共查询到20条相似文献,搜索用时 9 毫秒
1.
I. N. Konareva 《Neurophysiology》2005,37(5-6):388-395
We studied changes in the frequency pattern of EEG related to a single session of biological feedback by the EEG characteristics
(neurofeedback, NFB) directed toward an increase in the ratio of α/θ spectral powers (SPs) (an experimental group; 30 subjects)
and to a session of the supposedly indifferent acoustic influence (listening to a musical background; 30 persons). A standard
technique of EEG recording was used; the loudness of white noise overlapping the musical background served as an NFB signal.
EEG was recorded from the C3 and C4 leads. Within the examined experimental group, an NFB session elicited a trend toward
statistically insignificant decreases in the SPs of δ, α, and β rhythms and increases in the SPs of θ and γ EEG components.
Listening to a supposedly neutral musical background by the control group, with no attempts at self-control of the SPs of
EEG rhythms, was followed by rather clear unidirectional (partially significant) decreases in the SPs of θ, α, β, and γ components;
the δ activity in the left hemisphere decreased, while in the right hemisphere it increased. In general, results of the single
NFB session were characterized by a high interindividual variability, which can be related mostly to the specificities of
psychophysiological characteristics of the personality of the tested subject.
Neirofiziologiya/Neurophysiology, Vol. 37, Nos. 5/6, pp. 443–451, September–December, 2005. 相似文献
2.
We studied changes in the amplitudes of event-related EEG potentials (ERPs) and power spectra of background EEG in the course
of a series of EEG-feedback sessions directed toward an increase in the ratio of powers of the α vs θ rhythms. The examined group included 70 volunteers divided into an experimental group (n = 37) and a control group (n = 33). The intensity of acoustic white noise overlapping the musical background served as a feedback signal; it became lower
with increase in the above ratio, while in the control group it remained constant. The EEG potentials were recorded from C3
and C4 leads. The ERPs were recorded within a paradigm of measuring time intervals. Within a series of EEG-feedback sessions,
the α/θ ratio decreased somewhat both in the control and experimental groups, but in subjects of the latter group this decrease
was less significant, and the mean intragroup index became significantly greater than the respective value in the control
group after the end of the third session. The EEG-feedback sessions also resulted in significant increases in the amplitudes
of early components of the readiness potential in both hemispheres and in the amplitude of the contingent negative variation
in the right hemisphere. We conclude that, in most healthy subjects, at least three sessions of α/θ training are necessary
to form an effective series providing considerable changes in the pattern of EEG potentials.
Neirofiziologiya/Neurophysiology, Vol. 39, No. 1, pp. 88–98, January–February, 2007. 相似文献
3.
We studied changes in the power spectra of EEG in the course of sessions of feedback by EEG characteristics (neurofeedback
sessions) and estimated the effects of neurofeedback on psychological and EEG correlates of voluntary attention. Indices of
the latter were estimated using Bourdon’s test (a correcture test) and Schulte’s tables. Twenty-nine reasonably healthy 10-to
13-year-old children took part in the study; they were divided into two groups, an experimental group (n = 12) and a control group (n = 15). The results obtained support the statement on noticeable changes in the functional state of the brain both immediately
in the course of a neurofeedback session and after a course of such trainings. Changes in the ratios of the spectral powers
of the beta1
vs theta rhythms and the low-frequency beta vs theta rhythms were found in EEG recorded from the sensorimotor zone of the right hemisphere (C4). The observed changes in
the spectral characteristics of EEG induced by the course of neurofeedback sessions were accompanied by the improvement of
a few indices of voluntary attention.
Neirofiziologiya/Neurophysiology, Vol. 38, Nos. 5/6, pp. 458–465, September–December, 2006. 相似文献
4.
In 76 healthy persons (right-handed men and women), we recorded background EEG and event-related potentials from the C3 and C4 sites; tests were performed within the framework of an experimental situation requiring internal measuring-off of the time intervals. To limit the interval, the tested person had to push a button; he/she did not know the precise value of the interval, which was preset by the experimenter, and was informed only of the lower and upper limits of this interval, 17 to 23 sec. The person obtained information about the coincidence/noncoincidence of the measured-off and preset intervals via visual feedback; the respective signal was presented 2 sec after measuring-off had been completed. In the case where the intervals coincided with each other, the person should confirm this by pushing the button next time (confirming push). We characterized the parameters of the measured-off time interval by the following indices: (i) measuring-off efficacy (accuracy of fitting the preset interval), (ii) estimation tendency (measured-off interval/preset standard interval ratio), and (iii) coefficient of variation (CV) of the measured-off interval. Features of the subject's personality were estimated using Eysenck's (PEN) and Cattell's (16PF) questionnaires. We found correlations of the powers of the background EEG rhythms (beta1, beta2, and alpha/theta ratio) and characteristics of the measured-off time interval. In addition, we observed significant positive correlations between the estimation tendency and extraversion index and between CV of the interval and urge toward domination and protension indices. Negative correlations were observed between the measuring-off efficacy and protension (suspiciousness), between the estimation tendency and anxiety, and between the CV of the interval and age of the subjects. We support the conclusion that correlations between the patterns of EEG potentials, peculiarities of measuring-off of the time interval, and psychological features of the personality are to a noticeable extent mediated by the individual specificity of the neurodynamics. 相似文献
5.
I. N. Konareva 《Neurophysiology》2007,39(2):137-146
In a group of 76 adults of both sexes, we examined interrelations between the level of aggressiveness of the individual (diagnosed
using the Buss-Durkee Hostility Inventory) and parameters of event-related EEG potentials (ERPs) recorded under conditions
of two behavioral test acts including a motor component. Within the framework of task A, the subject must push a button with
the shortest delay after an executory signal preceded by a warning signal; the time of sensorimotor reaction was measured.
Under these conditions, we recorded the contingent negative variayion (CNV) and the P300 potential. In the case of task B,
it was necessary to measure a definite time interval limited by two pushings of the button. Under these conditions, the readiness
potential (RP) was recorded in addition to the CNV and P300. The C3 and C4 leads were used (according to the 10–20 system);
the time constant of an amplification tract was 10 sec. Despite natural broad interindividual variability, high amplitudes
of the recorded ERPs (RP, CNV, and P300) in general corresponded to lower indices by scales of the Buss-Durkee inventory and
smaller values of the indices of aggressiveness and hostility. These interrelations are, probably, based on the fact that
both characteristics of aggressiveness of the personality and EEG amplitude parameters are to a considerable extent determined
by hereditary factors. It is believed that the respective peculiarities of the neurodynamic constitution of the individual
are to a great extent dependent on the specificities of organization and functioning of a few neurotransmitter (in particular,
aminergic) and neurohumoral systems.
Neirofiziologiya/Neurophysiology, Vol. 39, No. 2, pp. 154–164, March–April, 2007. 相似文献
6.
E. V. Evstaf’eva O. A. Zalata E. V. Repinskaya I. A. Evstaf’eva M. G. Shchegoleva S. L. Tymchenko N. M. Ovsyannikova 《Neurophysiology》2006,38(2):142-148
In 18-to 19-year-old students, the content of a number of microelements, as well as of calcium, in biologically stable tissues
(hair samples) was measured using X-ray fluorescent analysis. In the tested persons, we observed a certain deficit of main
elements (calcium, copper, and zinc), while in some persons the levels of toxic lead and strontium were exceeded. Correlation
analysis of the parameters of EEG potentials (current EEG and evoked and event-related potentials, EPs and ERPs, respectively)
showed the existence of a few significant (or close to those) correlations of the spectral powers of some rhythms and derivatives
of a few indices of the background EEG and more numerous cases of correlations of the parameters of EPs and ERPs (latencies
and amplitudes) with the contents of the studied elements. The physiological importance of metals, according to the number
of characteristics of EEG potentials that correlate with their contents, can be arranged in descending order as follows: As,
Zn > Ca > Cd > Pb > Sr. None of the studied parameters of EEG phenomena correlated with the level of copper. The strength
of correlations varied from weak to mild (0.29 < R < 0.50). The densest correlations were observed for the concentrations of toxic lead and cadmium. With respect to the characteristics
of ERPs, some of the elements under study demonstrated synergism (e.g., lead and arsenic), while others were in an antagonistic
relation (cadmium and calcium).
Neirofiziologiya/Neurophysiology, Vol. 38, No. 2, pp. 167–174, March–April, 2006. 相似文献
7.
8.
为考察鲫(Carassius auratus)幼鱼标准代谢的个体差异与运动力竭后代谢特征和行为的关系,在(25.0±0.5)℃条件下测定80尾鲫幼鱼标准代谢率(SMR),筛选出40尾实验鱼[体重(13.54±0.20)g,体长(8.05±0.07)cm],其中包括20尾高SMR个体和20尾低SMR个体,测定运动至力竭实验鱼的最大代谢率(MMR),并计算代谢空间(AS=MMR-SMR)、相对代谢空间(FAS)和过量耗氧(EPOC)总量,随后测定单尾鱼的快速启动行为[反应时间(RT)、最大线速度(Umax)、最大线加速度(Amax)和120ms移动距离(S120)]以及个性行为(勇敢性和活跃性)。结果显示鲫幼鱼的SMR与AS、FAS和EPOC总量均呈负相关,而与MMR不相关;MMR与AS、FAS和EPOC总量均呈正相关;协方差分析显示高SMR个体组的代谢恢复速率与低SMR个体组无显著差异。鲫幼鱼的SMR与快速启动行为的RT呈正相关,与Amax呈负相关,而与Umax和S120均不相关。在快速启动行为中,鲫幼鱼的RT与Umax、Amax和S120均呈负相关,而Umax与Amax和S120呈正相关。鲫幼鱼的SMR与其勇敢性指标如潜伏期(L)、曝露时间(ET)和探头频率(AF)以及活跃性指标如运动时间比(PTM)、撞墙频率(FHW)均不相关,但鲫幼鱼的PTM与FHW和ET呈正相关。研究表明在实验室条件下鲫幼鱼的能量代谢特征、快速启动和个性行为存在明显的个体差异现象,并且部分表型特征之间存在权衡,提示这些权衡可能是鲫幼鱼的生理、行为与栖息环境相互作用的综合结果。 相似文献
9.
I. N. Konareva 《Neurophysiology》2009,41(1):54-62
In a group of 70 adult subjects of both sexes, we estimated the levels of the need for achievement and its motivation (interpreted
as generalized characteristics of the state of the motivational sphere of a personality and diagnosed using questionnaires
of Orlov and Mehrabian) and examined the correlations of these estimates with spectral powers (SPs) of the frequency components
(rhythms) of the current background EEG (С3 and С4 leads according to the 10–20 system). Despite the fact that naturally high
interindividual variability exists, high estimates of the need for achievement correlated with medium values of the SPs of
most EEG frequency components (δ, θ, α, and β1 rhythms), low SPs of the β2 and γ rhythms, and higher values of the coefficient of reactivity (CR) of the α rhythm. A high level of the need for achievement
corresponded to higher SPs of the θ and γ rhythms and high CR of the α rhythm, a medium SP of this EEG component, and lower
SPs of the δ and β rhythms. The coefficient of interhemisphere asymmetry of the α rhythm was the highest at low values of
the studied psychological indices. Interrelations that we found in our study can be explained as follows: both the characteristics
of the need for achievement and motivation typical of a certain personality and the amplitude parameters of the EEG rhythms
observed in this individual depend significantly on genetically determined factors (in particular, on neurochemical ones).
These peculiarities of neurodynamic constitution of the individual are, to a considerable extent, due to the specificity of
organization and functioning of a few neurotransmitter (aminergic, in particular) and neurohumoral systems.
Neirofiziologiya/Neurophysiology, Vol. 41, No. 1, pp. 61–69, January–February, 2009. 相似文献
10.
Sahbi Chaibi Zied Sakka Tarek Lajnef Mounir Samet Abdennaceur Kachouri 《Biomedical signal processing and control》2013,8(6):927-934
Discrete high-frequency oscillations (HFOs) in the range of 80–500 Hz have previously been recorded from human epileptic brains using intracereberal EEG and seem to be a reliable biomarker of seizure onset zone in patients with intractable epilepsy. Visual marking of HFOs bursts is tedious, highly time-consuming particularly for analyzing long-term multichannel EEG recordings, inevitably subjective and can be error prone. Thus, the development of automatic, fast and robust detectors is necessary and crucial for HFOs investigation and for propelling their eventual clinical applications. This paper presents a proposed algorithm for detection and classification of HFOs, which is a combination of both smoothed Hilbert Huang Transform (HHT) and root mean square (RMS) feature. Performance evaluation in terms of sensitivity and false discovery rate (FDR) were respectively 90.72% and 8.23% related to process validation. Indeed, the proposed method was efficient in terms of high sensitivity in which the majority of HFOs visually identified by experienced reviewers was correctly detected, and had a lower FDR. This would mean that only a low rate of detected events was misclassified as candidate HFOs events. The presented software is extremely fast, suitable and can be considered a valuable clinical tool for HFOs investigation. 相似文献
11.
The mechanisms of hexavalent chromium(VI) induced DNA damage were unveiled by detecting products of single- and double-stranded DNA in the presence of glutathione. The absence of a detectable hydroxyl radical in the reactions indicates that DNA damage was exclusively by hypervalent chromium species. Polyacrylamide gel electrophoresis (PAGE) experiments with 32-mer single-stranded oligonucleotide and its complementary duplex revealed cleavages largely at purine bases with significant enhancement of such cleavages in the presence of a base. Quantitative estimations of bases released by HPLC before and after enzymatic digestion with exonucleases unequivocally established the excessive release of purine bases. This release was accompanied by the concomitant formation of phosphoglycolate as characterized by liquid chromatography-mass spectrometry (LC-MS). These data connote that the preponderance DNA damage is due to an oxidation specifically at H4' of the ribose moiety leading to the formation of apurinic sites. In addition to the oxidation at H4', DNA oxidation was also initiated through H5' site as evidenced by the identification of furfural. This pathway appears to be non-selective and more abundant for ssDNA as cleavages were observed at both purine and pyrimidine bases. Finally, the detection of guanidinohydantoin as a minor product points the involvement of an oxygen activated hypervalent chromium species, perhaps a peroxo-chromium species. Both major and minor pathways lead to cleavages at purine sites for ds-DNA and are consistent with the observation that DNA cleavage was enhanced in the presence of a base. In contrast, when hydrogen peroxide was added to the reactions, random DNA cleavages were apparent indicating involvement of multiple species including a hydroxyl radical. These data pinpoint mutation mechanisms induced by chromium(VI) in the presence of glutathione due to transversion either by inserting the wrong bases opposite to the apurinic sites during replication or by purine-purine mismatch. 相似文献
12.
Olano-Marin J Mueller JC Kempenaers B 《Evolution; international journal of organic evolution》2011,65(11):3175-3194
To understand the mechanisms behind heterozygosity-fitness correlations (HFC), it is necessary to employ large numbers of markers with known function and independently estimate the variation in inbreeding in the population. Here we genotyped 794 blue tits with 79 microsatellites that were distributed across 25 chromosomes and that were classified either as "functional" (N= 58) or "neutral" (N= 21). We found a positive effect of individual heterozygosity at multiple loci on clutch size, on the number of eggs sired by males, and on the number of recruits produced by males and females. We documented the occurrence of some consanguineous matings and found evidence for a particular type of population structure that can contribute to the occurrence of inbreeding. As the set of "neutral" loci provided more power to detect HFC and identity disequilibrium, we argue that "neutral" markers are better predictors of the effects of inbreeding. The number of significant effects at single loci did not exceed the expected number of false positives and no strong effects were associated with heterozygosity at "functional" markers. Thus, the HFC found here cannot be attributed to strong effects of the loci under study. 相似文献
13.
烟粉虱在温室内甘薯寄主上生物学特性的研究 总被引:6,自引:1,他引:6
对烟粉虱Bemisia tabaci(Gennadius)在温室内甘薯寄主上主要生物学特性的研究表明:烟粉氮成虫喜光、喜湿,晴朗高温时活动性强,但扩散飞行能力弱;多在白天交尾,多在中午产卵,具有强的惫鬃性.若虫一生脱皮3次,若虫(除一龄初期)固定生活。卵的孵化及成虫的羽化也多发生在中午。雌雄性比为1.628:1,成虫平均寿命14.25天,雌成虫平均寿命比雄成虫长6.9天,每雌平均产卵158.5粒。以两性生殖为主,也可孤雌生殖,两性生殖的产卵量及卵孵化率均高于孤雌生殖。 相似文献
14.
为了探讨延边朝鲜族和汉族脂联素基因启动子单核苷酸多态性(SNPs)与原发性高血压(EH)的关系, 文章采用PCR产物直接测序方法检测了220例EH患者和268例对照个体的脂联素启动子5个SNPs位点: -11426A>G(rs16861194)、-11391G>A(rs17300539)、-11377C>G(rs62620185)、-11156insCA(rs60806105)、-11043C>T(rs76786086), 氧化酶法测定空腹血糖、甘油三酯、总胆固醇、低密度脂蛋白、高密度脂蛋白, 酶联免疫吸附法(ELISA)测定血浆脂联素和胰岛素。结果显示: (1) -11426A>G、-11377C>G 和-11156insCA 3个位点具有多态性, 且它们的基因型频率分布符合Hardy-Weinberg平衡定律(P>0.05), -11391G>A和-11043C>T位点无多态性; (2) -11426A>G和-11156insCA呈完全连锁不平衡(D’=1; r2=1); (3) -11426G基因频率比较, 朝鲜族(21.10%)高于汉族(12.05%), 汉族EH组高于对照组; -11377C>G的基因型和基因频率在朝鲜族和汉族间及同一民族内EH组和对照组间比较均无统计学意义(P>0.05); (4)单倍型?11426G -11377C的频率, 汉族EH组高于对照组(P<0.05), 朝鲜族EH组和对照组比较无统计学意义(P>0.05); (5)EH组的血浆脂联素水平明显低于对照组(P<0.001)。据此得出结论: (1)首次发现?11426A>G和?11156insCA呈完全连锁不平衡, -11426 A>G的多态性在朝鲜族和汉族中存在民族差异; (2) -11426 G和-11426G -11377C是延边汉族EH的危险因子和危险单倍型, 但不是朝鲜族的; (3)低血浆脂联素是延边朝鲜族和汉族EH的重要危险因素; (4)血浆脂联素水平与-11426A>G基因型无关。 相似文献
15.
有机酸存在下小麦体内Cd的生物毒性和植物络合素(PCs)合成的关系 总被引:5,自引:0,他引:5
采用溶液培养方式 ,研究了有机酸存在下小麦体内 Cd的生物毒性和植物络合素 (PCs)合成的相关关系 ,试图寻求一种与小麦体内 Cd的生物毒性高度相关的评价指标。结果显示 ,Cd胁迫对小麦产生明显的毒害效应并诱导小麦根系内 PCs的大量合成。EDTA、DTPA、柠檬酸、苹果酸和草酸的适量供应可不同程度减轻或消除 Cd的生物毒性 ,其强弱顺序为 EDTA >DTPA 柠檬酸 >苹果酸≈草酸。与此同时 ,小麦根系内 PCs的诱导量也有明显下降 ,与 Cd的生物毒性保持一定的线性关系 ,且在EDTA、DTPA和柠檬酸供应下尤为显著。表明 PCs可以作为一项敏感的生化指标 (biochem ical indicator)用来评价和预测环境中 Cd的污染 ,并有望成为重金属生物有效性评价系统中一种新的补充方法 相似文献
16.
The study of hybrid zones is central to our understanding of the genetic basis of reproductive isolation and speciation, yet very little is known about the extent and significance of hybrid zones in marine fishes. We examined the population structure of cod in the transition area between the North Sea and the Baltic Sea employing nine microsatellite loci. Genetic differentiation between the North Sea sample and the rest increased along a transect to the Baltic proper, with a large increase in level of differentiation occurring in the Western Baltic area. Our objective was to determine whether this pattern was caused purely by varying degrees of mechanical mixing of North Sea and Baltic Sea cod or by interbreeding and formation of a hybrid swarm. Simulation studies revealed that traditional Hardy-Weinberg analysis did not have sufficient power for detection of a Wahlund effect. However, using a model-based clustering method for individual admixture analysis, we were able to demonstrate the existence of intermediate genotypes in all samples from the transition area. Accordingly, our data were explained best by a model of a hybrid swarm flanked by pure nonadmixed populations in the North Sea and the Baltic Sea proper. Significant correlation of gene identities across loci (gametic phase disequilibrium) was found only in a sample from the Western Baltic, suggesting this area as the centre of the apparent hybrid zone. A hybrid zone for cod in the ecotone between the high-saline North Sea and the low-saline Baltic Sea is discussed in relation to its possible origin and maintenance, and in relation to a classical study of haemoglobin variation in cod from the Baltic Sea/Danish Belt Sea, suggesting mixing of two divergent populations without interbreeding. 相似文献
17.
Ali Azizi Javad Hadian Mansour Gholami Wolfgang Friedt Bernd Honermeier 《化学与生物多样性》2012,9(12):2784-2801
In total, 42 accessions of Origanum vulgare L., mostly originating from Europe, were evaluated, to detect molecular, quantitative morphological, and chemotype polymorphisms and to discover possible correlations between them. Twelve traits related to morphological characteristics were measured. The components in the essential oils were identified by GC/MS analysis, and the oil contents of 18 major compounds were determined. A total of 477 molecular polymorphisms including 214 AFLP (amplified fragment length polymorphism) and 263 SAMPL (selectively amplified microsatellite polymorphic loci) were used for genotyping. Euclidean distances of morphological and chemotypic data and genetic distances (1 – Dice's similarity) of molecular markers were compared by applying Mantel tests to ascertain the congruencies between them. A relatively high correlation between chemotypic patterns and genetic markers was identified, while a lower correlation was found between the morphological and genetic matrices. Pairwise analyses of correlation among all traits showed that the stem diameter was correlated to the essential‐oil yield and the carvacrol content. Cluster analysis, population inference, and principal component analysis revealed a broad genetic and chemical variation among the accessions. The knowledge of these diversities, found in this study, will allow a plant improvement of Origanum vulgare related to pharmaceutical and spice uses. 相似文献
18.
Antonio Martínez-Richa 《Carbohydrate polymers》2012,87(3):2129-2136
Z-average root mean square end-to-end distance 〈ro2〉z1/2 and radius of gyration 〈so2〉z1/2 for 13 samples of O-(2-hydroxyethyl)cellulose (HEC) of different molecular weights were derived from Gel Permeation Chromatography and intrinsic viscosity measurements with water as a solvent. At 40 °C and pH 4.5, contraction of chain dimensions is observed, compared with the sizes observed under neutral conditions at room temperature. The effect is lower for samples with higher molecular weights. Values of 〈ro2〉40/DPz also indicate that chain flexibility increases at higher temperature and acidic conditions. From the analysis of molecular weight dependence of 〈so2〉 z1/2, Flory exponent υ was derived at 40 °C and pH 4.5. A value of υ = 0.70 ± 0.02 was recorded, which indicates that a relatively stiff chain is present under these conditions. Finally, different equations to calculate persistence length Lp were evaluated. Values in the range of 260-400 Å were derived for persistence length. Implications of chain conformation in the enzymatic action of cellulases are also discussed. 相似文献
19.
Detao Liu Jun Li Rendang Yang Lihuan Mo Lianghui Huang Qifeng Chen Kefu Chen 《Carbohydrate polymers》2008,74(2):290-300
In this work, the moulded cellulose fibers/MPU-20 composites (CFMCs) with apparent specific gravity lower than 100 kg/m3 and thickness of 20–200 mm have been successfully manufactured using a new design of steam injection technology and equipment. It was found that the CFMCs have good cushioning properties, with a cushion factor lower than 4. Two yield deformation stages were observed in the compressive process. Compressive stress–strain and cushion factor-stain curves were measured as a function of steam injection pressure, transmission time, holding time, MPU-20 resin dosage and apparent specific gravity. Chemical groups, crystallinity, and thermal properties of samples were studied through the use of FTIR spectroscopy, X-ray diffraction (XRD), and DTA–TGA. In addition, the microstructure and morphology were investigated by scanning electron microscope (SEM) and atomic force microscope (AFM). 相似文献
20.
休眠是植物种子对环境变化的适应机制,其机理至今未完全清楚阐明。前期对种子休眠机制的研究主要集中在激素调节上,近期的研究结果表明,一氧化氮(nitric oxide,NO)参与打破种子的休眠,并与其所引起的种子中活性氧的变化有关。本文简要综述活性氮(reactive nitrogen species,RNS)、活性氧(reactive oxygen species,R0s)和植物激素在种子休眠解除中的作用及相互关系研究进展。 相似文献