Pupil size is a well-established marker of the level of cognitive effort, with greater efforts leading to larger pupils. This is particularly true for pupil size during task performance itself, whereas findings on anticipatory effort triggered by a cue stimulus are less consistent. For example, a recent report by Frömer et al. (2021) found that in a cued Stroop task, behavioural performance and electrophysiological markers of preparatory effort allocation were modulated by cued reward and ‘efficacy’ (the degree to which rewards depended on good performance), but pupil size did not show a comparable pattern. Here, we conceptually replicated this study in a pupillometry study. In line with previous findings, we found no modulation of absolute pupil size in the cue-to-target interval. Instead, we observed a significant difference in the rate of pupil dilation in anticipation of the target: Pupils dilated more rapidly for high-reward trials in which rewards depended on good performance. This was followed by a significant difference in absolute pupil size within the first hundreds of milliseconds following Stroop stimulus onset, likely reflecting a lagging effect of anticipatory effort allocation. Finally, the slope of pupil dilation was significantly correlated with behavioural response times, and this association was strongest for the high-reward, high-efficacy trials, further supporting that the rate of anticipatory pupil dilation reflects anticipatory effort. We conclude that pupil size is modulated by anticipatory effort, but in a highly temporally-specific manner, which is best reflected by the rate of dilation in the moments just prior to stimulus onset.

In everyday conversation, bilingual individuals switch between languages not only in reaction to monolinguals with different language profiles but also voluntarily and naturally. However, whether and how various switching contexts dynamically modulate the domain-general control were still illusive. Using a cross-task paradigm which flanker task was interleaved with language switching task trial-by-trial, the present study manipulated forced, voluntary and natural switching contexts. A group of unbalanced Chinese-English bilinguals performed a flanker task in the three switching contexts. The results showed that the cross-domain interaction on the P3 effect revealed an atypical flanker effect in forced switching contexts only, and P3 amplitude of incongruent trials in forced switching contexts was smaller than both natural and voluntary switching contexts. Furthermore, the robust brain-brain and brain-behavior relationships between language control and domain-general control were significantly emerged in the forced switching context only. Altogether, our findings support the dynamic adaptation of language control to cognitive control and highlight the importance of switching contexts.

The aperiodic slope of the EEG power spectrum (characterized by a 1/fx distribution in which power decreases as frequency increases) is hypothesized to index the excitatory-inhibitory balance and has been associated with various neurodevelopmental outcomes in older children and adults. However, the dearth of research early in development led us to investigate associations among EEG aperiodic slope, temperament, and maternal internalizing (anxiety and depression) symptoms in a large cohort of typically developing infants. Steeper slope was associated with higher scores on the temperament domains of orienting/regulation and surgency but was not associated with negative affectivity. Maternal symptoms did not appear to be directly associated with slope, but slope moderated the association between maternal symptoms and temperament. Specifically, steeper slope was associated with a stronger negative association between maternal internalizing symptoms and infant orienting/regulation. These results demonstrate associations between slope and behavior as early as infancy, which may reflect early differences in the development of global inhibitory networks. Longitudinal research in early childhood is necessary to better understand the nature of these relations during development and their potential impact on later socioemotional outcomes.

It is commonly agreed that power modulations in alpha oscillatory activity serve as an inhibitory neural mechanism, selectively routing information within neural circuits. In visuo-spatial attention, alpha oscillations enhance the processing of relevant targets and suppress potential distractors. However, there are inconsistencies regarding alpha power modulations with increasing load in common working memory (WM) tasks. Particularly, high WM load is associated with either decreased or increased alpha power, depending on the type of WM task deployed (i.e., N-back vs. Sternberg task). Next to existing cognitive interpretations of this variation of alpha power with load, recent considerations suggest the involvement of oculomotor action as a complementary explanation. In the present report we attempt to test this complementary view. We will conduct a large-scale combined electroencephalography and eye tracking study with 120 participants to examine the relationship between alpha power modulation and oculomotor action in the context of an N-back task and a Sternberg task. We aim to explore whether different gaze patterns during these tasks offer explanatory value in addressing the variations in alpha power with WM load. To this end, statistical tests on scalp-level power for the alpha band (8-14 Hz) and gaze deviation metrics will be conducted.

Visual search is guided by mental representations of target-defining features (attentional templates) that are activated in a preparatory fashion. It remains unknown how many templates can be maintained concurrently, and what kind of costs are associated with multiple-template versus single-template search. Here, we compared the operation of attentional templates during three-colour and single-colour search tasks. Preparatory template activation processes were tracked by measuring N2pc components to task-irrelevant singleton colour probes that appeared in rapid succession during the interval between search displays. These probes attract attention (as indexed by an N2pc) if the corresponding colour template is active at the time when the probe appears. In a three-colour search task where target identity was fully predictable (Experiment 1), only probes that matched the upcoming target colour triggered N2pcs, demonstrating that only a single target template was activated. When three possible colour targets appeared randomly and unpredictably (Experiment 2), probes that matched any of these colours triggered N2pcs, demonstrating that all three templates were activated concurrently. However, relative to a single-colour search task, clear costs emerged in this three-colour task for the attentional guidance towards search targets and for search performance. These costs appear to be linked to inhibitory interactions between simultaneously active search templates. These findings show that while at least three target templates can be maintained in parallel, multiple-template search is still subject to capacity limitations which affect both template-guided attentional guidance and the subsequent selective processing of search targets.

Research has shown that exposure to higher rates of neighborhood disadvantage and contextual threat increases risk for the development of psychopathology in youth, with some evidence that these effects may differ across racial/ethnic groups. Although studies have shown that direct exposure to stress impacts neural responses to threat-relevant stimuli, less is known about how neighborhood characteristics more generally (e.g., living in neighborhood characterized by high crime risk, whether or not the individual directly experiences any crime) may impact children’s neural responses to threat. To address this question, we examined links between census-derived indices of neighborhood crime and neural reactivity to emotional stimuli in a sample of 100 children (Mage = 9.64, 54% girls, 65% non-Hispanic White) and whether these relations differ for children from minority backgrounds compared to non-Hispanic White children. Focusing on the late positive potential (LPP) event-related potential (ERP) component, we examined neural reactivity to threat-relevant stimuli (fearful faces) as well as non-threat relevant negative (sad faces) and positive (happy faces) stimuli across low, medium, and high intensities (morph levels). We found that levels of neighborhood crime were associated with LPP response to high intensity fearful, but not happy or sad, faces, but only among children from racial/ethnic minority backgrounds. This suggests that levels of crime within one’s neighborhood may be a more salient stressor for children from minority racial-ethnic groups than for non-Hispanic White children.

This study examined neural signatures associated conflict-monitoring, recognition and feedback processing in a novel feedback Concealed Information Test (fCIT), and also examined whether all the ERPs can be used to detect concealed autobiographical information. Participants were randomly assigned to one of two groups (guilty or innocent) and then tested in the fCIT while undergoing electroencephalograms (EEGs). Results show that the probe (participants’ name) elicited more negative N200, more positive recognition P300 than irrelevants among guilty participants, and feedback following the probe elicited a larger feedback P300 than feedback following irrelevants. Further, we found that all indicators, including conflict-monitoring N200, recognition P300, and feedback P300, could significantly discriminate between guilty and innocent participants. Combining them is highly effective in discriminating between guilty and innocent participants (AUC = 0.96). These findings not only shed light on the neural processing of fCIT, but also suggest the potential of using fCIT to detect concealed autobiographical information.

Motivation is considered a crucial factor in determining emotion regulation choice (ER choice). Our previous study revealed that increased motivation led to a preference for distraction over reappraisal due to the narrowed attention, yet neural underpinnings supporting this phenomenon remain unclear. In this study, we used event-related potentials (ERPs) to investigate whether motivation influences ER choice by early attention processing (P2) or late resource engagement (LPP). EEG activities were recorded for the pictorial contexts varying in motivational intensity and direction, while participants (N=68) were required to decide which strategy from the two options they would use to regulate their emotions. Consistent with previous studies, the results indicated that individuals chose more distraction over reappraisal in high-withdrawal motivated contexts while a reversed pattern was observed in low-withdrawal motivated contexts. Moreover, high-intensity motivated emotional contexts result in enhanced P2 and LPP. Further analysis indicates that only frontal P2 and the early LPP mediate the effect of motivational intensity on ER choice. These findings suggest that heightened motivation leads to a preference for distraction over reappraisal during emotion regulation due to the greater occupation of attentional resources.

Imaginal exposure is a standard procedure of cognitive behavioural therapy for the treatment of anxiety and panic disorders. It is often used when in vivo exposure is not possible, too stressful for patients, or would be too expensive. The Bio-Informational Theory implies that imaginal exposure is effective because of the perceptual proximity of mental imagery to real events, whereas empirical findings suggest that propositional thought of fear stimuli (i.e., thinking about the stimuli without seeing them in the mind’s eye) could be sufficient. To investigate whether mental imagery or propositional thought is crucial for the success of imaginal exposure, participants with the rare state of aphantasia (= absence of sensory mental imagery) and two control groups were subjected to a fear conditioning paradigm followed by imaginal exposure and a reinstatement procedure. During imaginal exposure, a control group (N = 30) stared at a bright screen to disrupt visual imagery by incoming luminance (= simulated aphantasia), while a second control group (N = 30) and participants with actual aphantasia (N = 30) kept their eyes closed. Results showed successful extinction in all groups, thus demonstrating that imaginal extinction is possible using propositional thought. Moreover, results indicate that people with aphantasia experience less emotional distress during the fear conditioning procedure, most likely due to similar mechanisms as in alexithymia, i.e., a decoupling between physiological arousal and emotional experience.

There is considerable evidence documenting associations between tobacco smoking, including initiation, maintenance, and relapse of addiction, with diminished cardiovascular responses to acute psychological stress. However, less is known about how smokers respond to repeated stress across time. The current study examined patterns of cardiovascular reactivity and adaptation to recurrent stress among abstinent smokers, smokers who continued to smoke at their normal rate, and non-smokers. Smokers were randomly assigned to one of two conditions; ad libitum (n = 42), or 24h abstinence (n = 61); and non-smokers (n = 43) provided comparative referencing. Across the two laboratory sessions, participants (n = 149) were asked to complete a modified version of the trier social stress test (TSST), while monitoring systolic and diastolic blood pressure, and heart rate activity. Results showed that while non-smokers had elevated cardiovascular reactivity to begin with, they showed a greater capacity to habituate to recurrent stress across sessions. The data also suggest that smokers displayed attenuated cardiovascular reactivity to acute psychological stress and showed little habituation to repeated stress. In adjusted models, smokers exhibited less systolic blood pressure tolerance to stress. This poorer response profile in smokers may be a potential mechanism that leads to further cardiotoxic effects on health. Key words: Smoking, cardiovascular reactivity, habituation, stress

For distinguished contributions to psychophysiology: Christopher J. Patrick

The neurovisceral integration model proposes that information flows bidirectionally between the brain and the heart via the vagus nerves and vagally-mediated heart rate variability (vmHRV) can be used to index heart-brain interaction. Recent research has shown that voluntary reduction of breathing rate (slow-paced breathing, SPB) can enhance cardiac vagal control. Additionally, prefrontal transcranial direct current stimulation (tDCS) can modulate the excitability of the prefrontal region and influence the vagus nerve. However, fundamental research on the combination of SPB and prefrontal tDCS to increase vmHRV and other physiological indices of the autonomic nervous system is scarce. Therefore, 200 healthy participants were assigned to four experimental groups. Each group received either 20 min of active or sham tDCS combined with 5.5 breath per minute (BPM) or 15 BPM breathing. Regardless of the tDCS condition, the SPB group showed a significant increase in vmHRV over 20 minutes, suggesting an increase in parasympathetic activity. In addition, a significant decrease in HR at the first and second 5-minute epochs of the intervention. Regardless of breathing condition, the active tDCS group exhibited higher HR at the fourth 5-minute epoch of the intervention compared to the sham tDCS group, suggesting more sympathetic arousal. However, there was no combined effect on vmHRV, HR, skin conductance, or blood pressure. 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 top-down and bottom-up approaches can be combined to improve vagal control.

According to the arousal model of vigilance, the locus coeruleus-norepinephrine (LC-NE) system modulates sustained attention over long periods by regulating physiological arousal. Recent research has proposed that transcutaneous auricular vagus nerve stimulation (taVNS) modulates indirect physiological markers of LC-NE activity, although its effects on vigilance have not yet been examined. Aiming to develop a safe and non-invasive procedure to prevent vigilance failures in prolonged tasks, the present study examined the possibility to mitigate vigilance loss by stimulating the LC-NE system via taVNS. Following a pre-registered protocol (https://osf.io/tu2xy/), 50 participants completed three repeated-sessions in a randomized order in which either active taVNS at individualized intensity set by participant, active taVNS set at 0.5 mA for all participants, or sham taVNS, was delivered while performing an attentional and vigilance task (i.e., ANTI-Vea). Changes in salivary alpha-amylase and cortisol concentrations were measured as markers of LC-NE activity. Self-reports of feelings associated with stimulation and guessing rate of active/sham conditions supported the efficacy of the single-blind procedure. Contrary to our predictions, the observed vigilance decrement was not modulated by active taVNS. Pairwise comparisons showed a mitigation by active taVNS on cortisol reduction across time. Interestingly, Spearman’s correlational analyses showed some inter-individual effects of taVNS on indirect markers of LC-NE, evidenced by positive associations between changes in salivary alpha-amylase and cortisol in active but not sham taVNS. We highlight the relevance of replicating and extending the present outcomes, investigating further parameters of stimulation and its effects on other indirect markers of LC-NE activity.

Skin conductance is a commonly used physiological measure during psychology experiments, such as during fear conditioning. Methods for scoring skin conductance responses are highly heterogeneous, though most researchers agree that manually inspected scores provide the highest quality data when compared to most available fully automated scoring methods. However, manual scoring is extremely time-consuming. We developed a semi-automated scoring program that significantly reduces the time required to process skin conductance response data at a level of quality akin to manual scoring. In contrast to all previous scoring programs, our program enables scoring of first, second, and third interval skin conductance responses. Using interclass correlation coefficients, Bland-Altman plots and Pareto analysis, we show here that our method is highly reliable and produces data that are almost identical to data that are manually scored. This software is very easy to use and is freely available to download and modify. We expect that this software will be helpful in reducing the time required to produce high quality first, second, and third interval skin conductance data for psychology researchers around the world.

High frequency heart rate variability (HRV) is a vagally-mediated physiological index reflecting parasympathetic activity that has been linked to emotion regulation capacity. However, very limited research has examined associations of physiological indices of regulation such as HRV with emotional functioning in daily life. The few studies that exist have small samples sizes and typically focus on only a narrow aspect of emotion regulation or emotional functioning. In this study, we examined associations between HRV 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 HRV would be associated with higher positive affect, lower negative affect, less affective variability, greater wellbeing, fewer depressive and idiographic [person-specific] symptoms, greater use of engagement emotion regulation strategies, and less use of avoidance emotion regulation strategies, as assessed in daily life. Results revealed that higher resting HRV in the laboratory was significantly associated with lower negative affect and less frequent use of avoidance emotion regulation strategies in daily life, although only avoidance strategies remained significant when both were included in the same model. We also observed a trend association, such that idiographic symptoms in daily life were associated with lower resting HRV. Theoretical and clinical implications are discussed, including the association of HRV with negatively-valenced, rather than positively-valenced, daily life experiences.

With the discovery of event-related potentials elicited by errors more than thirty years ago, a new avenue of research on performance monitoring, cognitive control, and decision making was opened. Since then, the field has developed and expanded fulminantly. After a brief overview on the EEG correlates of performance monitoring, this article reviews recent advancements in the field of performance monitoring based on single-trial analyses using independent component analysis, multiple regression, and multivariate pattern classification. Given the close interconnection between performance monitoring and reinforcement learning, computational modeling and model-based EEG analyses have made a particularly strong impact. The reviewed findings demonstrate that error- and feedback-related EEG dynamics represent variables reflecting how performance monitoring signals are weighted and transformed into an adaptation signal that guides future decisions and actions. The model-based single-trial analysis approach goes far beyond conventional peak-and-trough analyses of event-related potentials and enables testing mechanistic theories of performance monitoring, cognitive control and decision making.

Research suggests a potential of gamma oscillation entrainment for enhancing memory in Alzheimer’s disease and healthy subjects. Gamma entrainment can be accomplished with oscillatory electrical, but also sensory stimulation. However, comparative studies between sensory stimulation and transcranial alternating current stimulation (tACS) effects on memory processes are lacking. This study examined the effects of rhythmic gamma auditory stimulation (rAS) and temporal gamma-tACS on verbal long-term memory (LTM) and working memory (WM) in 74 healthy individuals. Participants were assigned to two groups according to the stimulation techniques (rAS or tACS). Memory was assessed in three experimental blocks, in which each participant was administered with control, 40 Hz, and 60 Hz stimulation in counterbalanced order. All interventions were well-tolerated, and participants reported mostly comparable side effects between real stimulation (40 Hz and 60 Hz) and the control condition. LTM immediate and delayed recall remained unaffected by stimulations, while immediate recall intrusions decreased during 60 Hz stimulation. Notably, 40 Hz interventions improved WM compared to control stimulations. These results highlight the potential of 60 Hz and 40 Hz temporal cortex stimulation for reducing immediate LTM recall intrusions and improving WM performance, respectively, probably due to the entrainment of specific gamma oscillations in the auditory cortex. The results also shed light on the comparative effects of these neuromodulation tools on memory functions, and their potential applications for cognitive enhancement and in clinical trials.

Touch is important for many aspects of our daily activities. One of the most important tactile characteristics is its perceived intensity. However, quantifying the intensity of perceived tactile stimulation beyond subjective self-reports remains challenging. Here, we show that pupil responses can objectively index the intensity of tactile stimulation in the absence of overt participant responses. In Experiment 1 (n=32), we stimulated three reportedly differentially sensitive body locations (finger, forearm, calf) with a single tap of a tactor while tracking pupil responses. Tactile stimulation resulted in greater pupil dilation than a baseline without stimulation. Furthermore, pupils dilated more for the more sensitive location (finger) than for the less sensitive locations (forearm, calf). In Experiment 2 (n=20) we extended these findings by manipulating the intensity of the stimulation with three different intensities, here a short vibration, always at the little finger. Again, pupils dilated more when being stimulated at higher intensities as compared to lower intensities. In summary, pupils dilated more for more sensitive parts of the body at constant stimulation intensity and for more intense stimulation at constant location. Taken together, the results show that the intensity of perceived tactile stimulation can be objectively measured with pupil responses – and that such responses are a versatile marker for touch research. Our findings may pave the way for previously impossible objective tests of tactile sensitivity, for example in minimally conscious state patients.