事件相关电位N270对脑梗死患者认知功能的评价

目的通过对脑梗死后无临床症状认知障碍患者和年龄匹配的健康对照者视觉P300和N270的潜伏期和波幅进行检查,以调查N270作为临床检查方法来评估脑卒中后患者认知状态的可行性。方法具有相同形状(匹配条件)或不同形状(冲突条件)的刺激对随机出现给受试者。每对由两个连续的刺激(S1和S2)组成,历时300ms;它们之间出现的间隔时间是700ms。受试者需要在匹配条件下按下一个按钮,并在冲突条件下按下另一个按钮。同时记录他们头皮电极的事件相关电位(ERP)。结果无论是对照组还是观察组,N270是在冲突条件下诱发的第二个刺激(S2)。观察组N270表现出比对照组波幅降低和峰潜伏期延迟。结论 N270可能是检测脑梗死后无临床症状痴呆患者认知功能障碍的一个有效指标。     

多巴胺转运蛋白基因可变数目重复序列多态性对健康成人认知电位冲突信息处理过程的影响

背景 多巴胺转运蛋白基因的一段可变数目重复序列多态性与基因的表达及转运蛋白的结合能力有关从而影响细胞外多巴胺浓度。目前关于该基因多态性对认知功能的影响的研究很少且结论很不一致。事件相关电位技术具有较高的时间分辨率, 是研究认知功能的重要手段。其中负波N270被认为是反应人脑处理冲突信息的电活动。 目的 通过比较两组具有不同多巴胺转运蛋白基因可变数目重复序列多态性的健康成人的事件相关电位来了解该多态性对大脑处理冲突信息的影响。 设计,时间,地点 DNA分析于2007年7月至2007年10月在协和医科大学分子生物学国家实验室完成。ERP测试于2007年11月至2008年4月在首都医科大学神经内科完成。 材料 Taq DNA 聚合酶购于上海博彩生物科技有限公司。ERP的采集和分析采用美国NeuroScan公司的多导脑电诱发工作站4.0版本。 方法 162名健康成人参加了多巴胺转运蛋白基因多态性的筛查,最后28人（10/10 基因型14人;10/9 基因型14人）参加了ERP测试。在ERP测试中受试者完成一个视觉比较任务：在匹配状态下一对刺激图中的第二个刺激(S2)与第一个刺激(S1)完全相同;在冲突状态下第二个刺激(S2)与第一个刺激(S1)完全不同。要求受试者在匹配状态下按一个键,在冲突状态下按另一个键。ERP在受试者进行比较任务时同步记录。 主要结果测量指标 行为学数据（反应时间和正确率）和ERP数据（ERP成分的波幅和潜伏期）。 结果 在匹配状态中,S2诱发出P300。在冲突状态中,在P300前S2还诱发出另一成分N270。无论是在匹配还是冲突状态,10/10基因型受试者的反应时间均显著快于10/9基因型受试者。10/10基因型受试者的N270潜伏期显著短于10/9基因型受试者。 结论 多巴胺转运蛋白基因可变数目重复序列多态性影响健康成人的冲突信息处理过程。     

事件相关电位N270在揭示帕金森病患者轻度认知损害中的应用

目的　寻找揭示帕金森病患者轻度认知损害的敏感指标。方法　 30例非痴呆帕金森病患者和 34名年龄匹配的正常对照参与本研究。成对的刺激 (S1和S2 )依次呈现 ,共有两种类型 :(1)S1和S2颜色匹配 ;(2 )S1和S2颜色冲突。受试者比较S1和S2颜色是否相同 ,同时在头皮记录事件相关电位。结果　无论患者组还是对照组 :颜色匹配时 ,S2诱发出P10 0、N15 0、P180、N2 0 0和P30 0 ;冲突时 ,在N2 0 0后P30 0前又出现了另一个负波———N2 70。两组间N15 0的潜伏期以及振幅均无显著性差异。患者组N2 70的峰潜伏期长于对照组 [P3,患者组 (317± 37)ms,对照组 (2 98± 31)ms];振幅低于对照组 [P3,患者组 (- 3 1± 2 5 ) μV ,对照组 (- 4 6± 2 9) μV]。患者组P30 0的峰潜伏期与对照组无显著性差异 ,仅峰振幅低于对照组。结论　非痴呆帕金森病患者存在认知功能损害 ,N2 70在检测这一认知损害时比P30 0更敏感。     

具有暴力行为的精神分裂症患者病情缓解阶段事件相关电位N270的变化

目的 初步分析事件相关电位N270在具有暴力行为精神分裂症患者病情缓解阶段中的变化特点.方法 采用颜色匹配和冲突的图片刺激对随机呈现给受试者.应用美国EGI 256导联高密度脑电仪器记录24例具有暴力行为精神分裂症患者(患者组)和25名年龄、性别匹配的健康对照(对照组)在颜色匹配和冲突图片刺激下的事件相关电位,并收集受试者在判断每对刺激的颜色是否匹配时所作出相应按键反应的正确率和反应时.结果 (1)无论在颜色匹配还是颜色冲突时,患者组和对照组正确率的差异均无统计学意义(P＞0.05),患者组的反应时长于对照组[匹配:患者组(774.17±231.25)ms,对照组(642.28±185.56)ms,t=2.206,P=0.032;冲突:患者组(835.35±246.79)ms,对照组(681.19±207.87)ms,t=2.369,P=0.022].患者组和对照组在颜色冲突状态下的反应时均长于颜色匹配状态的反应时(P＜0.05).(2)与对照组相比,患者组在F3、F4、C3、C4、Fz、Cz脑区的N270潜伏期延长(P＜0.05),波幅降低(P＜0.05).(3)与对照组相比,患者组在F3、F4、C3、Fz、Cz脑区的N270差异曲线的波幅降低(P＜0.05),F3、F4、C3、C4、Fz、Cz脑区的潜伏期延长(P＜0.05).结论 具有暴力行为精神分裂症患者在病情缓解阶段对冲突信息的加工过程存在损害,可用N270来监测和评价.     

脑干三叉神经诱发电位的刺激方法研究

目的 :研究适于术中监护的脑干三叉神经诱发电位 (BTEP)诱发方法。方法 :分别采用两种方法引导BTEP :①表面电极直接刺激下唇 ;②针状电极穿刺眶下孔直接刺激眶下神经 ,并比较其优、缺点。结果 :针状电极刺激引导出稳定的BTEP波形 ;BTEP包含3个主要波 :W1、W2 和W3 。W1为正波 ,潜伏期 0 79～ 0 85ms ;W2 为负波 ,潜伏期 1 72～ 1 80ms ;W3 为负波 ,潜伏期 2 60～ 2 65ms。结论 :针状电极刺激较表面电极刺激引导BTEP的电位记录效果为好     

大脑中汉语“介词”加工的依赖性机制：来自事件相关电位研究的证据(英文)

目的考察分析汉语中动词与介词在大脑神经加工机制上的异同。方法采用事件相关电位(event- related potentials,ERP)技术,选择以汉语为母语的正常被试者共16人,观察被试者在加工两类词时脑电的ERP波形变化。结果动词与介词的原始波比较结果表明,动词与介词在230-330ms的时间窗口均诱发一个负波,在350-500ms也均诱发一个负波,它们在峰值上均无显著差异;动词与介词的差异波比较结果表明,无论是在语义上还是句法上,发现两个类型的单词在刺激呈现后270-400ms和470-600ms的时间窗口内,在大脑两侧均诱发一个负波。结论大脑对动词与介词的加工机制没有出现显著差异,介词难以独立成类,N280也非虚词的特定性成分。     

大脑中汉语"介词"加工的依赖性机制:来自事件相关电位研究的证据

目的考察分析汉语中动词与介词在大脑神经加工机制上的异同。方法采用事件相关电位（event—relatedpotentials,ERP）技术,选择以汉语为母语的正常被试者共16人,观察被试者在加工两类词时脑电的ERP波形变化。结果动词与介词的原始波比较结果表明,动词与介词在230—330ms的时间窗口均诱发一个负波,在350-500ms也均诱发一个负波,它们在峰值上均无显著差异;动词与介词的差异波比较结果表明,无论是在语义上还是句法上,发现两个类型的单词在刺激呈现后270—400ms和470—600ms的时间窗口内,在大脑两侧均诱发一个负波。结论大脑对动词与介词的加工机制没有出现显著差异,介词难以独立成类,N280也非虚词的特定性成分。     

执行37分钟听觉Odd-ball任务中事件相关电位变化与注意的关系

背景：许多报道只是分别观察了执行Oddball任务完成过程中事件相关电位各成分的变化,没有结合实验任务模式全面分析各成分的变化及其可能存在的内在联系。 目的：通过测定健康人在执行连续37 min听觉辨别Odd-ball任务过程中的事件相关电位,分析事件相关电位各成分的变化特征与注意的关系。 设计、时间及地点：经典的37 min持续Oddball听觉辨别任务及盲法评估试验,于2003-04/2007-07在日本北九州产业医科大学康复科完成。 对象：20名健康在读大学生,全部为右利手,试验前所有学生均签署知情同意书。 方法：在执行任务过程中,学生观察以10%的概率出现的2 kHz短音靶刺激,靶刺激是随机分布于以90%的概率出现的 1 kHz短音非靶刺激之间,全部实验过程为37 min,包括1 214个声音刺激。前4 min为练习阶段,让学生熟悉任务,之后开始真正的实验过程,将其划分为阶段1,阶段2,阶段3,每阶段为10.9分。 主要观察指标：在额叶、顶叶和额顶中点采集靶刺激和非靶刺激的事件相关电位,非靶刺激包括靶刺激之前第1个和之后第1个非靶刺激的事件相关电位。除了用传统的平均加权法进行研究外,同时进行了单次P3成分分析。实验结束后,所有学生填写问卷,要求填写在各个实验阶段中的主观感受包括他们的清醒度、注意程度和对实验的兴趣程度等。 结果：①各反应电位在不同实验阶段的变化：靶刺激之前第1个非靶刺激的事件相关电位的N1波幅、靶刺激N2的波幅及靶刺激P3的波幅在实验的不同阶段发生显著变化。②不同反应电位之间的比较：靶刺激之前第1个非靶刺激的事件相关电位的N1波幅显著小于靶刺激之后第1个非靶刺激的事件相关电位和靶刺激的N1(实验阶段2、3的额叶、额顶中点和顶叶);靶刺激之前第1个非靶刺激的事件相关电位的P2潜伏期显著小于靶刺激之后第1个非靶刺激的事件相关电位的P2潜伏期(实验阶段2的额叶、额顶中点和顶叶位置上和实验阶段3的额叶);靶刺激之前第1个非靶刺激的事件相关电位的P2的波幅显著小于靶刺激之后第1个非靶刺激的事件相关电位的P2波幅(实验阶段2的额顶中点、在实验阶段3的额叶、额顶中点和顶叶);认知电位变化最敏感区在额叶。③总的平均加权的靶刺激之前第1个非靶刺激的事件相关电位波形。有正负(N1-P2)波峰复合波形,而且在刺激启动后300 ms回到基线水平,而总平均加权的靶刺激之后第1个非靶刺激的事件相关电位波形的正负(N1-P2)复合波峰的连续负波在刺激启动后450 ms之后回到基线水平(额叶和额顶中点)。④事件相关电位的单次分析显示类型2(非P3成分)出现的百分率在额叶位置上显著大于在顶叶位置(实验阶段1,2和3);类型2出现的百分率在实验阶段3的显著大于在实验阶段1(额叶和额顶中点)。⑤在各个实验阶段中,反应时间差异无显著性意义。⑥根据问卷调查,所有的被测试者均认为试验任务非常简单,测试早期处于紧张、全神贯注的状态,随着试验的进展感到轻松、单调和机械化的完成任务,注意力时有分散,但未在测试过程中入睡。 结论：在执行37 min听觉辨别任务过程中,事件相关电位各成分的变化是认知调整的结果,各成分的变化存在内在的联系,推测这种变化与被检者适应过程有关,并直接反映注意不同因素的影响。     

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。     

单相与双相抑郁患者事件相关电位P50和P300比较

目的:比较单相与双相抑郁患者事件相关电位感觉门控P50及P300的电生理差异。方法:用配对听觉条件/测试刺激范式,对57例单相抑郁患者(单相组)、63例双相抑郁患者(双相组)进行事件相关电位P50,P300测定,测量其P50的波幅,P300的潜伏期及波幅。结果:双相组P50的S2波幅显著高于单相组,而且双相组P50的抑制率显著高于单相组。双相组N2,P3潜伏期长于单相组,同时N2,P3波幅低于单相组,差异均有统计学意义。结论:双相抑郁患者认知功能损害可能比抑郁症患者更严重,事件相关电位可以为鉴别单双相抑郁提供一种新的技术手段。     

Event-related potential N270 and its distribution in adults and school-age children

To compare the pattern and distribution of event-related potential (ERP) N270 in adults and school-age children and to explore the development of conflict processing systems in the human brain, pairs of colored numbers were sequentially presented on a screen to subjects. The subjects were instructed to discriminate whether the color or magnitude of the pairs of numbers were identical (match) or different (conflict), and ERPs were recorded at the same time. In adults, a negative potential peaking at 270ms (N270) was elicited when the second stimulus (S2) conflicted with the first stimulus (S1) in either task relevant or irrelevant conditions. N270 was distributed widely on the scalp in adults. In children, N270 was only elicited by a task-relevant conflict. N270 in the color conflict was distributed bilaterally on the scalp and N270 elicited by the magnitude conflict was found to be on the left central-frontal areas. In school-age children, ERP N270 is elicited under the control of attention. Its distribution on the scalp depends on the attributes of stimulus pairs.     

Interstimulus interval effect on event-related potential N270 in a color matching task.

Event-related brain potentials were recorded in a matching task, in which subjects were asked to discriminate if the color of the second stimulus (S2) was the same as the first stimulus (S1). The interstimulus interval between the two stimuli of a pair was of three levels (150 ms, 500 ms and 1000 ms). A negative component about 270 ms after the presentation of S2 was elicited when the color of the two stimuli was not identical for the interstimulus interval of 500 ms and 1000 ms, but not for the interval of 150 ms. This may suggest that N270 represented the response of the brain to conflicting information between different cortical levels.     

Event-related potential N270 correlates of brand extension

The aim of this study is to investigate the neural mechanism of extending a brand in a specific product category to other product categories. Facing two sequential stimuli in pairs consisting of beverage brand names (stimulus 1) and product names (stimulus 2) in other categories, 16 participants were asked to indicate the suitability of extending the brand in stimulus 1 to the product category in stimulus 2. These stimulus pairs were divided into four conditions depending on the product category in stimulus 2: beverage, snack, clothing, and household appliance. A negative component, N270, was recorded for each condition on the participants' scalps,whereas the maximum amplitude was observed at the frontal area. Greater N270 amplitude was observed when participants were presented with stronger conflict between the brand product category (stimulus 1) and the extension category (stimulus 2). It suggests that N270 can be evoked not only by a conflict of physical attributes (different shapes of words of brand and product names) but also by that of lexical content. From the marketing perspective, N270 can be potentially used as a reference measure in brand-extension attempts.     

Cognitive impairment in major depressive disorder revealed by event-related potential N270.

Major depressive disorder (MDD) is a mood disorder that is often accompanied by the impairment of cognitive functions. The aim of this study was to investigate the feasibility of N270 as an index for evaluating the cognitive impairment in MDD patients. Twenty-five patients with MDD diagnosed according to DSM-IV and 25 age matched normal controls performed a matching task while event-related potentials (ERPs) were recorded from their scalp. There were two kinds of stimulus pairs in this study: match condition, the second stimulus (S2) in a pair was identical to the first one (S1); mismatch condition, S2 conflicted with S1 in the color attribute. Subjects were required to press a button in the match condition and to press another button in the mismatch condition. A negative ERP component, N270, which was considered to reflect conflict processing activity in human brain, was evoked by S2 of the mismatch condition. The patient group showed a delayed and smaller N270 than the control group. The prolongation of its peak latency was significant at P3 and P4 electrodes, and the reduction of its peak amplitude was significant at F3, F4, P3 and P4 electrodes. The amplitude of P300 elicited in the match condition was decreased in the patient group at P3 and P4 electrodes, but its latency did not differ from the control group. The results indicate that MDD patients as a group showed cognitive decline. N270 is a sensitive index in revealing cognitive impairment.     

Event-related potential N270 in detecting cognitive impairment in patients with transient ischemic attack.

Latency and amplitude of the visual P300 and N270 were examined in patients with transient ischemic attack (TIA) and in age-matched healthy control subjects to investigate the feasibility of N270 as a clinical examination method to evaluate the cognitive status of patients with TIA. Stimulus pairs with identical (match condition) or different (conflict condition) colors were randomly presented to subjects. Each pair consisted of two sequential stimuli (S1 and S2) that lasted for 300 ms; the onset interval between them was 700 ms. Thirty TIA patients without clinical dementia and 30 age-matched control subjects determined if the two stimuli in a pair had the same color. Subjects were required to press a button in the match condition and another button in the conflict condition. Event-related potentials (ERPs) were recorded from their scalp electrodes at the same time. N270 was evoked by the second stimulus (S2) of the conflict condition in either control subjects or patients. The patient group exhibited a delayed N270 than the control group. TIA patients as a group showed cognitive decline. N270 is an effective index to detect the cognitive impairment of TIA patients.     

Cognitive impairment in Parkinson's disease revealed by event-related potential N270.

Disturbed cognitive function is a well-recognized feature of idiopathic Parkinson's disease (PD). The aim of this study was to find a susceptive index to reveal the minor cognitive impairment in PD patients. Thirty PD patients without clinical dementia and thirty-four age-matched normal controls performed a matching task while event-related potentials (ERPs) were recorded from their scalp. There were two kinds of stimulus pairs in this study: match condition, the second stimulus (S2) in a pair was identical to the first one (S1); conflict condition, S2 conflicted with S1 in the color attribute. Subjects were required to press a button in the match condition and another button in the conflict condition. A negative ERP component, N270, which was considered to reflect the conflict processing activity in human brain, was evoked by the S2 of the conflict condition. The patient group showed a delayed and smaller N270 than the control group. The prolongation of its peak latency was significant at P3 and P4 electrodes and the reduction of its mean amplitude was significant at P3 electrode. The amplitude of P300 elicited in the match condition was decreased in the patient group at P4 electrode but its latency did not differ from the control group. These results indicate that PD patients as a group showed cognitive decline even in the absence of clinical dementia. N270 is a sensitive index in revealing this minor cognitive impairment.     

Event-related potential N270, a negative component to identification of conflicting information following memory retrieval

OBJECTIVE: N270, an endogenous ERP component of conflict effect, was evoked in previous studies with S1-S2 paradigm. The present experiment is designed to confirm the speculation that this conflict-related negativity could also be elicited by stimulus probes having conflict with a memorized item in a visual post-retrieval comparison task. METHODS: A Sternberg probe-matching paradigm was modified in the present study. The stimuli consisted of a memory set of 3 different items (simple figures) and a retrieval set of 3 probe figures. Subjects matched each probe to its corresponding item in the memory set. The tasks were designed with different conflict loads of no-conflict, low-conflict and high-conflict in the probe retrieval test. RESULTS: Probes of no-conflict elicited a major positive going component, P300, with bilateral parietal distribution. Probes of low- and high-conflict evoked N270, while N430 was elicited only in high-conflict condition. N270 was more negative in high-conflict condition than in low-conflict condition. The N270 was right hemispheric prominent in the low-conflict task and remarkably distributed over the right prefrontal areas. On the other hand, both N270 and N430 were distributed bilaterally on the scalp in the high-conflict task. CONCLUSIONS: The present results demonstrate that the N270 is an index to the conflict identification, while the N430 of the high-conflict task reflects the processing for complex conflicts following probe retrieval. These negativities are related to the processing of conflicts.     

Stimulus repetition and an amplitude increase of the occipital late positive component in the human visual evoked potential

VEPs to number and checkerboard stimuli were measured from F3, F4, P3, P4, Cz, O1 and O2 electrode loci. A trial was composed of 8 successive stimuli: a warning stimulus (WS) and 7 task stimuli. The task stimuli were a hexad composed of 6 identical stimuli (intratrial stimulus positions 1-6) and a single stimulus (position 7). A subject's task was either naming the numbers or pattern matching the checkerboards in the hexad and in position 7. Centrofrontal N140s and parietal N180s to the number and checkerboard stimuli did not change in amplitude across stimulus positions 1-7. Parietal and centrofrontal P350s were large in amplitude at positions 1 and 7 and decreased at positions 2-6. Parietal P270s and centrofrontal P200s to the number and checkerboard stimuli behaved in the same way as the P350s with respect to the stimulus positions. Occipital N180s to the number and checkerboard stimuli were maximum in amplitude at position 1, decreased with stimulus repetition (positions 2-6) and increased at position 7. Occipital P270s to the number and checkerboard stimuli were almost the same in amplitude at position 1. The P270 to the number stimulus increased in amplitude with stimulus repetition (positions 2-6) and decreased at position 7. The P270 to the checkerboard stimulus was the same in amplitude at positions 1-3 increased at positions 4-6 and slightly decreased at position 7. These P270 amplitude changes were interpreted as due to the amplitude changes of the overlapping occipital N250 which reflected task-specific perceptual activities.