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。     

孤独症儿童面孔熟悉性识别的ERP研究

目的：探讨孤独症儿童与普通儿童在面孔熟悉性识别上的差异。方法：以中性表情的熟悉人面孔、陌生人面孔为刺激材料,选择儿童喜欢的物件照片作为靶刺激,采用32道事件相关电位仪,分别记录24例孤独症儿童与27例普通儿童的诱发脑电活动,比较两类儿童在不同刺激下的脑电变化。采用SPSS13．0进行数据处理分析。结果：孤独症儿童组按键任务反应时较普通儿童组延长（P〈0．05）,正确率无差别（P〉O．05）;两组儿童在刺激呈现后约220ms颞枕叶导联出现延迟的先行负波170（PrN170）,两组间对于不同类型的面孔刺激,PrN170波幅与潜伏期均未见差异（P〉0．05）;在枕叶导联260～320ms,面孔刺激诱发孤独症儿童产生波幅更大的正波,差异有显著意义（P=0．047）;在400～600ms,两组儿童对于面孔刺激的平均波幅在多处导联出现差异（P〈0．05）,其中在前部导联最明显。本试验两组儿童均未发现熟悉人面孔以及陌生人面孔间的波形差异（P〉0．05）,两种面孔的差异波在两组儿童各导联中均未见差异（P〉0．05）。结论：孤独症儿童面孔认知的后期加工模式与普通儿童有所差异。     

靶与非靶刺激信息的认知事件相关电位比较

对靶与非靶刺激信息的认知事件相关电位进行比较研究。给予受试者汉语词汇作业刺激，被视觉感知，靶刺激以２０％的概率随机呈现，非靶刺激占８０％。结果发现这两种刺激状态下认知事件相关电位成分的Ｎ１，Ｐ２，Ｎ２无显著差异，而Ｐ３，Ｎ４和ＬＰＣ（ＬａｔｅＰｏｓｉｔｉｖｅＣｏｍｐｏｎｅｎｔ）则其波形变化和地形图特征有明显不同，靶刺激激活整个脑区，各波幅均较大，以Ｐ３波最为显著     

3D电视图片视差引发的EEG和VEP变化的研究

采集志愿者观看3D电视不同视差图片时的脑电信号,分析其在观看过程中产生的视觉诱发电位,计算各波段功率得到视觉疲劳因子R值,以此来探究3D影片中视差因素对人体健康的影响,为3D片源的制作提供一定的指标参考。基于Neuroscan脑电仪搭建实验系统,选取10名健康志愿者观看不同视差的3D图片,采集脑电信号的同时当其感觉不适时（刺痛感或者眩晕感）通过按键反馈。对采集的脑电信号中枕部视觉功能区的O1、Oz、O2等3个导联的数据采取叠加平均的方法提取其视觉诱发电位(VEP),得到N₁₃₅成分波和P₂₆₀成分波;将预处理后的脑电信号依照相同的图片刺激序号进行叠加,将结果用Matlab的EEG工具包进行相对功率计算,进一步得到疲劳因子R值。结果表明,不同视差图片诱发的VEP的电位幅值和潜伏期有所差异,潜伏期的差异尤为明显（不同分组的均值变化为30%）;志愿者观看只有负视差的3D图片时疲劳因子R值较大,即所有导联的均值比其他分组图片高10%。P₂₆₀成分的幅值和潜伏期可以作为评价3D片源的一个参考指标;负视差的图片更容易引起人眼的疲劳;正负视差都有的图片引起的疲劳度等级最低。     

家兔P_(300)—like电位的初步研究

我们把oddball poradingm 与强化刺激相结合,在家兔记录到一个与人类P_(300)相当的电位即P_(300)—like电位。该电位头颅分布广泛,无半球间及额、顶叶差异。家免P_(300)—like电位呈“双峰”即P_(250)—N_(290)—P_(360)。分别测量三波潜伏期依次为     

注意状态对事件相关电位的影响研究

目的：研究不同注意状态下事件相关电位的变化特点。方法：智能正常年轻人18例，采用oddball模式，非靶刺激为80％的750Hz低频短音，靶刺激为20％的2000Hz高频短音。利用Nicolet Pathfinder Ⅱ型诱发电位仪，记录主动分辨靶刺激时，计数／不计数状态下事件相关电位各波潜伏期和P3波幅的变化。结果：与计数靶刺激时比，在不计数时P3波幅显著降低（P＜0．01），P3潜伏期及其余各波潜伏期变化无显著性意义。结论：P300波幅与注意密切相关，P3潜伏期不易受被试注意力的影响，是一个稳定的测量认知功能的指标。     

体感电刺激诱发事件相关电位的研究

目的对视觉、听觉、体感3种不同模态下靶刺激诱发的事件相关电位(ERP)进行比较研究,探讨体感电刺激作为脑机接口(BCI)一种新的信号诱发模式的可能性,为基于体感ERP的BCI研究提供理论依据。方法选择17例视力或矫正视力正常、听力正常、躯体感觉正常且无任何大脑病史的被试者,其中男性8例,女性9例;年龄20~26岁,平均年龄22.6岁;均为右利手。分别记录17例健康的被试者在视觉、听觉、体感单通道靶刺激下诱发的脑电图;对3类靶刺激下ERP的时域参数(幅值、潜伏期)、行为学数据(反应时间、错误率)、脑源定位进行比较分析。结果 3类靶刺激模式下的ERP波形具有相似性,体感电刺激诱发的ERP幅值与视觉、听觉靶刺激相比无显著性差异;体感电刺激诱发ERP的峰值潜伏期显著长于视觉靶刺激;体感电刺激的反应时间显著长于视觉靶刺激,错误率也高于视觉、听觉靶刺激;体感电刺激诱发ERP的脑内源与视觉靶刺激相比具有相似性。结论相比于视觉、听觉靶刺激,大脑对于体感电刺激的探测难度高,敏感程度低;但从ERP的波形和幅值上看,体感电刺激可以诱发出稳定的、可被检测到的ERP波形,完全有可能应用于BCI系统作为一种新的ERP诱发模式。     

躯体化障碍患者针灸治疗后事件相关电位P_(300)及睡眠脑电的变化

目的 :探讨事件相关电位P_(300)及Quisi在躯体化障碍患者睡眠障碍评估中的价值。方法 :应用脑电生理仪对91例躯体化障碍(SFD)患者分别在治疗前和治疗后7周进行P_(300)和Quisi检测,使用匹兹堡睡眠质量指数量表(PSQI)等测定患者的睡眠障碍。选择94例正常志愿者作为对照组。结果 :(1)共纳入研究的91例SFD中,按症状出现频率从高到低依次为睡眠、认知功能、心血管系统、运动系统、消化系统、泌尿生殖系统、呼吸系统及五官不适症状。(2)治疗前躯体化障碍组有明显的睡眠缺损,其PSQI≥14分。与对照组比较,SFD组患者事件相关电位成分中P_3靶潜伏期延长,靶P_2、P_3波幅低,非靶P_2波幅低(P0.01),同时Quisi异常。治疗后,随着躯体化障碍患者睡眠的恢复,事件相关电位成分中P_3潜伏期缩短,P_3波幅增高及Quisi有所恢复(P0.05或0.01)。结论 :针灸治疗能改善睡眠质量。Quisi及P_(300)联合运用有助于反映躯体化障碍患者睡眠的变化,Quisi及P_3指标的变化较有临床应用价值。     

听觉-体感觉靶刺激诱发事件相关电位跨模增进效应研究

目的研究听觉-体感觉跨模靶刺激模式下双模增进作用,探讨大脑认知过程不同脑区间相互作用的神经机制。方法选择20例听力正常、躯体感觉功能正常、无任何大脑病史的在读研究生和大学生,其中男性8例,女性12例;年龄20~26岁,平均年龄22.5岁;均为右利手。以受试者的事件相关电位为考察对象,分析听觉-体感觉跨模靶刺激与单一听觉、体感觉靶刺激模式下受试者的行为学数据(反应时间、反应错误率)与事件相关电位(P3、P2幅值和潜伏期)的关系。结果单一听觉、体感觉靶刺激模式下受试者的反应时间[分别为(538±14)ms、(576±18)ms]、P3峰值潜伏期[分别为(455±17)ms、(479±18)ms]均显著大于听觉-体感觉双模靶刺激模式下的值[反应时间(461±20)ms,潜伏期(357±12)ms;P0.001];单一听觉、体感觉靶刺激模式下受试者的反应错误率[分别为(5.1±1.2)%、(19.3±3.1)%]显著小于听觉-体感觉双模靶刺激模式下的值[(2.7±0.6)%;P0.001],说明大脑不仅对听觉-体感觉双模靶刺激有更快的反应速度,而且探测的准确度明显优于单一靶刺激;不同靶刺激模式下,反应时间与P3峰值潜伏期具有显著相关性(r=0.58,P0.001),可以作为跨通道增进效应潜在神经过程的时间指标。结论双模靶刺激模式下存在明显的增进效应,大脑在跨模靶刺激模式下具有更优越的感觉信号神经整合机制。     

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。     

正常人的视觉事件相关电位研究

本文利用三种视觉符号编排的刺激序列，记录了９５名正常人的视觉ＥＲＰ，报道了Ｆｚ、Ｐｚ点Ｎ２、Ｐ３波幅和潜伏期的正常值及Ｎ２、Ｐ３的影响因素。结果表明：该刺激序列可引出清晰、稳定的ＥＲＰ波形；Ｐ３波幅与任务和部位有关，靶Ｐ３波幅大于非靶Ｐ３，靶Ｐ３于Ｐｚ点波幅大于Ｆｚ，非靶Ｐ３在Ｆｚ、Ｐｚ点间波幅无明显差异；Ｎ２波幅与任务无关，靶与非靶之间Ｎ２波幅无差异，而与部位有关，Ｆｚ点波幅大于Ｐｚ点；Ｎ２、Ｐ３受年龄的影响．中老年人Ｎ２、Ｐ３潜伏期长于青年人，而波幅中老年人较青年人低。     

Left temporal deficit of P300 in patients with schizophrenia: effects of task.

P300 is often, but not always, observed to be more reduced over left than right temporal lobes in patients with schizophrenia. The possibility that task differences contribute to the inconsistency in the literature was explored in this study. ERPs were collected from 17 right-handed men with schizophrenia (DSM-IIIR) and 11 right-handed healthy male community controls, performing three auditory oddball tasks - respond to a target tone by: (1) counting; (2) pressing a response button with the right index finger; or (3) pressing a response button with the left index finger. Although patients with schizophrenia had smaller and later P300 amplitudes than controls, they did not have smaller P300s over the left temporal scalp (T3) than over the right (T4). P300 recorded over the left (C3) and right (C4) motor cortices indicated sensitivity to responding hand, with greater negativity being associated with contralateral button pressing. Failure to find P300 asymmetry is not related to the presence or absence of a button pressing task, or the hand used for button pressing. Rather, P300 asymmetry may be related to structural neuroanatomical asymmetries.     

Response mode and P300 from auditory stimuli

The P300 component of the event-related brain potential (ERP) was elicited with a simple auditory discrimination task. Subjects were required to respond in three different ways to target stimuli across conditions: (1) silently counting the targets; (2) tapping their index finger every time a target was detected; or (3) pressing a button with their thumb when a target was presented. In addition, ERPs were recorded during each response mode while the subjects' eyes were either open or closed. P300 amplitude was larger for the counting compared to the tapping or button press tasks especially during the eyes closed condition. The peak latency of the P300 was longer when obtained from the counting compared to the tapping and button-press tasks for both eye conditions. Response mode also interacted with electrode site for peak latency. The results suggest that the P300 ERP component is sensitive to the nature of the subject's response during discrimination tasks.     

Cerebral Dynamics of SEPs to Non-Painful and Painful Cutaneous Electrical Stimulation of the Thenar and Hypothenar

Early, middle and late latency somatosensory evoked potentials (SEPs) elicited by cutaneous electrical stimulation (painful vs. non-painful) of right and left hands were recorded. The aims were to study (1) if lifelong use of dominant right hand would result in different SEP topographies compared to non-dominant left hand stimulation, (2) if painful and non-painful stimuli resulted in different SEP activation patterns for the different latency components and (3) if these results were consistent between two areas of the hand. Electrical stimuli were applied cutaneously above the thenar and hypothenar muscles of the left and right hand. A two-way repeated measures ANOVA was used to test the effects of laterality and intensity for a given peak amplitude and latency. Statistical results yielded no significant difference in peak amplitude for either thenar and hypothenar between the two hands. In contrast, a significant difference in amplitude was observed for 6 components for each stimulus location when the two intensities were compared. These components were found at early, middle and late latencies. No significant latency shift was observed between the two hands. Only the P30 component showed a significant latency shift for both locations with the painful condition having the shorter latency. Thus, life-long use of the dominant hand does not generate detectable changes in cortical evoked activity to sensory input from the skin above thenar and hypothenar muscles. Several SEP components across the time course (0-400 ms) showed increased amplitude when the stimulus was increased from non-painful to painful intensity.     

Inhibitory mechanisms in lateral geniculate nucleus of rat

1. An examination was made of the mechanisms responsible for the inhibition of synaptic transmission through the lateral geniculate nucleus (LGN) of the rat following a single shock to the optic nerve.2. In the rat anaesthetized with paraldehyde we found no evidence that optic nerve stimulation produced any presynaptic inhibition in LGN. In agreement with other workers it was found that repetitive stimulation of visual cortex produced effects attributable to presynaptic inhibition. However, this was of small magnitude in the conditions of our experiments.3. Stimulation of the optic nerve elicited an action potential in a P cell (principal cell) which was followed by a wave of hyperpolarization lasting about 150 msec (inhibitory post-synaptic potential, IPSP, wave).4. The IPSP wave was chloride-dependent and was associated with inhibition of the P cell discharge. Occasional rippling on the IPSP wave suggests that it was produced by the repetitive discharge of I cells (interneurones).5. These observations support the model proposed previously wherein P cells are inhibited by I cells which in turn are excited by axon collaterals of P cells. There is evidence for diffuse interconnexions between P cells and I cells.6. The observation that the extracellularly recorded wave of hyperpolarization (P-wave) is usually negative suggests that most of the inhibitory synapses are not on the soma of the P cell.     

Cutaneomotor integration in humans is somatotopically organized at various levels of the nervous system and is task dependent

Integration of tactile afferent signals with motor commands is crucial for the performance of purposeful movements such as during manipulation of an object in the hand. To study the somatotopic organization of sensorimotor integration we applied electrical peripheral conditioning stimuli to a digit located near (homotopic stimulation) or distant from (heterotopic stimulation) relaxed or isometrically contracted intrinsic hand muscles at variable time intervals prior to transcranial magnetic stimulation (TMS). Cutaneous stimulation has previously been shown to modulate the amplitude of the motor evoked potential (MEP) and to shorten the duration of the silent period (SP) evoked by TMS. In relaxed target muscles the time-dependent modulation of TMS-evoked motor responses by homotopic conditioning stimulation differed from modulation by heterotopic stimulation. Similar differences in the modulation pattern evoked by homotopic and heterotopic conditioning stimulation were observed for two distinct target muscles of the hand (abductor digiti minimi, abductor pollicis brevis muscle). Differences in modulation were maximal when the conditioning stimulation was applied 25–30 ms and 150–200 ms prior to TMS. Comparison of the modulation of the amplitudes of MEPs evoked by transcranial electrical stimulation (TES) and the modulation of those evoked by TMS suggests that differences between homotopic and heterotopic stimulation originate subcortically at 25- to 30-ms and, at least partially, cortically at 150- to 200-ms interstimulus intervals. In isometrically contracted intrinsic hand muscles the degree to which the SP was shortened reflected the location and the timing of the conditioning stimulus. Shortening was maximal when the conditioning stimulus was applied nearest to the contracted target muscle and 20 ms prior to the test stimulus. In contrast to the SP duration, the MEP size in voluntarily contracted target muscles was unaffected by the location of the conditioning stimulus. The somatotopic gradient of SP shortening was abolished when the two target muscles were simultaneously activated isometrically. Together, our findings suggest that somatotopy of input-output relationships is implemented at both a spinal and a cortical level in the human central nervous system and may also depend on the motor task involved. Received: 25 August 1998 / Accepted: 11 June 1999     

肝硬化失代偿期病人体感诱发电位观察

目的 :探讨肝硬化失代偿期病人的神经功能状态。方法 :对 30例肝硬化失代偿期病人进行体感诱发电位 (SEP)检查 ,刺激部位均为右腕正中神经。结果 :肝硬化失代偿期病人的SEP有着不同程度的改变 ,其中P15、N2 0 、P2 5、N3 5的潜伏期延长和N13 -P15的波间期延长分别占本组异常数的 85 %、40 %、35 %、2 5 %和 2 0 %。这些值与正常人组相比较 ,其两组间差异均有极显著性意义 (P <0 0 1)。结论 :SEP可为研究亚临床肝性脑病提供电生理学的客观依据。     

Hemispheric Asymmetry for Word Perception: Behavioral and ERP Evidence

Reaction times (RTs) to words or patterns presented in the left or right visual fields and averaged Event-Related Potentials (ERPs) evoked by the same stimuli presented foveally were measured separately. In both experiments, an oddball paradigm known to elicit the P3 component was used. Twenty-four subjects (12 males) were tested in each experiment. In the electrophysiological study EEG was measured differentially from five different scalp sites, each referred to linked ear lobes. There were two frontal and two parietal lateralized electrodes, and a fifth which was located at the vertex (C_z). The RTs to words were significantly delayed relative to the RTs to patterns. Furthermore, the responses were significantly shorter in the right visual field when the target was a word, yet only slightly shorter in the left visual field when the target was a nonsense pattern. The same pattern of results was found with the evoked potentials: A positive wave evoked by the target stimulus was measured at vertex with mean latency of 511.3 msec in the verbal task, and 464.4 msec in the nonverbal task. At the lateralized locations, a significant Task by Hemisphere interaction was found. When the target was a word the base to peak P3 amplitudes were higher over the left than over the right hemisphere. A reverse trend was found with nonverbal targets. The base to peak P3 amplitudes were slightly (but not significantly) higher over the right than over the left hemisphere.     

Characteristics of No-go-P300 component during somatosensory Go/No-go paradigms

The present study investigated one of the characteristics of No-go-related brain activity during somatosensory Go/No-go paradigms, by manipulating the stimulus site and response hand. Somatosensory event-related potentials (ERPs) were recorded in ten right-handed subjects. Electrical stimulation was delivered to the second and fifth digit of one hand, and the subjects had to respond to a Go stimulus by pushing a button with the thumb contralateral to the stimulated side as quickly as possible. We focused on the peak amplitude and latency of Som-Go-P300 (P300 evoked by somatosensory Go stimuli) and Som-No-go-P300 (P300 evoked by somatosensory No-go stimuli) components. The amplitude of Som-No-go-P300, which is very similar to No-go-P300 components following visual and auditory stimulation, was significantly larger than that of Som-Go-P300 at fronto-central electrodes, indicating ‘anteriorization’ of the No-go-P300. The amplitude of Som-No-go-P300 was significantly larger in right than left hemispheres during right hand response conditions, but this difference was not found under left hand conditions. In addition, the difference in amplitude between Som-Go- and Som-No-go-P300, which is frequently described as ‘the Go/No-go effect’ on P300, was significant in the left hemisphere under right hand response conditions, whereas a significant effect was found in both the left and the right hemispheres under left hand response conditions. Our findings suggested that the anteriorization of No-go-P300 was independent of stimulus modalities such as visual, auditory, and somatosensory, and the amplitude of No-go-P300 and Go/No-go effects on P300 was affected by the response hand.