Event-related Potential Effects Research Articles

How variable are the classic ERP effects during sentence processing? A systematic resampling analysis of the N400 and P600 effects

Although event-related potential (ERP) research on language processing has capitalized on key, theoretically influential components such as the N400 and P600, their measurement properties—especially the variability in their temporal and spatial parameters—have rarely been examined. The current study examined the measurement properties of the N400 and P600 effects elicited by semantic and syntactic anomalies, respectively, during sentence processing. We used a bootstrap resampling procedure to randomly draw many thousands of resamples varying in sample size and stimulus count from a larger sample of 187 participants and 40 stimulus sentences of each type per condition. Our resampling investigation focused on three issues: (a) statistical power; (b) variability in the magnitudes of the effects; and (c) variability in the temporal and spatial profiles of the effects. At the level of grand averages, the N400 and P600 effects were both robust and substantial. However, across resamples, there was a high degree of variability in effect magnitudes, onset times, and scalp distributions, which may be greater than is currently appreciated in the literature, especially for the P600 effects. These results provide a useful basis for designing future studies using these two well-established ERP components. At the same time, the results also highlight challenges that need to be addressed in future research (e.g., how best to analyze the ERP data without engaging in such questionable research practices as p-hacking).

Single-trial neurodynamics reveal N400 and P600 coupling in language comprehension

AbstractTheories of the electrophysiology of language comprehension are mostly informed by event-related potential effects observed between condition averages. We here argue that a dissociation between competing effect-level explanations of event-related potentials can be achieved by turning to predictions and analyses at the single-trial level. Specifically, we examine the single-trial dynamics in event-related potential data that exhibited a biphasic N400–P600 effect pattern. A group of multi-stream models can explain biphasic effects by positing that each individual trial should induce either an N400 increase or a P600 increase, but not both. An alternative, single-stream account, Retrieval-Integration theory, explicitly predicts that N400 amplitude and P600 amplitude should be correlated at the single-trial level. In order to investigate the single-trial dynamics of the N400 and the P600, we apply a regression-based technique in which we quantify the extent to which N400 amplitudes are predictive of the electroencephalogram in the P600 time window. Our findings suggest that, indeed, N400 amplitudes and P600 amplitudes are inversely correlated within-trial and, hence, the N400 effect and the P600 effect in biphasic data are driven by the same trials. Critically, we demonstrate that this finding also extends to data which exhibited only monophasic effects between conditions. In sum, the observation that the N400 is inversely correlated with the P600 on a by-trial basis supports a single stream view, such as Retrieval-Integration theory, and is difficult to reconcile with the processing mechanisms proposed by multi-stream models.

Asymetric Event-Related Potential Priming Effects Between English Letters and American Sign Language Fingerspelling Fonts.

Letter recognition plays an important role in reading and follows different phases of processing, from early visual feature detection to the access of abstract letter representations. Deaf ASL-English bilinguals experience orthography in two forms: English letters and fingerspelling. However, the neurobiological nature of fingerspelling representations, and the relationship between the two orthographies, remains unexplored. We examined the temporal dynamics of single English letter and ASL fingerspelling font processing in an unmasked priming paradigm with centrally presented targets for 200 ms preceded by 100 ms primes. Event-related brain potentials were recorded while participants performed a probe detection task. Experiment 1 examined English letter-to-letter priming in deaf signers and hearing non-signers. We found that English letter recognition is similar for deaf and hearing readers, extending previous findings with hearing readers to unmasked presentations. Experiment 2 examined priming effects between English letters and ASL fingerspelling fonts in deaf signers only. We found that fingerspelling fonts primed both fingerspelling fonts and English letters, but English letters did not prime fingerspelling fonts, indicating a priming asymmetry between letters and fingerspelling fonts. We also found an N400-like priming effect when the primes were fingerspelling fonts which might reflect strategic access to the lexical names of letters. The studies suggest that deaf ASL-English bilinguals process English letters and ASL fingerspelling differently and that the two systems may have distinct neural representations. However, the fact that fingerspelling fonts can prime English letters suggests that the two orthographies may share abstract representations to some extent.

An ERP measure of non-conscious memory reveals dissociable implicit processes in human recognition using an open-source automated analytic pipeline.

Non-conscious processing of human memory has traditionally been difficult to objectively measure and thus understand. A prior study on a group of hippocampal amnesia (N = 3) patients and healthy controls (N = 6) used a novel procedure for capturing neural correlates of implicit memory using event-related potentials (ERPs): old and new items were equated for varying levels of memory awareness, with ERP differences observed from 400 to 800 ms in bilateral parietal regions that were hippocampal-dependent. The current investigation sought to address the limitations of that study by increasing the sample of healthy subjects (N = 54), applying new controls for construct validity, and developing an improved, open-source tool for automated analysis of the procedure used for equating levels of memory awareness. Results faithfully reproduced prior ERP findings of parietal effects that a series of systematic control analyses validated were not contributed to nor contaminated by explicit memory. Implicit memory effects extended from 600 to 1000 ms, localized to right parietal sites. These ERP effects were found to be behaviorally relevant and specific in predicting implicit memory response times, and were topographically dissociable from other traditional ERP measures of implicit memory (miss vs. correct rejections) that instead occurred in left parietal regions. Results suggest first that equating for reported awareness of memory strength is a valid, powerful new method for revealing neural correlates of non-conscious human memory, and second, behavioral correlations suggest that these implicit effects reflect a pure form of priming, whereas misses represent fluency leading to the subjective experience of familiarity.

Successful reproduction of a large EEG study across software packages

As an active field of research and with the development of state-of-the-art algorithms to analyze EEG datasets, the parametrization of Electroencephalography (EEG) analysis workflows has become increasingly flexible and complex, with a great variety of methodological options and tools to be selected at each step. This high analytical flexibility can be problematic as it can yield to variability in research outcomes. Therefore, growing attention has been recently paid to understand the potential impact of different methodological decisions on the reproducibility of results.In this paper, we aim to examine how sensitive the results of EEG analyses are to variations in preprocessing with different software tools. We reanalyzed the shared EEG data (N = 500) from (Williams et al., 2021) using three of the most commonly used open-source Matlab-based EEG software tools: EEGLAB, Brainstorm and FieldTrip. After reproducing the same original preprocessing workflow in each software, the resulting event-related potentials (ERPs) were qualitatively and quantitatively compared in order to examine the degree of consistency/discrepancy between software packages. Our findings show a good degree of convergence in terms of the general profile of ERP waveforms, peak latencies and effect size estimates related to specific signal features. However, considerable variability was also observed in the magnitude of the absolute voltage observed with each software package as reflected by the similarity values and observed statistical differences at particular channels and time instants. In conclusion, we believe that this study provides valuable clues to better understand the impact of the software tool on the analysis of EEG results.

Beyond the N400: Confirmed and Disconfirmed Lexical Predictions in Aging

One of the basic tenets of predictive theories of language processing is that of misprediction cost. Post-N400 positive event-related potential (ERP) components are suitable for studying misprediction cost, but are not adequately described, especially in older adults, who show attenuated N400 ERP effects. We report a secondary analysis of a previously collected EEG data set. Using a picture–word matching paradigm, in which the target word could sometimes be predicted by context and sometimes not, the relationship between aging and late ERP effects was examined. Positivity effects for prediction violations were larger and more extended in older compared with younger adults, independent of context. Younger adults showed frontal negativity effects, indicating frame-shifting processes. Our data suggest that aging does not entail specific declines in prediction. Rather, they indicate that older adults may experience more processing difficulties than younger adults when their expectations are disconfirmed and that multiple mechanisms may be employed during language processing.

Perceptual learning of random acoustic patterns: Impact of temporal regularity and attention.

Perceptual learning is a powerful mechanism to enhance perceptual abilities and to form robust memory representations of previously unfamiliar sounds. Memory formation through repeated exposure takes place even for random and complex acoustic patterns devoid of semantic content. The current study sought to scrutinise how perceptual learning of random acoustic patterns is shaped by two potential modulators: temporal regularity of pattern repetition and listeners' attention. To this end, we adapted an established implicit learning paradigm and presented short acoustic sequences that could contain embedded repetitions of a certain sound segment (i.e., pattern) or not. During each experimental block, one repeating pattern recurred across multiple trials, whereas the other patterns were presented in only one trial. During the presentation of sound sequences that contained either temporally regular or jittered within-trial pattern repetitions, participants' attention was directed either towards or away from the auditory stimulation. Overall, we found a memory-related modulation of the event-related potential (ERP) and an increase in inter-trial phase coherence for patterns that recurred across multiple trials (compared to non-recurring patterns), accompanied by a performance increase in a (within-trial) repetition detection task when listeners attended the sounds. Remarkably, we show a memory-related ERP effect even for the first pattern occurrence per sequence when participants attended the sounds, but not when they were engaged in a visual distractor task. These findings suggest that learning of unfamiliar sound patterns is robust against temporal irregularity and inattention, but attention facilitates access to established memory representations upon first occurrence within a sequence.

Auditory pseudoword rhyming effects in bilingual children reflect second language proficiency: An ERP study

This study investigated second language (L2-English) phonological processing in 31 Spanish-English bilingual, 6- to 8-year-old schoolchildren in an event-related potential (ERP) auditory pseudoword rhyming paradigm. In addition, associations between ERP effects and L2 proficiency as measured by standardized tests of receptive language and receptive vocabulary were explored. We found a classic posterior ERP rhyming effect that was more widely distributed in children with higher L2 proficiency in group analyses and was larger for children with better L2 proficiency in correlation analyses. In contrast, the amplitude of an early (75–125 ms) auditory positivity was larger in children with lower L2 proficiency. This pattern suggests differential use of early and late auditory/phonological processing resources in the pseudoword rhyme task associated with L2 proficiency, which is consistent with the predictions of the lexical restructuring model in a bilingual context.

Perinatal nicotine exposure relates to stimulus-locked event-related potentials in early adolescence during an emotional go/no-go task

Nicotine exposure is associated with negative consequences on the developing brain, both in utero and after birth. We investigated the relationship between perinatal nicotine exposure and electroencephalographic brain activity recorded during an emotional faces Go/No-Go task among adolescents. Seventy-one adolescents aged 12–15 years completed a Go/No-Go task using fearful and happy faces. Parents completed questionnaire measures of their child's temperament and self-regulation and retrospectively reported on nicotine exposure during the perinatal period. Perinatally exposed children (n = 20) showed increased and prolonged frontal event-related potential (ERP) differentiation in stimulus-locked analyses; that is, greater emotion and condition differentiation in comparison with their non-exposed peers (n = 51). However, non-exposed children showed greater late emotion differentiation recorded over posterior sites. Response-locked ERP differences were not found. ERP effects were not related to temperamental, self-regulatory, or parental education and income-related factors. This study is the first to demonstrate a relationship between perinatal nicotine exposure and ERPs in an emotional Go/No-Go task among adolescents. Findings suggest that while conflict detection remains intact for adolescents with perinatal nicotine exposure, their attentional allocation to behaviourally relevant stimuli may be magnified to beyond optimal levels, particularly when emotion is salient in information processing. Future studies can extend these findings by isolating prenatal nicotine exposure and comparing its effects to isolated postnatal exposure and clarifying the implications of the face and performance processing differences in adolescence.

Sex-Determined Alteration of Frontal Electroencephalographic (EEG) Activity in Social Presence

This study represents a follow-up event-related potential (ERP) analysis of a prior investigation. The previous results showed that participants had most negative-tending ERPs in the mid-frontal brain region during exposure to neutral emotion pictures (compared to negative and positive pictures) while being accompanied by a significant other person (social presence condition). The present analysis aimed at investigating potential sex differences related to this phenomenon. Female and male participants' brain activity data from the previous study were analyzed separately for one representative mid-frontal electrode location selected on the basis of having the highest significance level. As a result, only female participants showed significantly more negative-tending potentials in response to neutral pictures, compared to both other emotion categories (positive and negative) in the social presence condition. This was not found in male participants. The respective ERP effect was most dominant at 838 ms post stimulus onset, which is slightly later than the effect found in the prior study. However, this result is interpreted as evidence that the general effect from the prior study can be understood as a largely female phenomenon. In line with the prior study, the present results are interpreted as a predominantly female activation in the mid-frontal brain region in response to neutral picture stimuli while being accompanied by a significant other person (social presence condition). Although only speculative, this would align with previous studies demonstrating sex-related hormonal and structural differences in the anterior cingulate cortex (ACC). In general, ACC activation has been associated with an integrative weighting function in ambiguous social settings, which makes sense given the ambiguous nature of neutral pictures in combination with a social presence condition.

Neural correlates of retrieval practice on the learning and memory retention of L3 French vocabulary

ABSTRACT This study used event-related potential (ERP) and retrieval practice effect paradigm to investigate the neurocognitive mechanisms underlying the retrieval practice effect in a third language (L3) vocabulary learning. Thirty-five Chinese (First Language, L1)-English (Second Language, L2) bilinguals without prior knowledge of French (L3) studied 120 French (L3)–English (L2) word pairs and then practiced the word pairs through retrieval practice or repeated studying. On a final recognition test 30 minutes later, the participants were asked to perform old/new recognition judgments while recording electroencephalography (EEG) signals. Behavioural results found that retrieval practice led to a higher accuracy rate and faster response time in the final test than repeated studying. ERP results found that retrieval practice elicited less negative N400 waveforms than repeated studying at the frontal site and less negative N400 waveforms than new condition at the central-parietal sites. By contrast, retrieval practice only elicited more positive LPC waveforms than new condition at the parietal site. In sum, the present results provide first neural evidence that retrieval practice facilitates L3 (French) vocabulary learning. These findings suggest that retrieval practice might involve more semantic information processing in L3 vocabulary learning, which supports the elaborative retrieval hypothesis of the retrieval practice effect.

Neurophysiological signatures of approximate number system acuity in preschoolers

BackgroundA hallmark of the approximate number system (ANS) is ratio dependence. Previous work identified specific event-related potentials (ERPs) that are modulated by numerical ratio throughout the lifespan. In adults, ERP ratio dependence was correlated with the precision of the numerical judgments with individuals who make more precise judgments showing larger ratio-dependent ERP effects. The current study evaluated if this relationship generalizes to preschoolers. MethodERPs were recorded from 56 4.5 to 5.5-year-olds while they compared the numerosity of two sequentially presented dot arrays. Nonverbal numerical precision, often called ANS acuity, was assessed using a similar behavioral task. ResultsOnly children with high ANS acuity exhibited a P2p ratio-dependent effect onsetting ∼250 ms after the presentation of the comparison dot array. Furthermore, P2p amplitude positively correlated with ANS acuity across tasks. ConclusionResults demonstrate developmental continuity between preschool years and adulthood in the neural basis of the ANS.

Task Demands Differentially Affect Processing of Intrinsic and Extrinsic Object Features in Working Memory

Some argue that visual working memory operates on integrated object representations. Here, we contend that obligatory feature integration occurs with intrinsic but not extrinsic object features. Working memory for shapes and colors was assessed using a change-detection task with a central test probe, while recording event-related potentials (ERPs). Color was either an intrinsic surface feature of a shape or connected to the shape via a proximal but spatially disjunct extrinsic frame. There were two types of test: The direct test required memory for shape and color; the indirect test required only shape memory. Study-test changes of color were therefore either task-relevant or task-irrelevant. We assessed performance costs and event-related potential (ERP) effects arising from color changes. In the direct test, performance was poorer for extrinsic than intrinsic stimuli; task-relevant color changes elicited enhanced frontal negativity (N2, FN400) for both intrinsic and extrinsic stimuli. In the indirect test, performance costs and ERP effects associated with irrelevant color change were larger for intrinsic than extrinsic stimuli. This suggests intrinsic information is more readily integrated into the working-memory representation and evaluated against the test probe. Findings imply that feature integration is not obligatory under all conditions but influenced by stimulus-driven and task-related focus of attention.

Behavioral and ERP effects of encoded facial expressions on facial identity recognition depend on recognized facial expressions.

Behavioral and event-related potential (ERP) studies have shown that the expressions of a face displayed in the encoding phase (encoded facial expressions) influences identity recognition of this face in a later recognition phase. As facial expressions displayed in the recognition phase (recognized facial expressions) might also influence facial identity recognition, the current study investigated whether the effect of encoded facial expressions on facial identity recognition changed depending on recognized facial expressions. Therefore, participants were asked to learn facial identities displaying angry, happy or neutral expressions during the encoding phase. In the subsequent recognition phase, participants were presented with the learned identities and several novel identities and asked to judge whether the prompted identities had been learned. Each identity displayed angry, happy and neutral expressions. The results showed that d' scores were smaller for happy-recognized identities (i.e., learned identities displaying happy expressions during the recognition phase) in the angry-encoded (i.e., learned identities that had displayed angry expressions during the preceding encoding phase) condition than in the neutral-encoded condition and for neutral-recognized identities in the angry-encoded condition than in the happy-encoded condition. ERP results showed that angry-encoded identities elicited less negative responses in the P200 and early posterior negativity (EPN)/N250 components and less positive responses in the late positive potential (LPP) component than happy-encoded identities. For neutral-recognized identities, LPP responses were reduced in the angry-encoded condition compared with those in the neutral-encoded condition. These findings might contribute to understanding the influence of previous and current facial expressions on facial identity recognition.

Longitudinal Effects of Breast Cancer Treatment on Neural Correlates of Attention.

Cognitive dysfunction has been observed consistently in a subset of breast cancer survivors. Yet, the precise physiological and processing origins of dysfunction remain unknown. The current study examined the utility of methods and procedures based on cognitive neuroscience to study cognitive change associated with cancer and cancer treatment. We used electroencephalogram and behavioral measures in a longitudinal design to investigate pre- versus post-treatment effects on attention performance in breast cancer patients (n = 15) compared with healthy controls (n = 24), as participants completed the revised Attention Network Test, a cognitive measure of alerting, orienting, and inhibitory control of attention. We found no group differences in behavioral performance from pretest to posttest, but significant event-related potential effects of cancer treatment in processing cue validity: After treatment, patients revealed decreased N1 amplitude and increased P3 amplitude, suggesting a suppressed early (N1) response and an exaggerated late (P3) response to invalid cues. The results suggest that treatment-related attentional disruption begins in early sensory/perceptual processing and extends to compensatory top-down executive processes.

First Language Matters: Event-Related Potentials Show Crosslinguistic Influence on the Processing of Placement Verb Semantics.

Second language (L2) learners experience challenges when word meanings differ across L1 and L2, and often display crosslinguistic influence (CLI) in speech production. In contrast, studies of online comprehension show more mixed results. Therefore, this study explored how L2 learners process fine-grained L2 verb semantics in the domain of caused motion (placement) and specifically the impact of having similar vs. non-similar semantics in the L1 and L2. Specifically, we examined English (20) and German (21) L2 learners of Swedish and native Swedish speakers (16) and their online neurophysiological processing and offline appropriateness ratings of three Swedish placement verbs obligatory for placement supported from below: sätta “set,” ställa “stand,” and lägga “lay.” The learners’ L1s differed from Swedish in that their placement verbs either shared or did not share semantic characteristics with the target language. English has a general placement verb put, whereas German has specific verbs similar but not identical to Swedish, stellen “set/stand” and legen “lay.” Event-related potentials (ERPs) were recorded while participants watched still frames (images) of objects being placed on a table and listened to sentences describing the event with verbs that either matched the image or not. Participants also performed an offline appropriateness rating task. Both tasks suggested CLI. English learners’ appropriateness ratings of atypical verb use differed from those of both native Swedish speakers’ and German learners, with no difference in the latter pair. Similarly, German learners’ ERP effects were more similar to those of the native Swedish speakers (increased lateral negativity to atypical verb use) than to those of the English learners (increased positivity to atypical verb use). The results of this explorative study thus suggest CLI both offline and online with similarity between L1 and L2 indicating more similar processing and judgments, in line with previous production findings, but in contrast to previous ERP work on semantic L2 processing.

Respectfulness-processing revisited: An ERP study of Chinese sentence reading.

In Mandarin Chinese, an important manifestation of respectfulness is the use of different forms of second-person pronouns. Jiang et al. (2013) examined the event-related potential (ERP) correlates of processing respectful and plain pronouns in Chinese. However, this study suffered from a few methodological limitations, which restricted both the reliability and functional interpretations of the study's findings. In the present study, we resolved these limitations and further investigated the neurocognitive mechanisms of processing the respectfulness of pronouns. In the present study, participants read 160 critical Chinese sentences with a second-person pronoun (ni or nin) that was either consistent or inconsistent with its prior sentence context in terms of respectfulness, as well as 240 filler sentences. Unlike the previous study that reported a 300-500 ms negative response (N400) for both types of inconsistent pronouns, a sustained positive response for Nin inconsistent and a sustained negativity response for Ni inconsistent in the late time window, the present study found an N400 response and late sustained negativity for Nin inconsistent, but not for Ni inconsistent. Furthermore, the cluster-based permutation showed a significant negative cluster for Nin inconsistent, extending from 432-622 ms. We related this negative response for Nin inconsistent with recent accounts of the N400 and late negativity. Finally, the absence of the ERP effect for the Ni condition was linked to the role of the pragmatic property of Ni.

Variations in Pupil Size Related to Memory for Recently Presented Words and Event Related Potentials.

Pupillometry has been found to be correlated with activity of cholinergic and noradrenergic neuromodulator systems. These systems regulate the level of cortical arousal and therefore perception, attention, and memory. Here, we tested how different types of pupil size variance (prestimulus baseline and prestimulus hippus power) may correlate with behavioral and event-related potentials (ERPs). We recorded pupil size and ERPs while participants were presented with a series of words and then asked whether the words had been in the initial list when they were later presented intermixed with unpresented words. We found that a smaller prestimulus baseline pupil size during the study phase was associated with better memory performance. Study items also evoked a larger P3 response at presentation and a greater old/new memory ERP effect at test when prestimulus pupil size was small rather than large. Prestimulus hippus power was found to be a between-subjects factor affecting the robustness of memory encoding with less power being associated with a greater old/new memory ERP effect. These results provide evidence relating memory and ERPs to variables defined on pupil size that are thought to reflect varying states of parasympathetic and sympathetic arousal.

Event-related potential studies of cross-situational word learning in four-year-old children

Young children learn word-referent links in cross-situational learning paradigms despite uncertainty as to a given word’s correct referent on individual exposures. However, the semantic status of these word-referent links is unknown. Here, we used a novel event-related potential (ERP) testing approach to investigate whether children showed electrophysiological signatures of semantic representations following a typical cross-situational learning paradigm. In Study 1, 20 4-year-old children (mean age: 51.35 months) learned eight new word-object pairs in a cross-situational learning task which included familiar object labeling before training. Then, they completed an ERP task which involved seeing pictures of the novel objects and then hearing words that were either congruent or incongruent with the word-referent association that was trained. Results showed a robust N400 ERP effect, thereby providing evidence for having acquired a semantic representation during the cross-situational learning paradigm. Children also showed good performance on a comprehension test approximately 20 min after training. In a second study, a different sample of 20 4-year-old children (mean age: 52 months) completed the same cross-situational task but without the initial familiar word pretraining. Here, we did not see the N400 effect we saw in Study 1, but children still showed good performance on the delayed comprehension test. We conclude that rapid semantic encoding can occur during cross-situational learning, but that pretraining on the structure of the paradigm may be critical for facilitating that encoding. We speculate on the mechanisms by which pretraining might have effects and discuss the implications of these findings for early word learning.

Can you change your mind? An ERP study of cognitive flexibility and new evidence integration

Cognitive flexibility is an ability that allows individuals to integrate external evidence into previous expectancies. Individual differences in this ability were examined using Event-Related Potentials (ERPs), focusing on the fact that new evidence can either confirm or disprove an initial impression. Written scenarios prompted to make a prediction while either confirmatory or disconfirmatory evidence followed. A final sentence presented participants with a statement congruent with the prediction likely to have been formed based on the first statement or a statement rather congruent with corrective new evidence. A Bias Against Disconfirmatory Evidence (BADE) test rated participants in cognitive flexibility. ERPs revealed that whereas individuals overall typically reacted to unexpected endings (a classical N400 effect) within the confirmatory evidence condition, higher cognitive flexibility scores were associated with smaller N400 effects. Furthermore, individuals showed larger P600s for disconfirmatory than confirmatory evidence conditions, regardless of the final target ending. This result indexes reanalysis processes whenever disconfirmatory evidence was present. Regression analysis of BADE scores and ERP effects are presented and discussed. Late ERP components are sensitive enough to detect new evidence integration capabilities and thus provide a good implicit measure of cognitive flexibility.