EDA measures were compared to changes in the Pre-ejection period (PEP) and stressor-induced changes in affect. Absolute SCL and ns.SCR frequency were lower at the wrist compared to the palm. Wrist-based ns.SCR and palm-based ns.SCR and SCL responded directionally consistent with our experimental manipulation of sympathetic nervous system (SNS) activity. Average within-subject correlations between palm-based and wrist-based EDA were significant but modest (r SCL = 0.31; r ns.SCR = 0.42). Changes in ns.SCR frequency at the palm (r = −0.44) and the wrist (r = −0.36) were correlated with changes in PEP. Both palm-based and wrist based EDA predicted changes in affect (6.5%–14.5%). Our data suggest that wrist-based ns.SCR frequency is a useful addition to the psychophysiologist's toolkit, at least for epidemiology-sized ambulatory studies of changes in sympathetic activity during daily life. • Non-specific skin conductance responses are superior to skin conductance level. • Performance of wrist responses in many aspects comparable to palm responses • Could be used in epidemiology-sized studies with prolonged recording for months [ABSTRACT FROM AUTHOR]

BackgroundCardiovascular risk may be increased in astronauts after long term space flights based on biomarkers indicating premature vascular aging. We tested the hypothesis that 60 days of strict 6° head down tilt bed rest (HDTBR), an established space analog, promotes vascular stiffening and that artificial gravity training ameliorates the response.MethodsWe studied 24 healthy participants (8 women, 24–55 years, BMI = 24.3 ± 2.1 kg/m2) before and at the end of 60 days HDTBR. 16 subjects were assigned to daily artificial gravity. We applied echocardiography to measure stroke volume and isovolumetric contraction time (ICT), calculated aortic compliance (stroke volume/aortic pulse pressure), and assessed aortic distensibility by MRI. Furthermore, we measured brachial-femoral pulse wave velocity (bfPWV) and pulse wave arrival times (PAT) in different vascular beds by blood pressure cuffs and photoplethysmography. We corrected PAT for ICT (cPAT).ResultsIn the pooled sample, diastolic blood pressure (+8 ± 7 mmHg, p < 0.001), heart rate (+7 ± 9 bpm, p = 0.002) and ICT (+8 ± 13 ms, p = 0.036) increased during HDTBR. Stroke volume decreased by 14 ± 15 ml (p = 0.001). bfPWV, aortic compliance, aortic distensibility and all cPAT remained unchanged. Aortic area tended to increase (p = 0.05). None of the parameters showed significant interaction between HDTBR and artificial gravity training.Conclusion60 days HDTBR, while producing cardiovascular deconditioning and cephalad fluid shifts akin to weightlessness, did not worsen vascular stiffness. Artificial gravity training did not modulate the response.

Traditionally, impedance derived measures of cardiac autonomic balance (CAB) and regulation (CAR) are calculated using indices of heart rate variability (HRV) that primarily reflect parasympathetic nervous system activity (e.g., high-frequency HRV | HF-HRV) and pre-ejection period (PEP; a systolic time interval and measure of sympathetic activity). However, HF-HRV and PEP are considered measures of chronotropic and inotropic cardiac influence, respectively. Left ventricular ejection time (LVET) is a systolic time interval that reflects sympathetic chronotropic influence, and therefore may be a more appropriate measure for calculating CAB and CAR compared to PEP. Thus, the current study evaluates both PEP and LVET in the calculation of CAB and CAR. Data from 158 healthy participants (mean age = 19.09 years old, SD = 1.84 years) were available for analyses. CAB and CAR values were calculated using both HF-HRV and the root mean square of successive differences, in addition to both PEP and LVET, in accordance with previously established guidelines. Analyses showed that correlations were significantly weaker between CAB and CAR calculated using LVET for both HF (z = 5.12, p < 0.001) and RMSSD (z = 5.26, p < 0.001) than with PEP. These data suggest that LVET, compared to PEP, provides better “autonomic space” as evidenced by a lack of correlation between CAB and CAR computed using LVET. We stress that future research consider calculating CAB and CAR using chronotropic measures for both parasympathetic and sympathetic activity, as doing so may yield more accurate and independent measures of cardiac autonomic activity compared to a mixture of inotropic (i.e., PEP) and chronotropic (i.e., HF-HRV) measures.

Objective: Local oscillation of the chest wall in response to events during the cardiac cycle may be captured using a sensing modality called seismocardiography (SCG), which is commonly used to infer cardiac time intervals (CTIs) such as the pre-ejection period (PEP). An important factor impeding the ubiquitous application of SCG for cardiac monitoring is that morphological variability of the signals makes consistent inference of CTIs a difficult task in the time-domain. The goal of this work is therefore to enable SCG-based physiological monitoring during trauma-induced hemorrhage using signal dynamics rather than morphological features. Methods: We introduce and explore the observation that SCG signals follow a consistent low-dimensional manifold structure during periods of changing PEP induced in a porcine model of trauma injury. Furthermore, we show that the distance traveled along this manifold correlates strongly to changes in PEP (Δ PEP). Results: Δ PEP estimation during hemorrhage was achieved with a median R2 of 92.5% using a rapid manifold approximation method, comparable to an ISOMAP reference standard, which achieved an R2 of 95.3%. Conclusion: Rapidly approximating the manifold structure of SCG signals allows for physiological inference abstracted from the time-domain, laying the groundwork for robust, morphology-independent processing methods. Significance: Ultimately, this work represents an important advancement in SCG processing, enabling future clinical tools for trauma injury management. [ABSTRACT FROM AUTHOR]

Background: Cardiovascular risk may be increased in astronauts after long term space flights based on biomarkers indicating premature vascular aging. We tested the hypothesis that 60 days of strict 6° head down tilt bed rest (HDTBR), an established space analog, promotes vascular stiffening and that artificial gravity training ameliorates the response. Methods: We studied 24 healthy participants (8 women, 24–55 years, BMI = 24.3 ± 2.1 kg/m2) before and at the end of 60 days HDTBR. 16 subjects were assigned to daily artificial gravity. We applied echocardiography to measure stroke volume and isovolumetric contraction time (ICT), calculated aortic compliance (stroke volume/aortic pulse pressure), and assessed aortic distensibility by MRI. Furthermore, we measured brachial-femoral pulse wave velocity (bfPWV) and pulse wave arrival times (PAT) in different vascular beds by blood pressure cuffs and photoplethysmography. We corrected PAT for ICT (cPAT). Results: In the pooled sample, diastolic blood pressure (+8 ± 7 mmHg, p < 0.001), heart rate (+7 ± 9 bpm, p = 0.002) and ICT (+8 ± 13 ms, p = 0.036) increased during HDTBR. Stroke volume decreased by 14 ± 15 ml (p = 0.001). bfPWV, aortic compliance, aortic distensibility and all cPAT remained unchanged. Aortic area tended to increase (p = 0.05). None of the parameters showed significant interaction between HDTBR and artificial gravity training. Conclusion: 60 days HDTBR, while producing cardiovascular deconditioning and cephalad fluid shifts akin to weightlessness, did not worsen vascular stiffness. Artificial gravity training did not modulate the response. [ABSTRACT FROM AUTHOR]

Traditionally, impedance derived measures of cardiac autonomic balance (CAB) and regulation (CAR) are calculated using indices of heart rate variability (HRV) that primarily reflect parasympathetic nervous system activity (e.g., high-frequency HRV | HF-HRV) and pre-ejection period (PEP; a systolic time interval and measure of sympathetic activity). However, HF-HRV and PEP are considered measures of chronotropic and inotropic cardiac influence, respectively. Left ventricular ejection time (LVET) is a systolic time interval that reflects sympathetic chronotropic influence, and therefore may be a more appropriate measure for calculating CAB and CAR compared to PEP. Thus, the current study evaluates both PEP and LVET in the calculation of CAB and CAR. Data from 158 healthy participants (mean age = 19.09 years old, SD = 1.84 years) were available for analyses. CAB and CAR values were calculated using both HF-HRV and the root mean square of successive differences, in addition to both PEP and LVET, in accordance with previously established guidelines. Analyses showed that correlations were significantly weaker between CAB and CAR calculated using LVET for both HF (z = 5.12, p < 0.001) and RMSSD (z = 5.26, p < 0.001) than with PEP. These data suggest that LVET, compared to PEP, provides better "autonomic space" as evidenced by a lack of correlation between CAB and CAR computed using LVET. We stress that future research consider calculating CAB and CAR using chronotropic measures for both parasympathetic and sympathetic activity, as doing so may yield more accurate and independent measures of cardiac autonomic activity compared to a mixture of inotropic (i.e., PEP) and chronotropic (i.e., HF-HRV) measures. [ABSTRACT FROM AUTHOR]

Autonomic nervous system (ANS) activity is a core and central component of emotion and motivated action. The myriad social and cognitive challenges faced by humans require flexible modulation of ANS activity for different contexts. In this study, simultaneous activity of the parasympathetic and sympathetic nervous system was measured using respiratory sinus arrhythmia (RSA) and pre-ejection period (PEP), respectively. Samples combined four previous studies (N = 325, 63% female, aged 15–55) in which RSA and PEP were collected continuously during a resting baseline and an acute stressor, the Trier Social Stress Task. The concurrent relation between RSA and PEP responses was modelled in order to determine the extent to which SNS and PNS activity is correlated across the task within and between participants, and whether this correlation was moderated by age, race, sex, or baseline RSA and PEP. Overall, RSA and PEP were reciprocally coupled. However, recovery from a stressor was characterized by coactivation. Individuals also vary in the extent to which their SNS and PNS are reciprocally coupled; women, younger adults, and individuals with higher baseline RSA showed more reciprocal coupling than men, older adults, and those with lower baseline RSA, respectively, reflecting greater coordination of physiological responding in the former groups. • Correlated activity of the sympathetic and parasympathetic nervous systems was measured during the Trier Social Stress Task. • Changes in respiratory sinus arrhythmia (RSA) and pre-ejection period (PEP) indicated reciprocal activity, overall. • Recovery from a stressor was characterized by coactivation. • Correlations of RSA and PEP were stronger in females than males, and among older adults and those with higher baseline RSA. [ABSTRACT FROM AUTHOR]

Anxiety is characterized by low confidence in daily decisions, coupled with high levels of phenomenological stress. Ventromedial prefrontal cortex (vmPFC) plays an integral role in maladaptive anxious behaviors via decreased sensitivity to threatening vs. non-threatening stimuli (fear generalization). vmPFC is also a key node in approach-avoidance decision making requiring two-dimensional integration of rewards and costs. More recently, vmPFC has been implicated as a key cortical input to the sympathetic branch of the autonomic nervous system. However, little is known about the role of this brain region in mediating rapid stress responses elicited by changes in confidence during decision making. We used an approach-avoidance task to examine the relationship between sympathetically mediated cardiac stress responses, vmPFC activity and choice behavior over long and short time-scales. To do this, we collected concurrent fMRI, EKG and impedance cardiography recordings of sympathetic drive while participants made approach-avoidance decisions about monetary rewards paired with painful electric shock stimuli. We observe first that increased sympathetic drive (shorter pre-ejection period) in states lasting minutes are associated with choices involving reduced decision ambivalence. Thus, on this slow time scale, sympathetic drive serves as a proxy for “mobilization” whereby participants are more likely to show consistent value-action mapping. In parallel, imaging analyses reveal that on shorter time scales (estimated with a trial-to-trial GLM), increased vmPFC activity, particularly during low-ambivalence decisions, is associated with decreased sympathetic state. Our findings support a role of sympathetic drive in resolving decision ambivalence across long time horizons and suggest a potential role of vmPFC in modulating this response on a moment-to-moment basis.

Research on effort and motivation commonly assesses how the sympathetic branch of the autonomic nervous system affects the cardiovascular system. The cardiac pre-ejection period (PEP), assessed via impedance cardiography, is a common outcome, but assessing PEP requires identifying subtle points on cardiac waveforms. The present research examined the psychometric value of the RZ interval (RZ), which has recently been proposed as an indicator of sympathetic activity, for effort research. Also known as the initial systolic time interval (ISTI), RZ is the time (in ms) between the ECG R peak and the dZ/dt Z peak. Unlike PEP, RZ involves salient waveform points that are easily and reliably identified. Data from two experiments evaluated the suitability of RZ for effort paradigms and compared it to a popular automated PEP method. In Studies 1 (n = 89) and 2 (n = 71), participants completed a standard appetitive task in which each correct response earned a small amount of cash. As expected, incentives significantly affected PEP and RZ in both experiments. PEP and RZ were highly correlated (all rs ≥ 0.89), and RZ consistently yielded a larger effect size than PEP. In Study 3, a quantitative synthesis of the experiments indicated that the effect size of RZ's response to incentives (Hedges's g = 0.432 [0.310, 0.554]) was roughly 15% larger than PEP's effect size (g = 0.376 [0.256, 0.496]). RZ thus appears promising for future research on sympathetic aspects of effort-related cardiac activity. [ABSTRACT FROM AUTHOR]

Anxiety is characterized by low confidence in daily decisions, coupled with high levels of phenomenological stress. Ventromedial prefrontal cortex (vmPFC) plays an integral role in maladaptive anxious behaviors via decreased sensitivity to threatening vs. non-threatening stimuli (fear generalization). vmPFC is also a key node in approach-avoidance decision making requiring two-dimensional integration of rewards and costs. More recently, vmPFC has been implicated as a key cortical input to the sympathetic branch of the autonomic nervous system. However, little is known about the role of this brain region in mediating rapid stress responses elicited by changes in confidence during decision making. We used an approach-avoidance task to examine the relationship between sympathetically mediated cardiac stress responses, vmPFC activity and choice behavior over long and short time-scales. To do this, we collected concurrent fMRI, EKG and impedance cardiography recordings of sympathetic drive while participants made approach-avoidance decisions about monetary rewards paired with painful electric shock stimuli. We observe first that increased sympathetic drive (shorter pre-ejection period) in states lasting minutes are associated with choices involving reduced decision ambivalence. Thus, on this slow time scale, sympathetic drive serves as a proxy for "mobilization" whereby participants are more likely to show consistent value-action mapping. In parallel, imaging analyses reveal that on shorter time scales (estimated with a trial-to-trial GLM), increased vmPFC activity, particularly during low-ambivalence decisions, is associated with decreased sympathetic state. Our findings support a role of sympathetic drive in resolving decision ambivalence across long time horizons and suggest a potential role of vmPFC in modulating this response on a moment-to-moment basis. [ABSTRACT FROM AUTHOR]

The goals of this research were to analyze cardiac sympathetic recovery patterns and evaluate whether sympathetic cardiac responses to a task challenge can be predicted using residual cardiac activity measured directly after the task (that is, during the recovery period). In two studies (total N = 181), we measured cardiac sympathetic activity, quantified as pre‐ejection period and RB interval, during both task performance and the 2‐min recovery period following the task. Additional analyses examined effects on the RZ interval. We found that sympathetic recovery from a task was rather quick: Cardiovascular recovery occurred within the first 30 s of the recovery period. Nevertheless, residual cardiac activity during the recovery period had predictive power for task‐related cardiac activity. This suggests that sympathetic cardiac activity during recovery may serve as a useful indicator of task‐related cardiac sympathetic activity. We discuss the implications of these findings for practical applications and the design of future studies. There are multiple scenarios in which it is very difficult or even impossible to reliably assess sympathetic cardiac activity. This is because measures of heart contractility, such as the pre‐ejection period (PEP), RB, and RZ‐interval, are prone to signal distortion and artifacts. We found existing methods to deal with this problem insufficient and in the current paper we propose to focus on the post‐task activity as a proxy of cardiac sympathetic activity during task performance when recording impedance cardiography during a task is impossible. Furthermore, the current paper describes the patterns of cardiac sympathetic recovery for the PEP, RB, and RZ intervals, largely neglected in the recovery literature. [ABSTRACT FROM AUTHOR]

Background: Individuals with autism spectrum disorder (ASD) often experience elevated stress during social interactions and may have difficulty forming and maintaining peer relationships. The autonomic nervous system (ANS) directs physiological changes in the body in response to a number of environmental stimuli, including social encounters. Evidence suggests the flexibility of the ANS response is an important driving factor in shaping social behavior. For youth with ASD, increased stress response and/or atypical ANS regulation to benign social encounters may therefore influence social behaviors, and, along with developmental and experiential factors, shape psychological outcomes. Methods: The current study measured ANS response to a peer-based social interaction paradigm in 50 typically developing (TD) children and 50 children with ASD (ages 10–13). Respiratory sinus arrhythmia (RSA), a cardiac measure of parasympathetic influence on the heart, and pre-ejection period (PEP), a sympathetic indicator, were collected. Participants engaged in a friendly, face-to-face conversation with a novel, same-aged peer, and physiological data were collected continuously before and during the interaction. Participants also reported on state anxiety following the interaction, while parents reported on the child's social functioning and number of social difficulties. Results: Linear mixed models revealed that, while there were no diagnostic effects for RSA or PEP, older youth with ASD appeared to demonstrate a blunted parasympathetic (RSA) response. Further, increased severity of parent-reported social symptoms was associated with lower RSA. Youth with ASD reported more anxiety following the interaction; however, symptoms were not related to RSA or PEP response based on linear mixed modeling. Conclusions: Physiological regulation, age, and social functioning likely influence stress responses to peer interactions for youth with ASD. Parasympathetic functioning, as opposed to sympathetic arousal, may be especially important in behavioral regulation, as older youth with ASD demonstrated atypical regulation and response to the social interaction paradigm. Future studies should help to further elucidate the developmental factors contributing to stress responses in ASD, the impact of physiological response on observable social behavior, and potential long-term consequences of chronic social stress in youth with ASD. [ABSTRACT FROM AUTHOR]

Previous research has suggested reduced parasympathetic cardiac regulation during cognitive activity in major depressive disorder (MDD). However, little is known about possible abnormalities in sympathetic control and cardiovascular reactivity. This study aimed to provide a comprehensive analysis of autonomic cardiovascular control in the context of executive functions in MDD. Thirty six MDD patients and 39 healthy controls participated. Parameters of sympathetic (pre‐ejection period, PEP) and parasympathetic control (high and low frequency heart rate variability, HF HRV, LF HRV; and baroreflex sensitivity, BRS) as well as RR interval were obtained at rest and during performance of executive function tasks (number‐letter task, n‐back task, continuous performance test, and Stroop task). Patients, as compared to controls, exhibited lower HF HRV and LF HRV during task execution and smaller shortenings in PEP and RR interval between baseline and tasks. They displayed longer reaction times during all conditions of the tasks and more omission errors and false alarms on the continuous performance test. In the total sample, on‐task HF HRV, LF HRV and BRS, and reactivity in HF HRV, LF HRV, and PEP, were positively associated with task performance. As performance reduction arose independent of executive function load of the tasks, the behavioral results reflect impairments in attention and processing speed rather than executive dysfunctions in MDD. Abnormalities in cardiovascular control during cognition in MDD appear to involve both divisions of the autonomic nervous system. Low tonic parasympathetic control and blunted sympathetic reactivity imply reduced physiological adjustment resources and, by extension, provide suboptimal conditions for cognitive performance. This study investigated autonomic cardiovascular control during cognitive activity in MDD. In addition to impaired cognitive performance, patients showed reduced HRV, smaller decreases in pre‐ejection period and RR interval during task execution. On‐task HRV and reactivity in HRV, baroreflex sensitivity, and pre‐ejection period correlated positively with task performance. The study, for the first time, documented that that low tonic parasympathetic control and blunted sympathetic reactivity characterizing MDD may provide suboptimal conditions for cognitive performance. [ABSTRACT FROM AUTHOR]

Pre-professional and professional dancers (n = 60) participated in this ambulatory psychophysiology study that investigated performance flow and heart rate and autonomic nervous system (ANS) function during three time periods: baseline rest, performance, and post-performance rest. To gather these results, the psychophysiology laboratory traveled to the concert hall to collect data on dancers. The self-report Flow State Scale (FSS) measured global flow, challenge–skill balance, sense of control, and autotelic experiences; it addresses important features of the creative experience of performing artists. These data were collected immediately following the performance. The flow measures were compared with physiologic responses to performance [heart rate, pre-ejection period (PEP), root mean square differences of successive R-R (heartbeat) intervals (RMSSD), cardiac autonomic balance, and cardiac autonomic regulation]. The regression analyses indicated that greater sympathetic nervous system (SNS) activation with performance (PEP change from base to performance) explained 8.8% of the variance in sense of control, whereas less cardiac autonomic regulation explained 13.8% of the variance in autotelic experiences. The sample was then divided into high and low flow groupings and four autonomic groups. During performance, the high autotelic group and high sense of control group had a higher distribution of dancers with co-inhibition of both ANS branches than had the low autotelic and sense of control groups who employed more co-activation of both ANS branches (chi-square analyses). These novel findings add to the growing information about the interaction of both branches of the ANS during creative performance flow states.

Forcecardiography (FCG) is a novel technique that measures the local forces induced on the chest wall by the mechanical activity of the heart. Specific piezoresistive or piezoelectric force sensors are placed on subjects’ thorax to measure these very small forces. The FCG signal can be divided into three components: low-frequency FCG, high-frequency FCG (HF-FCG) and heart sound FCG. HF-FCG has been shown to share a high similarity with the Seismocardiogram (SCG), which is commonly acquired via small accelerometers and is mainly used to locate specific fiducial markers corresponding to essential events of the cardiac cycle (e.g., heart valves opening and closure, peaks of blood flow). However, HF-FCG has not yet been demonstrated to provide the timings of these markers with reasonable accuracy. This study addresses the detection of the aortic valve opening (AO) marker in FCG signals. To this aim, simultaneous recordings from FCG and SCG sensors were acquired, together with Electrocardiogram (ECG) recordings, from a few healthy subjects at rest, both during quiet breathing and apnea. The AO markers were located in both SCG and FCG signals to obtain pre-ejection periods (PEP) estimates, which were compared via statistical analyses. The PEPs estimated from FCG and SCG showed a strong linear relationship (r > 0.95) with a practically unit slope, and 95% of their differences were found to be distributed within ± 4.6 ms around small biases of approximately 1 ms, corresponding to percentage differences lower than 5% of the mean measured PEP. These preliminary results suggest that FCG can provide accurate AO timings and PEP estimates.

Abstract Background Non-invasive continuous blood pressure monitors are of great interest to the medical community due to their value in hypertension management. Recently, studies have shown the potential of pulse pressure as a therapeutic target for hypertension, but not enough attention has been given to non-invasive continuous monitoring of pulse pressure. Although accurate pulse pressure estimation can be of direct value to hypertension management and indirectly to the estimation of systolic blood pressure, as it is the sum of pulse pressure and diastolic blood pressure, only a few inadequate methods of pulse pressure estimation have been proposed. Methods We present a novel, non-invasive blood pressure and pulse pressure estimation method based on pulse transit time and pre-ejection period. Pre-ejection period and pulse transit time were measured non-invasively using electrocardiogram, seismocardiogram, and photoplethysmogram measured from the torso. The proposed method used the 2-element Windkessel model to model pulse pressure with the ratio of stroke volume, approximated by pre-ejection period, and arterial compliance, estimated by pulse transit time. Diastolic blood pressure was estimated using pulse transit time, and systolic blood pressure was estimated as the sum of the two estimates. The estimation method was verified in 11 subjects in two separate conditions with induced cardiovascular response and the results were compared against a reference measurement and values obtained from a previously proposed method. Results The proposed method yielded high agreement with the reference (pulse pressure correlation with reference R ≥ 0.927, diastolic blood pressure correlation with reference R ≥ 0.854, systolic blood pressure correlation with reference R ≥ 0.914) and high estimation accuracy in pulse pressure (mean root-mean-squared error ≤ 3.46 mmHg) and blood pressure (mean root-mean-squared error ≤ 6.31 mmHg for diastolic blood pressure and ≤ 8.41 mmHg for systolic blood pressure) over a wide range of hemodynamic changes. Conclusion The proposed pulse pressure estimation method provides accurate estimates in situations with and without significant changes in stroke volume. The proposed method improves upon the currently available systolic blood pressure estimation methods by providing accurate pulse pressure estimates.

There has been a longstanding debate about the link between callous-unemotional traits and fearlessness. However, biological evidence for a relationship in adolescents is lacking. Using two adolescent samples, we measured emotional reactivity and cardiac measures of sympathetic (pre-ejection period) and parasympathetic (respiratory sinus arrhythmia) reactivity during 3D TV and virtual reality fear induction. Study 1 included 62 community adolescents from a stratified sample. Study 2 included 60 adolescents from Emotional and Behavioral Difficulties schools. Results were consistent across both studies. Adolescents with high callous-unemotional traits showed coactivation of the sympathetic and parasympathetic nervous system. Consistent with these results, youths with callous-unemotional traits self-reported that they felt more in control after the fear induction. Thus, in both samples, youth with callous-unemotional traits displayed a physiological and emotional profile suggesting they maintained control during fear induction. Therefore, it is proposed here that a shift in thinking of youth with callous-unemotional traits as fearless to youth with callous-unemotional traits are better able to manage fearful situations, may be more appropriate. [ABSTRACT FROM AUTHOR]

Pre-professional and professional dancers (n = 60) participated in this ambulatory psychophysiology study that investigated performance flow and heart rate and autonomic nervous system (ANS) function during three time periods: baseline rest, performance, and post-performance rest. To gather these results, the psychophysiology laboratory traveled to the concert hall to collect data on dancers. The self-report Flow State Scale (FSS) measured global flow, challenge–skill balance, sense of control, and autotelic experiences; it addresses important features of the creative experience of performing artists. These data were collected immediately following the performance. The flow measures were compared with physiologic responses to performance [heart rate, pre-ejection period (PEP), root mean square differences of successive R-R (heartbeat) intervals (RMSSD), cardiac autonomic balance, and cardiac autonomic regulation]. The regression analyses indicated that greater sympathetic nervous system (SNS) activation with performance (PEP change from base to performance) explained 8.8% of the variance in sense of control, whereas less cardiac autonomic regulation explained 13.8% of the variance in autotelic experiences. The sample was then divided into high and low flow groupings and four autonomic groups. During performance, the high autotelic group and high sense of control group had a higher distribution of dancers with co-inhibition of both ANS branches than had the low autotelic and sense of control groups who employed more co-activation of both ANS branches (chi-square analyses). These novel findings add to the growing information about the interaction of both branches of the ANS during creative performance flow states. [ABSTRACT FROM AUTHOR]

Although emotional responses are theorized to be important in the development of empathy, findings regarding the prediction of early empathic behavior by infant behavioral and physiological responses are mixed. This study examined whether behavioral and physiological responses to mild emotional challenge (still face paradigm and car seat task) in 118 infants at age 6 months predicted empathic distress and empathic concern in response to an empathy‐evoking task (i.e, experimenter's distress simulation) at age 20 months. Correlation analyses, corrected for sex and baseline levels of physiological arousal, showed that stronger physiological and behavioral responses to emotional challenge at age 6 months were positively related to observed empathic distress, but not empathic concern, at age 20 months. Linear regression analyses indicated that physiological and behavioral responses to challenge at 6 months independently predicted empathic distress at 20 months, which suggests an important role for both physiological and behavioral emotional responses in empathy development. In addition, curvilinear regression analyses showed quadratic associations between behavioral responses at 6 months, and empathic distress and empathic concern at 20 months, which indicates that moderate levels of behavioral responsivity predict the highest levels of empathic distress and empathic concern. [ABSTRACT FROM AUTHOR]

Flow activities (e.g. sports and gaming) have been associated with positive affect and prolonged engagement. In the gambling field, modern electronic gaming machines (EGMs, including modern slot machines) have drawn concern as a potentially flow-inducing activity that may be associated with gambling-related harms. Current research has heavily relied on self-reported flow, and further insights may be afforded by physiological methods. We present data from three separate experiments in which self-reported gambling flow and cardiac pre-ejection period (PEP; a measure of sympathetic nervous system arousal) were examined. Male undergraduate participants gambled on a genuine EGM in a laboratory setting for a period of at least 15 min, and completed the Flow subscale of the game experience questionnaire (GEQ). Aggregated data were analyzed using multilevel regression. Although EGM gambling was not associated with significant changes in PEP across participants, we found that self-reported flow states were associated with significant decreases in PEP during the first five minutes of EGM use. Thus, participants who experienced flow showed a greater sympathetic nervous system response to the onset of gambling. Though these effects were consistent in experiments 1 and 2, in experiment 3 the effect was inverted during the same time window. We conclude that flow during EGM gambling appears to be associated with early changes in sympathetic nervous system activity, but stress that more research is needed to characterize boundary conditions and moderating factors. [ABSTRACT FROM AUTHOR]

Research on the Implicit-Affect-Primes-Effort model (Gendolla, 2012) found that priming happiness or anger in challenging tasks results in stronger sympathetically mediated cardiovascular responses, reflecting effort, than priming sadness or fear. Recent studies on action shielding revealed that personal task choice can attenuate affective influences on action execution (e.g., Gendolla et al., 2021). The present experiment tested if this action shielding effect also applies to affect primes' influences on cardiovascular response. Participants (N = 136) worked on a cognitive task with integrated briefly flashed and backward masked facial expressions of sadness vs. happiness. Half of the participants could ostensibly choose whether they wanted to work on an attention or on a memory task, while the other half was assigned to one task. Our findings revealed effects on cardiac pre-ejection period (PEP), which align with the expected outcomes for a task of unfixed difficulty where participants establish their own performance standard. Most importantly, task choice shielded against the implicit affective influence on PEP that was evident when the task was externally assigned. Effects on systolic blood pressure (SBP) reactivity largely corresponded to those of PEP. • Participants could choose or were assigned to a cognitive task. • Briefly flashed happiness vs. sadness primes were presented during the task. • When the task was assigned, sadness primes led to stronger cardiac PEP reactivity than happiness primes. • This priming effect was no longer observed when participants could personally choose their task. [ABSTRACT FROM AUTHOR]

Abstract Introduction Building on prior evidence that prosocial behavior is related to the regulation of personal distress in difficult situations, and given that physiological regulation is a central contributor to effective emotion regulation, this investigation evaluated whether and how children's autonomic nervous system (ANS) reactivity during emotion challenges influenced later expressions of prosocial behavior. Methods The current study utilized a diverse sample of school‐aged children (N = 169; 47.9% female; 47.3% Latinx) to evaluate relations between children's parasympathetic (i.e., respiratory sinus arrhythmia; RSA) and sympathetic (i.e., pre‐ejection period; PEP) reactivity in response to each of three film‐elicited emotion challenges (i.e., sadness, happiness, and fear) at age 7 and both observed and parent‐reported prosocial behavior one year later. Results Children's parasympathetic reactivity to a film eliciting sadness evidenced a nonlinear relation with later prosocial sharing such that children who evidenced either RSA withdrawal or augmentation in response to the sad emotion challenge engaged in higher levels of prosocial behavior than children who evidenced relatively low or absent reactivity. Parasympathetic reactivity to films eliciting happiness or fear was not significantly related to later prosocial behavior. Likewise, children's sympathetic reactivity in response to the emotion challenges did not significantly predict later prosocial behavior. Conclusions These findings provide preliminary support for a nonlinear association between children's parasympathetic emotion reactivity and later prosocial behavior, and suggest that children's ANS regulation in sad emotion contexts may be particularly important for understanding prosocial development.