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The neurovisceral integration model proposes that information flows bidirectionally between the brain and the heart via the vagus nerve, indexed by vagally mediated heart rate variability (vmHRV). Voluntary reduction in breathing rate (slow‐paced breathing, SPB, 5.5 Breathing Per Minute (BPM)) can enhance vmHRV. Additionally, prefrontal transcranial direct current stimulation (tDCS) can modulate the excitability of the prefrontal region and influence the vagus nerve. However, research on the combination of SPB and prefrontal tDCS to increase vmHRV and other cardiac (heart rate (HR) and blood pressure) and peripheral (skin conductance) indices is scarce. We hypothesized that the combination of 20 min of SPB and prefrontal tDCS would have a greater effect than each intervention in isolation. Hence, 200 participants were divided into four groups: active tDCS with SPB, active tDCS with 15 BPM breathing, sham tDCS with SPB, and sham tDCS with 15 BPM breathing. Regardless of the tDCS condition, the 5.5 BPM group showed a significant increase in vmHRV over 20 minutes and significant decreases in HR at the first and second 5‐min epochs of the intervention. Regardless of breathing condition, the active tDCS group exhibited higher HR at the fourth 5‐min epoch of the intervention than the sham tDCS group. No other effects were observed. Overall, SPB is a robust technique for increasing vmHRV, whereas prefrontal tDCS may produce effects that counteract those of SPB. More research is necessary to test whether and how SPB and neuromodulation approaches can be combined to improve cardiac vagal tone. This study explored, for the first time, the temporal course of physical (slow‐paced breathing, SPB) and neuromodulation (prefrontal tDCS) interventions to enhance cardiac vagal tone. Through a well‐sampled between‐subjects sham‐controlled design, this study found that SPB has a very rapid impact on increasing vagally mediated HRV and decreasing HR and blood pressure. Prefrontal tDCS, on the contrary, has a slower effect, mainly increasing heart rate suggesting more sympathetic arousal. Unexpectedly, the combination did not yield beneficial results. [ABSTRACT FROM AUTHOR]

The perception of signals from within the body, known as interoception, is increasingly recognized as a prerequisite for physical and mental health. This study is dedicated to the development of effective technological approaches for enhancing interoceptive abilities. We provide evidence of the effectiveness and practical feasibility of a novel real‐time haptic heartbeat supplementation technology combining principles of biofeedback and sensory augmentation. In a randomized controlled study, we applied the developed naturalistic haptic feedback on a group of 30 adults, while another group of 30 adults received more traditional real‐time visual heartbeat feedback. A single session of haptic, but not visual heartbeat feedback resulted in increased interoceptive accuracy and confidence, as measured by the heart rate discrimination task, and in a shift of attention toward the body. Participants rated the developed technology as more helpful and pleasant than the visual feedback, thus indicating high user satisfaction. The study highlights the importance of matching sensory characteristics of the feedback provided to the natural bodily prototype. Our work suggests that real‐time haptic feedback might be a superior approach for strengthening the mind–body connection in interventions for physical and mental health. In the study, we evaluate the efficacy of a newly developed interoceptive training—supplementation of heartbeat sensations through real‐time haptic feedback. We revealed that the haptic feedback technology improves interoceptive accuracy, increases confidence, and shifts attention toward bodily sensations more effectively than the traditional visual feedback approach, opening new possibilities for clinical and neurowellness applications. [ABSTRACT FROM AUTHOR]

Resting heart rate may confer risk for cardiovascular disease (CVD) and other adverse cardiovascular events. While the brainstem's autonomic control over heart rate is well established, less is known about the regulatory role of higher level cortical and subcortical brain regions, especially in humans. This study sought to characterize the brain networks that predict variation in prevailing heart rate in otherwise healthy adults. We used machine learning approaches designed for complex, high‐dimensional data sets, to predict variation in instantaneous heart period (the inter‐heartbeat‐interval) from whole‐brain hemodynamic signals measured by fMRI. Task‐based and resting‐state fMRI, as well as peripheral physiological recordings, were taken from two data sets that included extensive repeated measurements within individuals. Our models reliably predicted instantaneous heart period from whole‐brain fMRI data both within and across individuals, with prediction accuracies being highest when measured within‐participants. We found that a network of cortical and subcortical brain regions, many linked to visceral motor and visceral sensory processes, were reliable predictors of variation in heart period. This adds to evidence on brain–heart interactions and constitutes an incremental step toward developing clinically applicable biomarkers of brain contributions to CVD risk. Using whole‐brain fMRI data, we reliably predicted instantaneous heart period within and across individuals from the activity of a network of cortical and subcortical brain regions, many linked to visceral motor and visceral sensory processes. This adds to existing evidence on brain–heart interactions and constitutes a step toward developing clinically applicable biomarkers of brain contributions to CVD risk. [ABSTRACT FROM AUTHOR]

The subjective experience of emotions is linked to the contextualized perception and appraisal of changes in bodily (e.g., heart) activity. Increased emotional arousal has been related to attenuated high‐frequency heart rate variability (HF‐HRV), lower EEG parieto‐occipital alpha power, and higher heartbeat‐evoked potential (HEP) amplitudes. We studied emotional arousal‐related brain–heart interactions using immersive virtual reality (VR) for naturalistic yet controlled emotion induction. Twenty‐nine healthy adults (13 women, age: 26 ± 3) completed a VR experience that included rollercoasters while EEG and ECG were recorded. Continuous emotional arousal ratings were collected during a video replay immediately after. We analyzed emotional arousal‐related changes in HF‐HRV as well as in BHIs using HEPs. Additionally, we used the oscillatory information in the ECG and the EEG to model the directional information flows between the brain and heart activity. We found that higher emotional arousal was associated with lower HEP amplitudes in a left fronto‐central electrode cluster. While parasympathetic modulation of the heart (HF‐HRV) and parieto‐occipital EEG alpha power were reduced during higher emotional arousal, there was no evidence for the hypothesized emotional arousal‐related changes in bidirectional information flow between them. Whole‐brain exploratory analyses in additional EEG (delta, theta, alpha, beta and gamma) and HRV (low‐frequency, LF, and HF) frequency bands revealed a temporo‐occipital cluster, in which higher emotional arousal was linked to decreased brain‐to‐heart (i.e., gamma→HF‐HRV) and increased heart‐to‐brain (i.e., LF‐HRV → gamma) information flow. Our results confirm previous findings from less naturalistic experiments and suggest a link between emotional arousal and brain–heart interactions in temporo‐occipital gamma power. [ABSTRACT FROM AUTHOR]

It has been hypothesized that one's ability to control impulses aids in sustaining effort despite experiencing painful physical sensations. Physical exercise has been used extensively as an intervention to strengthen the inhibitory control system and protect an individual's cognitive plan of action. It is unclear, however, whether the high levels of exercise tolerance could facilitate inhibitory control under varied stressors. The present study explored the relationship between subjective exercise tolerance and psychophysiological characteristics that indicate reactivity capacity when exposed to the cold pressor test. Thirty‐six participants were divided into two groups based on their subjective exercise tolerance profiles. During the test, participants' psychophysiological reactivity was monitored via heart rate variability. Participants were also required to answer questions about their perceptual and affective states at the beginning and immediately after the stress test. The study revealed insights into dominance perception and emotional states among individuals with varying subjective exercise tolerance levels. High‐tolerant individuals endured physical discomfort longer (~50 s) and exhibited higher perceived dominance at the outset of the test when compared to their low‐tolerant counterparts. Despite differences in task performance, both groups experienced more positive affective states post‐task, potentially as a result of a heightened sense of self‐accomplishment. Notably, both groups showed similar levels of psychophysiological reactivity, suggesting a protective effect of physical tolerance on ensuing biological responses. Overall, this study sheds light on the complex relationship between exercise tolerance, dominance perception, and psychophysiological reactivity during physically demanding tasks, enriching our understanding of how developing physical tolerance may impact inhibitory control under stress. [ABSTRACT FROM AUTHOR]

The influence of cardiac phases on cognitive and sensorimotor functions is noteworthy. Specifically, during systole, as opposed to diastole, there is an observed enhancement in tasks demanding the suppression of instructed responses. This suggests that systole contributes to inhibitory control in motor functions. However, the extent to which systolic inhibition is significant in volitional free‐choice actions, such as choosing to execute or refrain from a cue‐initiated response, remains to be clarified. To fill this gap in the current literature, the purpose of this study was to test whether during the systole phase, compared with the diastole phase, the tendency to enact volitional actions decreased due to the systolic inhibitory effect. We used a modified version of the Go/No‐Go task with an added condition for volitional free‐choice actions, where participants could decide whether to respond or not, to test whether systolic inhibition could affect the volitional decision to act. The results showed that participants' responses were less frequent in systole than in diastole in the volitional action condition. Then, to test the robustness of the cardiac effect on volitional actions, we used two established manipulations: the Straw Breathing Manipulation and the Cold Pressor Test, which were able to induce anxiety and increase the heart rate, respectively. Results showed that the systole/diastole difference in the number of volitional action trials in which participants decided to respond tended to remain the same despite all manipulations. Overall, our results provide convergent evidence for the effect of the heart on the decision to act, an effect that appears independent of manipulations of both the physiological and psychological state of the individual. [ABSTRACT FROM AUTHOR]

Concealed information test (CIT) has been utilized for long to perform single measurements. The combination of multiple measures outperforms single measures because of the diverse cognitive processes they reflect and the reduction in random errors facilitated by multiple measures. To further explore the performance of the CIT with multiple measurements, 57 participants were recruited and randomly assigned into guilty and innocent groups. Subsequently, simultaneously recorded reaction time (RT), skin conductance responses (SCRs), heart rate (HR), and neuroimaging data were collected from functional near‐infrared spectroscopy (fNIRS) to detect participants' concealed information in a standard CIT. The results demonstrated that all indicators including RT (area under the curve (AUC) = 0.87), SCRs (AUC = 0.79), HR (AUC = 0.78), and fNIRS (channel 8, AUC = 0.85) could differentiate guilty and innocent groups. Importantly, the use of multiple indicators achieved higher detection efficiency (AUC = 0.96) compared to the use of any single indicator. These results illustrate the effectiveness and feasibility of integrating multiple indicators for concealed information detection in CIT. [ABSTRACT FROM AUTHOR]

Physiological regulation strategies can be effective in reducing anxiety. However, while these strategies are often learned and practised under low‐stress conditions, they are more likely to be required under conditions of high stress. We created virtual reality (VR) biofeedback games to both teach participants a breathing technique and then practise that technique under stress. We present two studies: the first provides a proof of concept, demonstrating that participants can apply the breathing technique during stress, with a significant lowering of both respiration rate and increase in heart rate variability (HRV) under stress (p < .001). The second study explicitly evaluated the effectiveness of training by comparing trained and untrained groups. Training was associated with a significantly greater HRV (p = .008) under stress. In within‐group comparisons of HRV during stress compared to a baseline stressor presented before training, the trained group showed a significantly greater increase compared to untrained controls (p = .025). Our results show the feasibility and potential effectiveness of VR‐based games for biofeedback training under experimentally applied stress. This may offer the opportunity for clinical techniques to more closely reflect the circumstances under which those techniques will be required. [ABSTRACT FROM AUTHOR]

Cooperation, as a mutual collaboration, is a defining feature of human social life. Individual characteristics can influence cooperation. Recent studies have shown a quadratic relationship between cardiac vagal tone (CVT), an index of self‐regulation, and prosocial behaviors. Individual differences in cooperation might also vary as a function of people's environmental sensitivity (ES), i.e., may be influenced by individual differences in the perception and processing of inner and external stimuli. We tested the direct and interactive effect of CVT and ES on cooperative behaviors in two independent samples. We measured heart rate and engagement in cooperative acts in 80 young adults (M = 23.61; SD = 1.60) who were also asked to self‐report on ES. We found an inverted‐U relationship between CVT and cooperative behaviors. ES, on the other hand, did not predict differences in cooperative behaviors but moderated the relationships between CVT and cooperation, although the magnitude of this result was small. Specifically, only among individuals with higher ES cooperative behaviors change as a function of CVT. Highly sensitive individuals with lower or higher CVT, were less cooperative than low sensitive ones. Subsequently, we replicated the same study design in a second sample of 88 undergraduate students (M = 23.69; SD = 4.91). Once again, we found evidence supporting the presence of an inverted‐U relationship between CVT and cooperative behaviors, and we also found that ES moderated the relationships between the quadratic CVT term and cooperation. Our findings add new evidence on physiological self‐regulation as an underlying mechanism of prosocial behaviors, in particular cooperation. In two independent samples, our results showed a quadratic relationship between cardiac vagal tone (CVT) and cooperation. We found that this relationship is moderated by environmental sensitivity (ES). Specifically, only among individuals with higher ES, cooperative behaviors change as a function of CVT. To make the world more cooperative, people should learn how to regulate especially when they are highly sensitive. [ABSTRACT FROM AUTHOR]

Interoception, which refers to the perception of body's internal state, is implicated in emotional processes and psychopathological disorders. Over the last decades, different tools have been developed to measure interoceptive accuracy, or the ability to accurately perceive physiological signals. Most of these tools have focused on cardiac interoception, but respiratory interoception has been less investigated due to the more complex and less portable equipment required. In this study, we suggest a new duration discrimination respiratory (DDR) task that does not require complex equipment. Using an adaptive staircase procedure, this task aims to determine an individual's ability to detect exhalation longer than their resting reference duration. One hundred and twenty‐three healthy subjects completed the DDR task, an interoceptive task of heart rate discrimination, and filled out questionnaires on interoceptive awareness (Multidimensional Assessment of Interoceptive Awareness), alexithymia (Toronto Alexithymia Scale [TAS]), affects (Positive and Negative Affect Scale [PANAS]), and anamnestic. Results demonstrated a good internal consistency (Cronbach's alpha =.93) of the DDR task. On average, subjects needed 99.22% (SD = 36.38) of their reference exhalation time in addition to reference exhalation to detect a prolonged exhalation. Higher self‐reported fitness levels, not counting during the DDR task and lower difficulty in describing feelings (TAS subscale), predicted higher respiratory discrimination duration. In conclusion, this study demonstrates the utility of the DDR task as a valid measure of interoception. Growing interest in interoception highlights the need for reliable measures. Respiratory interoception is understudied compared to cardiac interoception. Non‐portable equipment for respiratory measures is limiting clinical research. Our task provides a portable and ecological measure of respiratory interoception. [ABSTRACT FROM AUTHOR]

Transcranial magnetic stimulation (TMS) is pivotal in the field of major depressive disorder treatment. Due to its unsatisfied response rate, an increasing number of researchers have turned their attention towards optimizing TMS site localization. Since the influence of TMS in reducing heart rate (HR) offers insights into its regulatory impact on the autonomic nervous system, a novel approach, called neurocardiac‐guided TMS (NCG–TMS), has been proposed to pinpoint the brain region eliciting the maximal individual reduction in HR as a personalized optimal stimulation target. The present study intends to systematically explore the effects of stimulation frequency, left and right hemispheres, stimulation positions, and individual differences on HR modulation using the NCG–TMS method. In experiment 1, low‐frequency TMS was administered to 30 subjects, and it was found that low‐frequency NCG–TMS significantly downregulated HR, with more significant effects in the right hemisphere than in the left hemisphere and the prefrontal cortex than in other brain areas. In experiment 2, high‐frequency NCG–TMS stimulation was administered to 30 subjects, showing that high‐frequency NCG–TMS also downregulated HR and had the greatest modulatory effect in the right prefrontal region. Simultaneously, both experiments revealed sizeable individual variability in the optimal stimulation site, which in turn validated the feasibility of the NCG–TMS method. In conclusion, the present experiments independently replicated the effect of NCG–TMS, provided an effect of high‐/low‐frequency TMS stimulation to downregulate HR, and identified a right lateralization of the HR modulation effect. This study independently validated the neuro‐cardiac‐guided transcranial magnetic stimulation (TMS) technique through high‐frequency and low‐frequency TMS. The findings not only unveiled the group‐level heart rate regulatory effects of the right prefrontal cortex but also uncovered individual differences in regulatory responses. These results offer novel theoretical support for the personalized clinical application of TMS in modulating the autonomic nervous system. [ABSTRACT FROM AUTHOR]

Why should researchers measure psychophysiological processes repeatedly over time? The study of psychophysiology inherently involves sampling biological processes as they manifest over time. The most common approach is to use a brief sample to make conclusions about how individuals or groups differ. Although these types of between‐subject comparisons have utility for understanding individual and group differences, many of the important conceptual questions in the field involve processes that are dynamic, varying within individuals over time. Using examples from the literature on affect regulation, this conceptual review contrasts three types of study designs: the classic single‐observation design and the aggregated and temporally linked repeated observation designs, which have great promise for measuring variables that fluctuate dynamically over time. Importantly, these designs can be integrated to elucidate research questions about risk (when and for whom will the likelihood of an unwanted outcome occurring increase?), mechanisms (how and why does a change in psychophysiology contribute to a change in another process of interest?), and interventions (how and when should interventions take place to modify an outcome?). Researchers are encouraged to implement intensive sampling in their research, which can be conducted in traditional laboratory settings (e.g., fMRI, event‐related brain potentials, and heart rate variability) and in ecologically valid contexts in everyday life using ambulatory assessment. Many important conceptual questions in the field of psychophysiology involve dynamic processes that vary within individuals over time. This article highlights research designs for measuring psychophysiological processes that can be integrated to elucidate research questions about risk (when and for whom will the likelihood of an outcome occurring increase?), mechanisms (how and why does a change in psychophysiology contribute to a change in another process of interest?), and interventions (how and when should interventions take place?). [ABSTRACT FROM AUTHOR]

This study investigated the role of arousal and effort costs in the cognitive benefits of alternating between sitting and standing postures using a sit‐stand desk, while measuring executive functions, self‐reports, physiology, and neural activity in a 2‐h laboratory session aimed to induce mental fatigue. Two sessions were conducted with a one‐week gap, during which participants alternated between sitting and standing postures each 20‐min block in one session and remained seated in the other. In each block, inhibition, switching, and updating were assessed. We examined effects of time‐on‐task, acute (local) effects of standing versus sitting posture, and cumulative (global) effects of a standing posture that generalize to the subsequent block in which participants sit. Results (N = 43) confirmed that time‐on‐task increased mental fatigue and decreased arousal. Standing (versus sitting) led to acute increases in arousal levels, including self‐reports, alpha oscillations, and cardiac responses. Standing also decreased physiological and perceived effort costs. Standing enhanced processing speed in the flanker task, attributable to shortened nondecision time and speeded evidence accumulation processes. No significant effects were observed on higher‐level executive functions. Alternating postures also increased heart rate variability cumulatively over time. Exploratory mediation analyses indicated that the positive impact of acute posture on enhanced drift rate was mediated by self‐reported arousal, whereas decreased nondecision time was mediated by reductions in alpha power. In conclusion, alternating between sitting and standing postures can enhance arousal, decrease effort costs, and improve specific cognitive and physiological outcomes. We studied the impact of standing on executive functions and physiology using a unique multi‐method approach that investigated the effect of alternating between sitting and standing on cardiac physiology, neural oscillations, and executive functions. Standing improved neural and physiological arousal, enhanced overall task performance in a flanker task, while also decreasing physiological and perceived effort costs, and increasing heart rate variability over time. These findings emphasize the benefits of alternating between seated and standing postures for the body and the brain. [ABSTRACT FROM AUTHOR]

The ability to flexibly transition between defensive states is crucial for adaptive responding in life‐threatening situations. Potentially threatening situations typically induce a sustained feeling of apprehension in association with hypervigilance, while acute threat is usually characterized by an intense and transient response to cope with the imminent danger. While potential and acute threat states have traditionally been viewed as mutually exclusive, this distinction is being challenged by a growing body of evidence suggesting a more complex interplay during simultaneous activation of these states. However, the interaction between potential and acute threat on a psychophysiological level remains elusive. To fill this gap, 94 healthy individuals participated in one of two contextual fear‐conditioning paradigms. In both paradigms, a differential fear‐learning phase was conducted, followed by a test phase in which the conditioned stimuli were presented in front of either conditioned or inherently aversive contextual images compared to neutral contexts. To capture defensive responses, we recorded subjective (threat and expectancy ratings) and physiological (electrodermal and cardiovascular) activity to the conditioned stimuli as a function of contextual threat. Besides indices of successful fear conditioning, our results revealed stronger threat and unconditioned stimulus expectancy ratings, cardiac deceleration, and skin conductance responses for threat and safety cues presented in inherently aversive compared to neutral contexts. Conditioned contexts had less impact on physiological responses to threat and safety cues than inherently aversive contexts. These findings provide new insights into the additive nature of defensive responses to fear cues and situations of contextual threat. Recent research challenges the idea that defensive states induced by potential and acute threat are mutually exclusive. In this study, we observed enhanced defensive responses to acute threat stimuli during aversive contexts as indexed by heart rate and skin conductance responses, indicating an interplay between potential and acute threat states that is influenced by contextual threat levels. [ABSTRACT FROM AUTHOR]

Chronic loneliness and low perceived social support have been recognized as risk factors for both mental and cardiovascular disorders. It has been proposed that their link to psychophysiological problems may involve changes in parasympathetic activity. However, the exact underlying psychopathological mechanisms and the moderating effects of gender are still not thoroughly examined. Thus, the present study investigated associations between perceived social functioning and resting vagal tone in the context of potential cognitive and subclinical mediators and gender differences. Three hundred twenty‐five young adults (aged 18–35, 180 women) underwent an electrocardiogram measurement of 6‐minute resting heart rate variability (HRV). They also completed questionnaires assessing loneliness, perceived social support, social cognitive biases, depressive and social anxiety symptoms, and general mental health. In men, HRV was significantly and negatively associated with poorer perceived social functioning, depressive symptoms, and self‐reported social cognitive biases, while in women, there was a quadratic link between HRV and depressive symptoms and HRV and general mental health. Moderated mediation analysis revealed that depressive symptoms fully mediated the relationship between perceived social functioning and HRV in men. The results suggest that decreased resting vagal tone in lonely individuals is linked to depressive symptomatology rather than to specific social cognitive biases and that this association is significant only in men. While previous work on the relationship between loneliness and parasympathetic activity has yielded mixed results, the present study provides evidence for an association between reduced resting vagal tone, loneliness, and perceived social support. Importantly, we showed that this association was mostly related to subclinical depressive symptoms and was only observed in men, which may help better understand individual differences related to maladaptive physiological processes in lonely individuals. [ABSTRACT FROM AUTHOR]

Physiologically based stress detection systems have proven to be effective in identifying different stress conditions in the body to determine the source of stress and be able to counteract it. However, some stress conditions have not been widely studied, including thermal stress, cognitive stress, and combined (thermal–cognitive) stress conditions, which are frequently encountered in work or school environments. In order to develop systems to detect and differentiate these conditions, it is necessary to identify the physiological indicators that characterize each of them. The present research aims to identify which physiological indicators (heart rate, respiratory rate, galvanic skin response, and local temperature) could differentiate different stress conditions (no‐stress, cognitive stress, thermal stress, and combined (thermal–cognitive) stress conditions). Thirty participants were exposed to cognitive, thermal, and combined stress sources while recording their physiological signals. The findings indicate that both mean heart rate and mean galvanic skin response identify moderate thermal and cognitive stress conditions as distinct from a no‐stress condition, yet they do not differentiate between the two stress conditions. Additionally, heart rate uniquely identifies the cognitive–thermal stress condition, effectively distinguishing this combined stress condition from the singular stress conditions and the no‐stress condition. Mean local temperature specifically signals thermal stress conditions, whereas mean respiratory rate accurately identifies cognitive stress conditions, with both indicators effectively separating these conditions from each other and from the no‐stress condition. This is the first basis for differentiating thermal and cognitive stress conditions through physiological indicators. Different sources of stress (thermal and cognitive) generate different physiological responses in the body. Mean heart rate, mean local temperature, mean respiratory rate, and mean galvanic skin response allow to differentiate between different stress conditions in the body. Physiological indicators can be used to develop signal‐based detection systems to identify different stress conditions. [ABSTRACT FROM AUTHOR]

Adapting to the ever‐changing demands of the environment requires a complex interplay between cognitive‐affective, neuronal, and autonomic processes. Vagally mediated heart rate variability (vmHRV) is positively associated with both cognitive‐affective functioning and prefrontal cortex (PFC) activity. Accordingly, the Neurovisceral Integration Model has posited a shared role of the PFC in the regulation of cognitive‐affective processes and autonomic nervous system (ANS) activity. While there are numerous correlational findings in this regard, no study so far has investigated whether the manipulation of PFC activity induces changes in vmHRV and cognitive‐affective processing in an inter‐dependent manner. In a sample of 64 participants, we examined the effects of continuous (cTBS; n = 21) and intermittent theta‐burst stimulation (iTBS; n = 20) compared to sham stimulation (n = 23) over the left dorsolateral PFC (dlPFC) on vmHRV and cognitive‐affective processing within an emotional stop‐signal task (ESST). Our results revealed that both resting vmHRV and vmHRV reactivity predicted cognitive‐affective processing. Furthermore, we found a dampening effect of cTBS on resting and on‐task vmHRV, as well as an enhancing effect of iTBS on ESST performance. Our results show no direct association between vmHRV changes and ESST performance alterations following stimulation. We interpret our results in the light of a hierarchical model of neurovisceral integration, suggesting a dynamical situation‐dependent recruitment of higher‐order cortical areas like the dlPFC in the regulation of the ANS. In conclusion, our results highlight the complex interplay between PFC activity, autonomic regulation, and cognitive‐affective processing, emphasizing the need for further research to understand the causal dynamics of the underlying neural mechanisms. Our study represents the first attempt to use repetitive transcranial magnet stimulation (rTMS) to test the relationship between prefrontal activity, vagally mediated heart rate variability (vmHRV) and cognitive‐affective processing, suggested by the Neurovisceral Integration Model. While we did not find hypothesized links between changes in vmHRV and cognitive‐affective processing induced by rTMS over the left dorsolateral prefrontal cortex (dlPFC), our results indicate flexible recruitment of higher‐order cortical areas, such as the left dlPFC in autonomic regulation. [ABSTRACT FROM AUTHOR]

This Committee Report provides methodological, interpretive, and reporting guidance for researchers who use measures of heart rate (HR) and heart rate variability (HRV) in psychophysiological research. We provide brief summaries of best practices in measuring HR and HRV via electrocardiographic and photoplethysmographic signals in laboratory, field (ambulatory), and brain‐imaging contexts to address research questions incorporating measures of HR and HRV. The Report emphasizes evidence for the strengths and weaknesses of different recording and derivation methods for measures of HR and HRV. Along with this guidance, the Report reviews what is known about the origin of the heartbeat and its neural control, including factors that produce and influence HRV metrics. The Report concludes with checklists to guide authors in study design and analysis considerations, as well as guidance on the reporting of key methodological details and characteristics of the samples under study. It is expected that rigorous and transparent recording and reporting of HR and HRV measures will strengthen inferences across the many applications of these metrics in psychophysiology. The prior Committee Reports on HR and HRV are several decades old. Since their appearance, technologies for human cardiac and vascular monitoring in laboratory and daily life (i.e., ambulatory) contexts have greatly expanded. This Committee Report was prepared for the Society for Psychophysiological Research to provide updated methodological and interpretive guidance, as well as to summarize best practices for reporting HR and HRV studies in humans. [ABSTRACT FROM AUTHOR]

The effect of stress on risk‐taking or risk‐averse behavior in decision‐making has been inconclusive in previous research, with few studies revealing the underlying neural mechanisms. This study employed event‐related potentials technique and combined a social cold pressor assessment test with a mental arithmetic task to induce stress responses, aiming to investigate the influence of exogenous stress on the risk decision‐making process. Stress induction results indicated that, in addition to raising heart rate and blood pressure, stress responses were accompanied by enhanced negative emotions, diminished positive emotions, and alterations in neural activity. The outcomes of risk decision‐making showed that stress did not significantly affect risk preference or time of choice but did reduce the feedback‐related negativity/reward positivity, with a particularly significant effect observed for large outcomes. Stress also altered the amplitude of the P3 component, with stress decreasing the P3 value for winning outcomes relative to losing outcomes. The study suggests that understanding how stress affects risk preference should consider the emotional valence induced by stress. Contrary to the reward sensitivity hypothesis, stress weakened reward sensitivity. Stress led to changes in the allocation of cognitive resources for outcome evaluation: compared to negative outcomes, stress reduced cognitive resources for positive outcomes, which might be related to the enhanced negative emotions induced by stress. The study highlights the importance of focusing on the subjective emotional experience induced by stress in future research on stress and risk decision‐making. We find that stress with negative emotions weakens reward sensitivity, which challenges the reward sensitivity hypothesis. Stress also modifies cognitive resource allocation for outcome evaluation: compared to negative outcomes, stress reduced cognitive resources for positive outcomes. This study underscores the significance of incorporating emotional experiences induced by stress into future investigations about stress and risk decision‐making. [ABSTRACT FROM AUTHOR]

Vagally‐mediated heart rate variability (vmHRV) is a physiological index reflecting parasympathetic activity that has been linked to emotion regulation (ER) capacity. However, very limited research has examined associations of physiological indices of regulation such as vmHRV with emotional functioning in daily life. The few studies that exist have small samples sizes and typically focus on only a narrow aspect of ER or emotional functioning. In this study, we examined associations between vmHRV assessed in the laboratory and emotional/mental health functioning in daily life using a 7‐day ecological momentary assessment design in 303 adult community participants. We hypothesized that higher resting vmHRV would be associated with higher positive affect (PA), lower negative affect (NA), less affective variability, greater well‐being, fewer dysphoria symptoms, greater use of engagement ER strategies, and less use of avoidance ER strategies, as assessed in daily life. Results revealed that higher resting vmHRV in the laboratory (as indexed by both high frequency heart rate variability, HF‐HRV, and the root mean of successive square deviations between heart beats, RMSSD) was significantly associated with less frequent use of avoidance ER strategies in daily life. Theoretical and clinical implications are discussed, including the association of vmHRV with negatively valenced, rather than positively valenced, daily life experiences. [ABSTRACT FROM AUTHOR]

Vagally mediated heart rate variability (vmHRV) at resting state has been associated to cognitive functions dependent on cognitive control, such as memory. However, little is known about the phasic interaction between cognitive and autonomic control. In a pre‐registered within‐between‐subject designed experiment, the potential of vmHRV biofeedback to simultaneously stimulate vmHRV during memory processing and cognitive control over long‐term memory was tested, along with investigating psychophysiological association. 71 young healthy adults completed (twice) a false memory task in virtual reality. Immediately before memory encoding and retrieval, participants practiced either vmHRV biofeedback or a control breathing exercise. Cognitive control over long‐term memory was assessed as the confidence toward false memories and the capability to discriminate them from true memories. Resting‐state vmHRV before each test and phasic vmHRV during memory encoding and retrieval were measured as the root mean square differences (RMSSD) in the heart period. vmHRV biofeedback had neither an immediate effect on measures of cognitive control over long‐term memory nor on phasic RMSSD. Moreover, neither resting‐state nor phasic vmHRV correlated to the cognitive scores. Consequently, the utility of HRV biofeedback as a psychophysiological stimulation tool and a link between vmHRV and cognitive control over long‐term memory could not be verified. Exploratory analyses revealed that baseline shift in parasympathetic activity confounded the psychophysiological association. Future directions are provided that could shed light on the relationship between cognition and vmHRV. The results add a nuanced view on the psychophysiological relationship between autonomic and cognitive control that contradicts previous research. We provide evidence that HRV state measures assessed at baseline or during memory processing do not associate with cognitive control over long‐term memory assessed as false memory production. Moreover, short HRV biofeedback proved not to be a viable HRV stimulation method to study the heart–brain interaction. We uncovered influencing factors on the psychophysiological relationship and propose a new analysis approach important for future studies. [ABSTRACT FROM AUTHOR]

Variations in cardioafferent traffic are relayed to the brain via arterial baroreceptors and have been shown to modulate perceptual processing. However, less is known about the cognitive‐behavioral consequences of these effects and their role during stress. Here, we investigated in how far automatic responses during the Simon task were modulated by exposure to a laboratory stressor and the different phases of the cardiac cycle. In this study, 30 participants performed three blocks of a combined horizontal and vertical Simon task, which is characterized by either sensorimotor or cognitive response conflicts, respectively. Before each block, subjects were exposed to both the cold pressor test (CPT) and a control condition according to a within‐subjects design. Target stimuli were presented during either systole or diastole. Behavioral and EEG‐correlates of task processing were assessed along with subjective, cardiovascular, and endocrine measures of stress. The stress induction was successful yielding significant increases in all these measures compared to control. Moreover, we found the expected Simon effects: in incompatible compared to compatible trials performance was decreased and LRP latency as well as anterior N2 area increased. Importantly, accuracy was improved in compatible but reduced in incompatible trials during systole vs. diastole but only in the horizontal Simon condition. Stress dampened N2 area, however, no interactions with cardiac cycle were evident. These results indicate a faciliatory effect of cardioafferent traffic on automated sensorimotor processes. Our study confirms a specific cardiac‐cycle‐time effect suggesting enhanced automatic response activation during phases of increased cardioafferent activity. Replicating previous findings, this effect seems to bear upon hardwired rather than cognitively mediated connections. While no interactions were found, this study is also the first to investigate such effects after stress induction. [ABSTRACT FROM AUTHOR]

Heart rate variability (HRV) is an early marker of risk for various health conditions, and its analysis serves as a valuable tool for assessing older adults. This study aimed to describe the reference values of HRV parameters in older adults through a systematic review of the literature. The review included searches in MEDLINE (via PubMed®), EMBASE, Latin American and Caribbean Health Literature, Scopus, and Web of Science (WOS). Studies presenting reference values for at least one HRV linear analysis measure in older adults were considered eligible. Out of 1618 studies identified, only 11 met the inclusion criteria. Sample sizes of older adults ranged from 21 to 6250 subjects. The HRV measures assessed (mean RR intervals, SDNN, RMSSD, PNN50, LF, HF, and LF/HF ratio) varied significantly between studies, with no standardized methods for HRV analysis. We concluded that reference values for HRV measures in older adults vary widely between studies. The scientific literature on HRV reference values in older adults is still limited, and future studies should standardize assessment methods for HRV measures in this population. [ABSTRACT FROM AUTHOR]

Freezing is one of the most extensively studied defensive behaviors in rodents. Both reduced body and gaze movements during anticipation of threat also occur in humans and have been discussed as translational indicators of freezing but their relationship remains unclear. We thus set out to elucidate body and eye movements and concomitant autonomic dynamics in anticipation of avoidable threat. Specifically, 50 participants viewed naturalistic pictures that were preceded by a colored fixation cross, signaling them whether to expect an inevitable (shock), no (safety), or a potential shock (flight) that could be avoided by a quick button press. Body sway, eye movements, the heart rate and skin conductance were recorded. We replicated previously described reductions in body sway, gaze dispersion, and the heart rate, and a skin conductance increase in flight trials. Stronger reductions in gaze but not in body sway predicted faster motor reactions on a trial‐wise basis, highlighting their functional role in action preparation. We failed to find a trait‐like relationship between body and gaze movements across participants, but their temporal profiles were positively related within individuals, suggesting that both metrics partly reflect the same construct. However, future research is desirable to assess these response patterns in naturalistic environments. A more ethological examination of different movement dynamics upon threat would not only warrant better comparability between rodent and human research but also help determine whether and how eye‐tracking could be implemented as a proxy for fear‐related movements in restricted brain imaging environments. Our article unravels the relationship between body and eye movements in human threat anticipation, drawing parallels with freezing behavior in rodents. We reveal a physio‐behavioral defensive state, emphasize eye‐tracking's potential in neuroimaging, and spotlight the need for improved translational research practices across species. [ABSTRACT FROM AUTHOR]

Transcranial direct current stimulation (tDCS) of the prefrontal cortex (PFC) modulates the autonomic nervous system by activating deeper brain areas via top‐down pathway. However, effects on the nervous system are heterogeneous and may depend on the amount of current that penetrates. Therefore, we aimed to investigate the variable effects of tDCS on heart rate variability (HRV), a measure of the functional state of the autonomic nervous system. Using three prefrontal tDCS protocols (1.5, 3 mA and sham), we associated the simulated individual electric field (E‐field) magnitude in brain regions of interest with the HRV effects. This was a randomized, double‐blinded, sham‐controlled and within‐subject trial, in which healthy young‐adult participants received tDCS sessions separated by 2 weeks. The brain regions of interest were the dorsolateral PFC (DLPFC), anterior cingulate cortex, insula and amygdala. Overall, 37 participants were investigated, corresponding to a total of 111 tDCS sessions. The findings suggested that HRV, measured by root mean squared of successive differences (RMSSD) and high‐frequency HRV (HF‐HRV), were significantly increased by the 3.0 mA tDCS when compared to sham and 1.5 mA. No difference was found between sham and 1.5 mA. E‐field analysis showed that all brain regions of interest were associated with the HRV outcomes. However, this significance was associated with the protocol intensity, rather than inter‐individual brain structural variability. To conclude, our results suggest a dose‐dependent effect of tDCS for HRV. Therefore, further research is warranted to investigate the optimal current dose to modulate HRV. By dissecting the effects of different tDCS protocols on HRV and linking them to individual brain anatomy, we have uncovered a dose‐dependent relationship between tDCS dose and HRV modulation. These findings underscore the importance of optimizing tDCS for HRV modulation, advancing our understanding of neurostimulation's potential in autonomic nervous system regulation. [ABSTRACT FROM AUTHOR]

Dysregulation of the autonomic nervous system (ANS) is commonly observed in various mental disorders, particularly when individuals engage in prolonged cognitive‐emotional tasks that require ANS adjustment to workload. Although the understanding of the temporal dynamics of sympathetic and parasympathetic tones in obsessive‐compulsive disorder (OCD) is limited, analyzing ANS reactions to cognitive‐emotional workload could provide valuable insights into one of the underlying causes of OCD. This study investigated the temporal dynamics of heart rate (HR) and pupil area (PA) while participants with OCD and healthy volunteers solved antisaccade tasks, with affective pictures serving as central fixation stimuli. The data of 31 individuals with OCD and 30 healthy volunteers were included in the study, comprising three separate blocks, each lasting approximately 8 min. The results revealed an increase in sympathetic tone in the OCD group, with the most noticeable rise occurring during the middle part of each block, particularly during the presentation of negative stimuli. Healthy volunteers demonstrated adaptive temporal dynamics of HR and PA from the first block to the last block of tasks, whereas individuals with OCD exhibited fewer changes over time, suggesting a reduced adaptation of the ANS sympathetic tone to cognitive‐emotional workload in OCD. Altered autonomic nervous system responses in patients with OCD could potentially underlie the causes of obsessive‐compulsive disorder; however, they have not been sufficiently investigated at present. By examining the temporal dynamics of pupil area and heart rate, we gain deeper insights into how individuals with obsessive‐compulsive disorder react to cognitive‐emotional stimuli. [ABSTRACT FROM AUTHOR]

Heart rate variability biofeedback (HRVB) is an efficacious treatment for depression and anxiety. However, translation to digital mental health interventions (DMHI) requires computing and providing real‐time HRVB metrics in a personalized and user‐friendly fashion. To address these gaps, this study validates a real‐time HRVB feedback algorithm and characterizes the association of the main algorithmic summary metric—HRVB amplitude—with demographic, psychological, and health factors. We analyzed HRVB data from 5158 participants in a therapist‐supported DMHI incorporating slow‐paced breathing to treat depression or anxiety symptoms. A real‐time feedback metric of HRVB amplitude and a gold‐standard research metric of low‐frequency (LF) power were computed for each session and then averaged within‐participants over 2 weeks. We provide HRVB amplitude values, stratified by age and gender, and we characterize the multivariate associations of HRVB amplitude with demographic, psychological, and health factors. Real‐time HRVB amplitude correlated strongly (r =.93, p <.001) with the LF power around the respiratory frequency (~0.1 Hz). Age was associated with a significant decline in HRVB (β = −0.46, p <.001), which was steeper among men than women, adjusting for demographic, psychological, and health factors. Resting high‐ and low‐frequency power, body mass index, hypertension, Asian race, depression symptoms, and trauma history were significantly associated with HRVB amplitude in multivariate analyses (p's <.01). Real‐time HRVB amplitude correlates highly with a research gold‐standard spectral metric, enabling automated biofeedback delivery as a potential treatment component of DMHIs. Moreover, we identify demographic, psychological, and health factors relevant to building an equitable, accurate, and personalized biofeedback user experience. Heart rate variability biofeedback (HRVB) is an efficacious treatment for depression and anxiety, although translation to digital mental health interventions (DMHI) is hindered by the lack of normative data for real‐time HRVB metrics. This research demonstrates the utility of HRVB algorithms tailored to age and gender for DMHIs. The translation of precision care HRVB algorithms into DMHIs and other real‐world settings will improve engagement and real‐world effectiveness of biofeedback interventions for common mental health symptoms. [ABSTRACT FROM AUTHOR]

Imagery has been associated with cardiovascular and psychological responses to stress; however, the mechanisms underlying this association are not fully understood. The present study examined if the ability to image mastering challenging or difficult situations moderated the relationship between heart rate reactivity and perceptions of stress and physiological arousal experienced during acute stress. Four hundred and fifty‐eight participants completed a standardized laboratory stress protocol with heart rate being measured throughout. After completing an acute psychological stress task, participants rated how stressed and physiologically aroused they felt (i.e., intensity) and whether they perceived the stress and physiological arousal as being helpful/unhelpful to performance (i.e., interpretation). Mastery imagery ability was assessed by questionnaire. Moderation analyses controlling for gender demonstrated that imagery ability moderated the relationship between heart rate reactivity and interpretation of stress (β = 0.015, p =.003) and perceived physiological arousal (β = 0.013, p =.004). Simple slope analysis indicated that in those with higher imagery ability, heart rate reactivity was associated with stress and arousal being perceived as more positive toward performance. Imagery ability did not moderate the relationship between heart rate reactivity and perceived stress intensity or physiological arousal intensity (p's >.05), but imagery ability did predict lower perceived stress intensity (β = −0.217, p <.001) and perceived physiological arousal intensity (β = −0.172, p <.001). Higher mastery imagery ability may possibly help individuals perceive responses to stress as more beneficial for performance and thus be an effective coping technique. While previous research has shown imagery being associated with cardiovascular and psychological responses to stress, the mechanisms underlying this association are not fully understood. By evidencing that imagery ability moderates the relationship between heart rate reactivity and interpretation of stress and perceived physiological arousal, we demonstrate a mechanism through which higher mastery imagery ability could help individuals perceive responses to stress as more beneficial for performance. [ABSTRACT FROM AUTHOR]

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

Recent evidence suggests that the autonomic nervous system can contribute to memory consolidation during sleep. Whether fluctuations in cardiac autonomic activity during sleep following physical exercise contribute to the process of memory consolidation has not been studied. We assessed the effects of a non‐rapid eye movement (NREM) nap following acute exercise on cardiac autonomic regulation assessed with heart rate variability (HRV) to examine if HRV influences memory processes. Fifty‐six (59% female) healthy young adults (23.14 ± 3.74 years) were randomly allocated to either the exercise plus nap (ExNap, n = 27) or nap alone (NoExNap, n = 29) groups. The ExNap group performed a 40‐minute moderate‐intensity cycling, while the NoExNap group was sedentary prior to learning 45 neutral pictures for a later test. Subsequently, participants underwent a 60‐minute NREM nap while measuring EKG, followed by a visual recognition test. Our results indicated that heart rate did not significantly differ between the groups (p =.243), whereas vagally mediated HRV indices were lower in the ExNap group compared to the NoExNap group (p <.05). There were no significant differences in sleep variables between the groups (p >.05). Recognition accuracy was significantly higher in the ExNap group than in the NoExNap group (p =.027). In addition, the recognition accuracy of the ExNap group was negatively associated with vagally mediated HRV (p <.05). Pre‐nap acute exercise appears to attenuate parasympathetic activity and to alter the relationship between memory and cardiac autonomic activity. Our findings reinforce those of previous studies and together show the contribution of parasympathetic tone to memory consolidation during sleep. The negative relationship between recognition memory performance and parasympathetic activity indicates that the alteration of parasympathetic tone following acute exercise may be unfavorable to memory consolidation. [ABSTRACT FROM AUTHOR]

The tendency to ruminate (i.e., repetitive, self‐referential, negative thoughts) is a maladaptive form of emotional regulation and represents a transdiagnostic vulnerability factor for stress‐related psychopathology. Vagally‐mediated heart rate variability (vmHRV) provides a non‐invasive, surrogate measure of vagal modulation of the heart, and higher HRV is considered an indicator of susceptibility, or ability to respond to stress. Past research has suggested a link between trait rumination and vmHRV; however, inconsistent results exist in healthy individuals. In this study, we investigated the association between the tendency to ruminate, brooding, and reflection (using the Ruminative Response Scale) with vmHRV measured at baseline in a healthy population using a large cross‐sectional dataset (N = 1189, 88% female; mean age = 21.55, ranging from 17 to 48 years old), which was obtained by combining samples of healthy individuals from different studies from our laboratory. The results showed no cross‐sectional correlation between vmHRV and trait rumination (confirmed by Bayesian analysis), even after controlling for important confounders such as gender, age, and depressive symptoms. Also, a non‐linear relationship was rejected. In summary, based on our results in a large sample of healthy individuals, vmHRV is not a marker of trait rumination (as measured by the Ruminative Response Scale). HRV, measured at rest, has been considered an index of emotional flexibility. As such, the tendency to ruminate following a negative experience has been linked to lower vmHRV, even though experimental findings remain inconsistent. Based on a large‐scale database, we show no correlation between vmHRV and the tendency to ruminate in healthy adults. These findings imply that the relationship between vmHRV and vulnerability to psychopathology in healthy individuals should be re‐evaluated. [ABSTRACT FROM AUTHOR]

There is evidence that cardiovascular function can influence sensory processing and cognition, which are known to change with age. However, whether the precision of unisensory and multisensory temporal perception is influenced by cardiovascular activity in older adults is uncertain. We examined whether seated resting heart rate (RHR) was associated with unimodal visual and auditory temporal discrimination as well as susceptibility to the audio‐visual Sound Induced Flash Illusion (SIFI) in a large sample of older adults (N = 3232; mean age = 64.17 years, SD = 7.74, range = 50–93; 56% female) drawn from The Irish Longitudinal Study on Ageing (TILDA). Faster seated RHR was associated with better discretization of two flashes (but not two beeps) and increased SIFI susceptibility when the audio‐visual stimuli were presented close together in time but not at longer audio‐visual temporal offsets. Our findings suggest a significant relationship between cardiovascular activity and the precision of visual and audio‐visual temporal perception in older adults, thereby providing novel evidence for a link between cardiovascular function and perceptual function in aging. We present novel evidence for a relationship between resting heart rate and visual and audio‐visual temporal precision in older adults. This indicates that the cardiovascular and perceptual systems, both of which change with age and are associated with broader physical and cognitive health, are interlinked in aging. [ABSTRACT FROM AUTHOR]

Respiratory sinus arrhythmia (RSA) is an index of parasympathetic nervous system activity reflecting respiratory influences on heart rate. This influence is typically measured as high frequency heart rate variability (HF‐HRV) or root mean square of successive differences (RMSSD) of adjacent inter‐beat intervals. Examining the long‐term stability of its measurement is important as levels of resting RSA have been conceptualized as a marker of individual differences; in particular, of an individual's autonomic regulation and affect‐related processes, including emotion regulation. At present, it is not known if resting RSA levels reflect stable differences over a long‐term period (i.e., >1 year). Even less is known about how RSA stability differs as a function of depression history and whether it relates to depression risk trajectories. In the present study, we examined the 1.5‐year test–retest reliability of resting RSA using the intraclass correlation coefficient (ICC) in 82 adults: n = 41 with a history of depression (ever‐depressed); n = 41 controls with no depression history (never‐depressed). HF‐HRV was fairly stable in both groups (ever‐depressed ICC = 0.55, never‐depressed ICC = 0.54). RMSSD was also fairly stable in ever‐depressed adults (ICC = 0.57) and never‐depressed controls (ICC = 0.40). ICC values for both indices did not differ between groups per overlapping 95% confidence intervals. Therefore, RSA stability as assessed by both frequency (HF‐HRV) and time domain (RMSSD) measures was not attenuated by a depression history. Implications and the need for future research are discussed. Researchers commonly utilize resting levels of parasympathetically‐mediated heart rate variability (e.g., HF‐HRV, RMSSD) to assess emotion regulation in healthy and clinical samples, particularly depression. However, little is known about its long‐term stability, and even less so in the presence of psychopathology. Our findings indicate that resting HF‐HRV and RMMSD are fairly stable indices of RSA over a period of 1.5 years, on average, among adults with and without a history of depression. [ABSTRACT FROM AUTHOR]

We describe methods and software resources for a bioimpedance measurement technique, 'trans‐radial electrical bioimpedance velocimetry' (TREV) that allows for the non‐invasive monitoring of relative cardiac contractility and stroke volume. After reviewing the relationship between the measurement and cardiac contractility, we describe the general recording methodology, which requires impedance measurements of the forearm. We provide open‐source Jupyter‐based software (operable on most computers) for deriving cardiac contractility from the impedance measurements. The software includes tools for removing variance associated with heart rate and respiration. We demonstrate the ability of this bioimpedance measurement for tracking beat‐to‐beat changes of contractility in a maximal grip force production task. Critically, the results demonstrate both a reactive increase in contractility with force production, and suggest there is a learned increase in contractility prior to grip onset, consistent with anticipatory allostatic autonomic regulation mediated by sympathetic inotropy. The method and software should be of broad utility for investigations of event‐related cardiac dynamics in psychophysical studies. Our novel bioimpedance measurement technique, trans‐radial bioimpedance velocimetry (TREV) and open‐source analysis software provides a simplified approach to reliably capture perturbations of cardiac contractility. TREV electrode recordings of impedance along the forearm can be used to quantify peak flow acceleration after aortic valve opening, an indicator of contractility. When heart rate and respiration influences are accounted for, the relative changes in contractility are indicative of sympathetic inotropy. The method is demonstrated in an isometric force task, where there is evidence of sympathetic associated effort mobilization prior to grip onset. We provide software operable on most computers to analyse TREV time series. [ABSTRACT FROM AUTHOR]

Although central to theories of emotion, emotional response coherence, that is, coordination among various emotion response systems, has received inconsistent empirical support. This study tests a basic assumption of response coherence, that is, that it characterizes emotional states defining their beginning and end. To do so, we (a) compare response coherence between emotional versus non‐emotional states and (b) examine how emotional coherence changes over time, before, during, and after an emotional episode. Seventy‐nine participants viewed neutral, pleasant, and unpleasant film clips and rated continuously how pleasant they felt (experience) before (anticipation), during, and after (recovery) each clip. Autonomic physiological arousal responses (skin conductance level, heart rate; physiology) and facial expressions (corrugator, zygomatic activity; expression) were recorded. Within‐person cross‐correlations between all emotional response pairs were calculated for each phase. Analyses comparing coherence during emotional versus neutral film viewing showed that only experience‐expression coherence was higher for emotional versus neutral films, indicating specificity for emotional states. Examining coherence across phases indicated that coherence increased from anticipation to emotional film viewing, as expected, for experience‐expression and experience‐physiology pairs (SCL only). Of those pairs, increased coherence returned to baseline during recovery, as theoretically assumed, only for experience‐corrugator activity coherence. Current findings provide empirical support for theoretical views of response coherence as a defining feature of emotional episodes, but mostly for the coherence between experience and facial expressions. Further research needs to investigate the role of sympathetic arousal indices, as well as the role of response coherence in emotional recovery. Emotion theories consider coherence or covariation among emotional responses as a defining feature of emotional states. We examined this assumption empirically by assessing emotional response coherence over time in emotional versus non‐emotional states. Results supported theoretical assertions for increased coherence during emotional states, but only for experience‐expression response systems. Results are also the first to show persistent response coherence during emotional recovery. [ABSTRACT FROM AUTHOR]

Pulse rate variability (PRV) is often used as an alternative to heart rate variability (HRV) to measure psychophysiological function. However, its validity to do so is unclear, especially in adults with spinal cord injury (SCI). This study compared PRV and HRV in adults with higher‐level SCI (SCI‐H, n = 23), lower‐level SCI (SCI‐L, n = 22), and able‐bodied participants (AB n = 44), in a seated position as a function of performance in a reactivity task (Oxford Sleep Resistance Test: OSLER). PRV and HRV was measured using reflective finger‐based photoplethysmography (PPG) and electrocardiography, respectively, at baseline, immediately post‐OSLER, and after five‐minute recovery. Agreement between PRV and HRV was determined by Bland–Altman analysis and differences between PRV and HRV over time by linear mixed effects model (LMM) analysis. Concurrent validity was assessed through correlation analyses between PRV and HRV. Additional correlation analyses were performed with psychosocial factors. Results indicated insufficient to moderate agreement between PRV and HRV. LMM analyses indicated no differences over time for standard deviation of normal‐to‐normal intervals and low‐frequency power but significant differences for root mean square of successive differences and high frequency power. Nevertheless, PRV and HRV were highly correlated (Median r =.878 (.675–.990)) during all assessment periods suggesting sufficient concurrent validity. Similar correlation patterns were also found for PRV and HRV with psychosocial outcomes. While differences existed, results suggest PRV derived from reflective finger‐based PPG is a valid proxy of HRV in tracking psychophysiological function in adults with SCI and could therefore be used as a more accessible monitoring tool. Autonomic dysfunction is a serious problem following a spinal cord injury (SCI), but assessment remains a challenge. We present evidence showing pulse rate variability is a valid measure of autonomic activity in SCI and which arguably, is more accessible in clinical settings than the gold standard heart rate variability. [ABSTRACT FROM AUTHOR]

When EEG recordings are used to reveal interactions between central‐nervous and cardiovascular processes, the cardiac field artifact (CFA) poses a major challenge. Because the electric field generated by cardiac activity is also captured by scalp electrodes, the CFA arises as a heavy contaminant whenever EEG data are analyzed time‐locked to cardio‐electric events. A typical example is measuring stimulus‐evoked potentials elicited at different phases of the cardiac cycle. Here, we present a nonlinear regression method deploying neural networks that allows to remove the CFA from the EEG signal in such scenarios. We train neural network models to predict R‐peak centered EEG episodes based on the ECG and additional CFA‐related information. In a second step, these trained models are used to predict and consequently remove the CFA in EEG episodes containing visual stimulation occurring time‐locked to the ECG. We show that removing these predictions from the signal effectively removes the CFA without affecting the intertrial phase coherence of stimulus‐evoked activity. In addition, we provide the results of an extensive grid search suggesting a set of appropriate model hyperparameters. The proposed method offers a replicable way of removing the CFA on the single‐trial level, without affecting stimulus‐related variance occurring time‐locked to cardiac events. Disentangling the cardiac field artifact (CFA) from the EEG signal is a major challenge when investigating the neurocognitive impact of cardioafferent traffic by means of the EEG. When stimuli are presented time‐locked to the cardiac cycle, both sources of variance are systematically confounded. Here, we propose a regression‐based approach deploying neural network models to remove the CFA from the EEG. This approach effectively removes the CFA on a single‐trial level and is purely data‐driven, providing replicable results. Disentangling the cardiac field artifact (CFA) from the EEG signal is a major challenge when investigating the neurocognitive impact of cardioafferent traffic by means of the EEG. When stimuli are presented time‐locked to the cardiac cycle, both sources of variance are systematically confounded. Here, we propose a regression‐based approach deploying neural network models to remove the CFA from the EEG. This approach removes the CFA effectively on a single‐trial level and is purely data‐driven, providing replicable results. [ABSTRACT FROM AUTHOR]

Individuals with grandiose narcissism exhibit enhanced antagonism and a defensive pattern of discordance between their emotional and physiological reactions to self‐threatening evaluations. Although theoretical perspectives link narcissistic defensiveness to negative emotions, empirical evidence linking grandiose narcissism to emotional reactivity remains mixed. The current study used self‐reported affect, electrocardiography, and facial electromyography (fEMG) to examine whether people scoring high in grandiose narcissism show amplified physiological and self‐reported emotional reactivity to negative social evaluation. Following two challenging cognitive tasks, participants received negative and neutral feedback in a face‐to‐face evaluation situation. Receiving negative feedback decreased self‐reported positive affect and dominance, slowed heart rate, and amplified fEMG activity related to frowning and eye constriction. Although self‐reported emotional reactions were unrelated to grandiose narcissism, fEMG activity associated with negative affect was significantly enhanced by grandiose narcissism. In conclusion, individuals with higher levels of grandiose narcissism may not be willing to report overt emotional reactivity to self‐threatening feedback, but physiological responses "beneath their thin skin" reveal amplified threat‐related facial muscle activity suggestive of a negative emotional state. Although grandiose narcissism is often linked with strong negative emotional reactions to social evaluations, direct evidence of the reactions remains mixed. We show that while narcissistic recipients do not report stronger negative emotions when receiving feedback on their performance than others do, their facial muscle responses to negative feedback are amplified. The findings align with theoretical accounts on narcissistic defensiveness and demonstrate a discordance in narcissistic individuals' self‐reported and physiological reactions to social evaluation. [ABSTRACT FROM AUTHOR]

Autonomic nervous system (ANS) responses such as heart rate (HR) and galvanic skin responses (GSR) have been linked with cerebral activity in the context of emotion. Although much work has focused on the summative effect of emotions on ANS responses, their interaction in a continuously changing context is less clear. Here, we used a multimodal data set of human affective states, which includes electroencephalogram (EEG) and peripheral physiological signals of participants' moment‐by‐moment reactions to emotional provoking video clips and modeled HR and GSR changes using machine learning techniques, specifically, long short‐term memory (LSTM), decision tree (DT), and linear regression (LR). We found that LSTM achieved a significantly lower error rate compared with DT and LR due to its inherent ability to handle sequential data. Importantly, the prediction error was significantly reduced for DT and LR when used together with particle swarm optimization to select relevant/important features for these algorithms. Unlike summative analysis, and contrary to expectations, we found a significantly lower error rate when the prediction was made across different participants than within a participant. Moreover, the predictive selected features suggest that the patterns predictive of HR and GSR were substantially different across electrode sites and frequency bands. Overall, these results indicate that specific patterns of cerebral activity track autonomic body responses. Although individual cerebral differences are important, they might not be the only factors influencing the moment‐by‐moment changes in ANS responses. We show that predicting continuous autonomic responses such as heart rate and galvanic skin responses require an approach that is capable of learning dependence or sequential feature selection in order to improve the performance of prediction. In addition, despite some similarities, the neurophysiological patterns and the peripheral measures that play a role in predicting these two types of autonomic responses are largely distinct. This contributes to the understanding of different autonomic measures being driven by specific and nonspecific neurophysiological associations. [ABSTRACT FROM AUTHOR]

Individuals have unique typing rhythms characterized by specific keystroke dynamics. Changes in state and cardiovascular responding are well documented manifestations of the fight‐flight response to stress. However, as stress also leads to changes in muscle tone and motor control, typing rhythms may also be impacted. We aim to determine which individuals are experiencing stress through their typing rhythms and identify universal keystroke markers of stress. Participants (N = 116) typed 80 repetitions of a 6‐word, 30‐character phrase before and after 15 min of critically evaluated multitasking stress. Cardiovascular, hemodynamic, and state variables were compared across baseline, stress, and recovery periods and measures of typing rhythm were derived for each period and classified using machine‐learning algorithms. Critically evaluated multitasking led to significant changes in all stress measures, demonstrating highly robust stress reactivity. Machine learning algorithms accurately classified stressed typing for each individual based on their typing rhythms; however, no universal keystroke markers of stress were identified. Using typing rhythms. We were able to determine whether an individual was stressed or not, but the markers used for classification differed between individuals. These individual changes may provide opportunities for identifying stressful periods through keystroke monitoring, as well as the potential for early identification of disorders which may impact fine motor control. Typing rhythms could therefore be used to monitor health and well‐being in individuals who use keyboards in various situations. This is the first rigorous assessment of stress and typing rhythms and has led to the development of a feasible and highly reproducible research protocol. Individuals can be identified through their unique typing rhythms. These typing rhythms also change during stressful experiences such that typing produced during stress can be accurately distinguished from typing during neutral periods. Typing rhythms could therefore be used to monitor individuals long‐terms stress‐induced performance and wellbeing. [ABSTRACT FROM AUTHOR]

Selectively attending to threat‐related stimuli in the environment, known as threat bias (TB), is a prominent feature of anxiety. Individuals with high anxiety also tend to show lower heart rate variability (HRV), a reflection of reduced parasympathetic cardiac control. Previous investigations have established associations between low HRV and various attentional processes that facilitate attention to threat, though these have primarily been conducted among non‐anxious individuals. The current analysis, derived from a larger TB modification study, examined the relationship between TB and HRV among a young, nonclinical sample of individuals with either high or low trait anxiety (HTA, LTA, respectively; Mage = 25.8, SD = 13.2, 61.3% female). Consistent with expectations, HTA (β = −.18, p =.087) trended toward an association with higher threat vigilance. A significant moderation effect showed the relationship between HRV and threat vigilance was influenced by TA (β =.42, p =.004). Simple slopes analysis revealed that for the LTA group, lower HRV trended toward higher threat vigilance (p =.123), consistent with expectations. However, this relationship was unexpectedly reversed for the HTA group, for whom higher HRV was a significant predictor of higher threat vigilance (p =.015). These results are interpreted within a cognitive control framework, in which regulatory ability, as assessed via HRV, may influence which cognitive strategy is employed when encountering threatening stimuli. Results suggest that HTA individuals with greater regulatory ability may employ a contrast avoidance mechanism, while those with reduced regulatory ability engage in cognitive avoidance. This is one of the few studies investigating the relationship between vigilance toward threat‐related content (engagement threat bias), trait anxiety, and heart rate variability (HRV). Our findings support an expected association of lower HRV with greater threat vigilance among low trait anxious individuals; however, this relationship is unexpectedly reversed among high trait anxious individuals, with higher HRV predicting greater threat vigilance. [ABSTRACT FROM AUTHOR]

The role of the heart in the experience of time has been long theorized but empirical evidence is scarce. Here, we examined the interaction between fine‐grained cardiac dynamics and the momentary experience of subsecond intervals. Participants performed a temporal bisection task for brief tones (80–188 ms) synchronized with the heart. We developed a cardiac Drift‐Diffusion Model (cDDM) that embedded contemporaneous heart rate dynamics into the temporal decision model. Results revealed the existence of temporal wrinkles—dilation or contraction of short intervals—in synchrony with cardiac dynamics. A lower prestimulus heart rate was associated with an initial bias in encoding the millisecond‐level stimulus duration as longer, consistent with facilitation of sensory intake. Concurrently, a higher prestimulus heart rate aided more consistent and faster temporal judgments through more efficient evidence accumulation. Additionally, a higher speed of poststimulus cardiac deceleration, a bodily marker of attention, was associated with a greater accumulation of sensory temporal evidence in the cDDM. These findings suggest a unique role of cardiac dynamics in the momentary experience of time. Our cDDM framework opens a new methodological avenue for investigating the role of the heart in time perception and perceptual judgment. With the novel consideration of cardiac dynamics in the Drift‐Diffusion Model of temporal decision making, we found a close relationship between heart rate and the perception of millisecond durations. Heart rate before a brief stimulus and the subsequent cardiac orienting response explained components of the perceptual evidence accumulation process to determine the stimulus duration. These findings suggest a unique role for bioenergetics in subsecond time perception. [ABSTRACT FROM AUTHOR]

Physical stress has been found to enhance arousability by visual sexual stimuli on a short‐term basis, as reflected in higher phasic pupil dilation responses, probably mediated by sympathetic nervous system (SNS)‐related processes. However, previous research has not addressed the specificity of this effect in terms of emotional valence, that is, whether it reflects an instance of general excitation transfer or a more specific mechanism. Thus, to further investigate changes in sexual processing after acute stress exposure, 40 male participants underwent either a predominantly sympathetic stressor (3 min sustained handgrip) or similar control procedure. After stress induction, pictures varying in valence as well as sexual versus non‐sexual arousal were presented (for 5000 ms each). Using principal component analysis, pupillary responses during picture viewing were dissociated into fast and slow components (early vs. late response phases). In addition, startle eyeblink responses were elicited by bursts of white noise (50 ms, 105 dB) in half of the trials and recorded at the orbicularis oculi via electromyography. Skin conductance and heart rate were co‐registered, as well. While affective startle modulation and skin conductance responses to emotional stimuli were unaffected by previous stress exposure, both evoked heart‐rate deceleration (but not acceleration) and pupil responses were specifically enhanced with sexually arousing stimuli in stressed participants, and this effect was mediated by blood pressure reactivity as an index of preceding SNS activation. Taken together, our findings provide strong evidence for enhancement of sexual processing by acute stress exposure in men and suggest differential involvement of parasympathetic versus sympathetic mechanisms. Abstract While long‐term stress exposure has been linked to impaired sexual function, animal models of effects of acute stress on sexual arousability have yielded heterogeneous results, and human research is scarce. The present study replicates and extends evidence for increased physiological responsivity to erotic cues after sympathetic nervous system activation (in men), revealing differential involvement of parasympathetic versus sympathetic mechanisms. [ABSTRACT FROM AUTHOR]

Several studies have described, often separately, the relaxing effects of music or odor on the autonomic nervous system (ANS) activity. Only a few studies compared the presentation of these stimuli and their interaction within a same experimental protocol. Here, we examined whether relaxing music (slow‐paced classical pieces) and odor (lavender essential oil) either presented in isolation or in combination would facilitate physiological recovery after cognitive stress. We continuously recorded the electrocardiogram to assess the high‐frequency component of heart rate variability (HF‐HRV), an index of parasympathetic activity, and electrodermal activity (EDA), an index of sympathetic activity, 10 min before, during and 30 min after a cognitive stress (i.e., completing timely constrained cognitively demanding tasks) in 99 participants allocated to four recovery conditions (control N = 26, music N = 23, odor N = 24, music+odor N = 26). The stressing event triggered both a significant increase in EDA and decrease in HF‐HRV (compared to baseline). During the recovery period, the odor elicited a greater decrease in EDA compared to an odorless silent control, whereas no difference in HRV was observed. Conversely, during this period, music elicited a greater increase in HF‐HRV compared to control whereas no difference in EDA was observed. Strikingly, in the multimodal music+odor condition, no beneficial effect was observed on ANS indexes 30 min after stress. Overall, our study confirms that both olfactory and musical stimuli have relaxing effects after stress on ANS when presented separately only, which might rely on distinct neural mechanisms and autonomic pathways. The present study provides evidence that both musical and olfactory stimuli can help the autonomic nervous system regain homeostasis after cognitive stress. Unexpectedly, our research also shows the absence of multisensory benefit ("multimodal paradox"). These findings will contribute to our understanding of the underlying physiological mechanisms involved in the relaxing effects of musical and olfactory stimuli, presented separately or in combination. [ABSTRACT FROM AUTHOR]

Mirth is elicited by the perception of humor, which requires the resolution of an incongruity in an unexpected and playful manner. Previous psychophysiological research using affective pictures is scarce, and did not elucidate the cognitive and affective components of the humor process. In this study, the passive viewing paradigm is applied to mirthful, incongruent, neutral and erotic pictures to characterize the emotional response of mirth. Physiological (zygomaticus major [ZM] activity, skin conductance response [SCR] and heart rate [HR]), behavioral (free viewing time) and subjective responses (mirthful ratings) were recorded from 63 participants. The presence of an inflection change in the ZM response and mirthfulness ratings were used as markers of humor comprehension. Participants showed the greatest ZM and HR in response to mirthful compared to incongruent, erotic and neutral pictures, as well as a stronger SCR response to mirthful compared to incongruent and neutral pictures. The overall results shed light on the temporal course of the humor process, suggesting that humor comprehension (cognitive component) occurred around 1000–1500 ms after picture onset, according to the ZM and SCR responses; and the humor appreciation stage (emotional component) occurred at around 3500 ms after stimulus onset, according to the HR and SCR changes. Moreover, marked interindividual variability was observed in the number of smiles, and in the pictures that provoked them. This points to the complexity of the humor process, and suggests the need to develop methods to elicit mirth and elucidate the factors potentially underlying individual differences in humor. To characterize the emotional response of mirth, the passive viewing paradigm is applied to mirthful, incongruent, neutral and erotic pictures while recording physiological, behavioral and subjective responses. Our results showed increased zygomatic, heart rate and skin conductance responses to mirthful pictures. The latencies of these responses provide insight into the temporal course of the cognitive and emotional components of the humor process. [ABSTRACT FROM AUTHOR]

A central tenet of many theories of emotion is that emotional states are accompanied by distinct patterns of autonomic activity. However, experimental studies of coherence between subjective and autonomic responses during emotional states provide little evidence of coherence. Crucially, previous studies investigating coherence have either adopted univariate approaches or made limited use of multivariate analytic approaches by investigating subjective and autonomic responses separately. The current study addressed this question using a multivariate dimensional approach to build a common autonomic‐subjective affective space incorporating subjective responses and three different autonomic signals (heart rate, skin conductance response, and pupil diameter), measured during an emotion‐inducing task, in 51 participants. Results showed that autonomic and subjective responses could be adequately described in a two‐dimensional affective space. The first dimension included contributions from subjective and autonomic responses, indicating coherence, while contributions to the second dimension were almost exclusively of autonomic covariance. Thus, while there was a degree of coherence between autonomic and subjective emotional responses, there was substantial structure in autonomic responses that did not covary with subjective emotional experience. This study, therefore, contributes new insights into the relationship between subjective and autonomic emotional responses, and provides a framework for future multimodal emotion research, enabling both hypothesis‐ and data‐driven testing. Whether our subjective emotions are accompanied by distinct physiological states is hotly debated. Using a novel multivariate analysis enabling physiological data and subjective experience to be analysed within the same dimensional structure, we find evidence for both coherence between physiological markers of autonomic state and subjective experience, and evidence for a substantial degree of divergence. [ABSTRACT FROM AUTHOR]

Sensorimotor responses vary as a function of the cardiac cycle phase. These effects, known as cardiac cycle time effects, have been explained by the inhibition of cardiac afferent signals on information processing. However, the validity of cardiac cycle time effects is challenged by mixed findings. Factors such as current information processing and affective context may modulate cardiac cycle time effects and account for inconsistencies in the literature. The current study examines the influence of cardiac cycle time and threatening stimuli on two aspects of sensorimotor processing, response speed and inhibition. Thirty‐four participants (Mage = 19.35 years; 29 female) completed an auditory Go/No‐go task in no face, neutral face, and fearful face conditions. Faces were presented at either cardiac diastole or systole. Participants' reaction times (RTs) during Go trials and failures in response inhibition during No‐go trials were recorded. The ex‐Gaussian model was fit to RT data in each condition deriving the parameters, mu (μ) and tau (τ), that indicate response speed and attentional lapses, respectively. Repeated measures ANOVA were used to analyze behavioral data. Results showed that cardiac systole prolonged μ but decreased τ, and that cardiac diastole reduced inhibition errors in the fearful face condition but not in other conditions. These findings indicate that cardiac timing differentially modulates sensory‐perceptual and top‐down attentional processes and cardiac timing interacts with threatening contexts to influence response inhibition. These results highlight the specificity of cardiac cycle time effects on sensorimotor processing. Heart‐brain interactions represent the mind–body relationship‐a central question in psychology. Studies showed inconsistent cardiac timing effects on sensorimotor processing, due to the lack of differentiation of various cognitive aspects. Addressing this gap, we found that the cardiac timing of stimuli interacted with affective contexts to differentially modulate attention and response inhibition. These findings highlight the specificity of heart‐brain interactions. [ABSTRACT FROM AUTHOR]

Perseverative cognitions can provoke psychophysiological stress in the absence of an actual stressor and are considered important transdiagnostic vulnerability factors for several (mental) health issues. These stress‐related cognitive processes are reflected by both cognitive (assessed by self‐reports) and autonomic inflexibility (assessed by heart rate variability; HRV), with a key role attributed to the vagus nerve. Interestingly, modulation of the afferent branches of the vagus can be achieved with transcutaneous auricular vagus nerve stimulation (taVNS), a non‐invasive technique that employs a low‐intensity electrical current applied to the ear. In a sample of healthy individuals, we investigated the effects of taVNS of the left concha, compared to sham (earlobe) stimulation, on the cognitive and autonomic correlates of perseverative cognition following a psychosocial stress task. Interestingly, taVNS significantly reduced cognitive rigidity, reflected by reduced subjective perseverative thinking after psychosocial stress. Although there were no direct effects on autonomic correlates of perseverative cognition, individual differences in perseverative thinking after the stressor significantly affected the effects of taVNS on HRV. Specifically, more autonomic inflexibility during the stress task (i.e., reduced HRV) was associated with increases in perseverative thinking afterward for the sham condition, but not the active taVNS condition. Additional exploratory analyses revealed no significant moderation of stimulation intensity. Overall, the study findings endorse the association between perseverative cognitions and vagus nerve functioning. This study demonstrates that transcutaneous auricular vagus nerve stimulation (taVNS) significantly reduces perseverative thinking following psychosocial stress, which might be important information for the treatment of stress‐related mental health problems. Moreover, it provides evidence for the role of individual differences in perseverative thinking when examining the effects of taVNS on heart rate variability (HRV), an autonomic correlate of perseverative cognition. [ABSTRACT FROM AUTHOR]

Previous work has demonstrated the role of group‐based flow in group performance and experience, but the physiological correlates of these relations are largely unknown. We examined the relation between cardiovascular synchronization, self‐reported flow, and performance in a three‐person online gaming task. We included measures of Heart Rate (HR), Pre‐Ejection Period (PEP), and Cardiac Output (CO) as indices of task engagement and challenge (vs. threat) motivation. Group members were identifiable (i.e., visible) or anonymous during the game. Results indicated that PEP (as a marker of task engagement) and within‐group synchronization in PEP, predicted flow, and that synchronization in PEP mediated the relation between group performance and experienced flow. The anonymity vs. identifiability of group members did not play a role in these effects. Results are discussed in terms of implications for flow theory, group dynamics, and physiological synchrony. Successful cooperation in groups facilitates group performance and the experience of "flow" among group members. We show that both these outcomes relate to within‐group synchronization in pre‐ejection period (PEP), the extent to which cardiac contractility becomes similar across group members. [ABSTRACT FROM AUTHOR]

Fear and anxiety are crucial for adaptive responding in life‐threatening situations. Whereas fear is a phasic response to an acute threat accompanied by selective attention, anxiety is characterized by a sustained feeling of apprehension and hypervigilance during situations of potential threat. In the current literature, fear and anxiety are usually considered mutually exclusive, with partially separated neural underpinnings. However, there is accumulating evidence that challenges this distinction between fear and anxiety, and simultaneous activation of fear and anxiety networks has been reported. Therefore, the current study experimentally tested potential interactions between fear and anxiety. Fifty‐two healthy participants completed a differential fear conditioning paradigm followed by a test phase in which the conditioned stimuli were presented in front of threatening or neutral contextual images. To capture defense system activation, we recorded subjective (threat, US‐expectancy), physiological (skin conductance, heart rate) and visuocortical (steady‐state visual evoked potentials) responses to the conditioned stimuli as a function of contextual threat. Results demonstrated successful fear conditioning in all measures. In addition, threat and US‐expectancy ratings, cardiac deceleration, and visuocortical activity were enhanced for fear cues presented in threatening compared with neutral contexts. These results are in line with an additive or interactive rather than an exclusive model of fear and anxiety, indicating facilitated defensive behavior to imminent danger in situations of potential threat. Our research adds a new perspective on a potential interaction between fear and anxiety. We provide first evidence for enhanced defensive (fear) responses in potentially threatening (anxiety) contexts as indexed by multiple measures of defensive responding (perceived threat, HR, and EEG), suggesting that anxiety may facilitate fear responses rather than both emotional states being mutually exclusive. [ABSTRACT FROM AUTHOR]