12 resultados para paradigms

em Chinese Academy of Sciences Institutional Repositories Grid Portal


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The effects of ketamine, an N-methyl-D-aspartate (NMDA) antagonist, on memory in animals have been limited to the sub-anesthetic dose given prior to training in previous studies. We evaluated the effects of post-training anesthetic doses of ketamine to se

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Effects of morphine on acquisition and retrieval of memory have been proven in the avoidance paradigms. In present study, we used a two-trial recognition Y-maze to test the effects of acute morphine and morphine withdrawal on spatial recognition memory. T

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The central nervous system exhibits remarkable plasticity in early life. Prenatal morphine exposure may induce adverse behavioral effects on the neonate and the developing offspring. In the present study, we investigated the effect of prenatal morphine exposure (daily from embryonic days 12-16, 20 mg/kg) on 11-day-old chicks using two forms of spatial paradigms: one trial detour behavior task in which animals must bypass an obstacle to reach the desired goal without any training and detour learning task which required several trials of training to reach the detour criterion. The results showed that, on the condition that chicks could successfully detour in the first trial, morphine exposed chicks exhibited longer detour latency to finish the task, coupled by a preference for turning right versus turning left. In contrast, no significant difference in learning and memory was found in detour learning task between morphine exposed chicks and saline chicks. These findings suggest specific behavioral changes associated with prenatal exposure to opioids during mid to late gestation, also raise attention to the possible health hazard from pregnancy drug use in everyday life. (C) 2010 ISDN. Published by Elsevier Ltd. All rights reserved.

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According to outdated paradigms humic substances (HS) are considered to be refractory or inert that do not directly interact with aquatic organisms. However, they are taken up and induce biotransformation activities and may act as hormone-like substances. In the present study, we tested whether HS can interfere with endocrine regulation in the amphibian Xenopus laevis. In order to exclude contamination with phyto-hormones, which may occur in environmental isolates, the artificial HS 1500 was applied. The in vivo results showed that HS 1500 causes significant estrogenic effects on X. laevis during its larval development and results of semi-quantitative RT-PCR revealed a marked increase of the estrogenic biomarker estrogen receptor mRNA (ER-mRNA). Furthermore, preliminary RT-PCR results showed that the thyroid-stimulating hormone (TSH beta-mRNA) is enhanced after exposure to HS1500, indicating a weak adverse effect on T3/T4 availability. Hence, HS may have estrogenic and anti-thyroidal effects on aquatic animals, and therefore may influence the structure of aquatic communities and they may be considered environmental signaling chemicals. (c) 2005 Elsevier Ltd. All rights reserved.

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在激烈的市场竞争中,过程企业不仅要重视技术、更要加强管理,实现全局优化运行。提高过程企业的市场竞争能力必须全面综合集成人、组织、战略管理、经营管理、过程管理及信息自动化技术等因素。本文以石化企业为背景,对过程企业面临的问题及发展趋势进行了分析,并且对过程企业管理模式、过程企业的体系结构以及过程集成与优化技术进行了探讨。

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系统的决策控制活动依赖于系统内部的控制结构,制造系统的控制结构是先进制造与自动化领域的重要研究课题。制造系统的控制结构与计算机技术、生产设备自动化水平及制造模式等因素有关。早期的制造系统采用集中控制结构,而柔性制造系统和计算机集成制造系统多采用递阶控制结构。目前制造业已进入一个新时代,传统生产模式和企业结构无法适应不可预测的激烈的环境变化。因此,未来制造系统需要具备快速变化能力的动态控制结构

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整子制造系统是智能制造计划中提出的一种未来的制造模式,本文对其概念、理论和研究状况进行了介绍和分析.整子是构造制造系统的一种模块,它具有自治性及合作性,而整子制造系统则追求快速适应环境变化的能力.整子制造系统采用了一种松弛的动态递阶控制结构.目前整子制造系统仍然处于对“下一代制造模式”的研究阶段,离实际应用还有一定的距离。

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In recent years, the deficit of inhibition has become an important reason for explaining addiction. Response inhibition resembles the compulsive drug seeking behavior and it is the basement of addiction inhibition deficits. However, there were no enough evidence for the relationship between addiction and response inhibition deficits and the results of the neuro mechanisms studies remains unclear. Few studies has focused on the exploring the heroin users. Among those paradigms for study response inhibition deficits, stop signal is a very suitable model for the representation of compulsive drug seeking, but only a few researches has worked on this paradigm. In this study, we selected about 100 heroin abusers and had behaviour and neuro imaging scannings for investigating the response inhibition deficits. The behaviour researches found: first, the chronic heroin users had longer reaction time than control group and this reaction time were not affected by stop signals in heroin users. Second, heroin users had less waiting time than control group and they were more impulsive but less flexibility. Their erro monitoring and flexibale adjustment ability decreased. Third, the SSRT of heroin users was significantly longer than control group. These results suggested that the inhibition of heroin users were impaired. Further investigation showed that the SSRT of heroin users had positive correlation of four factor scores of ASI and the macro correlation coefficient was factor three of drug use. This correlation suggested that drug use was the main reason of inhibition deficits. fMRI results mainly focused on the ANOVA analysis for group difference. First, there was no intensity difference in M1 and SMA brain areas between the two groups. Second, heroin users had less activation in right dorsalateral prefrontal cortex, right inferior prefrontal cortex and anterior cingulated cortex, while in bilateral striatum and amygdala, heroin users had more activation than control group. The right prefrontal cortex was indentified as the main inhibition brain area. The anterior cingulated cortex has relationship with erro monitoring and amygdale was an important brain area for impulsivity and emotion control. The network of these brain areas was envovled in impulsivity and inhibition and it was suggested the mainly damaged network for heroin users’ disinhibition. We also investigated the gray matter changes of heroin users and found that chonic heroin use made their gray matter density decreased in prefrontal cortex (including bilateral dorsalateral prefrontal cortex, obital frontal cortex, inferior prefrontal cortex) and anterior cingulated cortex. The gray matter density in these brain regions had negative correlation with drug use duration. In conclusion, we indentified the disinhibition of heroin users and its neuro mechanism. Their compulsivity brain areas had more activation than control group and their inhibition brain areas had less activation than normal control. On the other side, the biological mechanism of this activation changes was the gray matter density decrease in these brain areas.

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A dual task paradigm which consisted of RSVP task and orthogonal spatial cuing task was adopted to study the effects of perceptual load and cue modality on attention capture. This dual task paradigm was modified from Santangelo’s tasks in which only the high load condition used the dual task. Experiment 1 found that in the low perceptual load condition, the visual cues showed advantage in capturing attention compared with the audiovisual ones. While in the high perceptual load condition, the audiovisual cues were better to capture attention. SOA was introduced into Experiment 2, 3 and 4 in order to help clarify the relationship among perceptual load, cuing modality and attention capture. The low load visual cuing task testified the period time course characteristics in attention capture which was found by Liang et.al. Differing from Liang’s conclusion that attention capture occurred at 333ms, attention capture occurred at 50ms here which might be caused by the different paradigms used. Moreover, the similar period time course was found in high load audiovisual cuing task when SOA equaled 50ms. And no such period time course characteristics were found neither in the high load visual cuing task nor the low load audiovisual cuing task. These results found the period time course characteristics in attention capture. And it was suggested that these characteristics were influenced by perceptual load and cuing modality.

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By two different cue paradigms to cue target’s location or locations of all stimuli, this study is to discuss the search efficiency in different search modes. The research includes three experiments. The main results are as follows: The first experiment explores whether cueing target’s location has impact on vis-ual search performance under different search modes (parallel search and serial search). The results are: cueing target’s location has no facilitation effect in parallel search condition while has facilitation effect in serial search condition, the effect reflects the diffidence in slope of reaction time. In the second experiment, we want to explore whether cueing all stimuli’s loca-tions has impact on visual search performance under different search modes. The re-sults show that: cueing all stimuli’s locations has no facilitation effect in parallel search condition but has facilitation effect in serial search condition, the effect reflects the diffidence in intercept of reaction time. The third experiment is to explore the time course of facilitation effect in serial search. The result shows that only a 50ms which cueing all stimuli’s locations has fa-cilitation effect, with the longer cueing time, the more facilitation effect.

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It is well established that memory functioning deteriorates with advancing age. However, research indicates that the magnitude of age-related memory deficits varies across different types of memory, and broad individual differences can be observed in the rate and timing of memory aging. The general aim of this study was to investigate the selectivity and variability of memory functioning in relation to anxiety. Firstly, memory effectiveness was assessed in episodic memory tasks with reality monitoring and external source monitoring paradigms, semantic memory tasks referred to general knowledge and word fluency, and perceptual priming task reflected in word completion. According to the scores on trait version of STAI, the high-trait and low-trait anxious subjects were screened respectively from young and old participants matched for educational level. Secondly, based on the results of the first part, concurrent primary and secondary tasks with probe technique assessing spare processing capacity were used to explore the relation between memory efficiency and anxiety. The first main findings were that: (a) there were no age-related differences in semantic memory assessed by general knowledge and PRS, whereas age effects were observed in episodic memory and semantic memory assessed by word fluency with stringent time restraints. (b) Furthermore, comparison of age-related deficits in source and item was not related to the presentation ways and encoding effort for source, but was affected by types of source. Specifically, memory was more sensitive to aging than item memory in external source monitoring processes involved in discriminating two external sources (i.e., female vs. male voices), but not in reality monitoring processes in discriminating between internal and external sources (i.e., acting vs. listening). The second main findings were that: (a) Anxiety had no effects on the effectiveness and efficiency of semantic memory in recall of general knowledge and PRS, but impaired those of semantic memory in word fluency. (b) The effects of anxiety on episodic memory were different between the old and the young. Both the effectiveness and the efficiency of episodic memory of the old were affected adversely by anxiety. More importantly, source recall in external source monitoring processes was observed to be more vulnerable to anxiety than item memory. The effectiveness of episodic memory of the young was relatively unrelated to anxiety, while anxiety might have adverse effect on their memory efficiency. These results indicated that: First, the selectivity of age-related memory deficits existed not only between memory systems, but also within episodic memory system. The tendency to forget the source even when the fact was retained in external source monitoring was suggested to be a specific feature of cognitive aging. Second, anxiety had adverse impact on the individual differences in memory aging, and mediated partial age-related differences in episodic memory performance.

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Credible and stable animal behavioral models are necessary to research the mechanisms of addiction in vivo, especially to study the relationship between memory or stress and drug addiction, which has been one of the focuses in this field. So the object of this study was to observe the influences of several factors on the behavioral effects of morphine shown in the paradigms of conditioned place preference (CPP) and locomotor activity (LA), and to explore the effects of adrenalectomy on LA induced by morphine in rats. In addition, the cortexes of rats were examined, which were exposed to chronic administration of several doses of morphine with or without foot shock. Moreover, a new behavioral model was built to quantify the motivation of drug seeking. The results showed that CPP was more sensitive to low dose of morphine than to high dose. The period of experiment could be shortened by increasing the training times everyday, whereas in this way the dose of morphine should be low enough to avoid the impact between the near two exposures to morphine. Effects of chronic administration of morphine on LA in rats were dose- and time- dependent, which supplied evidence to choose parameters in other behavioral models. The results obtained by the simplified LA paradigm showed that hyperactivity of low dose of morphine following hypoactivity, and naloxone had no effects on LA but blocked the locomotion effects of morphine. Obvious effects of morphine on LA of rats might depend on a reasonable level of plasma corticosterone, which may determine individual vulnerability to drug addiction. Stress may also potentiate the vulnerability by aggravating damage to cortex of rats induced by drug dose-dependently, which is suggested by the results of histological examination. The result that frontal and temporal cortexes and hippocampus were injured suggests that there may be a close relationship between memory and drug addiction. It was showed that the new behavioral model on the basis of Morris water maze might be used to quantify the motivation of drug-craving.