不同范围提示下儿童视觉空间注意的ERP研究

目的:研究儿童在不同范围提示下视觉空间注意的事件相关电位(ERP)特征.方法:采用“提示-目标”的视觉实验范式,以圆圈提示不同等级的搜索范围,对14名儿童进行检测.通过ERP技术分析儿童不同空间注意等级的早成分.结果:随提示范围的减小,反应时加快,后部P1和N1波幅增大,前部P2波幅减小.结论:在空间注意加工的早期阶段,儿童依赖提示等级的有效性调动脑资源;而晚期阶段需要额外的脑资源.     

利他林对注意缺陷多动障碍患儿注意能力影响的ERP研究

目的:探讨注意缺陷多动障碍(ADHD)患儿的视觉空间注意刺激诱发的事件相关电位(ERP)特征,并研究利他林(MPH)对其影响。方法:采用有效提示、无效提示刺激模块对22名ADHD患儿和22名年龄匹配的正常儿童进行ERP检测和记录其行为学表现。ADHD患儿在服MPH前和服MPH后2 h分别接受两次ERP检测。结果:与正常对照组相比,ADHD组在服MPH前,额部N2波潜伏期显著延长(P<0．05),各导联P2、N2波波幅显著降低(P<0．05);服MPH后2 h额部N2波潜伏期显著缩短(P<0．05),各导联波幅显著增高(P<0．05);服MPH后2 h各导联P2、N2波的潜伏期及波幅与正常对照组比较差异无显著意义(P>0．05)。结论:视觉空间注意ERP可以客观检测ADHD患儿注意缺陷的存在及程度,为临床诊断和评价MPH疗效提供了客观依据。     

正常青年人视觉、听觉诱发的ERP的比较

35例正常青年人同时进行视觉、听觉不同刺激模式检测的事件相关电位(ERP)进行比较分析,我们发现不同刺激模式诱发出的ERP各波的潜伏期,波幅均不相同,尤其是不同模式的靶与非靶刺激诱发的P_2波的波幅有明显的差距(P<0.05)。本文对其原因和不同年龄的P_3波在颅顶有不同的分布部位以及其中一些人P_3波电位值两半球不对称性的机理进行了初步探讨。     

正常青年人视觉、听觉诱发的ERP的比较

对３５例正常青年人同时进行视觉、听觉不同刺激模式检测到的事件相关电位（ＥＲＰ）进行比较分析，发现不同刺激模式诱发出的ＥＲＰ各波的潜伏期、波幅均不相同。本文对其原因和不同年龄的Ｐ３波在颅顶有不同的分布部位以及其中一些Ｐ３波电位值两半球不对称性的机理进行了初步探讨。     

听力障碍与听力正常儿童视觉注意技能比较

目的:考察听力障碍和听力正常儿童的视觉注意技能。方法:采用Toni智力测验筛选出16名听力障碍儿童和18名听力正常儿童为被试,采用DMDX系统呈现实验材料和记录被试完成视觉搜索任务的反应时和准确率。结果:听力障碍儿童的平均反应时长于听力正常儿童(1272.4±60.3/977.6±51.3,P=0.001);搜索项目大小与被试听力的交互作用及被试听力、搜索项目大小和搜索特征的交互作用均显著(F(2,29)=5.863,P=0.005;F(4,29)=3.14,P=0.017)。结论:听力障碍儿童搜索目标的速度慢于听力正常儿童;两组被试有相似的加工方式,即对单一的颜色特征的搜索进行了平行加工,而对方向和颜色的混合特征进行了系列加工。     

正常儿童汉字语义事件相关电位的研究

目的：探讨单个汉字语义刺激正常儿童的事件相关电位，对三种不同类别（有关联、无关联、假字）ERP的特征进行比较研究。方法：对31名10岁的儿童采用加拿大Stellate systems32道数字化无纸脑电图仪，并用单个汉字语义刺激模块进行检测。刺激信号同步触发，脑电图（EEG）同步记录，从EEG中提取三种不同类别刺激的ERP，对P2和N2进行分析。结果：单个汉字语义有戈联的P2及N2潜伏期与无关联，假字组相比有显著性差异（P〈0．01）；波幅无显著性差异（P〉0．05）；N2波广泛分布头皮各区，左右大脑半球无明显差异（P〉0．05）。结论：三种不同类别的ERP波形及潜伏期各不相同；N2是语义刺激ERP的主成分，P2可认为与儿童语义的早期理解有关。     

幼儿视觉ERP：I．P_3波幅的研究

本研究的目的是了解幼儿在人像再认过程中Ｐ３波幅变化规律，为幼儿认知发育提供神经电生理的依据。结果证明幼儿无任务Ｐ３波幅比任务ｐ３波幅低，Ｐ３的引出与低概率刺激有关。再认熟悉人Ｐ３波幅大于再认陌生人，推论再认熟悉人的场合修正量大于再认陌生人。幼儿Ｐ３波幅的部位效应表现为从Ｏｚ至Ｆｚ渐次降低。Ｐ３波幅变化还与幼儿记忆、注意等心理过程有关。     

基于三维层析技术的选择性注意脑电研究

利用脑电三维层析技术对左右视野空间选择性注意的ERP进行了研究。结果表明,层析得到的电源强度与头表的脑电数据相比,能更好地反映注意导致的P1、N1相对增强效应,其中尤以N1的增强比较明显。此外,层析结果中还能观察到在该头表数据中未能反映出来的C1成分。     

注意缺陷多动障碍儿童在不同情绪面孔刺激下的持续注意任务事件相关电位

目的:了解不同情绪面孔刺激下注意缺陷多动障碍(ADHD)患儿执行持续注意任务时的事件相关电位特征。方法:选取符合美国精神障碍诊断与统计手册第4版(DSM-IV)诊断标准的混合型ADHD患儿32例(年龄9~15岁)及年龄、性别匹配的正常对照组儿童32例,要求被试在高兴、中性、恐惧和愤怒等4种情绪面孔刺激随机呈现后执行注意与选择任务,同时记录事件相关电位。观察ADHD患者和正常对照组儿童面孔诱发的N170电位及靶刺激诱发的P300电位的特征。结果:ADHD组患儿在4种不同情绪面孔刺激下颞枕区面孔特异性N170波波幅均低于对照组[如恐惧面孔,(17.7±9.5)μv vs.(25.8±14.0)μv,P0.05],顶枕区P300潜伏期长于对照组[如恐惧面孔,[(454.2±51.3)ms vs.(433.0±29.8)ms,P0.05]。ADHD患儿组在四情绪面孔诱发的N170波幅和潜伏期差异无统计学意义(P0.05),诱发的P300在四种情绪刺激中以恐惧面孔刺激后执行注意任务的P300波幅最低,潜伏期最长。结论:ADHD儿童在4种不同情绪面孔刺激下,以恐惧面孔刺激引起的P300波幅最低,且P300潜伏期延长最明显。提示恐惧面孔可能影响ADHD患儿情绪调节,并影响其持续注意过程。     

正常儿童ERP与智力关系的研究

３０例正常儿童进行了事件相关电位（ＥＲＰ）与智商（ＩＱ）和学习成绩的对照检查，发现Ｐ３００波群中Ｐ３的潜伏期（ＰＬ）与ＩＱ的高低和学习成绩有显著相关性（但３例例外），提示Ｐ３的ＰＬ可作为评价并指导开发儿童智力的参考指标之一，而Ｎ４００无明确价值。     

Effects of Foveal Task Load on Visual-Spatial Attention: Event-Related Brain Potentials and Performance

The effects of foveal task difficulty on the processing of events in the visual periphery were investigated through an analysis of event-related brain potentials and performance measures. Subjects performed a foveally presented continuous monitoring task both separately and together with an arrow discrimination task that was presented at three different retinal eccentricities. The subjects detected occasional failures in the monitoring task while also responding to designated targets in the left and right visual fields. The analysis of the event-related brain potentials elicited by discrete events in the arrow discrimination task indicated that the amplitude of the N190 and P300 components decreased with both the introduction of the foveal task and an increase in its difficulty. The N160 component was sensitive to the distribution of attention within a task but was uninfluenced by dual task demands. These findings suggest that the N160 reflects the distribution of attention to different spatial locations within a task while the N190 may index the distribution of general purpose perceptual resources. P300 appears to index the allocation of perceptual/central processing resources. The implications of the results for models of resource allocation and attentional gradients are discussed.     

Adult attachment and emotional processing biases: An Event-Related Potentials (ERPs) study

Attachment-related electrophysiological differences in emotional processing biases were examined using Event-Related Potentials (ERPs). We identified ERP correlates of emotional processing by comparing ERPs elicited in trials with angry and neutral faces. These emotional expression effects were then compared across groups with secure, anxious and avoidant attachment orientations. Results revealed significant interactions between attachment orientation and facial expression in mean amplitudes of the early C1 (50-80ms post-stimulus) and P1 (80-120ms post-stimulus) ERP components. Significant differences in C1 and P1 mean amplitudes were found at occipital and posterior-parietal channels in response to angry compared with neutral faces only within the avoidant attachment group. No such differences were found within the secure or anxious attachment groups. The present study underscores the usefulness of the ERP methodology, as a sensitive measure for the study of emotional processing biases in the research field of attachment.     

慢性精神分裂症事件相关电位P300与认知功能成套测验的研究

目的探讨慢性精神分裂症P300的波幅、潜伏期的变化,及其与认知功能成套测验的关系。方法检测41例慢性精神分裂症患者（患者组）及40名正常人（对照组）Cz、Fz、Pz 3点的P300,并用认知功能成套测验（MCCB）评定其认知功能。结果与正常对照相比,在Cz、Fz、Pz 3点,患者组P300波幅降低,潜伏期延长 患者组女性波幅明显比男性高。P300与MCCB相关分析显示,Fz潜伏期与连线、符号编码及持续操作呈负相关 Cz潜伏期与连线、符号编码、言语记忆及迷宫呈负相关 Pz潜伏期与符号编码、迷宫及视觉记忆呈负相关 Pz波幅与符号编码、空间广度、迷宫及视觉记忆呈正相关。结论P300及MCCB可以反映出额叶、顶叶及枕叶的情况,将神经生理学与神经心理学结合起来,说明他们可以从两方面共同对大脑认知功能做出评定。     

Within-Channel Selection and Event-Related Potentials During Selective Auditory Attention

Event-related potentials were recorded from subjects who listened selectively to stimuli in one of two input channels (ears). The stimuli were random sequences of five vowels and a tone pip. In separate experimental runs, the difficulty of within-channel selection was manipulated by designating either tone (T), one vowel (1V), or two vowels (2V) as targets. An attention-related negativity (Nd) was observed for attended nontarget vowels irrespective of the target difficulty, but the early, centrally maximal phase of Nd was substantial only for the one-vowel and two-vowel conditions. The Nd between its early and late peaks was significantly larger for the two-vowel condition than for the one-vowel and tone conditions. The 2V minus 1V difference in Nd had a closely similar distribution to the early Nd. These target difficulty effects were interpreted as suggesting that the early Nd recorded in two-selection tasks can be related to a within-channel selection process as well as a between-channel selection process. The more anteriorly distributed, later phase of Nd was suggested to be rather insensitive to the difficulty of the within-channel selection. The nature of the within-channel selection underlying the early Nd was discussed in relation to controlled memory search operations.     

Effects of Stimulation Rate and Attribute Cuing on Event-Related Potentials During Selective Auditory Attention

Auditory event-related potentials (ERPs) were recorded from subjects who attended selectively to a sequence of tones of one frequency and ignored a comparable sequence of tones having a different frequency and spatial origin. In one condition the tones consisted of randomized sequences of brief tone pips while in a second condition the tones were brief increments in intensity (pedestals) of continuous tones at the two frequencies. The tone pips and pedestals were delivered at comparable interstimulus intervals (ISIs), which were short (250–550 ms) in some runs and long (1250–2750 ms) in others. For both classes of stimuli, the subject's task was to detect occasional “target” tones of a slightly shorter duration than the more frequent “standard” tones. Stimuli of the attended frequency elicited a broad negative ERP component (Nd) relative to the unattended tone ERPs. The Nd wave had a considerably shorter onset latency and was smaller in overall amplitude at the faster rate of stimulation. However, the Nd wave did not differ in latency or amplitude between the tone pip and pedestal conditions at corresponding ISIs, suggesting that a high rate of information delivery is a more important factor in accelerating Nd onset than is the continuous reinforcement of the sensory cues that define the two classes of input.     

Stability of Late Event-Related Potentials: Topographical Descriptors of Motor Control Compared with the P300 Amplitude

The P300-amplitude evoked with an acoustic oddball-paradigm is considered the most stable late event-related potential (ERP). This amplitude-index has become a standard parameter in electrophysiology. Recently, a robust ERP-parameter (NoGo-anteriorization, NGA) has been introduced, which reflects spatial brain electrical changes in relation to execution and inhibition of a motor response elicited with a Continuous Performance Test (CPT). The current study refers to the stability of this new topographical ERP-parameter compared to the stability of the classical P300-amplitude. For that purpose, 12 healthy subjects were investigated with both paradigms during recording of a 21-channel EEG. Analysis of the resulting ERPs revealed a very high stability for both, topographical and amplitude index: In every single subject, the brain electrical fields were characterized by a more anterior location in the NoGo- compared to the Go-condition (=NGA) and by higher amplitudes after target compared to distractor condition. T-tests, analyses of the effect size and of the power revealed equivalent differences between the two contrasting conditions for the topographical compared to the amplitude index. These results indicate that the stability of the topographical ERP-parameters elicited with the CPT is sufficient for an electrophysiological standard-index. The possibility to elicit a robust and specific spatial brain activation with the CPT is an ideal completion to the classical P300 amplitude effect and, therefore, hopefully will be a useful expansion of the standard paradigms in electrophysiological laboratories.     

Combined Use of Microreflexes and Event-Related Brain Potentials as Measures of Auditory Selective Attention

Two versions of a selective listening experiment were conducted in an attempt to specify the level of the nervous system at which selective attention first influences auditory information processing. Post-auricular reflexes (PARs), preputse inhibition of reflexes, and the N1 component of the event-related potential (ERP) were measured concurrently to assess auditory processing in the hindbrain. midbrain. and forebrain. respectively. Sequences of intense, reflex-eliciting tones were presented to the two ears in random order and at a rapid rate as subjects listened to a designated ear to detect rare tones of slightly lower intensity. The ERPs showed the typical enhancement of early and late negativity (Nd) to attended car tunes, with the early Nd overlapping the evoked N1 component. Although there was an overall effect of attention direction on the efferent limb of the post-auricular reflex, no effect of selective attention on the afferent limb was observed. A selective sensory attentional effect was found for prepulse inhibition of the post-auricular reflex: Inhibition of PAR amplitude was enhanced when the immediately preceding tone was in the attended ear relative to when it was in the unattended ear. These results, together with findings from prior studies of reflexes and ERPs. indicate that evoked auditorv activity in the lower brainstem is obligatory and invariant with attention, whereas later activity mediated in the upper brainstem can be modulated by attention.     

Attention to Color: An Analysis of Selection, Controlled Search, and Motor Activation, Using Event-Related Potentials

In this study the organization of information processing in a selective search task was examined by analyzing event-related potentials. This task consisted of searching for target letters in a relevant (attended) color. The ERPs revealed two different effects of attention: an early occipital negativity (+/- 150 ms) reflecting feature-specific attention, and a later, central N2b component (+/- 240 ms) reflecting covert orienting of attention. A later, prolonged negativity (search-related negativity) (+/- 300 ms), maximal at Cz, was related to controlled search to letters in the attended color. Detection of relevant targets resulted in a parietal P3b component. Depending on stimulus presentation conditions an earlier response to both attended and unattended targets was found: an N2 component (+/- 250 ms). In these same conditions, C'3-C'4 asymmetries (Corrected Motor Asymmetries--CMA) suggested motor activation at +/- 300 ms, in the same time range as search-related negativity. It was argued that N2 and CMA suggest the existence of a preattentive target detection system, operating in parallel with a slower serial attentive system, as reflected by N2b and search negativity.     

Event-Related Potentials, Spatial Orienting, and Reading Disabilities

Event-related potentials (ERPs) were used to investigate the effects of visual-spatial orienting on selective neural processing in boys with learning disabilities. Twenty-seven 8-12 year old boys were classified into four groups depending on whether or not they had a reading disability or attention deficit disorder. Event-related potentials were recorded over the left and right occipital, central, and frontal cortical regions. The behavioral task required the subjects 1) to rapidly switch their attention from the center to the periphery of the visual field (spatial component), and 2) to selectively respond to a target versus a nontarget flash when the target was presented in the relevant visual field (nonspatial component). The amplitude of two ERP components was enhanced in response to relevant as compared to irrelevant stimuli. The enhancement of an early negative occipital-central component, which peaked 180-200 ms following targets (N1), indicated that selective neural processing associated with spatial attention could be switched in 600 ms. This enhancement of N1 was greater in boys with than without a reading disability, which implies that reading disability is associated with enhanced spatial attention. The enhancement of a later positive component, which peaked 300-340 ms following targets (P3), suggested that nonspatial target selection was reduced in boys with a reading disability, particularly over the left occipital hemisphere. Target relevance and reading disability also influenced trial-to-trial variability in the ERP waveform. The effects of reading disability on event-related potentials did not vary as a function of attention deficit disorder, indicating that these two disorders are distinct.