【作者】 吕江腾；

【导师】 蒲慕明； 章晓辉；

【作者基本信息】 中国科学院研究生院（上海生命科学研究院） ， 神经生物学， 2006， 博士

【摘要】 神经元的电活动能对皮层神经元环路中兴奋性突触传递效率进行长时程修饰。本文中我们报告这种长时程突触可塑性具有靶细胞类型依赖的特性。在大鼠体感皮层(somatosensory cortex)第二/三层(layer 2/3),锥体细胞(pyramidal cell,PC)可同时在快速放电(fast spiking,FS)和低阈值放电(low-threshold spiking,LTS)中间神经元上形成突触连接。突触前后神经元不同时序(timing)的相关性放电(correlated spiking)可以长时程增强(long-term potentiation,LTP)或减弱(long-term depression,LTD)锥体细胞到LTS细胞的突触(PC-LTS)传递。然而,不同时序和频率的相关性放电只能在锥体细胞到FS细胞的突触(PC-FS)上产生LTD。同时我们发现:相比PC-LTS突触, PC-FS突触只具有极低水平的NMDA(N-methyl-D-aspartate)亚型谷氨酸受体。进一步研究表明:在PC-LTS突触上,LTP的产生依赖NMDA受体的激活;而在两种突触上产生LTD需要代谢型(metabotropic)谷氨酸受体的激活,与NMDA受体没有关系。这种靶细胞类型特异的突触可塑性为皮层局部环路信息的差异性处理和储存提供了基础。更多还原

【Abstract】 Spiking activity can induce persistent modification of excitatory synapses in cortical circuits. Here we report that such modification exhibits target cell-dependent properties. In layer 2/3 of the somatosensory cortex, the pyramical cell (PC) forms divergent synapses on fast spiking (FS) and low-threshold spiking (LTS) interneurons. Correlated pre- and postsynaptic spiking induced long-term potentiation (LTP) or depression (LTD) at PC-LTS synapses, depending on the timing of pre/post spiking. However, regardless the timing and frequency of spiking, correlated activity induced only LTD at PC-FS synapses, which have a much lower level of N-methyl-D-aspartate subtype of glutamate receptors (NMDARs) than that of PC-LTS synapses. Furthermore, activation of NMDARs was required for LTP at PC-LTS synapses, whereas activation of metabotropic glutamate receptors (mGluRs) rather than NMDARs was required for LTD of both PC-LTS and PC-FS synapses. This target cell-specific synaptic plasticity allows for differential processing and storage of information in cortical local circuits.更多还原