Event-related Potential Recordings Research Articles

Frequency Effects on Spelling Error Recognition: An ERP Study.

Spelling errors are ubiquitous in all writing systems. Most studies exploring spelling errors focused on the phonological plausibility of errors. However, unlike typical pseudohomophones, spelling errors occur in naturally produced written language. We investigated the time course of recognition of the most frequent orthographic errors in Russian (error in an unstressed vowel in the root) and the effect of word frequency on this process. During event-related potentials (ERP) recording, 26 native Russian speakers silently read high-frequency correctly spelled words, low-frequency correctly spelled words, high-frequency words with errors, and low-frequency words with errors. The amplitude of P200 was more positive for correctly spelled words than for misspelled words and did not depend on the frequency of the words. In addition, in the 350–500-ms time window, we found a more negative response for misspelled words than for correctly spelled words in parietal–temporal-occipital regions regardless of word frequency. Considering our results in the context of a dual-route model, we concluded that recognizing misspelled high-frequency and low-frequency words involves common orthographic and phonological processes associated with P200 and N400 components such as whole word orthography processing and activation of phonological representations correspondingly. However, at the 500–700 ms stage (associated with lexical-semantic access in our study), error recognition depends on the word frequency. One possible explanation for these differences could be that at the 500–700 ms stage recognition of high-frequency misspelled and correctly spelled words shifts from phonological to orthographic processes, while low-frequency misspelled words are accompanied by more prolonged phonological activation. We believe these processes may be associated with different ERP components P300 and N400, reflecting a temporal overlap between categorization processes based on orthographic properties for high-frequency words and phonological processes for low-frequency words. Therefore, our results complement existing reading models and demonstrate that the neuronal underpinnings of spelling error recognition during reading may depend on word frequency.

Does transcranial direct current stimulation enhance cognitive performance in Parkinson's disease mild cognitive impairment? An event-related potentials and neuropsychological assessment study.

Parkinson's disease-mild cognitive impairment (PD-MCI) is garnering attention as a key interventional period for cognitive impairment. Currently, there are no approved treatments for PD-MCI and encouraging results of transcranial direct current stimulation (tDCS) combined with other interventions have been proposed, though the efficacy and neural mechanisms of tDCS alone have not been studied in PD-MCI yet. The present double-blind, randomized, sham-controlled study assessed the effects of tDCS over the dorsolateral prefrontal cortex on cognitive functions via neuropsychological and electrophysiological evaluations in individuals with PD-MCI for the first time. Twenty-six individuals with PD-MCI were administered 10 sessions of active (n = 13) or sham (n = 13) prefrontal tDCS twice a day, for 5days. Changes were tested through a comprehensive neuropsychological battery and event-related potential recordings, which were performed before, immediately, and 1month after the administrations. Neuropsychological assessment showed an improvement in delayed recall and executive functions in the active group. N1 amplitudes in response to targets in the oddball test-likely indexing attention and discriminability and NoGo N2 amplitudes in the continuous performance test-likely indexing cognitive control and conflict monitoring increased in the active group. Active stimulation elicited higher benefits 1month after the administrations. The present findings substantiate the efficacy of tDCS on cognitive control and episodic memory, along with the neural underpinnings of cognitive control, highlighting its potential for therapeutic utility in PD-MCI. NCT 04,171,804. Date of registration: 21/11/2019.

Semantic Transparency in Chinese Compound Word Processing: Evidence from Mismatch Negativity

This study examined how semantic transparency modulated the processing of spoken Chinese compound words with event-related potential (ERP) recording. A reverse-block passive oddball paradigm was adopted to elicit mismatch negativity (MMN), which responds to holistic and combinatorial processing in opposite directions. Specifically, linguistic inputs that are processed as holistic lexical representations will elicit stronger MMNs (lexical enhancement) than those that do not have such representations. In contrast, when they are processed by combining the constituents, smaller MMNs will be elicited (combinatorial reduction) as compared to non-combinable inputs. We compared the strengths of MMNs among transparent words, opaque words, and pseudocompounds (that did not have lexical representations and were non-combinable). It was shown that transparent words triggered smaller MMNs than pseudocompounds, which supported combinatorial processing. Opaque words did not differ from pseudocompounds, which was interpreted as parallel employment of the holistic and combinatorial processing routes. Overall, the results are consistent with the idea that native Chinese speakers routinely attempt to process Chinese compound words by retrieving and combining morphemes. However, because the meanings of opaque words are irrelevant to their constituent morphemes, Chinese speakers must construct and retrieve their holistic representations to ensure accurate processing.

Dynamic brainstem and somatosensory cortical excitability during migraine cycles

BackgroundMigraine has complex pathophysiological characteristics and episodic attacks. To decipher the cyclic neurophysiological features of migraine attacks, in this study, we compared neuronal excitability in the brainstem and primary somatosensory (S1) region between migraine phases for 30 consecutive days in two patients with episodic migraine.MethodsBoth patients underwent EEG recording of event-related potentials with the somatosensory and paired-pulse paradigms for 30 consecutive days. The migraine cycle was divided into the following phases: 24–48 h before headache onset (Pre2), within 24 h before headache onset (Pre1), during the migraine attack (Ictal), within 24 h after headache offset (Post1), and the interval of ˃48 h between the last and next headache phase (Interictal). The normalised current intensity in the brainstem and S1 and gating ratio in the S1 were recorded and examined.ResultsSix migraine cycles (three for each patient) were analysed. In both patients, the somatosensory excitability in the brainstem (peaking at 12–14 ms after stimulation) and S1 (peaking at 18–19 ms after stimulation) peaked in the Pre1 phase. The S1 inhibitory capability was higher in the Ictal phase than in the Pre1 phase.ConclusionThis study demonstrates that migraine is a cyclic excitatory disorder and that the neural substrates involved include the somatosensory system, starting in the brainstem and spanning subsequently to the S1 before the migraine occurs. Further investigations with larger sample sizes are warranted.

Clinical and neurophysiological patterns of impairments to emotion attention and empathy in multiple sclerosis.

Patients suffering from multiple sclerosis experience various cognitive and affective impairments, resulting in a negative impact on social behavior and personal independence to differing degrees. According to these often clinically subtle but conflicting cognitive-affective impairments, recordings of these socially relevant issues are still of demand to stratifying clinical and social support in a sophisticated way. Therefore, we studied specific cognitive and affective capacities in eleven patients with a predominant relapsing-remitting type of multiple sclerosis by applying paradigms of event-related potentials and a well-selected neuropsychological test protocol. Thus far, distinct cognitive disturbances of executive and attentional domains and the Wechsler Memory Test's four memory indices were found in multiple sclerosis patients. Concerning affective domains, patients showed discrete impairments of affect discrimination and affected naming as proved by specific testing (Tuebinger Affect Battery). Neurophysiologically, event-related potentials recordings in multiple sclerosis patients, were associated with decreased implicit emotion processing to cues of different emotion arousal at the early processing stage depending on attentional capacities and alterations of implicit emotion modulation at late processing stages. These clinical neurophysiological and neuropsychological data were correlated in part to quantitative magnetic resonance imaging brain lesions. Summarizing our data, our data indicate certain neurocognitive and neuroaffective dysfunctions in patients with multiple sclerosis, thus highlighting the validity of sensitive recording of less apparent neurologic disturbances in multiple sclerosis for optimizing the individual care management in patients.

Interactions of stimulus quality and semantic context on N400 in visual word recognition

AbstractThe joint effects of stimulus quality and semantic context in visual word recognition were examined with event-related potential (ERP) recordings. In one-character Chinese word recognition, we manipulated stimulus quality at two degradation levels (highly vs. slightly degraded) and semantic context at two priming levels (semantically related vs. unrelated). In a prime–target–probe trial flow, ERPs were recorded to the target character which was presented in either high or slight degradation and which was preceded by either a semantically related or unrelated prime character. The target character was then followed by a probe character which was either identical to or different from the target character. Subjects were instructed to make target–probe matching judgments. The ERP results demonstrated a degradation by priming interaction, with larger N400 semantic priming effects for slightly degraded targets. Moreover, the degradation effects were observed on the P200, N250, and N400. These findings provided evidence for the cascaded model of visual word recognition such that the visual processing cascaded into the semantic stage and thus interacted on the N400 amplitude. The results were compared to an earlier study with a null ERP degradation by priming interaction. The ramifications of these results for models of visual word recognition are discussed.

Combining Topical Agonists With the Recording of Event-Related Brain Potentials to Probe the Functional Involvement of TRPM8, TRPA1 and TRPV1 in Heat and Cold Transduction in the Human Skin

TRP channels play a central role in the transduction of thermal and nociceptive stimuli by free nerve endings. Most of the research on these channels has been conducted in vitro or in vivo in nonhuman animals and translation of these results to humans must account for potential experimental biases and interspecific differences. This study aimed at evaluating the involvement of TRPM8, TRPA1 and TRPV1 channels in the transduction of heat and cold stimuli by the human thermonociceptive system. For this purpose, we evaluated the effects of topical agonists of these 3 channels (menthol, cinnamaldehyde and capsaicin) on the event-related brain potentials (ERPs) elicited by phasic thermal stimuli (target temperatures: 10°C, 42°C, and 60°C) selected to activate cold Aδ thermoreceptors, warm sensitive C thermoreceptors and heat sensitive Aδ polymodal nociceptors. Sixty-four participants were recruited, 16 allocated to each agonist solution group (20% menthol, 10% cinnamaldehyde, .025% capsaicin and 1% capsaicin). Participants were treated sequentially with the active solution on one forearm and vehicle only on the other forearm for 20 minutes. Menthol decreased the amplitude and increased the latency of cold and heat ERPs. Cinnamic aldehyde decreased the amplitude and increased the latency of heat but not cold ERPs. Capsaicin decreased the amplitude and increased the latency of heat ERPs and decreased the amplitude of the N2P2 complex of the cold ERPs without affecting the earlier N1 wave or the latencies of the peaks. These findings are compatible with previous evidence indicating that TRPM8 is involved in innocuous cold transduction and that TRPV1 and TRPA1 are involved in noxious heat transduction in humans. PerspectiveBy chemically modulating TRPM8, TRPA1 and TRPV1 reactivity (key molecules in the transduction of temperature) and assessing how this affected EEG responses to the activation of cold thermoreceptors and heat nociceptors, we aimed at confirming the role of these channels in a functional healthy human model.

The neural habituation to hedonic and eudaimonic rewards: Evidence from reward positivity.

Rewards play an important role in people's well-being. However, the mechanisms underlying neural habituation to hedonic rewards (attainment of pleasure) and eudaimonic rewards (attainment of meaning and self-realization) and their implications for longitudinal changes in well-being remain unknown. By operationalizing hedonic rewards as "winning money for oneself" and eudaimonic rewards as "winning money for a charity", 78 participants (41 women, aged from 17 to 24years) completed a revised monetary gambling task during event-related potential (ERP) recording. Subsequently, the participants' well-being was measured after one year. The results showed that the reward positivity (RewP) effect readily decreased as the hedonic rewards were repeated, whereas the RewP effect in response to eudaimonic rewards was relatively sustained over time. Moreover, the declining RewP effect for repeated eudaimonic rewards was marginally positively associated with longitudinal decreases in well-being. These findings demonstrate at the neural level that sensitivity to repeated hedonic rewards is more prone to decrease than sensitivity to repeated eudaimonic rewards, and sustained eudaimonic reward sensitivity in the short term has greater implications for changes in well-being in the long term.

Long-term Follow-up of Preoperative Infant Event-related Potentials in School-age Children with Craniosynostosis

Previous studies demonstrated impaired auditory processing in children with sagittal and metopic craniosynostosis before surgical correction. This study investigated whether worse presurgical neural response as assessed by event-related potentials (ERP) was predictive of poorer school-age neurocognition. Preoperative infant ERP was recorded in 15 sagittal and 18 metopic patients. Mismatch negativity and P150 paradigms were derived from ERP recordings, as previously published. Of those, 13 sagittal and 13 metopic patients returned for neurocognitive evaluation 6 or more years later. ERP was correlated to neurocognitive outcomes using Spearman's correlations controlling for age. Two-tailed t-tests were used to evaluate the influence of age at the time of surgery (6 months) and morphologic severity on neurocognitive outcomes. In the sagittal group, no significant correlations were found between preoperative mismatch negativity or P150 amplitudes and neurocognitive outcomes. Although no correlation was found between mismatch negativity and neurocognitive outcome in the metopic group, those with lower P150 amplitudes had higher scores in performance IQ (r = -0.877, P < 0.001) and full-scale IQ (r = -0.893, P < 0.001). Morphologic severity and neurocognitive outcomes showed no relationship in the sagittal or metopic groups. Patients who received surgery at less than 6 months had higher full-scale IQ (109.69 versus 95.92, P = 0.025), visuomotor integration (103.15 versus 90.46, P = 0.041), and visual perception scores (105.69 versus 96.08, P = 0.033). Preoperative infant ERP does not correlate with school-age neurocognitive outcomes. Earlier age at the time of surgery was associated with improved neurocognitive outcomes.

A single-session behavioral protocol for successful event-related potential recording in children with neurodevelopmental disorders.

Event-related potentials (ERPs) are an ideal tool for measuring neural responses in a wide range of participants, including children diagnosed with neurodevelopmental disorders (NDDs). However, due to perceived barriers regarding participant compliance, much of this work has excluded children with low IQ and/or reduced adaptive functioning, significant anxiety symptoms, and/or sensory processing difficulties, including heterogeneous samples of children with autism spectrum disorder (ASD) and children with fragile X syndrome (FXS). We have developed a behavioral support protocol designed to obtain high-quality ERP data from children in a single session. Using this approach, ERP data were successfully collected from participants with ASD, FXS, and typical development (TD). Higher success rates were observed for children with ASD and TD than children with FXS. Unique clinical-behavioral characteristics were associated with successful data collection across these groups. Higher chronological age, nonverbal mental age, and receptive language skills were associated with a greater number of valid trials completed in children with ASD. In contrast, higher language ability, lower autism severity, increased anxiety, and increased sensory hyperresponsivity were associated with a greater number of valid trials completed in children with FXS. This work indicates that a "one-size-fits-all" approach cannot be taken to ERP research on children with NDDs, but that a single-session paradigm is feasible and is intended to promote increased representation of children with NDDs in neuroscience research through development of ERP methods that support inclusion of diverse and representative samples.

Perceiving faces through reconnection-colored glasses after social exclusion: Evidence from N100.

Social exclusion motivates individuals to selectively reconnect with others, in which face categorization plays an important role. However, it remains unknown how reconnection possibility interacts with perception at the very early stage of face categorization. To address this issue, after social exclusion or social inclusion priming, participants were instructed to select one person from two gender-matched strangers as a future "coworker" (with high reconnection possibility; the left one is a future "stranger," with low reconnection possibility) for another ostensible task, and then complete an orientation judgment task of self-face, coworker face and stranger face, with event-related brain potential (ERP) recordings. Results showed that excluded participants produced larger N100 to future coworker face than to stranger face, but no such difference was found among included participants. Compared with included participants, excluded participants produced significantly larger N100 to future coworker face. Moreover, N100 elicited by future coworker face was significantly negatively correlated with rating scores of exclusion only for social excluded participants. These findings indicate that social reconnection desire may contribute to the biased face perception which facilitates face categorization of socially excluded people.

I, robot: depression plays different roles in human\u2013human and human\u2013robot interactions

Socially engaging robots have been increasingly applied to alleviate depressive symptoms and to improve the quality of social life among different populations. Seeing that depression negatively influences social reward processing in everyday interaction, we investigate this influence during simulated interactions with humans or robots. In this study, 35 participants with mild depression and 35 controls (all from nonclinical populations) finished the social incentive delay task with event-related potential recording, in which they received performance feedback from other persons or from a robot. Compared to the controls, the mild depressive symptom (MDS) group represented abnormalities of social reward processing in the human feedback condition: first, the MDS group showed a lower hit rate and a smaller contingent-negative variation (correlated with each other) during reward anticipation; second, depression level modulated both the early phase (indexed by the feedback-related negativity (FRN)) and the late phase (indexed by the P3) of reward consumption. In contrast, the effect of depression was evident only on FRN amplitude in the robot feedback condition. We suggest that compared to human–human interaction, the rewarding properties of human–robot interaction are less likely to be affected by depression. These findings have implications for the utilization of robot-assisted intervention in clinical practice.

The upside-down self: One's own face recognition is affected by inversion.

One's own face is recognized more efficiently than any other face, although the neural mechanisms underlying this phenomenon remain poorly understood. Considering the extensive visual experience that we have with our own face, some authors have proposed that self-face recognition involves a more analytical perceptual strategy (i.e., based on face features) than other familiar faces, which are commonly processed holistically (i.e., as a whole). However, this hypothesis has not yet been tested with brain activity data. In the present study, we employed an inversion paradigm combined with event-related potential (ERP) recordings to investigate whether the self-face is processed more analytically. Sixteen healthy participants were asked to identify their own face and a familiar face regardless of its orientation, which could either be upright or inverted. ERP analysis revealed an enhanced amplitude and a delayed latency for the N170 component when faces were presented in an inverted orientation. Critically, both the self and a familiar face were equally vulnerable to the inversion effect, suggesting that the self-face is not processed more analytically than a familiar face. In addition, we replicated the recent finding that the attention-related P200 component is a specific neural index of self-face recognition. Overall, our results suggest that the advantage for self-face processing might be better explained by the engagement of self-related attentional mechanisms than by the use of a more analytical visuoperceptual strategy.

Effects of benzodiazepine and orexin receptor antagonist on cognitive function revealed by auditory event-related potentials.

Cognitive decline after oral administration of sedatives, such as benzodiazepines, is a serious side effect. Suvorexant, an orexin receptor antagonist, has a favorable tolerability and a limited side-effect profile. The purpose of this study was to estimate the cognitive decline 1 day after oral medication with lormetazepam, a benzodiazepine, and suvorexant by comparing mismatch negativity (MMN) and P300 reflecting auditory discrimination function. Sixty healthy subjects (42 males) were randomly assigned to three groups receiving suvorexant 20 mg, lormetazepam 2 mg, or placebo in this double-blind, randomized control study. Event-related potential recordings during an auditory oddball task and a digit symbol substitution test (DSST) were performed 1 day after oral administration. MMN, on the day after oral administration, was significantly attenuated in the lormetazepam group compared with the other two groups, but there was no difference between the suvorexant and placebo groups. No significant difference was found in P300 amplitudes and DSST scores among the three groups. These findings suggest that suvorexant, unlike benzodiazepine, is not associated with cognitive deficits, as revealed by MMN but not P300. This study shows a neurophysiological difference in the effects of suvorexant and benzodiazepine on cognitive function.

5: Long-term Follow-up of Pre-operative Infant Event-related Potential in Children with Craniosynostosis

Purpose:Event-related potentials (ERPs) provide a real-time safe, noninvasive method to assess neural networks in infancy. Limited data exist, however, as to the predictive value of these results with eventual neurocognitive outcomes at school age. The purpose of this study was to investigate whether ERP recordings at infancy also translated into neurocognitive deficits at school age.Methods:16 infants who underwent evaluation of auditory processing in infancy were followed up for neurocognitive testing. ERPs were extracted from electroencephalographic data evoked in response to language stimuli, and were found to have a positive inflection peaking 150 to 300msec (P150) after presentation of the stimuli, followed by a negative wave 300 to 700msec (N450) after. The P150 and N450 components were examined over the right and left frontotemporal scalp areas. Patients underwent a battery of neurocognitive tests including assessments of IQ (Weschler Abbreviated Scale of Intelligence 2nd edition), academic achievement (Kaufman Test of Educational Achievement 3rd edition), and motor coordination (Beery-Buktenica Development Test of Visual-Motor Integration 6th edition). Absolute deviation of ERP results from age-matched controls were computed. Spearman’s correlations were used to assess the strength of correlation between neurocognitive scores and ERP values, as well as other sociodemographic variables.Results:11 patients with ERP in infancy were neurocognitively tested. Average time to follow-up neurocognitive testing was 10.1 ± 1.7 years. 7 (63.6%) were male, 9 (81.8%) were white. 7 (63.6%) underwent whole vault cranioplasty while 4 (36.4%) underwent endoscopic strip craniectomy. Mean age at surgery was 7.4±2.5 months. A greater absolute difference from age-matched controls in the left-sided P150 component was correlated with worse outcomes in the following domains: full-scale IQ (r=-0.709, p=0.015), performance IQ (r=-0.673, p=0.023) and fine motor skills (r=-0.654, p=0.029). While aberrancy in the P150 component was also correlated with math achievement (r=-0.065, p=0.028) and reading comprehension (r=-0.603, p=0.036), significant correlations were also found between math achievement and mother and father’s highest level of education, and between reading comprehension and mother’s highest level of education and household income. There was no correlation, however, between any demographic variables and full-scale IQ or performance IQ. Various socioeconomic factors were found to correlate with math and reading achievement, but not IQ or motor skills.Conclusion:Brain activity measured at infancy has predictive value for eventual neurocognitive outcome, with greater deviation from normal being associated with greater IQ deficits. Early ERP assessment may help manage patient expectations about neurocognitive outcomes following intervention.

Recognition memory for pictures in children with ADHD: An event-related potential study

Objective: Children with ADHD are reported to accompany by various degrees of recognition memory cognitive deficits. We aimed to investigate age-related changes of the amplitude in event-related potential recordings on recognition memory in Chinese children with ADHD and to provide theoretical basis of neuro-electrophysiology for the cognition development of children. Method: ERP and behavioral data of 6-to-10-year-old children with ADHD (n = 94) and typically developing controls (TD, n = 96) were collected while the children performed a classical visual study-test paradigm task. Results: Children with ADHD have defects in pictures recognition and showed a significantly smaller P2 component than that of TD children. The development of P2 and P3 component were different between the two groups. Moreover, the TD children showed the frontal old/new effect (N2) taken as a correlate of familiarity at 6 years old, and a parietal old/new effect (P3) taken as a correlate of recollection at 9 years old, while children with ADHD showed a parietal old/new effect (P3) only at 6 years old. Conclusion: Our study provided the novel evidence that recognition memory follow different developmental trajectories at the age of 6-10 between TD and ADHD.

Inhibition of the occipital face area modulates the electrophysiological signals of face familiarity: A combined cTBS-EEG study

The occipital face area (OFA) is hierarchically one of the first stages of the face processing network. It has originally been thought to be involved in early, structural processing steps, but currently more and more studies challenge this view and propose that it also takes part in higher level face processing, such as identification and recognition. Here we tested whether the OFA is involved in the initial steps of recognition memory and plays a causal role in the differential processing of familiar and unfamiliar faces. We used an offline, inhibitory continuous theta-burst stimulation (cTBS) protocol over the right OFA and the vertex as control site. Electroencephalographic (EEG) recording of event-related potentials (ERPs), elicited by visually presented familiar (famous) and unfamiliar faces was performed before and after stimulation. We observed a difference in ERPs for famous and unfamiliar faces in a time-window corresponding to the N250 component. Importantly, this difference was significantly increased by cTBS of the right OFA, suggesting its causal role in the differential processing of familiar and unfamiliar faces. The enhancement occurred focally, at electrodes close to the right hemispheric cTBS site, as well as over similar occipito-temporal sites of the contralateral hemisphere. To the best of our knowledge, this is the first study showing the causal role of the rOFA in the differential processing of familiar and unfamiliar faces, using combined cTBS and EEG recording methods. These results are discussed with respect to the nature of familiar face representations, supported by an extensive, bilateral network.

Event related potentials in children with internet addiction disorder

IntroductionInternet addiction disorder (IAD) is defined as one of the commonest disorder in children and adolescents affecting 40 percent of them. Although it does not cause mental disorders it is known that IAD is commonly related with attention deficit and hyperactivity disorder (ADHD). The best approach to asses attention is recording of event related potentials (ERPs) especially late response like P300. There are growing evidence regarding assessment of attention in IAD with different questionnaires but less is known about evidence received with more valid measurements like P300.ObjectivesThe aim of our study was to measure attention parameters in IAD subjects by using the most valid test–latency and amplitude of P300. We have examined 70 children with IAD aged 5-18 years. Children were divided into two groups: Group 1 (40 children) was matched as a study group including children with IAD and group 2 controls (30 children) without IAD and without ADHD.MethodsIAD was assessed by Young IAD scale. Children with Young scale less than 20 and with IQ less than 85 were excluded from the study. Recording of P300 was done by international protocol using oddball paradigm method. Statistical analysis was done by SSPS 26.ResultsIn study group increase in P300 latency was found (mean range 350-375 msc) while amplitude was normal (p &lt;0.05). In controls both parameters were within normal range.ConclusionsIAD could be related with attention disorders causing poor attention span. This evidence is very important as they affect internet addicted children and adolescents’ social well being.DisclosureNo significant relationships.

The interactive effects of reward expectation and emotional interference on cognitive conflict control: An ERP study

The effects of reward expectation and task-irrelevant emotional content on performance and event-related potential (ERP) recordings in a cognitive conflict control task were investigated using the face-word Stroop paradigm. A precue indicating additional monetary rewards for fast and accurate responses during the upcoming trial (incentive condition; relative to a cue indicating no additional reward, i.e., nonincentive condition) was followed by the presentation of target Chinese words (male vs. female) superimposed on background emotional faces (happy vs. fearful). The face's gender was congruent or incongruent with the target Chinese words. ERP results revealed that incentive cues elicited larger P1, P3, and CNV responses compared to nonincentive cues. There was a significant three-way interaction of reward expectation, emotional content, and congruency during the target processing stage such that emotionality and congruency interacted to affect the N170 and N2 component responses during the nonincentive condition but not during the incentive condition. These results indicate that reward-induced motivation reduces the interference effect of task-irrelevant emotional information, leading to better conflict resolution.

Arithmetic processing in children with dyscalculia: an event-related potential study.

IntroductionDyscalculia is a specific learning disorder affecting the ability to learn certain math processes, such as arithmetic data recovery. The group of children with dyscalculia is very heterogeneous, in part due to variability in their working memory (WM) deficits. To assess the brain response to arithmetic data recovery, we applied an arithmetic verification task during an event-related potential (ERP) recording. Two effects have been reported: the N400 effect (higher negative amplitude for incongruent than for congruent condition), associated with arithmetic incongruency and caused by the arithmetic priming effect, and the LPC effect (higher positive amplitude for the incongruent compared to the congruent condition), associated with a reevaluation process and modulated by the plausibility of the presented condition. This study aimed to (a) compare arithmetic processing between children with dyscalculia and children with good academic performance (GAP) using ERPs during an addition verification task and (b) explore, among children with dyscalculia, the relationship between WM and ERP effects.Materials and MethodsEEGs of 22 children with dyscalculia (DYS group) and 22 children with GAP (GAP group) were recorded during the performance of an addition verification task. ERPs synchronized with the probe stimulus were computed separately for the congruent and incongruent probes, and included only epochs with correct answers. Mixed 2-way ANOVAs for response times and correct answers were conducted. Comparisons between groups and correlation analyses using ERP amplitude data were carried out through multivariate nonparametric permutation tests.ResultsThe GAP group obtained more correct answers than the DYS group. An arithmetic N400 effect was observed in the GAP group but not in the DYS group. Both groups displayed an LPC effect. The larger the LPC amplitude was, the higher the WM index. Two subgroups were found within the DYS group: one with an average WM index and the other with a lower than average WM index. These subgroups displayed different ERPs patterns.DiscussionThe results indicated that the group of children with dyscalculia was very heterogeneous and therefore failed to show a robust LPC effect. Some of these children had WM deficits. When WM deficits were considered together with dyscalculia, an atypical ERP pattern that reflected their processing difficulties emerged. Their lack of the arithmetic N400 effect suggested that the processing in this step was not useful enough to produce an answer; thus, it was necessary to reevaluate the arithmetic-calculation process (LPC) in order to deliver a correct answer.ConclusionGiven that dyscalculia is a very heterogeneous deficit, studies examining dyscalculia should consider exploring deficits in WM because the whole group of children with dyscalculia seems to contain at least two subpopulations that differ in their calculation process.