N400 Amplitude Research Articles

Negative world views after trauma: Neurophysiological evidence for negative expectancies.

Negative views of both the self and the world are commonly seen in individuals who have suffered psychological trauma. These negative cognitions are thought to be significant as they are likely to play a critical role in furthering, if not promoting, other symptoms and exacerbating the dysfunction sometimes seen after a traumatic event. This has led to the inclusion of "persistent negative beliefs and expectations about oneself or the world" in the DSM-5 (American Psychiatric Association, 2013). Although there is considerable self-report and behavioral evidence for negative biases after trauma, there is less concurrent neurophysiological data. This study used the N400, an event-related potential sensitive to semantic expectancies, to assess negative expectations in a trauma sample. In this study, 39 participants completed an N400 task in which they read ambiguous sentence stems that ended either with a positive final word (Things will turn out . . . fine) or a negative final word (Things will turn out . . . badly). The authors predicted that those trauma survivors with negative cognitions (as measured by the Posttraumatic Cognitions Inventory [PTCI]: Foa et al., 1999) would show N400 amplitudes indicating expectancies for negative endings. Augmenting the previous self-report data, this would provide evidence for negative expectancies that are fairly early and relatively automatic. N400 amplitudes to negative sentence endings were significantly related to negative views of the world as measured by the PTCI. This suggests that negative world views in trauma survivors have demonstrable neurophysiological correlates and impact on expectations in ambiguous situations. (PsycINFO Database Record

Modelling the N400 brain potential as change in a probabilistic representation of meaning.

The N400 component of the event-related brain potential has aroused much interest because it is thought to provide an online measure of meaning processing in the brain. However, the underlying process remains incompletely understood and actively debated. Here we present a computationally explicit account of this process and the emerging representation of sentence meaning. We simulate N400 amplitudes as the change induced by an incoming stimulus in an implicit and probabilistic representation of meaning captured by the hidden unit activation pattern in a neural network model of sentence comprehension, and we propose that the process underlying the N400 also drives implicit learning in the network. The model provides a unified account of 16 distinct findings from the N400 literature and connects human language comprehension with recent deep learning approaches to language processing.

Neural evidence for reduced automaticity in processing emotional prosody among men with high levels of autistic traits

This study aimed to examine individual differences in the integration of emotional prosody when processing semantic meaning in speech among men with high and low levels of autistic traits, as measured by the Autism Spectrum Quotient (AQ). The behavioral and neural responses of high- and low-AQ men during semantic valence judgment were compared. The stimuli were positive or negative words spoken with either happy or sad prosody; in other words, the prosody was either congruous or incongruous to the valence of meaning. Participants were required to judge the (positive vs. negative) valence of word meaning as accurately and as quickly as possible while ignoring emotional prosody. Behavioral results showed that high-AQ men responded significantly more slowly than low-AQ men in all stimulus conditions, indicating lower automaticity in processing emotional speech. Neural data revealed that low-AQ men (but not high-AQ men) had significantly increased N200 and N400 amplitudes for incongruous (compared to congruous) stimuli spoken with happy prosody. Our findings supported our hypotheses that high levels of autistic traits are associated with reduced behavioral automaticity and less differential neural resources allocated to processing emotional speech stimuli with different cognitive demands.

When 2 × 4 is meaningful: the N400 and P300 reveal operand format effects in multiplication verification.

Arithmetic problems share many surface-level features with typical sentences. They assert information about the world, and readers can evaluate this information for sensibility by consulting their memories as the statement unfolds. When people encounter the solution to the problem 3 × 4, the brain elicits a robust ERP effect as a function of answer expectancy (12 being the expected completion; 15 being unexpected). Initially, this was labeled an N400 effect, implying that semantic memory had been accessed. Subsequent work suggested instead that the effect was driven by a target P300 to the correct solutions. The current study manipulates operand format to differentially promote access to language-based semantic representations of arithmetic. Operands were presented either as spoken number words or as sequential Arabic numerals. The critical solution was always an Arabic numeral. In Experiment 1, the correctness of solutions preceded by spoken operands modulated N400 amplitude, whereas solutions preceded by Arabic numerals elicited a P300 for correct problems. In Experiment 2, using only spoken operands, the delay between the second operand and the Arabic numeral solution was manipulated to determine if additional processing time would result in a P300. With a longer delay, an earlier N400 and no distinct P300 were observed. In brief, highly familiar digit operands promoted target detection, whereas spoken numbers promoted semantic level processing-even when solution format itself was held constant. This provides evidence that the brain can process arithmetic fact information at different levels of representational meaningfulness as a function of symbolic format.

FN400 amplitudes reveal the differentiation of semantic inferences within natural vs. artificial domains

Category-based inferences allow inductions about novel properties based on categorical memberships (e.g., knowing all trout have genes [premise] allows us to infer that all fish have genes [conclusion]). Natural (N) and artificial (A) domains are the most obvious and traditional distinctions in categorization. The distinct event-related potential (ERP) responses for N and A domains have not yet been examined during category-based inferences. In this study, the differences between ERP inference parameters within N and A domains were measured during inductive decision processing, while controlling the premise−conclusion similarity and premise typicality between those two domains. Twenty-two adults were asked to make a decision on whether a conclusion was definitely weak, possibly weak, possibly strong, or definitely strong, based on a premise. The behavioral results showed that semantic inferences within the N domain shared similar inductive strength, similar “correct” response rates, and similar reaction times with that within the A domain. However, the ERP results showed that semantic inferences elicited smaller frontal-distributed N400 (FN400) amplitudes within the N domain than within the A domain, which suggested that knowledge of the ontological domain of a category affects category-based inferences, and underlaid the increased categorical coherence and homogeneity in the N as compared to the A categories. Therefore, we have distinguished the cognitive course of semantic inferences between N and A domains.

The nature of first and second language processing: The role of cognitive control and L2 proficiency during text-level comprehension

Text comprehension relies on high-level cognitive processes as it is the ability to revise an erroneous inference. Recent models of language processing hold that native language processing is proactive in nature (highly predictive), whereas processing seems to be weaker in the second language. However, if a prediction fails because unexpected information is encountered, reactive processing is needed to revise previous information. Twenty-four highly proficient late bilinguals were presented with narratives in L1-English and L2-Spanish. Each text demanded the revision of an initial predictive inference. Reading times and N400 amplitude suggested inferential revision is less efficient in the L2 compared to the L1. Importantly, these effects were modulated by individual differences in cognitive control and L2 proficiency. More efficient L1 comprehension was related to a balance between proactive and reactive control and lower L2 proficiency, whereas more native-like L2 comprehension was associated with a strong proactive control and higher L2 proficiency.

Poststroke Depression Biomarkers: A Narrative Review.

Poststroke depression (PSD) is the most prevalent psychiatric disorder after stroke, which is independently correlated with negative clinical outcome. The identification of specific biomarkers could help to increase the sensitivity of PSD diagnosis and elucidate its pathophysiological mechanisms. The aim of current study was to review and summarize literature exploring potential biomarkers for PSD diagnosis. The PubMed database was searched for papers published in English from October 1977 to December 2017, 90 of which met inclusion criteria for clinical studies related to PSD biomarkers. PSD biomarkers were subdivided into neuroimaging, molecular, and neurophysiological. Some of them could be recommended to support PSD diagnosing. According to the data, lesions affecting the frontal-subcortical circles of mood regulation (prefrontal cortex, basal nuclei, and thalamus) predominantly in the left hemisphere can be considered as neuroimaging markers and predictors for PSD for at least 1 year after stroke. Additional pontine and lobar cerebral microbleeds in acute stroke patients, as well as severe microvascular lesions of the brain, increase the likelihood of PSD. The following molecular candidates can help to differentiate PSD patients from non-depressed stroke subjects: decreased serum BDNF concentrations; increased early markers of inflammation (high-sensitivity C-reactive protein, ferritin, neopterin, and glutamate), serum pro-inflammatory cytokines (TNF-α, IL-1β, IL-6, IL-18, IFN-γ), as well as pro-inflammatory/anti-inflammatory ratios (TNF-α/IL-10, IL-1β/IL-10, IL-6/IL-10, IL-18/IL-10, IFN-γ/IL-10); lowered complement expression; decreased serum vitamin D levels; hypercortisolemia and blunted cortisol awakening response; S/S 5-HTTLPR, STin2 9/12, and 12/12 genotypes of the serotonin transporter gene SLC6A4, 5-HTR2a 1438 A/A, and BDNF met/met genotypes; higher SLC6A4 promoter and BDNF promoter methylation status. Neurophysiological markers of PSD, that reflect a violation of perception and cognitive processing, are the elongation of the latency of N200, P300, and N400, as well as the decrease in the P300 and N400 amplitude of the event-related potentials. The selected panel of biomarkers may be useful for paraclinical underpinning of PSD diagnosis, clarifying various aspects of its multifactorial pathogenesis, optimizing therapeutic interventions, and assessing treatment effectiveness.

The Effect of Training-Induced Visual Imageability on Electrophysiological Correlates of Novel Word Processing.

The concreteness effect (CE) describes a processing advantage for concrete over abstract words. Electrophysiologically, the CE manifests in higher N400 and N700 amplitudes for concrete words. The contribution of the stimulus-inherent imageability to the electrophysiological correlates of the CE is not yet fully unraveled. This EEG study focused on the role of imageability irrespective of concreteness by examining the effects of training-induced visual imageability on the processing of novel words. In two training sessions, 21 healthy participants learned to associate novel words with pictures of novel objects as well as electron-microscopical structures and were additionally familiarized with novel words without any picture association. During a post-training EEG session, participants categorized trained novel words with or without picture association, together with real concrete and abstract words. Novel words associated with novel object pictures during the training elicited a higher N700 than familiarized novel words without picture-association. Crucially, this training-induced N700 effect resembled the CE found for real words. However, a CE on the N400 was found for real words, but no effect of imageability in novel words. The results suggest that the N400 CE for real words depends on the integration of multiple semantic features, while mere visual imageability might contribute to the CE in the N700 time window.

The Role of Context in Processing Chinese Three-Character Verb-Object Metaphors: An Event-Related Potential Study.

Whether and how context plays a role in metaphor processing remains a controversial issue. One major theory on metaphor comprehension, the graded salience hypothesis (GSH) model, emphasizes salience as the key factor determining the precedence of semantic access. Using event-related potential technique, the present study examined Chinese metaphors to investigate whether the salient meaning is always processed first regardless of context. The experiment employed a Prime-Target-Probe paradigm. Three-character Chinese verb-object metaphors were used as the Target proceeded by one of the three contexts (the Prime): (1) metaphorical context priming the Target's metaphorical meaning, (2) literal context priming the Target's literal meaning, and (3) irrelevant context as the control condition. The Target was then followed by the Probe, which was always related to the Target (except in the filler condition). Forty participants were asked to judge whether the Target and the following Probe were semantically related. The N400 elicited by the Target showed no contextual effect. The N400 amplitude elicited by the Probe was smaller in the metaphorical priming condition compared with the literal priming condition, while the N400 in the irrelevant control condition was between the other two conditions, demonstrating a clear context effect. In addition, an unexpected P240 component also showed the similar graded pattern. Our results mostly support the GSH model, indicating that the salient meaning invariantly gets activated first before the activation of the nonsalient meaning at the lexical access stage. However, context does play a role in a parallel way either facilitating or suppressing this interpretation in the latter meaning integration stage.

Brain Evoked Potential Analysis of Second Language Acquisition from the Perspective of Neurolinguistics

The current researches on the foreign language vocabulary attrition mainly focuses on the nature, time and order of the attrition of foreign language vocabulary, but there are few experimental researches using new technological means. In this paper, students who are native Chinese speakers are taken as the subjects to conduct two behavioral experiments and event-related potential (ERP) experiments. The results show that subjects have the attrition of foreign language vocabulary. N1 and N400 effect are found in the results of the two experiments, in which both concrete nouns and abstract nouns show the weakening of N1 component and enhancing of the N400 component. In the trend of brain evoked potential, the amplitude of N1 becomes smaller while the amplitude of N400 becomes larger. These results indicate that foreign language vocabulary leave traces in the brain when it is extracted again, and English nouns appears attrition. As the most common word class in English, the attrition time of Chinese learners to this word class is short and the attrition even occurs within three months.

Print-, sublexical and lexical processing in children with reading and/or spelling deficits: An ERP study

Findings on the neurophysiological correlates of developmental dyslexia are mixed, due to the differential conceptualization of the impairment. Studies differ on whether participants with developmental dyslexia are recruited based on reading skills only or reading as well as spelling skills. The current study contrasts the contribution of impaired reading and spelling to ERP correlates of print sensitivity, lexico-semantic access and sensitivity to orthographic regularities. Four groups of children were recruited: isolated reading deficit, isolated spelling deficit, combined reading and spelling deficit, and typically developing. Their neural correlates (EEG) of word, pseudohomophone, and pseudoword reading, as well as false font processing were compared. 1) All groups showed higher N1 amplitudes to letters than to false fonts. 2) Good spellers exhibited more negative N400 amplitudes for meaningless (pseudowords) than for meaningful stimuli (words and pseudohomophones). This effect was not observed in poor spellers. 3) Good readers showed sensitivity to orthographic regularities in a later time window (700–900 ms), whereas this was not the case for poor readers. 1) Print sensitivity is not affected by reading and/or spelling deficit in German-speaking 3rd graders. 2) Spelling deficits are associated with a reduced orthographic lexicon, 3) Reading deficits are associated with atypical use of sublexical information. As this effect was observed after lexico-semantic access, the results are discussed in terms of a possible orthographic reanalysis hypothesis.

Associations between semantic priming and problem behavior in boy with attention deficit hyperactivity disorder

Objective To investigate the semantic priming of boy with attention deficit hyperactivity disorder(ADHD) and explore whether the semantic priming deficits was associated with behavioral problems by event-related potential(ERP). Methods Thirty boy with and without ADHD aged from 7 to 13 years were asked to finish the semantic Semantic judgment task.The study took advantage of t-test(independent-samples) to compare the amplitude and latency of the N400 in both groups, as well as behavioral data.Behavioral problems were assessed by the Achenbach child behavior checklist(CBCL), and Pearson correlation analysis were used to explore the relationship between behavioral problems and semantic priming. Results Under the condition of semantic correlation, the hyperactive factor of CBCL in ADHA group was positively correlated with ERP N400 amplitude (r=0.44, P<0.05) and negatively correlated with reaction accuracy (r=-0.48, P<0.05). Under the semantic irrelevant condition, the latency of ERP N400 in ADHA group was positively correlated with hyperactivity factor (r=0.53, P<0.05)and aggression factor of CBCL(r=0.62, P<0.05). The N400 amplitude of the ADHD group was significant higher than that in the control group under semantic related conditions((-11.36±4.77)μV vs (-7.66±5.24)μV, P=0.006), and the latency of the N400 in ADHD was more delay((369.6±44.09)ms vs (341.27±24.54)ms, P=0.004), and the reaction times(RT) was much longer((936.18±135.03)ms vs (857.78±103.45)ms, P=0.014). The latency of the N400 in ADHD was more delay than that in the control group under semantic irrelevant conditions((383.93±29.66)ms vs (362.33±29.66)ms, P=0.012), and accuracies of ADHD group was lower than that of control group(0.43±0.39 vs 0.81±0.23, P<0.01). Conclusion The present result indicates that children with ADHD exhibit a deficit in the semantic priming mechanism, and the deficit is positively correlated with hyperactivity and impulsiveness. Key words: Semantic priming; Attention deficit hyperactivity disorder; Behavior problem; ERP; N400

Crosslinguistic interplay between semantics and phonology in late bilinguals: neurophysiological evidence

We investigated effects of crosslinguistic phonological and semantic similarity on the bilingual lexicon of late unbalanced bilinguals. Our masked priming paradigm used L1 (Russian) words as masked primes and L2 (English) words as targets. The primes and the targets either overlapped – phonologically, semantically, both phonologically and semantically – or did not overlap. Participants maintained the targets in memory and matched them against occasionally presented catch stimuli. N170 and N400 components of the word-elicited high-density ERPs were identified and analysed in signal and source space. Crosslinguistic semantic similarity shortened the reaction times. The semantics-related N400 amplitude difference correlated with individual L2 proficiency, while phonological similarity suppressed the N400 amplitude in the semantically unrelated condition. ERP source analysis suggests that these ERP dynamics are underpinned by cortical generators in the left IFG and the temporal pole. We conclude that the semantic and phonological interplay between L1 and L2 suggest an integrated bilingual lexicon.

Does dynamic information about the speaker's face contribute to semantic speech processing? ERP evidence

Face-to-face interactions characterize communication in social contexts. These situations are typically multimodal, requiring the integration of linguistic auditory input with facial information from the speaker. In particular, eye gaze and visual speech provide the listener with social and linguistic information, respectively. Despite the importance of this context for an ecological study of language, research on audiovisual integration has mainly focused on the phonological level, leaving aside effects on semantic comprehension. Here we used event-related potentials (ERPs) to investigate the influence of facial dynamic information on semantic processing of connected speech. Participants were presented with either a video or a still picture of the speaker, concomitant to auditory sentences. Along three experiments, we manipulated the presence or absence of the speaker's dynamic facial features (mouth and eyes) and compared the amplitudes of the semantic N400 elicited by unexpected words. Contrary to our predictions, the N400 was not modulated by dynamic facial information; therefore, semantic processing seems to be unaffected by the speaker's gaze and visual speech. Even though, during the processing of expected words, dynamic faces elicited a long-lasting late posterior positivity compared to the static condition. This effect was significantly reduced when the mouth of the speaker was covered. Our findings may indicate an increase of attentional processing to richer communicative contexts. The present findings also demonstrate that in natural communicative face-to-face encounters, perceiving the face of a speaker in motion provides supplementary information that is taken into account by the listener, especially when auditory comprehension is non-demanding.

F209. Semantic Processing Abnormalities and Their Relationship to Symptoms in Persons at Clinical High Risk for Schizophrenia: An Event-Related Brain Potential Study

Persons exhibiting clinical high-risk (CHR) symptoms similar to but milder than those of schizophrenia have an elevated risk of developing this disorder. We sought evidence that CHR patients process relationships between meaningful concepts abnormally, similar to what has been observed in schizophrenia, and that these abnormalities are related to psychosis-like symptoms. To probe how meaningful stimuli activate related concepts in semantic memory, we measured the N400 event-related potential (ERP) response. We hypothesized that the normal reduction in N400 amplitude for stimuli that are more related to a preceding one is decreased in CHR patients, and that this abnormality correlates with psychosis-like symptoms.

Lonely Individuals Do Not Show Interpersonal Self-Positivity Bias: Evidence From N400.

Self-positivity bias is one of the well-studied psychological phenomena, however, little is known about the bias in the specific dimension on social interaction, which we called herein interpersonal self-positivity bias—people tend to evaluate themselves more positively on social interactions, prefer to be included rather than to be excluded by others. In the present study, we used a modified self-reference task associated with N400 to verify such bias and explore whether impoverished social interaction (loneliness) could modulate it. Findings showed that exclusion verbs elicited larger N400 amplitudes than inclusion verbs, suggesting that most people have interpersonal self-positivity bias. However, loneliness was significantly correlated with N400 effect, showing those with high scores of loneliness had smaller differences in the N400 than those with lower scores. These findings indicated impoverished social interaction weakens interpersonal self-positivity bias; however, the underlying mechanisms need to be explored in future research.

P3-1-10. Interference effect of personality characteristics on language processing with background music: An event related potential study

In an attempt to evaluate the effect of background language reference, we examined the event-related potential (ERP) elicited by reading comprehension while listening to popular song. The subjects were 14 healthy Japanese speakers (21.3 ± 0.8 yrs). ERPs were recorded during judgment of grammatical tenses in English (Et task) or Japanese (Jt task) when exposed to English (Em condition) or Japanese (Jm condition) vocal music. The resultsrevealed a differential pattern of N400 component for native and non-native language processing. Thus, the amplitude of N400 was significantly larger in Et task compared with Jt task regardless of the language of background music (p = .003). Also, the amplitude in Jm condition of Et task showed a positive correlation with the attention deficit hyperactivity disorder (ADHD) index of the subject-rated Conners’ Adult ADHD Rating Scales (CAARS) (F3: r = .625, p = .017, F4: r = .584, p = .028). These findings suggest that the non-native language processing with background music is more detrimentally affected by the behavioral characteristics of ADHD.

The temporal features of vertical spatial metaphor processing after moral disgust priming

Objective To explore the time characteristics and neural mechanism of processing vertical spatial metaphor after the activation of moral disgust, by applying event-related potential technique (ERPs) and semantic priming paradigm. Methods Totally 22 healthy college or graduate students were randomly selected from a university in Henan Province. A dual word priming paradigm was used to present priming words (moral disgust words and non moral disgust words). Then the target words (neutral words above or on the bottom of the screen) were presented, and the subjects were asked to judge the font structure of the target words. Processing feature was explored by investigating the differences in EEG indexes of different combinations. Results The interaction between the starting stimulation of the correct rate and the target stimulation in the behavior data was significant (F=20.40, P<0.01). In EEG data, compared with immoral aversion stimuli(P2: (0.81±0.45)μV, N400: (-4.43±0.58)μV), after the onset of moral abuses(P2: (-1.31±0.40)μV, N400: (-5.04±0.60)μV), the larger P2 (F=3.96, P<0.05) and larger N400 (F=10.73, P<0.01) amplitudes were induced in the related brain regions after the emergence of neutral words at the bottom of the screen. Conclusion The analysis of behavior and EEG data indicates that, compared with immoral disgust, moral abuses show a higher semantic connection with metaphorical moral, and metaphorical immoral shows lower semantic connection. The individual is more inclined to metaphorical morality to relieve and release the feeling of disgust and maintain a good self-moral image. Key words: Disgust; Vertical spatial metaphor; Spatial representation; ERPs

He catapulted his words from the dais: An ERP investigation of novel verbal metaphors

Many ERP studies have highlighted greater semantic processing difficulty for novel metaphors than for literal expressions, reflected by a more negative N400. However, most of these findings were for nominal metaphors, and studies have rarely looked at other types of metaphors, such as verbal predicative metaphors, which involve the metaphorical use of verbs in verb/patient expressions. The aim of the present study was thus to investigate the nature and time course of the cognitive processes involved in the comprehension of novel predicative metaphors. Participants were asked to make semantic judgments about metaphorical (“to catapult the words”), literal (“to catapult the stones”) and meaningless (“to color dust”) expressions. Results revealed greater N400 amplitude for meaningless expressions than for either literals or metaphors, and showed that literals and metaphors differed at posterior right electrodes. Late frontal positivity was also observed. This was greater for novel predicative metaphors than for either literal or meaningless expressions at frontal electrodes.

Semantic Ambiguity Resolution in Patients With Bipolar Disorder-An Event-Related Potential Study.

Deficits in inhibitory function are assumed to underlie psychopathology in bipolar disorder (BD), especially in states of mania. A subdomain of inhibition, semantic inhibition (SI), referring to the suppression of irrelevant word meanings, may underlie formal thought disorder, such as flights of ideas. In the present study, we investigated SI in patients with BD during semantic ambiguity resolution using behavioral and event-related potential (ERP) measures. We presented 14 patients with BD with current manic, hypomanic, or mixed clinical states and 28 healthy controls sequentially with word triplets containing either a homonym (e.g., “organ”) or a comparable unambiguous word (e.g., “piano”). Participants were instructed to make a decision whether or not the target word was related to the meaning field of the first two words. The inappropriate homonym meaning had to be inhibited to correctly perform the target decision. In addition to reaction times (RT) and error rates (ER), the N400 ERP component to the target, an electrophysiological index of semantic processing, was analyzed as measure of the amount of SI that had taken place. Analyses of the behavioral data revealed that BD patients exhibited an overall worse performance in terms of RT and ER. In the ERP data, we found differences in N400 amplitude to ambiguous and unambiguous conditions over the right hemisphere in patients with BD depending on target congruence: In incongruent trials, N400 amplitude was smaller in ambiguous than in unambiguous words. In congruent trials, in contrast, N400 amplitude was larger in ambiguous than in unambiguous words. Such ERP differences between ambiguous and unambiguous words were absent in controls. We conclude that N400 amplitude differences in the ambiguous and unambiguous conditions of the BD group may reflect insufficient suppression of irrelevant homonym meanings in the right hemisphere. Disturbed SI processes might contribute to formal thought disorder in BD.