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排序方式: 共有681条查询结果,搜索用时 15 毫秒
1.
为探讨药物改善低氧条件下人体做功效率的途径,我们在喀喇昆仑山海拔3 700m进行了三普红景天及乙酰唑胺对人体PWC170效应的研究,并以睡眠剥夺加重受试者的疲劳程度进行比较. 相似文献
2.
Philip M. Zeman Bernie C. Till Nigel J. Livingston James W. Tanaka Peter F. Driessen 《Clinical neurophysiology》2007,118(12):2591-2604
OBJECTIVE: To evaluate the effectiveness of a new method of using Independent Component Analysis (ICA) and k-means clustering to increase the signal-to-noise ratio of Event-Related Potential (ERP) measurements while permitting standard statistical comparisons to be made despite the inter-subject variations characteristic of ICA. METHODS: Per-subject ICA results were used to create a channel pool, with unequal weights, that could be applied consistently across subjects. Signals derived from this and other pooling schemes, and from unpooled electrodes, were subjected to identical statistical analysis of the N170 own-face effect in a Joe/No Joe face recognition paradigm wherein participants monitored for a target face (Joe) presented amongst other unfamiliar faces and their own face. Results between the Joe, unfamiliar face and own face conditions were compared using Cohen's d statistic (square root of signal-to-noise ratio) to measure effect size. RESULTS: When the own-face condition was compared to the Joe and unfamiliar-face conditions, the channel map method increased effect size by a factor ranging from 1.2 to 2.2. These results stand in contrast to previous findings, where conventional pooling schemes failed to reveal an N170 effect to the own-face stimulus (Tanaka JW, Curran T, Porterfield A, Collins D. The activation of pre-existing and acquired face representations: the N250 ERP as an index of face familiarity. J Cogn Neurosci 2006;18:1488-97). Consistent with conventional pooling schemes, the channel map approach showed no reliable differences between the Joe and Unfamiliar face conditions, yielding a decrease in effect size ranging from 0.13 to 0.75. CONCLUSIONS: By increasing the signal-to-noise ratio in the measured waveforms, the channel pool method demonstrated an enhanced sensitivity to the neurophysiological response to own-face relative to other faces. SIGNIFICANCE: By overcoming the characteristic inter-subject variations of ICA, this work allows classic ERP analysis methods to exploit the improved signal-to-noise ratio obtainable with ICA. 相似文献
3.
Generators of visual evoked potentials for faces and eyes in the human brain as determined by dipole localization 总被引:4,自引:0,他引:4
Human visual evoked potentials were recorded during presentation of photos of human and animal faces and various face features. Negative waves with approximate peak latencies of 165 msec (N170) were bilaterally recorded from the occipito-temporal regions. Mean peak latencies of the N170 were shorter for faces than eyes only. Analyses of amplitudes of evoked potentials indicated that the N170 elicited by faces reflected activity of a specific neural system which was insensitive to detailed differences among individual faces regardless of species, and consequently suggest that this system might function to detect existence of faces in general. On the other hand, the mean amplitude of the N170 elicited by human eyes was significantly larger than those by animal eyes. These differences in response latencies and amplitudes of the N170 suggest existence of at least 2 different visual evoked potentials with similar latencies (i.e., N170) which are sensitive to faces in general and human eyes, respectively. Dipole source localization analysis indicated that dipoles for the N170 elicited by eyes were located in the posterior inferior temporal gyrus, and those for faces, located initially in the same region, but moved toward the fusiform and lingual gyri at the late phase of the N170. The results indicated that information processing of faces and eyes separated at least as early as the latency of the N170 at the posterior inferior temporal gyrus as well as the fusiform and lingual gyri, and might provide neurophysiological and anatomical bases to an initial structural encoding stage of human faces. 相似文献
4.
Hereditary spastic paraplegia (HSP) is a heterogeneous group of inherited neurodegenerative disease characterized by progressive lower limb spasticity. Recent studies revealed that biallelic variants in RNF170 gene cause autosomal recessive complicated HSP with infancy onset. Here, we report an adolescent-onset HSP patient from a consanguineous Chinese family, with lower extremity stiffness, spastic gait, and unstable straight-line walking as the main manifestations. Whole-exome sequencing identifies a novel RNF170 mutation c.190C>T (p.R64*), which co-segregates with the disease in this pedigree. Functional analysis, including quantitative real-time PCR (RT-qPCR) and Western blot, indicates that both the mRNA and protein levels of mutant RNF170 are significantly reduced, which confirms the loss-of-function mechanism. Our study expands the spectrum of RNF170-associated HSP, while the RNF170 protein-involved degradation of the inositol 1,4,5-trisphosphate receptor in neurodegenerative motor neuron disorders deserves further investigation. 相似文献
5.
为证实肿瘤多项耐药基因( M D R1) 产物 P G P170 与膀胱癌化疗失败及复发的关系,利用免疫组化方法对72例膀胱癌进行了研究。发现膀胱癌术后丝裂霉素膀胱灌注化疗失败者的 P G P170 阳性率及强阳性率均明显高于初发膀胱癌,并且高分级肿瘤的 P G P170 阳性及强阳性表达均高于低分级肿瘤。通过本实验可以认为膀胱癌化疗效果如何与膀胱癌组织中 M D R1 产物的量有关。 相似文献
6.
目的 检测多药耐药基因蛋白P 糖蛋白 (P GP170 )和肺耐药蛋白 (LRP)与抗核抗体Ki 6 7在甲状腺乳头状癌中的表达及临床意义。方法 采用免疫组化SP法检测P GP170、LRP、Ki 6 7在 6 4例甲状腺乳头状癌和 2 0例甲状腺腺瘤中的表达。结果 3种抗体在甲状腺乳头状癌中均呈高表达 ,在甲状腺腺瘤中呈低表达。与甲状腺腺瘤相比有显著性差异 (P <0 .0 1)。P GP170、LRP、Ki 6 7三者呈显著相关性 (LRP与Ki 6 7r =0 .4 2 ,LRP与P GP170r =0 .4 2 ,Ki 6 7与P GP170r =0 .6 5 ,P <0 .0 1)。结论甲状腺乳头状癌标记指数高、耐药性强、化疗敏感性低。在化疗中同时给予耐药抑制剂 ,可以提高化疗敏感性和化疗效果。 相似文献
7.
目的:探讨孤独症儿童与普通儿童在面孔识别事件相关电位(ERP)的差异。方法:以中性表情的面孔以及物件照片为刺激材料,以儿童喜欢物件的照片作为靶刺激,采用32通道ERP仪,分别记录20名孤独症儿童与22名普通儿童的ERP,比较两类儿童在不同刺激下N170电位的前体(Pre—cursorN170,PrN170)成分。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长(P〈0.05),正确率无差别(P〉0.05);两组儿童在面孔刺激呈现后约220ms颞枕叶导联发现PrN170,两组问对于不同类型的图片刺激,PrN170电位波幅与潜伏期均未见差异(P〉0.05)。结论:孤独症儿童的面孔结构编码过程无显著异常。 相似文献
8.
Agustín Ibá?ez Jaume Aguado Sandra Baez David Huepe Vladimir Lopez Rodrigo Ortega Mariano Sigman Ezequiel Mikulan Alicia Lischinsky Fernando Torrente Marcelo Cetkovich Teresa Torralva Tristan Bekinschtein Facundo Manes 《Social cognitive and affective neuroscience》2014,9(7):939-950
It is commonly assumed that early emotional signals provide relevant information for social cognition tasks. The goal of this study was to test the association between (a) cortical markers of face emotional processing and (b) social-cognitive measures, and also to build a model which can predict this association (a and b) in healthy volunteers as well as in different groups of psychiatric patients. Thus, we investigated the early cortical processing of emotional stimuli (N170, using a face and word valence task) and their relationship with the social-cognitive profiles (SCPs, indexed by measures of theory of mind, fluid intelligence, speed processing and executive functions). Group comparisons and individual differences were assessed among schizophrenia (SCZ) patients and their relatives, individuals with attention deficit hyperactivity disorder (ADHD), individuals with euthymic bipolar disorder (BD) and healthy participants (educational level, handedness, age and gender matched). Our results provide evidence of emotional N170 impairments in the affected groups (SCZ and relatives, ADHD and BD) as well as subtle group differences. Importantly, cortical processing of emotional stimuli predicted the SCP, as evidenced by a structural equation model analysis. This is the first study to report an association model of brain markers of emotional processing and SCP. 相似文献
9.
Isometric handgrip (IHG) imposes an acutely increased afterload on the left ventricle. Utilizing systolic time intervals, we studied various responses to IHG, measured as changes from resting values with near-maximum IHG, in old normal (ON) subjects, young normal (YN) subjects, and old patients with hypertensive heart disease (HHD) and patients with coronary artery disease (CAD). There were no differences in responses to IHG between ON and patients with HHD or patients with CAD. However, there were clear differences between the responses of ON and YN subjects. Increase in heart rate (HR) was much more prominent in YN (ON vs. YN = +11.6 +/- 2.6 vs. +15.6 +/- 5.7 beats per minute p less than 0.001). Pre-ejection period (PEP) end isovolumic contraction time (IVCT) increased in ON but decreased in YN (PEP + 6.2 +/- 1.7 vs. -11.0 +/- 3.7 msec., p less than 0.001; IVCT +8.1 +/- 2.2 vs. -13.8 +/- 3.4 msec., p less than 0.001. Shortening of LVET was much more marked in YN (-6.5 +/- 4.1 VS. -63.3 +/- 9.9 msec. p less than 0.001), but this was entirely due to the HR differences since there was no difference in ejection time index (+ 5.1 +/- 3.4 vs. -0.4 +/- 7.3 msec. p greater than 0.5). IHG produced no significant differences between ON and YN in the timing of the "mitral" component of the first heart sound (q-Im), in the ratio PEP/LVET, or in pulse transmission time (PTT). By contrast, resting control PTT was markedly short in ON, especially those with CAD. Resting PTT in ON was 27.1 +/- 2.6 msec.; in YN 43.7 +/- 1.4 msec.; in CAD patients 20.7 +/- 1.3 msec. We conclude that even near-maximal IHG does not seem to be an adequate noninvasive screening test for cardiovascular disease in that age alone seems to have the most significant influence on the responses. 相似文献
10.