视觉搜索中空间注意范围等级调节的早期ERP效应

对18名被试青年进行事件相关电位(ERP)实验以研究视觉空间注意范围等级效应的脑机制.采用"提示-靶"实验范式,刺激材料使用等密度排列的字母组成的3个同心圆,以去除字母排列密度不均匀对注意范围等级效应的影响.记录反应时和ERP数据.结果表明:随着提示范围的增大,识别靶刺激的反应时延长,靶刺激引起的P1,N1波幅减小.行为数据和ERP波幅的等级式变化提示视觉注意范围的等级效应,并发现该等级效应受到了来自任务难度、刺激物数量及分布等多种因素的影响.     

年老化视空间注意脑机制的研究

采用“提示目标”的视觉实验范式，通过事件相关电位（ERP）技术研究了视觉注意年老化脑机制.青年和老年被试各16名；背景由3个同心黑色圆形线条组成，提示为大、中、小不等的3个圆圈组成，刺激材料是随机选取的大写英文字母，组成3个同心圆圈.不同范围圆圈提示时，靶刺激“T”出现在相对应的圆圈，而两个干扰刺激“T” 分别呈现在对侧视野的另外两个圆圈.要求被试人根据提示寻找效应圈的靶字母“T”，并尽快尽准确地按键判断出现在左视野还是右视野.结果显示干扰刺激的存在导致靶刺激识别难度增加，引起P1的增强和N1的降低；随着提示等级的增大，两组反应时均逐渐延长，早期ERP成分P1与N1波幅均减小；与青年组相比，老年组反应时更长，后部P1增强、N1抑制，且额区P2成分亦受到显著抑制.研究结果与年老化的“复杂度效应”一致；所发现老年组P2成分的显著抑制，提示年老化可能导致视觉空间注意（非随意注意）的前脑区功能缺陷.     

视觉注意的早期等级效应与晚期半球偏侧化效应--来自ERP的电生理学证据

采用"提示-目标"的视觉实验范式,以文字提示不同等级的搜索范围,通过事件相关电位(ERP)技术研究16名青年被试的视觉注意脑机制.结果观察到随着提示等级的减小,反应时加快,早期ERP成分P1与N1波幅增大.这一结果不但提供了支持聚光灯理论的电生理学证据,而且阐明了聚光灯效应发生在信息加工早期;发现了P2效应的两个分离,一是P1效应与P2效应的分离, 表示注意的提示范围扩大, 需要额外的运算资源; 二是P2效应的左右半球分离, 提示左半球是与提示范围直接有关的注意加工的优势所在.     

不同提示条件下的视空间注意脑机制研究

采用干扰“提示目标”的视觉实验范式，分别以汉字和范围提示不同等级的搜索范围，通过事件相关电位（ERP）技术研究16名青年被试的视觉空间注意脑机制.结果发现，汉字提示的反应时明显长于范围提示，且在外部干扰条件下，范围提示的靶刺激识别速度优势更为突出；同时，范围提示和汉字提示下靶刺激识别的早期调控分别受干扰类型的影响.与范围提示相比，汉字提示下的靶刺激引起后部P1增强和N1抑制以及P2增强，外部干扰时，汉字提示与范围提示的差异不明显，而在内部干扰时，范围提示和汉字提示的差异增大，表明在靶识别难度增加（内部干扰）时，范围提示和汉字提示下的靶刺激消耗的前额叶资源有显著差异，本研究有力地证明了汉字提示与范围提示具有不同的加工机制.     

生产性噪声对工作人员脑认知影响的ERP分析

为工业企业听力保护计划制定、人机工程学设计及劳动者烦恼度缓解等提供客观的生理依据,分析了生产性噪声对工作人员脑认知的影响.采集自愿者在90 d B(A)的稳态机械性噪声刺激以及安静状态下的脑电信号,建立事件相关脑电位ERP中N1(N100)波的幅值脑地形图及P2(P200)波幅值的脑地形图,对ERP信号进行时频分析.结果表明噪声刺激与静音状态相比,ERP在N1波的幅值明显减少,而在P2波幅值变化呈相反趋势明显增加.噪声刺激下被试额区导联的N1幅值显著减小,P2幅值显著增加,表明高声压级生产性噪声导致被试烦躁、注意力分散,并干扰了认知能力.     

冥想加工性别差异的神经机制 ——来自ERP的证据

采用事件相关电位(ERP)技术,记录52名大学生被试在听(正性和负性)冥想指导语的脑电波, 探索冥想加工过程的神经机制与性别差异. 以固定频率的声音作为线索诱发N2和P3成分,这2个成分作为探究刺激差异和注意力资源调配的标记分别在160 ms和240 ms的时间上观察到. 结果表明:在正性冥想条件下,在前额叶皮层(PFC)中观察到的N160波幅更大,而在负性冥想条件下,P240波幅减小;在负性冥想条件下,表现出明显的性别的差异,主要是情绪偏侧化加工更加明显,男性在N160左额叶波幅显著大于右额叶,女性在P240右额叶波幅显著大于左额叶. 结果为冥想的作用存在性别差异进一步提供神经生理方面的证据.     

短时太极(八法五步)对大学生负性情绪刺激下抑制功能影响的ERP研究

为探讨短时太极(八法五步)干预对大学生负性情绪下抑制功能的影响及其神经机制.本研究以24名大学生为研究对象,随机分为负性情绪刺激组(负性组)、中性情绪刺激组(中性组),各组12人(男6女6),测量情绪刺激前后的抑制功能并同步采集ERP数据.对负性组进行一次60 min中等强度的太极(八法五步)运动干预,干预后再次测量其情绪刺激前后的抑制功能并同步采集ERP数据.结果表明:1)运动干预前不同情绪刺激对抑制功能影响的差异为:①在反应时上,情绪刺激前,负性组与中性组在各任务(一致、不一致、抑制冲突)上的反应时均无显著性差异;情绪刺激后,负性组比中性组在各任务上的反应时均显著延长;负性组情绪刺激后较刺激前在各任务上的反应时均非常显著延长;中性组情绪刺激后较刺激前在各任务上的反应时均无显著差异.表明负性情绪刺激降低了抑制功能的运行效率.②在N2振幅上,情绪刺激后,负性组比中性组在一致、不一致任务上前额叶N2振幅均显著减小,表明负性情绪刺激降低了抑制功能任务出现后200 ms左右前额叶的电压值.2)短时太极(八法五步)干预对负性情绪刺激下抑制功能的影响为:①负性组干预后较干预前在各任务(一致、不一致、抑制冲突)上的反应时均显著缩短,表明干预后抑制功能的运行效率显著提升;②负性组干预后较干预前在一致、不一致任务上前额叶N2振幅较均显著增大,表明运动干预后抑制功能任务出现后200 ms左右前额叶的电压值显著增大.综上可知:负性情绪刺激对抑制功能具有干扰作用,其神经机制是前额叶区N2振幅降低;短时太极(八法五步)能够降低负性情绪刺激对抑制功能的干扰,其神经机制是前额叶区N2振幅增大;太极(八法五步)是降低负性情绪刺激对抑制功能干扰的有效手段.     

分类活动中的认知控制：一项事件相关电位研究

采用事件相关电位(ERP)探索了分类过程中认知控制的神经机制.以几何图形为刺激材料设置两类任务：包含冲突抑制的分类任务和不包含冲突抑制的分类任务.将两类任务诱发的脑电分别进行叠加和平均，并将两者相减得到差异波.在200到500ms范围包含冲突抑制的分类任务比不包含冲突抑制的分类任务诱发的ERP波形表现出更为负向的偏移.差异波波峰潜伏期约为340ms(N340).地形图显示N340在右侧额中央区活动最强(FCz点).偶极子源定位分析结果显示，N340可能起源于扣带前回.由于两类任务中相同的是分类任务的吻合提取加工，所以两类任务的差异波反映的是除吻合提取之外的加工，即抑制控制加工，因此N340可能反映了高级认知活动(如分类)中认知控制.     

多重位置上的返回抑制:对注意动量说的质疑

采用多重线索范式在返回抑制容量研究中鉴别注意动量说与抑制说.实验一探讨了中央线索对返回抑制容量的作用,发现中央线索与线索数量的随机化均能独立增大返回抑制量.实验二和三分别探讨了线索时间对序列和同时线索条件下的返回抑制容量的影响,发现随线索时间的增加,相隔序列线索条件下的返回抑制容量逐渐增加,而对相邻序列线索条件的影响较弱.实验结果不支持注意动量说,倾向于支持抑制说.     

多重位置上的返回抑制:对注意动量说的检验

采用多重线索范式在返回抑制容量研究中鉴别注意动量说与抑制说. 实验一探讨了中央线索对返回抑制容量的作用，发现中央线索与线索数量的随机化均能独立增大返回抑制量. 实验二和三分别探讨了线索时间对序列和同时线索条件下的返回抑制容量的影响，发现随线索时间的增加，相隔序列线索条件下的返回抑制容量逐渐增加，而对相邻序列线索条件的影响较弱. 实验结果不支持注意动量说，倾向于支持抑制说.     

内隐还是外显记忆: 对女性面孔吸引力记忆偏好的ERP研究

运用事件相关电位(ERPs)技术, 采用学习-再认的实验范式, 考察38名大学生(21名男生和17名女生)对女性面孔吸引力再认记忆的认知神经机制。结果发现大学生对女性面孔吸引力的记忆偏好存在性别差异, 再认任务中有吸引力的女性面孔诱发了男性更负的早期ERP成分(N90, N220和N300), 而对女性的效应并不显著。这可能与两性在遗传基因、性激素、大脑结构与功能上的不同有关。进一步对男性的记忆特点进行分析发现, 内隐记忆效应在N80和LPC(300~600 ms)上表现显著, 其最强效应出现在中央区和顶区; 外显记忆效应在P170和LPC(400~600 ms)上表现显著, 其最强效应出现在前额区和额区。表明男性对有吸引力女性面孔的记忆偏好效应更大, 且内隐和外显记忆的脑机制在单一的再认任务中产生了分离。     

儿童Stroop效应加工阶段特点的事件相关电位研究

选用小学六年级儿童为被试者,采用事件相关电位研究了Stroop效应的时间进程。实验中要求被试者判断在计算机屏幕中央出现的汉字颜色,并尽可能又快又准地按下相应的键,同时使用32导电极帽记录被试者的脑电信号。结果除了发现反应时的Stroop效应;还发现在汉字出现后大约300 ms左右,颜色与语义不一致的汉字诱发的P300比其它两种条件的波幅要大、潜伏期要晚;在汉字出现大约400 ms之后引发了一个慢波,不一致条件和控制条件引起的慢波波幅在头皮顶部比一致条件大。结果说明儿童Stroop效应的产生是一个复杂过程,干扰效应是早期颜色识别和后期反应选择两个阶段共同作用的结果,而促进效应则发生在后期的反应选择阶段。     

An ERP study for the degrees of the difficulty in visual search

The present study mainly probed the relationships between ERP components and the degrees of difficulty in visual search. Three experimental and one controlled conditions were randomly selected. Results showed that the P1, N1, and P2 amplitudes and latencies had no significant differences among the three experimental and one controlled conditions, and the ERP waveforms of low perceptual load of visual search were different from that of high perceptual load. These results might indicate that the latencies and amplitudes of initial P1, N1 and P2 in high and low perceptual load conditions were almost the same. The ERP waveforms of parallel search were very different from that of serial search, and the ERP waveforms of serial search were very similar. The P3 amplitudes increased as the degrees of the difficulty in visual search decreased.     

An ERP study for the degrees of the difficulty in visual search

The present study mainly probed the relationships between ERP components and the degrees of difficulty in visual search. Three experimental and one controlled conditions were randomly selected. Results showed that the P1, N1, and P2 amplitudes and latencies had no significant differences among the three experimental and one controlled conditions, and the ERP waveforms of low perceptual load of visual search were different from that of high perceptual load. These results might indicate that the latencies and amplitudes of initial P1, N1 and P2 in high and low perceptual load conditions were almost the same. The ERP waveforms of parallel search were very different from that of serial search, and the ERP waveforms of serial search were very similar. The P3 amplitudes increased as the degrees of the difficulty in visual search decreased.     

Relationship between prospective memory and vigilance: Evidence from ERP

Event-related potentials (ERPs) were used in this study to investigate the neural correlates of prospective memory (PM) and vigilance. Twenty college or graduate students participated in this study. They were administered a PM and a vigilance task and physiological data were collected at the same time. Behavioral results showed that the RT associated with PM cues was longer than those associated with vigilance targets. ERP results showed that PM cues and vigilance targets did not show significant difference in the N2 but PM cues evoked greater N300 than vigilance targets, and vigilance targets evoked greater parietal positivity/P3 than PM cues, suggesting vigilance and PM have similar but also distinctive neural basis.     

脑损伤后综合征患者脑CT与事件相关电位的研究

探讨脑损伤后综合征患者的事件相关、脑CT和认知功能。应用听觉oddball序列刺激的事件相关电位方法对脑损伤后综合征患者30例（病人组）,健康人30例（对照组）进行比较。病人组较对照组P3潜伏期延长,波幅降低,经统计学处理有显著性差异（P＜0．05）。病人组脑CT检查有病灶者P3潜伏期延长,波幅降低更显著。事件相关电位检测和头频CT对研究损伤后综合征患者的认知功能变化有重要作用。     

Neural mechanisms of unconscious visual motion priming

The neural correlates of the motion priming were examined in normal young subjects using event-related brain potentials (ERPs) and functional magnetic resonance imaging (fMRI). Visual motion perception can be uncon-sciously biased in favor of a particular direction by a pre-ceding motion in that direction. Motion priming first in-volved an enhancement of ERP amplitude about 100 ms fol-lowing the onset of motion. The amplitudes of ERP compo-nents after 350 ms were also increased. The fMRI results suggest that the early-latency effect reflects modulation of neural responses in extrastriate cortex. Higher-level visual processing areas, including cortical regions MT/MST and the intraparietal cortices were also activated. The findings provide direct evidence that unconscious priming of motion perception is the result of interaction of direction-selective neural responses to motion stimuli. The results cannot be accounted for by refractoriness of neural responses, but in-stead support a theory of motion priming based on motion opponency, as proposed in computational models.     

Brain dynamic mechanisms on the visual attention scale with Chinese characters cues

The temporal dynamics in brain evoked by the scale of visual attention with the cues of Chinese characters were studied by recording event-related potentials (ERPs). With the fixed orientation of visual attention, 14 healthy young participants performed a search task in which the search array was preceded by Chinese characters cues, “大, 中, 小” (large, medium, small). 128 channels scalp ERPs were recorded to study the role of visual attention scale played in the visual spatial attention. The results showed that there was no significant difference in the ERP components evoked by the three Chinese characters cues except the inferoposterior N2 latency. The targets evoked P2, N2 amplitudes and latency have significant differences with the different cues of large, middle and small, while P1 and N1 components had no significant difference. The results suggested that the processing of scale of visual attention was mainly concerned with P2, N2 components, while the P1, N1 components were mainly related with the processing of visual orientation information.