Visual Event-related Potential Study Research Articles

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.

A visual ERP study of impulse inhibition following a zaleplon-induced nap after sleep deprivation.

The side effects of a zaleplon-induced nap as a countermeasure in the reduction of impulse inhibition function decline following 30 h of sleep deprivation (SD) were examined by event-related brain potentials. Sixteen adult participants performed a Go/NoGo task at five time points: (1) baseline; (2) after 30 h of SD; (3) upon sudden awakening, also called 2 h post-drug; (4) 4 h post-drug; and (5) 6 h post-drug. Behavior results show an increase in both reaction time and false alarm rates after SD and sudden awakening, and a marked decrease at 4 h and 6 h post-drug in zaleplon and placebo conditions. However, no difference was observed between the zaleplon condition and the placebo condition. In event-related potential (ERP) reults compared with results obtained under control conditions, NoGo-P3 latencies significantly increased, whereas the Nogo-P3 amplitude decreased after 30 h of SD and sudden awakening in both the zaleplon condition and the placebo condition. These results indicate that SD attenuates resource allocation and error monitoring for NoGo stimuli. In addition, NoGo-P3 latencies were longer in the zaleplon condition compared with the placebo condition at sudden awakening. Additionally, the NoGo-P3 latencies were shorter in the zaleplon condition than in the placebo condition at 4 h and 6 h post-drug. These results indicate that zaleplon at a dose of 10 mg/day may help subjects achieve a better recovery or maintain better impulse inhibition function, although the side effects of zaleplon last at least 2 h post-drug.

Impact of meditation on emotional processing—A visual ERP study

Impact of meditation on emotional processing, and its clinical applications, has recently drawn significant interest. In this visual event-related potential (ERP) study we investigated whether long-term meditation practitioners exhibit different ERP responses to the emotional load of stimuli (IAPS pictures) than control subjects with no experience in meditation. Differences were observed in the late positive potential (LPP). LPP amplitude is typically greater in ERPs evoked by emotionally arousing scenes, specifically negative images, compared to neutral scenes. This effect was also replicated in our study, but not in case of meditators’ frontal scalp regions, who differed significantly in this respect from control subjects. Our findings provide support for different emotional processing in meditation practitioners: at high levels of processing meditators are less affected by stimuli with adverse emotional load, while processing of positive stimuli remains unaltered. To further confirm this observation, a long-term longitudinal random assignment study would be desirable.

Chinese children developmental dyslexia:a visual event related potential study

目的 考察阅读障碍儿童的视觉巨细胞系统功能的神经心理学特性,探讨阅读障碍儿童与正常儿童的左右枕叶对单侧投射的视觉刺激的敏感性及其功能的半球差异特性.方法 用单侧视野投射方法,使用具有高时间频率的黑白对比视觉信号,同时使用ERP分析系统记录被试在完成简单视觉任务时的波形.结果 ①正常儿童在完成左右单侧视野投射任务的反应时基本相同[(294.7±12.47)ms～(298.3±135.8)ms],左侧枕叶加工来自右侧视野的视觉信号产生的ERP波形与右侧枕叶加工对侧视野信息产生的波形基本一致;②阅读障碍儿童的脑电波形与正常儿童比较差异有显著性;这种差异尤其表现在左侧枕叶O1的P120的峰潜伏期显著延迟为136.57 ms.结论 正常儿童的视觉巨细胞系统左右半球的功能是均势的,没有偏侧化的倾向;而阅读障碍儿童的视觉功能发育可能落后于正常儿童,并且在枕叶皮质存在左右半球差异,尤其是左侧枕叶的功能差异,这可能是阅读障碍儿童视觉巨细胞系统功能的发育的主要神经心理学特性。

Cognitive resource model for the information-processing of task-irrelevant visual stimuli.

In order to elucidate possible factors that effect P3s to task-irrelevant visual stimuli (non-target P3s), we made a normative visual event-related potential study with button-press tasks in four different conditions in which two factors (the number of colors of non-target stimuli, and the shape of the stimuli) were manipulated without any change in task nor target/non-target ratio. The peak distributions of non-target P3s (centrally peaking) were significantly different from those of task-relevant P3s (parietally peaking) in all conditions. The amplitude of non-target P3 decreased as the variety of colors of the non-target stimuli increased. The amplitude of non-target P3 to colored solid circles was larger than that of non-target P3 to colored Stroop stimuli. Between each condition, task- relevant P3 and reaction time showed no significant difference. Both the variety of non-target stimuli and the shape of the stimuli were shown to have effects on the amplitudes of non-target P3s without any alteration in task-relevant P3s. It is suggested that the amplitude behaviors of non-target P3s partly reflect the amount of cognitive resource allocated for each different kind of task-irrelevant visual stimuli.

To fixate or not to fixate. The problem of undetected strabismic subjects in visual evoked potential research.

A common strategy in neuropsychological research involves the presentation of stimuli in left and in right visual fields in order to study possible processing differences by the right and left hemispheres of the brain. Examples of strictly behavioral studies are those of Dimond and Beaumont (1973). in which vigilance performance of the two hemispheres was compared, and of Pennal (1977), in which hemispheric asymmetries in color processing were examined. Visual event-related potential (ERP) researchers have used a similar strategy to investigate effects of visual field location on ERP recorded from over both hemispheres (e.g., Andreassi et al., 1975, and Ledlow et al., 1978). In the study by Andreassi et al., the results showed that stimuli presented in the left visual field (LVF) resulted in shorter visual ERP latencies in the right occipital area than in the left, while in the case of stimuli presented in the right visual field (RVF), the opposite occurred. This field effect on visual ERP latencies has also been reported by Ledlow et al. (1978) and by Andreassi et al. (1980). Whether a study is strictly a behavioral one or involves the measurement of ERPs, it is critical that the subject fixate a t the center of the visual field if the two hemispheres are to receive differential stimulation. We became concerned about the ability of subjects to fixate when, in one study (Andreassi et al., 1980), two of 12 subjects did not show the expected contralateral hemisphere latency advantage for eccentric stimuli. This occurred even though eye movement (vertical and horizontal) was monitored by electro-oculography and was stored on tape for later analysis. In our laboratory, we now screen' all potential subjects for visual acuity, strabism w b and depth acuity before their participation in visual ERP studies. Persons with eye muscle imbalance are not always detectable by casual observation and they may readily pass a binocular visual acuity test since they tend to use one eye in viewing. It was reasoned that individuals with strabismus would have difficulty maintaining their line of sight on some central fixation point. Therefore, even though electrooculography (EOG) is measured, these individuals may take up some different fixation point. Also, deviations from center would not be detected and the usual contralateral effect might not be observed. We believe that the absence of the contralateral hemisphere effect indicates that one or the other hemisphere is not being differentially stimulated. The depth acuity test was initiated as an additional check, since individuals with