Comparison between the Effects of Acute Physical and Psychosocial Stress on Feedback-Based Learning.

Stress modulates feedback-based learning, a process that has been implicated in declining mental function in aging and mental disorders. While acute physical and psychosocial stressors have been used interchangeably in studies on feedback-based learning, the two types of stressors involve distinct physiological and psychological processes. Whether the two types of stressors differentially influence feedback processing remains unclear. The present study compared the effects of physical and psychosocial stressors on feedback-based learning. Ninety-six subjects (Mage = 19.11 years; 50 female) completed either a cold pressor task (CPT) or mental arithmetic task (MAT), as the physical or psychosocial stressor, while electrocardiography and blood pressure were measured to assess cardiovascular stress reactivity (CVR). Self-ratings on the emotional valence of the stressors were also obtained. A probabilistic learning task was given prior to and after the stressors. Accuracy in selecting positive (Go accuracy) and avoiding negative stimuli (No-go accuracy) were recorded as learning outcomes. Repeated measures ANOVA and multiple regressions were used to compare the effects of two stressors and examine the effects of CVR and valence on the learning outcomes. The results showed that although the effects of CPT and MAT on feedback processing were not different, CVR and valence influenced Go and No-go accuracy, respectively. The results suggest that stress-modulated feedback-based learning involves multiple pathways and underscore the link between CVR and reward sensitivity. The findings have clinical implications and may contribute to a better understanding of human behavioral systems.

Participant diversity in Psychophysiology.

The Society for Psychophysiological Research and accompanying journal, Psychophysiology, have increasingly incorporated diversity and inclusion into their posted values, conference programming, and science. Much of this focus on equity, diversity, and inclusion work has occurred since 2010. The current review content analyzed the articles published in Psychophysiology from 2010 through 2020 to determine if SPR and Psychophysiology's commitment to diversity and inclusion has resulted in changes to reporting and analysis of participant demographics. Demographic reporting practices were compared to APA reporting standards and the use of demographic variables assessed according to the guidance proffered in the introduction to Psychophysiology's 2016 Special Issue on Diversity and Representation. Results of the content analysis indicated near perfect reporting of biological sex and frequent reporting of average age. Age range and educational attainment were reported in over half of studies, while race or ethnicity were reported in only 17%. Socioeconomic status, income, gender identity, and sexual orientation were almost never reported. In over 60% of studies at least one major demographic variable was reported, but was not used in preliminary, main, or supplementary analyses as a covariate, moderator, or otherwise. SPR and Psychophysiology should continue advocating for increased reporting of major demographic variables and ethical analysis of demographic modulation of various psychophysiological mechanisms. We provide a preliminary template of reporting standards and call for the inclusion of more open science practices by psychophysiologists.

How Long Is Long Enough? Controlling for Acute Caffeine Intake in Cardiovascular Research.

Caffeine substantially affects cardiovascular functioning, yet wide variability exists in caffeine control procedures in cardiovascular reactivity research. This study was conducted in order to identify a minimal abstention duration in habitual coffee consumers whereby cardiovascular reactivity is unconfounded by caffeine; Six hours (caffeine's average half-life) was hypothesized. Thirty-nine subjects (mean age: 20.9; 20 women) completed a repeated measures study involving hand cold pressor (CP) and memory tasks. Caffeinated and decaffeinated coffee were administered. The following cardiovascular indices were acquired during pre-task, task, and post-task epochs prior to coffee intake, 30 min-, and six hours post-intake: Heart rate (HR), high-frequency heart rate variability (HF-HRV), root mean squared successive differences (RMSSD), systolic and diastolic blood pressures (SBP, DBP), mean arterial pressure (MAP), pre-ejection period (PEP), left ventricular ejection time (LVET), systemic vascular resistance (SVR), systemic vascular resistance index (SVRI). Results support the adequacy of a six-hour abstention in controlling for caffeine-elicited cardiovascular changes. The current study offers a suggested guideline for caffeine abstention duration in cardiovascular research in psychophysiology. Consistent practice in caffeine abstention protocols would promote validity and reliability across such studies.

Cardiac timing and threatening stimuli influence response inhibition and ex-Gaussian parameters of reaction time in a Go/No-go task.

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.

"Generalized unsafety" as fear inhibition to safety signals in adults with and without childhood trauma.

The Generalized Unsafety Theory of Stress posits that low heart rate variability contributes to a perception of "generalized unsafety" (i.e., constantly perceiving oneself to be unsafe), independent of stressful events or stress-related symptomatology. We tested this claim by examining if resting heart rate variability, trait worry, posttraumatic stress symptoms, trauma history, and age of onset predicted fear inhibition, a measure of generalized unsafety. A Pavlovian discriminant conditioning paradigm was used to assess fear inhibition level by comparing eyeblink startle potentiation to a threat cue (presented with air blast) with startle potentiation to a safety signal (never presented with air blast). Survey and laboratory responses were collected from 42 adults who were 20 years old on average, 86% Women, and 76% White. Heart rate variability did not independently predict variation in fear inhibition, as hypothesized. Rather, higher levels of posttraumatic stress symptoms and greater cumulative interpersonal trauma predicted lower fear inhibition. Individuals reporting childhood trauma had higher trait worry, which predicted more severe posttraumatic stress symptoms. These findings highlight the role of attenuated inhibitory learning in stress-related symptomatology and developmentally disruptive trauma. Ability to distinguish threat from safety is a plausible biobehavioral mechanism by which adversity impacts development.

Comparison of Functional Connectivity in the Prefrontal Cortex during a Simple and an Emotional Go/No-Go Task in Female versus Male Groups: An fNIRS Study.

Inhibitory control is a cognitive process to suppress prepotent behavioral responses to stimuli. This study aimed to investigate prefrontal functional connectivity during a behavioral inhibition task and its correlation with the subject's performance. Additionally, we identified connections that are specific to the Go/No-Go task. The experiment was performed on 42 normal, healthy adults who underwent a vanilla baseline and a simple and emotional Go/No-Go task. Cerebral hemodynamic responses were measured in the prefrontal cortex using a 16-channel near infrared spectroscopy (NIRS) device. Functional connectivity was calculated from NIRS signals and correlated to the Go/No-Go performance. Strong connectivity was found in both the tasks in the right hemisphere, inter-hemispherically, and the left medial prefrontal cortex. Better performance (fewer errors, faster response) is associated with stronger prefrontal connectivity during the simple Go/No-Go in both sexes and the emotional Go/No-Go connectivity in males. However, females express a lower emotional Go/No-Go connectivity while performing better on the task. This study reports a complete prefrontal network during a simple and emotional Go/No-Go and its correlation with the subject's performance in females and males. The results can be applied to examine behavioral inhibitory control deficits in population with neurodevelopmental disorders.

Only time will tell: Acute stress response patterns with time series analysis.

Acute stress is often conceptualized as a response pattern that activates the fight-or-flight response via the sympathetic nervous system (SNS). However, other stress response patterns can manifest as well, such as parasympathetic nervous system (PNS) shutdown, and SNS-PNS coactive hypervigilance. Each response pattern engages many dimensions, including physiological, emotional, and behavioral. As stress unfolds over time, these patterns can change to adjust to the changing nature of the stressor. This proof of concept study introduces novel time series methodology to track the multidimensional patterns of acute stress. The defense cascade provides a model with which to understand and predict response patterns over the time course of an acute stressor. The time series methodology introduced in this study holds promise for identifying mechanisms of change in therapy and clinical settings.

Resting heart rate variability modulates the effects of concurrent working memory load on affective startle modification.

Vagally mediated heart rate variability (vmHRV) is thought to index top-down control processes in emotion regulation. According to the Generalized Unsafety Theory of Stress (GUTS), resting vmHRV indexes top-down resources that are needed to inhibit subcortical threat circuits, which is important for context-appropriate affective responding. Although this notion has been supported by studies of affective startle (SR) modification, direct evidence that top-down resources are the linking mechanism between vmHRV and context-appropriate affective responding has been lacking. To investigate this possible mechanism, college-aged participants (n = 92) were recruited to complete a picture viewing task and a concurrent working memory (WM) task. Concurrent WM load was manipulated, and the auditory SR stimulus was delivered while viewing affective pictures. Electrocardiography and electromyography were recorded to assess vmHRV and SR eyeblink, respectively. Results showed that WM load attenuated affective SR modification. As expected, the attenuating effects of load on affective SR modification were stronger among low vmHRV relative to high vmHRV individuals, indicating that vmHRV is linked to context-appropriate affective responding through the mechanism of top-down resources. These results support the GUTS and suggest that atypical affective responding among low vmHRV individuals is attributed to the lack of WM resources. Our findings highlight the relation between vmHRV and top-down resources that have been implicated in emotion regulation and contribute to a better understanding of emotion dysregulation in psychopathology.

Interplay between state anxiety, heart rate variability, and cognition: An ex-Gaussian analysis of response times.

The present study employed an ex-Gaussian model of response times (RTs) to elucidate the cognitive processes related to experimentally induced state anxiety (SA) and vagally mediated heart rate variability (vmHRV), an indicator of adaptive responses in both cognitive and affective domains. Participants (n = 110) completed a dual task composed of (i) a flanker attention and (2) working memory load task, while SA was induced by threat of noise. Electrocardiography was measured during the dual task and during four baseline periods in order to calculate vmHRV. RTs on the flanker task were fit to an ex-Gaussian distribution, which estimated three RT parameters: mu (Gaussian mean), sigma (Gaussian SD), and tau (combination of exponential mean and SD). First, findings indicate that threat of noise was associated with reductions in mu and tau, suggesting that SA might improve attention and motor responding. Second, higher resting vmHRV was associated with lower tau (averaged across conditions) and stronger threat-related decreases in tau. Third, intra-individual decreases in vmHRV were accompanied by concomitant decreases in tau. These findings support roles for trait and state vagal control in guiding adaptive anxiety-related (and anxiety-unrelated) attentional responses. Findings are consistent with extant theories that emphasize functional interrelations among emotion, cognition, and vagal function.

Probing Neurovisceral Integration via Functional Near-Infrared Spectroscopy and Heart Rate Variability.

The neurovisceral integration model (NVM) proposes that an organism's ability to flexibly adapt to its environment is related to biological flexibility within the central autonomic network (CAN). One important aspect of this flexibility is behavioral inhibition (Thayer and Friedman, 2002). During a behavioral inhibition task, the CAN, which comprises a series of feedback loops, must be able to integrate information and react to these inputs flexibly to facilitate optimal performance. The functioning of the CAN is shown to be associated with respiratory sinus arrhythmia (RSA), as the vagus nerve is part of this feedback system. Although the NVM has been examined through neural imaging and RSA, only a few studies have examined these measures simultaneously during the neuroimaging procedure. Furthermore, these studies were done at rest or used tasks that were not targeted at processes associated with the NVM, such as behavioral inhibition and cognitive flexibility. For this reason, the present study assessed RSA and neural activation in the pre-frontal cortex simultaneously while participants completed a behavior inhibition task. RSA and functional near-infrared spectroscopy were collected in 38 adults, and resting levels of pre-frontal activation were negatively related to RSA, but pre-frontal activation during the behavior inhibition task was not. The negative relationship between RSA and oxygenated hemoglobin is consistent with previous functional magnetic resonance imaging work examining the NVM at baseline and should be further studied. Additional research investigating how this relationship may change based on task demands or environmental contexts would help clarify the applicability of the model.

Restricted repetitive behaviors in autism spectrum disorder: A systematic review from the neurovisceral integration perspective.

The neurovisceral integration model posits that cognitive-behavioral inflexibility arises from biological inflexibility of feedback loops within the central autonomic network. The parasympathetic nervous system (PNS) is integral in this network. Activity of the PNS, which is normally tonically inhibited, can be indexed through respiratory sinus arrhythmia (RSA). When the PNS becomes disinhibited, indicating decreased flexibility within the network, RSA is reduced and cognitive-behavioral flexibility is impaired. Using this theoretical framework, cognitive-behavioral inflexibility is discussed from the Research Domain Criteria (RDoC) perspective. Restricted repetitive behaviors in autism spectrum disorder (ASD) are proposed as exemplars of cognitive-behavioral inflexibility, and behavioral and RSA literature in ASD are reviewed. RSA differences and their relation to inflexibility in ASD are discussed to support the model and to propose RSA as a biomarker for cognitive-behavioral inflexibility. Considerations for future research are discussed, in addition to implications the model might have on assessment and transdiagnostic treatment practices.

Autonomic response in autism spectrum disorder: Relationship to social and cognitive functioning.

Individuals with autism spectrum disorder (ASD) may exhibit chronic autonomic nervous system (ANS) hyperarousal (e.g., lower respiratory sinus arrhythmia and higher heart rate) compared to their typically developing peers, reflecting a chronic biological threat response. The sustained nature of this cardiac threat suggests tonic nervous system perception of threat in safe contexts. Herein, the cardiac literature in adult and child populations with ASD is reviewed and placed within a continuum of functioning in order to inform the relationship between cardiac response and functioning in ASD. Findings from this review support the relationship between chronic autonomic hyperarousal and emotional and behavioral difficulties observed in individuals with ASD.

Physiological feelings.

The role of peripheral physiology in the experience of emotion has been debated since the 19th century following the seminal proposal by William James that somatic responses to stimuli determine subjective emotion. Subsequent views have integrated the forebrain's ability to initiate, represent and simulate such physiological events. Modern affective neuroscience envisions an interacting network of "bottom-up" and "top-down" signaling in which the peripheral (PNS) and central nervous systems both receive and generate the experience of emotion. "Feelings" serves as a term for the perception of these physical changes whether emanating from actual somatic events or from the brain's representation of such. "Interoception" has come to represent the brain's receipt and representation of these actual and "virtual" somatic changes that may or may not enter conscious awareness but, nonetheless, influence feelings. Such information can originate from diverse sources including endocrine, immune and gastrointestinal systems as well as the PNS. We here examine physiological feelings from diverse perspectives including current and historical theories, evolution, neuroanatomy and physiology, development, regulatory processes, pathology and linguistics.

Controlling for caffeine in cardiovascular research: A critical review.

Caffeine, the most widely consumed drug in the world, exerts numerous effects on cardiovascular activity. Thus, it is important and advisable to control for caffeine consumption in studies examining caffeine and/or cardiovascular activity and reactivity. This paper 1) reviews the literature concerning caffeine's effects on cardiovascular parameters; 2) summarizes the widely varying protocols used to control for the drug in extant cardiovascular literature, and 3) provide guidelines for caffeine control procedures to minimize potentially confounding acute and withdrawal effects of the drug. An abstention period equal to the average half-life of the drug is recommended for creation of methodological controls for caffeine. Additional methodological recommendations are described concerning factors that moderate the half-life of caffeine. When feasible, researchers should consider and aim to control for caffeine's acute and extended psychophysiological effects. This understudied issue has fundamental implications for caffeine-related investigations and research in psychophysiology and behavioral medicine.

Exteroceptive stimuli override interoceptive state in reaction time control.

The processing of reaction time (RT) stimulus is modulated by its timing relative to the cardiac cycle. RT stimulus processing is also influenced by task-irrelevant stimuli: a sensory stimulus speeds RT when it accompanies a cue to react in another sensory modality. Different theories have been proposed to explain this accessory stimulus effect (ASE). However, it is unclear whether the ASE interacts with the cardiac timing effect. In the present study, the relationship of the ASE, cardiac timing, and stimulus valence was examined. Fifty-two subjects performed 400 trials of a simple RT task. Images of neutral and fear faces served as visual accessory stimuli; the RT stimulus was a 75 dB tone. Electrocardiography was recorded. Visual and auditory stimuli were presented at either cardiac systole or diastole. The stimulus onset asynchrony between visual and auditory stimuli was either 0 or 75 ms. Repeated measures ANOVAs showed that cardiac timing modulated RT, but only when accessory stimuli were absent. RT was shorter when the accessory stimulus preceded the imperative stimulus with respect to simultaneous presentation. The ASE was not influenced by visual stimulus valence or cardiac timing. Results indicate that the ASE overrides cardiac timing effects, suggesting a dynamic balance between exteroceptive stimuli and interoceptive states, and highlight the importance of embodied information processing.

Autonomic specificity in emotion: The induction method matters.

Research on the autonomic specificity of emotion has spanned decades, yet the findings of this research are still highly debated. Although many studies have explored the autonomic specificity of emotions, few have concurrently explored the influence by which the induction methods themselves have had in directing autonomic change. The current study was conducted to assess whether the methods for emotion elicitation could be meaningfully captured by multivariate pattern classification techniques that have been previously used to explore autonomic specificity of emotion. This aim was achieved by using three separate emotion-elicitation methods to elicit five separate emotions. A sample of 64 college-aged students watched film clips, read imagery scripts, and recalled personal memories for five emotion states. Using multivariate pattern classification analysis, the evidence from the current study lends further support for autonomic specificity of emotion, but also highlights the role that the specific induction technique contributes to autonomic changes that accompany emotions in the laboratory.

Respiratory Sinus Arrhythmia Predicts Restricted Repetitive Behavior Severity.

In addition to social communication deficits, restricted repetitive behaviors (RRBs) are a key diagnostic feature of autism spectrum disorder (ASD). Dysfunction of the autonomic nervous system (ANS) in ASD has been posited as a mechanism of RRBs; however, most studies investigating ANS activity in ASD have focused on its relation to social functioning. This study used respiratory sinus arrhythmia (RSA) patterns to measure ANS functioning and analyze its relation to RRBs in children with and without an ASD diagnosis. Baseline RSA and RSA reactivity predicted RRB severity and exploratory analyses revealed these measures may be associated with RRB subgroups. These results are discussed in regards to the behavioral literature on RRBs and the benefits of finding biomarkers for these behaviors.

A Little Goes a Long Way: Low Working Memory Load Is Associated with Optimal Distractor Inhibition and Increased Vagal Control under Anxiety.

Anxiety impairs both inhibition of distraction and attentional focus. It is unclear whether these impairments are reduced or exacerbated when loading working memory with non-affective information. Cardiac vagal control has been related to top-down regulation of anxiety; therefore, vagal control may reflect load-related inhibition of distraction under anxiety. The present study examined whether: (1) the enhancing and impairing effects of load on inhibition exist together in a non-linear function, (2) there is a similar association between inhibition and concurrent vagal control under anxiety. During anxiogenic threat-of-noise, 116 subjects maintained a digit series of varying lengths (0, 2, 4, and 6 digits) while completing a visual flanker task. The task was broken into four blocks, with a baseline period preceding each. Electrocardiography was acquired throughout to quantify vagal control as high-frequency heart rate variability (HRV). There were significant quadratic relations of working memory load to flanker performance and to HRV, but no associations between HRV and performance. Results indicate that low load was associated with relatively better inhibition and increased HRV. These findings suggest that attentional performance under anxiety depends on the availability of working memory resources, which might be reflected by vagal control. These results have implications for treating anxiety disorders, in which regulation of anxiety can be optimized for attentional focus.