A developmental ERP study of verbal and non-verbal semantic processing

Effects of childhood institutionalization on semantic processing and its neural correlates persist into adolescence and adulthood

Individuals raised in institutionalized care settings are more likely to demonstrate developmental deficits than those raised in biological families. One domain that is vulnerable to the impoverished environments characteristic of some institutionalized care facilities is language development. We used EEG to assess ERPs and source-localized event-related spectral perturbations (ERSPs) associated with semantic processing at different levels of picture-word conflict and low versus high word frequency. Additionally, we assessed behavioral language ability (a synonyms task) and IQ. Participants (N = 454) were adolescents and adults with a history of institutionalized care (N = 187) or raised in biological families (N = 267), both recruited from secondary educational settings to approximately match the groups on age and education. Results indicate that individuals with a history of institutionalization are less accurate at judging whether semantic information in a spoken word matches an image. Additionally, those with a history of institutionalization show reduced cognitive control of conflict and more reactive N400 ERPs and beta ERSPs when handling picture-word conflict, especially in the left hemisphere. Frontal theta is related to semantic and conflict processing; however, in this study it did not vary with institutionalization.

Auditory dominance in processing Chinese semantic abnormalities in response to competing audio-visual stimuli

Language is a remarkable cognitive ability that can be expressed through visual (written language) or auditory (spoken language) modalities. When visual characters and auditory speech convey conflicting information, individuals may selectively attend to either one of them. However, the dominant modality in such a competing situation and the neural mechanism underlying it are still unclear. Here, we presented participants with Chinese sentences in which the visual characters and auditory speech convey conflicting information, while behavioral and electroencephalographic (EEG) responses were recorded. Results showed a prominent auditory dominance when audio-visual competition occurred. Specifically, higher accuracy (ACC), larger N400 amplitudes and more linkages in the posterior occipital-parietal areas were demonstrated in the auditory mismatch condition compared to that in the visual mismatch condition. O0ur research illustrates the superiority of the auditory speech over the visual characters, extending our understanding of the neural mechanisms of audio-visual competition in Chinese.

Age-related differences in expectation-based novel word learning

Adult language users can infer the meaning of a previously unfamiliar word from a single exposure to this word in a semantically and thematically constrained context, henceforth, predictive context (Borovsky et al., 2010 Cognition, 116(2), 289-296; Borovsky et al., 2012 Language Learning and Development, 8(3), 278-302). Children use predictive contexts to anticipate upcoming stimuli (Borovsky et al., 2012 Language Learning and Development, 8(3), 278-302; Mani & Huettig, 2012 Journal of Experimental Psychology: Human Perception and Performance, 38(4), 843-847), but the extent to which they rely on prediction to learn novel word forms is unclear (Gambi et al., 2021 Cognition, 211, 104650). Here, we examine children's one-shot learning from predictive contexts using a modified version of the one-shot learning ERP paradigm for children aged 7-13 years. In a first learning phase, we presented audio recordings of expected words and unexpected novel pseudowords in strongly and weakly constraining sentence contexts. In the following priming phase, the same recorded words and pseudowords were used as primes to identical/synonymous, related, and unrelated target words. We measured N400 modulations to the word and pseudoword continuations in the learning phase and to the identical/synonymous, related, or unrelated target words in the priming phase. When initially presented in strongly constraining sentences, novel pseudowords primed synonymous targets equally well as word primes of the same intended meaning. This pattern was particularly pronounced in older children. Our findings suggest that, around early adolescence, children can use single exposures to constraining contexts to infer the meaning of novel words and to integrate these novel words in their lexicons.

Learning Words While Listening to Syllables: Electrophysiological Correlates of Statistical Learning in Children and Adults

From an early age, exposure to a spoken language has allowed us to implicitly capture the structure underlying the succession of speech sounds in that language and to segment it into meaningful units (words). Statistical learning (SL), the ability to pick up patterns in the sensory environment without intention or reinforcement, is thus assumed to play a central role in the acquisition of the rule-governed aspects of language, including the discovery of word boundaries in the continuous acoustic stream. Although extensive evidence has been gathered from artificial languages experiments showing that children and adults are able to track the regularities embedded in the auditory input, as the probability of one syllable to follow another syllable in the speech stream, the developmental trajectory of this ability remains controversial. In this work, we have collected Event-Related Potentials (ERPs) while 5-year-old children and young adults (university students) were exposed to a speech stream made of the repetition of eight three-syllable nonsense words presenting different levels of predictability (high vs. low) to mimic closely what occurs in natural languages and to get new insights into the changes that the mechanisms underlying auditory statistical learning (aSL) might undergo through the development. The participants performed the aSL task first under implicit and, subsequently, under explicit conditions to further analyze if children take advantage of previous knowledge of the to-be-learned regularities to enhance SL, as observed with the adult participants. These findings would also contribute to extend our knowledge of the mechanisms available to assist SL at each developmental stage. Although behavioral signs of learning, even under explicit conditions, were only observed for the adult participants, ERP data showed evidence of online segmentation in the brain in both groups, as indexed by modulations in the N100 and N400 components. A detailed analysis of the neural data suggests, however, that adults and children rely on different mechanisms to assist the extraction of word-like units from the continuous speech stream, hence supporting the view that SL with auditory linguistic materials changes through development.

Neural correlates of sex differences in communicative gestures and speech comprehension: A preliminary study

The goal of this study was to investigate whether the semantic processing of the audiovisual combination of communicative gestures with speech differs between men and women. We recorded event-related brain potentials in women and men during the presentation of communicative gestures that were either congruent or incongruent with the speech.Our results showed that incongruent gestures elicited an N400 effect over frontal sites compared to congruent ones in both groups. Moreover, the females showed an earlier N2 response to incongruent stimuli than congruent ones, while larger sustained negativity and late positivity in response to incongruent stimuli was observed only in males. These results suggest that women rapidly recognize and process audiovisual combinations of communicative gestures and speech (as early as 300 ms) whereas men analyze them at the later stages of the process.

Differences in adverse drug events and medication errors among pediatric inpatients aged <3 and ≥3 years: The JADE study

Background

Adverse drug events (ADEs) are defined as any injuries due to medication use. We hypothesized that the incidences of ADEs and medication errors (MEs) could be associated with linguistic skills of pediatric patients.

Methods

We analyzed data from the Japan Adverse Drug Events study on pediatric inpatients. This study included inpatients aged one months and older and less than seven years old. We compared the primary outcome of ADEs and MEs between patients aged under three years and three years and older as children typically do not acquire sufficient linguistic skills until around three years of age.

Results

This study included 639 patients; 412 (64%) patients aged under three years and 227 (36%) patients aged three years and older. We identified 241 ADEs in 639 patients; 152 ADEs among patients aged under three years (37 ADEs per 100 patients) and 89 ADEs among those aged three years and older (39 ADEs per 100 patients). ADEs among patients aged under three years were less likely to be found (49 ADEs) during their hospital stay than those aged three years and older (20 ADEs) ( P = 0.02). Among 172 MEs identified in 639 patients, 25 MEs (15%) resulted in ADEs; 23 (92%) occurred to those aged under three years and two (8%) occurred to those aged three years and older ( P = 0.0008).

Conclusion

ADEs were less likely to be found and MEs resulted in ADEs more frequently in patients under three years old, and these differences could be explained by differences in their linguistic skill levels.

Crossmodal processing of environmental sounds and everyday life actions: An ERP study

To investigate the processing of environmental sounds, previous researchers have compared the semantic processing of words and sounds, yielding mixed results. This study aimed to specifically investigate the electrophysiological mechanism underlying the semantic processing of environmental sounds presented in a naturalistic visual scene. We recorded event-related brain potentials in a group of young adults over the presentation of everyday life actions that were either congruent or incongruent with environmental sounds. Our results showed that incongruent environmental sounds evoked both a P400 and an N400 effect, reflecting sensitivity to physical and semantic violations of environmental sounds’ properties, respectively. In addition, our findings showed an enhanced late positivity in response to incongruous environmental sounds, probably reflecting additional reanalysis costs. In conclusion, these results indicate that the crossmodal processing of the environmental sounds might require the simultaneous involvement of different cognitive processes.

Inhibition Effect of Audio-Visual Semantic Interference in Chinese Interface: An ERP Study of Concrete Icons and Chinese Characters

In this study, event-related potential (ERP) was used to examine whether the brain has an inhibition effect on the interference of audio-visual information in the Chinese interface. Concrete icons (flame and snowflake) or Chinese characters (暖 and 凉) with opposite semantics were used as target carriers, and colors (red and blue) and speeches (热 and 冷) were used as audio-visual intervention stimuli. In the experiment, target carrier and audio-visual intervention were presented in a random combination, and the subjects needed to determine whether the semantics of the two matched quickly. By comparing the overall cognitive performance of two carriers, it was found that the brain had a more significant inhibition effect on audio-visual intervention stimuli with different semantics (SBH/LBH and SRC/LRC) relative to the same semantics (SRH/LRH). The semantic mismatch caused significant N400, indicating that semantic interference in the interface information would trigger the brain’s inhibition effect. Therefore, the more complex the semantic matching of interface information was, the higher the amplitude of N400 became. The results confirmed that the semantic relationship between target carrier and audio-visual intervention was the key factor affecting the cognitive inhibition effect. Moreover, under different intervention stimuli, the ERP’s negative activity caused by Chinese characters in frontal and parietal-occipital regions was more evident than that by concrete icons, indicating that concrete icons had a lower inhibition effect than Chinese characters. Therefore, we considered that this inhibition effect was based on the semantic constraints of the target carrier itself, which might come from the knowledge learning and intuitive experience stored in the human brain.

The electrophysiology of audiovisual processing in visual narratives in adolescents with autism spectrum disorder

We investigated the semantic processing of the multimodal audiovisual combination of visual narratives with auditory descriptive words and auditory sounds in individuals with ASD. To this aim, we recorded ERPs to critical auditory words and sounds associated with events in visual narrative that were either semantically congruent or incongruent with the climactic visual event. A similar N400 effect was found both in adolescents with ASD and neurotypical adolescents (ages 9-16) when accessing different types of auditory information (i.e. words and sounds) into a visual narrative. This result might suggest that verbal information processing in ASD adolescents could be facilitated by direct association with meaningful visual information. In addition, we observed differences in scalp distribution of later brain responses between ASD and neurotypical adolescents. This finding might suggest ASD adolescents differ from neurotypical adolescents during the processing of the multimodal combination of visual narratives with auditory information at later stages of the process. In conclusion, the semantic processing of verbal information, typically impaired in individuals with ASD, can be facilitated when embedded into a meaningful visual information.

Sentence contexts and cloze probabilities for Brazilian Portuguese children and adolescents

PURPOSE

In this study we investigated a set of 100 sentence contexts and their cloze probabilities to develop a database of linguistic stimuli for Brazilian Portuguese children and adolescents. The study also examined age-related changes on cloze probabilities, and specified the predictor effects of age and cloze probabilities on idiosyncratic responses and errors (semantic, syntactic, and other errors). Finally, the study also aimed to shed light on cultural effects on word generation by comparing Brazilian and Portuguese sentence databases.

METHOD

361 typically developing monolingual Brazilian speakers, with ages ranging from 7 to 18 years, participated in the study. The cloze task was composed by 100 sentence contexts, grounded on the European Portuguese database. Responses were classified as valid (correct) or invalid (semantic, syntactic, and other-type errors). Statistical analyses were based on mixed-effects logistic models.

RESULTS

Sixty-three sentences met criteria for high cloze probabilities, 30 for medium cloze, and 7 for low cloze. Age was a significant predictor of idiosyncratic responses, semantic and syntactic errors: older participants were less likely to produce idiosyncratic responses, as well as semantic and syntactic errors. Cloze probability values were concordant in the Brazilian and Portuguese databases for 31 out of 49 (83.7%) high-cloze sentences and for 7 low-cloze sentences.

CONCLUSION

In this study we have provided a database with cloze probability values for a set of 100 sentence-final word contexts for Brazilian Portuguese children and adolescents. Results showed that both age and sentence contextual level predicted sentence final word completion. Older participants were more likely to choose more consistently the same final word, with the contextual level of a given sentence also contributing to the final word selection. Age should be controlled for in future studies probing semantic processing with this set of sentences.

Changes in event-related brain responses and habituation during child development - A systematic literature review

OBJECTIVE

This systematic review highlights the influence of developmental changes of the central nervous system on habituation assessment during child development. Therefore, studies on age dependant changes in event-related brain responses as well as studies on behavioural and neurophysiological habituation during child development are compiled and discussed.

METHODS

Two PubMed searches with terms "(development evoked brain response (fetus OR neonate OR children) (electroencephalography OR magnetoencephalography))" and with terms "(psychology habituation (fetal OR neonate OR children) (human brain))" were performed to identify studies on developmental changes in event-related brain responses as well as habituation studies during child development.

RESULTS

Both search results showed a wide diversity of subjects' ages, stimulation protocols and examined behaviour or components of event-related brain responses as well as a demand for more longitudinal study designs.

CONCLUSIONS

A conclusive statement about clear developmental trends in event-related brain responses or in neurophysiological habituation studies is difficult to draw. Future studies should implement longitudinal designs, combination of behavioural and neurophysiological habituation measurement and more complex habituation paradigms to assess several habituation criteria.

SIGNIFICANCE

This review emphasizes that event-related brain responses underlie certain changes during child development which should be more considered in the context of neurophysiological habituation studies.

The organization of words and environmental sounds in the second year: Behavioral and electrophysiological evidence

The majority of research examining early auditory-semantic processing and organization is based on studies of meaningful relations between words and referents. However, a thorough investigation into the fundamental relation between acoustic signals and meaning requires an understanding of how meaning is associated with both lexical and non-lexical sounds. Indeed, it is unknown how meaningful auditory information that is not lexical (e.g., environmental sounds) is processed and organized in the young brain. To capture the structure of semantic organization for words and environmental sounds, we record event-related potentials as 20-month-olds view images of common nouns (e.g., dog) while hearing words or environmental sounds that match the picture (e.g., "dog" or barking), that are within-category violations (e.g., "cat" or meowing), or that are between-category violations (e.g., "pen" or scribbling). Results show both words and environmental sounds exhibit larger negative amplitudes to between-category violations relative to matches. Unlike words, which show a greater negative response early and consistently to within-category violations, such an effect for environmental sounds occurs late in semantic processing. Thus, as in adults, the young brain represents semantic relations between words and between environmental sounds, though it more readily differentiates semantically similar words compared to environmental sounds.

Listening beyond seeing: Event-related potentials to audiovisual processing in visual narrative

Every day we integrate meaningful information coming from different sensory modalities, and previous work has debated whether conceptual knowledge is represented in modality-specific neural stores specialized for specific types of information, and/or in an amodal, shared system. In the current study, we investigated semantic processing through a cross-modal paradigm which asked whether auditory semantic processing could be modulated by the constraints of context built up across a meaningful visual narrative sequence. We recorded event-related brain potentials (ERPs) to auditory words and sounds associated to events in visual narratives-i.e., seeing images of someone spitting while hearing either a word (Spitting!) or a sound (the sound of spitting)-which were either semantically congruent or incongruent with the climactic visual event. Our results showed that both incongruent sounds and words evoked an N400 effect, however, the distribution of the N400 effect to words (centro-parietal) differed from that of sounds (frontal). In addition, words had an earlier latency N400 than sounds. Despite these differences, a sustained late frontal negativity followed the N400s and did not differ between modalities. These results support the idea that semantic memory balances a distributed cortical network accessible from multiple modalities, yet also engages amodal processing insensitive to specific modalities.

"I know something you don't know": Discourse and social context effects on the N400 in adolescents

Adolescence is a time of great cognitive and social development. Despite this, relatively few studies to date have investigated how perspective taking affects on-line language comprehension in adolescents. In the current study, we addressed this gap in the literature, making use of a Joint Comprehension Task in which two individuals with differing background knowledge jointly attend to linguistic stimuli. Using event-related potentials, we investigated adolescents' electrophysiological responses to (a) semantically anomalous sentence stimuli in discourse context and (b) semantically plausible sentence stimuli that the participants believe another individual finds semantically implausible. Our results demonstrate that a robust "N400 effect" (i.e., a well-established event-related potential, known to be sensitive to lexical-semantic integration difficulties)  is elicited by semantically anomalous sentences; this N400 effect is subsequently attenuated by discourse context. Lastly, a "social N400 effect" is elicited by sentences that are semantically plausible for the participants if they believe that another individual finds the sentences implausible. The results suggest that adolescents integrate the perspective of others during on-line language comprehension via simulation; that is, adolescents use their own language processing system to interpret language input from the perspective of other jointly attending individuals.

When a hit sounds like a kiss: An electrophysiological exploration of semantic processing in visual narrative

Researchers have long questioned whether information presented through different sensory modalities involves distinct or shared semantic systems. We investigated uni-sensory cross-modal processing by recording event-related brain potentials to words replacing the climactic event in a visual narrative sequence (comics). We compared Onomatopoeic words, which phonetically imitate action sounds (Pow!), with Descriptive words, which describe an action (Punch!), that were (in)congruent within their sequence contexts. Across two experiments, larger N400s appeared to Anomalous Onomatopoeic or Descriptive critical panels than to their congruent counterparts, reflecting a difficulty in semantic access/retrieval. Also, Descriptive words evinced a greater late frontal positivity compared to Onomatopoetic words, suggesting that, though plausible, they may be less predictable/expected in visual narratives. Our results indicate that uni-sensory cross-model integration of word/letter-symbol strings within visual narratives elicit ERP patterns typically observed for written sentence processing, thereby suggesting the engagement of similar domain-independent integration/interpretation mechanisms.

Explicit and Implicit Verbal Response Inhibition in Preschool-Age Children Who Stutter

PURPOSE

The purpose of this study was to examine (a) explicit and implicit verbal response inhibition in preschool children who do stutter (CWS) and do not stutter (CWNS) and (b) the relationship between response inhibition and language skills.

METHOD

Participants were 41 CWS and 41 CWNS between the ages of 3;1 and 6;1 (years;months). Explicit verbal response inhibition was measured using a computerized version of the grass-snow task (Carlson & Moses, 2001), and implicit verbal response inhibition was measured using the baa-meow task. Main dependent variables were reaction time and accuracy.

RESULTS

The CWS were significantly less accurate than the CWNS on the implicit task, but not the explicit task. The CWS also exhibited slower reaction times than the CWNS on both tasks. Between-group differences in performance could not be attributed to working memory demands. Overall, children's performance on the inhibition tasks corresponded with parents' perceptions of their children's inhibition skills in daily life.

CONCLUSIONS

CWS are less effective and efficient than CWNS in suppressing a dominant response while executing a conflicting response in the verbal domain.

Influence of auditory spatial attention on cross-modal semantic priming effect: evidence from N400 effect

Semantic priming is an important research topic in the field of cognitive neuroscience. Previous studies have shown that the uni-modal semantic priming effect can be modulated by attention. However, the influence of attention on cross-modal semantic priming is unclear. To investigate this issue, the present study combined a cross-modal semantic priming paradigm with an auditory spatial attention paradigm, presenting the visual pictures as the prime stimuli and the semantically related or unrelated sounds as the target stimuli. Event-related potentials results showed that when the target sound was attended to, the N400 effect was evoked. The N400 effect was also observed when the target sound was not attended to, demonstrating that the cross-modal semantic priming effect persists even though the target stimulus is not focused on. Further analyses revealed that the N400 effect evoked by the unattended sound was significantly lower than the effect evoked by the attended sound. This contrast provides new evidence that the cross-modal semantic priming effect can be modulated by attention.

From Sensory Perception to Lexical-Semantic Processing: An ERP Study in Non-Verbal Children with Autism

This study examines electrocortical activity associated with visual and auditory sensory perception and lexical-semantic processing in nonverbal (NV) or minimally-verbal (MV) children with Autism Spectrum Disorder (ASD). Currently, there is no agreement on whether these children comprehend incoming linguistic information and whether their perception is comparable to that of typically developing children. Event-related potentials (ERPs) of 10 NV/MV children with ASD and 10 neurotypical children were recorded during a picture-word matching paradigm. Atypical ERP responses were evident at all levels of processing in children with ASD. Basic perceptual processing was delayed in both visual and auditory domains but overall was similar in amplitude to typically-developing children. However, significant differences between groups were found at the lexical-semantic level, suggesting more atypical higher-order processes. The results suggest that although basic perception is relatively preserved in NV/MV children with ASD, higher levels of processing, including lexical- semantic functions, are impaired. The use of passive ERP paradigms that do not require active participant response shows significant potential for assessment of non-compliant populations such as NV/MV children with ASD.

The organization of words and environmental sounds in memory

In the present study we used event-related potentials to compare the organization of linguistic and meaningful nonlinguistic sounds in memory. We examined N400 amplitudes as adults viewed pictures presented with words or environmental sounds that matched the picture (Match), that shared semantic features with the expected match (Near Violation), and that shared relatively few semantic features with the expected match (Far Violation). Words demonstrated incremental N400 amplitudes based on featural similarity from 300-700ms, such that both Near and Far Violations exhibited significant N400 effects, however Far Violations exhibited greater N400 effects than Near Violations. For environmental sounds, Far Violations but not Near Violations elicited significant N400 effects, in both early (300-400ms) and late (500-700ms) time windows, though a graded pattern similar to that of words was seen in the mid-latency time window (400-500ms). These results indicate that the organization of words and environmental sounds in memory is differentially influenced by featural similarity, with a consistently fine-grained graded structure for words but not sounds.

Environmental sound recognition by timbre in children with Williams syndrome

Anecdotal reports have described children with Williams syndrome (WS) as presenting outstanding skills for recognizing environmental sounds by their timbre. This has led to suggest that the skills for environmental sound recognition by timbre are highly developed in WS. Furthermore, the term hypertimbria has been proposed to refer to this feature. However, no academic research has assessed these skills in WS. This study therefore aimed to contrast the reports on the highly developed skills for environmental sound recognition by timbre in children with WS. An environmental sound recognition task was administered to children with WS, children with Down syndrome of the same chronological age and cognitive level, and chronological age-matched typically developing children. Participants with WS performed significantly lower than their typically developing peers and no significant differences were found between the WS and Down syndrome groups. Unlike previous reports, this study points out that in WS environmental sound recognition by timbre does not constitute a phenotypic strength either in absolute or relative terms. Results suggest that children with WS do not present hypertimbria or preserved skills for timbre recognition. We discuss the implications of these results for theories of cognitive modularity.

Event-related potentials to intact and disrupted actions in children and adults

The current research used event-related potentials (ERPs) to investigate neurophysiological responses to intact and disrupted actions embedded within an event in children and adults. Responses were recorded as children (24-month-olds) and adults observed a relatively novel event composed of three actions. In one condition pauses were inserted at intact boundaries (i.e., at the endpoint of each action), whereas in the other condition they were inserted at breakpoints that disrupted the action (i.e., in the middle of each action). Evoked responses revealed differences across conditions in both groups; disrupted actions elicited a prolonged negative slow wave from 100 to 700 ms in children, whereas adults demonstrated two distinct negative peaks between 50-150 and 250-350 ms. These findings contribute the first electrophysiological evidence that children readily detect disruptions to ongoing events by the end of the second year, even with limited exposure to the event itself. Furthermore, they suggest that adults rely on two distinct mechanisms when processing novel events. Results are discussed in relation to the role of perceptual and conceptual levels of analysis in the development of action processing.

Intact language skills and semantic processing speed following the use of fractionated cranial irradiation therapy for the treatment of childhood medulloblastoma: a 4-year follow-up study

Recent advances in the delivery of cranial radiation therapy aim to reduce the adverse neurocognitive outcomes associated with successful treatments. Damage to white matter tracts following cranial radiation may result in a reduction in information processing speed, which in turn may lead to declines in academic achievement and performance scores on neurocognitive testing. This study reports on language outcomes and neurophysiological measures reflecting the efficiency of the brain's capacity to process semantic information in a 14-year-old female following treatment, which included fractionated cranial radiation dosages, for medulloblastoma at age 10 years 3 months. The findings suggest processing skills on par with her peers and stability in general language skill over the 4 years post-treatment.

Semantic association of ecologically unrelated synchronous audio-visual information in cognitive integration: an event-related potential study

In this paper, we aimed to study the semantic association of ecologically unrelated synchronous audio-visual information in cognitive integration. A moving particle, which speed varied, was taken as a visual stimulus, while a simple tone, which frequency varied, was used as an auditory stimulus, both were synchronously presented to subjects in the form of a video. Behavioral results confirmed our hypothesis that the moving particle with varied speed and the simple tone with varied frequency were highly associated. Event-related potential (ERP) results showed that an N400 effect and a late posterior negativity (LPN) were elicited under the Incongruent condition as compared to the Congruent condition. It was further determined that there was semantic association between ecologically unrelated synchronous audio-visual information in cognitive integration. We considered that the N400 effect in our results reflected the process that stimulus-driven activities are bound together through a temporal semantic network (TSN) to form multimodal representations, while the state of this temporal semantic network was determined by both long-term learned association among stimuli and short-term experience of incoming information. The LPN might reflect the process that the human brain searches and retrieves context-specifying information in order to make a judgment, and the context-specifying information might have originated from the long-term learned association stored in the brain.

Semantic processing in children and adults: incongruity and the N400

Semantic processing in 10-year-old children and adults was examined using event related potentials (ERPs). The N400 component, an index of semantic processing, was studied in relation to sentences that ended with congruent, moderately incongruent, or strongly incongruent words. N400 amplitude in adults corresponded to levels of semantic incongruity with the greatest amplitude occurring to strongly incongruent sentences at all midline electrodes. In contrast, children's N400s were greater for both moderately and strongly incongruent sentences but did not differ between these levels of incongruity. This finding suggests that semantic processing may differ in adults and children.

Electrophysiological correlates of semantic processing in Williams syndrome

Williams syndrome (WS), a genetic neurodevelopmental disorder due to microdeletion in chromosome 7, has been described as a syndrome with an intriguing socio-cognitive phenotype. Cognitively, the relative preservation of language and face processing abilities coexists with severe deficits in visual-spatial tasks, as well as in tasks involving abstract reasoning. However, in spite of early claims of the independence of language from general cognition in WS, a detailed investigation of language subcomponents has demonstrated several abnormalities in lexical-semantic processing. Nonetheless, the neurobiological processes underlying language processing in Williams syndrome remain to be clarified. The aim of this study was to examine the electrophysiological correlates of semantic processing in WS, taking typical development as a reference. A group of 12 individuals diagnosed with Williams syndrome, with age range between 9 and 31 years, was compared with a group of typically developing participants, individually matched in chronological age, gender and handedness. Participants were presented with sentences that ended with words incongruent (50%) with the previous sentence context or with words judged to be its best completion (50%), and they were asked to decide if the sentence made sense or not. Results in WS suggest atypical sensory ERP components (N100 and P200), preserved N400 amplitude, and abnormal P600 in WS, with the latter being related to late integration and re-analysis processes. These results may represent a physiological signature of underlying impaired on-line language processing in this disorder.

Neural correlates of verbal and nonverbal semantic integration in children with autism spectrum disorders

BACKGROUND

Autism is a pervasive developmental disorder characterized by deficits in social-emotional, social-communicative, and language skills. Behavioral and neuroimaging studies have found that children with autism spectrum disorders (ASD) evidence abnormalities in semantic processing, with particular difficulties in verbal comprehension. However, it is not known whether these semantic deficits are confined to the verbal domain or represent a more general problem with semantic processing. The focus of the current study was to investigate verbal and meaningful nonverbal semantic processing in high-functioning children with autism (mean age = 5.8 years) using event-related potentials (ERPs).

METHOD

ERPs were recorded while children attended to semantically matching and mismatching picture-word and picture-environmental sound pairs.

RESULTS

ERPs of typically developing children exhibited evidence of semantic incongruency detection in both the word and environmental sound conditions, as indexed by elicitation of an N400 effect. In contrast, children with ASD showed an N400 effect in the environmental sound condition but not in the word condition.

CONCLUSIONS

These results provide evidence for a deficiency in the automatic activation of semantic representations in children with ASD, and suggest that this deficit is somewhat more selective to, or more severe in, the verbal than the nonverbal domain.

Verbal and nonverbal semantic processing in children with developmental language impairment

In an effort to clarify whether semantic integration is impaired in verbal and nonverbal auditory domains in children with developmental language impairment (a.k.a., LI and SLI), the present study obtained behavioral and neural responses to words and environmental sounds in children with language impairment and their typically developing age-matched controls (ages 7-15 years). Event-related brain potentials (ERPs) were recorded while children performed a forced-choice matching task on semantically matching and mismatching visual-auditory, picture-word and picture-environmental sound pairs. Behavioral accuracy and reaction time measures were similar for both groups of children, with environmental sounds eliciting more accurate responses than words. In picture-environmental sound trials, behavioral performance and the brain's response to semantic incongruency (i.e., the N400 effect) of the children with language impairment were comparable to those of their typically developing peers. However, in picture-word trials, children with LI tended to be less accurate than their controls and their N400 effect was significantly delayed in latency. Thus, the children with LI demonstrated a semantic integration deficit that was somewhat specific to the verbal domain. The particular finding of a delayed N400 effect is consistent with the storage deficit hypothesis of language impairment (Kail & Leonard, 1986) suggesting weakened and/or less efficient connections within the language networks of children with LI.

Infants' recognition of meaningful verbal and nonverbal sounds

To examine how young children recognize the association between two different types of meaningful sounds and their visual referents, we compared 15-, 20-, and 25-month-old infants' looking time responses to familiar naturalistic environmental sounds, (e.g., the sound of a dog barking) and their empirically matched verbal descriptions (e.g., "Dog barking") in an intermodal preferential looking paradigm. Across all three age groups, performance was indistinguishable over the two domains. Infants with the largest vocabularies were more accurate in processing the verbal phrases than the environmental sounds. However, after taking into account each child's verbal comprehension/production and the onomatopoetic test items, all cross-domain differences disappeared. Correlational analyses revealed that the processing of environmental sounds was tied to chronological age, while the processing of speech was linked to verbal proficiency. Overall, while infants' ability to recognize the two types of sounds did not differ behaviorally, the underlying processes may differ depending on the type of auditory input.

The development of semantic priming effect in childhood: an event-related potential study

To investigate the development of semantic priming effect in school children, we examined the event-related potentials in 120 children from 7 to 12 years when they were instructed to perform a lexical decision task. The well-known N400 component and a late positive component showed parabolic changes with the age growing. In addition, the lateralization of the brain potentials indicated the early stage in elementary school was the curial time for development of linguistic neural networks. This finding first revealed the detailed changes of semantic priming effect in childhood.