N400 Amplitude Research Articles

How do blind people use semantic and phonological cues for spoken word recognition? An ERP study

Spoken word recognition is affected by phonemic and semantic details of speech at pre-lexical and lexical levels. The current study examined how blind people used semantic and phonological cues for spoken word recognition. Thirty blind and twenty-nine age-matched sighted people participated in this study. We manipulated the semantic similarity and phonological similarity between the primes and targets in three experimental conditions: semantic-related with different phonology (S + P-), semantic-unrelated with different phonology (S-P-), and semantic-unrelated with the same phonology (S-P + ). Results showed that blind participants had higher accuracies than sighted individuals in both the S-P- and S-P + conditions. As both groups exhibited larger N400 amplitude in the S-P- versus S + P- conditions, the semantic-unrelated N400 effect was stronger in blind than in sighted participants, suggesting a more sensitive processing of semantic information in blind people. Moreover, sighted participants showed stronger N400 effect in the S-P + than in the S-P- conditions, but blind participants did not, indicating an interference of phonological similarity in spoken word recognition for sighted listeners only. In summary, blind people are more sensitive to semantic cues and less susceptible to phonological similarity interference during spoken word recognition than sighted people.

Event-related potentials support the mnemonic effect of spontaneous insight solution.

The mnemonic effect of insight refers to the situation in which experiencing an "aha" moment when solving problems could improve memory performance for both the question and its solution. The aha experience can be triggered either by external stimuli or by internal solution attempts, namely "induced" or "spontaneous" insight, respectively. Tests of the neural correlates of the insightful memory effect are typically conducted in induced insight paradigms. The neural mechanism of the mnemonic effect of spontaneous insight is unclear. In the present study, the mnemonic effect for spontaneous insight was examined by the event-related potentials (ERPs) technique and behavioral measures. Subjects were required to solve a set of Chinese verbal compound remote-associated tasks (CRA), and performed a recognition test 10min later. The results showed that the spontaneous insight solution elicited a more negative deflection than did the non-insight solution before the button reaction (-800 to -400ms) in the study phase. In the recognition test phase, items which elicited insight during study were recognized faster, compared with non-insight study items. And spontaneous insight solution elicited a more positive deflection than did non-insight solution in the time window from 400 to 700ms after onset of the answer. Moreover, brain-behavior correlations revealed a relationship between N400 amplitude during study and later memory performance which revealed a double-dissociation between items solved with and without insight during study. The different predictions for recognition indicate that the encoding of spontaneous insight may differ from that of non-insight, suggesting that different encoding mechanisms may mediate the encoding of items and solutions found by insight versus non-insight.

Not All Words Are Equally Acquired: Transitional Probabilities and Instructions Affect the Electrophysiological Correlates of Statistical Learning.

Statistical learning (SL), the process of extracting regularities from the environment, is a fundamental skill of our cognitive system to structure the world regularly and predictably. SL has been studied using mainly behavioral tasks under implicit conditions and with triplets presenting the same level of difficulty, i.e., a mean transitional probability (TP) of 1.00. Yet, the neural mechanisms underlying SL under other learning conditions remain largely unknown. Here, we investigated the neurofunctional correlates of SL using triplets (i.e., three-syllable nonsense words) with a mean TP of 1.00 (easy “words”) and 0.50 (hard “words”) in an SL task performed under incidental (implicit) and intentional (explicit) conditions, to determine whether the same core mechanisms were recruited to assist learning. Event-related potentials (ERPs) were recorded while participants listened firstly to a continuous auditory stream made of the concatenation of four easy and four hard “words” under implicit instructions, and subsequently to another auditory stream made of the concatenation of four easy and four hard “words” drawn from another artificial language under explicit instructions. The stream in each of the SL tasks was presented in two consecutive blocks of ~3.5-min each (~7-min in total) to further examine how ERP components might change over time. Behavioral measures of SL were collected after the familiarization phase of each SL task by asking participants to perform a two-alternative forced-choice (2-AFC) task. Results from the 2-AFC tasks revealed a moderate but reliable level of SL, with no differences between conditions. ERPs were, nevertheless, sensitive to the effect of TPs, showing larger amplitudes of N400 for easy “words,” as well as to the effect of instructions, with a reduced N250 for “words” presented under explicit conditions. Also, significant differences in the N100 were found as a result of the interaction between TPs, instructions, and the amount of exposure to the auditory stream. Taken together, our findings suggest that triplets’ predictability impacts the emergence of “words” representations in the brain both for statistical regularities extracted under incidental and intentional instructions, although the prior knowledge of the “words” seems to favor the recruitment of different SL mechanisms.

Lexical selection in bimodal bilinguals: ERP evidence from picture-word interference

ABSTRACT The picture word interference (PWI) paradigm and ERPs were used to investigate whether lexical selection in deaf and hearing ASL-English bilinguals occurs via lexical competition or whether the response exclusion hypothesis (REH) for PWI effects is supported. The REH predicts that semantic interference should not occur for bimodal bilinguals because sign and word responses do not compete within an output buffer. Bimodal bilinguals named pictures in ASL, preceded by either a translation equivalent, semantically-related, or unrelated English written word. In both the translation and semantically-related conditions bimodal bilinguals showed facilitation effects: reduced RTs and N400 amplitudes for related compared to unrelated prime conditions. We also observed an unexpected focal left anterior positivity that was stronger in the translation condition, which we speculate may be due to articulatory priming. Overall, the results support the REH and models of bilingual language production that assume lexical selection occurs without competition between languages.

Brain Vital Signs Detect Information Processing Differences When Neuromodulation Is Used During Cognitive Skills Training.

Background: Neuromodulation through translingual neurostimulation (TLNS) has been shown to initiate long-lasting processes of neuronal reorganization with a variety of outcomes (i.e., neuroplasticity). Non-invasive TLNS is increasingly accessible through the Portable Neuromodulation Stimulator (PoNS®), a medical device that delivers electrical stimulation to the tongue to activate the trigeminal (V) and facial (VII) cranial nerves. Anecdotal reports from previous clinical studies have suggested incidental improvements in cognitive function. To objectively explore this observation, we examined TLNS-related effects on the semantic N400 brain vital sign cognitive response during cognitive skills training in healthy individuals.Methods: Thirty-seven healthy volunteers were randomized to receive simultaneous TLNS (treatment) or no TLNS (control) while undergoing cognitive skills training. Cognitive training was conducted for two 20-min sessions (morning and afternoon/evening) over 3 consecutive days. Brain vital signs were evaluated at baseline, Day 1, and Day 3. Analyses focused on cognitive processing as measured by N400 changes in amplitude and latency.Results: Over the 3-day course of cognitive training, the N400 amplitude decreased significantly in the control group due to habituation (p = 0.028). In contrast, there was no significant change in the TLNS treatment group.Conclusion: TLNS led to a sustained N400 response during cognitive skills training, as measured by the brain’s vital signs framework. The study findings suggest differential learning effects due to neuromodulation, consistent with increased attention and cognitive vigilance.

Gender-dependent variations in optical illusions: evidence from N400 waveforms

Objective: The cognitive mechanisms (especially the gender-related ones) underlying optical illusion processing remain elusive. Since the N400 component of event-related potentials (ERPs) is an index of the semantic integration of information processing tasks, the present study focuses on gender-related differences in N400 waveforms elicited during the reasoning process applied to reach a valid conclusion of optical illusions engaging working memory (WM). Approach: Fifty-one healthy participants (28 males, age = 34.25 years ± 10.25, years of education = 16.00 years ± 1.78; and 23 females, age = 33.43 ± 7.93, years of education = 15.56 ± 1.82) were measured. The N400 ERP component was evoked by 39 optical illusions adjusted to induce WM. We compared brain activation patterns while participants maintained conclusions of the optical illusions in WM. The N400 of ERPs was recorded during the WM phase, during which participants were required to draw a logical conclusion regarding the correctness of the optical illusions. Main results: Analysis revealed that females compared to males exhibited significantly increased N400 amplitudes located at parietal and occipital sites, whereas males exhibited significantly higher N400 amplitudes located at frontal areas. Furthermore, females compared to males demonstrated significantly prolonged latencies of the N400 component located at right frontotemporal abductions. Significance: These results suggest that coupling of optical illusions with WM engages distinct gender-related variations of brain semantic processing as reflected by the N400 ERP component. Based on the dual process account, our study gives support to the notion that women tend to employ a more deliberate and slower semantic reasoning than the men who tend to employ an automatic and fast one. Topographically, within the network sub-serving the semantic operation, the posterior brain areas responsible for sensorimotor integration-related processes elicit a greater brain activation among females while the anterior brain areas responsible for control and storage/retrieval operation elicit a greater brain activation among males.

Picture-naming in American Sign Language: an electrophysiological study of the effects of iconicity and structured alignment

ABSTRACT A picture-naming task and ERPs were used to investigate effects of iconicity and visual alignment between signs and pictures in American Sign Language (ASL). For iconic signs, half the pictures visually overlapped with phonological features of the sign (e.g. the fingers of CAT align with a picture of a cat with prominent whiskers), while half did not (whiskers are not shown). Iconic signs were produced numerically faster than non-iconic signs and were associated with larger N400 amplitudes, akin to concreteness effects. Pictures aligned with iconic signs were named faster than non-aligned pictures, and there was a reduction in N400 amplitude. No behavioural effects were observed for the control group (English speakers). We conclude that sensory-motoric semantic features are represented more robustly for iconic than non-iconic signs (eliciting a concreteness-like N400 effect) and visual overlap between pictures and the phonological form of iconic signs facilitates lexical retrieval (eliciting a reduced N400).

N400 amplitude, latency, and variability reflect temporal integration of beat gesture and pitch accent during language processing

This study examines how across-trial (average) and trial-by-trial (variability in) amplitude and latency of the N400 event-related potential (ERP) reflect temporal integration of pitch accent and beat gesture. Thirty native English speakers viewed videos of a talker producing sentences with beat gesture co-occurring with a pitch accented focus word (synchronous), beat gesture co-occurring with the onset of a subsequent non-focused word (asynchronous), or the absence of beat gesture (no beat). Across trials, increased amplitude and earlier latency were observed when beat gesture was temporally asynchronous with pitch accenting than when it was temporally synchronous with pitch accenting or absent. Moreover, temporal asynchrony of beat gesture relative to pitch accent increased trial-by-trial variability of N400 amplitude and latency and influenced the relationship between across-trial and trial-by-trial N400 latency. These results indicate that across-trial and trial-by-trial amplitude and latency of the N400 ERP reflect temporal integration of beat gesture and pitch accent during language comprehension, supporting extension of the integrated systems hypothesis of gesture-speech processing and neural noise theories to focus processing in typical adult populations.

Processing Ambiguous Morphemes in Chinese Compound Word Recognition: Behavioral and ERP Evidence

This study examined the processing of ambiguous morphemes in Chinese word recognition with a masked priming lexical decision task. Both behavioral and event-related potential (ERP) were recorded. All targets were bimorphemic compound words that contained ambiguous morphemes as the first morphemes. The ambiguous morphemes either took the dominant or subordinate interpretation, depending on the second morphemes. The prime words contained the same ambiguous morphemes in the dominant interpretation, the subordinate interpretation, or were unrelated to the targets. Analyses on response times revealed significant facilitative priming whenever primes and targets shared morphemes, but the strength of facilitation was stronger when the morpheme meanings were consistent. A similar pattern was found in the analyses of N400 (300–500 ms after target onset) amplitudes. However, in the earlier N250 time window (200–300 ms after target onset), only the dominant targets, but not the subordinate ones, were primed by the morpheme-sharing primes. More importantly, the strength of facilitation was similar between the dominant and subordinate primes. These results have two implications to the processing of ambiguous morphemes during Chinese compound word recognition. First, the morpheme meanings could be activated rapidly. Second, the more frequently used dominant meanings could be activated more easily than the less frequently used subordinate meanings.

Catecholaminergic Modulation of Semantic Processing in Sentence Comprehension.

Catecholamine (CA) function has been widely implicated in cognitive functions that are tied to the prefrontal cortex and striatal areas. The present study investigated the effects of methylphenidate, which is a CA agonist, on the electroencephalogram (EEG) response related to semantic processing using a double-blind, placebo-controlled, randomized, crossover, within-subject design. Forty-eight healthy participants read semantically congruent or incongruent sentences after receiving 20-mg methylphenidate or a placebo while their brain activity was monitored with EEG. To probe whether the catecholaminergic modulation is task-dependent, in one condition participants had to focus on comprehending the sentences, while in the other condition, they only had to attend to the font size of the sentence. The results demonstrate that methylphenidate has a task-dependent effect on semantic processing. Compared to placebo, when semantic processing was task-irrelevant, methylphenidate enhanced the detection of semantic incongruence as indexed by a larger N400 amplitude in the incongruent sentences; when semantic processing was task-relevant, methylphenidate induced a larger N400 amplitude in the semantically congruent condition, which was followed by a larger late positive complex effect. These results suggest that CA-related neurotransmitters influence language processing, possibly through the projections between the prefrontal cortex and the striatum, which contain many CA receptors.

The role of animacy in metaphor processing of Mandarin Chinese: An Event-Related Potential (ERP) study

Abstract Many ERP studies have highlighted processing difficulty for animacy violation in language, more so than non-violated sentences. However, all of these findings were for non-figurative language, and studies have rarely looked at the figurative language, such as metaphors involving animacy violation, which could be integrated to make novel and acceptable meaning. The present study aimed at assessing the role of animacy in metaphorical comprehension of Mandarin Chinese. ERPs were recorded as healthy participants read metaphor or literal sentences with animate or inanimate actors as sentence-initial noun, while the target words were measured at the verb and the second argument (object) of the sentences with subject-verb-object (SVO) structure. As expected, the animacy violations elicited a significant N400 effect by the target verb in the metaphor with inanimate initial-nouns. At the objects, the N400 amplitudes associated with metaphors were not regulated by animacy. Subsequently, the analysis revealed a significant difference in the P600 amplitudes between inanimate and animate metaphorical conditions. The metaphors with inanimate actor elicited an attenuated P600 as compared with the animate counterparts and converged to the same level as literal sentences, reflecting the less effortful metaphor-relevant mapping process. These results suggest that animacy violation may facilitate the integration of the reanalysis stage for metaphorical comprehension, and the conflict strength (animacy violation vs. no animacy violation) modulates the time course of metaphor processing in Mandarin Chinese. The present study yields new insights into the role of animacy in the online linguistic comprehension.

Engineering creativity: Prior experience modulates electrophysiological responses to novel metaphors

Novel metaphorical language use exemplifies human creativity through production and comprehension of meaningful linguistic expressions that may have never been heard before. Available electrophysiological research demonstrates, however, that novel metaphor comprehension is cognitively costly, as it requires integrating information from distantly related concepts. Herein, we investigate if such cognitive cost may be reduced as a factor of prior domain knowledge. To this end, we asked engineering and nonengineering students to read for comprehension literal, novel metaphorical, and anomalous sentences related to engineering or general knowledge, while undergoing EEG recording. Upon reading each sentence, participants were asked to judge whether or not the sentence was original in meaning (novelty judgment) and whether or not it made sense (sensicality judgment). When collapsed across groups, our findings demonstrate a gradual N400 modulation with N400 being maximal in response to anomalous, followed by metaphorical, and literal sentences. Between‐group comparisons revealed a mirror effect on the N400 to novel metaphorical sentences, with attenuated N400 in engineers and enhanced N400 in non‐engineers. Critically, planned comparisons demonstrated reduced N400 amplitudes to engineering novel metaphors in engineers relative to non‐engineers, pointing to an effect of prior knowledge on metaphor processing. This reduction, however, was observed in the absence of a sentence type × knowledge × group interaction. Altogether, our study provides novel evidence suggesting that prior domain knowledge may have a direct impact on creative language comprehension.

Neural correlates of processing Chinese structural particles: An ERP study

In order to investigate the neural correlates of processing Chinese structural particles, ‘De1 (的), De2 (地), and De3 (得)’, we recorded and analyzed the ERPs components related to the conflict processing in the judgement task, in which the participants are required to determine whether the target word matched the structural particle that appear in the given structure. We found that compared with the congruent condition, the frontal-central N400 and central-parietal P600 were elicited by the incongruent target word. Especially, three Chinese structural particles, ‘De1 (的), De2 (地), and De3 (得)’ modulated the amplitudes of N400 and P600 components and the incongruent condition of ‘De1’ elicited larger N400 and P600 than did ‘De2’ and ‘De3’, but no apparent difference appeared between the latter two structural particles. These data provide new electrophysiological evidence for processing Chinese structural particles.

Impairments in Probabilistic Prediction and Bayesian Learning Can Explain Reduced Neural Semantic Priming in Schizophrenia.

It has been proposed that abnormalities in probabilistic prediction and dynamic belief updating explain the multiple features of schizophrenia. Here, we used electroencephalography (EEG) to ask whether these abnormalities can account for the well-established reduction in semantic priming observed in schizophrenia under nonautomatic conditions. We isolated predictive contributions to the neural semantic priming effect by manipulating the prime's predictive validity and minimizing retroactive semantic matching mechanisms. We additionally examined the link between prediction and learning using a Bayesian model that probed dynamic belief updating as participants adapted to the increase in predictive validity. We found that patients were less likely than healthy controls to use the prime to predictively facilitate semantic processing on the target, resulting in a reduced N400 effect. Moreover, the trial-by-trial output of our Bayesian computational model explained between-group differences in trial-by-trial N400 amplitudes as participants transitioned from conditions of lower to higher predictive validity. These findings suggest that, compared with healthy controls, people with schizophrenia are less able to mobilize predictive mechanisms to facilitate processing at the earliest stages of accessing the meanings of incoming words. This deficit may be linked to a failure to adapt to changes in the broader environment. This reciprocal relationship between impairments in probabilistic prediction and Bayesian learning/adaptation may drive a vicious cycle that maintains cognitive disturbances in schizophrenia.

Predictors of chronicity in alcohol use disorder: an evoked response potential study

Introduction Evoked response potentials (ERP) can reliably map key neurocognitive processes which are putatively responsible for chronic alcohol use disorder (AUD). Aim of the present study was to study P300 auditory odd ball and N400 visual semantic incongruity paradigm mapping executive functions rubric as a potential biomarker predicting chronicity in AUDs. Methodology: 60 right handed 18 to 54 years age subjects were divided into chronic “CAD” and non chronic alcohol dependence “NAD” in addition to healthy control “HC” (N = 30). Subjects were assessed by Addiction Severity Index (ASI), P300 auditory odd ball paradigm in midline region and visual N400 semantic incongruity task in centro-parietal region in a cross sectional design. Results: All the three groups differed significantly for P300 and N400 amplitude in all the leads with maximum attenuation seen in CAD. On discriminant function analysis (DFA), P300 Pz and N 400 C2 amplitude values could accurately classified 78.3% subjects. Composite sensitivity and specificity of the two predictor variables differentiating CAD subjects from NAD were 79.31 and 77.41%. receiver operating characteristic curve generated an area under the curve of .758 and .847 i.e., “fair to good” ability to predict CAD from NAD. Conclusion: We conclude that specific ERP paradigm can be used as a state marker to map the cognitive deficits and as a biomarker to detect chronic AUDs.

Gesture style can affect the integration of gestures and speech: the evidence from Chinese ERP research.

People often accompany gestures in the process of speaking, but the individual's gesture style is not the same. The present study uses the ambiguity resolution paradigm to explore the influence of two kinds of gesture styles on gesture-verbal comprehension. The study manipulated the gesture styles and meaning types of target words and recorded N400 amplitude. This study found that (1) in the non-grooming condition, compared with the situation where the gesture and semantics are inconsistent, a smaller N400 appears under the consistent condition; (2) in the grooming condition, the grooming gesture will reduce the effect of the iconic gesture on speech understanding. N400 amplitude increased only in the case of matching between dominant meaning gesture and subordinate meaning target word. These results suggest that the communication styles of gestures of different speakers, in the process of speech comprehension, affect how well listeners integrate gestures and language.

Neurocognitive Correlates of Statistical Learning of Orthographic-Semantic Connections in Chinese Adult Learners.

We examined the neural correlates of the statistical learning of orthographic-semantic connections in Chinese adult learners. Visual event-related potentials (ERPs) were recorded while participants were exposed to a sequence of artificial logographic characters containing semantic radicals carrying low, moderate, or high levels of semantic consistency. The behavioral results showed that the mean accuracy of participants' recognition of previously exposed characters was 63.1% that was significantly above chance level (50%), indicating the statistical learning of the regularities of semantic radicals. The ERP data revealed a temporal sequence of the neural process of statistical learning of orthographic-semantic connections, and different brain indexes were found to be associated with this processing, i.e., a clear N170-P200-N400 pattern. For N170, the larger negative amplitudes were evoked by the high and moderate consistency than the low consistency. For P200, the mean amplitudes elicited by the moderate and low consistency were larger than the high consistency. In contrast, a larger N400 amplitude was observed in the low than moderate and high consistency; and more negative amplitude was elicited by the moderate than high consistency. We propose that the initial potential shifts (N170 and P200) may reflect orthographic or graphic form identification, while the later component (N400) may be associated with semantic information analysis.

Here's looking at you, kid? Maternal depression and adolescent attention to self- or other-directed emotional faces

BackgroundMaternal depression history represents a significant risk factor for developing psychopathology in children, altered emotional responding may represent a central risk pathway. However, additional research is needed on factors that affect the strength or direction of response alterations in relation to depression-risk in youth. In particular, facial orientation and gaze direction may alter personal relevance, with emotions directed towards an individual heightening motivational salience, compared to emotions directed away. MethodsMother-daughter dyads (N = 56) were recruited based on presence or absence of maternal depression history and absence of youth depression. In line with theoretical perspectives suggesting diminished sensitivity to emotional context in relation to depression risk, we examined three Event-Related Potential (ERP) components in relation to forward versus averted emotional faces in a sample of girls with and without a maternal history of depression: the N200, N400, and Late Positive Potential (LPP). ResultsResults showed a significant maternal depression history by face-orientation effect. Low-risk girls exhibited more negative N200 and N400 amplitudes for straight (M = −3.72, SE = 0.83; M = −3.57, SE = 0.86) versus averted (M = −2.15, SE = 0.76; M = −1.68, SE = 0.81) faces, while girls of mothers with histories of depression showed undifferentiated N200 or N400 responses in relation to face orientation. For LPP amplitudes, low-risk girls exhibited significantly more positive LPP amplitudes than high-risk girls, but only for averted faces (M = 0.69, SE = 0.59 and M = −2.63, SE = 0.74, respectively). LimitationsCross-sectional design and limited sample. ConclusionsResults indicate that familial depression risk is associated with altered responsivity to face-orientation, these were interpreted as representing differential sensitivity to the personal-relevance of emotional stimuli.

Change in a probabilistic representation of meaning can account for N400 effects on articles: A neural network model

Increased N400 amplitudes on indefinite articles (a/an) incompatible with expected nouns have been initially taken as strong evidence for probabilistic pre-activation of phonological word forms, and recently been intensely debated because they have been difficult to replicate. Here, these effects are simulated using a neural network model of sentence comprehension that we previously used to simulate a broad range of empirical N400 effects. The model produces the effects when the cue validity of the articles concerning upcoming noun meaning in the learning environment is high, but fails to produce the effects when the cue validity of the articles is low due to adjectives presented between articles and nouns during training. These simulations provide insight into one of the factors potentially contributing to the small size of the effects in empirical studies and generate predictions for cross-linguistic differences in article induced N400 effects based on articles’ cue validity. The model accounts for article induced N400 effects without assuming pre-activation of word forms, and instead simulates these effects as the stimulus-induced change in a probabilistic representation of meaning corresponding to an implicit semantic prediction error.

Religiosity is associated with less prediction of the typical: An event-related brain potential study

Why are some people more religious than others? According to one hypothesis, people who strongly seek definitive explanations for situations with incomplete information are more likely to be religious. According to a different hypothesis, individuals with smaller “prediction error” responses to unexpected stimuli are more likely to discount evidence contradicting religious beliefs, predisposing them to maintain such beliefs. We sought neurophysiological evidence for these hypotheses using the N400 event-related potential (ERP), which is smaller to more contextually expected stimuli, reflecting prediction of probable completions for meaningful situations. We recorded ERPs from participants viewing category definitions followed by high-typicality category exemplar (HTE), low-typicality exemplar (LTE), or non-exemplar (NE) words. As expected, N400s were largest for NEs, intermediate for LTEs, and smallest for HTEs. Religiosity correlated with smaller N400 amplitude differences between HTEs and both LTEs and NEs. Less strong prediction of probable stimuli based on prior information may predispose to religiosity.