Event-related Brain Potential Experiment Research Articles

The role of discourse in long-distance dependency formation

ABSTRACT Sentences with filler-gap dependency are more difficult to process than those without, as reflected by event-related brain potentials (ERPs) such as sustained left anterior negativity (SLAN). The cognitive processes underlying SLAN may support associating a filler with a temporally distant gap in syntactic representation. Alternatively, processing filler-gap dependencies in the absence of a supportive context involves additional discourse processing. The present study conducted an ERP experiment that manipulated syntactic complexity (subject–object–verb [SOV] and object–subject–verb [OSV]) and discourse (the supportive and non-supportive context) in Japanese. The result showed a SLAN in OSV relative to SOV in the non-supportive but not the supportive context, which suggests that the difficulty involved in processing OSV in Japanese is largely due to a pragmatic factor. The present study contributes to a better understanding of how the language-processing system builds long-distance dependency by interacting with the memory system.

Meaning before grammar: A review of ERP experiments on the neurodevelopmental origins of semantic processing.

According to traditional linguistic theories, the construction of complex meanings relies firmly on syntactic structure-building operations. Recently, however, new models have been proposed in which semantics is viewed as being partly autonomous from syntax. In this paper, we discuss some of the developmental implications of syntax-based and autonomous models of semantics. We review event-related brain potential (ERP) studies on semantic processing in infants and toddlers, focusing on experiments reporting modulations of N400 amplitudes using visual or auditory stimuli and different temporal structures of trials. Our review suggests that infants can relate or integrate semantic information from temporally overlapping stimuli across modalities by 6 months of age. The ability to relate or integrate semantic information over time, within and across modalities, emerges by 9 months. The capacity to relate or integrate information from spoken words in sequences and sentences appears by 18 months. We also review behavioral and ERP studies showing that grammatical and syntactic processing skills develop only later, between 18 and 32 months. These results provide preliminary evidence for the availability of some semantic processes prior to the full developmental emergence of syntax: non-syntactic meaning-building operations are available to infants, albeit in restricted ways, months before the abstract machinery of grammar is in place. We discuss this hypothesis in light of research on early language acquisition and human brain development.

Why are verbal nouns more verbal than finite verbs? New insights into the interpretation of the P200 verbal signature

Traditionally, languages are assumed to minimally manifest a distinction between nouns and verbs. This assumption has occasionally been debated in the theoretical linguistic literature, in particular in the context of challenging verbal noun constructions that simultaneously manifest nominal and verbal features. From a psycholinguistic perspective, one of the most promising diagnostic criteria for determining whether a given word belongs to the category NOUN or VERB is an event-related brain potential (ERP) component, P200, whose amplitude is larger for verbs than for nouns. So far, a challenge for the interpretation of the P200 has been whether this component reflects verbal (e.g., action) semantics, lexical category or verb-related morphological operation. In the present study we report an ERP experiment whose goal was to contribute to a better understanding of the nature of the “verbal” P200 component by monitoring the comprehension of Polish morphologically related finite verbs, converbs, and verbal nouns. Thereby, we manipulated the syntactic category and morphological complexity of the critical words while keeping their semantics identical. The results show that finite verbs engender a smaller amplitude of the P200 component than less prototypical “verbs” such as verbal nouns and converbs. Based on this observation, we argue that the P200 component reflects the brain activation triggered by the demands of verb-related morphological integration processes performed on the verbal base of derived forms.

Event-related brain potential correlates of words’ emotional valence irrespective of arousal and type of task

Many Event-Related brain Potential (ERP) experiments have explored how the two main dimensions of emotion, arousal and valence, affect linguistic processing. However, the heterogeneity of experimental paradigms and materials has led to mixed results. In the present study, we aim to clarify words’ emotional valence effects on ERP when arousal is controlled, and determine whether these effects may vary as a function of the type of task performed. For these purposes, we designed an ERP experiment with the valence of words manipulated, and arousal equated across valences. The participants performed two types of task: in one, they had to read aloud each word, written in black on a white background; in the other, they had to name the color of the ink in which each word was written. The results showed the main effects of valence irrespective of task, and no interaction between valence and task. The most marked effects of valence were in response to negative words, which elicited an Early Posterior Negativity (EPN) and a Late Positive Complex (LPC). Our results suggest that, when arousal is controlled, the cognitive information in negative words triggers a ‘negativity bias’, these being the only words able to elicit emotion-related ERP modulations. Moreover, these modulations are largely unaffected by the types of task explored here.

The dysfunction of face processing in patients with internet addiction disorders: an event-related potential study.

To investigate face processing in patients with internet addiction disorders (IAD), an event-related brain potential experiment was conducted in IAD patients and healthy age-matched controls in which participants were instructed to classify each stimulus (face vs. nonface object) as quickly and accurately as possible. Although we did not find a significant difference in the performance between two groups, both the N110 and the P2 components in response to faces were larger in the IAD group than in the control group, whereas the N170 to faces decreased in the IAD group than in the control group. In addition, the source analysis of event-related potential components showed different generators between two groups. These data indicated that there was a dysfunction of face processing in IAD patients and the underlying mechanism of processing faces could be different from healthy individuals.

Violating body movement semantics: Neural signatures of self-generated and external-generated errors

How do we recognize ourselves as the agents of our actions? Do we use the same error detection mechanisms to monitor self-generated vs. externally imposed actions? Using event-related brain potentials (ERPs), we identified two different error-monitoring loops involved in providing a coherent sense of the agency of our actions. In the first ERP experiment, the participants were embodied in a virtual body (avatar) while performing an error-prone fast reaction time task. Crucially, in certain trials, participants were deceived regarding their own actions, i.e., the avatar movement did not match the participant's movement. Self-generated real errors and false (avatar) errors showed very different ERP signatures and with different processing latencies: while real errors showed a classical frontal-central error-related negativity (Ne/ERN), peaking 100ms after error commission, false errors elicited a larger and delayed parietal negative component (at about 350–400ms). The violation of the sense of agency elicited by false avatar errors showed a strong similarity to ERP signatures related to semantic or conceptual violations (N400 component). In a follow-up ERP control experiment, a subset of the same participants merely acted as observers of the avatar correct and error movements. This experimental situation did not elicit the N400 component associated with agency violation. Thus, the results show a clear neural dissociation between internal and external error-monitoring loops responsible for distinguishing our self-generated errors from those imposed externally, opening new avenues for the study of the mental processes underlying the integration of internal and sensory feedback information while being actors of our own actions.

An ERP Study of Causative Cleft Construction in Japanese: Evidence for the Preference of Shorter Linear Distance in Sentence Comprehension.

This study examined the processing of two types of Japanese causative cleft constructions (subject-gap vs. object-gap) by conducting an event-related brain potential experiment to clarify the processing mechanism of long-distance dependencies. The results demonstrated that the subject-gap constructions elicited larger P600 effects than the object-gap constructions. Based on these findings, we argue that the linear distance rather than the structural distance between the extracted argument (filler) and its original gap position is a crucial factor for determining processing costs of gap-filler dependency in Japanese causative cleft constructions. This argument indicates that (at least) some types of long-distance dependencies are sensitive to linear distance.

The interplay between referential processing and local syntactic/semantic processing: ERPs to written Chinese discourse

Two event-related brain potential experiments were conducted to investigate the functional interplay between discourse-level referential processing and local syntactic/semantic processing of phrases. We manipulated both the syntactic/semantic coherence of a noun phrase (NP) and the referential ambiguity of the same NP. Incoherence of the NP elicited a P600 effect in both experiments. Referential ambiguities elicited a sustained negativity (Nref) in a subset of the participants in both experiments. Crucially, among participants showing robust Nref effects to referential ambiguity in the coherent condition, Nref effects were absent when the NP was incoherent. These results provide evidence against theories in which referential processing is functionally independent of local syntactic/semantic processing of phrases. Instead, a local phrase anomaly can block aspects of referential processing concerning ambiguity.

Processing of Japanese Cleft Constructions in Context: Evidence from Event-Related Brain Potentials

Numerous studies have found "subject gap preference" in relative clauses and cleft constructions in English, French, and other languages. In contrast, previous studies have reported "object gap preference" in cleft constructions in Japanese. However, the effect of integrating a filler and its gap may be influenced by the effect of transitional probabilities, so previous studies confounded these two factors. This study explores processing asymmetries in Japanese cleft constructions by conducting an event-related brain potential experiment by controlling transitional probabilities. The results demonstrate that the subject gap preference in Japanese is well aligned with that observed in other languages, suggesting that subject gap preference is a universal aspect of language comprehension.

Cross-linguistic variation in the neurophysiological response to semantic processing: Evidence from anomalies at the borderline of awareness

The N400 event-related brain potential (ERP) has played a major role in the examination of how the human brain processes meaning. For current theories of the N400, classes of semantic inconsistencies which do not elicit N400 effects have proven particularly influential. Semantic anomalies that are difficult to detect are a case in point (“borderline anomalies”, e.g. “After an air crash, where should the survivors be buried?”), engendering a late positive ERP response but no N400 effect in English (Sanford, Leuthold, Bohan, & Sanford, 2011). In three auditory ERP experiments, we demonstrate that this result is subject to cross-linguistic variation. In a German version of Sanford and colleagues′ experiment (Experiment 1), detected borderline anomalies elicited both N400 and late positivity effects compared to control stimuli or to missed borderline anomalies. Classic easy-to-detect semantic (non-borderline) anomalies showed the same pattern as in English (N400 plus late positivity). The cross-linguistic difference in the response to borderline anomalies was replicated in two additional studies with a slightly modified task (Experiment 2a: German; Experiment 2b: English), with a reliable LANGUAGE×ANOMALY interaction for the borderline anomalies confirming that the N400 effect is subject to systematic cross-linguistic variation. We argue that this variation results from differences in the language-specific default weighting of top-down and bottom-up information, concluding that N400 amplitude reflects the interaction between the two information sources in the form-to-meaning mapping.

Are depictive gestures like pictures? Commonalities and differences in semantic processing

Conversation is multi-modal, involving both talk and gesture. Does understanding depictive gestures engage processes similar to those recruited in the comprehension of drawings or photographs? Event-related brain potentials (ERPs) were recorded from neurotypical adults as they viewed spontaneously produced depictive gestures preceded by congruent and incongruent contexts. Gestures were presented either dynamically in short, soundless video-clips, or statically as freeze frames extracted from gesture videos. In a separate ERP experiment, the same participants viewed related or unrelated pairs of photographs depicting common real-world objects. Both object photos and gesture stimuli elicited less negative ERPs from 400 to 600 ms post-stimulus when preceded by matching versus mismatching contexts (dN450). Object photos and static gesture stills also elicited less negative ERPs between 300 and 400 ms post-stimulus (dN300). Findings demonstrate commonalities between the conceptual integration processes underlying the interpretation of iconic gestures and other types of image-based representations of the visual world.

Selection of independent components representing event-related brain potentials: A data-driven approach for greater objectivity

Following the development of increasingly precise measurement instruments and fine-grain analysis tools for electroencephalographic (EEG) data, analysis of single-trial event-related EEG has considerably widened the utility of this non-invasive method to investigate brain activity.Recently, independent component analysis (ICA) has become one of the most prominent techniques for increasing the feasibility of single-trial EEG. This blind source separation technique extracts statistically independent components (ICs) from the EEG raw signal. By restricting the signal analysis to those ICs representing the processes of interest, single-trial analysis becomes more flexible.Still, the selection-criteria for in- or exclusion of certain ICs are largely subjective and unstandardized, as is the actual selection process itself.We present a rationale for a bottom-up, data-driven IC selection approach, using clear-cut inferential statistics on both temporal and spatial information to identify components that significantly contribute to a certain event-related brain potential (ERP). With time-range being the only necessary input, this approach considerably reduces the pre-assumptions for IC selection and promotes greater objectivity of the selection process itself.To test the validity of the approach presented here, we present results from a simulation and re-analyze data from a previously published ERP experiment on error processing. We compare the ERP-based IC selections made by our approach to the selection made based on mere signal power. The comparison of ERP integrity, signal-to-noise ratio, and single-trial properties of the back-projected ICs outlines the validity of the approach presented here. In addition, functional validity of the extracted error-related EEG signal is tested by investigating whether it is predictive for subsequent behavioural adjustments.

The phonemic restoration effect reveals pre-N400 effect of supportive sentence context in speech perception

The phonemic restoration effect refers to the tendency for people to hallucinate a phoneme replaced by a non-speech sound (e.g., a tone) in a word. This illusion can be influenced by preceding sentential context providing information about the likelihood of the missing phoneme. The saliency of the illusion suggests that supportive context can affect relatively low (phonemic or lower) levels of speech processing. Indeed, a previous event-related brain potential (ERP) investigation of the phonemic restoration effect found that the processing of coughs replacing high versus low probability phonemes in sentential words differed from each other as early as the auditory N1 (120–180 ms post-stimulus); this result, however, was confounded by physical differences between the high and low probability speech stimuli, thus it could have been caused by factors such as habituation and not by supportive context. We conducted a similar ERP experiment avoiding this confound by using the same auditory stimuli preceded by text that made critical phonemes more or less probable. We too found the robust N400 effect of phoneme/word probability, but did not observe the early N1 effect. We did however observe a left posterior effect of phoneme/word probability around 192–224 ms—clear evidence of a relatively early effect of supportive sentence context in speech comprehension distinct from the N400.

Semantics does not need a processing license from syntax in reading Chinese.

Two event-related brain potential experiments were conducted to investigate whether there is a functional primacy of syntactic structure building over semantic processes during Chinese sentence reading. In both experiments, we found that semantic interpretation proceeded despite the impossibility of a well-formed syntactic analysis. In Experiment 1, we found an N400 difference between combined syntactic category and semantic violations and single syntactic violations. This finding is inconsistent with earlier German and French studies (e.g., Friederici, Gunter, Hahne, & Mauth, 2004; Friederici, Steinhauer, & Frisch, 1999; Hahne & Friederici, 2002) showing that semantic integration does not proceed for words of the wrong syntactic category. In Experiment 2, we used a design that was very similar to that used in earlier German and French studies, but semantic violations still evoked an N400, irrespective of a simultaneous syntactic category violation. We argue against processing models that do not allow for semantic integration of a word unless it can be grammatically attached to the developing phrase structure tree. Rather, language experience may modulate the mode of interplay between syntax and semantics.

Mapping ERP patterns from heterogeneous datasets: A simulation study

Haishan Liu, Gwen Frishkoff, Robert Frank & Dejing Dou Department of Computer and Information Science, University of Oregon, USA NeuroInformatics Center, University of Oregon, USA Language Imaging Laboratory, Medical College of Wisconsin, USA Introduction: We describe an ontology-based method for representation and integration of neuroscience data, with an application to event-related brain potentials (ERPs). ERP datasets from different labs are highly heterogeneous, in that they are acquired in different experiment contexts and may be analyzed and described using different methods. To address this issue, we use data mining to discover mappings across ERP patterns derived from alternative analysis methods and from datasets that are summarized using different spatial and temporal measures. We then use the discovered mappings to develop machine-readable descriptions of ERP patterns, or “ontologies” [1]. The resulting ontologies are being used to support data sharing and cross-laboratory analysis of ERP experiment results within our Neural Electromagnetic Ontologies consortium [2].

The Mental Scale in Anchoring Effects: Evidence from Event-Related Potentials

There are two main models accounting for anchoring effects: the anchoring and adjustment heuristic and selective accessibility model.Further,anchors can be externally provided or self-generated.Considering prior studies researchers of the prior studies found that the adjustment heuristic model accounted more for anchoring effects in the case of responding to self-generated anchors,while the SA model accounted more for responses to externally provided anchors.In the present study,a mental scale was first introduced to distinguish the effortful adjustment process from effortless accessibility,using an event-related brain potential(ERP) technique.We hypothesized that the coarseness of the scale would influence the process related to the response to self-generated anchors but not that related to experimenter provided anchors. Two ERP experiments on young normal subjects examined the impact of a mental scale on responses to self-generated anchors and externally provided anchors,respectively.We also designed a new paradigm for ERP recording.In Experiment 1, higher or lower numbers as externally provided anchors were presented as cues on the screen;the participants' task was to estimate the quantity of dots in a target circle,analogous to the two-stage standard anchoring paradigm.In Experiment 2,the cues serving as self-generated anchors were the circles for which the participants had already estimated the number of the dots,analogous to the one-stage anchoring paradigm.Behavioral results and ERP results were collected for statistical analysis. Behavioral results validated the effectiveness of the mental scale in diminishing the anchoring bias in the case of responding to self-generated anchors.Adjustment on a coarser scale with fewer categories resulted in a greater skewness from the anchors.Further,ERP results showed a scale effect in the anchoring process even in the case of responding to self-generated anchors too.A positive deflection appeared at 250~800 ms after target onset,and the amplitude of this deflection was more positive in the finer scale condition.Source localization found two free dipoles: one was at the lingual gyrus;the other at the parietal lobe.In the anchoring process,an N300 component was the only component that responded to externally provided anchors and whose amplitude was not influenced by the mental scales.The results of dipole analysis showed that N300 was localized at the cingulate gyrus. In conclusion,the two experiments in the present research showed that the manipulation of the mental scale was proficient in anchoring effects only in the case of responding to self-generated anchors,when the true adjustment process was invoked.ERP results provided more evidence of the neural correlate of anchoring effects.An N300 component was related to the accessibility process responding to externally provided anchors,and the positive deflection at 250~800 ms poststimulus,which was modulated by the mental scale,was related to the adjustment process responding to self-generated anchors.In all,our findings provided electrophysiological evidence for the dual nature of anchoring effects.Whether anchoring serves the purpose of adjustment or accessibility is subject to the relevant context,which is consistent with the two-system review.Although anchoring leads to judgment bias,anchoring effects reflect the flexible intelligence of human beings.

Selective attention to sound location or pitch studied with event‐related brain potentials and magnetic fields

Event-related brain potentials (ERPs) and magnetic fields (ERFs) were used to compare brain activity associated with selective attention to sound location or pitch in humans. Sixteen healthy adults participated in the ERP experiment, and 11 adults in the ERF experiment. In different conditions, the participants focused their attention on a designated sound location or pitch, or pictures presented on a screen, in order to detect target sounds or pictures among the attended stimuli. In the Attend Location condition, the location of sounds varied randomly (left or right), while their pitch (high or low) was kept constant. In the Attend Pitch condition, sounds of varying pitch (high or low) were presented at a constant location (left or right). Consistent with previous ERP results, selective attention to either sound feature produced a negative difference (Nd) between ERPs to attended and unattended sounds. In addition, ERPs showed a more posterior scalp distribution for the location-related Nd than for the pitch-related Nd, suggesting partially different generators for these Nds. The ERF source analyses found no source distribution differences between the pitch-related Ndm (the magnetic counterpart of the Nd) and location-related Ndm in the superior temporal cortex (STC), where the main sources of the Ndm effects are thought to be located. Thus, the ERP scalp distribution differences between the location-related and pitch-related Nd effects may have been caused by activity of areas outside the STC, perhaps in the inferior parietal regions.

Role of the Corpus Callosum in Speech Comprehension: Interfacing Syntax and Prosody

The role of the corpus callosum (CC) in the interhemispheric interaction of prosodic and syntactic information during speech comprehension was investigated in patients with lesions in the CC, and in healthy controls. The event-related brain potential experiment examined the effect of prosodic phrase structure on the processing of a verb whose argument structure matched or did not match the prior prosody-induced syntactic structure. While controls showed an N400-like effect for prosodically mismatching verb argument structures, thus indicating a stable interplay between prosody and syntax, patients with lesions in the posterior third of the CC did not show this effect. Because these patients displayed a prosody-independent semantic N400 effect, the present data indicate that the posterior third of the CC is the crucial neuroanatomical structure for the interhemispheric interplay of suprasegmental prosodic information and syntactic information.

The effects of stress and statistical cues on continuous speech segmentation: An event-related brain potential study

The study of the processes involved in speech segmentation has gained special relevance in recent years by trying to establish what type of information listeners use to segment the speech signal into words. An event-related brain potential experiment was conducted in order to understand how two of these cues (statistical and stress cues) interact. The experiment consisted of the presentation of artificial speech streams in which words were marked either by statistical cues alone, or by a combination of statistical and stress cues. As a baseline, comparison streams were also created with the same syllables but organized in random order. Results showed an N400 component that marks the on-line segmentation of speech into words, and an increased positivity (P2 component) for languages that include both types of cues. Possible implications of these results for the process of speech segmentation are discussed.

Thematic role assignment in patients with Broca's aphasia: Sentence–picture matching electrified

An event-related brain potential experiment was carried out to investigate on-line thematic role assignment during sentence–picture matching in patients with Broca's aphasia. Subjects were presented with a picture that was followed by an auditory sentence. The sentence either matched the picture or mismatched the visual information depicted. Sentences differed in complexity, and ranged from simple active semantically irreversible sentences to passive semantically reversible sentences. ERPs were recorded while subjects were engaged in sentence–picture matching. In addition, reaction time and accuracy were measured. Three groups of subjects were tested: Broca patients ( N = 10), non-aphasic patients with a right hemisphere (RH) lesion ( N = 8), and healthy aged-matched controls ( N = 15). The results of this study showed that, in neurologically unimpaired individuals, thematic role assignment in the context of visual information was an immediate process. This in contrast to patients with Broca's aphasia who demonstrated no signs of on-line sensitivity to the picture–sentence mismatches. The syntactic contribution to the thematic role assignment process seemed to be diminished given the reduction and even absence of P600 effects. Nevertheless, Broca patients showed some off-line behavioral sensitivity to the sentence–picture mismatches. The long response latencies of Broca's aphasics make it likely that off-line response strategies were used.