Morphological bases of spatial summation properties of cat V1 neurons
文献类型：学位论文
| 作者 | Song XM(宋雪梅) |
| 学位类别 | 博士 |
| 答辩日期 | 2007-05-25 |
| 授予单位 | 中国科学院上海生命科学研究院 |
| 授予地点 | 上海生命科学研究院 |
| 导师 | 李朝义 |
| 关键词 | 经典感受野 感受野外区 动态特征 易化 抑制 锥体细胞 受体 轴突 树突 树突棘 |
| 其他题名 | Morphological bases of spatial summation properties of cat V1 neurons |
| 学位专业 | 神经生物学 |
| 中文摘要 | 第一部分 近年来研究报道指出：V1区神经元传统感受野和空间整合范围依赖于刺激的对比度。我们重新检查了48个猫V1区神经元的这些特征，观察到：所有这些细胞都具有固定的传统感受野大小，而它们的空间整合特性可分为对比度依赖型（CD）和对比度非依赖型(CID)。在29个CD型的细胞中，17个在低对比度下（10％）下呈现易化整合特性，而在高对比度（80％）下呈现抑制整合特性；另外的12个细胞在高和低对比度下都呈现抑制的整合特性，但是在高对比度下抑制程度明显增加。19个CID型细胞在低和高对比度下呈现出相似的易化或抑制的整合特性，即在两种对比度下测出的空间整合曲线的形状和峰值基本没有改变。用生物胞素作追踪剂我们成功标记了11个CD型和10个CID型细胞。它们的形态学特性表明所有CD型细胞都是锥体细胞，所有CID型细胞都是非锥体细胞；在CID型的细胞中，易化型细胞是有棘星形细胞，抑制型细胞是树突光滑的中间神经元。由此可见，不仅锥体细胞和非锥体细胞空间整合特性上存在普遍差异，而且，有棘非锥体细胞和光滑非锥体细胞在空间整合特性上也存在普遍的差异。 第二部分 在初级视觉皮层，经典感受野（CRF）内刺激引起神经元的反应可以被感受野外区（ERF）的刺激所调制,这种调制效应可以是易化的（F-ERF）或抑制的(I-ERF)，它们在视觉信息加工过程中起不同的作用。关于这两类空间整合神经元的细胞和递质受体方面的机制目前还很不清楚。应用胞内注射生物胞素（bicytin），结合免疫细胞化学技术，我们研究了这两类神经元的形态学和免疫细胞化学方面的特征。研究观察到，这两类神经元在树突和轴突结构以及兴奋性和抑制性受体分布方面都有明显区别。F-ERF神经元大多是锥体细胞，其轴突分布广泛，跨相邻几个功能柱，树突分支复杂，树突棘密度和树突棘头部面积比较大。相反，I-ERF神经元（大多数也是锥体细胞）的轴突主要局限在同一功能柱内，其树突分支较少，树突棘密度和树突棘头部面积比较小。此外，与I-ERF神经元相比，F-ERF神经元在树突和胞体上有更多的兴奋性受体（Glu2/3），以及更少的抑制性受体（GABAA）。由于树突棘是神经元兴奋性突触输入的主要作用位置，而轴突代表了与突触后神经元的输出连接，因此，I-ERF和F-ERF神经元之间的这些输入和输出方面的不同，可能构成这两类神经元具有不同长程调制效应的神经基础。 |
| 英文摘要 | Part Ⅰ Recent studies have reported that the size of the classical receptive field (CRF)and the extent of spatial summation of V1 neurons depend on stimulus contrast. We reexaminedthese properties for 48 V1 neurons in the cat and found that all the cells had a constant CRF size, whereas their spatial summation properties can be contrast-dependent (CD) or contrast independent (CID). Of the 29 CD cells, 17 showed facilitatory summation at low contrast (10%), but suppressive summation at high contrast (80%); the other 12 showed weak suppressive summation at low contrast,whereas the strength of suppression increased significantly at high contrast. The 19 CID cells showed similar facilitative (CIDf) or suppressive (CIDs) summation at low and high contrast, without changes in shape and/or peak location. We successfully labeled 11 CD cells and 10 CID cells with biocytin.The morphological results demonstrated that all the labeled CD cells were pyramidal cells, whereas all labeled CID cells were non-pyramidal cells, in which the CIDf cells were spiny stellates。 Part Ⅱ In the primary visual cortex, activity of neurons evoked by stimuli within the classical receptive field (CRF) can be modulated by stimuli in the extra-receptive field (ERF). This modulating effect can be facilitatory (F-ERF) or inhibitory (I-ERF) that play different roles in visual information processing. Little is known on the cellular and neurotransmitter receptor bases of the two types of long-range interactions. Using in vivo intracellular injection technique, combined with the technique of immunocytochemistry, we have studied the morphological and immunocytochemical features of the F-ERF and I-ERF neurons. Significant differences were found in both the dendrite and axon structures, as well as the density distribution of excitatory and inhibitory neurotransmitter receptors, between the two types of neurons.Neurons with F-ERF were mostly pyramidal cells, having widely distributed axon collaterals covering several cortical columns in the neighborhood;their dendrites have more complex branching covered by densely distributed spines with a larger head. In contrast, the axon collaterals of I-ERF neurons (mostly also pyramidal cells) were restricted within the same cortical column, and the dendrite branching was relatively sparse, with smaller and less spines on it. Moreover, F-ERF neurons have more Glu2/3 receptors and less GABAA receptors on the surface of dendrites and cell body, and the reverse is true for I-ERF neurons. As dendrite spines are the main targets of excitatory synaptic inputs, and the extent of axon collaterals represents the range of output connections with post-synaptic neurons, the differences in the input and output connections between the I-ERF and F-ERF neurons may underlie the distinct long-range modulation effects of the two types of neurons. |
| 语种 | 中文 |
| 公开日期 | 2013-01-05 |
| 页码 | 92 |
| 源URL | [http://ir.sibs.ac.cn/handle/331001/2376]  |
| 专题 | 上海神经科学研究所_神经所(总) |
| 推荐引用方式 GB/T 7714 | Song XM. Morphological bases of spatial summation properties of cat V1 neurons[D]. 上海生命科学研究院. 中国科学院上海生命科学研究院. 2007. |
入库方式： OAI收割
来源：上海神经科学研究所
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