Differential Effect of TEA on Long-Term Synaptic Modification in Hippocampal CA1 and Dentate Gyrus in vitro

The effectiveness of tetraethylammonium (TEA) and high-frequency stimulation (HFS) in inducing long-term synaptic modification is compared in CA1 and dentate gyrus (DG) in vitro. High-frequency stimulation induces long-term potentiation (LTP) at synapses of both perforant path-DG granule cell and Schaffer collateral-CA1 pyramidal cell pathways. By contrast, TEA (25 mM) induces long-term depression in DG while inducing LTP in CA1. The mechanisms underlying the differential effect of TEA in CA1 and DG were investigated. It was observed that T-type voltage-dependent calcium channel (VDCC) blocker, Ni²⁺ (50 μM), partially blocked TEA-induced LTP in CA1. A complete blockade of the TEA-induced LTP occurred when Ni²⁺ was applied together with the NMDA receptor antagonist, D-APV. The L-type VDCC blocker, nifidipine (20 μM), had no effect on CA1 TEA-induced LTP. In DG of the same slice, TEA actually induced long-term depression (LTD) instead of LTP, an effect that was blocked by D-APV. Neither T-type nor L-type VDCC blockade could prevent this LTD. When the calcium concentration in the perfusion medium was increased, TEA induced a weak LTP in DG that was blocked by Ni²⁺. During exposure to TEA, the magnitude of field EPSPs was increased in both CA1 and DG, but the increase was substantially greater in CA1. Tetraethylammonium application also was associated with a large, late EPSP component in CA1 that persisted even after severing the connections between CA3 and CA1. All of the TEA effects in CA1, however, were dramatically reduced by Ni²⁺. The results of this study indicate that TEA indirectly acts via both T-type VDCCs and NMDA receptors in CA1 and, as a consequence, induces LTP. By contrast, TEA indirectly acts via only NMDA receptors in DG and results in LTD. The results raise the possibility of a major synaptic difference in the density and/or distribution of T-type VDCCs and NMDA receptors in CA1 and DG of the rat hippocampus.     

视觉工作记忆对前注意阶段注意定向的调节

在注意阶段,视觉工作记忆与注意共享某些特征时,视觉工作记忆内容会引导注意定向。在前注意阶段的影响又是如何？对此问题的研究却很少见,本研究采用工作记忆与基于特征的视觉搜索相结合的任务深入探讨了此问题。研究结果发现：即使在前注意阶段,注意定向也会受到视觉工作记忆自上而下的调节。然而与注意阶段不同的是：当视觉工作记忆内容与随后视觉搜索任务的目标相关时,与记忆内容匹配的搜索项目会引导注意定向到该项目所在的位置,但只有此项目作为分心物时,才会明显地延迟对靶子的加工,而此项目作为靶子时,这种影响并不明显;当视觉工作记忆中保持的项目与随后视觉搜索任务的目标无关时,注意会忽略视觉工作记忆中保持的项目,有效地检测靶子     

Neuropsychological findings of extrapontine myelinolysis without central pontine myelinolysis

Central pontine myelinolysis (CPM) and extrapontine myelinolysis (EPM) are well recognized syndromes related to the rapid correction of hyponatremia, which are reported to show brain stem signs and various movement disorders. Cognitive dysfunction and neuropsychological findings, however, have seldom been reported. Cognitive manifestations in osmotic myelinolysis may have been underestimated due to the prominent brain stem symptoms and movement disorders. We report a case of EPM without CPM and describe the neuropsychological findings of EPM. The absence of CPM in this case made it possible to test neuropsychological function in the acute stage. Neuropsychological testing showed severe impairment of attention, verbal and visual memory, visuospatial function, and frontal/executive function. Language and language-related functions were normal except naming.     

结直肠癌诊断模式的若干思考

结直肠癌是常见的消化道恶性肿瘤,然而在临床上得到诊断时大多已经到了中晚期,错过了最佳的治疗时机。近年来,随着基因相关技术及生物信息技术的迅猛发展,结直肠癌诊断方法得到不断改进,但早期诊断仍不尽如人意。因此现有的诊断模式值得我们去深思,从哲学意义上探索更为完善的诊断模式。     

十五年来中国男性择偶标准的变化

对《中国妇女》1985年至2000年15年间每隔5年选择一年,并在每一季度中选择一期杂志,统计男性刊登的征婚启事,总共得到332例。采用统计学方法进行定量研究。发现中国男性在15年间对自身的人品、财产、相貌的重视程度显著增高,对自身的婚史和事业的重视程度明显降低;对女方的持家能力的重视程度显著增高,对女方的健康和工作的重视程度显著降低。当代中国男性的择偶标准随时间的推移有了明显的变化,但仍受到中国传统观念的影响。     

经济法试题DIF的参数法检测研究

该研究基于项目反应理论的Samejima等级反应模型(GRM),在MULTILOG软件支持下,应用参数检测方法,对某年度全国性资格考试的某科目试卷中经济法部分的21个项目做了DIF检测分析。结果如下:存在性别DIF的项目一个,存在民族DIF的项目四个,存在工作性质DIF的项目一个。其中项目68在民族层面上表现为一致性DIF,项目64既存在民族DIF又存在工作性质DIF。通过对项目统计量、反应曲线的分析和专家的讨论,文章最后还分析了产生这些DIF的几个可能的原因。     

在国际道德经论坛闭幕式上的致辞

女士们,先生们: 今天,我有幸参加国际道德经论坛闭幕典礼这样一个盛事,感到非常高兴.我对论坛的圆满成功表示热烈祝贺! 崇尚和谐、爱好和平,是中华民族高尚的精神品格.在春秋战国时期,中华民族的先哲们就确立起"和为贵"、"和而不同"、"重生贵和"的价值理念.     

构建社会主义和谐社会中的道德建设新指向

构建社会主义和谐社会的命题,要求实现道德建设"由圣入凡"的转变.这种转变的新指向是:以日常生活批判实现从传统道德向现代道德的转化,把以人为本与现代性"平民化人格"联系起来,以生态和谐观念寻求公德与私德的统一.     

理性、中道与幸福——探讨亚里士多德的道德选择理论

道德选择理论是亚里士多德伦理思想中的重要内容。本文首先三个方面研究了亚里士多德的道德选择理论:一、亚里士多德论道德选择的理论前提;二、亚里士多德论道德选择的依据;三、亚里士多德论道德选择的目标。其次,从西方哲学史的宏观背景中就亚里士多德的道德选择理论的成败得失进行讨论。通过研究古希腊亚里士多德的道德选择理论,这将有助于我们了解道德选择在道德理论和道德实践中的重要作用。     

乌托邦和拓扑发生学——比较康德的主体和海德格尔的此-在

本文重点比较了康德与海德格尔对主体的观点.文章通过对此二人的引述和论证展示出,虽然他们都承认主体的自发性,但是康德的主体的自发性是通过先验主体根本不在时空之中来保证的,而海德格尔的主体(此-在)的自发性却体现在此-在本身就是"时空发生".康德的主体是纯粹的,不属于感性的,是不可以对象化的;而海德格尔的此-在虽然也不可以对象化,但是由于此-在本身就是"时空发生",所以海德格尔的此-在并不是纯粹的.简单地说,康德的主体是乌托邦的,海德格尔的此-在是拓扑发生学的.