Pupil dilation predicts individual self-regulation success across domains

The ventromedial prefrontal cortex plays an important role in implicit emotion regulation: A focality-optimized multichannel tDCS study in anxiety individuals

The regulation of emotions is a crucial facet of well-being and social adaptability, with explicit strategies receiving primary attention in prior research. Recent studies, however, emphasize the role of implicit emotion regulation, particularly implicating the ventromedial prefrontal cortex (VMPFC) in association with its implementation. This study delves into the nuanced role of the VMPFC through focality-optimized multichannel transcranial direct current stimulation (tDCS), shedding light on its causal involvement in implicit reappraisal. The primary goal was to evaluate the effectiveness of VMFPC-targeted tDCS and elucidate its role in individuals with high trait anxiety. Participants engaged in implicit and explicit emotion regulation tasks during multichannel tDCS targeting the VMPFC. The outcome measures encompassed negative emotion ratings, pupillary diameter, and saccade count, providing a comprehensive evaluation of emotion regulation efficiency. The intervention exhibited a notable impact, resulting in significant reductions in negative emotion ratings and pupillary reactions during implicit reappraisal, highlighting the indispensable role of the VMPFC in modulating emotional responses. Notably, these effects demonstrated sustained efficacy up to 1 day postintervention. This study underscores the potency of VMPFC-targeted multichannel tDCS in augmenting implicit emotion regulation. This not only contributes insights into the neural mechanisms of emotion regulation but also suggests innovative therapeutic avenues for anxiety disorders. The findings present a promising trajectory for future mood disorder interventions, bridging the gap between implicit emotion regulation and neural stimulation techniques.

Neural underpinnings of individual differences in emotion regulation: A systematic review

This review synthesises individual differences in neural processes related to emotion regulation (ER). It comprises individual differences in self-reported and physiological regulation success, self-reported ER-related traits, and demographic variables, to assess their correlation with brain activation during ER tasks. Considering region-of-interest (ROI) and whole-brain analyses, the review incorporated data from 52 functional magnetic resonance imaging studies. Results can be summarized as follows: (1) Self-reported regulation success (assessed by emotional state ratings after regulation) and self-reported ER-related traits (assessed by questionnaires) correlated with brain activity in the lateral prefrontal cortex. (2) Amygdala activation correlated with ER-related traits only in ROI analyses, while it was associated with regulation success in whole-brain analyses. (3) For demographic and physiological measures, there was no systematic overlap in effects reported across studies. In showing that individual differences in regulation success and ER-related traits can be traced back to differences in the neural activity of brain regions associated with emotional reactivity (amygdala) and cognitive control (lateral prefrontal cortex), our findings can inform prospective personalised intervention models.

Emotion regulation unveiled through the categorical lens of attachment

BACKGROUND

Emotion regulation, the process by which individuals manage and modify their emotional experiences, expressions, and responses to adaptively navigate and cope with various situations, plays a crucial role in daily life. Our study investigates the variations in emotion regulation strategies among individuals with different attachment styles (AS). Specifically, we examine how individuals with secure, anxious, avoidant, and fearful attachment styles effectively utilize cognitive reappraisal and expressive suppression to regulate their emotions.

METHODS

A total of n = 98 adults were instructed to attend, reappraise, or suppress their emotions while viewing negative and neutral images from the International Affective Picture System (IAPS) in an experimental emotion regulation task. After completing the task, participants rated the valence and arousal elicited by the images. Attachment styles were measured using the ECR-12 questionnaire and then categorized into four AS.

RESULTS

Our study revealed that individuals with secure AS (n = 39) effectively reduced displeasure through cognitive reappraisal but experienced levels of displeasure with expressive suppression. Anxious AS (n = 16) individuals successfully reduced displeasure using cognitive reappraisal but struggled to regulate arousal and effectively use expressive suppression. Avoidant AS (n = 24) individuals could reduce displeasure with both strategies but experienced high arousal during suppression attempts. Fearful AS (n = 19) individuals effectively regulated both displeasure and arousal using either strategy. However, Secure AS individuals showed superior reappraisal efficacy, significantly reducing arousal levels compared to the Fearful AS group. Both Secure and Avoidant AS groups experienced higher valence during reappraisal relative to a baseline, indicating a decrease in displeasure.

CONCLUSIONS

Individuals with different AS exhibit variations in the effectiveness of their use of emotion regulation strategies. Our findings reinforce the significance of AS in shaping emotion regulation processes and emphasize the need for tailored approaches to support individuals with different attachment orientations.

Effect of recurrent task-induced acute stress on task performance, vagally mediated heart rate variability, and task-evoked pupil response

Advances in wearable sensor technologies can be leveraged to investigate behavioral and physiological responses in task-induced stress environments. Reliable and valid multidimensional assessments are required to detect stress given its multidimensional nature. This study investigated the effect of recurrent task-induced acute stress on task performance, vagally mediated heart variability measures (vmHRV) and task-evoked pupillary response (TEPR). Task performance, vmHRV measures, and TEPR were collected from 32 study participants while they performed a computer-based task in a recurrent task-induced acute stress environment. Mixed-effects modeling was used to assess the sensitivity of each outcome variable to experimental conditions. Repeated measures correlation tests were used to examine associations between outcome variables. Task performance degraded under stress. vmHRV measures were lower in the stress conditions relative to the no stress conditions. TEPR was found to be higher in the stress conditions compared to the no stress conditions. Task performance was negatively associated with the vmHRV measures, and degraded task performance was linked to increased TEPR in the stress conditions. There were positive associations between vmHRV measures. TEPR was negatively associated with vmHRV measures. Although task-induced stress degrades task performance, recurrent exposure to that stress could alter this effect via habituation. Further, our findings suggest that vmHRV measures and TEPR are sensitive enough to quantify psychophysiological responses to recurrent task-induced stress.

Exploring eye-tracking data as an indicator of situational awareness in nursing students during a cardiorespiratory arrest simulation

AIM

To examine the components of visual attention that maintain situational awareness during simulation training in undergraduate nursing students with different instruction levels.

BACKGROUND

Eye-tracking can provide deep insight into the nurses' attention during simulated practice. Knowing which gaze patterns promote situational awareness can significantly improve nurse instruction.

DESIGN

A comparative observational study investigated the role of visual attention on the performance quality, psychophysiological parameters (vital signs, anxiety and stress) and socioemotional competencies (cognitive workload, motivation and self-efficacy) of nursing students with various experience levels.

METHODS

Thirty nursing students divided into two groups according to their academic level: first cycle (n=14) and second-cycle (n=16) faced a clinical simulation scenario to resolve a cardiorespiratory arrest event. Eye tracking-based analysis required the selection of six areas of interest. The monitorization of vital signs included measuring blood pressure, heart rate, respiratory rate and oxygen saturation before and after the simulation practice. Participants completed the socioemotional questionnaire (NASA-TLX). They answered the state subscale of the State-Trait Anxiety Inventory (STAI), the Visual Analogue Scale (VAS) of stress, the Situational Motivation Scale (SIMS) and the Baessler and Schwarzer General Self-Efficacy Scale.

RESULTS

The first-cycle group displayed higher vital sign scores than the second cycle, apart from the post-simulation respiratory rate. All physiological parameters increased in mean value after the clinical simulation, except oxygen saturation. Anxiety was the only parameter in the socioemotional domain to present a statistically significant difference between the groups. First-year nursing students showed greater anxiety, stress, mental workload, identified regulation and intrinsic motivation, while second-year students showed higher levels of amotivation, external regulation and perceived self-efficacy. Eye-tracking data (revisits, gaze and duration of fixations) exhibited statistically significant differences depending on the area of interest in both groups (p =. 05). The performance outcomes showed a negative and moderate association with gaze the total number of gazes in the second-cycle group (rho = -0.640, p = 0.010).

CONCLUSION

Eye-tracking-based analysis can help to predict performance quality while maintaining situational awareness during nursing instruction.

Phasic, Event-Related Transcutaneous Auricular Vagus Nerve Stimulation Modifies Behavioral, Pupillary, and Low-Frequency Oscillatory Power Responses

Transcutaneous auricular vagus nerve stimulation (taVNS) has been proposed to activate the locus ceruleus-noradrenaline (LC-NA) system. However, previous studies failed to find consistent modulatory effects of taVNS on LC-NA biomarkers. Previous studies suggest that phasic taVNS may be capable of modulating LC-NA biomarkers such as pupil dilation and alpha oscillations. However, it is unclear whether these effects extend beyond pure sensory vagal nerve responses. Critically, the potential of the pupillary light reflex as an additional taVNS biomarker has not been explored so far. Here, we applied phasic active and sham taVNS in 29 subjects (16 female, 13 male) while they performed an emotional Stroop task (EST) and a passive pupil light reflex task (PLRT). We recorded pupil size and brain activity dynamics using a combined Magnetoencephalography (MEG) and pupillometry design. Our results show that phasic taVNS significantly increased pupil dilation and performance during the EST. During the PLRT, active taVNS reduced and delayed pupil constriction. In the MEG, taVNS increased frontal-midline theta and alpha power during the EST, whereas occipital alpha power was reduced during both the EST and PLRT. Our findings provide evidence that phasic taVNS systematically modulates behavioral, pupillary, and electrophysiological parameters of LC-NA activity during cognitive processing. Moreover, we demonstrate for the first time that the pupillary light reflex can be used as a simple and effective proxy of taVNS efficacy. These findings have important implications for the development of noninvasive neuromodulation interventions for various cognitive and clinical applications.SIGNIFICANCE STATEMENT taVNS has gained increasing attention as a noninvasive neuromodulation technique and is widely used in clinical and nonclinical research. Nevertheless, the exact mechanism of action of taVNS is not yet fully understood. By assessing physiology and behavior in a response conflict task in healthy humans, we demonstrate the first successful application of a phasic, noninvasive vagus nerve stimulation to improve cognitive control and to systematically modulate pupillary and electrophysiological markers of the noradrenergic system. Understanding the mechanisms of action of taVNS could optimize future clinical applications and lead to better treatments for mental disorders associated with noradrenergic dysfunction. In addition, we present a new taVNS-sensitive pupillary measure representing an easy-to-use biomarker for future taVNS studies.

Parents regulate arousal while sharing experiences with their child: a study of pupil diameter change responses

Introduction

Parents provide their children with their first exposures to reciprocal shared experiences, and parental modeling of socio-emotional behaviors and regulatory responses largely influences their child's behavioral and neurological development. Some parental reactions are conscious, while others are non-volitional. This project aimed to explore parent-child pupil dilation change responses during shared interactions, specifically, whether parents' neuro-regulatory responses when sharing experiences with their child are different than responses of children interacting with their parents or children and adult peers sharing with each other.

Methods

To test this, four distinct interacting groups were recruited: (1) Parents sharing with their child; (2) Children sharing with their parent; (3) Children sharing with peers; and (4) Adults sharing with peers. All dyads engaged in a computerized shared imagery task, which facilitates communication and mental imagery during a shared experience. During the task, pupil diameter change was recorded as a measure of regulatory response.

Results

Findings highlight that parents sharing with their child have lower pupil diameter change than children sharing with their parents (p < 0.01), children sharing with peers (p < 0.01), and adults sharing with peers (p < 0.05), While no differences were seen between children sharing with parents, children sharing with peers or adults sharing with peers.

Discussion

Findings deepen the understanding of the neuroscience of parenting, by suggesting that parents, even of older children and adolescents, tend to regulate their arousal when interacting with their child, a response that proves to be unique compared to other dyad types for sharing experiences. Considering this dynamic, findings may direct future parent-led intervention methods to improve the child's socio-emotional development.

Pupillary motility responses to affectively salient stimuli in individuals with depression or elevated risk of depression: A systematic review and meta-analysis

Elaborative affective processing is observed in depression, and pupillary reactivity, a continuous, sensitive, and reliable indicator of physiological arousal and neurocognitive processing, is increasingly utilized in studies of depression-related characteristics. As a first attempt to quantitively summarize existing evidence on depression-related pupillary reactivity alterations, this review and meta-analysis evaluated the direction, magnitude, and specificity of pupillary indices of affective processing towards positively, negatively, and neutrally-valenced stimuli among individuals diagnosed with depression or with elevated risk of depression. Studies on pupillary responses to affective stimuli in the target groups were identified in PsycINFO and PubMed databases. Twenty-two articles met inclusion criteria for the qualitative review and 16 for the quantitative review. Three-level frequentist and Bayesian models were applied to summarize pooled effects from baseline-controlled stimuli-induced average changes in pupillary responses. In general, compared to non-depressed individuals, individuals with depression or elevated risk of depression exhibited higher pupillary reactivity (d =0.15) towards negatively-valenced stimuli during affective processing. Pupillary motility towards negatively-valenced stimuli may be a promising trait-like marker for depression vulnerability.

Using Task-Evoked Pupillary Response to Predict Clinical Performance during a Simulation Training

Training in healthcare skills can be affected by trainees' workload when completing a task. Due to cognitive processing demands being negatively correlated to clinical performance, assessing mental workload through objective measures is crucial. This study aimed to investigate task-evoked changes in pupil size as reliable markers of mental workload and clinical performance. A sample of 49 nursing students participated in a cardiac arrest simulation-based practice. Measurements of cognitive demands (NASA-Task Load Index), physiological parameters (blood pressure, oxygen saturation, and heart rate), and pupil responses (minimum, maximum, and difference diameters) throughout revealed statistically significant differences according to performance scores. The analysis of a multiple regression model produced a statistically significant pattern between pupil diameter differences and heart rate, systolic blood pressure, workload, and performance (R² = 0.280; F (6, 41) = 2.660; p < 0.028; d = 2.042). Findings suggest that pupil variations are promising markers to complement physiological metrics for predicting mental workload and clinical performance in medical practice.

An Easily Compatible Eye-tracking System for Freely-moving Small Animals

Measuring eye movement is a fundamental approach in cognitive science as it provides a variety of insightful parameters that reflect brain states such as visual attention and emotions. Combining eye-tracking with multimodal neural recordings or manipulation techniques is beneficial for understanding the neural substrates of cognitive function. Many commercially-available and custom-built systems have been widely applied to awake, head-fixed small animals. However, the existing eye-tracking systems used in freely-moving animals are still limited in terms of their compatibility with other devices and of the algorithm used to detect eye movements. Here, we report a novel system that integrates a general-purpose, easily compatible eye-tracking hardware with a robust eye feature-detection algorithm. With ultra-light hardware and a detachable design, the system allows for more implants to be added to the animal's exposed head and has a precise synchronization module to coordinate with other neural implants. Moreover, we systematically compared the performance of existing commonly-used pupil-detection approaches, and demonstrated that the proposed adaptive pupil feature-detection algorithm allows the analysis of more complex and dynamic eye-tracking data in free-moving animals. Synchronized eye-tracking and electroencephalogram recordings, as well as algorithm validation under five noise conditions, suggested that our system is flexibly adaptable and can be combined with a wide range of neural manipulation and recording technologies.

Investigating the relationship between background luminance and self-reported valence of auditory stimuli

The present study investigated the effect of background luminance on the self-reported valence ratings of auditory stimuli, as suggested by some earlier work. A secondary aim was to better characterise the effect of auditory valence on pupillary responses, on which the literature is inconsistent. Participants were randomly presented with sounds of different valence categories (negative, neutral, and positive) obtained from the IADS-E database. At the same time, the background luminance of the computer screen (in blue hue) was manipulated across three levels (i.e., low, medium, and high), with pupillometry confirming the expected strong effect of luminance on pupil size. Participants were asked to rate the valence of the presented sound under these different luminance levels. On a behavioural level, we found evidence for an effect of background luminance on the self-reported valence rating, with generally more positive ratings as background luminance increased. Turning to valence effects on pupil size, irrespective of background luminance, interestingly, we observed that pupils were smallest in the positive valence and the largest in negative valence condition, with neutral valence in between. In sum, the present findings provide evidence concerning a relationship between luminance perception (and hence pupil size) and self-reported valence of auditory stimuli, indicating a possible cross-modal interaction of auditory valence processing with completely task-irrelevant visual background luminance. We furthermore discuss the potential for future applications of the current findings in the clinical field.

Functional Coupling of the Locus Coeruleus Is Linked to Successful Cognitive Control

The locus coeruleus (LC) is a brainstem structure that sends widespread efferent projections throughout the mammalian brain. The LC constitutes the major source of noradrenaline (NE), a modulatory neurotransmitter that is crucial for fundamental brain functions such as arousal, attention, and cognitive control. This role of the LC-NE is traditionally not believed to reflect functional influences on the frontoparietal network or the striatum, but recent advances in chemogenetic manipulations of the rodent brain have challenged this notion. However, demonstrations of LC-NE functional connectivity with these areas in the human brain are surprisingly sparse. Here, we close this gap. Using an established emotional stroop task, we directly compared trials requiring response conflict control with trials that did not require this, but were matched for visual stimulus properties, response modality, and controlled for pupil dilation differences across both trial types. We found that LC-NE functional coupling with the parietal cortex and regions of the striatum is substantially enhanced during trials requiring response conflict control. Crucially, the strength of this functional coupling was directly related to individual reaction time differences incurred by conflict resolution. Our data concur with recent rodent findings and highlight the importance of converging evidence between human and nonhuman neurophysiology to further understand the neural systems supporting adaptive and maladaptive behavior in health and disease.

Eye Movement and Pupil Measures: A Review

Our subjective visual experiences involve complex interaction between our eyes, our brain, and the surrounding world. It gives us the sense of sight, color, stereopsis, distance, pattern recognition, motor coordination, and more. The increasing ubiquity of gaze-aware technology brings with it the ability to track gaze and pupil measures with varying degrees of fidelity. With this in mind, a review that considers the various gaze measures becomes increasingly relevant, especially considering our ability to make sense of these signals given different spatio-temporal sampling capacities. In this paper, we selectively review prior work on eye movements and pupil measures. We first describe the main oculomotor events studied in the literature, and their characteristics exploited by different measures. Next, we review various eye movement and pupil measures from prior literature. Finally, we discuss our observations based on applications of these measures, the benefits and practical challenges involving these measures, and our recommendations on future eye-tracking research directions.

A Bridge between the Breath and the Brain: Synchronization of Respiration, a Pupillometric Marker of the Locus Coeruleus, and an EEG Marker of Attentional Control State

Yogic and meditative traditions have long held that the fluctuations of the breath and the mind are intimately related. While respiratory modulation of cortical activity and attentional switching are established, the extent to which electrophysiological markers of attention exhibit synchronization with respiration is unknown. To this end, we examined (1) frontal midline theta-beta ratio (TBR), an indicator of attentional control state known to correlate with mind wandering episodes and functional connectivity of the executive control network; (2) pupil diameter (PD), a known proxy measure of locus coeruleus (LC) noradrenergic activity; and (3) respiration for evidence of phase synchronization and information transfer (multivariate Granger causality) during quiet restful breathing. Our results indicate that both TBR and PD are simultaneously synchronized with the breath, suggesting an underlying oscillation of an attentionally relevant electrophysiological index that is phase-locked to the respiratory cycle which could have the potential to bias the attentional system into switching states. We highlight the LC’s pivotal role as a coupling mechanism between respiration and TBR, and elaborate on its dual functions as both a chemosensitive respiratory nucleus and a pacemaker of the attentional system. We further suggest that an appreciation of the dynamics of this weakly coupled oscillatory system could help deepen our understanding of the traditional claim of a relationship between breathing and attention.