面孔识别特异性脑机制的ERP研究

目的 研究面孔识别加工成分N170是否真正反映面孔识别加工的特异性及其是否是衡量面孔结构编码的特异指标；另外尚运用偶极子定位法论证面孔识别加工特异脑区、面孔识别加工是否具有右半球优势等问题。方法 16名被试学习和再认面孔照片，记录其脑电。结果 实验结果表明，仅半数被试出现N170；认知任务显著影响N170波幅。结论 N170不仅反映面孔的结构编码还反映视觉直接加工等其他加工单元，是否反映面孔识别加工特异性还值得进一步研究；面孔识别加工时两半球的优势在加工速度与加工强度两个维度上各占优势，并非单纯的右脑优势，提供了支持半球间两维关系观点的新电生理学证据；面孔识别加工的脑区不仅限于梭状回，顶叶后部偏右的皮层下结构应该也是一个面孔识别加工脑区。     

网络成瘾患者早期面孔加工N170的研究

目的 研究网络成瘾患者面孔早期加工的脑机制.方法 被试者分为正常对照组18～21岁和网络成瘾组17～22岁,各10名,均为右利手.刺激包括3种卡通面孔(中性、微笑、愤怒)和3种非面孔,要求被试者进行面孔识别任务,同时记录32导脑电.结果 1)对照组产生了明显的颞-枕区分布的面孔特异性成分Nd170(面孔的N170减去非面孔的N170);2)与对照组相比,网络成瘾组Nd170表现为明显的枕区分布,且幅值显著增强、潜伏期明显提前.结论 网络成瘾患者可能具有与正常被试者不同的面孔早期加工机制.     

面孔内外特征对东西方面孔识别影响的ERP研究

目的 研究有无外部特征的东西方面孔在认知识别上的脑机制。方法 16名被试者辨别东西方人面孔性别，记录其脑电。结果 无论东西方面孔，无外部特征比有外部特征的面孔的P170波幅均增大，而N240波幅明显减小；西方面孔无外部特征与有外部特征的面孔产生的P170和N240之间的差异较东方面孔的小。上述变化在头皮前部更为显著。结论 在识别东西方面孔的过程中，均需要更多的资源分配于无外部特征面孔；有外部特征的面孔在加工机制上明显不同于没有外部特征的面孔，这一点还表现为被试者正确率的增加和反应时的加快；另外，西方面孔产生的差异波较东方面孔的小为弄族面孔在识别上容易混淆提供了电生理证据，而且也为弄族效应理论中的种族特征没有包含在面孔外部特征上提供了电生理证据。     

EPP:一个与表情特征加工相关的ERPs晚期正成分

目的 研究与表情特征加工相关的事件相关脑电位（event-related potentials，ERPs）成分。方法 被试者为12名（7男5女）右利手健康大学生。刺激包括3种卡通面孔（中性、微笑、愤怒）和3种非面孔。要求被试者进行面孔识别（face recognition，FR）和面孔表情分类（facial expression classification，FEC）2种作业。记录32导脑电。结果 1）与FR任务相比，FEC任务产生明显的P580成分；2）FEC的ERP与FR的ERP的差异波形，表现出一个非常明显的中央一顶区分布的正差异（450～850ms），命名为表性加工正成分（expression processing positivity，EPP）；3）EPP的峰值潜伏期表现出明显的表情特征主效应，以愤怒面孔EPP的潜伏期最短，微笑面孔EPP的潜伏期最长。结论 EPP可能反映了表情特征的晚期加工。     

编码非相关词对是否具有半球对称性?一项近红外光学成像的研究

目的本研究采用近红外光学成像技术（fNIRS）,探讨双侧前额叶在非相关词对的语义编码过程中的作用。方法48名被试者分别在深、浅加工2种实验条件下对非相关词对进行编码,光学成像器即时记录在前额叶皮层,波长为760nm和850nm的漫射光强变化,以此推测相应脑组织的血容量变化。结果与浅加工相比,在深加工条件下,双侧前额叶中与背外侧前额叶相对应区域的血容量变化都较为明显,尤其是左侧前额叶。本研究结果并不完全支持HERA模型,但与其它相关的脑成像研究结果相似。结论材料的特异性是影响记忆编码中半球一侧化的重要因素,当需要对刺激间的联系进行加工时,右侧前额叶也会参与记忆的编码过程。本研究还提示fNIRS技术可用于记忆等脑高级认知功能的研究。     

情绪刺激转换对注意转换代价影响的ERP研究

目的 用事件相关脑电位(ERPs)来研究情绪刺激转换对Switch Cost的影响特点。方法 被试者为14名(7男7女)右利手健康大学生。情绪刺激包括表情卡通面孔和中性卡通面孔。采用Garavan的计数双任务范式,要求被试者对刺激序列中表情面孔和中性面孔分别进行计数。记录64导脑电。结果 1)刺激转换与非转换条件下主要区别表现在N2波幅增大及P3波幅下降;2)情绪刺激转换的ERP与无刺激转换的ERP相减所得到的差异波产生了明显的Nd370,主要分布在顶区;3)表情面孔转换为中性面孔的Nd370波幅比中性面孔转换为表情面孔的Nd370要小。结论 顶区分布的Nd370可能是情绪刺激转换的特征性指标,为Switch Cost的理论提供了客观依据。     

用近红外功能成像技术研究语义和知觉编码过程中左前额叶的活动

目的用近红外光学功能成像技术研究语义与知觉编码过程中的左前额叶活动.方法实时记录22名青年被试者(男女各半)在语义和知觉加工过程中760 nm和850 nm两个波长近红外连续光透过额骨和左前额皮层后的漫射光强变化,并以此表征该皮层区血容(CBV)和血氧的变化.语义加工要求被试者用两个非相关的汉字词对组成一个有意义的句子;知觉加工则要求被试者判断两个词是否具有相同的结构组合以及两个词对中左右结构的差别. 结果结果显示,与知觉加工相比,语义加工时左下前额叶活动增多.该区域大致对应布德曼45、47区的一部分. 结论成功地利用近红外功能成像技术观测了语义与知觉编码过程中的左前额叶活动,获得了与fMRI和断层成象技术(PET)研究相近的结果,进一步证实了左前额叶在语义加工中的作用.     

视觉注意范围的调控机制

目的：使用固定位置的位置性注意范围提示，研究注意范围的脑内时程的动态变化。方法：被试者为12名健康右利手青年人，视觉刺激序列为：背景－提示－靶刺激。提示物为一个圆，有3种大小，其圆心均在屏幕中点。要求被试在提示范围内寻找靶刺激并判断其朝向。同时记录反应时和128导脑电（EEG）数据。结果：随着注意范围的扩大，对同等位置靶刺激的反应时缩短；靶刺激诱发ERP的P1、N1不受提示范围大小的影响，而其后部P2波幅与注意范围显著相关，前部N2的波幅随注意范围的扩大而增大。结论：1）视觉注意诱发的P1、N1成分，主要与空间方位信息的加工相关；2）提示物诱发的P2、N2成分与注意范围相关，其机制与注意方位的增益机制类似；3）在视觉信息加工过程中，注意方位信息要早于注意范围信息被加工，支持这两者间串行加工的观点。     

等概率听觉选择反应中非靶ERPs的N2效应

目的研究等概率听觉选择反应任务中非靶ERPs的N2效应是否存在及其特点。方法被试者为1 6名右利手健康男性青年 ( 2 3 .2± 2 .1岁 )。刺激为听觉输入的一位数字信号序列 ( 2～ 7) ,要求被试者对靶数字进行拨开关反应 ,对非靶数字不作反应。记录 9导脑电。结果 1 )非靶ERPs产生了明显的N2 80 (N2效应 ) ,额区最为突出 ;2 )非靶ERPs中P3的潜伏期明显长于、峰值显著小于靶ERPs,且头皮分布比靶ERPs(顶区优势 )更趋于中央脑区分布。结论听觉通道亦存在非靶N2效应 ,且不能简单理解为是对靶刺激反应的抑制 ,而更可能反映了工作记忆中模式的重调过程 ,而这一过程的完成可能比靶数字出现时的反应更为复杂 ,且主要发生在额区     

模拟飞机降落过程中的眼动和认知研究

目的：对眼睛运动规律和大脑认知进行实验分析，研究被试者的注意力分配特点。方法：通过模拟飞机的降落过程，用眼动测量设备采集眼动数据并对眼动数据进行分析。结果：实验得到的眼动数据表明，被试者的注意力主要集中在飞机平显上的3个目标兴趣区域，被试者主要在目标兴趣区域之间进行视觉活动、分配和转换注意力。结论：被试者主要利用由上到下（top-down）的认知机制驱动眼动，分配注意力。眼动的结果使被试者获取了飞机飞行的情景意识。     

Lateralization of cortical function in swallowing: a functional MR imaging study.

BACKGROUND AND PURPOSE: While functional MR imaging and other techniques have contributed to our knowledge of functional brain localization, these methods have not been extensively applied to the complex and incompletely understood task of swallowing. We used functional MR imaging to investigate motor cortex activity during swallowing in healthy human adults. METHODS: Eight subjects were imaged on a 1.5-T MR system using blood oxygen level-dependent contrast mechanisms. Subjects performed three swallowing tasks and a finger-tapping task. Areas of activation in the cortex and subcortical areas were tabulated, and a laterality index, defined as LI = [sigmas left - sigmas right]/[sigmas left + sigmas right] x 100, was computed for the three tasks. RESULTS: Activation was observed in the primary motor and sensory cortices, motor processing and association areas, and subcortical sites. This activity was dominant for one hemisphere with left hemispheric dominance more prevalent among the subjects. Right hemispheric dominance, however, showed stronger lateralization than the left hemisphere. CONCLUSION: Our data indicate that specific sites in the motor cortex and other cortical and subcortical areas are activated with swallowing tasks and that hemispheric dominance is a feature of swallowing under these conditions. In addition, we demonstrate the utility of functional MR imaging in the study of the cortical representation of swallowing and suggest a role for functional MR imaging in the diagnosis of dysphagia of cerebral origin.     

Cerebral atrophy and crossed cerebellar atrophy following acute subdural hematoma in infant

Crossed cerebellar atrophy (CCA) on imaging study reflects secondary degeneration of the cerebellar hemisphere caused by neuronal disconnection with the contralateral cerebral hemisphere. We report an 11-month-old child with traumatic left acute subdural hematoma, who showed crossed cerebellar atrophy on MR images. Eighteen months after the trauma, MR images showed brain atrophy not only in the left cerebral hemisphere but also in the right cerebellar hemisphere. The cerebellar atrophy was prominent in the lateral part. This finding is consistent with CCA and may support neuronal interactions between the cerebral hemisphere and the lateral part of the contralateral cerebellar hemisphere.     

Visual evoked potentials, reaction times and eye dominance in cricketers

AIM: Few studies have examined the physiology of cricket, including the difference in ability between batsmen to make controlled contact with a ball bowled at high speed. METHODS: We therefore measured visual evoked potentials and choice reaction times with dominant eyes, non-dominant eyes, and both eyes together, in 15 elite batsmen and 10 elite bowlers (aged 20.9 SD 1.9 years) and 9 control subjects (aged 20.2 SD 1.5 years). The latency and amplitude of waves N70, P100 and N145 were determined for each visual evoked potential (VEP). In addition interpeak latencies and peak to peak amplitudes were measured. The subjects also completed a choice reaction test to a visual stimulus. RESULTS: We found that cricketers were not more likely to have crossed dominance (dominant eye contralateral to dominant hand) than controls. Cricketers had a faster latency for VEP wave N70 than controls (p=0.03). However reaction time was not different between cricketers and the control group. Across all subjects, in comparison to monocular testing, binocular testing led to a faster choice reaction time (p=0.02) and larger amplitudes of VEP wave N70 (p=0.01). CONCLUSION: Visual processing during the first 100(-1)50 ms of the balls flight together with binocular vision facilitates retinal activation in talented cricketers.     

Ipsilateral hemisphere activation during motor and sensory tasks.

PURPOSETo compare activation of the ipsilateral cerebral hemisphere during tactile sensory and motor tasks involving the right and left hands.METHODSEight volunteers had functional MR imaging to measure the extent of cerebral hemisphere activation during a motor task and sensory task involving each hand. Hemispheric indexes (left hemisphere activation minus right hemisphere activation)/(left hemisphere activation plus right hemisphere activation) were computed for each hand and each task. The indexes for two tasks and the two hands were compared.RESULTSThe left-hand motor tasks activated the ipsilateral hemisphere in right handers significantly more than did the right-hand tasks. Motor tasks produced a greater activation of the ipsilateral hemisphere than did the sensory tasks. No significant differences were found between the hemispheric indexes for the right-hand and left-hand sensory tasks.CONCLUSIONThis study confirms findings of a previous study, showing that the left hemisphere is active in left-hand motor tasks. Activation of the ipsilateral hemisphere is significantly less pronounced during sensory tasks than during motor tasks.     

听觉事件相关电位(ERPs)早期和晚期成份的任务负荷效应

目的 比较不同任务负荷的听觉事件相关电位（ERPs,event-related potentials)，以探讨听觉ERPs各种成份的任务负荷效应。方法 被试者为12名右利手正常在校大学生（20－23岁）。要求被试者对4个方位的声音信号进行难度负荷不同的3种作业任务：全反应（AR）、方位区分反应（DR）、音调选择方位式区分反应（SR）。对－t和方差分析统计3种任务的听觉ERPs成份。结果1）SR反应时最长，DR次之，AR最短；2）早期成份的任务负荷效应：P1波幅随负荷的增加进行性增强；AR－ERPs的NI峰值相近，均高于SR（T）－ERPs；DR－ERPs与SR（T）－ERPs中前脑区的P2波幅无明显差异，均显著低于AR－ERPs，P2的潜伏期随负荷的增加明显缩短；3）晚期成分的任务负荷效应；随任务负荷的增加，N2（N2a/N2b),P3和SW波幅明显增强。结论 听觉ERPs早期成份和晚期成份均有明显的任务负荷效应，晚期成份的任务负荷效应可能与早期的警觉激活程度相关联。     

纯音听觉优势半球--fMRI和脑磁图联合研究

目的 利用血氧水平依赖功能磁共振成像（BOLD-fMRI）和脑磁图（MEG）观察正常人在纯音刺激时听觉中枢的兴奋情况及两侧半球的差异。资料与方法 BOLD-fMRI研究对象为30名正常听力志愿者。BOLD-fMRI采用组块设计。声音刺激用140曲1kHz纯音，持续时间500in8，刺激间隔18，刺激施加频率1Hz。MEG检查共有10名正常受试者，采用90dB1kHz纯音刺激，持续时间8ms，刺激间期1s。用等电流偶极（ECD）描述皮质兴奋并将其与自身MRI图像叠加。结果 在BOLD-fMRI研究中，纯音刺激激活两侧听觉中枢和其周围邻近脑区，右侧半球听觉中枢的激活强度明显大于左侧。MEG检查中纯音刺激诱发的主要磁反应波为M100，M100 ECD位于初级听觉中枢预横回。右侧半球M100 ECD比左侧半球偏前、潜伏期短、强度高。结论 纯音刺激激活听觉中枢和周围脑区，右侧半球为纯音刺激时听觉的优势半球。     

Supplementary motor area activation in patients with frontal lobe tumors and arteriovenous malformations

BACKGROUND AND PURPOSE: Some patients who undergo surgical resection of portions of the supplementary motor area (SMA) have severe postoperative motor and language deficits, whereas others have no deficits. We tested the hypothesis that in some patients with lesions affecting the SMA, the contralateral SMA exhibits some of the activation normally associated with the ipsilateral SMA. METHODS: Functional MR imaging studies in seven healthy volunteers and 19 patients with frontal lobe tumors or arteriovenous malformations were reviewed retrospectively. The hemisphere in which the SMA activation predominated was tabulated for right and left motor tasks. The relative hemispheric dominance in the SMA for the right and left motor tasks was compared in the healthy and patient groups and with the location of the lesion in the patient group. RESULTS: None of the control subjects performing a right hand motor task activated predominantly the right SMA. Fifty percent of the patients with lesions overlapping the left SMA performing the right motor task activated predominantly the right SMA. Fifty-seven percent of control subjects performing the left hand motor task activated the left SMA predominantly. One hundred percent of patients with lesions overlapping the right frontal SMA performing the left motor task activated the left SMA predominantly. Differences between patients and controls were statistically significant. CONCLUSION: A lesion that contacts or overlaps the SMA is associated with an increased functional MR imaging response within the contralateral SMA.     

The influence of electrocortical biofeedback on performance in pre-elite archers

The purpose of the present research was to determine whether EEG biofeedback training could improve archery performance as well as self-reported measures of concentration and self-confidence. Experienced pre-elite male (N = 16) and female (N = 8) archers were randomly assigned to one of three treatment conditions: (a) correct feedback (i.e., greater left hemisphere low frequency activity), (b) incorrect feedback (i.e., greater right hemisphere low frequency activity), and (c) no feedback control. The pretest and posttest consisted of 27 shots, with EEG data collected for the left and right temporal hemispheres (T3, T4). Feedback subjects were then given EEG biofeedback, while control subjects rested for 30 min. Analyses indicated that only the performance measure was significant. The correct feedback group significantly improved performance, while the incorrect feedback group showed a significant performance decrement from pre- to posttest (Ps less than 0.05). The control group showed no significant pre-post differences in performance. EEG analyses showed differences that were consistent with the training given to the incorrect, but not the correct, feedback group. Overall, the results provide some support for the use of known relationships between EEG and performance as an effective means of providing biofeedback to affect the performance of pre-elite archers.