Event-related potentials to auditory and visual selective attention in schizophrenia

Theta and alpha oscillations may underlie improved attention and working memory in musically trained children

INTRODUCTION

Attention and working memory are key cognitive functions that allow us to select and maintain information in our mind for a short time, being essential for our daily life and, in particular, for learning and academic performance. It has been shown that musical training can improve working memory performance, but it is still unclear if and how the neural mechanisms of working memory and particularly attention are implicated in this process. In this work, we aimed to identify the oscillatory signature of bimodal attention and working memory that contributes to improved working memory in musically trained children.

MATERIALS AND METHODS

We recruited children with and without musical training and asked them to complete a bimodal (auditory/visual) attention and working memory task, whereas their brain activity was measured using electroencephalography. Behavioral, time-frequency, and source reconstruction analyses were made.

RESULTS

Results showed that, overall, musically trained children performed better on the task than children without musical training. When comparing musically trained children with children without musical training, we found modulations in the alpha band pre-stimuli onset and the beginning of stimuli onset in the frontal and parietal regions. These correlated with correct responses to the attended modality. Moreover, during the end phase of stimuli presentation, we found modulations correlating with correct responses independent of attention condition in the theta and alpha bands, in the left frontal and right parietal regions.

CONCLUSIONS

These results suggest that musically trained children have improved neuronal mechanisms for both attention allocation and memory encoding. Our results can be important for developing interventions for people with attention and working memory difficulties.

Recovery of auditory evoked response attentional gain modulation following the first psychotic episode indexes improvements in symptom severity

Attentional control of auditory N100/M100 gain is reduced in individuals with first-episode psychosis (FEP). Persistent problems with executive modulation of auditory sensory activity may impact multiple aspects of psychosis. As a follow-up to our prior work reporting deficits in attentional M100 gain modulation in auditory cortex, we examined changes in M100 gain modulation longitudinally, and further examined relationships between auditory M100 and symptoms of psychosis. We compared auditory M100 in auditory sensory cortex between 21 FEP and 29 matched healthy participants and between timepoints separated by 220 ± 100 days. Magnetoencephalography data were recorded while participants alternately attended or ignored tones in an auditory oddball task. M100 was measured as the average of 80-140 ms post-stimulus in source-localized evoked responses within bilateral auditory cortex. Symptoms were assessed using the PANSS and PSYRATS. M100 amplitudes, attentional modulation of M100 amplitudes, and symptom severity all improved in FEP over time. Further, improvement in M100 modulation correlated with improvements in negative symptoms (PANSS) as well as physical, cognitive, and emotional components of hallucinations (PSYRATS). Conversely, improvements in the overall size of the M100, rather than the difference between active and passive M100 amplitudes, were related to worsening of positive symptoms (PANSS) and physical components of hallucinations. Results indicate a link between symptoms (particularly auditory hallucinations) and auditory cortex neurophysiology in FEP, where auditory attention and auditory sensation have opposed relationships to symptom change. These findings may inform current models of psychosis etiology and could provide nonpharmaceutical avenues for early intervention.

Event-related potentials to rare visual targets and negative symptom severity in a transdiagnostic psychiatric sample

OBJECTIVES

Negative psychiatric symptoms are often resistant to treatments, regardless of the disorder in which they appear. One model for a cause of negative symptoms is impairment in higher-order cognition. The current study examined how particular bottom-up and top-down mechanisms of selective attention relate to severity of negative symptoms across a transdiagnostic psychiatric sample.

METHODS

The sample consisted of 130 participants: 25 schizophrenia-spectrum disorders, 26 bipolar disorders, 18 unipolar depression, and 61 nonpsychiatric controls. The relationships between attentional event-related potentials following rare visual targets (i.e., N1, N2b, P2a, and P3b) and severity of the negative symptom domains of anhedonia, avolition, and blunted affect were evaluated using frequentist and Bayesian analyses.

RESULTS

P3b and N2b mean amplitudes were inversely related to the Positive and Negative Syndrome Scale-Negative Symptom Factor severity score across the entire sample. Subsequent regression analyses showed a significant negative transdiagnostic relationship between P3b amplitude and blunted affect severity.

CONCLUSIONS

Results indicate that negative symptoms, and particularly blunted affect, may have a stronger association with deficits in top-down mechanisms of selective attention.

SIGNIFICANCE

This suggests that people with greater severity of blunted affect, independent of diagnosis, do not allocate sufficient cognitive resources when engaging in activities requiring selective attention.

Neural anomalies during vigilance in schizophrenia: Diagnostic specificity and genetic associations

Impaired vigilance is a core cognitive deficit in schizophrenia and may serve as an endophenotype (i.e., mark genetic liability). We used a continuous performance task with perceptually degraded stimuli in schizophrenia patients (N = 48), bipolar disorder patients (N = 26), first-degree biological relatives of schizophrenia patients (N = 55) and bipolar disorder patients (N = 28), as well as healthy controls (N = 68) to clarify whether previously reported vigilance deficits and abnormal neural functions were indicative of genetic liability for schizophrenia as opposed to a generalized liability for severe psychopathology. We also examined variation in the Catechol-O-methyltransferase gene to evaluate whether brain responses were related to genetic variation associated with higher-order cognition. Relatives of schizophrenia patients had an increased rate of misidentification of nontarget stimuli as targets when they were perceptually similar, suggestive of difficulties with contour perception. Larger early visual responses (i.e., N1) were associated with better task performance in patients with schizophrenia consistent with enhanced N1 responses reflecting beneficial neural compensation. Additionally, reduced N2 augmentation to target stimuli was specific to schizophrenia. Both patients with schizophrenia and first-degree relatives displayed reduced late cognitive responses (P3b) that predicted worse performance. First-degree relatives of bipolar patients exhibited performance deficits, and displayed aberrant neural responses that were milder than individuals with liability for schizophrenia and dependent on sex. Variation in the Catechol-O-methyltransferase gene was differentially associated with P3b in schizophrenia and bipolar groups. Poor vigilance in schizophrenia is specifically predicted by a failure to enhance early visual responses, weak augmentation of mid-latency brain responses to targets, and limited engagement of late cognitive responses that may be tied to genetic variation associated with prefrontal dopaminergic availability. Experimental results illustrate specific neural functions that distinguish schizophrenia from bipolar disorder and provides evidence for a putative endophenotype that differentiates genetic liability for schizophrenia from severe mental illness more broadly.

Brain Vital Signs: Expanding From the Auditory to Visual Modality

The critical need for rapid objective, physiological evaluation of brain function at point-of-care has led to the emergence of brain vital signs-a framework encompassing a portable electroencephalography (EEG) and an automated, quick test protocol. This framework enables access to well-established event-related potential (ERP) markers, which are specific to sensory, attention, and cognitive functions in both healthy and patient populations. However, all our applications to-date have used auditory stimulation, which have highlighted application challenges in persons with hearing impairments (e.g., aging, seniors, dementia). Consequently, it has become important to translate brain vital signs into a visual sensory modality. Therefore, the objectives of this study were to: 1) demonstrate the feasibility of visual brain vital signs; and 2) compare and normalize results from visual and auditory brain vital signs. Data were collected from 34 healthy adults (33 ± 13 years) using a 64-channel EEG system. Visual and auditory sequences were kept as comparable as possible to elicit the N100, P300, and N400 responses. Visual brain vital signs were elicited successfully for all three responses across the group (N100: F = 29.8380, p < 0.001; P300: F = 138.8442, p < 0.0001; N400: F = 6.8476, p = 0.01). Initial auditory-visual comparisons across the three components showed attention processing (P300) was found to be the most transferrable across modalities, with no group-level differences and correlated peak amplitudes (rho = 0.7, p = 0.0001) across individuals. Auditory P300 latencies were shorter than visual (p < 0.0001) but normalization and correlation (r = 0.5, p = 0.0033) implied a potential systematic difference across modalities. Reduced auditory N400 amplitudes compared to visual (p = 0.0061) paired with normalization and correlation across individuals (r = 0.6, p = 0.0012), also revealed potential systematic modality differences between reading and listening language comprehension. This study provides an initial understanding of the relationship between the visual and auditory sequences, while importantly establishing a visual sequence within the brain vital signs framework. With both auditory and visual stimulation capabilities available, it is possible to broaden applications across the lifespan.

Neurophysiological Mechanisms of Auditory Information Processing in Adolescence: A Study on Sex Differences

To date, little is known about sex differences in the neurophysiological correlates underlying auditory information processing. In the present study, auditory evoked potentials were evoked in typically developing male (n = 15) and female (n = 14) adolescents (13-18 years) during an auditory oddball task. Girls compared to boys displayed lower N100 and P300 amplitudes to targets. Larger N100 amplitudes in adolescent boys might indicate higher neural sensitivity to changes of incoming auditory information. The P300 findings point toward sex differences in auditory working memory and might suggest that adolescent boys might allocate more attentional resources when processing relevant auditory stimuli than adolescent girls.

Is that me in the mirror? Depersonalisation modulates tactile mirroring mechanisms

Our sense of self is thought to develop through sensory-motor contingencies provided, not only by observing one's own body, but also by mirroring interactions with others. This suggests that there is a strong link between mirroring mechanisms and the bodily self. The present study tested whether this link is expressed at early, implicit stages of the mirroring process or at later, more cognitive stages. We also provide, to the best of our knowledge, the first demonstration of how inter-individual differences in our sense of bodily self may affect mirroring mechanisms. We used somatosensory event-related potentials (SEPs) to investigate the temporal dynamics of mirroring highly self-related information (viewed touch on one's own face) compared to other-related information (viewed touch on a stranger's face), in individuals with low and high levels of depersonalisation, a mental condition characterised by feeling detached or estranged from one's self and body. For the low-depersonalisation group, mirroring for self-related events (P45) preceded mirroring for other-related events (N80). At later stages (P200), mirroring was stronger for other-related than self-related events. This shows that early, implicit and later, more cognitive processes play different relative roles in mirroring self- and other-related bodily events. Critically, mirroring differed in the high-depersonalisation group, specifically for self-related events. An absence of early, implicit mirroring for self-related events over P45 suggests that the associated processes may be the neural correlates of the disembodiment experienced in depersonalisation. A lack of differential mirroring for self- and other-related events over P200 may reflect compensatory mechanisms that redress deficiencies in mirroring at earlier stages, which may break down to give rise to symptoms of depersonalisation. Alternatively, or in addition, they may represent an attenuation of processes related to self-other distinction. Our study thus shows that mirroring, especially for events on one's own face, can be strongly affected by how connected the observer feels to their own bodily self.

Progressive reduction of visual P300 amplitude in patients with first-episode schizophrenia: an ERP study

OBJECTIVE

To understand the underlying dynamic neurophysiological changes over the course of schizophrenia, it is important to study subjects longitudinally from the early stage of the illness. We previously reported that visual P300 was already impaired in patients with first-episode schizophrenia (FESZ). This study demonstrates how the visual P300, as well as earlier components P1, N1, and N200, changed at the 1-year follow-up after their initial measurement.

METHODS

Visual ERPs were recorded with the same experimental paradigm and acquisition protocol at both time points in FESZ (n = 18) and healthy comparison subjects (n = 24). Participants silently counted infrequent target stimuli ("x") amid standard stimuli ("y") presented on the screen while the 64-channel electroencephalogram was recorded.

RESULTS

FESZ showed smaller visual P300, N200, P1 (trend level) amplitude and delayed P300 and N1 latency at both time points; however, only P300 showed progressive amplitude reduction over the course of the illness at 1-year follow-up. P300 latency did not change over time in either group. FESZ showed significantly reduced Spatial Span total score at both time points, and there was a significant negative correlation between P300 peak amplitude and the Brief Psychiatric Rating Scale positive symptom score at baseline.

CONCLUSION

These data show progressive P300 amplitude reduction in response to visual stimuli in the early stage of schizophrenia. These visual P300 findings support the concept of progression of schizophrenia, suggesting the usefulness of the visual P300 as a biological marker of progression.

Comparison of auditory and visual oddball fMRI in schizophrenia

Individuals with schizophrenia often suffer from attentional deficits, both in focusing on task-relevant targets and in inhibiting responses to distractors. Schizophrenia also has a differential impact on attention depending on modality: auditory or visual. However, it remains unclear how abnormal activation of attentional circuitry differs between auditory and visual modalities, as these two modalities have not been directly compared in the same individuals with schizophrenia. We utilized event-related functional magnetic resonance imaging (fMRI) to compare patterns of brain activation during an auditory and visual oddball task in order to identify modality-specific attentional impairment. Healthy controls (n=22) and patients with schizophrenia (n=20) completed auditory and visual oddball tasks in separate sessions. For responses to targets, the auditory modality yielded greater activation than the visual modality (A-V) in auditory cortex, insula, and parietal operculum, but visual activation was greater than auditory (V-A) in visual cortex. For responses to novels, A-V differences were found in auditory cortex, insula, and supramarginal gyrus; and V-A differences in the visual cortex, inferior temporal gyrus, and superior parietal lobule. Group differences in modality-specific activation were found only for novel stimuli; controls showed larger A-V differences than patients in prefrontal cortex and the putamen. Furthermore, for patients, greater severity of negative symptoms was associated with greater divergence of A-V novel activation in the visual cortex. Our results demonstrate that patients have more pronounced activation abnormalities in auditory compared to visual attention, and link modality specific abnormalities to negative symptom severity.

The visual P3a in schizophrenia and bipolar disorder: effects of target and distractor stimuli on the P300

Amplitude reduction of the P300 event-related potential has long been suggested as a marker for schizophrenia. However, recent research has shown that this reduction in the P300 amplitude is not specific to schizophrenia as it can also be observed in related illnesses such as bipolar disorder. Due to this lack of specificity the P300 elicited using traditional oddball paradigms may be a less valuable endophenotypic marker. The current study employed a cognitively demanding three-stimulus oddball paradigm to elicit the P300 to visual target and distracting stimuli. Patients with schizophrenia showed amplitude reductions of P300 components to targets, distractors and frequent stimuli. The P300 in patients with bipolar disorder was not significantly different from either group. The pattern of results may further the understanding of the nature of the impairment in schizophrenia.

Does hallucination affect vigilance performance in schizophrenia? An exploratory study

The present study investigates the role of "auditory verbal hallucination" (AVH) in the attentional processes of individuals diagnosed with schizophrenia compared with healthy participants. The sample consisted of 26 participants diagnosed with schizophrenia divided into - "schizophrenia with hallucination" (N=12) and "schizophrenia without hallucination" (N=14). 13 matched healthy participants were taken. A general health questionnaire was used to screen out psychiatric morbidity in healthy participants. The presence and/or absence of AVH were substantiated through the administration of the Positive and Negative Syndrome Scale (PANSS). Only individuals having higher composite scores in the positive scale were included. Edinburgh Handedness Inventory was administered to all participants. Software designed to measure vigilance was used to assess attentional deficits in the three groups included in the study. The complexity of the "vigilance task" was varied across three parameters: (1) spatial position of the target stimulus and buffer, (2) frequency of the target stimulus and buffer and (3) colour of target stimulus and buffer. The performances of the 3 groups were compared statistically in terms of Hit, Miss and False Alarm scores. Results revealed that schizophrenia patients are deficient as compared to their healthy counterparts in the ability to focus on a specific target while inhibiting non-relevant information across all conditions. Also, schizophrenia patients who have AVH are relatively more deficient as compared to the schizophrenia patients without AVH. It can be concluded that perceptual abnormality in schizophrenia patients with hallucination has an additional negative impact on attentional processes.

The oral trail making test: effects of age and concurrent validity

The oral version of the Trail Making Test (OTMT) is a neuropsychological measure that provides an assessment of sequential set-shifting without the motor and visual demands of the written TMT (WTMT). Originally purposed to serve as an oral analog of the WTMT, the OTMT provides a means to evaluate patients with physical restrictions. However, formal validity studies and available normative data remain sparse. In a sample of healthy adults (n = 81), a strong correlation was observed between OTMT-B and its written counterpart (r = .62), but the correlations were weak between OTMT-A and either written version of the TMT. OTMT-B was significantly correlated with age but not with education or gender, whereas OTMT-A was not significantly correlated with demographic factors. The WTMT to OTMT ratios observed in the current study were generally lower than previously reported and varied across age groups, suggesting that the recommended use of a uniform conversion factor to predict one performance based on the other should be cautiously undertaken. Normative data that have been stratified by age are provided as well as suggestions for using both versions of the TMT in tandem to better elucidate the nature of cognitive deficits and to aid in the localization of cerebral dysfunction.

The course of visual searching to a target in a fixed location: electrophysiological evidence from an emotional flanker task

The present study investigated the course of visual searching to a target in a fixed location, using an emotional flanker task. Event-related potentials (ERPs) were recorded while participants performed the task. Emotional facial expressions were used as emotion-eliciting triggers. The course of visual searching was analyzed through the emotional effects arising from these emotion-eliciting stimuli. The flanker stimuli showed effects at about 150-250 ms following the stimulus onset, while the effect of target stimuli showed effects at about 300-400 ms. The visual search sequence in an emotional flanker task moved from a whole overview to a specific target, even if the target always appeared at a known location. The processing sequence was "parallel" in this task. The results supported the feature integration theory of visual search.

Parallel perceptual enhancement and hierarchic relevance evaluation in an audio-visual conjunction task

Attention directs limited-capacity information processing resources to a subset of available perceptual representations. The mechanisms by which attention selects task-relevant representations for preferential processing are not fully known. Triesman and Gelade's [Triesman, A., Gelade, G., 1980. A feature integration theory of attention. Cognit. Psychol. 12, 97-136.] influential attention model posits that simple features are processed preattentively, in parallel, but that attention is required to serially conjoin multiple features into an object representation. Event-related potentials have provided evidence for this model showing parallel processing of perceptual features in the posterior Selection Negativity (SN) and serial, hierarchic processing of feature conjunctions in the Frontal Selection Positivity (FSP). Most prior studies have been done on conjunctions within one sensory modality while many real-world objects have multimodal features. It is not known if the same neural systems of posterior parallel processing of simple features and frontal serial processing of feature conjunctions seen within a sensory modality also operate on conjunctions between modalities. The current study used ERPs and simultaneously presented auditory and visual stimuli in three task conditions: Attend Auditory (auditory feature determines the target, visual features are irrelevant), Attend Visual (visual features relevant, auditory irrelevant), and Attend Conjunction (target defined by the co-occurrence of an auditory and a visual feature). In the Attend Conjunction condition when the auditory but not the visual feature was a target there was an SN over auditory cortex, when the visual but not auditory stimulus was a target there was an SN over visual cortex, and when both auditory and visual stimuli were targets (i.e. conjunction target) there were SNs over both auditory and visual cortex, indicating parallel processing of the simple features within each modality. In contrast, an FSP was present when either the visual only or both auditory and visual features were targets, but not when only the auditory stimulus was a target, indicating that the conjunction target determination was evaluated serially and hierarchically with visual information taking precedence. This indicates that the detection of a target defined by audio-visual conjunction is achieved via the same mechanism as within a single perceptual modality, through separate, parallel processing of the auditory and visual features and serial processing of the feature conjunction elements, rather than by evaluation of a fused multimodal percept.

An auditory processing abnormality specific to liability for schizophrenia

Abnormal brain activity during the processing of simple sounds is evident in individuals with increased genetic liability for schizophrenia; however, the diagnostic specificity of these abnormalities has yet to be fully examined. Because recent evidence suggests that schizophrenia and bipolar disorder may share aspects of genetic etiology the present study was conducted to determine whether individuals with heightened genetic liability for each disorder manifested distinct neural abnormalities during auditory processing. Utilizing a dichotic listening paradigm, we assessed target tone discrimination and electrophysiological responses in schizophrenia patients, first-degree biological relatives of schizophrenia patients, bipolar disorder patients, first-degree biological relatives of bipolar patients and nonpsychiatric control participants. Schizophrenia patients and relatives of schizophrenia patients demonstrated reductions in an early neural response (i.e. N1) suggestive of deficient sensory registration of auditory stimuli. Bipolar patients and relatives of bipolar patients demonstrated no such abnormality. Both schizophrenia and bipolar patients failed to significantly augment N1 amplitude with attention. Schizophrenia patients also failed to show sensitivity of longer-latency neural processes (N2) to stimulus frequency suggesting a disorder specific deficit in stimulus classification. Only schizophrenia patients exhibited reduced target tone discrimination accuracy. Reduced N1 responses reflective of early auditory processing abnormalities are suggestive of a marker of genetic liability for schizophrenia and may serve as an endophenotype for the disorder.

Positive modulation of cognition and mood in the healthy elderly volunteer following the administration of Centella asiatica

AIMS OF THIS STUDY

Centella asiatica has a reputation to restore decline cognitive function in traditional medicine and in animal model. However, little evidence regarding the efficacy of Centella asiatica from systematized trials is available. Therefore, the present randomized, placebo-controlled, double-blind study investigated the effect of Centella asiatica on cognitive function of healthy elderly volunteer.

MATERIALS AND METHODS

Twenty-eight healthy elderly participants received the plant extract at various doses ranging 250, 500 and 750 mg once daily for 2 months. Cognitive performance was assessed using the computerized test battery and event-related potential whereas mood was assessed using Bond-Lader visual analogue scales prior to the trial and after single, 1 and 2 months after treatment.

RESULTS

The results showed that the high dose of the plant extract enhanced working memory and increased N100 component amplitude of event-related potential. Improvements of self-rated mood were also found following the Centella asiatica treatment.

CONCLUSION

Therefore, the present findings suggest the potential of Centella asiatica to attenuate the age-related decline in cognitive function and mood disorder in the healthy elderly. However, the precise mechanism(s) underlying these effects still require further investigation.

Early visual processing deficits in dysbindin-associated schizophrenia

BACKGROUND

Variation at the dysbindin gene (DTNBP1) has been associated with increased risk for schizophrenia in numerous independent samples and recently with deficits in general and domain-specific cognitive processing. The relationship between dysbindin risk variants and sensory-level deficits in schizophrenia remains to be explored. We investigated P1 performance, a component of early visual processing on which both patients and their relatives show deficits, in carriers and noncarriers of a known dysbindin risk haplotype.

METHODS

Event-related potential responses to simple visual isolated-check stimuli were measured using high-density electrical scalp recordings in 26 individuals meeting DSM-IV criteria for schizophrenia, comprising 14 patients who were carriers of the dysbindin risk haplotype and 12 patients who were nonrisk haplotype carriers.

RESULTS

Carriers of the dysbindin risk haplotype demonstrated significantly reduced P1 amplitudes compared with noncarriers. A large effect size of d = .89 was calculated for the difference in P1 amplitude over scalp sites where the deficit was maximal.

CONCLUSIONS

The P1 deficits associated with a dysbindin risk haplotype previously identified in our sample presents functional confirmation of its deleterious effect on brain activity. Building on evidence of dysbindin's role in higher cognitive function, these early visual processing deficits suggest a generalized role for dysbindin in brain function and is likely to be part of the mechanism by which illness susceptibility is mediated.

Attention and executive function in people with schizophrenia: Relationship with social skills and quality of life

Objective. Executive function and attention are highly complex cognitive constructs that typically reveal evidence of impairment in people with schizophrenia. Studies in this area have traditionally utilised abstract tests of cognitive function and the importance of using more ecologically valid tests has not been extensively recognised. In addition, there has been little previous examination of the relationship between these key cognitive abilities and social functioning and quality of life in this population. Methods. Thirty-six schizophrenic patients and 15 controls were assessed on the Behavioural Assessment of the Dysexecutive Syndrome (BADS) test, three subtests from the Test of Everyday Attention (TEA), a measure of social functioning and a quality of life measure. Results. Analysis of subtest scores revealed that patients were impaired on all attentional measures, but only one BADS subtest score in addition to the BADS profile score. However, 23 patients demonstrated no impairment in their BADS profile scores whilst being impaired on at least one attentional measure. Only the BADS profile score predicted social functioning and quality of life. Conclusions. Ecologically valid tests of attention and executive function can play an important role in defining the cognitive deficits in schizophrenia and how such deficits relate to social function and quality of life.

Disruption of auditory and visual attention in schizophrenia

Disruption of attention is a hallmark symptom of schizophrenia, and event-related potentials have been instrumental in studying this cognitive deficit. Event-related potentials (ERPs) have been used to study attention and its disruption in schizophrenia, with the most common finding of a reduced P300 component in auditory tasks. Some studies have found sparing of the P300 in visual attention, but reduction of an earlier attention-sensitive N2b, suggesting that the N2b may be a more sensitive index of attention disruption in schizophrenia. The current study compared visual and auditory attention using both unimodal and bimodal stimulus presentation in the same participants to examine the impact of schizophrenia on attention at both the early N2b and later P300 stages. Both N2b and P300 showed attention effects, being larger to targets than non-targets in all tasks. The N2b was reduced in the patient group in all tasks except the bimodal attend visual task, while the P300 was not reduced in the patients in any condition. This indicates that early attention, as indexed by the N2b, is differentially impaired in patients with schizophrenia, even when later attention, indexed by the P300, is intact.

Brain Response to Unexpected Novel Noises in Children with Low and High Trait Anxiety

The behavioral inhibition system [Gray, J. A. The neuropsychology of anxiety: An enquiry into the functions of the septo-hippocampal system. Oxford: Oxford University Press, 1982] proposes that anxiety is associated with the processing of novel stimuli. We aimed to explore this relationship by recording auditory event-related potentials associated with unexpected novel noises in typically developing children. Children aged 10–14 years with low (n = 12) and high (n = 11) self-report trait anxiety were assessed using a novelty oddball task. The N1 associated with novel stimuli, specifically the “N1c” component maximal at temporal lobe sites, was of significantly longer latency (p = .014) and greater amplitude (p = .004) in the high compared with the low anxious group. This group difference was supported by linear correlations between N1c amplitude and trait anxiety scores. There was no effect of anxiety on the later novelty P3. These data suggest a subtle moderating role of trait anxiety on brain response to novelty, and further research with clinically anxious children is indicated.