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以适宜参数的电流作用于神经中枢而研究其效果,是一项常用的电生理学方法。在直接电刺激中枢神经系统时,单向波容易产生极化作用,损伤神经组织,妨碍实验研究的正常进行,而双向波则可避免极化损伤作用,因此,目前国外关于中枢神经系统电刺激的实验研究一般已不再使用单向波,而广泛采用双向方波电刺激。本仪器可做为神经生理学及其有关学科的研究工具。  相似文献   
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汉字识别的跨感觉通路ERP注意成分研究   总被引:1,自引:0,他引:1       下载免费PDF全文
采用提高非注意纯度的“跨通路延迟反应”实验模式 ,观察汉字形音判断的跨通路事件相关电位 (ERP) ,研究N1和早期注意成分 (Nd1 ) .被试为 1 5名青年正常人 .结果发现 ,N1在头皮上的分布存在明显的通路间差异 :既与非语言实验结果不同 ,也与英语实验结果不同 ,可能反映出汉字加工的脑机制特征 .注意加工部位随语言 /非语言、听觉 /视觉通路、偏差刺激 /标准刺激 3种条件的不同而变化 ,具有可塑性 .早期注意效应发生在刺激本身诱发的外源性成分之前 ,支持注意的早期选择学说 .根据N1与Nd1的关系 ,支持注意使N1增大者不是外源性成分 ,而是重叠于外源性成分中的内源性成分的观点  相似文献   
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跨通路注意的失匹配负波研究   总被引:1,自引:0,他引:1       下载免费PDF全文
采用“跨通路延迟反应”实验模式 ,提高了非注意纯度 ,排除了偏差刺激中的目标任务因素 ,以 1 2名青年正常人为被试者 ,研究注意与非注意条件下的ERPs.实验分为 2项 :( 1 )注意视觉通路 ,忽视听觉通路 ;( 2 )注意听觉通路 ,忽视视觉通路 .主要分析偏差刺激ERP减去标准刺激ERP所得之偏差成分 .结果发现视听通路在注意条件下均能产生MMN ,N2b和P3,在非注意时主要产生MMN .听觉MMN与视觉MMN具有如下共同特征 :注意时视听最大MMN波幅分布于它们的初级感觉投射区 ,而在非注意条件下视听最大MMN波幅均分布于额中央部 .视觉MMN与听觉MMN波幅无显著性差异 .MMN波幅及其头皮分布不受注意影响 ,提示MMN波幅是反映自动加工的重要ERP指标 ;但视听觉MMN潜伏期皆受注意影响 ,表明MMN不仅仅反映自动加工 ,尚与控制加工有关  相似文献   
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Event-related potentials (ERPs) were measured in 15 normal young subjects (18—22 years old) using the "cross-modal and delayed response" paradigm, which is able to improve inattention purity. The stimuli consisted of written and spoken single Chinese characters. The presentation probability of standard stimuli was 82.5% and that of deviant stimuli was 17.5%. The attention components were obtained by subtracting the ERPs of inattention condition from those of attention condition. The results of the N1 scalp distribution demonstrated a cross-modal difference. This result is in contrast to studies with non-verbal as well as with English verbal stimuli. This probably reflected the brain mechanism feature of Chinese language processing. The processing location of attention was varied along with verbal/non-verbal stimuli, auditory/visual modalities and standard/deviant stimuli, and thus it has plasticity. The early attention effects occurred before the exogenous components, and thus provided evidence support  相似文献   
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Mismatch negativity of ERP in cross-modal attention   总被引:1,自引:0,他引:1  
Event-related potentials were measured in 12 healthy youth subjects aged 19-22 using the paradigm "cross-modal and delayed response" which is able to improve unattended purity and to avoid the effect of task target on the deviant components of ERP. The experiment included two conditions: (i) Attend visual modality, ignore auditory modality; (ii) attend auditory modality, ignore visual modality. The stimuli under the two conditions were the same. The difference wave was obtained by subtracting ERPs of the standard stimuli from that of the deviant stim-uli. The present results showed that mismatch negativity (MMN), N2b and P3 components can be produced in the auditory and visual modalities under attention condition. However, only MMN was observed in the two modalities un-der inattention condition. Auditory and visual MMN have some features in common: their largest MMN wave peaks were distributed respectively over their primary sensory projection areas of the scalp under attention condition, but over front  相似文献   
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