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Speech discrimination is used by audiologists in diagnosing and determining treatment for hearing loss patients. Usually, assessing speech discrimination requires subjective responses. Using electroencephalography (EEG), a method that is based on event-related potentials (ERPs), could provide objective speech discrimination. In this work we proposed a visual-ERP-based method to assess speech discrimination using pictures that represent word meaning. The proposed method was implemented with three strategies, each with different number of pictures and test sequences. Machine learning was adopted to classify between the task conditions based on features that were extracted from EEG signals. The results from the proposed method were compared to that of a similar visual-ERP-based method using letters and a method that is based on the auditory mismatch negativity (MMN) component. The P3 component and the late positive potential (LPP) component were observed in the two visual-ERP-based methods while MMN was observed during the MMN-based method. A total of two out of three strategies of the proposed method, along with the MMN-based method, achieved approximately 80% average classification accuracy by a combination of support vector machine (SVM) and common spatial pattern (CSP). Potentially, these methods could serve as a pre-screening tool to make speech discrimination assessment more accessible, particularly in areas with a shortage of audiologists.

Several neurological processes are undergoing on a conscious and subconscious level every time a consumer likes or dislikes a product. There is presently significant research in Consumer Neuroscience based on consumer behaviour and understanding of these processes. In this study, we have used Electroencephalography (EEG) and Event-Related Potentials (ERP) to capture consumer responses to highly familiar product images. EEG analysed from the 27 participants was used to extract P1, N1, P300, N400 and Late Posterior components. The analysis showed that the early ERP components viz., P1, N1 and P300 can differentiate between consumer liking and disliking of products. In contrast, the late ERP components N400 and Late Posterior components could not differentiate in the highly familiar product category. The results indicate that after continuous exposure, consumer preference towards highly-familiar products occurs as a part of automatic, unconscious mental processes irrespective of the product properties. Further research in this direction can test for the transference of consumer preference: from a conscious mental process to a subconscious mental process due to excessive and continuous product exposure and marketing repetition. Our study demonstrates that consumer behaviour in response to highly-familiar products can be classified using early ERP components only.

Agar dapat berinteraksi secara efisien terhadap banyaknya informasi sensori, otak memiliki strategi heuristis yang dapat menyaring informasi sekaligus mengarahkan atensi ketika muncul informasi yang penting dan krusial. Penelitian tentang otak telah mengungkapkan salah satu penanda atas sistem tersebut, yang disebut sebagai Mismatch Negativity (MMN). MMN merupakan salah satu komponen dari Event-Related brain Potentials (ERP) yang diasosiasikan dengan penanda sistem pendeteksi perubahan dan pelanggaran tiba-tiba terhadap aturan abstrak dari stimulus suara, dan dapat digunakan sebagai indikator objektif mengenai akurasi diskriminasi suara, sensori memori, maupun proses praatensi. Komponen MMN muncul sebagai gelombang negatif yang terpicu oleh stimulus yang menyimpang dari keteraturan. Metode MMN telah banyak digunakan dalam berbagai bidang penelitian hingga konteks klinis. MMN juga merupakan metode yang sangat bermanfaat untuk menyelidiki mekanisme pemrosesan kognitif pada populasi yang memiliki kesulitan untuk mengikuti prosedur eksperimen, misalnya pada anak-anak, atau pasien klinis karena sifatnya yang otomatis dan tidak membutuhkan atensi. Artikel ini bertujuan untuk memberikan pengenalan mengenai konsep dan prinsip dasar dalam MMN, paradigma eksperimen, hingga contoh aplikasi, dan potensi penelitian yang dapat dilakukan menggunakan metode ini.

Dynamic and temporal facets of the various constructs that comprise motivation remain to be explored. Here, we adapted the Effort Expenditure for Reward Task, a well-known laboratory task used to evaluate motivation, to study the event-related potentials associated with reward processing. The Stimulus Preceding Negativity (SPN) and the P300 were utilized as motivation indicators with high density electroencephalography. The SPN was found to be more negative for difficult choices compared to easy choices, suggesting a greater level of motivation, at a neurophysiological level. The insula, a structure previously associated with both effort discounting and prediction error, was concomitantly activated during the generation of the SPN. Processing a gain significantly altered the amplitude of the P300 compared to an absence of gain, particularly on centroparietal electrodes. One of the generators of the P300 was located on the vmPFC, a cerebral structure involved in the choice between two positive results and their predictions, during loss processing. Both the SPN and the P300 appear to be reliable neural markers of motivation. We postulate that the SPN represents the strength of the motivational level, while the P300 represents the impact of motivation on updating memories of the feedback.

This review is aimed at exploring the usefulness of measuring event-related potential (ERP) in cognitive tests and discusses several applications of the ERP technique. Analysis of ERP components is one of the most informative dynamic methods of investigation and monitoring of information processing stages in the human brain. Amplitude and latency of ERP components at specified topographies reflect early sensory perception processes and higher level processing including attention, cortical inhibition, memory update, error monitoring, and other cognitive activities. ERPs provide a method of studying cognitive processes in typical subjects, as well as a sensitive instrument to assess differences in individuals with neuro- and psychopathologies. Despite significant advances in functional neuroimaging, the ERP measure still represents an important tool for brain research in psychiatry, as many psychiatric diseases correlate with certain altered patterns of ERPs. Such ERP alterations can serve as valid biological markers for functional diagnostic or for better understanding of the cognitive functions which are disturbed in psychiatric disorders. Application of ERPs in psychiatric treatment research is an approach aimed at validation of specific ERP measures as sensitive functional outcomes of experimental neuromodulation interventions such as rTMS and neurofeedback. Also discussed are additional aspects of ERP usefulness in psychiatry research and treatment.

Objectives Language functional magnetic resonance imaging (fMRI) represents the clinical standard for language lateralization assessment in presurgical epilepsy evaluation, but still many patients experience postoperative language deficits. Event-related potentials (ERPs), especially the negative component around and after 400 ms, are related to language processing and could therefore represent a complementary method of language lateralization assessment. Methods Scalp EEG was recorded from 64 locations in 36 epilepsy patients and 37 controls during three visually presented language tasks: A short-term language memory task (differentiation memorized vs. unknown words), a phonological task (detection of rhymes in word pairs), and a semantic decision task (differentiation words vs. pseudowords). ERPs were analyzed in the 300 ms–800 ms epoch. Language fMRI was routinely obtained in patients. Results ERPs were significantly more negative over the left compared to the right hemisphere in all three tasks in patients and controls. Laterality indices showed highest concordance with fMRI for the Word/Pseudoword Task. Conclusions ERPs of language processing were lateralized to the left hemisphere in the majority of epilepsy patients and controls. In patients, single-subject laterality indices showed high concordance with fMRI results. Significance Results indicate that scalp-derived ERPs are a promising tool to investigate lateralization of language function in epilepsy patients.

The present study is designed to establish how lexical frequency of Russian words influences the acoustic mismatch negativity (MMN) latency and amplitude. The event related potentials (ERP) were recorded according to the multi-deviant passive odd-ball paradigm by using Russian words with different lexical frequencies and pseudowords. We found that the high-frequency words presentation led to a significantly more pronounced MMN response relative to the low-frequency one. The high-frequency words also evoked an earlier response, indicating more rapid access to a frequently used lexical entry. We suggest that a more pronounced amplitude and an earlier latency of acoustic MMN of high-frequency versus low-frequency items is a result of the word memory traces activation as more strongly connected assemblies of neurons. The MMN amplitude and latency for words were partly matched with the MMN for pseudowords (the analog of high-frequency word evoked the most pronounced response and the analog of low-frequency word evoked the weakest response), but the MMN amplitude and latency for pseudowords were significantly more pronounced and longer. We interpret this as evidence that processing of meaningless or unknown items is longer and their discrimination is more late and inaccurate than the discrimination of meaningful and frequently activated language elements.

Objective The electrophysiological characteristics may serve as valuable biomarkers for the genetic vulnerability underlying alcoholism. The purpose of this study was to evaluate the potential associations between single nucleotide polymorphisms (SNPs) located in the SGIP1 gene and the theta ERP quantitative traits. Method The theta band (4–7 Hz) visual ERP occurring in the P300 response in the resting EEG were examined to explore the electrophysiological effects of alcohol on the brain in five regions: frontal, central, parietal, temporal and occipital in patients with alcohol addiction. In addition, we tested the potential associations between single nucleotide polymorphisms (SNPs) located in the SGIP1 gene and ERP quantitative traits. Results We found that the amplitude of the auditory P300 response differed considerably among groups of alcoholics in the frontal, central and temporal areas of the brain and it was lower in the studied brain regions in alcoholics in comparison to non-alcoholics. However, among subjects in the young adult group (GR-1) there was no statistical difference in amplitude of P300 response with control subjects in all studied brain regions in comparison with non-alcoholics. Moreover, we revealed that SNP rs10889635 had a significant effect on P300 amplitude in the central and temporal regions. The reduced P300 amplitude was in AA carriers in comparison to both carriers of GG and GA alleles. Conclusions The present study demonstrated a possible association of target P300 evoked theta and of alcohol dependence with SNPs from the gene SGIP1 in the region of rs10889635, but further studies are required.

Working memory used for a goal-directed behavior has limited capacity. In this article, we examined what the specific function of the working memory capacity as the controlled attention function was. In addition, we discussed how working memory capacity affected the everyday situations in terms of the mind wandering. In the study using event-related potential (ERP), the analysis examined relationship between individual difference in working memory capacity and ERP component involved mind wandering. The amplitude of ERP component involved mind wandering for low-span group has smaller than high-span group. This result suggested possibility that many mind wandering occurred in low-span group during the tasks. Finally, we discussed further research and educational aspect based on the relationship between working memory capacity and attention., 「何かをするために使われる記憶」であるワーキングメモリには，制限された容量が存在する。本論文では，注意制御機能としてのワーキングメモリ容量の具体的な機能は何なのか検証した。また，この機能が日常場面にどのように関わるのか，マインドワンダリングという観点から考察し，事象関連電位を用いた研究から，ワーキングメモリ容量の個人差とマインドワンダリングに関連した事象関連電位成分を検証した。ワーキングメモリ容量低群ほど，マインドワンダリングが生じることで事象関連電位の振幅が減衰した可能性を示唆した。最後に，ワーキングメモリ容量と注意の関係を踏まえた教育的場面への応用について論じ，今後の研究可能性を考察した。

A key component in correcting misinformation is the removal of incorrect information and subsequent updating of the associated mental model. Whilst a body of behavioural research has examined this phenomenon, neuroscientific research in the area is lacking. The current study aimed to examine differences in three event-related potential (ERP) components associated with memory encoding and updating: a left-frontal positivity, the feedback-related negativity, and the parietal P3b. Participants were 39 young adults who were presented with 70 statements that they were required to judge as myths or facts whilst electroencephalographic data were recorded, and then again after a one-week retention interval. Differences between ERP component amplitudes of correctly and incorrectly classified statements were analysed when feedback was presented to participants during testing period 1. Behavioural performance improved across testing periods, but frequentist and Bayesian analyses found no differences between ERP amplitudes elicited by correct or incorrect feedback. It is likely that no effect was observed due to memory removal and updating processes being variable in terms of onset and/or duration. Future research could consider employing analyses that do not include a temporal dimension or adjust for latency variability to investigate if any reliable non-time-locked electrophysiological modulations occur during misinformation correction.

Ketamine is a non-competitive N-Methyl-D-Aspartate (NMDA) receptor antagonist whose effect in subanesthetic doses has been studied for chronic pain and mood disorders treatment. It has been proposed that ketamine could change the perception of nociceptive stimuli by modulating the cortical connectivity and altering the top-down mechanisms that control conscious pain perception. As this is a strictly central effect, it would be relevant to provide fresh insight into ketamine's effect on cortical response to external stimuli. Event-related potentials (ERPs) reflect the combined synchronic activity of postsynaptic potentials of many cortical pyramidal neurons similarly oriented, being a well-established technique to study cortical responses to sensory input. Therefore, the aim of this study was to examine the current evidence of subanesthetic ketamine doses on patterns of cortical activity based on ERPs in healthy subjects. To answer the question whether ERPs could be potential markers of the cortical effects of ketamine, we conducted a systematic review of ketamine's effect on ERPs after single and repeated doses. We have searched PubMed, EMBASE and Cochrane Databases and pre-selected 141 articles, 18 of which met the inclusion criteria. Our findings suggest that after ketamine administration some ERP parameters are reduced (reduced N2, P2, and P3 amplitudes, PN and MMN) while others remain stable or are even increased (P50 reduction, PPI, P1, and N1 amplitudes). The current understanding of these effects is that ketamine alters the perceived contrast between distinct visual and auditory stimuli. The analgesic effect of ketamine might also be influenced by a decreased affective discrimination of sensorial information, a finding from studies using ketamine as a model for schizophrenia, but that can give an important hint not only for the treatment of mood disorders, but also to treat pain and ketamine abuse.

Tinnitus related distress corresponds to different degrees of attention paid to the tinnitus. Shifting attention to a signal other than the tinnitus is therefore particularly difficult for patients with high tinnitus related distress. As attention effects on Event Related Potentials (ERP) have been shown this should be reflected in ERP measurements (N100, phase locking). In order to prove this hypothesis single sweep ERP recordings were obtained in 41 tinnitus patients as well as 10 control subjects during a period of time when attention was shifted to a tone (attended) and during a second phase (unattended) when they did not focus attention to the tone. Whereas tinnitus patients with low distress showed a significant reduction in both N100 amplitude and phase locking when comparing the attended and unattended measurement condition a group of patients with high tinnitus related distress did not show such ERP alterations. Using single sweep ERP measurements the results of our study show, that attention in high tinnitus related distress patients is captured by their tinnitus significantly more than in low distress patients. Furthermore our results provide the basis for future neurofeedback based tinnitus therapies aiming at maximizing the ability to shift attention away from the tinnitus. peerReviewed

In this paper, we address the problem of quantifying the commonly observed disorganization of the stereotyped wave form of the ERP associated with the P300 component in patients with Alzheimer's disease. To that extent, we propose two new measures of complexity which relate the spectral content of the signal with its temporal waveform: the spectral matching coefficient and the spectral matching entropy. We show by means of experiments that those measures effectively measure complexity and are related to the shape in an intuitive way. Those indexes are compared with commonly used measures of complexity when comparing AD patients against age-matched healthy controls. The results indicate that AD ERP signals are, indeed, more complex in the shape than that of controls, and this result is evidenced mainly by means of our new measures which have a better performance compared to similar ones. Finally, we try to explain this increase in complexity in light of the communication through coherence hypothesis framework, relating commonly found changes in the EEG with our own results.

Humans are fast and accurate in categorizing complex natural images. It is, however, unclear what features of visual information are exploited by brain to perceive the images with such speed and accuracy. It has been shown that low-level contrast statistics of natural scenes can explain the variance of amplitude of event-related potentials (ERP) in response to rapidly presented images. In this study, we investigated the effect of these statistics on frequency content of ERPs. We recorded ERPs from human subjects, while they viewed natural images each presented for 70 ms. Our results showed that Weibull contrast statistics, as a biologically plausible model, explained the variance of ERPs the best, compared to other image statistics that we assessed. Our time-frequency analysis revealed a significant correlation between these statistics and ERPs’ power within theta frequency band (~3-7 Hz). This is interesting, as theta band is believed to be involved in context updating and semantic encoding. This correlation became significant at ~110 ms after stimulus onset, and peaked at 138 ms. Our results show that not only the amplitude but also the frequency of neural responses can be modulated with low-level contrast statistics of natural images and highlights their potential role in scene perception.

Objective In tasks involving hierarchical stimuli, young subjects typically show faster RTs and higher accuracy rates in discriminating target stimuli at the global level than at the local level. This pattern of performance is called the global precedence effect (GPE). As individuals age, this patterns shifts to a local precedence effect (LPE). The purpose of this study was to determine whether the decline in GPE in older adults may be due to impairment of grouping processes. Method The authors recorded event-related potentials (ERP) while young and elderly subjects performed a global/local task in response to hierarchical stimuli, and they focused on the P300 component as an index of grouping processes. Results Compared to young subjects, elderly individuals showed a lower rate of correct discrimination in global processing conditions, but a higher rate of correct responses in local processing conditions, confirming a shift from a GPE to a LPE during aging. Interestingly, the P300 amplitude increased selectively during global processing in young adults but was not modulated by processing level in older participants. By contrast, the modulation of the early component N2 as a function of precedence level remained preserved in older subjects. Conclusion The results suggest that the precedence level may depend on early processes that are unaffected during aging. This may explain the preservation of local precedence effect in elderly individuals. However, global processing may depend on extra attentional processing occurring at later stages. The alteration of later processing may explain the decline in global precedence during aging. (PsycINFO Database Record

Event-related potential data can be used to index perceptual and cognitive operations. However, they are typically high-dimensional and noisy. This study examines the original raw data and six feature-extraction methods as a pre-processing step before classification. Four traditionally used feature-extraction methods were considered: principal component analysis, independent component analysis, auto-regression, and wavelets. We add to these a less well-known method called interval feature extraction. It overproduces features from the ERP signal and then eliminates irrelevant and redundant features by the fast correlation-based filter. To make the comparisons fair, the other feature-extraction methods were also run with the filter. An experiment on two EEG datasets (four classification scenarios) was carried out to examine the classification accuracy of four classifiers on the extracted features: support vector machines with linear and perceptron kernel, the nearest neighbour classifier and the random forest ensemble method. The interval features led to the best classification accuracy in most of the configurations, specifically when used with the Random Forest classifier ensemble.

Event related potentials (ERP) to visually presented linguistic stimuli were examined using a lexical-decision task and an oddball paradigm. Stimuli were presented to the central, right or left visual fields (CVF, RVF and LVF) and generated ERP with very clear N100-P300 components. The question addressed was whether there is ERP evidence for left hemisphere (LH) superiority in linguistic discrimination as reported behaviorally. Nineteen young, right-handed male subjects participated. The main factor influencing the latency and amplitude of N100 was that of contralateral versus ipsilateral stimulation. Shorter N100 latency and larger amplitude were recorded over the hemisphere contralateral to the visual field stimulated. In contrast, the factors influencing the P300 parameters were the visual field stimulated and the hemisphere over which the ERP was recorded. P300 amplitude was significantly larger and P300 latency significantly shorter over the LH than over the RH. Significantly shorter P300 latency and larger peak amplitude were found for RVF than for LVF stimulation.

The main goal of this event-related potentials (ERPs) study was to assess the effects of stimulations in Stroop task in brain activities of patients with different degrees of depression. Eighteen patients (10 males, with the mean age [Formula: see text]) were asked to fill out Beck’s depression questionnaire. Electroencephalographic (EEG) signals of subjects were recorded in three channels (Pz, Cz, and Fz) during Stroop test. This test entailed 360 stimulations, which included 120 congruent, 120 incongruent, and 120 neutral stimulations. To analyze the data, 18 time features in each type of stimulus were extracted from the ERP components and the optimal features were selected. The correlation between the subjects’ scores in Beck’s depression questionnaires and the extracted time features in each recording channel was calculated in order to select the best features. Total area, and peak-to-peak time window in the Cz channel in both the congruent and incongruent stimulus showed significant correlation with Beck scores, with [Formula: see text], [Formula: see text] and [Formula: see text], [Formula: see text], respectively. Consequently, given the correlation between time features and the subjects’ Beck scores with different degrees of depression, it can be interpreted that in case of growth in degrees of depression, stimulations involving congruent images would produce more challenging interferences for the patients compared to incongruent stimulations which can be more effective in diagnosing the level of disorder.

ERP is the measured brain response with electroencephalography that is direct result of a specific event. First cognitive components were discovered in the 1960s, and currently ERP is one of the most widely used methods in cognitive neuroscience research. The studies of ERP for pediatrics make advance with developmental disorders. It is possible for ERP to stimulate with suitable tasks for each disorder. Patients with ADHD have problems with executive functions, especially inhibitory function. NoGo potentials indicate inhibitory function. In ADHD children, the latency of NoGo potentials was prolonged. The patients of autistic spectrum disorder (ASD) have problems with sociality, communication and sympathies. The face related potentials were abnormal for ASD children, and they had different response during the pain stimulation against other people. Dyslexic patients have problems of phonological processing. The mismatch negativity during phonologic task was decreased in dyslexic children. N400 is elicited in a sentence reading task with semantically appropriate words, and auditory N400 was decreased in dyslexic children. Thus, ERP may be one of useful methods as diagnostic biomarker. Recently, simultaneous method with fMRI or fNIRS, and the combination of analysis with LORETA and DCM are reported, further development with research of ERP will be favorable.

The study aims to explore the significance of event-related potentials (ERPs) and event-related brain oscillations (EROs) (delta, theta, and alpha power) in response to emotional face during 180-250 poststimulus time interval. Twenty-one adults looked at emotional (sad, happy, fearful) or neutral faces. The results demonstrated that the emotional face elicited a negative peak at approximately 230 ms (N230). Moreover EEG measures showed that motivational significance of face (stimulus type) can modulate the amplitude of EEG, especially for theta and delta. Regression analysis showed that theta oscillations mainly effect as oscillation activity at the N2 latency. Thus, this frequency band variation could represent a complex set of cognitive processes, whereby selective attention becomes focused on an emotional relevant stimulus.

International audience; The size and font of target words were manipulated in a masked repetition priming paradigm with ERP recordings. Repetition priming effects were found in four ERP components: the N/P150, N250, P325, and N400. Neither a change in font nor a change in size across prime and target were found to affect repetition priming in the N250, P325, and N400 components. Changing font was, however, found to affect repetition priming in the N/P150 component, while the interaction between repetition priming and size was not significant in this component. These results confirm our interpretation of the N/P150 as a component sensitive to feature-level processing, and suggest that the type of prelexical and lexical processing reflected in the N250, P325, and N400 components is performed on representations that are invariant to changes in both font and size.

Contains fulltext : 99512.pdf (Publisher’s version ) (Open Access) We present MINEMO (Minimal Information for Neural ElectroMagnetic Ontologies), a checklist for the description of event-related potentials (ERP) studies. MINEMO extends MINI (Minimal Information for Neuroscience Investigations) to the ERP domain. Checklist terms are explicated in NEMO, a formal ontology that is designed to support ERP data sharing and integration. MINEMO is also linked to an ERP database and web application (the NEMO portal). Users upload their data and enter MINEMO information through the portal. The database then stores these entries in RDF (Resource Description Framework), along with summary metrics, i.e., spatial and temporal metadata. Together these spatial, temporal, and functional metadata provide a complete description of ERP data and the context in which these data were acquired. The RDF files then serve as inputs to ontology-based labeling and meta-analysis. Our ultimate goal is to represent ERPs using a rich semantic structure, so results can be queried at multiple levels, to stimulate novel hypotheses and to promote a high-level, integrative account of ERP results across diverse study methods and paradigms.

We present MINEMO (Minimal Information for Neural ElectroMagnetic Ontologies), a checklist for the description of event-related potentials (ERP) studies. MINEMO extends MINI (Minimal Information for Neuroscience Investigations) to the ERP domain. Checklist terms are explicated in NEMO, a formal ontology that is designed to support ERP data sharing and integration. MINEMO is also linked to an ERP database and web application (the NEMO portal). Users upload their data and enter MINEMO information through the portal. The database then stores these entries in RDF (Resource Description Framework), along with summary metrics, i.e., spatial and temporal metadata. Together these spatial, temporal, and functional metadata provide a complete description of ERP data and the context in which these data were acquired. The RDF files then serve as inputs to ontology-based labeling and meta-analysis. Our ultimate goal is to represent ERPs using a rich semantic structure, so results can be queried at multiple levels, to stimulate novel hypotheses and to promote a high-level, integrative account of ERP results across diverse study methods and paradigms.

We studied the brain's reactions to deviations in the duration of a stop consonant using event-related potentials in an oddball paradigm. A naturally produced nonsense word was used as a frequent standard stimulus which differed from two infrequently presented deviant stimuli only by the duration of the silence period inside the stop, making the consonant sound longer. Evoked responses to the deviant stimuli showed sharply rising negativity after the unexpected prolongation of the silence and a later negativity, the duration of which was related to the timing of the beginning of the second part of the deviant sound. This later negativity is, at least partly, elicited by a mismatch process to the omission of a sound at the expected latency.

The effects of age, stimulus modality and event probability on event-related potentials (ERP) were studied in 12 young and 12 elderly healthy subjects. The ERP were recorded from 15 electrodes referred to linked ears. Results showed that both amplitude and latency of the P300 component are affected by aging. Study of the latency of the earlier ERP components in the two age groups revealed that the P300 delay was not imputable to a delay of the earlier components. P300 amplitude and latency were also affected by event probability and stimulus modality: infrequent stimulus involved higher and later P300, but this effect was more pronounced in the young than in the old group; higher and later P300 were also recorded during the visual task compared to the auditory. Topographical repartition of the brain wave revealed a predominance of the central sites (Fz, Cz, Pz). The findings are discussed in relation to the sensitivity of the ERP assessment procedures in age related modifications of information processing.

International audience; Aims of the study A brain-Computer Interface aims at restoring communication and control in severely disabled people by identification and classification of EEG features such as Event Related Potentials (ERPs). The aim of this study is to compare different EEG recording modalities for extraction of ERPs. The first comparison evaluates the performance of six disc electrodes with that of the Emotiv headset, while the second evaluates three different electrode types (disc, needle, and large squared electrode). Material and methods Ten healthy volunteers gave informed consent and were randomized to try the traditional EEG system (6 disc electrodes with gel and skin preparation) or the Emotiv headset first. Together with the six disc electrodes, a needle and a square electrode of larger surface were simultaneously recording near lead Cz. Each modality was evaluated over three sessions of auditory P300 separated by one hour. Results No statically significant effect was found for the electrode type, nor was the interaction between electrode type and session number. There was no statistically significant difference of performance between the Emotiv and the six traditional EEG disc electrodes, although there was a trend showing worse performance of the Emotive headset. However, the Modality-Session interaction was highly significant (p

The present study was aimed at identifying potential behavioral and neural correlates of emotional intelligence (EI) by using scalp-recorded Event-Related Potentials (ERPs). EI levels were defined according to both self-report questionnaire and a performance-based test. We identified ERP correlates of emotional processing by comparing ERPs elicited in trials using pleasant, neutral and unpleasant pictures. The effects of these emotion-inducing pictures were then compared across groups with low and high EI levels. Behavioral results revealed a significant valence×EI group interaction effect since valence ratings were lower for unpleasant pictures and higher for pleasant pictures in the high EI group compared with the low EI group. The groups did not differ with respect to neutral picture ratings. The ERP results indicate that participants with high EI exhibited significantly greater mean amplitudes of the P2 (200-300ms post-stimulus) and P3 (310-450ms post-stimulus) ERP components in response to emotional and neutral pictures, at posterior-parietal as well as at frontal scalp locations. This may suggest greater recruitment of resources to process all emotional and non-emotional stimuli at early and late processing stages among individuals with higher EI. The present study also underscores the usefulness of ERP methodology as a sensitive measure for the study of emotional stimuli processing in the research field of EI.

ObjectivesTo compare the event-related potentials (ERPs) and brain topographic maps characteristic and change in normal controls and subjective tinnitus patients before and after repetitive transcranial magnetic stimulation (rTMS) treatment.Methods and participantsThe ERPs and brain topographic maps elicited by target stimulus were compared before and after 1-week treatment with rTMS in 20 subjective tinnitus patients and 16 healthy controls.ResultsBefore rTMS, target stimulus elicited a larger N1 component than the standard stimuli (repeating sounds)in control group but not in tinnitus patients. Instead, the tinnitus group pre-treatment exhibited larger amplitude of N1 in response to standard stimuli than to deviant stimuli. Furthermore tinnitus patients had smaller mismatch negativity (MMN) and late discriminative negativity (LDN)component at Fz compared with the control group. After rTMS treatment, tinnitus patients showed increased N1 response to deviant stimuli and larger MMN and LDN compared with pre-treatment. The topographic maps for the tinnitus group before rTMS -treatment demonstrated global asymmetry between the left and right cerebral hemispheres with more negative activities in left side and more positive activities in right side. In contrast, the brain topographic maps for patients after rTMS-treatment and controls seem roughly symmetrical. The ERP amplitudes and brain topographic maps in post-treatment patient group showed no significant difference with those in controls.ConclusionsThe characterical changes in ERP and brain topographic maps in tinnitus patients maybe related with the electrophysiological mechanism of tinnitus induction and development. It can be used as an objective biomarker for the evaluation of auditory central in subjective tinnitus patients. These findings support the notion that rTMS treatment in tinnitus patients may exert a beneficial effect.

Tese de doutoramento em Psicologia (área de conhecimento em Psicologia Clínica), Language and communication abnormalities are a hallmark of both Williams Syndrome (WS) and Schizophrenia. Both disorders represent atypical developmental pathways, in which the complexity of the relationships between genes, brain, and behavior has been intriguing researchers for decades. On the one hand, WS represents a genetic disorder characterized by a submicroscopic deletion in chromosome 7. This syndrome was initially proposed as a paradigmatic example of cognitive dissociation and, in particular, of the independence of language from general cognition. On the other hand, Schizophrenia is characterized by a multiplicity of symptoms (e.g., hallucinations, delusions, thought disorder, flat affect), with genetic and environmental factors contributing to its onset. Dysfunction in language and emotional processing has been consistently reported in both disorders, contributing to deficits in social interactions. The studies described in this dissertation aimed at analyzing the electrophysiological correlates of language processing in both WS and Schizophrenia, in particular semantics and prosody. The event-related potentials (ERP) technique was chosen due to its temporal resolution that is ideal for the investigation of language. Study 1 explored the electrophysiological correlates of prosody processing in WS, comparing emotional intonations embedded in intelligible semantic information, and ‘pure prosody’ sentences. Abnormalities were found in N100, P200, and N300 components in WS individuals, when compared with typically developing controls. In particular, reduced N100 was observed for prosody sentences with semantic content but more negative N100 for pure prosody sentences, and more positive P200 for both pure prosody sentences and sentences with semantic content, in particular for happy intonations. These findings suggest abnormalities in early auditory processing, indicating a bottom-up contribution to the impairment in emotional prosody processing and comprehension. Also, the reduced N300 peak amplitude in individuals in WS at parietal electrodes and its enhancement at frontal electrodes may indicate abnormal electrophysiological response at the stage of evaluating the emotional significance of the auditory message. Study 2 analyzed the ERP correlates of semantic processing in WS. A set of sentences was presented auditorily, with half ending with an expected word, and half ending with an unexpected and implausible word. Abnormalities were found in early sensorial components (N100 and P200) in WS, although no differences between WS and a typically developing group were found for the N400 component (an index of semantic integration). Interestingly, more positive P600 amplitude was found for WS, suggesting difficulties in later integration processes. Study 3 aimed at characterizing the electrophysiological correlates of prosody processing in Schizophrenia, using the same experimental paradigm described in Study 2. Results showed sensory abnormality in processing auditory signal for all prosody types (reduced N100), as well as failure to extract emotion-specific information from the auditory signal (P200). Importantly, both types of abnormalities were found in sentences with semantic content only, suggesting topdown modulation of sensory-level and automatic processing of prosodic information. Study 4 aimed at investigating the effects of induced mood (neutral vs. positive vs. negative) on semantic processing in Schizophrenia. Data suggest differential access to semantic networks in this neuropsychiatric disorder, and abnormalities in the modulation of language processing by mood, as indexed by N400 amplitude to three types of sentence endings (expected words, unexpected words from the same semantic category as the expected exemplar, and unexpected words from a different semantic category of the expected exemplar), under neutral, positive, or negative mood. Differences were more pronounced under positive mood. Together, these ERP studies provide, for the first time, electrophysiological evidence for atypical prosody processing in both WS and Schizophrenia, and for abnormal interactions of mood and cognition in Schizophrenia. Also, they extend few previous ERP studies with WS on semantic processing, including, for the first time, participants with European Portuguese as native language. These findings are expected to contribute to a better understanding of language atypicalities in both disorders., Alterações da linguagem e da comunicação são uma característica central da Síndrome de Williams (SW) e da Esquizofrenia. Ambas constituem trajectórias desenvolvimentais atípicas, em que a complexidade inerente às relações entre genes, cérebro e comportamento tem intrigado investigadores há várias décadas. Por um lado, a SW representa uma perturbação genética caracterizada por uma delecção submicroscópica no cromossoma 7. Esta síndrome foi, inicialmente, proposta como um exemplo paradigmático de dissociação cognitiva e, em particular, de independência da linguagem em relação à cognição geral. Por outro lado, a Esquizofrenia é caracterizada por uma multiplicidade de sintomas (e.g., alucinações, delírios, perturbação do pensamento, embotamento afectivo), sendo o seu início influenciado por factores genéticos e ambientais. Alterações ao nível do processamento da linguagem e emocional têm sido consistentemente reportadas em ambas as perturbações, contribuindo para os défices verificados ao nível das interacções sociais. Os estudos descritos nesta Tese tiveram como objectivo a análise dos correlatos electrofisiológicos do processamento da linguagem na SW e na Esquizofrenia, em particular o processamento semântico e prosódico. A técnica de potenciais evocados (ERP) foi escolhida devido à sua resolução temporal, que é ideal para a investigação da linguagem. No Estudo 1 exploraram-se os correlatos electrofisiológicos do processamento da prosódia na SW, comparando prosódia emocional em frases com conteúdo semântico perceptível, com prosódia em frases transformadas sem conteúdo semântico perceptível. Os resultados apontaram para anormalidades nos componentes de onda N100, P200 e N300 em indivíduos com SW, quando comparados com um grupo com desenvolvimento normal. Em particular, observou-se uma reduzida amplitude do componente N100 para frases com entoação prosódica e conteúdo semântico inteligível, e uma amplitude mais negativa do mesmo componente para frases de prosódia “pura”. Ao mesmo tempo, a amplitude da P200 na SW foi mais positiva, em comparação com o grupo de desenvolvimento típico, quer para frases de prosódia “pura”, quer para frases com entoação prosódica e conteúdo semântico inteligível, e em particular para prosódia alegre. Estes resultados sugerem anomalias em fases precoces do processamento auditivo, indicando uma contribuição bottom-up para as alterações evidenciadas no processamento e compreensão da prosódia emocional na SW. Finalmente, a observação de uma redução da amplitude do componente N300 em eléctrodos parietais e o seu aumento em eléctrodos frontais poderá indicar anormalidades na resposta electrofisiológica associada à avaliação do significado emocional da mensagem acústica. O Estudo 2 analisou os correlatos electrofisiológicos do processamento semântico na SW. Um conjunto de frases foi apresentado auditivamente, metade delas terminando com uma palavra esperada e metade terminando com uma palavra inesperada e implausível. Os resultados revelaram anomalias em componentes sensoriais precoces (N100 e P200), apesar de não terem sido observadas diferenças entre a SW e um grupo com desenvolvimento típico no componente de onda N400 (um indicador de processos de integração semântica). Interessantemente, a amplitude do componente P600 foi mais positiva na SW, o que sugere dificuldades em processos de integração tardios. O Estudo 3 teve como objectivo a caracterização dos correlatos electrofisiológicos do processamento prosódico na Esquizofrenia, tendo como base o paradigma experimental descrito no Estudo 2. Os resultados sugerem anomalias sensoriais no processamento do sinal auditivo para todos os tipos de prosódia (redução da amplitude da N100), bem como dificuldades na extracção de informação emocional específica a partir do sinal auditivo (P200). Ambos os tipos de anomalias foram encontrados apenas para frases com conteúdo semântico, sugerindo uma modulação top-down do processamento sensorial e automático da informação prosódica. O objectivo do Estudo 4 foi investigar os efeitos do humor induzido (neutro vs. positivo vs. negativo) no processamento semântico na Esquizofrenia. Os dados obtidos sugerem um acesso diferencial às redes semânticas nesta perturbação, bem como anomalias na modulação do processamento linguístico pelo estado de humor, tal como evidenciado pela amplitude do componente de onda N400 para três tipos de finais de frase (palavras esperadas, palavras não esperadas da mesma categoria semântica da palavra esperada, palavras não esperadas de uma categoria semântica diferente da da palavra esperada), em três tipo de humor (neutro vs. positivo vs. negativo). Estas diferenças foram mais pronunciadas na condição de humor positivo. Em conjunto, estes estudos ERP apresentaram, pela primeira vez, evidência electrofisiológica para o processamento atípico da prosódia emocional quer na SW quer na Esquizofrenia, bem como para anormalidades nos processos de interacção entre humor e cognição na Esquizofrenia. Ao mesmo tempo, complementam estudos ERP prévios no âmbito do processamento semântico na SW, incluindo, pela primeira vez, participantes tendo como língua nativa o Português Europeu. Espera-se que estes resultados contribuam para uma melhor compreensão das alterações do processamento linguístico, observadas tanto na SW como na Esquizofrenia., Fundação para a Ciência e a Tecnologia (FCT)

In this paper, we present a method for identifying correspondences, or mappings, between alternative features of brainwave activity in event-related potentials (ERP) data The goal is to simulate mapping across results from heterogeneous methods that might be used in different neuroscience research labs The input to the mapping consists of two ERP datasets whose spatiotemporal characteristics are captured by alternative sets of features, that is, summary spatial and temporal measures capturing distinct neural patterns that are linked to concepts in a set of ERP ontologies, called NEMO (Neural ElectroMagnetic Ontologies) [3, 6] The feature value vector of each summary metric is transformed into a point-sequence curve, and clustering is performed to extract similar subsequences (clusters) representing the neural patterns that can then be aligned across datasets Finally, the similarity between measures is derived by calculating the similarity between corresponding point-sequence curves Experiment results showed that the proposed approach is robust and has achieved significant improvement on precision than previous algorithms.

人工内耳患者9名に対し二音弁別課題 (オドボール課題) を課し, 正答率, 反応時間を記録し, 二音弁別能について検討した。 その結果, 人工内耳患者9名の, 1000Hzと, 2000Hzの二つの純音の弁別検査での正答率は平均91.7%で, 反応時間は平均381.5msであった。 二音の周波数差が小さくなるにつれ, 健常者では通常みられないほど, 正答率は低下し反応時間は有意に延長した。 反応時間は大脳での情報処理時間を反映していると思われるので, この検査は人工内耳によって変化する患者の中枢聴覚機能の状態を検出できる可能性を示した。 また成績には大きな個人差が認められた。 さらに二音弁別検査の成績と言語聴取能検査の成績の間には強い相関があり, 純音の二音弁別能がその患者の言語聴取能を評価し得る一つの指標となる可能性を認めた。

The study aims to explore the significance of event-related potentials (ERPs) and event-related brain oscillations (EROs) (delta, theta, and alpha power) in response to emotional face during 180-250 poststimulus time interval. Twenty-one adults looked at emotional (sad, happy, fearful) or neutral faces. The results demonstrated that the emotional face elicited a negative peak at approximately 230 ms (N230). Moreover EEG measures showed that motivational significance of face (stimulus type) can modulate the amplitude of EEG, especially for theta and delta. Regression analysis showed that theta oscillations mainly effect as oscillation activity at the N2 latency. Thus, this frequency band variation could represent a complex set of cognitive processes, whereby selective attention becomes focused on an emotional relevant stimulus.

This study examined the effects of aging on the ERP components associated with the different processing stages in a face naming task. Two hundred photographs were presented to 13 young and 10 elderly adults, who had to press a button and then to say the name aloud (KNOW condition), or “Can’t remember” if they were experiencing a tip-of-the-tongue state (TOT condition). Young adults showed larger ERP amplitudes in KNOW than in TOT in the 550–750 and 1550–2000 ms intervals, but the older adults did not show any such differences. The older adults showed a specific lengthening in ERP latencies from 250 ms onwards, and smaller mean amplitudes in the 550–750 ms interval in the KNOW category and in the 750–1000 ms interval in both categories, and a wider and more frontalized scalp topographical distribution of the ERP amplitudes than the young adults. The results may indicate activation of compensatory mechanisms in elderly adults.

We investigated the spatial correspondence between functional MRI (fMRI) activations and cortical current density maps of event-related potentials (ERPs) reconstructed without fMRI priors. The presence of a significant spatial correspondence is a prerequisite for direct integration of the two modalities, enabling to combine the high spatial resolution of fMRI with the high temporal resolution of ERPs. Four separate tasks were employed: visual stimulation with a pattern-reversal chequerboard, recognition of images of nameable objects, recognition of written words, and auditory stimulation with a piano note. ERPs were acquired with 19 recording channels, and source localisation was performed using a realistic head model, a standard cortical mesh and the multiple sparse priors method. Spatial correspondence was evaluated at group level over 10 subjects, by means of a voxel-by-voxel test and a test on the distribution of local maxima. Although not complete, it was significant for the visual stimulation task, image and word recognition tasks (P < 0.001 for both types of test), but not for the auditory stimulation task. These findings indicate that partial but significant spatial correspondence between the two modalities can be found even with a small number of channels, for three of the four tasks employed. Absence of correspondence for the auditory stimulation task was caused by the unfavourable situation of the activated cortex being perpendicular to the overlying scalp, whose consequences were exacerbated by the small number of channels. The present study corroborates existing literature in this field, and may be of particular relevance to those interested in combining fMRI with ERPs acquired with the standard 10-20 system.

Several studies have shown a relationship between BISH and cerebrovascular events, but no studies have investigated a relationship with cognitive function. The aim was to assess the cognitive function in the elderly with recent BISH. According to WHO Guidelines (1999), we selected 10 elderly normotensives, 10 elderly with recently diagnosed (

Localization of the cognitive activity in the brain is one of the major problems in neuroscience. Current techniques for neuro-imaging are based on Functional Magnetic Resonance Imaging (fMRI), Positron Emission Tomography (PET), and Event Related Potential (ERP) recordings. The highest temporal resolution is achieved by ERP, which is crucial for temporal localization of activities. However, the spatial resolution of scalp topography for ERP is low. There is a severe limitation for the parametric inverse solution algorithms that they can only perform well for the temporally uncorrelated sources. In this study, a spatial decomposition method is proposed to separate the temporally correlated sources using their topographies prior to their localization. Index Terms—Spatial Wavelet Decomposition, ERP, Source Localization, Brain Topography

Duyumsal ve bilişsel süreçleri yansıtan olaya ilişkin potansiyeller (OİP), beyninyüksek bilişsel süreçlerde nasıl çalıştığına dair elekrofizyolojiksel ışık tutmaktadır.OİP'lerin spektral bileşenleri ve P300 alt bileşeni bireyler arası değişkenliğe sahipolduğu kadar yüksek oranda kalıtsal olma özelliğine de sahiptir. OİP'lerin bukalısallık özelliğine atfedilen adaylar, bazı önemli neurotransmitter reseptörlerinikodlayan genlerdir. Bu çalışmada, glutamat reseptör 2A alt birimi (NMDAR2A),GABA reseptör gamma-2 alt birimi (GABRG2), ve dopamin reseptör D2 alt biriminikodlayan genlerdeki fonksiyonel polimorfizmlerin işitsel OİP'lerle olan ilişkileriincelendi. Bunun için 72 sağlıklı erkek gönüllünün EEG kayıtları alındı ve genetikanalizleri yapıldı. İstatistiksel çalışma için, her üç polimorfizm tipine göre ayrıgruplar oluşturuldu. Üç farklı bilişsel paradigma uygulanarak işitsel OİP'ler eldeedildi. ERP kayıtları P300 latans ve genliği ölçülmek suretiyle zaman alanında, vedaha sonra dalgacık dönüşümü yöntemi kullanılarak zaman-frekans alanındavaryans analizi (ANOVA) ile incelendi. Alınan sonuçlar, GABRG2 polimorfizmininhem zaman hem de zaman-frekans alanında OİP'ler üzerinde önemli bir etkisiolduğunu gösterdi. Diğer iki polimorfizmin P300 üzerindeki etkilerinin ise daha azolduğu tespit edildi. Bununla beraber, spesifik frekans bantlarının zaman-frekansalanındaki analizleri, bu üç polimorfizmin OİP'ler üzerinde sadece zaman alanındakianalizlerinde farkedilemeyen daha başka etkileri de olduğunu gösterdi. Bu çalışma,normal populasyondaki genetik farklılıkların elektrofizyolojik parametrelerleilişkilerini göstererek, bilişsel aktivitelerin genetik temelleri üzerindeki bilgilerimizigenişletmiştir.Anahtar Sözcükler: Olaya İlişkin Potansiyel (OİP), P300, Polimorfizm, Reseptör,NMDAR2A, GABRG2, DRD2, Zaman Alanı, Zaman-Frekans Alanı, DalgacıkDönüşümü. Event related potentials (ERPs) reflect perceptual and cognitive processes andtherefore provide an electrophysiological window onto brain function duringcognition. P300 component as well as spectral components of ERPs are highlyheritable. Potential candidates for the genetic determinants of ERPs are genesencoding several most important neurotransmitter receptors. In this study, we aimedto identify associations of functional polymorphisms of genes encoding glutamatereceptor 2A subunit, (NMDAR2A), GABA receptor gamma-2 subunit (GABRG2) anddopamine receptor D2 subunit (DRD2) with auditory ERPs. EEG recordings andgenetic analysis of 72 Turkish male healthy volunteers were performed in this study.Groups were formed according to their polymorphism types for each of the threeneurotransmitter receptors. Three cognitive paradigms were designed to generateauditory ERPs. ERP recordings of each polymorphic group were analyzed in the timedomain by measuring P300 amplitude and latency, and furthermore, in the time-frequency domain by decomposition of ERP signals via using wavelet transform withanalysis of variance (ANOVA). Results provide evidence of strong effect of GABRG2polymorphism with ERP characteristics both in time domain and in time-frequencydomain. The effects of NMDAR2A and DRD2 polymorphisms are less significant onP300 wave. However, time-frequency decomposition of ERP data showed other effectscould be observed in specific frequency bands of all three polymorphisms that werenot reflected in the time-domain representation of the data. The results of this studyshow that extended analyses on the correlations of genetic differences among normalpopulation on electrophysiological parameters may extend our view on the geneticbasis of cognitive activities.Keywords: Event Related Potential (ERP), P300, Polymorphism, Receptor,NMDAR2A, GABRG2, DRD2, Time-Frequency Domain Analysis, WaveletTransform. 95