Event-related Potential Responses Research Articles

Cannabidiol-enriched oil for adult patients with drug-resistant epilepsy: Prospective clinical and electrophysiological study.

Cannabidiol-enriched oil (CBDO) is being used increasingly to improve seizure control in adult patients with drug-resistant epilepsy (DRE), despite the lack of large-scale studies supporting its efficacy in this patient population. We aimed to assess the effects of add-on CBDO on seizure frequency as well as on gait, cognitive, affective, and sleep-quality metrics, and to explore the electrophysiological changes in responder and non-responder DRE patients treated with add-on CBDO. We prospectively recruited adult DRE patients who were treated with add-on CBDO. Patients were evaluated prior to treatment and following 4 weeks of a maintenance daily dose of ≈260 mg CBD and ≈12 mg Δ9-tetrahydrocannabinol (THC). The outcome measures included seizure response to CBDO (defined as ≥50% decrease in seizures compared to pre-CBDO baseline), gait testing, Montreal Cognitive Assessment (MoCA), Hospital Anxiety and Depression Scale (HADS), and sleep-quality questionnaire assessments. Patients underwent electroencephalography (EEG) recording during rest as well as event-related potentials (ERPs) during visual Go/NoGo task while sitting and while walking. Nineteen patients were recruited, of which 16 finished pre- and post-CBDO assessments. Seven patients (43.75%) were responders demonstrating an average reduction of 82.4% in seizures, and nine patients (56.25%) were non-responders with an average seizure increase of 30.1%. No differences in demographics and clinical parameters were found between responders and non-responders at baseline. However, responders demonstrated better performance in the dual-task walking post-treatment (p = .015), and correlation between increase in MoCA and seizure reduction (r = .810, p = .027). Post-CBDO P300 amplitude was lower during No/Go-sitting in non-responders (p = .028) and during No/Go-walking in responders (p = .068). CBDO treatment can reduce seizures in a subset of patients with DRE, but could aggravate seizure control in a minority of patients; yet we found no specific baseline clinical or electrophysiological characteristics that are associated with response to CBDO. However, changes in ERPs in response to treatment could be a promising direction to better identify patients who could benefit from CBDO treatment.

Pain reflects the informational value of nociceptive inputs.

Pain perception and its modulation are fundamental to human learning and adaptive behavior. This study investigated the hypothesis that pain perception is tied to pain's learning function. Thirty-one participants performed a threat conditioning task where certain cues were associated with a possibility of receiving a painful electric shock. The cues that signaled potential pain or safety were regularly changed, requiring participants to continually establish new associations. Using computational models, we quantified participants' pain expectations and prediction errors throughout the task and assessed their relationship with pain perception and electrophysiological responses. Our findings suggest that subjective pain perception increases with prediction error, that is, when pain was unexpected. Prediction errors were also related to physiological nociceptive responses, including the amplitude of nociceptive flexion reflex and electroencephalography markers of cortical nociceptive processing (N1-P2-evoked potential and gamma-band power). In addition, higher pain expectations were related to increased late event-related potential responses and alpha/beta decreases in amplitude during cue presentation. These results further strengthen the idea of a crucial link between pain and learning and suggest that understanding the influence of learning mechanisms in pain modulation could help us understand when and why pain perception is modulated in health and disease.

Improved data quality and statistical power of trial-level event-related potentials with Bayesian random-shift Gaussian processes

Studies of cognitive processes via electroencephalogram (EEG) recordings often analyze group-level event-related potentials (ERPs) averaged over multiple subjects and trials. This averaging procedure can obscure scientifically relevant variability across subjects and trials, but has been necessary due to the difficulties posed by inference of trial-level ERPs. We introduce the Bayesian Random Phase-Amplitude Gaussian Process (RPAGP) model, for inference of trial-level amplitude, latency, and ERP waveforms. We apply RPAGP to data from a study of ERP responses to emotionally arousing images. The model estimates of trial-specific signals are shown to greatly improve statistical power in detecting significant differences in experimental conditions compared to existing methods. Our results suggest that replacing the observed data with the de-noised RPAGP predictions can potentially improve the sensitivity and accuracy of many of the existing ERP analysis pipelines.

This is me! Neural correlates of self-recognition in 6- to 8-month-old infants.

Historically, evidence of self-recognition in development has been associated with the "rouge test"; however, this has been often criticized for providing a reductionist picture of self-conscious behavior. With two event-related potential (ERP) experiments, this study investigated the origin of self-recognition. Six- to eight-month-old infants (42 males and 35 females, predominately White, tested in the UK in 2022-2023) were presented with images of their face, another peer's face, and their mother's face (N = 38, Exp.1), and images of their own face morphed into another peer's face (N = 39, Exp.2). Results showed an enhanced P100 in infants' ERP response to their own face compared to others' faces (Exp.1 only), suggesting the presence of an enhanced attentional mechanism to one own's face as early as 6 months.

"I heard it before … or not": time-course of ERP response and behavioural correlates associated with false recognition memory.

Electrophysiological and behavioural correlates of true and false memories were examined in the Deese/Roediger-McDermont (DRM) paradigm. A mass univariate approach for analysing event-related potentials (ERP) in the temporal domain was used to examine the electrophysiological effects associated with this paradigm precisely (point-by-point) and without bias (data-driven). Behaviourally, true and false recognition did not differ, and the predicted DRM effect was observed, as false recognition of critical lures (i.e., new words semantically related to studied words) was higher than false alarms of new (unrelated) words. Neurally, an expected old/new effect was observed during the time-range of the late positive component (LPC) over left centro-parietal scalp electrodes. Furthermore, true recognition also evoked larger LPC amplitudes than false recognition over both left centro-parietal and fronto-central scalp electrodes. However, we did not observe LPC-related differences between critical lures and new words, nor between correct rejections of critical lures and new words. In contrast, correct rejections of critical lures were accompanied by higher activation of a sustained positive slow wave (SPSW) in right fronto-central electrodes beyond 1200 ms. This result reveals a key role of post-retrieval processes in recognition. Results are discussed in light of theoretical approaches to false memory in the DRM paradigm.

Comparative study of event-related potential responses within syllables of intra and inter phoneme classes

The present study was carried out to assess the signature neural dynamics as evinced through event-related potential (ERP) responses of the P300 waveform across different inter and intra phoneme consonant classes and to quantify the differential neural dynamical response in real-time. The ERP responses to non-sense three-syllable consonantvowel transitions CVCVCV non-words were recorded on 26 healthy individuals of either sex with an age group of 18–25 years. The first syllable of the non-sense word was always fixed, and the ERP responses of the middle syllable were recorded at the phoneme level, and the ERP responses elicited by the middle syllable were evaluated. The results of the present study documented that different consonant phoneme classes (plosives, fricatives, affricatives, liquids, and nasals) elicited differential neural dynamical responses as observed through the P300 waveform response, exhibiting a significant difference in P300 waveform amplitude across the fricatives vs. nasals experimental design.

Effects of Simulated Airplane Cabin Noise on In-Flight Meal Perception in the Brain Using Electroencephalography.

Auditory distractions can impair the sensory evaluation of food; however, the specific impact of airplane cabin noise on the sensory perception of in-flight meals remains poorly studied. Here, we investigated the effects of airplane cabin noise on the visual processing of in-flight meal stimuli using electroencephalography (EEG) in twenty healthy male subjects. Resting-state EEG and event-related potential (ERP) responses to in-flight meal images were acquired during quiet and simulated cabin noise conditions. Participants reported mild discomfort and some loss of appetite when exposed to airplane cabin noise. The analysis of resting-state EEG showed an increase in the absolute power of theta and beta frequency bands in the left superior parietal and left frontal/right central regions under simulated cabin noise conditions, compared to quiet conditions. The ERP results showed that the amplitude of responses evoked by visual meal images in the superior parietal area was reduced in the noise condition compared to the quiet condition. Our findings suggest that airplane cabin noise disrupts the visual perception and attentional processing of in-flight food stimuli. These neural changes imply an impact on integrating sensory information, resulting in altered sensory evaluations of food during in-flight dining experiences.

Correlated P300b and phasic pupil-dilation responses to motivationally significant stimuli.

Motivationally significant events like oddball stimuli elicit both a characteristic event-related potential (ERPs) known as P300 and a set of autonomic responses including a phasic pupil dilation. Although co-occurring, P300 and pupil-dilation responses to oddball events have been repeatedly found to be uncorrelated, suggesting separate origins. We re-examined their relationship in the context of a three-stimulus version of the auditory oddball task, independently manipulating the frequency (rare vs. repeated) and motivational significance (relevance for the participant's task) of the stimuli. We used independent component analysis to derive a P300b component from EEG traces and linear modeling to separate a stimulus-related pupil-dilation response from a potentially confounding action-related response. These steps revealed that, once the complexity of ERP and pupil-dilation responses to oddball targets is accounted for, the amplitude of phasic pupil dilations and P300b are tightly and positively correlated (across participants: r = .69 p = .002), supporting their coordinated generation.

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.

N2 Responses in Youths With Psychosis Risk Syndrome and Their Association With Clinical Outcomes: A Cohort Follow-Up Study Based on the Three-Stimulus Visual Oddball Paradigm.

Schizophrenia often occurs during youth, and psychosis risk syndrome occurs before the onset of psychosis. The aim of this study was to determine whether the visual event-related potential responses in youths with psychosis risk syndrome were defective in the presence of interference stimuli and associated with their clinical outcomes. A total of 223 participants, including 122 patients with psychosis risk syndrome, 50 patients with emotional disorders, and 51 healthy control subjects, were assessed. Baseline EEG was recorded during the three-stimulus visual oddball task. The event-related potentials induced by square pictures with different colors were measured. Almost all patients with psychosis risk syndrome were followed up for 12 months and were reclassified into three subgroups: conversion, symptomatic, and remission. The differences in baseline event-related potential responses were compared among the clinical outcome subgroups. The average N2 amplitude of the psychosis risk syndrome group was significantly less negative than that in the healthy control group (d=0.53). The baseline average N2 amplitude in the conversion subgroup was significantly less negative than that in the symptomatic (d=0.58) and remission (d=0.50) subgroups and in the healthy control group (d=0.97). The average N2 amplitude did not differ significantly between the symptomatic and remission subgroups (d=0.02). However, it was significantly less negative in the symptomatic and remission subgroups than in the healthy control group (d=0.46 and d=0.38). No statistically significant results were found in the P3 response. Youths with psychosis risk syndrome had significant N2 amplitude defects in attention processing with interference stimuli. N2 amplitude shows potential as a prognostic biomarker of clinical outcome in the psychosis risk syndrome.

Neural correlates of processing active and passive sentences: proficiency-dependent event-related potential evidence in Chinese English foreign language learners.

We explored whether and to what extent the neural mechanisms of second language sentence processing resemble those of native speakers by investigating the temporal dynamics of syntactic processing in terms of active or passive voice in reading English sentences by Chinese English Foreign Language (EFL) learners with high or low English proficiency. Participants were divided into two groups based on their proficiency levels in English. Three types of sentences (active, passive and ungrammatical) were presented to participants when their event-related potential responses were recorded at the verbs and the final words. The results showed that high-proficiency participants exhibited a greater anterior negativity at the verb position for ungrammatical sentences compared to active sentences. Furthermore, passive sentences elicited a larger frontal positivity than active sentences at the final word position. Additionally, greater P600 effects were observed for both passive and ungrammatical sentences than active sentences at the final word. The low-proficiency group exhibited a greater anterior negativity at the verb (but not the final word) position. In conclusion, these findings emphasize the role of proficiency as a modulating factor in the processing of English active and passive sentences among Chinese EFL learners. Furthermore, the processing of English active and passive sentences by these learners can be conceptualized as a three-stage process: prediction, correction and integration, representing the underlying cognitive mechanisms. This study provides novel insights into the understanding of the cognitive mechanism involved in second language sentence processing.

Exploration of the influence of the quantification method and reference scheme on feedback-related negativity and standardized measurement error of feedback-related negativity amplitudes in a trust game

Various approaches have been taken over the years to quantify event-related potential (ERP) responses and these approaches may vary in their utility connecting empirical research and scientific claims. In this work we compared different quantification methods as well as the influence of three reference methods (linked mastoids, average reference, and current source density) on the resulting ERP amplitude. We use the experimental effects and effect sizes (Cohen's d) to evaluate the different methodological variants and we calculate intraclass correlation coefficients (ICC). In addition, the bootstrapped standard error of the means (SME, Luck et al., 2021), which was recently suggested as a quality criterion for ERP research, is used for this purpose. Our example for an ERP is the feedback-related negativity (FRN) to feedback about trustee behavior in a trust game with participants in the trustor position. We found that the quantification methods concerning the FRN influenced the absolute value of condition effects in the experimental paradigm. Yet, the patterns of effects were detected by all chosen methods, except for the ‘individual difference wave’-based peak window approach. In addition, our findings stress the importance of checking the reference electrodes concerning effects of the experimental conditions. Furthermore, interactions of topographical distribution and reference choice should be considered. Finally, we were able to show that the SME is lower for more datapoints that are given in the quantification period of the FRN, and higher for more negative FRN amplitudes. These biases may lead to divergence of SME and effect size detection. Therefore, if the SME was used to compare different processing choices one should consider controlling for these important aspects of the data and possibly include other quality criteria like effect sizes.

Cognition-Emotion Interaction during L2 Sentence Comprehension: The Correlation of ERP and GSR Responses to Sense Combinations.

This study mainly examined the role of the combination of three senses (i.e., auditory, visual, and tactile) and five senses (i.e., auditory, visual, tactile, olfactory, and gustatory) in the correlation between electrophysiological and electrodermal responses underlying second language (L2) sentence comprehension. Forty subjects did two acceptability judgment tasks, encompassing congruent and semantically/pragmatically incongruent sentences. The event-related potential (ERP) and galvanic skin response (GSR) data for both the target and final words of the sentences were collected and analyzed. The results revealed that there is an interaction between cognitive and emotional responses in both semantically and pragmatically incongruent sentences, yet the timing of the interaction is longer in sentences with pragmatic incongruity due to their complexity. Based on the ERP and GSR correlation results, it was further found that the five-sense combination approach improves L2 sentence comprehension and interest in learning materials yet reduces the level of excitement or arousal. While this approach might be beneficial for some learners, it might be detrimental for those in favor of stimulating learning environments.

Somatosensory Mismatch Response in Patients with Cerebral Palsy

Background: Mismatch negativity (MMN), an event-related potential (ERP) component occurring at specific recording sites and latency, is associated with an automatic change detection response, generally elicited using oddball paradigms wherein infrequent stimuli are embedded in repeated, frequent stimuli. To verify the presence of mismatch-related ERP responses to somatosensory stimulation in individuals with cerebral palsy (CP), we conducted a preliminary study involving healthy participants and patients with CP. Methods: Both groups underwent ‘frequent’ and ’infrequent’ stimulation applied to the ring finger and thumb of their left hand, respectively. ERPs were recorded at frontal, central, and parietal scalp locations using electroencephalography. A healthy cohort tested the experimental protocol and showed evidence that mismatch-related ERP responses were observable. Subsequent analysis focused on the patient group. Results: Statistically significant differences between the two types of stimuli were observed on the frontocentral and parietal channels between 150 and 250 ms after the stimulus onset in the patient group. Furthermore, a late discriminative response was observed in the frontal and parietal channels. Conclusion: The results demonstrate the presence of mismatch-related ERP responses in individuals with CP.

Alzheimer’s Disease genetic risk factor APoE 4 impact auditory processing in young adults

AbstractBackgroundRecent studies have suggested that prodromal stages of Alzheimer’s Disease (AD) are accompanied with central auditory system dysfunction, which may be used as early indicators of disease onset and progression. In AD patients of 60 years old and more and in APOE4 carriers, atypical patterns of oscillatory entrainment to repetitive sound transients have been reported and suggested as potential neuromarkers of AD. Whether such alterations of auditory functions relate to genetic risk factor of AD (APOE4) at an early age (<30) is unknown.MethodWe used EEG recordings to measure auditory responses to repetitive sounds (1 second click trains presented at various frequencies (10‐250Hz) in 32 young neurotypical participants). To test whether auditory responsivity is affected by AD risk factor, we compared auditory brain responses from 17 APOE3 (age mean = 21.6, sd = 1.8) and 17 APOE4 carriers (age mean = 23.6, sd = 4.9).ResultComparing the magnitude of auditory event related potentials (ERP) we observed that APOE4 carriers exhibit slightly attenuated P2 and P3 ERP responses as well as delayed N1 and P2 ERP responses compared to APOE3 carriers. Focusing on Auditory Steady State Response (ASSR) power across frequencies (10‐90Hz), we observed that APOE3 carriers exhibit reliably larger neural entrainment than APOE4 carriers (Cohens’ d = 0.8, ‘large’ effect size). This difference was sustained across the peristimulus time course and did vary across stimulus frequencies.ConclusionOverall, these results suggest that central auditory differences can be detected very early in at‐risk populations. Studying these signals could help identify early AD pathology and provide an entry point for therapeutic interventions against neurodegeneration.

Comparison of Event‐Related Potential Markers in Amyloid Positive vs. Amyloid Negative Patients with Mild Cognitive Impairment (MCI) and Dementia in a general neurological clinic

AbstractBackgroundWe used an automated Event Related Potentials (ERP) technique to compare ERP responses in amyloid positive and negative group of 75 patients with Mild Cognitive Impairment (MCI) and Dementia in a general neurological outpatient clinic. Over the years, research labs have repeatedly reported abnormal ERP markers in patients with MCI and dementia. Recent advances in technology have made ERP testing safe, easy to use and low cost, thus rendering it suitable for clinical use. Indeed, ERPs have become more routinely used in clinical assessment of neurological patients with cognitive changes. The possibility that ERP could help identify amyloid status in MCI and dementia patients adds to the potential clinical utility of these biomarkers.MethodPatients with a history of cognitive complains underwent an auditory oddball ERP paradigm in conjunction with routine neurological evaluation and imaging studies. Standard neuropsychological testing were available in most cases. Amyloid PET imaging was done as part of the IDEAS (Imaging Dementia ‐Evidence for Amyloid Scanning) study and provided the readings for amyloid load. ERP responses were analyzed in the context of beta amyloid readings, and in relation to the patients’ degree of cognitive deficits.ResultFinal data analysis will be presented at the time of the conferenceConclusionThe possibility that ERP could help identify amyloid status in MCI and dementia patients adds to the potential clinical utility of these biomarkers. possibility that ERP could help identify amyloid status in MCI and dementia patients adds to the potential clinical utility of these biomarkers.

Comparison of Event‐Related Potential Markers in Amyloid Positive vs. Amyloid Negative Patients with Mild Cognitive Impairment (MCI) and Dementia in a general neurological clinic

AbstractBackgroundWe used an automated Event Related Potentials (ERP) technique to compare ERP responses in amyloid positive and negative group of 75 patients with Mild Cognitive Impairment (MCI) and Dementia in a general neurological outpatient clinic. Over the years, research labs have repeatedly reported abnormal ERP markers in patients with MCI and dementia. Recent advances in technology have made ERP testing safe, easy to use and low cost, thus rendering it suitable for clinical use. Indeed, ERPs have become more routinely used in clinical assessment of neurological patients with cognitive changes. The possibility that ERP could help identify amyloid status in MCI and dementia patients adds to the potential clinical utility of these biomarkers.MethodPatients with a history of cognitive complains underwent an auditory oddball ERP paradigm in conjunction with routine neurological evaluation and imaging studies. Standard neuropsychological testing were available in most cases. Amyloid PET imaging was done as part of the IDEAS (Imaging Dementia ‐Evidence for Amyloid Scanning) study and provided the readings for amyloid load.ERP responses were analyzed in the context of beta amyloid readings, and in relation to the patients’ degree of cognitive deficits.ResultFinal data analysis will be presented at the time of the conferenceConclusionThe possibility that ERP could help identify amyloid status in MCI and dementia patients adds to the potential clinical utility of these biomarkers. possibility that ERP could help identify amyloid status in MCI and dementia patients adds to the potential clinical utility of these biomarkers.

Time-travel to “A review and proposal for a model of sensory predictability in auditory language perception”

Since its inception 60 years ago, the mission of Cortex has been to foster a better understanding of cognition and the relationship between the nervous system, behavior in general, and mental processes in particular. Almost 15 years ago, we submitted “a review and proposal” along these lines to the journal, in which we sought to integrate two components that are not often discussed together, namely the basal ganglia and syntactic language functions (Kotz et al., 2009). One of the main motivations was to find potential explanations for two relatively straightforward earlier empirical observations: (i) electroencephalographic event-related potential responses (EEG/ERPs) known to be sensitive markers of syntactic violations in auditory language processing were found to be absent in persons with focal basal ganglia lesions (Friederici et al., 1999; Frisch et al., 2003; Kotz et al., 2003), and (ii) temporally regular rhythmic tone sequences presented before language stimuli were found to compensate for this effect (Kotz et al., 2005; Kotz & Gunter, 2015; Kotz & Schmidt-Kassow, 2015). The critical question was how to reconcile these specific components, the basal ganglia typically associated with motor behavior and language-related syntactic processes, under one hood to foster a better understanding of how the basal ganglia system contributes to auditory language processing. This core question was the starting point for further own research and trying to solve it, unsurprisingly, led to many more questions and rather few answers. It also changed perspectives and established collaborative efforts, sometimes in unsuspected ways and directions. In light of the journal’s anniversary, we therefore want to take this exciting opportunity for some time travel, looking back at our original conception while linking it to more recent considerations, thereby providing some insights that might be useful for future research.

Decoding speech sounds from neurophysiological data: Practical considerations and theoretical implications.

Machine learning techniques have proven to be a useful tool in cognitive neuroscience. However, their implementation in scalp-recorded electroencephalography (EEG) is relatively limited. To address this, we present three analyses using data from a previous study that examined event-related potential (ERP) responses to a wide range of naturally-produced speech sounds. First, we explore which features of the EEG signal best maximize machine learning accuracy for a voicing distinction, using a support vector machine (SVM). We manipulate three dimensions of the EEG signal as input to the SVM: number of trials averaged, number of time points averaged, and polynomial fit. We discuss the trade-offs in using different feature sets and offer some recommendations for researchers using machine learning. Next, we use SVMs to classify specific pairs of phonemes, finding that we can detect differences in the EEG signal that are not otherwise detectable using conventional ERP analyses. Finally, we characterize the timecourse of phonetic feature decoding across three phonological dimensions (voicing, manner of articulation, and place of articulation), and find that voicing and manner are decodable from neural activity, whereas place of articulation is not. This set of analyses addresses both practical considerations in the application of machine learning to EEG, particularly for speech studies, and also sheds light on current issues regarding the nature of perceptual representations of speech.

Neural correlates of face processing among preschoolers with fragile X syndrome, autism spectrum disorder, autism siblings, and typical development.

The current study examined patterns of event-related potential (ERP) responses during a face processing task in groups of preschoolers uniquely impacted by autism spectrum disorder (ASD), including (1) children with ASD; (2) children with fragile X syndrome (FXS); (3) children with familial risk for ASD, but without a diagnosis (i.e., ASIBs); and (4) a low-risk control (LRC) group. Children with FXS have a high incidence of ASD diagnoses, but there have been no studies of the ERP response to faces in children with FXS and little work focused on children with ASD who have cognitive impairment. The current study examined children's ERP responses to faces and houses in four groups: LRC (N = 28, age = 5.2 years), ASIB (N = 23, age = 5.5 years), FXS (N = 19, age = 5.82 years), and ASD (N = 23, age = 5.5 years). The FXS and ASD groups were characterized by the presence of cognitive impairment. Pictures of upright and inverted faces and houses were presented while recording EEG with a 128-channel system. The N170 occurred at about 200 ms post stimulus onset, was largest on the posterior-lateral electrodes, and was larger for faces than houses. The P1 and N170 ERP components were larger for the FXS group than for the other three groups. The N170 ERP amplitude for the ASD and ASIB groups was smaller than both the LRC and FXS groups, and the LRC and FXS groups had the largest N170 responses on the right side. No difference was found in N170 latency between groups. The similarity of the ASD and ASIB responses suggest a common genetic or environmental origin of the reduced response. Although children with FXS have a high incidence of ASD outcomes, they differed from ASD and ASIB children in this study. Specifically, the children with FXS were hyperresponsive to all stimulus types while the ASD and ASIB groups showed attenuated responses for specific stimuli.