Event-related Brain Potentials Research Articles

Recording Neural Reward Signals in a Naturalistic Operant Task Using Mobile-EEG and Augmented Reality.

The electrophysiological response to rewards recorded during laboratory tasks has been well documented, yet little is known about the neural response patterns in a more naturalistic setting. Here, we combined a mobile-EEG system with an augmented reality headset to record event-related brain potentials (ERPs) while participants engaged in a naturalistic operant task to find rewards. Twenty-five participants were asked to navigate toward a west or east goal location marked by floating orbs, and once participants reached the goal location, the orb would then signify a reward (5 cents) or no-reward (0 cents) outcome. Following the outcome, participants returned to a start location marked by floating purple rings, and once standing in the middle, a 3 s counter signaled the next trial, for a total of 200 trials. Consistent with previous research, reward feedback evoked the reward positivity, an ERP component believed to index the sensitivity of the anterior cingulate cortex to reward prediction error signals. The reward positivity peaked ∼230 ms with a maximal at channel FCz (M = -0.695 μV, ±0.23) and was significantly different than zero (p < 0.01). Participants took ∼3.38 s to reach the goal location and exhibited a general lose-shift (68.3% ±3.5) response strategy and posterror slowing. Overall, these novel findings provide support for the idea that combining mobile-EEG with augmented reality technology is a feasible solution to enhance the ecological validity of human electrophysiological studies of goal-directed behavior and a step toward a new era of human cognitive neuroscience research that blurs the line between laboratory and reality.

An ERP Study on the Processing of Subject-Verb and Object-Verb Gender Agreement in Punjabi.

This study was conducted with the aim of exploring the general parsing mechanisms involved in processing different kinds of dependency relations, namely verb agreement with subjects versus objects in Punjabi, an SOV Indo-Aryan language. Event related brain potentials (ERPs) were recorded as twenty-five native Punjabi speakers read transitive sentences. Critical stimuli were either fully acceptable as regards verb agreement, or alternatively violated gender agreement with the subject or object. A linear mixed-models analysis confirmed a P600 effect at the position of the verb for all violations, regardless of whether subject or object agreement was violated. These results thus suggest that an identical mechanism is involved in gender agreement computation in Punjabi regardless of whether the agreement is with the subject or the object argument.

Task-based default mode network connectivity predicts cognitive impairment and negative symptoms in first-episode schizophrenia.

Individuals diagnosed with schizophrenia (SZ) demonstrate difficulty distinguishing between internally and externally generated stimuli. These aberrations in "source monitoring" have been theorized as contributing to symptoms of the disorder, including hallucinations and delusions. Altered connectivity within the default mode network (DMN) of the brain has been proposed as a mechanism through which discrimination between self-generated and externally generated events is disrupted. Source monitoring abnormalities in SZ have additionally been linked to impairments in selective attention and inhibitory processing, which are reliably observed via the N100 component of the event-related brain potential elicited during an auditory paired-stimulus paradigm. Given overlapping constructs associated with DMN connectivity and N100 in SZ, the present investigation evaluated relationships between these measures of disorder-related dysfunction and sought to clarify the nature of task-based DMN function in SZ. DMN connectivity and N100 measures were assessed using EEG recorded from SZ during their first episode of illness (N = 52) and demographically matched healthy comparison participants (N = 25). SZ demonstrated less evoked theta-band connectivity within DMN following presentation of pairs of identical auditory stimuli than HC. Greater DMN connectivity among SZ was associated with better performance on measures of sustained attention (p = .03) and working memory (p = .09), as well as lower severity of negative symptoms, though it was not predictive of N100 measures. Together, present findings provide EEG evidence of lower task-based connectivity among first-episode SZ, reflecting disruptions of DMN functions that support cognitive processes. Attentional processes captured by N100 appear to be supported by different neural mechanisms.

A Wearable Device-Based System: The Potential Role in Real-time and Remote EEG Monitoring

Purpose: In recent years, the Electroencephalography (EEG)-based Brain-Computer Interface (BCI) application has been growing rapidly and has emerged as a technology with high translational potential since it allows disabled people to translate human intentions into control signals and to interact with the external environment without any kinesthetic movement. Individuals with significant health problems can benefit from this technology to improve their independence and facilitate participation in activities, thus improving general well-being and preventing impairments. The rapid advances in technology have led to optimal innovation in the context of wearable health monitoring and remote control solutions. Many wearable devices for capturing EEG signals in daily life have recently been released on the market. Our paper aims to present a wearable de-vice-based system for real-time and remote EEG monitoring, to describe the proposed system modules and the signal processing algorithms, to explore the functionalities of this wearable EEG solution, and to suggest its potential application for daily brain data recordings in the home environment. Materials and Methods: The validity of the Emotiv Epoc+ device in the continuous and real-time EEG signals acquisition and monitoring was demonstrated by means of preliminary test measurements during a resting state paradigm performed by a healthy control subject. Results: Our findings confirmed the Epoc+ reliability for event-related brain potential research and in measuring acceptable spectral EEG data. Conclusion: The described approach, focusing on the emerging area of remote monitoring sensors and wearable device applications, might be leveraged to measure complex health outcomes in non-specialist and remote settings.

Event-related brain potentials in lexical processing with Chinese characters show effects of contextual diversity but not word frequency.

The diversity of contexts in which a word occurs, operationalized as CD, is strongly correlated with response times in visual word recognition, with higher CD words being recognized faster. CD and token word frequency (WF) are highly correlated but in behavioral studies when other variables that affect word visual recognition are controlled for, the WF effect is eliminated when contextual diversity (CD) is controlled. In contrast, the only event-related potential (ERP) study to examine CD and WF Vergara-Martínez et al., Cognitive, Affective, & Behavioral Neuroscience, 17, 461-474, (2017) found effects of both WF and CD with different distributions in the 225- to 325-ms time window. We conducted an ERP study with Chinese characters to explore the neurocognitive dynamics of WF and CD. We compared three groups of characters: (1) characters high in frequency and low in CD; (2) characters low in frequency and low in CD; and (3) characters high in frequency and high in CD. Behavioral data showed significant effects of CD but not WF. Character CD, but not character frequency, modulated the late positive component (LPC): high-CD characters elicited a larger LPC, widely distributed, with largest amplitude at the posterior sites compared to low-CD characters in the 400-to 600-ms time window, consistent with earlier ERP studies of WF in Chinese, and with the hypothesis that CD affects semantic and context-based processes. No WF effect on any ERP components was observed when CD was controlled. The results are consistent with behavioral results showing CD but not WF effects, and in particular with a "context constructionist" framework.

Event-related brain potentials to typing errors in transparent and intransparent German words

Error detection in typing is crucial for assessing the adequacy of ongoing actions, leveraging both predictive mechanisms for early detection and sensory feedback for late detection. Neurophysiological studies have supported the anticipation of errors through predictive models. This research extends the understanding of error detection in typing, focusing on the neurocognitive mechanisms underlying errors in transparent and intransparent German words. Thirty-six volunteer students typed out aurally presented words, classified as either orthographically transparent or intransparent, on a computer keyboard without the possibility of correction. Because of poor spelling or excessive artifacts, the final sample comprised 27 participants. Event-related potentials (ERPs) were obtained time-locked to key presses, and behavioral data on typing correctness and speed were collected. A higher error rate and longer latency for intransparent words compared to transparent ones were found, suggesting the complexity of spelling impacts typing correctness. Post-error slowing was observed, aligning with increased cognitive control following errors. ERPs revealed a negative component akin to the error-related negativity (ERN) for typing errors, with a pronounced ERN-like negativity preceding erroneous key-presses, particularly for intransparent words. The study provides evidence of the cognitive and neural mechanisms underlying typing errors, highlighting the impact of orthographic transparency. The detection of an ERN-like negativity before erroneous key-presses, especially in typing intransparent words, underscores the brain's use of predictive mechanisms for error detection.

An event-related potential investigation of the influence of bilingualism on disambiguating homonyms in older adults.

Ambiguity is ubiquitous in language; lexical ambiguity refers to instances where a single word has multiple meanings. The current investigation examined homonyms, words that have the same orthography and pronunciation in English but multiple meanings (e.g., BANK, meaning "financial institution" or "river's edge"). The processing of homonyms requires the engagement of executive control processes, for example, to select the appropriate meaning of the homonym while reducing interference from other meanings. Executive function processes are known to change over the lifespan and may be impacted by experiential factors such as bilingualism. The present study uses event-related brain potentials as an index of lexical access to examine whether bilingualism influences homonym processing in older adults. The results indicate that patterns of lexical access differ as a function of bilingual status in older adults and compared to young adults, suggesting that language experience may moderate language processing in both young and older adults, at least in situations where language processing is demanding on executive function, such as in the processing of homonyms. Importantly, we show that older bilinguals show a somewhat similar pattern of ambiguity processing as their younger counterparts, while age differences were observed in monolinguals when comparing across studies. This suggests that bilingual language experience may have a mitigating impact on age-related changes in ambiguity processing. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

A premium for positive social interest and attractive voices in the acceptability of unfair offers? An ERP study.

Although the attractiveness of voices plays an important role in social interactions, it is unclear how voice attractiveness and social interest influence social decision-making. Here, we combined the ultimatum game with recording event-related brain potentials (ERPs) and examined the effect of attractive versus unattractive voices of the proposers, expressing positive versus negative social interest ("I like you" vs. "I don't like you"), on the acceptance of the proposal. Overall, fair offers were accepted at significantly higher rates than unfair offers, and high voice attractiveness increased acceptance rates for all proposals. In ERPs in response to the voices, their attractiveness and expressed social interests yielded early additive effects in the N1 component, followed by interactions in the subsequent P2, P3 and N400 components. More importantly, unfair offers elicited a larger Medial Frontal Negativity (MFN) than fair offers but only when the proposer's voice was unattractive or when the voice carried positive social interest. These results suggest that both voice attractiveness and social interest moderate social decision-making and there is a similar "beauty premium" for voices as for faces.

Relevance acquisition through motivational incentives: Modeling the time-course of associative learning and the role of visual features

Abstract Motivational relevance associated with symbolic stimuli impacts both neural and behavioral responses, similar to visual stimuli with inherent emotional valence. However, the specific effects of associated relevance on early sensory stages and lexico-semantic processing of these stimuli remain unclear, particularly considering the role of low-level visual features in relevance acquisition. To address these issues, we employed an associative learning paradigm in which we manipulated visual features, but not the stimuli themselves. The study (N = 48) included a learning phase, where pseudowords were associated with either gain, loss, or neutral outcomes. This was followed by a test phase the next day, involving an old/new decision task, in which stimuli were presented in either the same or a different font. During both phases, pupil responses and event-related brain potentials (P1, Early Posterior Negativity (EPN), Late Positive Complex (LPC), P3) were measured. Stronger pupil responses and increased neural activation in early visual encoding (P1) and lexico-semantic processing (EPN) were observed during relevance acquisition, particularly for loss associations. After relevance acquisition, the most substantial effect on modulating lexico-semantic processing was observed for gain associations, as evidenced by both behavioral responses and neural activity. During the test phase, exposure to incongruent visual features of the stimuli influenced the same processes that were observed during relevance acquisition. Notably, these effects of visual feature congruence were independent of those of associated motivational relevance. These results highlight the dynamic nature of motivational relevance effects, revealing differential effects observed during acquisition and the test phase, as well as between earlier perceptual processing and later neural and behavioral responses.

Acute resistance exercise combined with whole body vibration and blood flow restriction: Molecular and neurocognitive effects in late-middle-aged and older adults

Limited research exists regarding the effects of resistance exercise (RE) combined with whole body vibration (WBV), blood flow restriction (BFR), or both on the neuropsychological performance of working memory (WM) in late-middle-aged and older adults and regarding the physiological mechanisms underlying this effect. This study thus explored the acute molecular and neurophysiological mechanisms underlying WM performance following RE combined with WBV, BFR, or both. Sixty-six participants were randomly assigned into a WBV, BFR, or WBV + BFR group. Before and after the participants engaged in a single bout of isometric RE combined with WBV, BFR, or both, this study gathered data on several neurocognitive measures of WM performance, namely, accuracy rate (AR), reaction time (RT), and brain event-related potential (specifically P3 latency and amplitude), and data on biochemical indices, such as the levels of insulin-like growth factor-1 (IGF-1), norepinephrine (NE), and brain-derived neurotrophic factor (BDNF). Although none of the RE modalities significantly affected RTs and P3 latencies, ARs and P3 amplitudes significantly improved in the WBV and WBV + BFR groups. The WBV + BFR group exhibited greater improvements than the WBV group did. Following acute RE combined with WBV, BFR, or both, IGF-1 and NE levels significantly increased in all groups, whereas BDNF levels did not change. Crucially, only the changes in NE levels were significantly correlated with improvements in ARs in the WBV + BFR and WBV groups. The findings suggest that combining acute RE with WBV, BFR, or both could distinctively mitigate neurocognitive decline in late-middle-aged and older adults.

Slips of the tongue in patients with Gilles de la Tourette syndrome

BackgroundMotor and vocal tics are the main symptom of Gilles de la Tourette-syndrome (GTS). A particular complex vocal tic comprises the utterance of swear words, termed coprolalia. Since taboo words are socially inappropriate, they are normally suppressed by people, which implies cognitive control processes.MethodTo investigate the control of the unintentional pronunciation of taboo words and the associated processes of conflict monitoring, we used the “Spoonerisms of Laboratory Induced Predisposition” (SLIP) paradigm. Participants read multiple inductor word pairs with the same phonemes, followed by pronouncing a target pair with inverse phonemes. This led to a conflict between two competing speech plans: the correct word pair and the word pair with inverted phonemes. Latter speech error, a spoonerism, could result in a neutral or taboo word. We investigated 19 patients with GTS and 23 typically developed controls (TDC) and measured participants’ electroencephalography (EEG) during the SLIP task.ResultsAt the behavioral level less taboo than neutral word spoonerisms occurred in both groups without significant differences. Event-related brain potentials (ERP) revealed a difference between taboo and neutral word conditions in the GTS group at the midline electrodes in a time range of 250–400 ms after the speech prompt, which was not found in the TDC group. The extent of this effect depended on the number of inductor word pairs, suggesting an increasing level of cognitive control in the GTS group.ConclusionThe differences between taboo and neutral word conditions in patients with GTS compared to TDC suggest an altered recruitment of cognitive control processes in GTS, likely enlisted to suppress taboo words.

Beyond Explicit Acknowledgment: Brain Response Evidence of Human Skepticism towards Robotic Emotions

Using the N400 component of event-related brain potentials, a neurophysiological marker associated with processing incongruity, we examined brain responses to sentences spoken by a robot that had no arms or legs. Statements concerning physically impossible actions (e.g., knitting) elicit significant N400 responses, reflecting that participants perceived these statements as incongruent with the robot’s physical condition. However, this effect was attenuated for participants who indicated that the robot could have hidden limbs, indicating that expectations modify the way an agent’s utterances are interpreted. When it came to statements relating to emotional capabilities a distinct pattern was found. Although participants acknowledged that the robot could have emotions, there were significant N400 responses to statements about the robot’s emotional experiences (e.g., feeling happy). This effect was not modified by participants’ beliefs, suggesting a cognitive challenge of accepting robots as capable of experiencing emotions. Our findings thus point to a boundary in human acceptance of artificial social agents: while physical attributes may be negotiable based on expectations, emotional expressions are more difficult to establish as credible. By elucidating the cognitive mechanisms at play, our study informs the design of social robots that are capable of more effective communication to better support social connectivity and human well-being.

Unpleasant emotion inhibits attentional focus toward a peripheral target in a visual search: an ERP study.

Previous studies have found that emotional states affect the extent of attention, and the effect has been explained by adaptive views. If the adaptive explanations are true, emotion should modulate attentional focus toward a peripheral stimulus. The present study investigated if emotion affects the focus of attention toward a peripheral target in a visual search paradigm with event-related brain potential (ERP) measurement. In each trial of the experiment, participants performed a visual search task after an emotion (unpleasant, neutral, or pleasant) was induced by presenting an international affective picture system (IAPS) image. We measured N2pc, which is an ERP index reflecting attentional focus toward a peripheral target in a visual search, and compared the amplitudes among the emotion conditions. According to the adaptive view of emotional effects on cognition, this study hypothesized that unpleasant emotion would enhance the focus of attention, and pleasant emotion would inhibit it. These hypotheses predicted that N2pc amplitude would increase with unpleasant emotion and decrease with pleasant emotion. However, this study obtained inconsistent results; N2pc amplitude decreased in the unpleasant condition, and there was no significant effect of pleasant emotion on the ERP. The results suggest that unpleasant emotion inhibited the attentional focusing process. This is the first report to examine how emotion modulates the focus of attention toward a peripheral target in a visual search by using ERP. The findings contribute to understanding the relationship between emotion and cognition.

FC-TFS-CGRU: A Temporal-Frequency-Spatial Electroencephalography Emotion Recognition Model Based on Functional Connectivity and a Convolutional Gated Recurrent Unit Hybrid Architecture.

The gated recurrent unit (GRU) network can effectively capture temporal information for 1D signals, such as electroencephalography and event-related brain potential, and it has been widely used in the field of EEG emotion recognition. However, multi-domain features, including the spatial, frequency, and temporal features of EEG signals, contribute to emotion recognition, while GRUs show some limitations in capturing frequency-spatial features. Thus, we proposed a hybrid architecture of convolutional neural networks and GRUs (CGRU) to effectively capture the complementary temporal features and spatial-frequency features hidden in signal channels. In addition, to investigate the interactions among different brain regions during emotional information processing, we considered the functional connectivity relationship of the brain by introducing a phase-locking value to calculate the phase difference between the EEG channels to gain spatial information based on functional connectivity. Then, in the classification module, we incorporated attention constraints to address the issue of the uneven recognition contribution of EEG signal features. Finally, we conducted experiments on the DEAP and DREAMER databases. The results demonstrated that our model outperforms the other models with remarkable recognition accuracy of 99.51%, 99.60%, and 99.59% (58.67%, 65.74%, and 67.05%) on DEAP and 98.63%, 98.7%, and 98.71% (75.65%, 75.89%, and 71.71%) on DREAMER in a subject-dependent experiment (subject-independent experiment) for arousal, valence, and dominance.

Effects of anxiety state on N400 event-related brain potential response to unexpected semantic stimuli

Emotional states can influence how people use meaningful context to make predictions about what comes next. To measure whether state anxiety influences such prediction, we used the N400 event-related brain potential (ERP) response to semantic stimuli, whose amplitude is smaller (less negative) when the stimulus is more predicted based on preceding context. Participants (n = 28) were randomized to one of two groups, who underwent either an “anxious-uncertainty” procedure previously shown to increase anxiety, or a control procedure. Both before and after this procedure, participants’ ERPs were recorded while they viewed category definitions (e.g., “a type of fruit”), each followed by a target word that was either a high-typicality category exemplar (“apple”), low-typicality exemplar (“cherry”), or non-exemplar (“clamp”) of the category. Participants’ task was to respond by pressing one of two buttons to indicate whether the target represented a member of the category. As expected, based on previous work, overall, N400 amplitudes were largest (most negative) in response to non-exemplars, intermediate to low-typicality exemplars, and smallest to high-typicality exemplars. N400 amplitudes were larger to non-exemplars after the anxious-uncertainty procedure than after the control procedure. N400 amplitudes to both types of exemplars did not differ after the anxious-uncertainty procedure versus the control procedure. The results are consistent with participants devoting more neural resources to processing contextually unexpected items under anxious states, rather than anxiety facilitating processing of expected items.

Neural oscillation to music processing in children with different language backgrounds

Musical experience and tonal language experience are both associated with structural and functional changes in the brain that underlie facilitated pitch perception. We investigated whether neuronal oscillations in response to music were correlated with musical expertise and whether they reflected the language backgrounds (tonal versus nontonal, monolingual versus bilingual). We measured music processing in bilingual children (5–10 years old) from Mandarin (a tone language) households and three groups of age-matched children from non-tone language households (Bilingual Spanish-English, monolingual mainstream American English (MAE), and African American English (AAE)). Event-related brain potentials (ERPs) were recorded in an oddball paradigm with six types of music changes. We analyzed the phase locking and amplitude modulations of ongoing oscillations in the theta (4–8 Hz) alpha (8–14 Hz), beta- (14–30 Hz), and gamma- (30– 80 Hz) bands to music changes. Preliminary results suggest that musical expertise was associated with strengthened phase locking of neural oscillations to most music features. Tonal language experience was also associated with more robust phase locking. Bilingual experience alone does not show any enhancement in neural oscillation. There were no clear advantages of music processing for the bilingual experience.

Machine Learning Classification of Event-Related Brain Potentials during a Visual Go/NoGo Task.

Machine learning (ML) methods are increasingly being applied to analyze biological signals. For example, ML methods have been successfully applied to the human electroencephalogram (EEG) to classify neural signals as pathological or non-pathological and to predict working memory performance in healthy and psychiatric patients. ML approaches can quickly process large volumes of data to reveal patterns that may be missed by humans. This study investigated the accuracy of ML methods at classifying the brain's electrical activity to cognitive events, i.e., event-related brain potentials (ERPs). ERPs are extracted from the ongoing EEG and represent electrical potentials in response to specific events. ERPs were evoked during a visual Go/NoGo task. The Go/NoGo task requires a button press on Go trials and response withholding on NoGo trials. NoGo trials elicit neural activity associated with inhibitory control processes. We compared the accuracy of six ML algorithms at classifying the ERPs associated with each trial type. The raw electrical signals were fed to all ML algorithms to build predictive models. The same raw data were then truncated in length and fitted to multiple dynamic state space models of order nx using a continuous-time subspace-based system identification algorithm. The 4nx numerator and denominator parameters of the transfer function of the state space model were then used as substitutes for the data. Dimensionality reduction simplifies classification, reduces noise, and may ultimately improve the predictive power of ML models. Our findings revealed that all ML methods correctly classified the electrical signal associated with each trial type with a high degree of accuracy, and accuracy remained high after parameterization was applied. We discuss the models and the usefulness of the parameterization.

Quantifying the effects of practicing a semantic task according to subclinical schizotypy

The learning ability of individuals within the schizophrenia spectrum is crucial for their psychosocial rehabilitation. When selecting a treatment, it is thus essential to consider the impact of medications on practice effects, an important type of learning ability. To achieve this end goal, a pre-treatment test has to be developed and tested in healthy participants first. This is the aim of the current work, which takes advantage of the schizotypal traits present in these participants to preliminary assess the test’s validity for use among patients. In this study, 47 healthy participants completed the Schizotypal Personality Questionnaire (SPQ) and performed a semantic categorization task twice, with a 1.5-hour gap between sessions. Practice was found to reduce reaction times (RTs) in both low- and high-SPQ scorers. Additionally, practice decreased the amplitudes of the N400 event-related brain potentials elicited by semantically matching words in low SPQ scorers only, which shows the sensitivity of the task to schizotypy. Across the two sessions, both RTs and N400 amplitudes had good test–retest reliability. This task could thus be a valuable tool. Ongoing studies are currently evaluating the impact of fully deceptive placebos and of real antipsychotic medications on these practice effects. This round of research should subsequently assist psychiatrists in making informed decisions about selecting the most suitable medication for the psychosocial rehabilitation of a patient.

Response monitoring in math-anxious individuals in an arithmetic task

We examine whether math anxiety is related to altered response monitoring in an arithmetic task. Response-locked event-related brain potentials (ERPs) were evaluated in 23 highly (HMA) and 23 low math-anxious (LMA) individuals while they performed an arithmetic verification task. We focused on two widely studied ERPs elicited during error processing: error-related negativity (ERN) and error positivity (Pe). Correct-related negativity (CRN), an ERP elicited after a correct response, was also studied. The expected ERN following errors was found, but groups did not differ in its amplitude. Importantly, LMA individuals showed less negative CRN and more positive Pe amplitudes than their more anxious peers, suggesting more certainty regarding response accuracy and better adaptive behavioral adjustment after committing errors in an arithmetic task in the LMA group. The worse control over response performance and less awareness of correct responses in the HMA group might reduce their ability to ‘learn from errors’.

Emotional congruency between faces and words benefits emotional judgments in women: An event-related potential study

The present study aimed to investigate the effects of emotional congruency between faces and words on word evaluation through event-related brain potentials (ERPs). To this end, 20 women performed a face-word congruency task in which an emotional face was presented simultaneously with an affective word in a non-superimposed format. Participants had to evaluate the emotional valence of the word in three different conditions: congruent, incongruent, and control. The emotionally congruent words were categorized faster and more accurately than the incongruent ones. In addition, the emotionally congruent words elicited higher P3/LPP amplitudes than the incongruent ones. These results indicate a beneficial effect of emotional face-word congruency on emotional judgments of words.