J.E.A. Stauder

Developmental differences in behavioral and event-related brain responses associated with response preparation and inhibition in a go/nogo task

The present study investigated developmental trends in response inhibition and preparation by studying behavior and event-related brain activity in a cued go/nogo task, administered to nine-year-old children and young adults. Hits, false alarms, inattention, and impulsivity scores and ERP measures of inhibition (fronto-central nogo-N2 and P3), target selection (parietal go-nogo P3 difference), and response preparation (contingent negative variation; CNV) were collected. Higher false alarm and impulsivity scores and the absence of the fronto-central nogo P3 all suggest a developmental lag in response inhibition in children. A developmental lag in sustained attention processes was suggested by worse target detection and larger parietal target/nontarget P3 effects in children. Cue orientation and response preparation processes were respectively measured by early and late CNV activity. Children displayed smaller early CNV amplitudes at fronto-central locations, but mature late CNV. The smaller early CNV activity might indicate inefficient cue-orientation processes caused by incomplete frontal lobe development.

Perceptual Processing among High-functioning Persons with Autism

Two tasks were used to assess the processing of whole versus parts of objects in a group of high-functioning children and adolescents with autism (N = 11) and a comparison group of typically developing peers (N = 11) matched for chronological age and IQ. In the first task, only the children with autism showed a global advantage, and the two groups showed similar interference between levels. In the second task, the children with autism, despite longer RTs, showed similar performance to the comparison group with regard to the effect of goodness on visual parsing. Contrary to expectations based on the central coherence and hierarchisation deficit theories, these findings indicate intact holistic processing among persons with autism. The implications of these findings are discussed in relation to apparently discrepant evidence from other studies.

The development of visual- and auditory processing in Rett syndrome: An ERP study

Rett syndrome is a neurodevelopmental disorder that occurs almost exclusively in females. It is characterized by a progressive loss of intellectual functioning and motor skills, and the development of stereotypic hand movements, that occur after a period of normal development. Event-related potentials were recorded to a passive auditory- and visual oddball task in 17 females with Rett syndrome aged between 2 and 60 years, and age-matched controls. Overall the participants with Rett syndrome had longer ERP latencies and smaller ERP amplitudes than the Control group suggesting slowed information processing and reduced brain activation. The Rett groups also failed to show typical developmental changes in event-related brain activity and revealed a marked decline in ERP task modulation with increasing age.

Development and gender in the P50 paradigm

OBJECTIVE The relative change in amplitude of the P50 component in response to the second click compared to the first one is commonly thought to index sensory gating. Despite numerous P50 gating studies, reports about its development are scarce. The present study examined the development and gender differences of P50 sensory gating. METHODS A standard P50 paradigm was used to study sensory gating in adults (N=31) and in children aged 10-12 years (N=29), 8-9 years (N=26) and 5-7 years (N=26). RESULTS The speed of processing and the frontocentral scalp distribution in P50 sensory gating are already mature at the age of 5 years. However, children of 5-7 years of age had smaller amplitudes to the first response and showed less sensory gating compared to the older age groups. No gender differences were found. CONCLUSIONS Sensory gating matures around the age of 8 years. SIGNIFICANCE The current data help in evaluating whether abnormal P50 sensory gating is due to maturational delay. There is no need to take into account gender differences.

Multi-modal P3 deflation of event-related brain activity in Prader-Willi syndrome

Adults with Prader-Willi syndrome (PWS) and normal controls participated in a cognitive psychophysiology study in which event-related brain activity was recorded in a visual and auditory oddball task. In both tasks, participants were instructed to press a hand key to a target stimulus. All participants had successful task performance but persons with PWS had more target omissions than controls in the visual oddball task. The event-related brain activity in the PWS group revealed an abnormal deflation of the P3 component in both the visual and auditory oddball tasks. The findings support the notion that the auditory modality is more affected than the visual modality and of a short-term memory impairment in persons with PWS.

Differences in behavioural phenotype between parental deletion and maternal uniparental disomy in Prader-Willi syndrome: an ERP study

OBJECTIVE Paternal deletion and maternal uniparental disomy are the principal genetic subtypes associated with Prader-Willi syndrome (PWS). Recent clinical findings suggest differences in phenotype between these subtypes. The present experimental study addresses this issue using a cognitive psycho-physiological setup. METHODS Behaviour and event-related brain activity (ERP) was recorded by a continuous performance response inhibition task (CPT-AX) in adults with paternal deletion PWS (n=11), maternal uniparental disomy PWS (n=11) and normal controls (n=11). The dependent behavioural variables of the CPT-AX task were reaction time and correct scores. For the ERPs the N200 and P300 components were included which are related to early modality-specific inhibition and late general inhibition, respectively. RESULTS The disomy group had fewer correct scores and increased reaction times as compared to the CPT-AX task than the control and deletion group. Both PWS subgroups differed significantly from the control group for the N200 amplitude. Only the control group showed the typical task modulation for the N200 amplitude. The amplitude of the P300 component was considerably smaller in the uniparental disomy group than in the deletion and control groups. CONCLUSIONS The ERP results suggest that early modality specific inhibition is impaired in both PWS genetic subtypes. Late general inhibition is impaired in the uniparental disomy group only. Thus, although the ERP data suggests a common impairment in early visual inhibition processing, uniparental disomy and parental deletion genetic PWS subtypes clearly differ in their behavioural and brain activation phenotypes. SIGNIFICANCE The present study is the first experimental demonstration which explains the two principal genetic mechanisms that hinder the expression of the genes at 15q11-q13g in PWS result in different behavioural phenotype.

Auditory attention processing in 5-year-old children born preterm: evidence from event-related potentials.

The assumption that children born preterm have difficulties in maintaining active attention was tested in passive and active tasks. Twenty 5‐year‐old children born preterm at 26 to 32 weeks gestational age were compared with 20 children born at term, matched for age and IQ, using an auditory paradigm. In the passive task participants had to watch a videotape of a cartoon and ignore auditory stimuli. In the active task they had to detect a rare tone (the ‘target’ tone; 10% of the tones presented) among frequent tones (the ‘standard’ tone; 90%). Accuracy and reaction time were analysed, and event‐related potentials (ERPs) were recorded at the scalp sites Fz, Cz, T3, T4, Pz, Oz, and two electrodes for the left mastoid (passive task); and Fz, F7, F8, Cz, T3, T4, Pz, and Oz (for the active task). Behavioural and electrophysiological data were analysed with repeated‐measure ANOVAs. The results showed a significant group effect only on the active task. The preterm group scored fewer correct hits (correct detection of target tone) and were less efficient in their attentional strategy as assessed by ERP components.

Extreme prematurity in healthy 5-year-old children: A re-analysis of sex effects on event-related brain activity

A male disadvantage has been reported in several outcome studies of children born preterm. Twenty-two healthy premature children (10 girls, 12 boys) born between 25 and 28 weeks of gestation and 20 controls born full-term (10 boys, 10 girls) were matched on socioeconomical status and age. Event-related potentials (ERPs) were recorded by using 14 electrodes in a visual oddball task, with 75% frequent and 25% rare stimuli. This task elicited a larger P3 to the rare than to the frequent stimuli, with a prominent parietocentral localization. However, the amplitude was larger in full-term boys than in full-term girls, a difference that was not observed between preterm boys and preterm girls, especially to targets and on the central electrodes. In addition, the preterm group was characterized by a frontal slow wave larger in boys than in girls. In these prematures, the lack of the sex-related difference may be accounted by differences in the strength of the neuronal generators in males, as they might have been affected by the high level of androgens by the fetal testis under the control of placental gonadotropes during the first two thirds of gestation.

The development of passive auditory novelty processing.

In a passive auditory oddball study the development of novelty processing was examined in 5-7 (N=26), 8-9 (N=31), 10-12 (N=30), and 18-29 (N=35) years olds. Even though the main goal of this study was to replicate the findings of an earlier one, a shorter and simplified paradigm was used in order to gather developmental reference data for non-responsive patient groups that are unable to give an overt response. As expected, this adapted procedure replicated the findings regarding the development of passive novel sound processing. Firstly, the present data indicated two novelty components, each with a different topography and a different development. Secondly, both novelty components were still not mature in 10-12 years olds. The early novelty P3 had a central focus and its amplitude became more positive with increasing age. Also, its latency did not differ between the four age groups. The focus of the late novelty P3 shifted from frontocentral in 5-7 years olds to parietal in adults. In addition, the late novelty P3 amplitude at Pz became more positive with age, while the late novelty P3 latency was longer in 5-7 and 8-9 years olds compared to 10-12 years olds and adults. Thus, it appears that the adapted paradigm is a suitable tool for assessing auditory novelty processing in non-responsive patients.

Age, intelligence, and event-related brain potentials during late childhood: A longitudinal study

The relation between event-related brain activity, age, and intelligence was studied using a visual oddball task presented longitudinally to girls at 9, 10, and 11 years of age. The event-related brain potential (ERP) components showed typical gradual decrements in latency and amplitude with increasing age, but there were also nonlinear changes in event-related brain activity with age. Regression analyses between Ravens intelligence scores and latency of the ERP components showed negative correlations for the late endogenous components at age 9. At ages 10 and 11, the earlier components showed positive correlations while the later components continued to show negative correlations. The amplitude measures showed only positive correlations and these correlations shifted from the exogenous P1 component at age 9 towards the later endogenous components at ages 10 and 11. The present findings suggest a qualitative shift in the relation between event-related brain activity and intelligence between 9 and 10 years of age.