Previous Event-related Potential Studies Research Articles

The use of the differential outcomes procedure for the recognition of facial expressions of complex emotions and its electrophysiological correlates.

The differential outcomes procedure (DOP) is an easily applicable method for enhancing discriminative learning and recognition memory. Its effectiveness in improving the recognition of facial expressions of emotion has been recently explored, with mixed success. This study aims to explore whether the expectancies generated via the DOP are reflected as differences in event-related potentials (ERPs) between participants in differential (DOP) or non-differential conditions (NOP) in a facial expression of complex emotion label task. Participants (n = 27 total, 14 DOP) in the DOP group received a specific reward for each specific emotion, while those in the NOP group received a random reinforcer when they correctly identified the emotion. We did not find differences in participants' accuracy or reaction time depending on group (DOP or NOP). These findings suggest that the DOP may not provide significant benefits for tasks involving labeling complex emotional expressions. However, differences in ERP components were observed between both groups. Specifically, the NOP group showed an increased Late Positive Component during encoding, fronto-central P300 during memory maintenance of facial stimuli, and frontal, fronto-central, and central P300 during retrieval. These ERPs, taken together, suggest that the task was more attentionally demanding for the NOP group. Additionally, some markers identified in previous ERP studies on the DOP were absent, indicating that the outcome expectancies may not have been fully generated. Finally, there were also interactions between the valence of the facial stimuli, participant group, and some of the potentials, such as N100 or N200 during encoding. These findings suggest that participants in the DOP group may have allocated more attentional resources to processing expressions of positive-valence emotions during earlier stages, possibly due to reward expectancy effects.

Processing of Shakespearean functional shift as a semantic anomaly in L2 English: Evidence from an ERP study

Functional shift, a productive word formation in English, converts the functional status of a word without changing its form. A previous event-related potential study reported that functional shift elicited left anterior negativity (LAN) and P600 effects in first language processing, suggesting that shifted words triggered syntactic processes in native English speakers. Using the same materials and experimental methods, this study investigated the processing of functional shift in English as a second language, asking Korean learners of English to make acceptability judgments of sentences containing a functional shift, a semantic incongruity, a double violation, or no violation. The results revealed that functional shift elicited significant N400 effects, indicating that Korean participants processed functionally shifted words as semantic anomalies. Our finding points to the possibility that the mental representation of functional shift differs in L1 and L2.

Variations in ERP data quality across paradigms, participants, and scoring procedures.

Although it is widely accepted that data quality for event-related potential (ERP) components varies considerably across studies and across participants within a study, ERP data quality has not received much systematic analysis. The present study used a recently developed metric of ERP data quality- the standardized measurement error (SME)-to examine how data quality varies across different ERP paradigms, across individual participants, and across different procedures for quantifying amplitude and latency values. The EEG recordings were taken from the ERP CORE, which includes data from 40 neurotypical college students for seven widely studied ERP components: P3b, N170, mismatch negativity, N400, error-related negativity, N2pc, and lateralized readiness potential. Large differences in data quality were observed across the different ERP components, and very large differences in data quality were observed across participants. Data quality also varied depending on the algorithm used to quantify the amplitude and especially the latency of a given ERP component. These results provide an initial set of benchmark values that can be used for comparison with previous and future ERP studies. They also provide useful information for predicting effect sizes and statistical power in future studies, even with different numbers of trials. More broadly, this study provides a general approach that could be used to determine which specific experimental designs, data collection procedures, and data processing algorithms lead to the best data quality.

Measuring Task-Related Brain Activity With Event-Related Potentials in Dynamic Task Scenario With Immersive Virtual Reality Environment.

Measurement of event-related potentials (ERPs) in simulated and real environments is advantageous for understanding cognition and behavior during practice of goal-directed activities. Recently, instead of using task-irrelevant “probe stimuli” to elicit ERPs, extraction of ERPs directly from events that occur in simulated and real environments has drawn increased attention. Among the previous ERP studies using immersive virtual reality, only a few cases elicited ERPs from task-related events in dynamic task settings. Furthermore, as far as we surveyed, there were no studies that examined the source of ERPs or correlation between ERPs and behavioral performance in 360-degree immersive virtual reality using head-mounted display. In this study, EEG signals were recorded from 16 participants while they were playing the first-person shooter game with immersive virtual reality environment. Error related negativity (ERN) and correct-(response)-related negativity (CRN) elicited by shooting-related events were successfully extracted. We found the ERN amplitudes to be correlated with the individual shooting performance. Interestingly, the main source of the ERN was the rostral anterior cingulate cortex (ACC), which is different from previous studies where the signal source was often estimated to be the more caudal part of ACC. The obtained results are expected to contribute to the evaluation of cognitive functions and behavioral performance by ERPs in a simulated environment.

Repetitive Religious Chanting Invokes Positive Emotional Schema to Counterbalance Fear: A Multi-Modal Functional and Structural MRI Study.

IntroductionDuring hard times, religious chanting/praying is widely practiced to cope with negative or stressful emotions. While the underlying neural mechanism has not been investigated to a sufficient extent. A previous event-related potential study showed that religious chanting could significantly diminish the late-positive potential induced by negative stimuli. However, the regulatory role of subcortical brain regions, especially the amygdala, in this process remains unclear. This multi-modal MRI study aimed to further clarify the neural mechanism underlying the effectiveness of religious chanting for emotion regulation.MethodologyTwenty-one participants were recruited for a multi-modal MRI study. Their age range was 40–52 years, 11 were female and all participants had at least 1 year of experience in religious chanting. The participants were asked to view neutral/fearful pictures while practicing religious chanting (i.e., chanting the name of Buddha Amitābha), non-religious chanting (i.e., chanting the name of Santa Claus), or no chanting. A 3.0 T Philips MRI scanner was used to collect the data and SPM12 was used to analyze the imaging data. Voxel-based morphometry (VBM) was used to explore the potential hemispheric asymmetries in practitioners.ResultsCompared to non-religious chanting and no chanting, higher brain activity was observed in several brain regions when participants performed religious chanting while viewing fearful images. These brain regions included the fusiform gyrus, left parietal lobule, and prefrontal cortex, as well as subcortical regions such as the amygdala, thalamus, and midbrain. Importantly, significantly more activity was observed in the left than in the right amygdala during religious chanting. VBM showed hemispheric asymmetries, mainly in the thalamus, putamen, hippocampus, amygdala, and cerebellum; areas related to skill learning and biased memory formation.ConclusionThis preliminary study showed that repetitive religious chanting may induce strong brain activity, especially in response to stimuli with negative valence. Practicing religious chanting may structurally lateralize a network of brain areas involved in biased memory formation. These functional and structural results suggest that religious chanting helps to form a positive schema to counterbalance negative emotions. Future randomized control studies are necessary to confirm the neural mechanism related to religious chanting in coping with stress and negative emotions.

Attentional capture by a color singleton is stronger at spatially relevant than irrelevant locations: Evidence from an ERP study.

Top-down spatial attention can modulate contingent attentional capture, but the underlying mechanism is still not clear. Using variants of spatial cueing paradigms, our previous event-related potential study showed that peripheral color singleton cues with task-relevant features captured attention (indexed by cue-elicited N2pc) even when the targets appeared at central locations, but the magnitude of attentional capture was smaller than when the targets appeared at same peripheral locations. One reasonable explanation is that the modulation effect is due to spatial relevance of cues. However, several other confounding factors might also explain the modulation effect, such as task difficulty, spread of attentional window, and inside/outside relation between cue and attentional window. In the present study, we rearranged the relative locations between cues and targets to control these factors and to further examine whether inequivalence of attentional capture across attended and unattended locations was a common phenomenon. In two experiments, color singleton cues elicited apparent N2pc components when participants were searching for targets possessing the same color, which replicated typical findings of contingent attentional capture. More importantly, the modulation effect of top-down spatial attention on the cue-elicited N2pc still existed even when the factors of task difficulty (Experiment 1), spread of attentional window (Experiment 1), or inside/outside relation between cue and attentional window (Experiment 2) were controlled. These results consistently demonstrate that attentional capture by a color singleton is stronger at spatially relevant locations than at spatially irrelevant locations, suggesting an important role of spatial relevance on contingent attentional capture.

P300 response modulation reflects breaches of non-probabilistic expectations

In oddball paradigms, infrequent stimuli elicit larger P300 event related potentials (ERPs) than frequent ones. One hypothesis is that P300 modulations reflect the degree of “surprise” associated with unexpected stimuli. That is the P300 represents how unlikely the stimulus is and this signal is then used to update the observer’s expectations. It could be hypothesized that P300 is modulated by any factor affecting an observer’s expectations, not only target probability. Alternatively, the P300 may reflect an evaluative process engaged whenever a discrepancy between task context and sensory inputs arises, irrespective of the latter probability. In previous ERP studies, stimulus probability was often the only determinant of task set confounding the effects of stimulus probability and set stimulus discrepancy. In this study, we used a speeded luminance detection task. The target was preceded by a central cue that predicted its location. The probability that the target was valid, i.e. would appear at the cued location was manipulated by varying the reliability of the cue. Reaction times were modulated by probabilistic expectations based on cue reliability and target validity while P300 was affected by target validity only. We conclude that increased P300 amplitude reflects primarily breaches of non-probabilistic expectations, rather than target probability.

Blurring attenuates the early posterior negativity in response to snake stimuli

Previous event-related potential studies have reported enhanced Early Posterior Negativity (EPN) in response to snake pictures compared to pictures of other animals. This EPN snake effect may be partly driven by specific snake skin patterns. In this study, by using blurred pictures to make these patterns less visible, we explored whether the relative absence of such local features will attenuate the EPN snake effect. Non-blurred and blurred pictures of snakes, spiders, and birds were presented in a rapid serial visual presentation paradigm with a rate of three pictures per second. The EPN mean activity was extracted from the 225–330 ms time frame after stimulus onset at the parietal-occipital cluster (PO3, O1, Oz, O2, PO4). The results show an enhanced EPN in response to snake pictures compared to spider and bird pictures. Non-blurred snake pictures elicited much larger EPN amplitudes than blurred snake pictures, suggesting that the EPN is larger for snake pictures when the local features of the snake skin are clearly visible. Yet, blurred snake pictures elicited higher EPN amplitudes when compared to blurred spider and bird pictures, suggesting a complementary role for the more global features of snakes. Spatial frequency analysis of the stimuli indicated excess energy for high spatial frequencies in non-blurred snake compared to spider and bird pictures.

Abnormal frontal generator during auditory sensory gating in panic disorder: An MEG study

Patients with panic disorder (PD) exhibit abnormalities in early-stage information processing, even for the nonthreatening stimuli. A previous event-related potential study reported that PD patients show a deficit in sensory gating (SG), a protective mechanism of the brain to filter out irrelevant sensory inputs. However, there is no clear understanding about the neural correlates of SG deficits in PD. Moreover, whether SG deficits, if any, are associated with clinical manifestations remain unknown. In this study, 18 patients with PD and 20 age- and gender-matched healthy controls were recruited to perform auditory paired-stimulus paradigm using magnetoencephalographic (MEG) recordings. Results showed that PD patients demonstrated significantly higher M50 SG ratios in the right inferior frontal gyrus (RIFG) and higher M100 SG ratios in both RIFG and right superior temporal gyrus (RSTG) than those of the control group. It was important to note that in the RIFG, the M50 SG ratios correlated significantly with the scores of Body Sensation Questionnaire (BSQ) and Distractibility scale of Sensory Gating Inventory among patients with PD. In conclusion, this study suggests that PD patients exhibited a deficient ability to filter out irrelevant information, and such a defect might lead to cognitive misinterpretation of somatic sensations and distractibility.

Involuntary Attention Restoration During Exposure to Mobile-Based 360° Virtual Nature in Healthy Adults With Different Levels of Restorative Experience: Event-Related Potential Study.

BackgroundWith the global trend of urbanization, there are increasing reports of a possible association between decreased exposure to nature and increased occurrence of mental disorders. New 360° virtual reality (VR) technology using smartphones and portable VR glasses can overcome spatial and temporal limitations to help people deal with mental fatigue in everyday life.ObjectiveOn the basis of attention restoration theory (ART), this study aimed to investigate whether the amplitude of the mismatch negativity (MMN)/P3a complex could act as an event-related potential (ERP) biomarker of involuntary attention restoration during exposure to 360° virtual nature in healthy young adults with different levels of restorative VR experience.MethodsA total of 40 healthy adults completed prequestionnaires on demographics and simulator sickness and postquestionnaires on simulator sickness and perceived restorativeness before and after exposure to virtual nature, respectively. During the VR exposure, brain activity was measured by electroencephalography as participants were asked to conduct a 2-tone passive auditory oddball task.ResultsThe amplitude and latency of the MMN/P3a complex were compared between individuals reporting a highly restorative experience and those reporting a less restorative experience. Although viewing a virtual nature environment, the high restorative group (N=19) exhibited significantly reduced P3a amplitudes compared with the low restorative group (N=20; t38=2.57; P=.02; d=0.59). Particularly, a moderate but significant negative correlation was found between the self-reported restorativeness scores and the P3a amplitudes at the fronto-central region (r=−.38; P=.02). However, the latency of the MMN/P3a complex did not significantly differ between the 2 groups (auditory mismatch negativity: t38=−1.47; P=.15 and P3a: t38=−0.31; P=.76).ConclusionsConsidering individuals’ restorative experience, the amplitude of the fronto-central MMN/P3a complex can potentially be employed as a distinct ERP component of interest in involuntary attention restoration during virtual nature experience in healthy young adults. The findings for the 360° virtual nature experience seem to be consistent with those of previous ERP studies on the effects of meditation practice. This study extends the findings of previous ART and ERP studies of real-world meditation, restoration, and mental fatigue management into the virtual world created by mobile phone–based VR glasses and 360° video content.

Gulf War illness associated with abnormal auditory P1 event-related potential: Evidence of impaired cholinergic processing replicated in a national sample

Our team previously reported event-related potential (ERP) and hyperarousal patterns from a study of one construction battalion of the U.S. Naval Reserve who served during the 1991 Persian Gulf War. We sought to replicate these findings in a sample that was more representative of the entire Gulf War-era veteran population, including male and female participants from four branches of the military. We collected ERP data from 40 veterans meeting Haley criteria for Gulf War syndromes 1–3 and from 22 matched Gulf War veteran controls while they performed an auditory oddball task. Reports of hyperarousal from the ill veterans were significantly greater than those from the control veterans, and P1 amplitudes in Syndromes 2 and 3 were significantly higher than P1 amplitudes in Syndrome 1, replicating our previous findings. Many of the contributors to the generation of the P1 potential are also involved in the regulation of arousal and are modulated by cholinergic and dopaminergic systems—two systems whose dysfunction has been implicated in Gulf War illness. These differences among the three syndrome groups where their means were on either side of controls is a replication of our previous ERP study and is consistent with previous imaging studies of this population.

An ERP Study on the Processing of Chinese Applied-Object Structures

AbstractVerb-argument relation is a very important aspect of syntax-semantics interaction in sentence processing. Previous ERP (event related potentials) studies in this field concentrated on the relation between the verb and its core arguments. The present study aims to reveal the ERP pattern of Chinese applied object structures (AOSs), in which a peripheral argument is promoted to occupy the position of the patient object, as compared with the patient object structures (POSs). The ERP data were collected when participants were asked to perform acceptability judgments about Chinese phrases. The result shows that, similar to the previous studies of number-of-argument violations, Chinese AOSs show a bilaterally distributed N400 effect. But different from all the previous studies of verb-argument relations, Chinese AOSs demonstrate a sustained anterior positivity (SAP). This SAP, which is very rare in the studies related to complexity of argument structure operation, reflects the integration difficulty of the newly promoted arguments and the progressive nature of well-formedness checking in the processing of Chinese AOSs which is in accordance with the metonymic mechanism of non-patient objects in the relevant cognitive study. It shows that, in Chinese, which is a paratactic language, semantics (thematic roles) plays a more important role in the syntax-semantics interface than that in hypotactic languages.

Electrophysiological Responses to Expectancy Violations in Semantic and Gambling Tasks: A Comparison of Different EEG Reference Approaches.

Dynamically evaluating the outcomes of our actions and thoughts is a fundamental cognitive ability. Given its excellent temporal resolution, the event-related potential (ERP) technology has been used to address this issue. The feedback-related negativity (FRN) component of ERPs has been studied intensively with the averaged linked mastoid reference method (LM). However, it is unknown whether FRN can be induced by an expectancy violation in an antonym relations context and whether LM is the most suitable reference approach. To address these issues, the current research directly compared the ERP components induced by expectancy violations in antonym expectation and gambling tasks with a within-subjects design and investigated the effect of the reference approach on the experimental effects. Specifically, we systematically compared the influence of the LM, reference electrode standardization technique (REST) and average reference (AVE) approaches on the amplitude, scalp distribution and magnitude of ERP effects as a function of expectancy violation type. The expectancy deviation in the antonym expectation task elicited an N400 effect that differed from the FRN effect induced in the gambling task; this difference was confirmed by all the three reference methods. Both the amplitudes of the ERP effects (N400 and FRN) and the magnitude as the expectancy violation increased were greater under the LM approach than those under the REST approach, followed by those under the AVE approach. Based on the statistical results, the electrode sites that showed the N400 and FRN effects critically depended on the reference method, and the results of the REST analysis were consistent with previous ERP studies. Combined with evidence from simulation studies, we suggest that REST is an optional reference method to be used in future ERP data analysis.

Sex Differences in Categorical Adaptation for Faces and Chinese Characters during Early Perceptual Processing.

Previous event-related potential studies support sex differences in the N170 response during face and word processing; however, it remains unclear whether N170 categorical adaptation for faces and words is different between women and men. Using an adaptation paradigm, in which an adaptor and subsequent test stimulus are presented during each trial, the present study investigated N170 categorical adaptation for faces and Chinese characters in both women and men. The results demonstrated that the N170 amplitude elicited by test stimuli in within-category condition was lower than in control category condition, and this was observed during both face and Chinese character processing in women and men. In addition, we found that men have greater N170 categorical adaptation for face and word processing than women. There was also a significant correlation between N170 categorical adaptation indices for face and Chinese character processing in men, which did not occur in women. These findings suggest that men and women process repeated faces or words differently.

P 135 Using a BCI approach to record ERPs for detecting signs of awareness in patients with severe disorders of consciousness

Objective In the clinical setting mainly behavioral methods are used for differentiating between patients with unresponsive wakefulness syndrome (UWS) and minimally consciousness syndrome (MCS). These may result in a high rate of false negative classifications, as some patients cannot produce clear behavioral responses, although they are conscious. To increase diagnostic objectivity additional methods to assess patients” states of consciousness are needed. FMRI methods have proven useful, but are costly and rarely available. Building up on previous ERP (event related potential ) studies in patients with severe disorders of consciousness ( Neumann and Kotchoubey, 2004 ) we tested an ERP measurement system based on brain-computer interface (BCI) technology (mindbeagle, g.tec, Schiedlberg) as patient bedside instrument to detect consciousness under exclusion of behavioral response requirements. Methods Recordings were performed in 13 patients with severe disorders of consciousness(5MCS, 8UWS), as diagnosed by the Coma Recovery Scale revised (CRSr). The BCI testing consisted of two subtests, an auditory and vibro-tactile paradigm. For both subtests patients were instructed to react to a rare target stimulus and to neglect an often occurring non-target stimulus. Accordingly the subtests combine the passive (Oddball structure) and the active (instruction to react to target stimulus) paradigm. In the auditory subtest two distinct pure tones (500 Hz and 1000 Hz) were presented on both ears. In the vibro-tactile subtest vibration via vibro-tactile trajectories was either transported to the patients left (target) or right (non-target) wrist. The accuracy level at which a non-target and target could be differentiated by the system classifier, trained on the patient’s P300 response, was used as an outcome measure. Results With exception of two patients (one in UWS and one in MCS ) all participants showed an accuracy level above chance (12.5%) in at least one of the subtests. In the auditory subtest this was true for two patients with MCS (20%, 30%) and three with UWS (100%, 30%, 80%). In the vibro-tactile subtest for three patients with MCS (40%, 20%, 20%) and four patients with UWS (50%, 20%, 60%, 60%) the target vs. non-target discrimination could be made. Conclusion Although there are still improvements necessary to use the applied system as a diagnostic instrument in the clinical setting (e.g. adaptations to the clinical population, precise manual for standardized testing), we were able to detected signs of awareness in patients that were not accessible by behavioral measurements. Additional research is needed to determine validity and significance of that finding.

The costs of target prioritization and the external requirements for using a recall-to-reject strategy in memory exclusion tasks: a meta-analysis.

In event-related potential (ERP) studies, the left-parietal old/new effect is commonly considered as a neural correlate of recollection. In memory exclusion tasks, the effect is usually observed when the targeted information is identified, but it is not necessarily present when studied items are rejected as nontargets. Interestingly, both the presence and the absence of such old/new effects to nontargets have been regarded as indicator for strategic retrieval. We reviewed previous ERP studies using memory exclusion tasks to analyze the reaction time (RT) pattern in such studies, as well as the influence of task difficulty on the occurrence of nontarget retrieval. We identified 44 test conditions, reported in 24 studies, and subjected the behavioral data to a meta-analysis. The RTs to correctly rejected new items were shorter than the RTs to hits, in particular in studies that required differentiating conceptual or perceptual information at test. When the retrieval of target information was prioritized, RTs to nontargets were delayed relative to targets. Without such prioritization, no such RT differences were observed. For test conditions with nontarget retrieval, the retrieval accuracy was poorer compared with test conditions without such retrieval. The findings support previous studies that claimed that nontarget retrieval becomes more likely when target retrieval is difficult, but the strong overlap in task difficulty between conditions with and without nontarget retrieval indicates that other, partly yet to-be-identified factors contribute to the occurrence of nontarget retrieval as well.

An ERP Study of Response Inhibition in the Auditory Domain in Children with Fetal Alcohol Spectrum Disorders.

Previous event-related potential (ERP) studies of response inhibition in children with fetal alcohol spectrum disorder (FASD) have used a visual Go/NoGo task to study the impact of prenatal alcohol exposure on response inhibition. No studies exist using auditory versions of the task; thus, it is unclear how the deficits observed in visual tasks translate into the auditory domain. This study examined ERPs using an auditory Go/NoGo paradigm in a sample of 35 school-age children-18 with heavy prenatal alcohol exposure and 17 normally developing controls. Alcohol-exposed children performed as well as controls in terms of inhibiting their responses; however, their reaction times were significantly slower under the Go condition. As in the ERP visual Go/NoGo task previously administered to these children, group differences were seen in early perceptual processing, specifically related to stimulus discrimination, with a decrease in P2 amplitude in the alcohol-exposed group. The control group exhibited greater N2 amplitude in the NoGo compared to the Go condition while the alcohol-exposed group did not, suggesting a group difference in the neural substrates underlying conflict monitoring. The alcohol-exposed group demonstrated longer latency P3 with reduced amplitude, suggesting poorer allocation of attention. The alcohol-exposed group also exhibited a late positive component (LPC) similar to the one observed in the previous visual ERP study. This LPC may indicate compensatory neurophysiological function related to resetting of attentional control networks in preparation for the next trial. None of the ERP outcomes in this study were related to potential confounders which included cognitive and socioeconomic measures as well as ADHD diagnosis. The observed ERP group differences point to elements of perceptual and attentional processing likely to be involved in the performance deficits often observed in children with FASD. We also observed changes in ERPs related to conflict monitoring/response inhibition, highlighting fetal alcohol-related effects on how the brain responds when there is need to identify and respond to environmental cues by switching away from a prepotent motor response to an inhibited state.

Sex differences of hemispheric lateralization for faces and Chinese characters in early perceptual processing

Previous event-related potential studies showed that the N170 response is left-lateralized for words and right-lateralized for faces. Using a one-back repetition task, this study aimed to clarify sex differences in hemispheric specialization for both faces and words in early visual processing. We found that the N170 amplitude elicited by faces in males was right-lateralized, while in females it was bilateral. Interestingly, the N170 amplitude elicited by Chinese characters in males was bilateral, whereas in females it was left-lateralized. The N170 latency for faces was shorter in females than in males, whereas the N170 latency for Chinese characters was similar in females and males. The degree of lateralization of faces was significantly related to the degree of lateralization of Chinese characters in both the female and male groups. Therefore, sex differences in N170 hemispheric lateralization for faces are different from those for Chinese characters, and there are some links between the two categories of objects of expertise in early perceptual processing.

A longitudinal event-related potential study of selective serotonin reuptake inhibitor therapy in treatment-naïve pediatric obsessive compulsive disorder patients.

Obsessive-compulsive disorder (OCD) is characterized by obsessive thoughts and/or compulsive behaviors, involving specific cognition and/or information processing disorders. Event-related potentials (ERPs) are commonly used as physiological measures of cognitive function. In conscious patients, ERPs are easily and non-invasively measured. Previous ERP studies have revealed differences between OCD patients and control subjects. Whether ERPs reflect the pharmacological effects of OCD treatment, particularly in treatment-naïve pediatric patients, remains unknown. We used the Child's Yale-Brown Obsessive-Compulsive Scale (CY-BOCS) to evaluate the symptomatic severity of 12 treatment-naïve pediatric OCD patients. Comparisons were made with 12 age-, sex-, and intelligence-matched controls. The P300 and mismatch negativity (MMN) components were measured during an auditory odd-ball task at baseline in both groups and after the 3-year serotonin reuptake inhibitor (SSRI) treatment in OCD patients. Compared with controls, P300 amplitudes were smaller n the OCD group at Fz, Cz, Pz, C3, and C4. After SSRI treatment, P300 amplitudes increased partly at Fz and C4 in association with symptomatic improvements. We found a significant positive correlation between P300 amplitude in C4 and CY-BOCS scores. Our findings confirm the utility of SSRIs in pediatric OCD, and suggest the utility of ERPs for evaluating pharmacological effects in treatment-naïve pediatric OCD patients.

Prosody–syntax integration in a second language: Contrasting event-related potentials from German and Chinese learners of English using linear mixed effect models

The role of prosodic information in sentence processing is not usually addressed in second language (L2) instruction, and neurocognitive studies on prosody–syntax interactions are rare. Here we compare event-related potentials (ERP) of Chinese and German learners of English L2 to those of native English speakers and show how first language (L1) background and L2 proficiency influence the online processing of prosody-induced garden-path effects. Unlike most previous ERP studies, we use linear mixed effect models to analyse L2 proficiency as a continuous (rather than categorical) variable. Our results show that both L1 background and language proficiency shape the integration of prosodic and syntactic cues, and that, importantly, even English native speakers’ ERPs were influenced by their English proficiency level. Lastly, this article also addresses why coverage of prosody in L2 classroom instruction may be beneficial.