On the utility of P3 latency as an index of mental chronometry

P3b correlates of inspection time

Both P3b and the inspection time (IT) are related with intelligence, yet the P3b correlates of IT are not well understood. This event-related potential study addressed this question by asking participants (N = 28) to perform an IT task. There were three IT conditions with different levels of discriminative stimulus duration, i.e., 33 ms, 67 ms, and 100 ms, and a control condition with no target presentation (0 ms condition). We also measured participants' processing speed with four Elementary Cognitive Tests (ECTs), including a Simple Reaction Time task (SRT), two Choice Reaction Time tasks (CRTs), and a Pattern Discrimination task (PD). Results revealed that an increase in P3b latency with longer duration of the discriminative stimulus. Moreover, the P3b latency was negatively correlated with the accuracy of the IT task in the 33 ms condition, but not evident in the 67 and 100 ms conditions. Furthermore, the P3b latency of the 33 ms condition was positively correlated with the RT of the SRT, but not related with the RTs of CRTs or PD. A significant main effect of duration on the amplitude of P1 was also found. We conclude that the present study provides the neurophysiological correlates of the IT task, and those who are able to accurately perceive and process very briefly presented stimuli have a higher speed of information process, reflected by the P3b latency, yet this relationship is more obvious in the most difficult condition. Combined, our results suggest that P3b is related with the closure of a perceptual epoch to form the neural representation of a stimulus, in support of the "context closure" hypothesis.

N2 Responses in Youths With Psychosis Risk Syndrome and Their Association With Clinical Outcomes: A Cohort Follow-Up Study Based on the Three-Stimulus Visual Oddball Paradigm

OBJECTIVE

Schizophrenia often occurs during youth, and psychosis risk syndrome occurs before the onset of psychosis. The aim of this study was to determine whether the visual event-related potential responses in youths with psychosis risk syndrome were defective in the presence of interference stimuli and associated with their clinical outcomes.

METHODS

A total of 223 participants, including 122 patients with psychosis risk syndrome, 50 patients with emotional disorders, and 51 healthy control subjects, were assessed. Baseline EEG was recorded during the three-stimulus visual oddball task. The event-related potentials induced by square pictures with different colors were measured. Almost all patients with psychosis risk syndrome were followed up for 12 months and were reclassified into three subgroups: conversion, symptomatic, and remission. The differences in baseline event-related potential responses were compared among the clinical outcome subgroups.

RESULTS

The average N2 amplitude of the psychosis risk syndrome group was significantly less negative than that in the healthy control group (d=0.53). The baseline average N2 amplitude in the conversion subgroup was significantly less negative than that in the symptomatic (d=0.58) and remission (d=0.50) subgroups and in the healthy control group (d=0.97). The average N2 amplitude did not differ significantly between the symptomatic and remission subgroups (d=0.02). However, it was significantly less negative in the symptomatic and remission subgroups than in the healthy control group (d=0.46 and d=0.38). No statistically significant results were found in the P3 response.

CONCLUSIONS

Youths with psychosis risk syndrome had significant N2 amplitude defects in attention processing with interference stimuli. N2 amplitude shows potential as a prognostic biomarker of clinical outcome in the psychosis risk syndrome.

Behavioral and electrophysiological evidence of different processes during a target identification task assessing perceptual learning

This study aimed to test whether a target identification task involving same and different judgments to assess the ability to differentiate between similar pre-exposed stimuli-i.e., perceptual learning-could actually be assessing two different cognitive processes. Specifically, the hypothesis was that while "different" trials might be truly assessing the ability to differentiate between the pre-exposed stimuli, "same" trials might be assessing the ability to recognize one of these stimuli as the target. To test this hypothesis, accuracy on judgments as well as reaction times and event-related potentials for same/different trials were recorded after concurrent pre-exposure to similar stimuli. If same/different trials were assessing cognitive processes with different time courses, distinct outcomes for such trials would be expected at the behavioral and neural level. Results showed that participants were very accurate both in same and different judgments, indicating that they were perfectly able to differentiate between the stimuli after their concurrent presentations. However, larger P3 latencies and slower reaction times for different trials than for same trials were found. These results seem to support the idea that cognitive processes activated in same and different trials are different due to their distinct time courses. The importance of these findings for the theoretical approaches to perceptual learning is discussed.

The specificity of the auditory P300 responses and its association with clinical outcomes in youth with psychosis risk syndrome

Background

Schizophrenia often occurs in youth, and psychosis risk syndrome (PRS) occurs before the onset of psychosis. Assessing the neuropsychological abnormalities of PRS individuals can help in early identification and active intervention of mental illness. Auditory P300 amplitude defect is an important manifestation of attention processing abnormality in PRS, but it is still unclear whether there are abnormalities in the attention processing of rhythmic compound tone stimuli in PRS individuals, and whether the P300 amplitude induced by these stimuli is specific to PRS individuals and related to their clinical outcomes.

Methods

In total, 226 participants, including 122 patients with PRS, 51 patients with emotional disorders (ED), and 53 healthy controls (HC) were assessed. Baseline electroencephalography was recorded during the compound tone oddball task. The event-related potentials (ERPs) induced by rhythmic compound tone stimuli of two frequencies (20-Hz, 40-Hz) were measured. Almost all patients with PRS were followed up for 12 months and reclassified into four groups: PRS-conversion, PRS-symptomatic, PRS-emotional disorder, and PRS-complete remission. The differences in baseline ERPs were compared among the clinical outcome groups.

Results

Regardless of the stimulation frequency, the average P300 amplitude were significantly higher in patients with PRS than in those with ED (p = 0.003, d = 0.48) and in HC (p = 0.002, d = 0.44) group. The average P300 amplitude of PRS-conversion group was significantly higher than that of the PRS-complete remission (p = 0.016, d = 0.72) and HC group (p = 0.001, d = 0.76), and the average P300 amplitude of PRS-symptomatic group was significantly higher than that of the HC group (p = 0.006, d = 0.48). Regardless of the groups (PRS, ED, HC) or the PRS clinical outcome groups, the average P300 amplitude induced by 20-Hz tone stimulation was significantly higher than that induced by 40-Hz stimulation (ps < 0.001, Ƞ2 = 0.074-0.082). The average reaction times of PRS was significantly faster than that of ED (p = 0.01, d = 0.38), and the average reaction times of the participants to 20-Hz target stimulation was significantly faster than that to 40-Hz target stimulation (p < 0.001, d = 0.21).

Conclusion

The auditory P300 amplitude induced by rhythmic compound tone stimuli is a specific electrophysiological manifestation of PRS, and the auditory P300 amplitude induced by compound tone stimuli shows promise as a putative prognostic biomarker for PRS clinical outcomes, including conversion to psychosis and clinical complete remission.

Decrease in the P2 Amplitude of Object Working Memory after 8 h-Recovery Sleep Following 36 h-Total Sleep Deprivation: An ERP Study

The impact of sleep deprivation on working memory can only be reversed by recovery sleep (RS). However, there are limited electrophysiological studies on the effect of RS on the improvement in working memory after sleep deprivation, and the changes in the early components of event-related potentials (ERPs) before and after RS are still unclear. Therefore, this study aims to explore the effects of RS on the earlier ERP components related to object working memory following 36 h of total sleep deprivation (TSD). Twenty healthy male participants performed an object working memory task after 36 h of TSD and after 8 h of RS. Electroencephalogram data were recorded accordingly while the task was performed. Repeated ANOVA showed that P2 amplitudes related to object working memory decreased significantly after 8 h of RS compared to after a 36 h period of TSD, but there was no significant difference from baseline (BS), which indicates a trend of recovery to the baseline state. An 8 h RS can partially improve impaired object working memory caused by TSD. However, a longer period of RS is needed for the complete recovery of cognitive function after a long period of TSD.

When a look is enough: Neurophysiological correlates of referential speaker gaze in situated comprehension

Behavioral studies have shown that speaker gaze to objects in a co-present scene can influence listeners' expectations about how the utterance will unfold. These findings have recently been supported by ERP studies that linked the underlying mechanisms of the integration of speaker gaze with an utterance meaning representation to multiple ERP components. This leads to the question, however, as to whether speaker gaze should be considered part of the communicative signal itself, such that the referential information conveyed by gaze can help listeners not only form expectations but also to confirm referential expectations induced by the prior linguistic context. In the current study, we investigated this question by conducting an ERP experiment (N=24, Age:[19,31]), in which referential expectations were established by linguistic context together with several depicted objects in the scene. Those expectations then could be confirmed by subsequent speaker gaze that preceded the referential expression. Participants were presented with a centrally positioned face performing gaze actions aligned to utterances comparing two out of three displayed objects, with the task to judge whether the sentence was true given the provided scene. We manipulated the gaze cue to be either Present (toward the subsequently named object) or Absent preceding contextually Expected or Unexpected referring nouns. The results provided strong evidence for gaze as being treated as an integral part of the communicative signal: While in the absence of gaze, effects of phonological verification (PMN), word meaning retrieval (N400) and sentence meaning integration/evaluation (P600) were found on the unexpected noun, in the presence of gaze effects of retrieval (N400) and integration/evaluation (P300) were solely found in response to the pre-referent gaze cue when it was directed toward the unexpected referent with attenuated effects on the following referring noun.

MIND Dietary Pattern Adherence Is Selectively Associated with Cognitive Processing Speed in Middle-Aged Adults

BACKGROUND

Most previous work has focused on a single-nutrient, bottom-up approach when examining the influence of diet on neurocognition. Thus, the impact of dietary patterns on cognitive health is underinvestigated.

OBJECTIVES

We aimed to investigate the relation between different diet indices [i.e., Mediterranean, Dietary Approaches to Stop Hypertension (DASH), Healthy Eating Index-2015 (HEI-2015), and Mediterranean-DASH Intervention for Neurodegenerative Delay (MIND)] and attentional inhibition and neuroelectric function.

METHODS

We undertook a cross-sectional analysis of adults aged 34.1 ± 6.0 y (n = 207, 116 females) with a BMI of 18.5 to >40 kg/m2 who completed the Dietary History Questionnaire II (DHQII) FFQ (Past Month and Year with Serving Sizes) to assess adherence to different diet quality indices. Attentional inhibition was assessed using a modified Eriksen flanker task during which event-related potentials (ERPs) were recorded. The amplitude and latency of the P3/P300 ERP were used to index attentional resource allocation and information processing speed, respectively.

RESULTS

P3 peak latency was inversely associated with greater adherence to the MIND dietary pattern during incongruent flanker trials (∆R2 = 0.02, β = -0.14, P = 0.043) but not during congruent trials. Adherence to the Mediterranean, DASH, and HEI-2015 patterns was not associated with P3 latency (P > 0.05). No associations were observed between the diet indices and attentional inhibition at the behavioral level (i.e., accuracy or reaction time) or P3 amplitude (all P values >0.05).

CONCLUSIONS

Greater adherence to the MIND diet was selectively associated with faster information processing speed in middle-aged adults with healthy to obese BMI. Further, the influence of the MIND diet for faster information processing speed might be particularly beneficial when cognitive control demands are increased. Future intervention trials testing the effects of consuming a MIND diet on cognitive function are warranted to help inform dietary recommendations for healthy cognitive aging.

P3b Amplitude and Latency in Tic Disorders: A Meta-Analysis

P3b is an event-related potential (ERP) that may be abnormal in patients with tic disorders (TD), but evidence has been inconsistent. Given the possible association between P3b and TD and the need for biomarkers for TD, the primary objective of this meta-analysis was to characterize P3b in patients with TD in comparison to healthy controls (HCs).

METHODS

By searching PubMed, Embase, Web of Science, SCOPUS, Medline, and Google Scholar, we identified studies that compared P3b between TD patients and HCs. The amplitude and latency of P3b were then analyzed. Subgroup analyses were conducted to investigate the influence of different experimental factors on P3b indices.

RESULT

Overall, 19 articles involving 388 cases and 414 controls were evaluated. There were no significant abnormalities in P3b amplitude and latency in TD patients. The P3b amplitude of the TD patients was significantly decreased during the oddball task, and the P3b amplitude of the adult TD patients was also significantly decreased.

CONCLUSION

TD patients may have an abnormal P3b compared to HCs under specified conditions.

Exploring psychopathy traits on intertemporal decision-making, neurophysiological correlates, and emotions on time estimation in community adults

There are certain characteristics of psychopathy that may be related to changes in intertemporal choices. Specifically, traits such as impulsivity or lack of inhibitory control may be associated with a more pronounced discounting function in intertemporal choices (IC) and, in turn, this function may be based on changes in the basic mechanisms of time estimation (TE). Therefore, this study aimed to examine potential differences in neurophysiological correlates, specifically through N1, P3, and LPP measurements, which may be related to TE and IC, examining their modulation according to psychopathic traits, different emotional conditions, and different decision-making conditions. This experimental study included 67 adult participants (48 women) from the northern region of Portugal, who performed an intertemporal decision-making task and, of those, 19 participants (16 women), with a mean age of 25 years (SD = 5.41) and a mean of 16 years of schooling (SD = 3.37) performed the time estimation task. The instruments/measures applied were MoCA, used as a neurocognitive screening tool; the Triarchic Psychopathy Measure (TriPM), a self-report instrument with 58 items that map the core features of psychopathy along three facets – boldness, meanness, and disinhibition – and considers them continuously distributed among the general population; intertemporal decision-making and time estimation tasks – for the time estimation task, the stimuli consisted of 45 color images extracted from the Nencki Affective Picture System (NAPS). In the TE task, there was an almost significant effect of disinhibition on the values of θ, with higher values on this variable associated with greater values of θ in the unpleasant emotional condition. In the IC task, there were no significant effects of any psychopathy measure on the values of the gains and losses ratios. In addition, the analysis of the neurophysiological correlates of the IC task did not reveal a main effect of the decision-making condition, nor effects of any psychopathy measure on the N1 and P3 amplitudes. The analysis of the neurophysiological correlates of the TE task revealed that higher meanness values are associated with smaller N1 amplitude in the pleasant emotional condition, whereas higher disinhibition values are associated with greater N1 amplitude in the pleasant emotional condition. Still in this task, higher disinhibition values were associated with a smaller LPP amplitude in the unpleasant emotional condition. The increase in the distribution of attention resources towards time and/or the increase in activation states, including those originated by responses to emotional stimuli, may be the main factor that alters the way impulsive individuals and, presumably, individuals with high psychopathy, consider time when making decisions.

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There are certain characteristics of psychopathy that may be related to changes in IC.

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Higher meanness values are associated with smaller N1 amplitude in the pleasant emotional condition (TE task).

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Higher disinhibition values are associated with greater N1 amplitude in the pleasant emotional condition (TE task).

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Higher disinhibition values were associated with a smaller LPP amplitude in the unpleasant emotional condition (TE task).

Disentangling performance-monitoring signals encoded in feedback-related EEG dynamics

The feedback-related negativity (FRN) is a well-established electrophysiological correlate of feedback-processing. However, there is still an ongoing debate whether the FRN is driven by negative or positive reward prediction errors (RPE), valence of feedback, or mere surprise. Our study disentangles independent contributions of valence, surprise, and RPE on the feedback-related neuronal signal including the FRN and P3 components using the statistical power of a sample of N = 992 healthy individuals. The participants performed a modified time-estimation task, while EEG from 64 scalp electrodes was recorded. Our results show that valence coding is present during the FRN with larger amplitudes for negative feedback. The FRN is further modulated by surprise in a valence-dependent way being more positive-going for surprising positive outcomes. The P3 was strongly driven by both global and local surprise, with larger amplitudes for unexpected feedback and local deviants. Behavioral adaptations after feedback and FRN just show small associations. Results support the theory of the FRN as a representation of a signed RPE. Additionally, our data indicates that surprising positive feedback enhances the EEG response in the time window of the P3. These results corroborate previous findings linking the P3 to the evaluation of PEs in decision making and learning tasks.

The effects of daily step goals of 10,000, 12,500, and 15,000 steps per day on neural activity to food cues: A 24-week dose-response randomized trial

INTRODUCTION

The purpose of this study was to examine the effect of different levels of sustained physical activity on neural reflections of attention allocated toward food cues in first year college women.

METHODS

Seventy-nine first-year college women (18.6 ± 0.5 years) were recruited to participate in the study. Women were randomly assigned to a daily step goal of 10,000, 12,500, or 15,000 for 24 weeks. Once during weeks 16-24, participants were shown pictures of plated meals or flowers with the neural response measured using the P300 and late positive potential (LPP) components of the scalp-recorded event-related potential. Diet was assessed using the automated 24-h recall.

RESULTS

Both the P300 and LPP amplitudes were significantly more positive to food versus flower pictures (ps < .001). There was no interaction between step group and picture condition for the P300 and LPP. However, the 12,500-step group showed a significantly elevated LPP amplitude in comparison to the other groups for both food and flowers (F(2,74) = 8.84; p < .001). The effect size for the combined results (food and flowers) was 0.56 between 10,000 and 12,500-step groups, and 0.75 between the 12,500- and 15,000-step groups. In addition, the 12,500 group reduced caloric consumption over the course of the intervention (t(1,74) = 3.35, p = .001, d_z  = 0.59).

CONCLUSION

Habitual physical activity of 10,000, 12,500, or 15,000 steps per day does not preferentially alter neural reflections toward food cues compared to flowers. There may be a nonlinear response to pleasant visual cues, with 12,500 steps per day eliciting higher LPPs than either 10,000 or 15,000.

Functional Significance of Individual Differences in P3 Network Spatial Configuration

Abstract. The amplitude and latency of the P3 component in the electroencephalogram (EEG) event-related potentials (ERPs) are among the most extensively used markers for individual differences in normal and abnormal brain functions. In contrast, individual variations in spatial topography of the temporally-defined P3 component are relatively under-explored. Development in EEG-based source imaging opened up the possibility that individual-specific spatial configuration of the neural network underlying the temporally-defined P3 component bear a novel source of information for marking an individual difference in behavioral and cognitive function. In testing this hypothesis, a hybrid method consisting of blind source separation (BSS), equivalent current dipole (ECD) modeling, and hits-vector-based analysis was applied to continuous un-epoched EEG data collected from 13 healthy human participants performing a visual color oddball task. By analyzing the spatial configuration of the network underlying the temporally-defined P3 component, hereafter referred to as the P3N, we discovered that the contribution of each constituent structure within the P3N is not uniform. Instead, frontal lobe structures have significantly more involvement than other constituent structures, as quantitatively characterized by cross-individual reliability and a within-individual contribution to the P3N. A factor analysis of the hits vector data revealed that although P3 latency and amplitude did not show significant correlations with measures of the behavioral outcomes, scores of two factors derived from the hits vectors selectively predict behavioral reaction time and response correctness. These results support the hypothesis that variations in P3 spatial configuration reflect not merely noise but individual-specific features with functional significance.

Effect of types of stimuli, handedness and gender differences on reaction time among adults students during the COVID-19 pandemic

Study aim: The COVID-19 pandemic has unhinged the lives of people across the globe, in particular, university students who are home-schooling. No study has investigated the influence of specific parameters on reaction time (RT) among university students during the COVID-19 pandemic. The current study aims to describe the relationship between RT and parameters (types of stimuli, handedness, and gender differences) that may affect its values during the COVID-19 pandemic.

Material and methods: RT of 60 volunteers to visual and auditory stimuli were recorded using the drop ruler method. RT was compared within-subject with respect to handedness and type of stimulus, and between subjects with regards to gender.

Results: Although a small difference between RT reported as a function of hands and gender was observed, these results were statistically insignificant. However, females had a significant shorter RT to visual than the auditory stimulus.

Conclusions: Findings showed that no significant differences were obtained between all comparisons made, except between females RT to visual stimulus and auditory stimulus. This can be attributed to the high level of stress and anxiety that may occur among students due to the COVID-19, which is the most prevalent and dangerous topic for university students, especially female students.

Banknote authenticity is signalled by rapid neural responses

Authenticating valuable objects is widely assumed to involve protracted scrutiny for detection of reproduction flaws. Yet, accurate authentication of banknotes is possible within one second of viewing, suggesting that rapid neural processes may underpin counterfeit detection. To investigate, we measured event-related brain potentials (ERPs) in response to briefly viewed genuine or forensically recovered counterfeit banknotes presented in a visual oddball counterfeit detection task. Three ERP components, P1, P3, and extended P3, were assessed for each combination of banknote type (genuine, counterfeit) and overt response (“real”, “fake”). P1 amplitude was greater for oddballs, demonstrating that the initial feedforward sweep of visual processing yields the essential information for differentiating genuine from counterfeit. A similar oddball effect was found for P3. The magnitude of this P3 effect was positively correlated with behavioural counterfeit sensitivity, although the corresponding correlation for P1 was not. For the extended P3, amplitude was greatest for correctly detected counterfeits and similarly small for missed counterfeits, incorrectly and correctly categorised genuine banknotes. These results show that authentication of complex stimuli involves a cascade of neural processes that unfolds in under a second, beginning with a very rapid sensory analysis, followed by a later decision stage requiring higher level processing.

Neural correlates of abnormal cognitive conflict resolution in major depression: An event-related potential study

Abnormal cognitive conflict resolution has been considered as a critical element of executive dysfunctions inpatient with major depression (MD). Further clarifying whether there was a deficit at perceptual encoding stage or the early response-execution stage in conflict control function by event-related potential (ERP) technique in MD would be helpful in understanding the neural mechanism of MD. Participants included twenty-six depressed patients and twenty-six healthy controls (HCs). All participants measured with Hamilton Depression Scale (17-item edition, HAMD) and a Simon task. Electroencephalograms were synchronously recorded when performing the Simon task. The method of residue iteration decomposition was used to analyze the lateralized readiness potential (LRP) and P300 components, which contributed to divides ERP components into a stimulus-locked component (S-cluster), a response-locked component (R-cluster) and an intermediate component cluster (C-cluster) by using latency variability and time markers. Results showed that reactive times (RTs) for both groups were fastest in congruent trials, and slowest in incongruent trials; however, there is no difference in RTs under the three conditions between two groups. Accuracy Rate (ACC) for both groups were the highest in neutral trials, and the lowest in incongruent trials; ACC in MD group were all lower than that of HC group under three conditions. ERP data analyses showed that depressed patients had a deficit in activating the correct response, as reflected by reduced amplitudes of R-LRP, but no abnormality in LRP-S and P300-C. In conclusion, patients with MD present conflict control dysfunction (i.e., abnormal cognitive conflict resolution) at the early response-execution stage, not at perceptual encoding stage, which may be reflected by the reduced R-LRP amplitudes. The abnormal cognitive conflict resolution in activating the correct response might constitute an interesting treatment target.

A neural network predicting the amplitude of the N2pc in individual EEG datasets

Objective.The N2pc is a small amplitude transient interhemispheric voltage asymmetry used in cognitive neuroscience to investigate subject's allocation of selective visuo-spatial attention. N2pc is typically estimated by averaging the sweeps of the electroencephalographic (EEG) signal but, in absence of explicit normative indications, the number of sweeps is often based on arbitrariness or personal experience. With the final aim of reducing duration and cost of experimental protocols, here we developed a new approach to reliably predict N2pc amplitude from a minimal EEG dataset.Approach.First, features predictive of N2pc amplitude were identified in the time-frequency domain. Then, an artificial neural network (NN) was trained to predict N2pc mean amplitude at the individual level. By resorting to simulated data, accuracy of the NN was assessed by computing the mean squared error (MSE) and the amplitude discretization error (ADE) and compared to the standard time averaging (TA) technique. The NN was then tested against two real datasets consisting of 14 and 12 subjects, respectively.Main result.In simulated scenarios entailing different number of sweeps (between 10 and 100), the MSE obtained with the proposed method resulted, on average, 1/5 of that obtained with the TA technique. Implementation on real EEG datasets showed that N2pc amplitude could be reliably predicted with as few as 40 EEG sweeps per cell of the experimental design.Significance.The developed approach allows to reduce duration and cost of experiments involving the N2pc, for instance in studies investigating attention deficits in pathological subjects.

Perceptual and cognitive processes in augmented reality - comparison between binocular and monocular presentations

In the present study, we investigated the difference between monocular augmented reality (AR) and binocular AR in terms of perception and cognition by using a task that combines the flanker task with the oddball task. A right- or left-facing arrowhead was presented as a central stimulus at the central vision, and participants were instructed to press a key only when the direction in which the arrowhead faced was a target. In a small number of trials, arrowheads that were facing in the same or opposite direction (flanker stimuli) were presented beside the central stimulus binocularly or monocularly as an AR image. In the binocular condition, the flanker stimuli were presented to both eyes, and, in the monocular condition, only to the dominant eye. The results revealed that participants could respond faster in the binocular condition than in the monocular one; however, only when the flanker stimuli were in the opposite direction was the response faster in the monocular condition. Moreover, the results of event-related brain potentials (ERPs) showed that all stimuli were processed in both the monocular and the binocular conditions in the perceptual stage; however, the influence of the flanker stimuli was attenuated in the monocular condition in the cognitive stage. The influence of flanker stimuli might be more unstable in the monocular condition than in the binocular condition, but more precise examination should be conducted in a future study.

Rapid attentional adaptations due to language (monolingual vs bilingual) context

Does our general attentional system adapt to the language context we are in? Bilinguals switch between contexts in which only one language is present or both languages are equiprobable. Previous research by Wu and Thierry (2013) suggested that the bilingual language context can modify the workings of inhibitory control mechanisms. Here we investigate whether this can be replicated and whether other attentional mechanisms (alerting and orienting) also adjust depending on whether we are in a bilingual or a monolingual situation. Bilinguals performed the Attentional Network Task (ANT) task, which allows us to measure three types of attentional processes: alerting, orienting and executive control. Crucially, while performing the ANT task, participants also saw words presented in only one language (e.g., Catalan; monolingual context) or in two languages (Catalan and Spanish; bilingual context); this allowed us to assess whether the three attentional processes would be modified by language context. Compared to the monolingual context, in the bilingual context the target-P3 amplitude was enhanced for the alerting and executive control networks but not for the orienting network. This suggests that bilinguals' state of alertness was enhanced when surrounded by words from two languages. Exploratory analyses reveal that within the bilingual context, language switches have an alerting effect, as indexed by a greater target-N1, thus impacting upcoming visual processing of the flanker. Response hand activation is speeded up for congruent trials in a similar way that arbitrary alerting cues speed them up. This speed-up was reflected in a greater LRP in the bilingual context, but it was not reflected in behavioral measures (RTs or ACC). Thus, a bilingual context can enhance attentional capacity towards non-linguistic information. It also reveals how flexible the cognitive system is.

Tracking Cognitive Spare Capacity During Speech Perception With EEG/ERP: Effects of Cognitive Load and Sentence Predictability

OBJECTIVES

Listening to speech in adverse listening conditions is effortful. Objective assessment of cognitive spare capacity during listening can serve as an index of the effort needed to understand speech. Cognitive spare capacity is influenced both by signal-driven demands posed by listening conditions and top-down demands intrinsic to spoken language processing, such as memory use and semantic processing. Previous research indicates that electrophysiological responses, particularly alpha oscillatory power, may index listening effort. However, it is not known how these indices respond to memory and semantic processing demands during spoken language processing in adverse listening conditions. The aim of the present study was twofold: first, to assess the impact of memory demands on electrophysiological responses during recognition of degraded, spoken sentences, and second, to examine whether predictable sentence contexts increase or decrease cognitive spare capacity during listening.

DESIGN

Cognitive demand was varied in a memory load task in which young adult participants (n = 20) viewed either low-load (one digit) or high-load (seven digits) sequences of digits, then listened to noise-vocoded spoken sentences that were either predictable or unpredictable, and then reported the final word of the sentence and the digits. Alpha oscillations in the frequency domain and event-related potentials in the time domain of the electrophysiological data were analyzed, as was behavioral accuracy for both words and digits.

RESULTS

Measured during sentence processing, event-related desynchronization of alpha power was greater (more negative) under high load than low load and was also greater for unpredictable than predictable sentences. A complementary pattern was observed for the P300/late positive complex (LPC) to sentence-final words, such that P300/LPC amplitude was reduced under high load compared with low load and for unpredictable compared with predictable sentences. Both words and digits were identified more quickly and accurately on trials in which spoken sentences were predictable.

CONCLUSIONS

Results indicate that during a sentence-recognition task, both cognitive load and sentence predictability modulate electrophysiological indices of cognitive spare capacity, namely alpha oscillatory power and P300/LPC amplitude. Both electrophysiological and behavioral results indicate that a predictive sentence context reduces cognitive demands during listening. Findings contribute to a growing literature on objective measures of cognitive demand during listening and indicate predictable sentence context as a top-down factor that can support ease of listening.

Acute High Level Noise Exposure Can Cause Physiological Dysfunction in Macaque Monkeys: Insight on the Medical Protection for Special Working Environmental Personnel

The high level noise caused by intense acoustic weapons and blasting is a common source of acute acoustic trauma faced by some special environmental personnel. Studies have shown that high level noise can cause auditory and non-auditory effects. However, there are few reports on the biological effects, especially the non-auditory effects of acute high level noise exposure in simulated special working environments, and the great differences between experimental animals and human beings make it difficult to extrapolate from research conclusions. In this study, macaque monkeys were used to detect the effects of acute high level noise exposure on hearing, cognition, and cardiovascular function. Auditory brainstem response, auditory P300, and electrocardiogram (ECG) of macaque monkeys were measured. Results showed that acute high level noise exposure caused permanent hearing threshold shifts; partial hearing loss which couldn’t recover to normal levels in the detection period; pathological changes in T wave and QRS complexes; and large fluctuations in cognitive ability after exposure, which finally recovered to normal. These alterations may be a combination of effects caused by stress-induced neuroendocrine dysfunction and mechanical damage of auditory organs. To elaborate the exact mechanism, further studies are still needed. Meanwhile, positive measures should be taken to reduce the incidence of acute high level noise injury.

Ensemble Statistics Can Be Available before Individual Item Properties: Electroencephalography Evidence Using the Oddball Paradigm

Behavioral studies have shown that statistical properties of object groups are perceived accurately with brief exposure durations. This finding motivated the hypothesis that ensemble perception occurs rapidly in vision. However, the precise timing of ensemble perception remains unclear. Here, we used the superior temporal resolution of electroencephalography to directly compare the timing of ensemble processing to that of individual object processing. The P3b was chosen as a particular component of interest, as it is thought to measure the latency of stimulus evaluation. Participants performed a simple "oddball" task in which sets of 51 lines with varied orientations sequentially flashed briefly on the display. In these sequences, there was a 20% chance of an individual oddball, wherein one marked object tilted clockwise, and a 20% chance of an ensemble oddball, wherein the average orientation of the set tilted clockwise. In counterbalanced blocks, participants were instructed to respond to either individual or ensemble oddballs. ERP analysis was performed to test the timing of this processing. At parietal electrodes, P3b components were found for both individual and ensemble oddballs. Ensemble P3b components were found to occur significantly earlier than individual P3b components, as measured with both 50% area latency and 50% onset latency. Using multivariate pattern analysis, ensemble oddball trials were classifiable from standard trials significantly earlier in their timecourse than individual oddball trials. Altogether, these results provide compelling evidence that ensemble perception occurs rapidly and that ensemble properties can be available earlier than individual object properties.

Error Processing During the Online Retrieval of Probabilistic Sequence Knowledge

Abstract. Adaptive behavior involves rapid error processing and action evaluation. However, it has not been clarified how errors contribute to automatic behaviors that can be retrieved to successfully adapt to our complex environment. Automatic behaviors strongly rely on the process of probabilistic sequence learning and memory. Therefore, the present study investigated error processing during the online retrieval of probabilistic sequence knowledge. Twenty-four healthy young adults acquired and continuously retrieved a repeating stimulus sequence reflected by reaction time (RT) changes on a rapid forced-choice RT task. Performance was compared with a baseline that denoted the processing of random stimuli embedded in the probabilistic sequence. At the neurophysiological level, event-related brain potentials synchronized to responses were measured. Error processing was tracked by the error negativity (Ne) and the error positivity (Pe). The mean amplitude of the Ne gradually decreased as the task progressed, similarly for the sequence retrieval and the embedded baseline process. The mean amplitude of the Pe increased over time, likewise, irrespective of the type of the stimuli. Accordingly, we propose that automatic error detection (Ne) and conscious error evaluation (Pe) are not sensitive to sequence learning and retrieval. Overall, the present study provides insight into how error processing takes place for the retrieval of sequence knowledge in a probabilistic environment.

Change detection of auditory tonal patterns defined by absolute versus relative pitch information. A combined behavioural and EEG study

The human auditory system often relies on relative pitch information to extract and identify auditory objects; such as when the same melody is played in different keys. The current study investigated the mental chronometry underlying the active discrimination of unfamiliar melodic six-tone patterns by measuring behavioural performance and event-related potentials (ERPs). In a roving standard paradigm, such patterns were either repeated identically within a stimulus train, carrying absolute frequency information about the pattern, or shifted in pitch (transposed) between repetitions, so only relative pitch information was available to extract the pattern identity. Results showed that participants were able to use relative pitch to detect when a new melodic pattern occurred. Though in the absence of absolute pitch sensitivity significantly decreased and behavioural reaction time to pattern changes increased. Mismatch-Negativity (MMN), an ERP indicator of auditory deviance detection, was elicited at approximately 206 ms after stimulus onset at frontocentral electrodes, even when only relative pitch was available to inform pattern discrimination. A P3a was elicited in both conditions, comparable in amplitude and latency. Increased latencies but no differences in amplitudes of N2b, and P3b suggest that processing at higher levels is affected when, in the absence of absolute pitch cues, relative pitch has to be extracted to inform pattern discrimination. Interestingly, the response delay of approximately 70 ms on the behavioural level, already fully manifests at the level of N2b. This is in accordance with recent findings on implicit auditory learning processes and suggests that in the absence of absolute pitch cues a slowing of target selection rather than a slowing of the auditory pattern change detection process causes the deterioration in behavioural performance.

Sympathetic Nervous System and Exercise Affects Cognition in Youth (SNEACY): study protocol for a randomized crossover trial

BACKGROUND

There is an increasing prevalence of physical inactivity during childhood, which is associated with a variety of health problems. However, the mechanisms by which acute exercise benefits cognition in childhood remains unknown. Here we describe the protocol for a randomized crossover trial called SNEACY (Sympathetic Nervous System & Exercise Affects Cognition in Youth), a study designed to better understand mechanisms linking acute exercise and cognition in 9-10-year-old healthy, cognitively normal children.

METHODS

Children from the Greater Boston, MA region will be recruited to participate in this single center study. A randomized crossover design will be utilized, such that participants will act as their own controls, through initial randomization to condition assignment and condition counterbalancing across participants. One hundred three children will participate in three randomized acute interventions: moderate intensity treadmill exercise (20 min, 70-75% of their maximal heart rate), seated rest (20 min), and a Trier Social Stress Test for Children (14 min). These visits will occur on 3 three separate days, approximately 5-8 days apart. Before and after each intervention, children complete a variety of cognitive tasks measuring attentional inhibition while their neuroelectric activity is recorded. Variables of interest include EEG data, accuracy and reaction time, academic achievement, and salivary alpha amylase. Academic achievement is also assessed following interventions. In addition, children provide passive drool samples throughout the interventions to measure various biomarkers that may explain the acute exercise benefit on cognition.

DISCUSSION

The results from this study could influence educational and public health recommendations to enhance cognition and learning in pre-adolescent children.

TRIAL REGISTRATION

ClinicalTrials.gov NCT03592238 . Registered on 19 July 2018.

The self-esteem implicit association test is valid: Evidence from brain activity

A distinct challenge of implicit self-esteem research is the dubious validity of measures for implicit self-esteem. We conducted two event-related potential (ERP) studies to examine whether implicit self-esteem measured by the Implicit Association Test (IAT) actually reflects the automatic self-evaluation. We adopted the regular IAT and the Go/No-go Association Task (GNAT), respectively, to measure implicit self-esteem in two studies. We focused on the P300 that reflects the stimulus evaluation process. Study 1 revealed that participants responded faster to self pairing with good than to self pairing with bad whereas self pairing with bad elicited a delayed P300 compared with self pairing with good. Study 2 replicated these findings and further highlighted that the index of implicit self-esteem based on reaction time is correlated with that based on P300 latency. Our results suggest that implicit self-esteem assessed by the IAT measures automatic self-evaluation, thus providing neural evidence for the validity of implicit self-esteem.

Attentional Bias Deficits in Adolescent Suicide Attempters During an Emotional Stroop Task: An ERP Study

There is increasing evidence that, in adolescence, attentional bias plays a critical role in the vulnerability for suicidal behaviour. No studies to date have investigated the neurophysiological correlates of attentional bias in adolescent suicidality. The present study uses event-related potentials (ERPs) to investigate such processing in inpatient adolescents admitted for an acute suicide crisis using an Emotional Stroop Task (EST). In this task, participants are asked to name the colour of words varying in emotional valence (positive, negative, neutral, suicide-related). Suicidal individuals are hypothesised to be more preoccupied by the context of the suicide-related stimuli, which may interfere with their ability to perform the colour naming task. Seventeen adolescents with acute suicidal behaviour and 17 age- and gender-matched healthy controls performed an EST while ERPs were recorded. Suicide attempters showed increased reaction times to suicide-related words compared to other emotion categories, while the controls did not. The amplitude of the early posterior negativity (EPN) was not significantly different across groups or emotional valence. A double peak P3 (early-P3 and late-P3) was observed in both groups. Both the early- and late-P3 were significantly reduced in amplitude in the suicide attempter group compared to the control group, regardless of emotional valence. The late-P3 latency was also significantly delayed in the suicide attempters compared to controls. The behavioural findings support the attentional bias theories of suicide attempters and extend these findings to adolescents. Furthermore, large early- and late-P3 provide evidence that cognitive strategies employed by two groups did markedly differ.

The effects of poverty stereotype threat on inhibition ability in individuals from different income-level families

INTRODUCTION

Poverty is characterized by a scarcity of resources and a threat of certain stereotypes. However, the effects of stereotype threat are largely dependent on various factors, both negative and positive. Few psychophysiological studies have studied the effects of poverty stereotype threats on inhibition ability in wealth and impoverished individuals.

METHODS

To fill this gap in the literature, this study used the event-related potential (ERP) technique to explore the brain mechanisms associated with stereotype threat in 135 participants.

RESULTS

Behavioral results showed that the rich group (participants from higher-income families) had better inhibition ability than the impoverished group (participants from lower-income families), with significantly shorter reaction time and significantly greater accuracy for poverty-related stimuli when in the nonthreat condition. Additionally, poverty stereotype threat could improve performance of the impoverished group for poverty-related stimuli. The electrophysiological results showed significantly larger P3 mean amplitude and significantly longer P3 latency in the rich group than the impoverished group in the nonthreat condition. Although no significant between-group differences were found in the threat condition, the results show that the effect of poverty stereotype threat varies with different income-level persons, for both behavioral and P3 data.

CONCLUSION

These findings suggest that impoverished people have worse inhibition abilities. Further, poverty stereotype threat has different effects on people according to their income level and could help to explain irrational consumption behaviors in people.

Mechanisms of face specificity - Differentiating speed and accuracy in face cognition by event-related potentials of central processing

Given the crucial role of face recognition in social life, it is hardly surprising that cognitive processes specific for faces have been identified. In previous individual differences studies, the speed (measured in easy tasks) and accuracy (difficult tasks) of face cognition (FC, involving perception and recognition of faces) have been shown to form distinct abilities, going along with divergent factorial structures. This result has been replicated, but remained unexplained. To fill this gap, we first parameterized the sub-processes underlying speed vs. accuracy in easy and difficult memory tasks for faces and houses in a large sample. Then, we analyzed event-related potentials (ERPs) extracted from the EEG by using residue iteration decomposition (RIDE), yielding a central (C) component that is comparable to a purified P300. Structural equation modeling (SEM) was applied to estimate face specificity of C component latencies and amplitudes. If performance in easy tasks relies on purely general processes that are insensitive to stimulus content, there should be no specificity of individual differences in the latency recorded in easy tasks. However, in difficult tasks specificity was expected. Results indicated that, contrary to our predictions, specificity occurred in the C component latency of both speed-based and accuracy-based measures, but was stronger in accuracy. Further analyses suggested specific relationships between the face-related C latency and FC ability. Finally, we detected specificity in RTs of easy tasks when single tasks were modeled, but not when multiple tasks were jointly modeled. This suggests that the mechanisms leading to face specificity in performance speed are distinct across tasks.

Fast fronto-parietal cortical dynamics of conflict detection and context updating in a flanker task

Recent research has found that the traditional target P3 consists of a family of P3-like positivities that can be functionally and topographically dissociated from one another. The current study examined target N2 and P3-like subcomponents indexing conflict detection and context updating at low- and high-order levels in the neural hierarchy during cognitive control. Electroencephalographic signals were recorded from 45 young adults while they completed a hybrid go/nogo flanker task, and Residue Iteration Decomposition (RIDE) was applied to functionally dissociate these peaks. Analyses showed a stimulus-locked frontal N2 revealing early detection and fast perceptual categorization of nogo, congruent and incongruent trials, resulting in frontal P3-like activity elicited by nogo trials in the latency-variable RIDE cluster, and by incongruent trials in the response-locked cluster. The congruent trials did not elicit frontal P3-like activity. These findings suggest that behavioral incongruency effects are related to intermediate and later stages of motor response re-programming.

Asymmetric effects of graspable distractor disks on motor preparation of successive grasps: A behavioural and event-related potential (ERP) study

There is evidence that seeing a graspable object automatically elicits a preparatory motor process. However, it is unclear whether this implicit visuomotor process might influence the preparation of a successive grasp for a different object. We addressed the issue by implementing a combined behavioural and electrophysiological paradigm. Participants performed pantomimed grasps directed to small or large disks with either a two (pincer) or a five-finger (pentapod) grip, after the presentation of congruent (same size) or incongruent (different size) distractor disks. Preview reaction times (PRTs) and response-locked lateralized readiness potentials (R-LRPs) were recorded as online indices of motor preparation. Results revealed asymmetric effects of the distractors on PRTs and R-LRPs. For pincer grip disks, incongruent distractors were associated with longer PRTs and a delayed R-LRP peak. For pentapod grip disks, conversely, incongruent distractors were associated with shorter PRTs and a delayed R-LRP onset. Supporting an interpretation of these effects as tapping into motor preparation, we did not observe modulations of stimulus-locked LRP's (sensitive to sensory processing), or of the P300 component (related to reallocating attentional resources). These results challenge models (i.e., the "dorsal amnesia" hypothesis) which assume that visuomotor information presented before a grasp will not affect how we later perform that grasp.

Operate P300 speller when performing other task

OBJECTIVE

The P300 speller is a classic brain-computer interface (BCI) paradigm that has the potential to restore impaired motor control function. However, previous studies have confirmed that the letter recognition accuracy (LRA) of the P300 speller is a challenge when performing other tasks.

APPROACH

To address this, we implemented a dynamic stopping strategy (DSS) to maintain the P300 speller LRA when performing multiple tasks simultaneously. Multiple tasks with dynamic workload levels were adopted to simulate the brain's other thinking activities while operating P300 speller. A Bayes-based DSS offline model was built in single-task (only P300 speller task) and an online P300 speller system was established to test the DSS algorithm feasibility in dual-task.

MAIN RESULTS

Online experimental results showed that the P300 speller with DSS could achieve a high LRA (96.9%) under dual-task, which was similar to single-task (98.7%, p = 0.126). Under dual-task, DSS dynamically adjusted the discriminant confidence according to the workload levels of the distraction tasks (correlation coefficient r = -0.68). Therefore, DSS can increase the repeated sequences to compensate for the reduction of P300 speller signal-to-noise ratio caused by parallel thinking activities. The average of repeated sequences increased significantly from 4.98 times under single-task to 6.22 times under dual-task (p < 0.005). These results indicated that the P300 speller feature is robust and the DSS model built in single-task maintained the applicability in various dual-tasks.

SIGNIFICANCE

Overall, this study provides a basis for the implementation of laboratory-developed BCI in real-world environments.

The neurocognitive underpinnings of the Simon effect: An integrative review of current research

For as long as half a century the Simon task - in which participants respond to a nonspatial stimulus feature while ignoring its position - has represented a very popular tool to study a variety of cognitive functions, such as attention, cognitive control, and response preparation processes. In particular, the task generates two theoretically interesting effects: the Simon effect proper and the sequential modulations of this effect. In the present study, we review the main theoretical explanations of both kinds of effects and the available neuroscientific studies that investigated the neural underpinnings of the cognitive processes underlying the Simon effect proper and its sequential modulation using electroencephalogram (EEG) and event-related brain potentials (ERP), transcranial magnetic stimulation (TMS), and functional magnetic resonance imaging (fMRI). Then, we relate the neurophysiological findings to the main theoretical accounts and evaluate their validity and empirical plausibility, including general implications related to processing interference and cognitive control. Overall, neurophysiological research supports claims that stimulus location triggers the creation of a spatial code, which activates a spatially compatible response that, in incompatible conditions, interferes with the response based on the task instructions. Integration of stimulus-response features plays a major role in the occurrence of the Simon effect (which is manifested in the selection of the response) and its modulation by sequential congruency effects. Additional neural mechanisms are involved in supporting the correct and inhibiting the incorrect response.

Dissociable Effects of Reward on P300 and EEG Spectra Under Conditions of High vs. Low Vigilance During a Selective Visual Attention Task

The influence of motivation on selective visual attention in states of high vs. low vigilance is poorly understood. To explore the possible differences in the influence of motivation on behavioral performance and neural activity in high and low vigilance levels, we conducted a prolonged 2 h 20 min flanker task and provided monetary rewards during the 20- to 40- and 100- to 120-min intervals of task performance. Both the behavioral and electrophysiological measures were modulated by prolonged task engagement. Moreover, the effect of reward was different in high vs. low vigilance states. The monetary reward increased accuracy and decreased the reaction time (RT) and number of omitted responses in the low but not in the high vigilance state. The fatigue-related decrease in P300 amplitude recovered to its level in the high vigilance state by manipulating motivation, whereas the fatigue-related increase in P300 latency was not modulated by reward. Additionally, the fatigue-related increase in event-related spectral power at 1-4 Hz was sensitive to vigilance decrement and reward. However, the spectral power at 4-8 Hz was only affected by the decrease in vigilance. These electrophysiological measures were not influenced by motivation in the state of high vigilance. Our results suggest that neural processing capacity, but not the timing of processing, is sensitive to motivation. These findings also imply that the fatigue-related impairments in behavioral performance and neural activity underlying selective visual attention only partly recover after manipulating motivation. Furthermore, our results provide evidence for the dissociable neural mechanisms underlying the fatigue-related decrease vs. reward-related increase in attentional resources.

The Disentangled Sub-Processes Involved in Implied Motion Contributing to Food Freshness: The Neural Evidence from ERPs

Implied motion can enhance the consumer’s judgment of food freshness. However, this enhancing effect has only been investigated for a few products. Furthermore, researchers have not conclusively determined whether the effects of the low-level visual sensory processing and high-level conceptual processing on food evaluation differ. In Experiment 1, using different fruits in static water (fruit_IS), fruit with implied moving water (fruit_IM), or only fruits as stimuli, we initially generalized the effect of implied motion on the broader category of fruit, and implied motion improved the perceived freshness of the fruit. In Experiment 2, we recorded event-related potentials (ERPs) and measured the temporal processes involved in the mechanism by which implied motion improved perceived fruit freshness. The behavioral results further supported the findings from Experiment 1. The ERP data revealed a pronounced positive difference between fruit_IM and fruit-only conditions recorded from posterior electrodes at approximately 200-300 ms (P2). This difference reflected the low-level visual implied motion sensory processing involved in the effect of implied motion on improving food freshness. Additionally, an early frontocentral negativity difference of approximately 300-500 ms between fruit_IM and fruit-only conditions was recorded, which reflected the high-level visual conceptual processing involved in the effect of implied motion on improving food freshness. These results strengthen and extend previous behavioral findings indicating that implied motion enhances the consumer’s judgment of food freshness across various food categories, and improves our understanding of the cognitive processes involved in the mechanism by which implied motion influences food judgments.

Chemosensory communication of aggression: women's fine-tuned neural processing of male aggression signals

The current study is the first to examine the central nervous processing of aggression chemosignals within men and women by means of chemosensory event-related potential (CSERP) analysis. Axillary sweat was collected from 17 men and 17 women participating in a competitive computer game (aggression condition) and playing a construction game (control condition). Sweat samples were pooled with reference to donor gender and condition, and presented to 23 men and 25 women via a constant flow olfactometer. Ongoing electroencephalogram was recorded from 61 scalp locations, CSERPs (P2, P3-1, P3-2) were analysed and neuronal sources calculated (low-resolution electromagnetic tomography, LORETA). Women, especially, showed larger P3-1 and P3-2 amplitudes in response to male as compared with female aggression signals (all p values < 0.01). The peak activation of this effect was related to activity within the dorsomedial prefrontal cortex (Brodmann area 8). As male aggression commonly targets physical harm, the competence of the human brain to sensitively detect male aggression signals is considered to be highly adaptive. The detection of male aggression signals seems to be of higher importance for women than for men. It is suggested that the processing of male aggression signals in women induces an immediate response selection. This article is part of the Theo Murphy meeting issue 'Olfactory communication in humans'.

Encoding, storage, and response preparation-Distinct EEG correlates of stimulus and action representations in working memory

Working memory (WM) allows for the active storage of stimulus- and higher level representations, such as action plans. This electroencephalography (EEG) study investigated the specific electrophysiological correlates dissociating action-related from stimulus-related representations in WM using three different experimental conditions based on the same stimulus material. In the experiment, a random sequence of single numbers (from 1 to 6) was presented and participants had to indicate whether the current number (N0 condition), the preceding number (N-1 condition), or the sum of the current and the preceding number (S-1 condition) was odd or even. Accordingly, participants had to store a stimulus representation in S-1 and an action representation in N-1 until the onset of the next stimulus. In the EEG, the storage of stimulus representations (S-1) was reflected by a fronto-central slow wave indicating the rehearsal of information that was required for the response in the following trial. In contrast, the storage of action representations (N-1) went along with a posterior positive slow wave, suggesting that the action plan was actively stored in WM until the presentation of the next stimulus. Crucially, preparing for the next response in N-1 was associated with increased contralateral mu/beta suppression, predicting the response time in the given trial. Our findings, thus, show that the WM processes for stimulus- and action representations can be clearly dissociated from each other with a distinct sequence of EEG correlates for encoding, storage, and response preparation.

Significance?& Significance! Empirical, methodological, and theoretical connections between the late positive potential and P300 as neural responses to stimulus significance: An integrative review

Event-related potential studies of emotional processing have focused on the late positive potential (LPP), a sustained positive deflection in the ERP that is increased for emotionally arousing stimuli. A prominent theory suggests that modulation of the LPP is a response to stimulus significance, defined in terms of the activation of appetitive and aversive motivational systems. The current review incorporates experimental studies showing that manipulations that alter the significance of stimuli alter LPP amplitude. Complementing these within-person studies, also included is individual differences research on depression wherein the LPP has been used to study reduced neural sensitivity to emotional stimuli. Finally, the current review builds an existing framework that the LPP observed in studies in emotional processing and the P300 observed in classic oddball studies may reflect a common response to stimulus significance. This integrative account has implications for the functional interpretation of these ERPs, their neurobiological mechanisms, and clinical applications.

Feature Overlap and Relevance Determine Sequential Modulations in the Simon Task

Abstract. Subjects usually respond faster and more accurate in trials in which the response location corresponds to a task-irrelevant stimulus location compared to when not. Previous research has shown, that this so-called Simon effect is reduced after non-corresponding compared to after corresponding trials. As of now it is yet unclear what exact mechanisms drive such sequential modulations. One theory assumes a conflict adaptation mechanism that decreases the influence of incongruent information after non-corresponding trials via increased cognitive control. However, other authors claim that feature integration processes may be the underlying mechanism as the amount of feature overlap differs between different correspondence sequences. Unfortunately, this also means that in the standard Simon task the repetition of task features and correspondence sequences are not independent. In order to address this issue, we mapped four stimuli to two responses in the present EEG study. This way, we created a task, which allows for sequences in which the stimulus identity may change without alternating the required response. These sequences may either comprise a change of the stimulus position or not and the contribution of feature integration as well as conflict adaptation processes could thus be observed independently. Our results indicate that the repetition of task features affects performance to a stronger degree than the correspondence sequence and feature integration processes do. Yet, an impact of both could still be observed. The strongest effect of feature repetitions on task performance was observed for task-relevant features, especially for the imperative stimulus identity itself. The EEG results support these findings. The amplitudes of the fronto-central N2 and the parietal P3 decreased with increasing feature overlap from one trial to the next. The posterior lateralization, reflected by the posterior contralateral negativity (PCN), however, appears to reflect mainly changes in the stimulus location and stimulus–response (S–R) correspondence rather than feature repetitions per se.

Neural Correlates of Attentional Processing of Threat in Youth with and without Anxiety Disorders

Late-stage attentional processing of threatening stimuli, quantified through event-related potentials (ERPs), differentiates youth with and without anxiety disorders. It is unknown whether early-stage attentional processing of threatening stimuli differentiates these groups. Examining both early and late stage attentional processes in youth may advance knowledge and enhance efforts to identify biomarkers for translational prevention and treatment research. Twenty-one youth with primary DSM-IV-TR anxiety disorders (10 males, ages 8-15 years) and 21 typically developing Controls (15 males, ages 8-16 years) completed a dot probe task while electroencephalography (EEG) was recorded, and ERPs were examined. Youth with anxiety disorders showed significantly larger (more positive) P1 amplitudes for threatening stimuli than for neutral stimuli, and Controls showed the opposite pattern. Youth with anxiety showed larger (more negative) N170 amplitudes compared with Controls. Controls showed significantly larger (more positive) P2 and P3 amplitudes, regardless of stimuli valence, compared with youth with anxiety disorders. ERPs observed during the dot probe task indicate youth with anxiety disorders display distinct neural processing during early stage attentional orienting and processing of faces; this was not the case for Controls. Such results suggest these ERP components may have potential as biomarkers of anxiety disorders in youth.

Olfactory Influences on Visual Categorization: Behavioral and ERP Evidence

Visual stimuli often dominate nonvisual stimuli during multisensory perception. Evidence suggests higher cognitive processes prioritize visual over nonvisual stimuli during divided attention. Visual stimuli should thus be disproportionally distracting when processing incongruent cross-sensory stimulus pairs. We tested this assumption by comparing visual processing with olfaction, a “primitive” sensory channel that detects potentially hazardous chemicals by alerting attention. Behavioral and event-related brain potentials (ERPs) were assessed in a bimodal object categorization task with congruent or incongruent odor–picture pairings and a delayed auditory target that indicated whether olfactory or visual cues should be categorized. For congruent pairings, accuracy was higher for visual compared to olfactory decisions. However, for incongruent pairings, reaction times (RTs) were faster for olfactory decisions. Behavioral results suggested that incongruent odors interfered more with visual decisions, thereby providing evidence for an “olfactory dominance” effect. Categorization of incongruent pairings engendered a late “slow wave” ERP effect. Importantly, this effect had a later amplitude peak and longer latency during visual decisions, likely reflecting additional categorization effort for visual stimuli in the presence of incongruent odors. In sum, contrary to what might be inferred from theories of “visual dominance,” incongruent odors may in fact uniquely attract mental processing resources during perceptual incongruence.

The response relevance of visual stimuli modulates the P3 component and the underlying sensorimotor network

The functional meaning and neural basis of the P3b component of ERPs are still under debate. One of the main issues is whether P3b reflects only stimulus-related processes (stimulus evaluation hypothesis) or response-related processes as well (stimulus-response or S-R link activation hypothesis). Here, we conducted an EEG experiment examining whether P3b may indeed reflect an S-R link activation, followed by an fMRI experiment in which we explored the brain areas and functional connectivity possibly constituting the neural basis of these sensorimotor links. In both experiments, two successive visual stimuli, S1 and S2, were presented with a 1 sec interval, and responses were defined either by S1 or S2, while participants responded only after S2 onset. The obtained EEG results suggest that P3b may be interpreted in terms of the S-R link activation account, although further studies are needed to disentangle P3-related activity from overlapping anticipatory activity. The obtained fMRI results showed that processing of the relevant S1 involved activation of a distributed postero-anterior sensorimotor network, and increased strength of functional connectivity within this network. This network may underlie activation of the S-R links, thus possibly also the P3b component, forming a bridging step between sensory encoding and response execution.

Neuronal activation in the human centromedian-parafascicular complex predicts cortical responses to behaviorally significant auditory events

Studies with non-human primates have suggested an excitatory influence of the thalamus on the cerebral cortex, with the centromedian-parafascicular complex (CM-Pf) being particularly involved in processes of sensory event-driven attention and arousal. To define the involvement of the human CM-Pf in bottom-up and top-down auditory attention, we simultaneously recorded cortical EEG activity and intracranial local field potentials (LFPs) via electrodes implanted for deep brain stimulation for the treatment of neuropathic pain. The patients (N ​= ​6) performed an auditory three-class oddball paradigm with frequent standard stimuli and two types of infrequent deviant stimuli (target and distractor). We found a parietal P3b to targets and a central P3a to distractors at the scalp level. Subcortical recordings in the CM-Pf revealed enhanced activation to targets compared to standards. Interarea-correlation analyses showed that activation in the CM-Pf predicted the generation of longer latency P3b scalp potentials specifically in the target condition. Our results provide first direct human evidence for a functional temporal relationship between target-related activation in the CM-Pf and an enhanced cortical target response. These results corroborate the hypothetical model of a cortico-basal ganglia loop system that switches from top-down to bottom-up mode in response to salient, task-relevant external events that are not predictable.

When a second language hits a native language. What ERPs (do and do not) tell us about language retrieval difficulty in bilingual language production

The accumulating evidence suggests that prior usage of a second language (L2) leads to processing costs on the subsequent production of a native language (L1). However, it is unclear what mechanism underlies this effect. It has been proposed that the L1 cost reflects inhibition of L1 representation acting during L1 production; however, previous studies exploring this issue were inconclusive. It is also unsettled whether the mechanism operates on the whole-language level or is restricted to translation equivalents in the two languages. We report a study that allowed us to address both issues behaviorally with the use of ERPs while focusing on the consequences of using L2 on the production of L1. In our experiment, native speakers of Polish (L1) and learners of English (L2) named a set of pictures in L1 following a set of pictures in either L1 or L2. Half of the pictures were repeated from the preceding block and half were new; this enabled dissociation of the effects on the level of the whole language from those specific to individual lexical items. Our results are consistent with the notion that language after-effects operate at a whole-language level. Behaviorally, we observed a clear processing cost on the whole-language level and a small facilitation on the item-specific level. The whole-language effect was accompanied by an enhanced, fronto-centrally distributed negativity in the 250-350 ms time-window which we identified as the N300 (in contrast to previous research, which probably misidentified the effect as the N2), a component that presumably reflects retrieval difficulty of relevant language representations during picture naming. As such, unlike previous studies that reported N2 for naming pictures in L1 after L2 use, we propose that the reported ERPs (N300) indicate that prior usage of L2 hampers lexical access to names in L1. Based on the literature, the after-effects could be caused by L1 inhibition and/or L2 interference, but the ERPs so far have not been informative about the causal mechanism.

Interactive Improvements of Visual and Auditory Function for Enhancing Performance in Youth Soccer Players

We analyzed the effects of a regular training program on the health- and skill-related physical fitness (PF) of talented soccer players aged < 12 years; visual reaction time (VRT) and auditory reaction time (ART) were also assessed. In this single-group interventional study, 78 talented male youth soccer players (mean age, 9.54 years) were critically selected by the Korean Educational Development Institute and underwent a 22-week training program consisting of 16 weeks of PF and basic skill training (90 min/week) and 6 weeks of intensive training (3, 150-min sessions/week). We assessed the pre- and post-training body composition, cardiovascular endurance, muscle strength and endurance, and flexibility. We also measured power, agility, coordination and speed, passing ability, VRT, and ART. All variables improved after training. Post-training VRT correlated with ART, muscle mass, power, cardiovascular endurance, 10-m dribble time, 10-m ball touch count, and 10-m successful pass count. ART only correlated with muscle mass. ART and 10-m ball-touch count influenced VRT, and VRT influenced ART. In conclusion, the training program enhanced the PF and visual- and auditory-related reactions in talented youth soccer players. This study suggests the importance of the assessed relationships, indicating that a training program that improves these parameters enhances the players’ performance.