N400

Event related potentials (ERPs) have frequently been employed to investigate language comprehension. One of the best researched language-related ERP components is the N400, which is sensitive to various linguistic factors (e.g. plausibility, word frequency, predictability, word-level associations), and is therefore commonly referred to as an index of lexico-semantic memory. Systematic research into electrophysiological indexes of lexico-semantic processing in bilingualism and its comparison with existing monolingual research remains a crucial research avenue. The following review synthesizes the literature on the N400 effects observed in bilingual language comprehension studies in the context of selected models of bilingual lexico-semantic processing (i.e. RHM, BIA+), points to potential reasons behind some contradictory results, presents current trends in ERP bilingual research, identifies gaps in this area of research, and, finally, proposes future research directions.

It has recently been found that during recognition memory tests participants’ pupils dilate more when they view old items compared to novel items. This thesis sought to replicate this novel ‘‘Pupil Old/New Effect’’ (PONE) and to determine its relationship to implicit and explicit mnemonic processes, the veracity of participants’ responses, and the analogous Event-Related Potential (ERP) old/new effect. Across 9 experiments, pupil-size was measured with a video-based eye-tracker during a variety of recognition tasks, and, in the case of Experiment 8, with concurrent Electroencephalography (EEG).

The main findings of this thesis are that:
- the PONE occurs in a standard explicit test of recognition memory but not in “implicit” tests of either perceptual fluency or artificial grammar learning;
- the PONE is present even when participants are asked to give false behavioural answers in a malingering task, or are asked not to respond at all;
- the PONE is present when attention is divided both at learning and during recognition;
- the PONE is accompanied by a posterior ERP old/new effect;
- the PONE does not occur when participants are asked to read previously encountered words without making a recognition decision;
- the PONE does not occur if participants preload an “old/new” response;
- the PONE is not enhanced by repetition during learning.

These findings are discussed in the context of current models of recognition memory and other psychophysiological indices of mnemonic processes. It is argued that together these findings suggest that the increase in pupil-size which occurs when participants encounter previously studied items is not under conscious control and may reflect primarily recollective processes associated with recognition memory.

We aimed to determine whether semantic relatedness between an incoming word and its preceding context can override expectations based on two types of stored knowledge: real-world knowledge about the specific events and states conveyed by a verb, and the verb's broader selection restrictions on the animacy of its argument. We recorded event-related potentials on post-verbal Agent arguments as participants read and made plausibility judgments about passive English sentences. The N400 evoked by incoming animate Agent arguments that violated expectations based on real-world event/state knowledge, was strongly attenuated when they were semantically related to the context. In contrast, semantic relatedness did not modulate the N400 evoked by inanimate Agent arguments that violated the preceding verb’s animacy selection restrictions. These findings suggest that, under these task and experimental conditions, semantic relatedness can facilitate processing of post-verbal animate arguments that violate specific expectations based on real-world event/state knowledge, but only when the semantic features of these arguments match the coarser- grained animacy restrictions of the verb. Animacy selection restriction violations also evoked a P600 effect, which was not modulated by semantic relatedness, suggesting that it was triggered by propositional impossibility. Together, these data indicate that the brain distinguishes between real-world event/state knowledge and animacy-based selection restrictions during online processing.

This study presents the first two ERP reading studies of comma-induced effects of covert (implicit) prosody on syntactic parsing decisions in English. The first experiment used a balanced 2 × 2 design in which the presence/absence of commas determined plausibility (e.g., John, said Mary, was the nicest boy at the party vs. John said Mary was the nicest boy at the party). The second reading experiment replicated a previous auditory study investigating the role of overt prosodic boundaries in closure ambiguities (Pauker et al., 2011). In both experiments, commas reliably elicited CPS components and generally played a dominant role in determining parsing decisions in the face of input ambiguity. The combined set of findings provides further evidence supporting the claim that mechanisms subserving speech processing play an active role during silent reading.

Not much is known about how people comprehend ironic utterances, and to date, most studies have simply compared processing of ironic vs. non-ironic statements. A key aspect of the graded salience hypothesis, distinguishing it from other accounts (such as the standard pragmatic view and direct access view), is that it predicts differences between processing of familiar and unfamiliar ironies. Specifically, if an ironic utterance is familiar, then the ironic interpretation should be available without the need for extra inferential processes, whereas for unfamiliar ironies, the literal interpretation would be computed first, and a mismatch with context would lead to a re-interpretation of the statement as being ironic. We recorded participants’ eye movements while they were reading (Experiment 1), and electrical brain activity while they were listening to (Experiment 2), familiar and unfamiliar ironies compared to non-ironic controls. Results showed disruption to eye movements, and an N400-like effect for unfamiliar ironies only, supporting the predictions of the graded salience hypothesis. In addition, in Experiment 2, a late positivity was found for both familiar and unfamiliar ironic materials, compared to non-ironic controls. We interpret this positivity as reflecting ongoing conflict between the literal and ironic interpretations of the utterance.

Our vocabulary is, at least in principle, infinite. We can create new words combining existing ones in meaningful ways to form new linguistic expressions. The present study investigated the morphological processing of novel compound words in overt speech production. Native speakers of Dutch learned a series of new compounds (e.g. appelgezicht, 'apple-face') that were later used as primes in a morphological priming task. In this protocol, primes were compound words morphologically related to a target's picture name (e.g. appelgezicht was used for a picture of an apple, Dutch appel). The novel primes were compared with corresponding familiar compounds sharing a free morpheme (e.g. appelmoes, 'applesauce') and with unrelated compounds. Participants were required to read aloud words and to name pictures in a long-lag design. Behavioral and event-related potentials (ERPs) data were collected in two sessions, separated by 48 h. Clear facilitation of picture naming latencies was obtained when pictures were paired with morphological related words. Notably, our results show that novel compounds have a stronger priming effect than familiar compounds in both sessions, which is expressed in a marked reduction in target naming latencies and a decrease in the N400 amplitude. These results suggest that participants focused more on the separate constituents when reading novel primes than in the case of existing compounds.

Previous electrophysiological research on human creative cognition has related creative ideation to increased activity in the alpha band, an effect which mainly reflects increased general attentional demands. Research on alpha unrelated to creativity has revealed different functional roles of the upper (semantic processes) and lower (attentional processes) alpha sub-bands. At the same time, the need to dissect creative thinking into specific cognitive operations, such as, semantic processing, re-representation, or conceptual expansion has become evident. The main aim of the reported study was to test whether increased semantic processing demands linked to creating conceptual re-representations of objects required for evaluating alternate uses modulate activity in the upper and/or lower alpha sub-bands. For this purpose, we performed an alternate use evaluation task (AUeT), in which participants saw word pairs representing common uses, alternate uses, and unrelated word pairs, and evaluated whether a given use was common or uncommon (question 1), and how usable it was (question 2). Such an approach allowed us to examine the time-course of semantic processing involved in evaluating alternate uses. Additionally, the results could be contrasted with event-related potential (ERP) studies on creative language and semantic processing. We assumed that demands related to access and integration of semantic information needed to create a re-representation of objects (alternate uses) would be larger than in the case of common uses, which do not require creating a re-representation. This should be reflected in more activity in the alpha band in response to alternate than common uses, which was observed in the analysis of the upper alpha band over parieto-occipital sites. In the lower alpha band, more activity over the left than right anterior sites was observed for alternate uses, which might reflect increased attentional demands. Additionally, in the ERP analysis, alternate uses evoked larger N400 (400–500 ms) amplitudes than common uses, a pattern that extended to later time windows (500–1,000 ms). Overall, the results indicate increased semantic processing demands in alternate use evaluation, possibly linked to the creation of conceptual re-representations.

The uncanny valley hypothesis suggests that robots that are humanoid in appearance elicit positive and empathetic responses, but that there is a point where the robot design is very close to human, the robot becomes repulsive. A possible mechanism underlying this phenomenon is based on the predictive coding theory of neural computations. According to this framework, certain neural systems in the brain can ascribe humanness to a robot that is highly human-like in its appearance, and if the robot’s behavior does not match in realism to the appearance, there will be a processing conflict the neural network will need to resolve. Although this hypothesis is consistent with previous results in the field, empirical work directly testing it is lacking. Here we addressed this gap with a cognitive neuroscience study: We recorded electrical brain activity from the human brain using electroencephalography (EEG) as human subjects viewed images and videos of three agents: A female adult (human), a robot agent closely resembling her (android), and the same robot in a more mechanical appearance (robot). The human and robot had congruent appearance and movement (human with biological appearance and movement; robot with mechanical appearance and movement), and the android had incongruent appearance and movement (biological appearance but mechanical movement). We hypothesized that the android would violate the brain’s predictions since it has a biological appearance, but mechanical movement, whereas the other agents would not lead to such a conflict (robot looks mechanical and moves mechanically; human looks biological and moves biologically). We focused on the N400 ERP component derived from the EEG data. Since the N400 has a greater amplitude for anomalies and violations based on preceding context, we hypothesized the amplitude would be significantly greater for the android in the moving condition than the still condition, whereas the moving and still conditions of the robot and human stimuli would not differ. Our results confirmed out hypothesis, indicating that the uncanny valley might at least partially be due to violations of the brain’s internal predictions about almost-but-not-quite-human robots. Interdisciplinary studies like this one not only allows us to understand the neural basis of human social cognition but also informs robotics about what kind of robots we should design for successful human-robot interaction.

Perceptual information is often ambiguous and we have to deal with such ambiguity to ensure optimal behavior; yet, the mechanisms that our brain uses for processing ambiguous stimuli are not well understood. In the current study, we tested whether there were any common markers of neural processing of ambiguity, regardless of its type. To this end, ERPs (event-related potentials) were elicited under similar experimental conditions by either verbal or non-verbal information: ambiguous figures vs. verbal jokes. It has been suggested that ambiguous graphical information triggers a mis-match conflict at earlier stages of processing, whereas in case of perception of ambiguous written texts, it takes place at later stages, associated with semantic analysis. Results of our experiment show that perception of both ambiguous figures and verbal jokes was related to semantic reversion, as the amplitude of the negative-going N400 component increased in response to both pictorial and verbal stimuli that were correctly identified as having more than one meaning, in contrast to otherwise similar but unambiguous control stimuli.

The topic of synchronization forms a link between nonlinear dynamics and neuroscience. On the one hand, neurobiological research has shown that the synchronization of neuronal activity is an essential aspect of the working principle of the brain. On the other hand, recent advances in the physical theory have led to the discovery of the phenomenon of phase synchronization. A method of data analysis that is motivated by this finding - phase synchronization analysis - has already been successfully applied to empirical data.
The present doctoral thesis ties up to these converging lines of research. Its subject are methodical contributions to the further development of phase synchronization analysis, as well as its application to event-related potentials, a form of EEG data that is especially important in the cognitive sciences.
The methodical contributions of this work consist firstly in a number of specialized statistical tests for a difference in the synchronization strength in two different states of a system of two oscillators. Secondly, in regard of the many-channel character of EEG data an approach to multivariate phase synchronization analysis is presented.
For the empirical investigation of neuronal synchronization a classic experiment on language processing was replicated, comparing the effect of a semantic violation in a sentence context with that of the manipulation of physical stimulus properties (font color). Here phase synchronization analysis detects a decrease of global synchronization for the semantic violation as well as an increase for the physical manipulation. In the latter case, by means of the multivariate analysis the global synchronization effect can be traced back to an interaction of symmetrically located brain areas.
The findings presented show that the method of phase synchronization analysis motivated by physics is able to provide a relevant contribution to the investigation of event-related potentials in the cognitive sciences.

Research has shown neural changes following second language (L2) acquisition after weeks or months of instruction. But are such changes detectable even earlier than previously shown? The present study examines the electrophysiological changes underlying the earliest stages of second language vocabulary acquisition by recording event-related potentials (ERPs) within the first week of learning. Adult native English speakers with no previous Spanish experience completed less than four hours of Spanish vocabulary training, with pre-and post-training ERPs recorded to a backward translation task. Results indicate that beginning L2 learners show rapid neural changes following learning, manifested in changes to the N400 e an ERP component sensitive to lexicosemantic processing and degree of L2 proficiency. Specifically, learners in early stages of L2 acquisition show growth in N400 amplitude to L2 words following learning as well as a backward translation N400 priming effect that was absent pre-training. These results were shown within days of minimal L2 training, suggesting that the neural changes captured during adult second language acquisition are more rapid than previously shown. Such findings are consistent with models of early stages of bilingualism in adult learners of L2 (e.g. Kroll and Stewart's RHM) and reinforce the use of ERP measures to assess L2 learning.

Introduction: This study examined the effect of proficiency level on the second Language (L2)
syntactic and semantic processing by addressing the role of procedural and declarative memory
systems in light of the Declarative/Procedural (DP) model. The primary purpose was to determine
to what extent proficiency accounts for native-like language processing in L2 in adult bilinguals
who learned English (L2) after the age of 15 under explicit instruction.
Methods: Using a mixed-method design and an oddball violation paradigm, we examined the
functional neural correlates of syntactic and semantic processing in two groups of Persian-English
bilinguals (L1=Persian, L2=English; N=10 high-proficient, N=10 pre-intermediate levels; Gender=
Female; mean age=25.50 years, SD = 5.09 years, age range = 19-35 years of age) across 6 different
conditions. They included a visual stimulus task of 240 English sentences with three different
experimental conditions (violated regular past forms or phrase structure rules or final-word semantic
violation) and three control conditions (sets of correct sentences for each experimental condition).
Both groups started learning English late (age of onset=15+) and under an explicit learning context.
To evaluate the effect of L2 proficiency, Event-related potentials (ERPs) to target words in each
condition were elicited across the N400 time window (300-500 ms) and the P600 time window
(500-700 ms).
Results: Results showed different cortical responses in the two groups. Upon processing the
violated forms, high-proficient subjects showed more native-like patterns of scalp activity in both
lexical-semantic and syntactic processing. In contrast, less proficient learners have shown delayed
onsets and or peaks of components, reduced amplitudes, or absent components in some regions. For
instance, the difference in N400 amplitude for the incorrect regular past conditions was observed
only in the pre-intermediate (PI) subjects in the O1 channel. This finding is compatible with the DP
Model in that at lower levels of L2 proficiency, the participants show N400s or N400-like posterior
negativities instead of Anterior Negativities (ANs). This finding shows the initial reliance on the
declarative memory system for syntactic processing at lower levels of L2.
Conclusion: Our findings suggest that attained proficiency was a more determinant factor in the L1-
like cortical representation of L2 than the age of acquisition and or the type of instruction/context.
Several brain areas, similar to those observed for L1, were activated during L2 syntactic processing
in high-proficient subjects addressing their reliance on the procedural memory system for syntactic
processing to gain more proficiency. For instance, our results showed a significant difference in
N400 amplitude for the incorrect regular past conditions in O1 for the PI subjects, which shows
the initial reliance on the declarative memory system for syntactic processing at lower levels of L2.

Readers typically experience processing difficulty when they encounter a word that is anomalous within the local context, such as ‘‘The cat picked up the chainsaw.’’ In an ERP study, we demonstrate that by placing such a sentence in a fictional scenario that is well known to the reader (e.g., a Tom and Jerry cartoon), the N400 effect usually associated with these pragmatic anomalies can be eliminated. This finding suggests that readers can rapidly integrate information from their common ground while interpreting incoming text and provides further evidence that incoming words are immediately evaluated within the global discourse.

Hay muchos estudios que confirman que las personas con alzheimer no pierden la memoria musical, es decir, se preserva esta parte de la memoria; en esta investigación se estudio por medio de señales encefalográficas la memoria musical en personas normales, se corroboró por medio de potenciales evocados que la región de la memoria se activa cuando las personas escucharon un estímulo específico diferente al que recuerdan, en este caso una melodía musical con violaciones en tono o desafinada. Este estudio permite evaluar la memoria musical en personas con deterioro cognitivo leve y alzheimer.
Link: http://sedici.unlp.edu.ar/handle/10915/46281

Experimental studies using fictional moral dilemmas indicate that both automatic emotional processes and controlled cognitive processes contribute to moral judgments. However, not much is known about how people process socio-normative violations that are more common to their everyday life, nor the time-course of these processes. Thus, we recorded participants’ electrical brain activity while they were reading vignettes that either contained morally acceptable versus unacceptable information, or text materials that contained information which was either consistent or inconsistent with their general world knowledge. A first ERP positivity peaking at about 200 ms after critical word onset (P200) was larger when this word involved a socio-normative or knowledge-based violation. Subsequently, knowledge-inconsistent words triggered a larger centroparietal ERP negativity at about 320 ms (N400), indicating an influence on meaning construction. By contrast, a larger ERP positivity (LPP), which also started at about 320 ms after critical word onset, was elicited by morally unacceptable compared to acceptable words. We take this ERP positivity to reflect an implicit evaluative (good-bad) categorization process that is engaged during the online processing of moral transgressions.

Which cognitive processes are reflected by the N400 in ERPs is still controversial. Various recent articles (Lau et al., 2008; Brouwer et al., 2012) have revived the idea that only lexical pre-activation processes (such as automatic spreading activation, ASA) are strongly supported, while post-lexical integrative processes are not. Challenging this view, the present ERP study replicates a behavioral study by McKoon and Ratcliff (1995) who demonstrated that a prime-target pair such as finger − hand shows stronger priming when a ma- jority of other pairs in the list share the analogous semantic relationship (here: part-whole), even at short stim- ulus onset asynchronies (250 ms). We created lists with four different types of semantic relationship (syn- onyms, part-whole, category-member, and opposites) and compared priming for pairs in a consistent list with those in an inconsistent list as well as unrelated items. Highly significant N400 reductions were found for both relatedness priming (unrelated vs. inconsistent) and relational priming (inconsistent vs. consistent). These data are taken as strong evidence that N400 priming effects are not exclusively carried by ASA-like mechanisms during lexical retrieval but also include post-lexical integration in working memory. We link the present find- ings to a neurocomputational model for relational reasoning (Knowlton et al., 2012) and to recent discussions of context-dependent conceptual activations (Yee and Thompson-Schill, 2016).

Infants employ sophisticated mechanisms to acquire their first language, including some that rely on taking the perspective of adults as speakers or listeners. When do infants first show awareness of what other people understand? We tested 14-month-old infants in two experiments measuring event-related potentials. In Experiment 1, we established that infants produce the N400 effect, a brain signature of semantic violations, in a live object naming paradigm in the presence of an adult observer. In Experiment 2, we induced false beliefs about the labeled objects in the adult observer to test whether infants keep track of the other person’s comprehen- sion. The results revealed that infants reacted to the semantic incongruity heard by the other as if they encountered it themselves: they exhibited an N400-like response, even though labels were congruous from their perspective. This finding demon- strates that infants track the linguistic understanding of social partners.

A B S T R A C T Uncanny valley refers to humans' negative reaction to almost-but-not-quite-human agents. Theoretical work proposes prediction violation as an explanation for uncanny valley but no empirical work has directly tested it. Here, we provide evidence that supports this theory using event-related brain potential recordings from the human scalp. Human subjects were presented images and videos of three agents as EEG was recorded: a real human, a mechanical robot, and a realistic robot in between. The real human and the mechanical robot had congruent appearance and motion whereas the realistic robot had incongruent appearance and motion. We hypothesize that the appearance of the agent would provide a context to predict her movement, and accordingly the perception of the realistic robot would elicit an N400 effect indicating the violation of predictions, whereas the human and the mechanical robot would not. Our data confirmed this hypothesis suggesting that uncanny valley could be explained by violation of one's predictions about human norms when encountered with realistic but artificial human forms. Importantly, our results implicate that the mechanisms underlying perception of other individuals in our environment are predictive in nature.

The ability of schizophrenia patients to access metaphorical meaning was studied on the basis of psycholinguistic
models of metaphor processing. ERPs were recorded from 20 schizophrenic and 20 control participants who were
asked to read metaphorical, literal, and incongruous sentences and to judge their meaningfulness. In all participants,
incongruous endings to sentences evoked the most negative N400 amplitude, whereas literal endings evoked more
negative N400 amplitude than metaphorical ones, consistent with the direct model of metaphor processing. Although
the patients had ERPs patterns that were similar to controls, they exhibited a more negative N400 amplitude for all
sentences, LPC amplitude reduction, and latency delay in both components. The results suggest that schizophrenics
have no specific anomalies in accessing the meaning of metaphors but are less efficient in integrating the semantic
context of all sentencesFboth figurative and literal.

The effect of concreteness has been heavily studied on nouns. However, there are scant reports on the effect for verbs. The resent research independently manipulated concreteness and word class of Chinese disyllabic words in tasks that required different depths of semantic processing: a lexical decision task and a semantic relatedness judgment task. The results replicated the concreteness effect for nouns, indicating that concrete nouns elicited larger N400 responses than abstract nouns with a broad distribution over the scalp, irrespective of the task demands. Similar to the findings from English unambiguous verbs, the concreteness effect for Chinese verbs was also robustly observed from frontal to posterior electrodes in both tasks. These results suggest that when Chinese nouns and verbs are typical and unambiguous in both meanings and word classes, the similar topographic distributions of the N400 components reflect the same underlying cause(s) of the concreteness effect for these two word classes.