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151.
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Hyeon Son Yun-Fei Lu Min Zhuo Ottavio Arancio Eric R. Kandel Robert D. Hawkins 《Learning & memory (Cold Spring Harbor, N.Y.)》1998,5(3):231-245
Previous results have suggested that cGMP is involved in hippocampal long-term potentiation (LTP), perhaps as the presynaptic effector of a retrograde messenger. However, other studies have failed to replicate some of those results, making the role of cGMP uncertain. We therefore reexamined this question and identified several variables that can affect the contribution of cGMP. First, brief perfusion with 8-Br–cGMP before weak tetanic stimulation produced long-lasting potentiation in the CA1 region of hippocampal slices, but more prolonged perfusion with 8-Br–cGMP before the tetanus did not produce long-lasting potentiation. Second, the activity-dependent long-lasting potentiation by cGMP analogs was reduced when NMDA receptors were completely blocked, indicating that NMDA receptor activation contributes to, but is not required for, the potentiation. The amount of reduction of the potentiation differed with different protocols, and in some cases could be complete. Third, LTP produced by strong tetanic stimulation in the stratum radiatum of CA1 (which expresses eNOS) was blocked by inhibitors of soluble guanylyl cyclase or cGMP-dependent protein kinase, but LTP in the stratum oriens (which does not express eNOS) was not. The results of these experiments should help to explain some of the discrepant findings from previous studies, and, in addition, may provide insights into the mechanisms and functional role of the cGMP-dependent component of LTP. 相似文献
153.
Selective Abolition of the NMDA Component of Long-Term Potentiation in Mice Lacking mGluR5 总被引:6,自引:0,他引:6 下载免费PDF全文
Zhengping Jia YouMing Lu Jeff Henderson Franco Taverna Carmelo Romano Wanda Abramow-Newerly J. Martin Wojtowicz John Roder 《Learning & memory (Cold Spring Harbor, N.Y.)》1998,5(4):331-343
The mechanisms underlying the differential expression of long-term potentiation (LTP) by AMPA and NMDA receptors, are unknown, but could involve G-protein-linked metabotropic glutamate receptors. To investigate this hypothesis we created mutant mice that expressed no metabotropic glutamate receptor 5 (mGluR5), but showed normal development. In an earlier study of these mice we analyzed field-excitatory postsynaptic potential (fEPSPs) in CA1 region of the hippocampus and found a small decrease; possibly arising from changes in the NMDAR-mediated component of synaptic transmission. In the present study we used whole-cell patch clamp recordings of evoked excitatory postsynaptic currents (EPSCs) in CA1 pyramidal neurons to identify the AMPAR- and NMDAR-mediated components of LTP. Recordings from control mice following tetanus, or agonist application (IS, 3R-1-amino-cyclopentane 1,3-dicarboxylic acid) (ACPD), revealed equal enhancement of the AMPA and NMDA receptor-mediated components. In contrast, CA1 neurons from mGluR5-deficient mice showed a complete loss of the NMDA-receptor-mediated component of LTP (LTPNMDA), but normal LTP of the AMPA-receptor-mediated component (LTPAMPA). This selective loss of LTPNMDA was seen in three different genotypic backgrounds and was apparent at all holding potentials (−70 mV to +20 mV). Furthermore, the LTPNMDA deficit in mGluR5 mutant mice could be rescued by stimulating protein kinase C (PKC) with 4β-phorbol-12,13-dibutyrate (PDBu). These results suggest that PKC may couple the postsynaptic mGluR5 to the NMDA-receptor potentiation during LTP, and that this signaling mechanism is distinct from LTPAMPA. Differential enhancement of AMPAR and NMDA receptors by mGluR5 also supports a postsynaptic locus for LTP. 相似文献
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155.
本文是对皮亚杰“物体守恒”实验的验证。从而探讨了4—9岁儿童在形成守恒概念中的逻辑思惟发展过程,为编制智力测验量表提供了有关参考数据。 相似文献
156.
教材内容的情感性分析及其处理策略 总被引:28,自引:3,他引:25
人们对教材的教学心理学分析研究相对较少,仅有的也多囿于认知维度。奥苏贝尔在其意义学习理论框架下研究了教材的意义性及其学习条件问题,并提出了著名的处理教材内容的先行组织者策略,然其研究仍属认知维度。其实,教材也是构成教学中情感现象的一个重要源点,对其进行情感性分析研究,将有助于从情感维度系统优化教学。故本文对教材内容进行较系统的情感分析,归纳为蕴涵显性、隐性、悟性和中性情感因素的四大类,并在教学实验 相似文献
157.
教育无国界是有识之士的共识,也是不可逆转的潮流。中国采取在世界各地建立孔子学院的形式加大吐人对汉语和中国的教育的认识,文章从孔子学院在世界各地的运作形式,阐述了孔子学院发展近四年多来对世界的影响和世界对汉语和中国教育的国际化认同以及对有关的问题进行了反思。 相似文献
158.
职业技术教育是随产业的产生而产生、随产业的发展而发展的,这是职业技术教育产生与发展的原始动因和持续动力,也是我们考证职业教育何时形成的重要判断依据。在我国奴隶社会之前,社会经济文化的发展还没有导致社会经济产业化的形成,人们之间的社会分工还没有达到专门的职业化。那时,技术技能的学习与传授是在日常生活和日常劳动中实现的,是偶然的、分散的、带有一定随机性的,没有专门的教育场所和教育人员。夏商周三代,少数脑力劳动者成为专门掌管文化及农业、手工业、商业等行业的官吏,实行“子习父学”的职官教育,奴隶和平民没有接受专业技术教育的权利。春秋桓、管时期,社会生产力进一步发展,产业分工越来越细致化、专职化,产业经济的发展要求具备相应的职业教育;齐桓公为称霸诸侯任用管仲为相,推行“四民分业定居制度,从而最早产生了我国历史上真正意义的职业教育。 相似文献
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The main purpose of this study was to investigate possible differences in speed and accuracy of motor execution among female soccer players in an Expert Soccer group, a Novice Soccer group, and a Closed-skill Athlete group. There were two main findings. Firstly, both soccer groups performed better than the Closed-skill Athletes on speed and accuracy of motor execution. Secondly, there were no significant differences between Expert and Novice soccer players in the speed and accuracy of motor execution. 相似文献