注意对人体大脑听觉诱发电位晚成分的影响

本工作在尽量减少其它对注意过程可能发生影响的心理因素的实验条件下,于同一组被试同时研究了选择性注意与实验次序对人体大脑听觉诱发电位晚成份的影响。观察到:选择性注意使N_1波与P_2波潜伏期延长,波幅增高;P_3波波幅增高。先试组N_1波潜伏期延长,波幅增高;P_2、N_2、P_3波波幅增高。实验中观察到一些不符合刺激强度规律的现象。对实验结果进行了讨论。     

再探猜谜作业中“顿悟”的ERP效应

采用事件相关电位(ERP)技术探讨顿悟问题（字谜）解决中提供答案后的脑内时程动态变化。结果发现,在250~400 ms内,“有顿悟”和“不理解”比“无顿悟”的ERP波形均有一个更为负向的偏移。在“有顿悟—无顿悟”和“不理解—无顿悟”的差异波中,这个负成分的潜伏期约为320 ms (N320),地形图显示,N320在中后部活动最强。进一步对“有顿悟—无顿悟”差异波作偶极子溯源分析,发现N320主要起源于扣带前回（ACC）附近。这似乎表明,N320可能反映了提供答案瞬间新旧思路之间的认知冲突,但是却不能真正揭示顿悟问题解决中思维定势的成功突破以及“恍然大悟”所对应的独特脑内时程变化     

双关图作为面孔刺激与非面孔刺激对大脑事件相关电位的影响

用线条描绘的图形作为刺激材料,A为老鼠,C为老头,B为双关图(ambi-guous figure)。图形按两种顺序:A→B→C(Ⅰ)和C←B→A(Ⅱ)向被试呈现,每次呈现时间100ms。被试按刺激呈现方式分成两组,每组20人。被试接受图形的同时记录事件相关电位(ERPs),B图呈现后要求被试报告观察内容。对主观报告考验,发现双关图在Ⅰ呈现方式中作为非面孔刺激(老鼠)被认知,在Ⅱ呈现方式中作为面孔刺激(老头)被认知。ERPs分析表明,双关图作为面孔刺激被识别时,T_3、Pz的P_2波潜伏期比双关图作为非面孔刺激被识别时分别延长6.09ms和7.39ms,波幅没有显著差异;双关图作为面孔刺激时T_3、T_4、Pz和Oz的P_3波的潜伏期比双关图作为非面孔刺激时延长约15ms;波幅没有显著差异。     

时间结构和速度线索对碰撞时间估计的影响

估计被遮挡的运动物体何时到达某一特定位置称为碰撞时间估计。本研究利用遮挡范式,通过控制时间结构、物理速度及运动过程是否可见设计两个（2物理速度×3时间结构）实验来探究三者对碰撞时间估计的影响。结果：当时间结构一致时,不论物理速度快慢及是否存在视觉速度线索,被试的绩效都没有显著差异;当时间结构不一致时,不论物理速度快慢,存在视觉速度条件下被试的绝对偏差小于无视觉速度条件。结论：时间结构一致时,被试主要使用时间线索进行碰撞时间估计;时间结构不一致时,被试通过整合时间结构和视觉速度线索进行估计。     

人脑加工自我参照任务的时空特点:来自ERP的证据

以自我参照加工任务为范式,实验采用事件相关电位(ERP)技术,探讨了自我参照加工中符合判断和不符合判断加工的时间进程和大脑神经机制。结果发现,自我参照加工在时间上可以概括分为三个阶段:注意分配阶段N1(80~150 ms)波幅出现自我参照结果的差异;语义整合阶段N2(250~450 ms)波幅和潜伏期出现自我参照结果的差异;评价判断阶段P3(450~700 ms)波幅和潜伏期出现自我参照结果的差异。从我们选择的大脑兴趣区激活水平上分析发现,自我信息在大脑中的激活似乎是一个由右及左,由后及前再及后的动态变化过程。研究结果丰富了自我参照加工的已有结果,并且对未来研究具有一定的启示意义。     

视觉搜索有记忆参与

采用动态搜索任务,系统改变刺激项位置变换的速度,探讨视觉搜索是否有"记忆"参与.结果发现:(1)刺激项位置的变换速度较快时(120 ms/次、220 ms/次),动态搜索的搜索效率显著低于静态搜索;(2)刺激项位置的变换速度较慢时(420 ms/次),动态搜索的搜索效率与静态搜索无差异.该结果表明视觉搜索有"记忆"参与,返回抑制可能是视觉搜索中"记忆"的内在机制.     

延迟时间与预先信息对任务切换的作用

对切换代价的本质存在任务设置惯性和任务设置重构两种观点。为揭示二者在切换代价中的关系, 研究了不同延迟时间条件下预先信息对任务切换的作用, 结果发现：(1)延迟时间对切换代价有显著影响, 100 ms的切换代价显著高于1000 ms的切换代价, 而600 ms分别与100 ms、1000 ms之间的切换代价无显著差异; (2)预先信息对切换代价的影响显著, 全部信息的切换代价显著低于无信息和部分信息的切换代价, 而后二者之间无显著差异; (3)延迟时间与预先信息无交互作用。这表明, 延迟时间与预先信息分别作用于任务设置惯性和任务设置重构, 切换代价反映了这两种具有相加效应的加工过程。     

手机短信与大学生人格特征关系的研究

采用自编式手机短信（SMS）问卷及NEO—PI—R人格测试,以280名大学生为研究对象,该研究考察了SMS使用情况与大学生人格特征的关系。结果表明：（1）神经质与使用SMS的担心时间、幻觉经验、作息时间有显著负相关,与SMS对交往的影响呈显著的正相关;（2）外倾性与SMS使用数量和作息时间显著正相关;（3）宜人性与SMS使用时间有显著负相关,而与SMS比例呈显著正相关;（4）认真性与总费比例有显著负相关,与幻觉经验和作息时间存在显著正相关。     

心理性应激的时间加工进程:来自ERP的证据*

采用有时间压力的算术题目诱发被试的心理性应激体验,并用事件相关电位技术(ERP)探讨心理性应激发生时大脑神经活动的时程变化。行为数据结果发现有时间压力下被试的反应时更短;脑电数据结果发现有时间压力组的容易题目比无时间压力组的容易题目诱发出更大的N1峰值、更长的P2潜伏期和更大的P300波幅;有时间压力组的困难题目比无时间压力组的困难题目同样诱发出更大的N1峰值、更长的P2潜伏期和更大的P300波幅,但这种组别主效应仅表现在部分电极点上。该研究结果表明心理性应激增加了早期知觉加工的负载,导致知觉加工速度减慢,在信息加工后期阶段需要占用更多的认知资源。     

视觉符号否定的加工进程

本研究采用图-词匹配的判断任务探讨视觉符号否定的加工机制, 设计3个实验, 分别探讨视觉符号否定在加工早期(250 ms)、中期(750 ms)及晚期(1500 ms)的心理模拟特点。结果发现, 在视觉符号否定加工的早期、中期及晚期, 与真实状态匹配的否定相关词的反应时都显著快于与被否定状态匹配的肯定相关词。该结果表明, 与文字符号否定加工的两步模拟假设不同, 在视觉符号否定的加工中, 被试在早期就模拟了事件的真实状态, 并在中期和晚期一直保持该状态的表征, 符合一步模拟假设; 此外, 被否定信息加工的抑制/保存假设得到支持。     

Effects of angularity of the figures with sharp and round corners on visual evoked potentials

Following a study in which equilateral triangles elicited larger visual evoked potentials (VEPs) than either squares or circles, we examined the effect of single-line angular figures with a sharp or a round corner at angles of 45°, 90°, 135° or 180°. VEPs were recorded monopolarly at four locations on the midline of scalp for 10 subjects, while the figure was tachiscopically presented to the lower visual field. Subtracted waves were obtained between figure and control (blank) conditions. N1 (peak latency 135–142 ms) and P2 (235–237 ms) waves were identifiable. N1 amplitude tended to decrease as a function of angularity, irrespective of orientation (angle pointing up or down). The effect of the sharpness/roundness of the corner was much smaller than that of its angularity. These findings suggest that the greater VEP response with triangles than with squares and circles may be attributable to the acute angularity of triangles. Related cortical processes and VEP components are also discussed.     

Visual evoked potentials elicited by subjective contour figures

In order to investigate the relationship between the appearance of illusory figures and the wave form of visual evoked potentials (VEPs), 8 different visual pattern stimuli were presented to 8 normal subjects. Four of the stimuli (experimental stimuli) produced subjective figures and contours (squares and discs). The 4 other stimuli (reference stimuli), although equal to the experimental stimuli in the amount of physical energy, did not produce the illusion of squares or discs. Electrodes were placed on the scalp at central and occipital locations. Three prominent peaks in the occipital record were observed in all subjects. An amplitude difference of VEP N180 (N2) between the subjective figures and the reference stimuli was found in the values for each subject. Enhancement of the VEP of the illusory figure stimuli was observed for a specific component (N2), whereas the amplitude values at the central components and the occipital P120 (P2) and P280 (P3) were almost the same as the reference values. The VEP (N2 component) amplitude enhancement at the occipital area for subjective figure stimuli suggests that illusory contour formation takes place at higher levels in the visual system. This was known from experiments using dichoptic presentation.     

Time-course of hemispheric preference for processing contralateral relevant shapes: P1pc, N1pc, N2pc, N3pc

A most sensitive and specific electrophysiological indicator of selective processing of visual stimuli is the N2pc component. N2pc is a negative EEG potential peaking 250 ms after stimulus onset, recorded from posterior sites contralateral to relevant stimuli. Additional deflections preceding or following N2pc have been obtained in previous studies, possibly produced by specific stimulus features or specific prime-target sequences. To clarify the entire time-course of the contralateral- ipsilateral (C-I) difference recorded from the scalp above visual cortex in response to left-right pairs of targets and distracters, C-I differences were here compared between two types of stimuli and between stimuli that were or were not preceded by masked neutral primes. The C-I difference waveform consisted of several peaks, termed here P1pc (60-100 ms after target onset), N1pc (120-160 ms), N2pc (220-280 ms), and N3pc (360-400 ms). Being markedly enhanced when stimuli were preceded by the neutral primes, P1pc may indicate a response to stimulus change. Also, when stimuli were primed, N2pc reached its peak earlier, thereby tending to merge with N1pc. N3pc seemed to increase when target discrimination was difficult. N1pc, N2pc, and N3pc appear as three periods of one process. N3pc probably corresponds to L400 or SPCN as described in other studies. These observations suggest that the neurophysiological basis of stimulus-driven focusing of attention on target stimuli is a process that lasts for hundreds of milliseconds, with the relevant hemisphere being activated in an oscillating manner as long as required by the task.     

不同愉悦度面孔阈下情绪启动效应:来自ERP的证据

采用事件相关电位技术,研究阈下情绪启动效应。实验中的因素是阈下呈现的情绪启动面孔的愉悦度,分为高、低两个水平。被试的任务是对中性靶刺激面孔进行情绪判断。结果发现:被试在对靶刺激进行情绪判断时出现与启动刺激愉悦度趋于一致的启动效应;低愉悦度面孔作启动刺激条件下N1和P2的波幅显著大于高愉悦度面孔作为启动刺激的条件;不同愉悦度情绪面孔的阈下启动效应是由于启动刺激影响了对靶刺激的知觉加工所致。     

自我-他人重叠影响疼痛共情的ERP研究

为探究自我-他人重叠影响疼痛共情的神经机制,记录并分析被试在高、中、低重叠程度条件下共情判断的脑电活动。发现在早期N2上,重叠程度三水平间差异显著,表现为密友＜熟人＜陌生人（密友与熟人差异边缘显著）;在晚期P3上,疼痛条件下重叠程度间呈显著差异,密友比熟人、陌生人显著要大;在LPP上疼痛条件诱发更大波幅。表明早期阶段（N2）区分不同重叠程度,可能是对威胁性刺激的检测阶段,自我-他人重叠程度影响共情加工晚期阶段（P3）的社会认知评价加工。     

自我-他人重叠影响疼痛共情的ERP研究

为探究自我-他人重叠影响疼痛共情的神经机制,记录并分析被试在高、中、低重叠程度条件下共情判断的脑电活动。发现在早期N2上,重叠程度三水平间差异显著,表现为密友＜熟人＜陌生人（密友与熟人差异边缘显著）;在晚期P3上,疼痛条件下重叠程度间呈显著差异,密友比熟人、陌生人显著要大;在LPP上疼痛条件诱发更大波幅。表明早期阶段（N2）区分不同重叠程度,可能是对威胁性刺激的检测阶段,自我-他人重叠程度影响共情加工晚期阶段（P3）的社会认知评价加工。     

VEP latency and some properties of simple motor reaction-time distribution

Summary The median of simple motor reaction (RT) to a flash parallels the latencies of visually evoked potential (VEP) deflections if flash intensity is varied. However, mean and median reaction times are not equal because of the skewness of RT distribution. It therefore seemed plausible that the mean reaction time — intensity relationship would be steeper than that for VEP latency. Such divergence would account for the intensity-dependent motor component of RT revealed by other psychophysical studies. The latencies of VEP deflections were measured as a function of intensity and the results were compared with mean and median RTs. The difference between mean and median RT is constant and independent of flash intensity. Moreover, both values are parallel to VEP latency. The general pattern of results remains the same after a change in the distribution from which the foreperiod is sampled.     

异同判断中“快同效应”的大脑机制：一项ERP研究

采用高密度的事件相关电位（ERPs）技术,记录分析了大学生被试在执行异同判断任务[包括不同颜色刺激对（DC）,不同形状刺激对（DS）和相同刺激对（Same）]时的脑内时程动态变化。行为结果表明,“同”反应的确显著快于“异”反应,表现出明显的快同效应。ERP结果显示：在280-320 ms内,DS和DC条件均比Same条件诱发一个更负的N2成分。偶极子溯源分析表明,DC和DS条件下,N2可能起源于大脑的前扣带皮层（ACC）,可能与“异”反应早期不一致信息（颜色或形状）的认知监控和调节有关;反之Same条件下,N2成分可能起源于楔前叶,主要反映了“同”反应早期知觉识别中整体特征比较加工的过程（同一性指示器）。另外,在450 ms左右, DC和DS比Same条件均诱发了一个更负的P3成分,可能反映了对刺激局部特征的比较和识别（慢速比较器）,并与选择性注意和资源分配等高级认知活动有关;并且,Same条件下P3成分的潜伏期更短,与行为结果一致。以上研究结果表明,异同判断中“同”反应和“异”反应可能有着不同的比较通道和大脑机制,支持双过程模型理论;同时表明,慢速比较器和同一性指示器可能是序列加工的。     

网球运动专长对深度运动知觉影响的ERP研究

结合专家-新手范式与ERP技术,研究网球运动专长对个体深度运动知觉产生的影响。通过记录网球专家和新手各19名进行深度运动模式判断时的行为和ERP数据,比较两组个体深度运动知觉的行为反应差异和脑电特征。结果显示,网球专家组深度运动知觉的判断准确率高于新手组;新手组在球体靠近时P1(PO7点)的潜伏期比球体远离时的潜伏期长,专家组无显著性差异;专家组在球体靠近时的P2(Oz点)成分潜伏期长于球体远离时的潜伏期。结果表明,网球运动专家的深度运动知觉能力在准确性上较新手高;运动专长效应与选择性注意资源的调用以及模式识别有关;枕区P2成分可作为深度运动知觉的评价指标。     

不同加工与记忆编码关系的ERP研究

通过事件相关电位(ERPs)记录,探讨了深、浅2种加工与记忆编码的相互关系。研究结果表明,（1）在深、浅两种加工条件下,首次使用汉字材料,获得了ERP相继记忆效应（Dm),随后再认正确的ERPs比随后再认不正确的ERPs有更大的晚正成分。（2）深加工的Dm效应始于N2波的前支（230－280ms)和N2波之后（395－800ms);而浅加工的Dm效应发生在345－490ms之间。深、浅加工的Dm效 涉及不同的脑区,这一结果支持深、浅两种加工的Dm效应可能是分离的结论。