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Self-knowledge is a type of personal semantic knowledge that concerns one’s self-image and personal identity. It has most often been operationalized as the summary of one’s personality traits (“I am a stubborn person”). Interestingly, recent studies have revealed that the neural correlates of self-knowledge can be dissociated from those of general semantic and episodic memory in young adults. However, studies of “dedifferentiation” or loss of distinctiveness of neural representations in ageing suggest that the neural correlates of self-knowledge might be less distinct from those of semantic and episodic memory in older adults. We investigated this question in an event-related potential (ERP) study with 28 young and 26 older adults while they categorised personality traits for their self-relevance (self-knowledge conditions), and their relevance to certain groups of people (general semantic condition). Participants then performed a recognition test for previously seen traits (episodic condition). The amplitude of the late positive component (LPC), associated with episodic recollection processes, differentiated the self-knowledge, general semantic, and episodic conditions in young adults, but not in older adults. However, in older adults, participants with higher composite episodic memory scores had more differentiated LPC amplitudes across experimental conditions. Moreover, consistent with the fact that age-related neural dedifferentiation may be material and region specific, in both age groups some differences between memory types were observed for the N400 component, associated with semantic processing. Taken together, these findings suggest that declarative memory subtypes are less distinct in ageing, but that the amount of differentiation varies with episodic memory function.

Social comparison is a common behavior that largely determines people’s experience of decision outcome. Previous research has showed that interpersonal relationship plays a pivotal role in social comparison. In the current study, we investigated whether the manipulation of context-based relationship would affect participants’ comparison of self-outcome and other-outcome. Participants first finished a trust game with likeable (dislikeable) partner and then they were involved in a gambling task and observed the outcomes for themselves and for partners. According to self-reports, participants were more satisfied with likeable partner’s gains than losses only when they received gains, but they were always more satisfied with dislikeable player’s losses compared to gains. Event-related potentials including the feedback-related negativity (FRN), P3 and late positive component (LPC) were sensitive to context-based relationship. Specifically, the prediction error signal (indexed by the FRN) was largest when participants received losses but dislikeable player received gains. Meanwhile, the P3 indicates that participants had stronger motivation to outperform dislikeable player. Finally, the LPC was larger when participants received the same outcomes with dislikeable players. In general, our results support the key point of the self-evaluation maintenance model that personal closeness modulates subjective sensitivity when drawing a comparison of one’s outcomes with other’s outcomes.

Biological relevance may influence the neural response towards images which depict attack intent. In the present study, images featuring reptiles and firearms were employed as target and flanking stimuli in a modified version of the affective Flanker task. Forty-two participants (21 male) completed the modified Flanker task as EEG was recorded. Congruency effects in reaction times were more consistently observed for arrays with firearm targets than for arrays with reptile targets. Arrays with neutral targets (i.e., water pistols, turtles) evoked more negative mean N2 (250–400 ms) amplitudes than those with attack targets (i.e., attacking snakes, aimed handguns), while arrays with aimed handgun targets elicited more positive mean activity for the late positive component (LPC; 450-650 ms) compared to arrays with water pistol or reptile targets. Congruency effects were also found in N2 activity for arrays with firearm targets and reptile Flankers. In addition, LPC amplitude for incongruent arrays with attack targets and neutral Flankers was reduced compared to congruent attack arrays. These findings suggest that biological relevance influences interference processing (the N2) and intersects with attack intent during the later stages of picture processing (the LPC).

Behavioral data on episodic recollection in autism spectrum disorders (ASD) point limited relational memory functioning. However, the involvement of successive memory processes in the profile of episodic memory in ASD needs more study. Here, we used event-related potentials (ERP) to investigate the time course of episodic recollection with an associative recognition paradigm with picture pairs. Twenty-two participants with ASD and 32 with typical development (TD), all right-handed, were included. Behavioral results confirmed difficulties in correctly recognizing identical pairs in the ASD relative to TD group. We found an unexpected amplitude decrement on the P2 (220-270 msec) and FN400 (350-470 msec) potentials, suggesting diminished priming and familiarity effects in the ASD relative to TD group. However, ERP data revealed that the recognition of associative information relies on the same electrophysiological process (old/new effect in the 600-700-msec late positive component) in ASD participants as in TD ones, with a parietal extension in the ASD group. These results suggest that the electrophysiological processes of associative recognition are qualitatively similar in individuals with and without ASD but may differ quantitatively. This difference may be driven by the reduced early processing of picture pairs that may in turn lead to their diminished integration into the semantic memory system, being partially compensated by a greater involvement of associative memory during the recollection process. Other studies would be useful to go further in identifying these cognitive processes involved in atypical recognition in ASD and their neural substrates. Autism Res 2020, 13: 1998-2016. © 2020 International Society for Autism Research and Wiley Periodicals LLC LAY SUMMARY: We identified diminished performance on the associative recognition of picture pairs in adolescents and young adults with autism when compared to typical development. Electrophysiological data revealed qualitative similarities but quantitative differences between-group, with diminished priming and familiarity processes partially compensated by an enhanced parietal recollection process.

The current study aims to investigate how Field independent (FI) and Field-dependent (FD) cognitive styles modulate bilingual language control during a joint language switching task. The cognitive styles were measured by the Group Embedded Figures Test (GEFT). The FI group with a preference for autonomous information processing was sensitive to role switching earlier at the cue stage, eliciting a more negative-going N2 in the cross-person condition than in the within-person condition. While the FD group, with a holistic processing style, discerned such role switching later, inducing a more positive-going late positive component (LPC) in the cross-person condition. In addition, the FD group exercised more cognitive control to suppress the interference from the L1 lemma, indexed by larger LPC amplitudes for L2 switch trials than L1 switch trials in the within-person condition. These findings suggest that FDI cognitive styles modulate bilingual language control mechanism through different manners of information processing.

BACKGROUND Item memory and source memory are differently processed with both behavioral and event-related potential (ERP) evidence. Reality monitoring, a specific type of source memory, which refers to the ability to differentiate external sources from internal sources, has been drawing much attention. Among factors that have an impact on reality monitoring, fluency has not been well-studied. Therefore, the current study aimed to investigate whether fluency could affect reality monitoring, through observations on both behavioral performance and electrophysiological patterns. MATERIAL AND METHODS Adopting ERP techniques, participants were required either to watch the presentation of a name/picture pair, or to imagine a picture for each displayed name, once (low fluency) or twice (high fluency). Later they completed a reality monitoring task of identifying names as perceived, imagined, or novel items. Behavioral performance was measured, and ERP waveforms were recorded. RESULTS Behaviorally, high fluency items were faster and more accurately attributed to the sources than low fluency items. ERP waveforms revealed that late positive component (LPC) occurred for all 4 types of items, while imagined items of low fluency did not record a robust FN400 or late frontal old/new effect. CONCLUSIONS As results revealed, the factor of fluency does influence reality monitoring in terms of accuracy and responding speed. Meanwhile, for imagined items of low fluency, the absence of FN400 and frontal old/new effect also suggests the sensitivity of reality monitoring to fluency, because these representatives of familiarity-based processing and post-retrieval monitoring are inevitably involved in the process of differentiating internal source from external source.

Successful episodic memory requires binding of event details across spatial and temporal gaps. The neural processes underlying mnemonic binding, however, are not fully understood. Moreover, although acute stress is known to modulate memory, if and how stress changes mnemonic integration across time and space is unknown. To elucidate these issues, we exposed participants to a stressor or a control manipulation shortly before they completed, while electroencephalography was recorded, an encoding task that systematically varied the demands for spatial and temporal integration. Associative memory was tested 24 h later. While early event-related potentials, including the P300 and Late Positive Component, distinguished different levels of spatiotemporal discontinuity, only later Slow Waves were linked to subsequent remembering. Furthermore, theta oscillations were specifically associated with successful mnemonic binding. Although acute stress per se left mnemonic integration largely unaffected, autonomic activity facilitated object memory and glucocorticoids enhanced detail memory, indicative for mnemonic integration. At the neural level, stress amplified the effects of spatiotemporal discontinuity on early information processing. Together, our results indicate that temporal and spatial gaps recruit early neural processes, providing attentional resources. The actual binding success, however, appears to depend on later processes as well as theta power and may be shaped by major stress response systems.

Theory of mind (ToM) refers to the ability to infer others’ mental states. In our everyday lives, we need to interact constantly and appropriately with others. Not only is ToM involved in understanding others’ mental states (other-oriented mental inferences), but it also helps to keep our own mental states (self-oriented mental inferences). In this study, we designed a false-belief task using event-related potential (ERP) measures to investigate the dynamic differences between the two types of mental inferences. In the false-belief task, participants were prompted with a cue to attribute a belief to either themselves (self-oriented) or another person (other-oriented). Results showed that other-oriented false-belief attribution elicited a larger late positive component (LPC; 320~440 ms post-cue onset) than the one elicited by self-oriented attribution at bilateral parieto-occipital electrodes, and also a larger late negative component (LNC; 380~500 ms post-cue onset) at frontal-central electrodes. In addition, the difference in amplitude of LPC between the two types of false-belief attribution was positively correlated with self-reported autistic traits measured by the Autism Spectrum Quotient (AQ). Based on prior literature, we propose that the LPC and LNC reflect the processes of self-other distinction and conflict control, respectively. Moreover, the difficulty in distinguishing other from the self is related to one’s degree of autistic traits.

The first theoretical model on the neurophysiological basis of the N400: the deflection reflects layer I dendritic plateaus on a preparatory state of synaptic integration that precedes layer V somatic burst firing for conscious identification of the higher-order features of the stimulus (a late positive shift). Plateaus ensue from apical disinhibition by vasoactive intestinal polypeptide-positive interneurons (VIPs) through suppression of Martinotti cells, opening the gates for glutamatergic feedback to trigger dendritic regenerative potentials. Cholinergic transients contribute to these dynamics directly, holding a central role in the N400 deflection. The stereotypical timing of the (frontal) glutamatergic feedback and the accompanying cholinergic transients account for the enigmatic "invariability" of the peak latency in the face of a gamut of different stimuli and paradigms. The theoretical postulations presented here may bring about unprecedented level of detail for the N400 deflection to be used in the study of schizophrenia, Alzheimer's disease and other higher-order pathologies. The substrates of a late positive component, the Mismatch Negativity and the Semantic Prediction Potentials are also surveyed.

Previous studies have reported lowered implicit self-esteem at the behavioral level among depressed individuals. However, brain responses related to the lowered implicit self-esteem have not been investigated in people with depression. Here, event-related potentials were measured in 28 dysphoric participants (individuals with elevated amounts of depressive symptoms) and 30 control participants during performance of an implicit association task (IAT) suggested to reflect implicit self-esteem. Despite equivalent behavioral performance, differences in brain responses were observed between the dysphoric and the control groups in late positive component (LPC) within 400-1,000 ms poststimulus latency. For the dysphoric group, self-negativity mapping stimuli (me with negative word pairing and not-me with positive word pairing) induced significantly larger LPC amplitude as compared to self-positivity mapping stimuli (me with positive pairing and not-me with negative pairing), whereas the control group showed the opposite pattern. These results suggest a more efficient categorization toward implicit self-is-negative association, possibly reflecting lower implicit self-esteem among the dysphoric participants, in comparison to the controls. These results demonstrate the need for further investigation into the functional significance of LPC modulation during IAT and determination of whether LPC can be used as a neural marker of depressive-related implicit self-esteem.

This study examined whether emotion responses during reading are co-constituted by lexical items and the preceding context. Event-related potentials to coherent emotion and neutral words finishing sentences with or without strong constraint for the incoming valence were analyzed. Typical frontal P200 and posterior late positive component (LPC) emotion responses were seen to emotion words relative to neutral words in the neutral context, indicating heightened attention allocation and further valence analysis induced by word-level emotionality. With emotional bias in the context, words elicited reduced N400 responses, indicating facilitated semantic processing. Critically, we obtained evidence for contextualized emotion responses during coherent sentence comprehension. With active anticipation of the incoming emotionality (evidenced by the frontal positivity to plausible emotionally unpredicted words), enhanced P200 and LPC responses were seen to neutral words in emotional contexts. These findings demonstrated that, like word emotionality, emotion-constraining contexts could similarly engage motivational circuits and attention resources, affecting early perception and later further affective evaluation of the incoming information, even for emotionally neutral words. Despite the seeming similarity, multiple routes may be involved for giving rise to these neurophysiological reactions during emotion processing - while lexically driven LPCs were significantly correlated with empathy, contextually driven LPCs were not. Together, these findings provide support for contextualized emotion responses during congruent sentence reading when explicit emotional judgment on the materials is not required. These findings also provide an initial understanding about how these responses are mediated by empathy - an important aspect of human ability to perceive emotion.

Adaptation to sensory events of long or short duration leads to a negative aftereffect, in which a new target event (of median duration) following the adaptation will be perceived to be shorter or longer than is actually the case. This illusion has been observed in visual, auditory, and tactile modalities. This study used event-related potentials (ERPs) to examine the tactile duration aftereffect, using the contingent negative variation (CNV) and the late positive component (LPC) as a way to characterize the temporal processes. The tactile duration adaptation was found to induce a significant aftereffect within a somatotopic framework. Moreover, the CNV in the contralateral scalp and the LPC in the fronto-central scalp were both modulated by the tactile duration adaptation. Specifically, adaptation to a short tactile duration increased the CNV and LPC amplitudes, whereas adaptation to a long tactile duration decreased them. This modulation was contingent on the topographic distance between fingers, which was only observed when the adapting and test fingers were consistent or adjacent, but not homologous. In sum, these results reveal a coherent behavioral-electrophysiological link in the somatotopically organized tactile duration aftereffect.

While proactive inhibition (PI) frequently occurs in response to novel stimuli due to interference from previously learned information, shifts in semantic category on a preceding trial lead to the attenuation of learning interference effects such as PI, resulting in significantly improved performance on short-term memory tasks. This study examined how the release from PI also leads to a reduction in semantic inhibition, as measured primarily through an event-related potential (ERP) electroencephalography (EEG) design. The study used Chinese characters denoting different categories (word nouns for categories such as plants, clothes, and flowers) to test short-term memory recall in a control group (same category/no PI release) and experimental group (different category/PI release). Both behavioral data (recall accuracy) and ERP responses for the N400 and Late Positive Component (LPC) at frontal, central, and parietal electrode sites were collected. Behaviorally, recall accuracy declined continuously on the initial three consecutive trials, regardless of group, while recall increased significantly on the last trial specifically for the experimental group, due to the shift in semantic category. We reported a significant interaction between group and electrode site for the LPC component, indicating that inhibition effects were still active for both groups at the initial memory encoding stage (corresponding to N400), with inhibition release in the experimental group occurring through later LPC processing. These results provide electrophysiological evidence that release from PI can be distinguished from semantic forms of processing through changes in amplitude over the course of learning.

It is well established that identification of words in noise improves when it is preceded by a semantically related word, but comparatively little is known about the effect of subsequent context in guiding word in noise identification. We build on the findings of a previous behavioural study (Chan & Alain, 2019) by measuring neuro-electric brain activity while manipulating the semantic content of a cue that either preceded or followed a word in noise. Participants were more accurate in identifying the word in noise when it was preceded or followed by a cue that was semantically related. This gain in accuracy coincided with a late positive component, which was time-locked to the word in noise when preceded by a cue and time-locked to the cue when it followed the word in noise. Distributed source analyses of this positive component revealed different patterns in source activity between the two temporal conditions. The effects of relatedness also generated an event-related potential modulation around 400 ms (N400) that was present at cue presentation when it followed the word in noise, but not for the word in noise when preceded by the cue, consistent with findings regarding its sensitivity to signal degradation. Exploratory analyses examined a subset of data based on participants’ subjective perceived clarity, which revealed a posterior deflection over the left hemisphere that showed a relatedness effect. We discuss these findings in light of research on prediction as well as a reflective attention framework.

Musical training is required for individuals to correctly label musical modes using the terms "major" and "minor," whereas no training is required to label these modes as "happy" or "sad." Despite the high accuracy of nonmusicians in happy/sad labeling, previous research suggests that these individuals may exhibit differences in the neural response to the critical note-the note (the third of the relevant key) that defines a melody as major or minor. The current study replicates the presence of a late positive component (LPC) to the minor melody in musicians only. Importantly, we also extend this finding to examine additional neural correlates of critical notes in a melody. Although there was no evidence of an LPC response to a second occurrence of the critical note in either group, there was a strong early right anterior negativity response in the inferior frontal gyrus in musicians in response to the first critical note in the minor mode. This response was sufficient to classify participants based on their musical training group. Furthermore, there were no differences in prefrontal asymmetry in the alpha or beta bands during the critical notes. These findings support the hypothesis that musical training may enhance the neural response to the information content of critical note in a minor scale but not the neural response to the emotional content of a melody.

The preference for high-over low-calorie food and difficulties in inhibiting the desire for high-calorie food are important factors involved in unhealthy food choices. Here, we explored posthypnotic suggestions (PHS), aiming to increase the desire for vegetables and fruits, as a possible new tool to induce a preference for low-calorie food. Following the termination of hypnosis, PHS was activated and deactivated in counterbalanced order, while event-related brain-potentials were recorded. Two tasks were administered, a food-face classification measuring implicit food preferences, where stimuli were categorized as showing food items or faces, and a Go-NoGo task measuring inhibition, where food items were selected as being appropriate for making a salad or not. In the food-face classification task without PHS, the early visual P1 component, a marker of stimulus reward-associations, was larger in response to high-than low-calorie food pictures; PHS eliminated this difference. PHS also yielded faster RTs and larger amplitudes of a late positive component in low-versus high-calorie items. Hence, PHS appeared to neutralize the positive perceptual bias toward high-calorie food items and enhance the effective processing of low-calorie items by increasing motivated attention. In the Go-NoGo task, PHS decreased the NoGo-N2; PHS increased the early Go- and NoGo-P3, possibly by turning low- and high-calorie items more pleasant and unpleasant, respectively, requiring more proactive control to inhibit task-irrelevant food-related emotions. Further, in the Go condition, PHS quickened the rejection of salad-inappropriate high-calorie items and increased the amplitude of late-P3, indicating facilitated classification of high-calorie items and increased response monitoring. Together, PHS effectively increased the preference for low-calorie food and the inhibition of impulses toward high-calorie food; therefore, PHS may be a promising tool for supporting healthy and sustainable food choices.

Contains fulltext : 216594.pdf (Publisher’s version ) (Open Access) Electrophysiological studies on recognition memory have identified several brain signals that are associated with subjective perceived confidence. However, the extent these brain signals reflect a generic process and are independent of the type of information recognized remains an open question. To address this issue, twenty-seven healthy volunteers performed an episodic memory task while their electro-encephalogram (EEG) was recorded. Participants encoded a set of abstract pictures, and subsequently rated their confidence on recognition decisions. Similar to results reported in previous studies using concrete words, we found retrieval-related theta power, FN400 and late positive component (LPC) effects. In contrast to previous studies using verbal material, a subsequent memory effect for encoding-related parietal evoked theta power, sensitive to subjectively perceived memory confidence, was observed. Our findings suggest that memorizing abstract pictures instead of concrete verbal material influences subsequent memory effects, yet does not affect the FN400, LPC and theta power during retrieval. 7 p.

Emotion exerts varied influences on memory. While task-relevant item memory is often enhanced by emotion, associative memory is generally impaired. Unitization is known to improve associative memory, but its effects and mechanisms in protecting associative memory from emotional interference are rather obscure. The current study investigated associative memory by employing experimental manipulation of unitization (vs. nonunitization) encoding strategy and stimulus emotion (neutral, intrinsic negative, and extrinsic negative), combined with event-related potential (ERP) signatures of familiarity (FN400 old/new effects) and recollection (parietal late positive component/LPC old/new effects) in memory recognition. Both behavioral and ERP indices of associative recognition from the nonunitization group confirmed emotional interference in associative memory. Importantly, it was primarily intrinsic (vs. extrinsic) emotion that impeded associative memory. Unitization encoding improved memory performance in general, accompanied by enhanced recollection process and induction of familiarity process, which is typically not involved in associative memory recognition and was indeed absent in the nonunitization group. Importantly, unitization helped to preserve behavioral performance (specifically, response speed though not recognition strength) from interference by intrinsic emotion while largely reversed the detriment of intrinsic emotion on ERP indices of familiarity and recollection processes. Interestingly, a synergy between intrinsic emotion and unitization encoding was observed, which could underpin the facilitation of familiarity process in associative recognition of emotional pairs. Overall, current findings highlight interference by intrinsic emotion in associative memory, which is nonetheless responsive to mitigation by unitization encoding.

Much is still unknown about the potential long-term effects of prenatal methadone and buprenorphine exposure. We examined neural correlates of cognitive control in 19 prenatally methadone and buprenorphine exposed and 21 nondrug exposed children, aged 9-11 years. Children performed a modified version of the Eriksen Flanker task, which taps into selective attention, conflict response, and response inhibition mechanisms. We investigated behavioral responses and the ERP components N1, P2, N2, P3, and the late positive component (LPC). Children in the exposed group showed normal cognitive control function. However, an atypical ERP response related to perceptual and attention allocation processes was found in the exposed group.

The present study aimed to provide electrophysiological evidence about acquiring complex numerical rules when unexpected numbers were presented. Hence, we compared the neural correlates underlying the acquisition of unexpected complex rules (e.g., 12, 14, 18, 24) compared to expected simple rules (e.g., 12, 14, 16, 18). The event-related potential (ERP) results for the rule acquisition process for the third numbers showed that, in contrast to expected simple rules, unexpected complex rules elicited: an enhanced N200, reflecting the detection of a conflict between the expected numbers and the displayed numbers; a decreased P300, indicating a feeling of uncertainty accompanied by identifying numerical regularity; and an increased LPC, reflecting the working-memory updating caused by expectancy violation and rule acquisition. These results describe the precise time course of acquiring novel and complex rules when unexpected numbers were presented.

Negative mood has been found to be a critical trigger for overeating in restrained eaters. The ability to suppress thinking of palatable food cues is crucial to control hedonic eating; nevertheless, little research has been conducted to explore inhibitory control in cognitive processes among restrained eaters. To address this gap, this study primed restrained eaters with negative (n = 23) or neutral emotions (n = 24) and applied a Think/No-think paradigm to explore their retrieval facilitation/suppression ability for food cues, while recording Electroencephalogram (EEG) data. Results indicated that the recall rate of the No-think condition (retrieval suppressing task) was higher than the Think condition (retrieval task). Negative affect did not influence the recall rate, but it did evoke smaller N2 amplitudes, larger P2 and P3 amplitudes, as well as late positive component (LPC) amplitudes. Among these components, P2 evoked by the No-think and Think conditions was larger than the perceptual control condition. Our findings suggested that in negative moods, restrained eaters need to allocate more attentional resources to suppress food cues. The findings further demonstrated that the influence of negative moods appeared at an early stage of cognitive processing and caused a resource depletion in memory suppression. This research provides a neurophysiological basis for understanding emotional influences on the process of restrained eaters’ inhibition control for external food cues.

Developmental dyslexia is a reading disorder that is associated with deficits in phonological processing, where the exact neural basis for those processing deficits remains unclear. In particular, disagreement exists whether degraded phonological representations or an impaired access to the phonological representations causes these deficits. To investigate this question and to trace changes in neurophysiology during the process of reading acquisition, we designed a longitudinal study with event related potentials (ERPs) in children between kindergarten and second grade. We used an explicit word processing task to elicit the late positive component (LPC), which has been shown to reflect phonological processing. A brain-wide analysis of the LPC with an electrode-wise application of mixed effects models showed significantly attenuated amplitudes in the left temporo-parietal region in dyslexic children. Since these differences were only present in the word and not in the picture (i.e. control) condition, the attenuated amplitudes might reflect impaired access to the phonological representations of words. This was further confirmed by the longitudinal development, which showed a rapid increase in amplitude at the beginning of reading instruction and a decrease with continuing automatization, possibly pointing to a progression from grapheme-phoneme parsing to whole word reading. Our longitudinal study provides the first evidence that it is possible to detect neurophysiological differences in the LPC between children with dyslexia and control children in both preliterate and very early stages of reading acquisition, providing new insights about the neurophysiological development and a potential marker of later reading problems., Graphical abstract Image 1, Highlights • First longitudinal study of the late positive component (LPC) • Left temporo-parietal LPC differs between control and dyslexic children. • LPC increase at reading acquisition and decrease with automatization in typical readers. • Dyslexic children do not show this neurophysiological course of development. • Findings might indicate an impaired access to phonological representations.

Individual differences in dimensions of impulsivity personality including disinhibition and sensation seeking modulate approach responses to reinforcing stimuli, such as drugs and money. The current study examined the effects of monetary incentive on both behavioral performance and electrophysiological activity among individuals varying in disinhibition and sensation seeking. The monetary incentive delay (MID) task was completed under electroencephalogram (EEG) recording. Behavioral data showed that higher disinhibition and sensation-seeking were associated with lower performance accuracy. Event-related potential (ERP) data showed that high reinforcement cues elicited a larger late positive component (LPC) than other conditions among high disinhibition participants, indicating its strong emotional influence. Additionally, in the neutral incentive condition, the feedback-related negativity (FRN) elicited by correct outcomes was larger than that elicited by incorrect outcomes in the high disinhibition group, only. This novel finding indicates that high disinhibition participants were less likely to expect correct outcomes compared to incorrect outcomes in the neutral incentive condition. Finally, the P3 component elicited by outcome presentation showed an interaction between two impulsivity dimensions; when disinhibition level was low, the P3 was larger among high than low sensation seeking participants.

Previous studies have found that competitive Scrabble expertise is associated with enhanced performance on visual lexical decision tasks (LDT), particularly for vertically presented stimuli. In the current study, we investigated the underlying mechanisms responsible for this vertical fluency. We examined behaviour and neural activity during LDT in 19 competitive Scrabble players and 18 matched controls. Using event related potentials (ERP), we investigated whether Scrabble expertise modulates the N170, P300, and late positive component (LPC), associated with visual-orthographic processing, working memory, and stimulus classification, respectively. Behavioural results replicated those from previous studies: Scrabble experts were significantly faster than controls to respond to vertical stimuli in LDT. ERP results showed Scrabble experts had larger P300 amplitudes in right parietal electrodes compared to controls, as well as greater differentiation in LPC amplitudes between vertical words and nonwords. These findings suggest that the mechanism underlying vertical fluency in Scrabble experts involves enhanced domain-specific working memory and stimulus classification processes. The results have implications for understanding the flexibility of the adult visual word recognition system, as well as the behavioural and neural consequences of training within this system.

The aim of the present study was to investigate whether age-related brain response alterations during sentence comprehension exist when verbal fluency and intelligence are controlled for. Twenty-four younger and twenty-four older adults with matched verbal fluency, verbal intelligence, years of education, and gender ratio were recruited. They were asked to read congruent (CON) and incongruent (INCON) sentences to make semantic acceptability judgments. A significant group by condition interaction on accuracy was found, showing a significant congruency effect in younger, but not older adults. The ERP results revealed a dynamic temporal-spatial change in older adults. The congruency related N400 effect was reduced and delayed significantly in the older adults compared to the younger adults, and accompanied by different distribution patterns across time windows. The late positive component with more positive-going in the INCON condition than the CON condition was found in older adults only, which did not correlate with the performance, however. The results suggest that with age, there is a decline in semantic processing during sentence comprehension.

Presenting events in a rhythm has been shown to enhance perception and facilitate responses for stimuli that appear in synchrony with the rhythm, but little is known about how rhythm during encoding influences later recognition. In this study, participants were presented with images of everyday objects in an encoding phase before a recognition task in which they judged whether or not objects were previously presented. Blockwise, object presentation during encoding followed either a rhythmic (constant, predictable) or arrhythmic (random, unpredictable) temporal structure, of which participants were unaware. Recognition was greater for items presented in a rhythmic relative to an arrhythmic manner. During encoding, there was a differential neural activity based on memory effect with larger positivity for rhythmic over arrhythmic stimuli. At recognition, memory-specific ERP components were differentially affected by temporal structure: The FN400 old/new effect was unaffected by rhythmic structure, whereas the late positive component old/new effect was observed only for rhythmically encoded items. Taken together, this study provides new evidence that memory-specific processing at recognition is affected by temporal structure at encoding.

Research in visual word recognition has shown that phonological neighborhood density facilitates visual word recognition. The current research was designed to determine the electrophysiological effect of phonological neighborhood density (PND). In two experiments, participants made lexical decisions to words varying on phonological neighborhood while Event-related Potentials (ERPs) were recorded. Behaviorally, the results replicate previous research by showing that words with many phonological neighbors were responded to more rapidly than were words with few phonological neighbors. However, the main contribution of the current research is that it shows an effect of PND on the N400 and Late Positive Component Event-Related Potentials. In contrast to previous reports in the literature, the nature of the effect was such that the N400 was larger to words with few phonological neighbors than to words with many. Experiment 2 replicated these findings and provided estimates of the independent components' time course and source localization. The increased N400 for small neighborhood words is thought to reflect additional semantic processing required for these words due their weaker phonological representations.

The effect of language context on bilingual language control has been widely studied, but research examining how these contexts affect executive control is relatively limited. In the present study, we used EEG to examine how language context in production influences executive control in bilinguals. A single group of unbalanced Chinese-English bilinguals completed a modified Flanker task interleaved with a picture-naming task, such that executive control performance was measured in three contexts: Chinese, English, and mixed-language. Event-related potentials (ERPs) revealed larger N2 amplitudes and smaller P3 and LPC (late positive component) amplitudes for the mixed-language context than the single-language context across both congruent and incongruent trials. Moreover, during the language production task, LPC amplitudes in mixed-language context were smaller than in the single-language contexts. These findings suggest that language contexts modulate both bilingual language control and domain-general executive control.

Retrieval practice effect refers to better long-term retention enhanced by active retrieval compared to re-studying, which has been widely demonstrated. However, controversies remain as to whether the underlying mechanism of this effect could be attributed to semantic elaboration. We investigated whether retrieval practice and elaboration were equivalent by observing the underlying cognitive processes of the two conditions using corresponding event-related potentials measures of associative memory and item memory. Behavioral results showed that retrieval practice induced better associate memory performance than elaborative study. For event-related potential results, an early old/recombined effect (FN400) related to familiarity and a late old/recombined effect (late positive component) related to recollection emerged in the retrieval practice condition, while both were absent in the elaborative study condition. An early recombined/new effect (FN400) appeared in the elaborative study condition, which did not occur in the retrieval practice condition. It could be inferred that retrieval practice promoted the recollection of episodic contexts for later associative memory, while elaborative study strengthened the familiarity of individual item. These findings suggest that retrieval practice and elaboration are two distinctive processes.

Recent event-related brain potential (ERP) experiments have demonstrated parafoveal N400 expectancy and congruity effects, showing that semantic information can be accessed from words in parafoveal vision (a conclusion also supported by some eye-tracking work). At the same time, it is unclear how higher-order integrative aspects of language comprehension unfold across the visual field during reading. In the current study, we recorded ERPs in a parafoveal flanker paradigm, while readers were instructed to read passively for comprehension or to judge the plausibility of sentences in which target words varied in their semantic expectancy and congruity. We directly replicated prior work showing graded N400 effects for parafoveal viewing, which are then not duplicated when the target words are processed foveally. Critically, although N400 effects were not modulated by task goals, a posteriorly distributed late positive component thought to reflect semantic integration processes was observed to semantic incongruities only in the plausibility judgment task. However, this effect was observed at a considerable delay, appearing only after words had moved into foveal vision. Our findings thus suggest that semantic access can be initiated in parafoveal vision, whereas central foveal vision may be necessary to enact higher-order (and task-dependent) integrative processing.

Previous studies have reported that observation pressure and outcome pressure impact working memory, but have not investigated whether they exert different effects on working memory. The neuronal activity in some brain areas encodes task-related information corresponding to working memory across delay periods. Therefore, changes in working memory under pressure can be further verified by exploring neuronal activity changes in brain areas under pressure. In this study, we used an N-back task and event-related potentials to explore whether the two types of pressure exert different effects on working memory. The electrophysiological results revealed that observation pressure-induced P1, P2 and late positive component amplitudes are significantly larger than corresponding outcome pressure-induced amplitudes, and the P3 amplitude induced by low-load working memory is significantly larger than that in the high-load condition. A possible explanation is that observation pressure increases attention focus, whereas outcome pressure increases attention dispersion, and a greater memory load results in more information that must be maintained and updated in working memory. These findings indicate that observation pressure and outcome pressure exert different effects on working memory.

Spaced learning has been shown consistently to benefit memory compared with massed learning, yet the neural representations and processes underlying the spacing effect are still poorly understood. In particular, two influential models (i.e., the encoding variability hypothesis and the study-phase retrieval hypothesis) could both model behavioral performance very well, but they make opposite hypotheses regarding the spacing effect's neural mechanisms. The present study attempted to provide empirical neural evidence to adjudicate these competing hypotheses. Using spatiotemporal pattern similarity (STPS) analysis of EEG data, this study investigated whether and how repetition lags (massed/short-spaced/long-spaced) modulated the STPS's contribution to episodic memory encoding in male and female human participants. The results revealed that greater item-specific STPS in the right frontal electrodes at 543–727 ms after stimulus onset was associated with better memory performance. More importantly, this STPS was larger under the spaced-learning condition than the massed-learning condition and partially mediated the spacing effect on memory performance. In addition, we found that massed learning was associated with stronger repetition suppression in the N400 component that reflected momentary retrieval strength, but reduced activity in the late positive component that was associated with memory retrieval. These results suggest that spaced learning improves long-term memory by increasing retrieval effort and enhancing the pattern reinstatement of prior neural representations, which may be achieved by reducing the momentary retrieval strength as the extended repetition lags might help to eliminate the residual representation in working memory. SIGNIFICANCE STATEMENT As one of the most ubiquitous and fundamental phenomena in the history of memory research, the spacing effect provides an important window into understanding how enduring memory is formed in the brain and how different practice strategies could modulate these mechanisms to affect memory performance. By leveraging the neural representational analysis on scalp EEG data, the current study provides the first empirical data to show that spaced learning enhances memory by improving the spatiotemporal similarity that occurs at a late time window. Our results support the study-phase retrieval hypothesis but not the encoding variability hypothesis and emphasize the role of neural pattern reinstatement in strengthening memory via repeated study.

Prior work using word stimuli has uncovered evidence that encoding focus (i.e., self-focus or other-focus) alters non-diagnostic recollection and the putative ERP correlate of recollection (i.e., the Late Positive Component or LPC; Leynes and Mok, 2017, Brain & Cognition). The present study examined the generality of these effects by testing memory for actions. Participants viewed videos of either a male actor or female actor completing simple actions (e.g., Ride the Elevator; Climb the Stairs). Participants judged how much fun it would be to personally perform the action under the self-focus encoding condition, whereas they rated how much fun the actor had while performing the action in the other-focus encoding condition. At test, participants made source judgments regarding who (i.e., male or female) performed the action. Self- and other-focus encoding had similar effects on all behavioral measures including parameters from Dual Process Signal Detection and Unequal Variance Signal Detection models. Experiment 2 recorded brain activity (event-related potentials) and found that self- and other-focus encoding produced similar recognition and LPC amplitudes. These results suggest that encoding focus did not affect the amount of non-diagnostic recollection because both action types promoted strong recollection. Such results are additional evidence that action memory creates more complex traces as compared with typical lab-based stimuli (i.e., pictures or words) and identifies an important boundary condition for encoding focus effects on recollection.

Overweight or obesity can be accompanied by abnormalities in executive function and related neural markers. The aim of the present study was to investigate the behavioral and neural correlates of food-related decision-making in overweight and normal-weight adults. We used a delayed discounting task (DDT), which requires participants to choose between smaller immediate rewards and larger delayed rewards. In total, 24 overweight adults and 24 normal-weight adults participated; all participants engaged with a food-related DDT, and their responses were measured using event-related potentials (ERPs). In the current study, we take the area under the curve (AUC), number of smaller immediate rewards, and reaction times (RTs) as behavioral indicators of DDT. AUC is an individual's discounting rate, with smaller AUC reflecting more impulsive decision-making. Number of smaller immediate rewards also reflects impulsivity. For ERPs, N2, reward-related positivity, P3, and late positive component (LPC) were investigated. Behavioral results showed smaller AUC, more choice of smaller immediate rewards, and longer RTs in overweight adults than in normal-weight adults. Neural markers showed that overweight adults elicited greater N2 in larger delayed rewards than in smaller immediate rewards and also elicited greater reward-related positivity than normal-weight adults. Moreover, the P3 and LPC mean amplitudes of overweight adults were greater than those of normal-weight adults. Pearson correlation analysis showed that body mass index (BMI) was positively related to P3 and LPC, while AUC was negatively related to P3. The findings thus suggest that overweight adults are more impulsive than normal-weight adults. Moreover, overweight adults might experience more cognitive conflict before their reaction, and they might allocate more cognitive resources to food-related stimuli and might have higher-order cognitive processes more involved in motivation or emotion regarding food-related stimuli. This is the first study investigating ERP correlates of food-related decision-making in overweight adults, and it enriches the theoretical models by providing neural markers for future study.

How do bilinguals freely switch languages in daily life (i.e., voluntary language switching)? Does this involve inhibition of cross-language interference, or does easier lexical access to specific words directly trigger switches to another language? To reveal the underlying mechanism of voluntary language switching, the current study applied transcranial direct current stimulation (tDCS) over the right dorsolateral prefrontal cortex (rDLPFC), an area associated with inhibitory control, to investigate whether and how inhibitory control is involved in voluntary language switching. Interestingly, during the A-tDCS and C-tDCS sessions, bilinguals showed faster naming latencies in repeat trials compared to switch trials, indicating a switch cost. Moreover, the cathodal stimulation exhibited a larger LPC in switching to L2 compared to switching to L1. In contrast, the S-tDCS (sham) session showed no switch cost, faster switch naming latencies compared to the A-tDCS and C-tDCS sessions, and little differences in LPC between switch and repeat trials. Together, these findings suggest that modulating inhibition-related brain regions interferes with voluntary language switching.

The capacity to pay attention is important for the cognitive ability, for example, evaluating an object for its qualities. Attention can selectively prioritize the neural processes that are relevant to a given task. Neuroimaging investigations on human attention are primarily focused on vision to the exclusion of other sensory systems, particularly olfaction. Neural underpinnings of human olfactory attention are still not clearly understood. Here, we combined electroencephalographic measurements of olfactory event related potential with electrical neuroimaging to investigate how the neural responses after inhaling the same odor differ between conditions with varying levels of attention, and, in which brain areas. We examined the neural responses when participants attended to a rose-like odor of phenylethyl alcohol for evaluating its pleasantness versus its passive inhalation. Our results gathered significant evidence for attentional modulation of the olfactory neural response. The most prominent effect was found for the late positive component, P3, of olfactory event related potential within a second from the odor onset. The source reconstruction of this data revealed activations in a distributed network of brain regions predominantly in inferior frontal cortex, insula, and inferior temporal gyrus. These results suggest that the neuronal modulations from attention to olfactory pleasantness may be subserved by this network.

The type of threat shown in an image influences the emotional salience of unpleasant images. Seventy-four participants (21 male) rated high threat, moderate threat, and neutral images featuring reptiles, firearms, or humans as electroencephalographic activity was recorded. The magnitude of P3b amplitudes coincided with the threat level of firearm and human images, whereas scenes of attacking snakes and aimed handguns evoked more positive late positive component (LPC) activity than non-attacking or neutral versions of these same stimuli. The lateralised early posterior negativity (EPN) in temporal occipital regions was most negative for firearms, followed by reptiles, and then humans, while the midline EPN in occipital regions was most negative for reptiles, followed by firearms, and then humans. These findings imply late event-related potential positivity is influenced by social relevance (the P3b) or the level of aggression displayed by the stimulus (the LPC), whereas stimulus type may be indexed by EPN modulation.

Across languages, lexical frequency and age of acquisition (AoA) are important predictors of word reading that are naturally correlated, and both variables have been shown to interact with phonological regularity. Previous behavioral findings in Chinese have shown stronger regularity effects in low frequency relative to high frequency characters. Meanwhile, the arbitrary mapping hypothesis predicts stronger interference effects in late-acquired irregular words. This study examined the neural bases of these phenomena in Chinese using a delayed naming task with 480 single characters. Single-trial ERP analyses were conducted to contrast the interactions of frequency or AoA effects with phonological regularity, while controlling for the other factor. Results showed differential and significant effects of AoA and frequency at the N400 and late positive component (LPC), respectively, indicating their independence. ERP interaction patterns of frequency and regularity in Chinese were observed for the first time in the LPC time window and suggested semantic interference from sublexical units during character reading. Interaction of AoA and regularity at the N400 could be explained by the semantic hypothesis but appeared inconsistent with the arbitrary mapping hypothesis.