Event related brain potentials (ERPs)

The Wason Selection Task (WST) is a well-known test of reasoning in which one turns over cards to test a rule about the two faces. Modifications were made to the WST to enable more direct and analytical investigation of reasoning processes. The modifications included extensive training to reduce variations in task interpretation, isolation of working memory in the decision phase, a separate rule for each card and variations in the form of the rule (number-letter as well as letter-number), separate scoring for each card, and inclusion of control cards that could be recognized by features without relational processing. The cognitive complexity of each card was also analyzed to enable investigation of this factor. Behavioral and event-related potential data were recorded. Negative cards differed from positive cards and control cards were differentiated from cards involved in inferences. The N2 component differentiated the negative conditions (not-P, not-Q cards) from the positive conditions (P, Q cards). The P3 component was largest for control and P cards (the simpler conditions). The late slow wave tended to show more sustained processing of not-P, not-Q and Q cards and was little influenced by the simpler control and P cards. Effects were interpreted in terms of cognitive complexity. In particular, the negative conditions had a larger N2 responses than the positive conditions, reflecting greater cognitive complexity of the former and their sustained processing.

A B S T R A C T First language (L1) attrition is a socio-linguistic circumstance where second language (L2) learning coincides with changes in exposure and use of the native-L1. Attriters often report experiencing a decline in automaticity or proficiency in their L1 after a prolonged period in the L2 environment, while their L2 proficiency continues to strengthen. Investigating the neurocognitive correlates of attrition alongside those of late L2 acquisition addresses the question of whether the brain mechanisms underlying both L1 and L2 processing are strongly determined by proficiency, irrespective of whether the language was acquired from birth or in adulthood. Using event-related-potentials (ERPs), we examined lexical-semantic processing in Italian L1 attriters, compared to adult Italian L2 learners and to Italian monolingual native speakers. We contrasted the processing of classical lexical-semantic violations (Mismatch condition) with sentences that were equally semantically implausible but arguably trickier, as the target-noun was " swapped " with an orthographic neighbor that differed only in its final vowel and gender-marking morpheme (e.g., cappello (hat) vs. cappella (chapel)). Our aim was to determine whether sentences with such " confusable nouns " (Swap condition) would be processed as semantically correct by late L2 learners and L1 attriters, especially for those individuals with lower Italian proficiency scores. We found that lower-proficiency Italian speakers did not show significant N400 effects for Swap violations relative to correct sentences, regardless of whether Italian was the L1 or the L2. Crucially, N400 response profiles followed a continuum of " nativelikeness " predicted by Italian proficiency scores – high-proficiency attriters and high-proficiency Italian learners were indistinguishable from native controls, whereas attriters and L2 learners in the lower-proficiency range showed significantly reduced N400 effects for " Swap " errors. Importantly, attriters and late L2 learners did not differ in their N400 responses when they belonged to the same proficiency subgroup. Attriters also showed an enhanced P600 response to both kinds of lexical-semantic anomalies, which we discuss as reflecting increased conflict-monitoring and conscious " second thought " processes specifically in attriters. Our findings provide some of the first ERP evidence of attrition effects, and are compatible with accounts of ongoing neuroplasticity for language in adulthood. Proficiency, rather than age-of-acquisition, seems to be the key factor in modulating certain neurocognitive responses, not only within L2 learners but also in L1 attriters.

The present event-related brain potential (ERP) study investigates mechanisms underlying the processing of morphosyntactic information during real-time auditory sentence comprehension in French. Employing an auditory-visual sentence-picture matching paradigm, we investigated two types of anomalies using entirely grammatical auditory stimuli: (i) semantic mismatches between visually presented actions and spoken verbs, and (ii) number mismatches between visually presented agents and corresponding morphosyntactic number markers in the spoken sentences (determiners, pronouns in liaison contexts, and verb-final "inflection"). We varied the type and amount of number cues available in each sentence using two manipulations. First, we manipulated the verb type, by using verbs whose number cue was audible through subject (clitic) pronoun liaison (liaison verbs) as well as verbs whose number cue was audible on the verb ending (consonant-final verbs). Second, we manipulated the pre-verbal context: each sentence was preceded either by a neutral context providing no number cue, or by a subject noun phrase containing a subject number cue on the determiner. Twenty-two French-speaking adults participated in the experiment. While sentence judgment accuracy was high, participants' ERP responses were modulated by the type of mismatch encountered. Lexico-semantic mismatches on the verb elicited the expected N400 and additional negativities. Determiner number mismatches elicited early anterior negativities, N400s and P600s. Verb number mismatches elicited biphasic N400-P600 patterns. However, pronoun + verb liaison mismatches yielded this pattern only in the plural, while consonant-final changes did so in the singular and the plural. Furthermore, an additional sustained frontal negativity was observed in two of the four verb mismatch conditions: plural liaison and singular consonant-final forms. This study highlights the different contributions of number cues in oral language processing and is the first to investigate whether auditory-visual mismatches can elicit errors reminiscent of outright grammatical errors. Our results emphasize that neurocognitive mechanisms underlying number agreement in French are modulated by the type of cue that is used to identify auditory-visual mismatches.

Survival in a fast-changing environment requires animals not only to detect unexpected sensory events, but also to react. In humans, these salient sensory events generate large electrocortical responses, which have been traditionally interpreted within the sensory domain. Here we describe a basic physiological mechanism coupling saliency-related cortical responses with motor output. In four experiments conducted on 70 healthy participants, we show that salient substartle sensory stimuli modulate isometric force exertion by human participants, and that this modulation is tightly coupled with electrocortical activity elicited by the same stimuli. We obtained four main results. First, the force modulation follows a complex triphasic pattern consisting of alternating decreases and increases of force, time-locked to stimulus onset. Second, this modulation occurs regardless of the sensory modality of the eliciting stimulus. Third, the magnitude of the force modulation is predicted by the amplitude of the electrocortical activity elicited by the same stimuli. Fourth, both neural and motor effects are not reflexive but depend on contextual factors. Together, these results indicate that sudden environmental stimuli have an immediate effect on motor processing , through a tight corticomuscular coupling. These observations suggest that saliency detection is not merely perceptive but reactive, preparing the animal for subsequent appropriate actions.

Studies regarding compound word processing have centred on Noun–noun words, which exhibit endocentricity. Nevertheless, other compound types, such as Spanish Verb–noun compounds, exhibit morphological particularities such as exocentricity, verb argument structure, and metaphorical features, increasing the attributes that may influence compound processing. We analysed whether these traits influenced Spanish Verb–noun compound processing. A lexical decision task was administrated with electroencephalogram (EEG) recording. Following differences in argument structure and metaphorical traits, three compound types were presented: Agentives, Locatives, and Metaphoricals. Locatives were responded worse and slower than Agentives. Metaphoricals elicited increases in the P300 and P600-like components. Thus, verb argument structure and metaphorical processes influence Spanish Verb–noun compound processing. Similarly to endocentric English Noun–noun compounds, processing Spanish Verb–noun compounds involves specific conceptual operations. These conceptual combinations appear to be determined by the projection of verb argument structure and the mapping and assignation of thematic roles.

The purpose of this document is to help individuals use the "Essential Motor Cortex Signal Processing MATLAB Toolbox". The toolbox implements various methods for three major aspects of investigating human motor cortex from Neuroscience view point: (1) ERP estimation and quantication, (2) Cortical Functional Connectivity analysis and (3) EMG quantication. The toolbox { which is distributed under the terms of the GNU GENERAL PUBLIC LICENSE as a set of MATLAB routines { can be downloaded directly at the address:
http://oset.ir/category.php?dir=Tools

or from the public repository on GitHub, at address below:
https://github.com/EsiSeraj/ERP Connectivity EMG Analysis

The purpose of this toolbox is threefold: 1. Extract the event-related-potential (ERP) from preprocessed cerebral signals (i.e. EEG, MEG, etc.), identify and then quantify the event-related synchronization/desynchronization (ERS/ERD) events. Both time-course dynamics and time-frequency (TF) analyzes are included. 2. Measure, quantify and demonstrate the cortical functional connectivity (CFC) across scalp electrodes. These set of functions can also be applied to various types of cerebral signals (i.e. electric and magnetic). 3. Quantify electromyogram (EMG) recorded from active muscles during performing motor tasks.

Social cognition might play a critical role in language acquisition and comprehension, as mindreading may be necessary to infer the intended meaning of linguistic expressions uttered by communicative partners. In three electrophysiological experiments, we explored the interplay between belief attribution and language comprehension of 14-month-old infants. First, we replicated our earlier finding: infants produced an N400 effect to correctly labelled objects when the labels did not match a communicative partner's beliefs about the referents. Second, we observed no N400 when we replaced the object with another category member. Third, when we named the objects incorrectly for infants, but congruently with the partner's false belief, we observed large N400 responses, suggesting that infants retained their own perspective in addition to that of the partner. We thus interpret the observed social N400 effect as a communicational expectancy indicator because it was contingent not on the attribution of false beliefs but on semantic expectations by both the self and the communicative partner. Additional exploratory analyses revealed an early, frontal, positive-going electrophysiological response in all three experiments, which was contingent on infants' computing the comprehension of the social partner based on attributed beliefs.

"Visual integration between target and irrelevant features leads to effects of irrelevant feature congruency (Stroop) or variation (Garner) on classification response performance. In a factorial design, Stroop and Garner effects were obtained on response times and error rates, and their correlates in brain activity were observed in event-related potentials (ERP). Stroop effects were manifested in ERP amplitude at the latencies of the N1 and N2 components, starting about 170 ms after stimulus onset. Garner effects were observed in the amplitude of the rising part of the P3 component, starting about 330 ms after stimulus onset. The difference in time course between Stroop and Garner effects is in accordance with the view that both are produced by different mechanisms, the former sensitive to interference within presentations and the latter to interference between presentations.
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Emotional information significantly affects cognitive processes, as proved by research in the past decades. Recently, emotional effects on language comprehension and, particularly, syntactic processing, have been reported. However, more research is needed, as this is yet very scarce. The present paper focuses on the effects of emotion-laden linguistic material (words) on subsequent morphosyntactic processing, by using Event-Related brain Potentials (ERP). The main aim of this paper is to clarify whether the effects previously reported remain when positive, negative and neutral stimuli are equated in arousal levels and whether they remain long-lasting. In addition, we aimed at testing whether these effects vary as a function of the task performed with the emotion-laden words, to assess their robustness across variations in attention and cognitive load during the processing of the emotional words. In this regard, two different tasks were performed: a reading aloud (RA) task, where participants simply read aloud the words, written in black on white background, and an Emotional Stroop (ES) task, where participants named the colors in which the emotional words were shown. After these words, neutral sentences followed, that had to be evaluated for grammaticality while recording ERPs (50% containing a morphosyntactic anomaly). ERP analyses showed main effects of valence across tasks on the two components reflecting morphosyntactic processing: The Left Anterior Negativity (LAN) is increased by previous emotional words (more by negative than positive) relative to neutral ones, while the P600 is similarly decreased. No interactions between task and valence were found. As a result, an emotion-laden word preceding a sentence can modulate the syntactic processing of the latter, independently of the arousal and processing conditions of the emotional word.

First language (L1) attrition in adulthood offers new insight on neuroplasticity and the role of language experience in shaping neurocognitive responses to language. Attriters are multilinguals for whom advancing L2 proficiency comes at the cost of the L1, as they experience a shift in exposure and dominance (e.g., due to immigration). To date, the neurocognitive mechanisms underlying L1 attrition are largely unexplored. Using event-related potentials (ERPs), we examined L1-Italian grammatical processing in 24 attriters and 30 Italian native-controls. We assessed whether (a) attriters differed from non-attriting native speakers in their online detection and re-analysis/repair of number agreement violations, and whether (b) differences in processing were modulated by L1-proficiency. To test both local and non-local agreement violations, we manipulated agreement between three inflected constituents and examined ERP responses on two of these (subject, verb, modifier). Our findings revealed group differences in amplitude, scalp distribution, and duration of LAN/N400 + P600 effects. We discuss these differences as reflecting influence of attriters' L2-English, as well as shallower online sentence repair processes than in non-attriting native speakers. ERP responses were also predicted by L1-Italian proficiency scores, with smaller N400/P600 amplitudes in lower proficiency individuals. Proficiency only modulated P600 amplitude between 650 and 900 ms, whereas the late P600 (beyond 900 ms) depended on group membership and amount of L1 exposure within attriters. Our study is the first to show qualitative and quantitative differences in ERP responses in attriters compared to non-attriting native speakers. Our results also emphasize that proficiency predicts language processing profiles, even in native-speakers, and that the P600 should not be considered a monolithic component.

Objective: Poor weight management may relate to a reduction in neurobehavioural control over food intake and heightened reactivity of the brain’s neural reward pathways. Here we explore the neurophysiology of food-related visual cue processing in weight reduced and weight relapsed women by assessing differences in cortical arousal and attentional processing using a food-Stroop paradigm. Methods: 51 women were recruited into 4 groups: reduced-weight participants (RED, n = 14) compared to BMI matched low-weight controls (LW-CTL, n = 18); and weight relapsed participants (REL, n = 10) compared to BMI matched high-weight controls (HW-CTL, n = 9). Eating behaviour and body image questionnaires were completed. Two Stroop tasks (one containing food images, the other containing neutral images) were completed with record of electroencephalography (EEG). Results: Differences in cortical arousal were found in RED versus LW-CTL women, and were seen during food task execution only. Compared to their controls, RED women exhibited lower relative delta band power (p = 0.01) and higher relative beta band power (p = 0.01) over the right frontal cortex (F4). Within the RED group, delta band oscillations correlated positively with self-reported habitual fat intake and with body shape dissatisfaction. Conclusions: As compared to women matched for phenotype but with no history of weight reduction, reduced-overweight/obese women show increased neurobehavioural control over external food cues and the inhibition of reward-orientated feeding responses. Insight into these self-regulatory mechanisms which attenuate food cue saliency may aid in the development of cognitive remediation therapies which facilitate long-term weight loss.