Late Positive Shift Research Articles

Neurophysiological basis of the N400 deflection, from Mismatch Negativity to Semantic Prediction Potentials and late positive components

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

Cross-modal integration of polyphonic characters in Chinese audio-visual sentences: a MVPA study based on functional connectivity.

This study aimed to investigate the functional connectivity in the brain during the cross-modal integration of polyphonic characters in Chinese audio-visual sentences. The visual sentences were all semantically reasonable and the audible pronunciations of the polyphonic characters in corresponding sentences contexts varied in four conditions. To measure the functional connectivity, correlation, coherence and phase synchronization index (PSI) were used, and then multivariate pattern analysis was performed to detect the consensus functional connectivity patterns. These analyses were confined in the time windows of three event-related potential components of P200, N400 and late positive shift (LPS) to investigate the dynamic changes of the connectivity patterns at different cognitive stages. We found that when differentiating the polyphonic characters with abnormal pronunciations from that with the appreciate ones in audio-visual sentences, significant classification results were obtained based on the coherence in the time window of the P200 component, the correlation in the time window of the N400 component and the coherence and PSI in the time window the LPS component. Moreover, the spatial distributions in these time windows were also different, with the recruitment of frontal sites in the time window of the P200 component, the frontal-central-parietal regions in the time window of the N400 component and the central-parietal sites in the time window of the LPS component. These findings demonstrate that the functional interaction mechanisms are different at different stages of audio-visual integration of polyphonic characters.

Semantic integration of audio-visual information of polyphonic characters in a sentence context: an event-related potential study

In the Chinese language, a polyphone is a kind of special character that has more than one pronunciation, with each pronunciation corresponding to a different meaning. Here, we aimed to reveal the cognitive processing of audio-visual information integration of polyphones in a sentence context using the event-related potential (ERP) method. Sentences ending with polyphones were presented to subjects simultaneously in both an auditory and a visual modality. Four experimental conditions were set in which the visual presentations were the same, but the pronunciations of the polyphones were: the correct pronunciation; another pronunciation of the polyphone; a semantically appropriate pronunciation but not the pronunciation of the polyphone; or a semantically inappropriate pronunciation but also not the pronunciation of the polyphone. The behavioral results demonstrated significant differences in response accuracies when judging the semantic meanings of the audio-visual sentences, which reflected the different demands on cognitive resources. The ERP results showed that in the early stage, abnormal pronunciations were represented by the amplitude of the P200 component. Interestingly, because the phonological information mediated access to the lexical semantics, the amplitude and latency of the N400 component changed linearly across conditions, which may reflect the gradually increased semantic mismatch in the four conditions when integrating the auditory pronunciation with the visual information. Moreover, the amplitude of the late positive shift (LPS) showed a significant correlation with the behavioral response accuracies, demonstrating that the LPS component reveals the demand of cognitive resources for monitoring and resolving semantic conflicts when integrating the audio-visual information.

An ERP study on whether the P600 can reflect the presence of unexpected phonology

In this study, we conducted a new approach to determine whether the P600 could reflect the presence of unexpected phonology. In the experiment, the critical Chinese characters in the poems are either original or substituted by homophones or synonyms. The N400 effect is observed only under the homophonic condition. Late positive shifts are revealed under both homophonic and synonymous conditions, but the amplitude under the homophonic condition is smaller than that under the synonymous condition. The observation of the N400 effect under the homophonic condition indicates that semantic processing occurs in Chinese poem comprehension, while the P600 effect elicited under the homophonic condition is a reflection of unfulfilled semantic expectations. The existence of the late positivity under the synonymous condition reveals that P600 can reflect the presence of unexpected phonology. Interestingly, late positivities under the two conditions both consist of two parts. A discussion ensues wherein these two parts of the late positive shift relate, respectively, to monitoring and resolution processes in language comprehension.

The processing of phonological, orthographical, and lexical information of Chinese characters in sentence contexts: An ERP study

In the current work, we aimed to study the processing of phonological, orthographical, and lexical information of Chinese characters in sentence contexts, as well as to provide further evidence for psychological models. In the experiment, we designed sentences with expected, homophonic, orthographically similar, synonymous, and control characters as endings, respectively. The results indicated that P200 might be related to the early extraction of phonological information. Moreover, it might also represent immediate semantic and orthographic lexical access. This suggested that there might be a dual-route in cognitive processing, where the direct access route and the phonologically mediated access route both exist and interact with each other. The increased N400 under the control condition suggested that both phonological and orthographical information would influence semantic integration in Chinese sentence comprehension. The two positive peaks of the late positive shift might represent the semantic monitoring, and orthographical retrieval and reanalysis processing, respectively. Under the orthographically similar condition, orthographical retrieval and reanalysis processing was more difficult in comparison with the other conditions, which suggested that there might be direct access from orthography to semantic representation in cognitive processing. In conclusion, it was shown that the direct access hypothesis or the dual-route hypothesis could better explain cognitive processing in the brain.

The effects of punctuations in Chinese sentence comprehension: An ERP study

In this paper, we aim to study the effects of Chinese punctuations in sentence comprehension, and to prove metafunctions of Chinese punctuations, namely the ideational, interpersonal and textual metafunctions. By using Chinese sentences containing punctuations as stimuli, an experiment with three tasks is conducted using event-related potential (ERP) method. Focusing on ERP components such as P2, closure positive shift (CPS), late positive shift, N400 and P600, we have proven that: (1) punctuations in Chinese sentences could affect the earlier orthographic extraction processing; (2) punctuations in Chinese sentences could serve on the prosodic boundary in reading; (3) the commas within Chinese sentences could change the syntactic structures of sentences, and play a role of lexical parsing and sentence phrasing, leading the semantic comprehension of sentences to be changed. The results show that ideational and textual metafunctions are present in Chinese punctuations, while the interpersonal metafunction of Chinese punctuations remains to be further identified. This study serves to extend the research of punctuations in linguistics.

Event-related potentials to aversive environmental sounds

Event Abstract Back to Event Event-related potentials to aversive environmental sounds Kinga Gyimesi1, 2*, I Czigler1, T. J. Cox1 and J. Horváth1 1 Institute for Psychology of the Hungarian Academy of Sciences, Hungary 2 Budapest University of Technology and Economics, Hungary Emotionally negative (aversive) sounds and everyday sounds were presented as novel sounds in an auditory 3-stimulus paradigm. Both type of novel sounds elicited the orientation-related P3a component. In comparison to everyday sounds, the aversive sounds elicited a posterior negative component in the 154-250 ms range. The early negativity was followed by a frontal positive wave (372-456 ms). Compared to everyday sounds, the aversive sounds elicited larger late positive shift. The early negativity is considered as an initial effect in a broad neural network including limbic structures, while the late positivity is assumed to be related to the continued (deeper) processing of motivationally significant, memory-related processes. Conference: MMN 09 Fifth Conference on Mismatch Negativity (MMN) and its Clinical and Scientific Applications, Budapest, Hungary, 4 Apr - 7 Apr, 2009. Presentation Type: Poster Presentation Topic: Poster Presentations Citation: Gyimesi K, Czigler I, Cox TJ and Horváth J (2009). Event-related potentials to aversive environmental sounds. Conference Abstract: MMN 09 Fifth Conference on Mismatch Negativity (MMN) and its Clinical and Scientific Applications. doi: 10.3389/conf.neuro.09.2009.05.053 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 24 Mar 2009; Published Online: 24 Mar 2009. * Correspondence: Kinga Gyimesi, Institute for Psychology of the Hungarian Academy of Sciences, Budapest, Hungary, davita81@gmail.com Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Kinga Gyimesi I Czigler T. J Cox J. Horváth Google Kinga Gyimesi I Czigler T. J Cox J. Horváth Google Scholar Kinga Gyimesi I Czigler T. J Cox J. Horváth PubMed Kinga Gyimesi I Czigler T. J Cox J. Horváth Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Event-related potential study to aversive auditory stimuli

In an auditory oddball task emotionally negative (aversive) sounds (e.g. rubbing together of polystyrene) and everyday sounds (e.g. ringing of a bicycle bell) were presented as task-irrelevant (novel) sounds. Both the aversive and the everyday sounds elicited the orientation-related P3a component of the event-related potentials (ERPs). In the 154-250 ms range the ERPs for the aversive sounds were more negative than the ERP of the everyday sounds. For the aversive sounds, this negativity was followed by a frontal positive wave (372-456 ms). The aversive sounds elicited larger late positive shift than the everyday sounds. The early negativity is considered as an initial effect in a broad neural network including limbic structures, while the later is related to the cognitive assessment of the stimuli and to memory-related processes.

ERP Indicators of Learning in Adults

This study investigated learning-related changes in the brain activity of young adults. A group of 29 undergraduate students (18–24 years) participated in a learning study that included a pretest, a training session, and a posttest. Each trial involved presentation of a complex visual stimulus and its spoken "name." Auditory event-related potentials (ERPs) were recorded in response to matching and mismatching names. In the pretest, the participants guessed whether the names were matching the figures. During training they learned the names of a set of simple elements making up the complex figures and were required to master a simple rule for combining the visual and auditory stimuli. The posttest included presentation of the combinations learned during training as well as novel pairings of the same elements. Following training the number of correct responses for learned items doubled and the amplitudes of the auditory ERPs to learned and rule transfer stimuli were more positive than brain waves to the not learned or novel items over most of the analysis window. The ERPs further differentiated between a familiarity response (late positive shift) and learning-specific changes (N2–P3 range). Overall, the findings suggest that ERPs can be a useful tool for learning assessment and offer new insights in the study of individual differences associated with the learning process.

On the Distinctiveness, Independence, and Time Course of the Brain Responses to Syntactic and Semantic Anomalies

We evaluated the distinctiveness, independence, and relative time courses of the event-related brain potentials (ERPs) elicited by syntactically and semantically anomalous words. ERPs were recorded from 13 scalp electrodes while subjects read sentences, some of which contained a selectional restriction violation (semantically anomalous), a verb tense violation (syntactically anomalous), or a doubly anomalous word that violated both selectional restriction and verb tense constraints. Semantic anomalies elicited a monophasic increase in N400 amplitude, whereas syntactic anomalies elicited a late positive shift with an onset around 500 msec and a duration of several hundred msec. Doubly anomalous words elicited both an increase in N400 amplitude and a late positive wave, and these effects summated in an approximately (but not perfectly) linear manner. These results are discussed with respect to the hypotheses that syntactic and semantic processes are separable and independent.

On the Language Specificity of the Brain Response to Syntactic Anomalies: Is the Syntactic Positive Shift a Member of the P300 Family?

Abstract Event-related brain potentials (ERPs) were recorded from 13 scalp electrodes while subjects read sentences, some of which contained either a verb that disagreed in number with the subject noun (syntactic anomaly) or a word in uppercase letters (physical anomaly). Uppercase words elicited the P300 complex of positivities, whereas agreement violations elicited a late positive shift with an onset around 500 msec and a duration of several hundred msec. These effects differed in their morphology, temporal course, amplitude, and scalp distribution. Furthermore, manipulations of the probability-of-occurrence and task relevance of the anomalies had robust effects on the response to uppercase words, but not on the response to agreement violations. Finally, these anomalies had additive effects when agreement-violating uppercase (doubly anomalous) words were presented. These results are taken to be an initial indication that the positive shift elicited by agreement violations is distinct from the P300 response to unexpected, task-relevant anomalies that do not involve the violation of a grammatical rule.

Brain potentials before and during memory scanning

Brain potentials were recorded from 10 normal subjects engaged in a 3-item auditory verbal short-term memory task. A fixed interval (3 s) between the last memory item and the probe was compared to a random interval (1.8–4.2 s with a mean of 3 s). Subjects indicated by button press whether the probe was or was not a member of the memory-set. The same 3-item task was also presented as a counting task and required a button press to the ‘fourth stimulus’ (the probe). The amplitudes of several slow potential shifts preceding and following the probe, and the amplitudes and latencies of the accompanying short duration components (N100, P200) were measured. When the probe appeared at a fixed interval, the amplitude of a slow negative potential in the 300 ms period preceding the probe was slightly larger in the memory than in the counting task. When the probe appeared at a random interval in the memory task, the slow negative shift preceding the probe was absent. Another slow negative shift that peaked at approximately 376 ms after the probe was present in the memory tasks but was absent in the counting task. The amplitude of a late positive shift that peaked at approximately 700 ms after the probe was not different within the memory tasks, or between the memory and counting tasks. N100 amplitude but not P200 amplitude was larger in the memory task when the probe occurred at a fixed than at a random interval. These results suggest that the amplitude of a slow negative shift preceding the probe was related primarily to a temporal expectancy for the appearance of the probe and to a lesser extent to memory processes. In contrast, a slow negative shift that followed the probe occurred only during the memory tasks.

The Effects of Spatial Selective Attention on the Somatosensory Event‐Related Potential

ABSTRACTEvent‐related potentials (ERPs) were recorded during a selective attention task involving weak or strong electrical stimuli delivered to the index fingers of the left and right hands. In an attend weak condition, subjects were asked to count the number of weak stimuli (targets) interspersed amongst strong stimuli (standards) delivered to a designated hand, whilst ignoring a similar set of stimuli delivered to the other hand. In an attend strong condition, subjects were asked to count the number of strong targets interspersed amongst weak stimuli. In both conditions, targets and standards occurred with probabilities of .10 and .40 respectively on each hand. Counting weak targets was found to be more difficult than counting strong targets. The latency of the earliest significant effect of selective attention on ERPs to standards was dependent on stimulus intensity: N80 in the case of weak standards, P105 for strong standards. There was no evidence of a later prolonged negative shift in attended standard ERPs. Rather, an enhanced N150 component post‐centrally was followed by a prolonged positive shift of attended standard ERPs. This Late positive shift had a similar scalp distribution to the late positive component elicited by attended target stimuli.

Event related potentials and time estimation.

ABSTRACTEvent related potentials (ERPs) recorded from the scalp of man were studied during a time estimation task. The principal ERP correlate of mental activity associated with time estimation appeared to be a CNV wave followed by a late positive shift. Latency of CNV termination was correlated with temporal judgments. There was some evidence that the onset of CNV termination occurred prior to the estimated time of occurrence of cortical motor command signals associated with production of the temporal judgments.