Mechanisms for self-organization of cerebral cortical circuitry

大脑皮层回路的自组织机制

• 批准号: 05404086
• 负责人: TOYAMA Keisuke
• 金额: $ 18.88万
• 依托单位: Kyoto Pref. Univ. of Med.
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (A)
• 财政年份: 1993
• 资助国家: 日本
• 起止时间: 1993 至 1996
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-05404086/
• 关键词: Self-organization,; Development,; Visual cortex,; Plasticity,; Long term potentiation,; Laminar structures,; Gene transcription,; Coculture preparation; コバリアンス学習; 共培養標本

How is the cortical circuitry constructed (self-organized) by interaction between gene and learning mechanisms? This has been one of the central problems in the developmental neurobiology. This study revealed that the development of the laminar structures in the visual cortex (VC) specifying what targets neurons in a particular layr are connected to, totally depend on the gene mechanisms. All laminar structures in the normal VC are reproduced in the coculture preparations where a block of the lateral geniculate nucleus and a VC slice of infant rats were cultured together.Another finding of the present study is demonstration of two types of long term potentiation (LTP) in rat VC,i. e., 1) slow LTP (sLTP) which had a slow time course and was only induced in infant rats, and 2) fast LTP (fLTP) which had a fast time course and was induced both in infant and adult rats. Induction of sLTP depended on Ca entry through voltage gated Ca channels, gene transcription as well as protein synthesis and was expressed in the geniculo-cortical synapses, while that of fLTP depended on Ca entry through NMDA channels and was expressed in the axon collateral synapses of the cortical efferents. These observations indicate that sLTP underlies the developmental plasticity for formation of the columnar structures in infant VC,while fLTP is the basis for the plasticity in adult VC.

基因和学习机制之间的相互作用是如何构建（自组织）大脑皮层回路的？这一直是发育神经生物学的核心问题之一。这项研究表明，在视觉皮层（VC）的层状结构的发展，指定在特定层中的目标神经元连接到，完全取决于基因机制。将大鼠外侧膝状体与VC切片共培养，可再现正常VC的所有层状结构，并证实VC存在两种长时程增强（LTP），即LTP和LTP。例如，1)慢LTP（sLTP），其具有缓慢的时程，并且仅在幼年大鼠中诱导;以及2）快LTP（fLTP），其具有快速的时程，并且在幼年和成年大鼠中均诱导。sLTP的诱导依赖于电压门控Ca通道的Ca内流、基因转录以及蛋白质合成，并在膝状体-皮质突触中表达; fLTP的诱导依赖于NMDA通道的Ca内流，并在皮质传出神经的轴突侧支突触中表达。这些观察结果表明，sLTP的基础上的发育可塑性形成的柱状结构在婴儿VC，而fLTP是可塑性在成人VC的基础。

项目成果

Toyama, K., Yamamoto, N., and Tanifuji, M.: "Pre-and postnatal mechanisms for formation of visual cortical circuitry" Perception, memory and emotion : frontiers in neuroscience ed. by Ono, T., McNaoughton, B.L., Molotchnikoff, S.and Nishijo, H., Pergamon,

Toyama, K.、Yamamoto, N. 和 Tanifuji, M.：“视觉皮层电路形成的产前和产后机制”感知、记忆和情感：神经科学的前沿编辑。

Kurotani,T.: "Development of neural connections between visual cortex and transplanted lateral geniculate nucleus in rats." Dev.Brain Res.71. 151-168 (1993)

Kurotani,T.：“大鼠视觉皮层和移植的外侧膝状核之间神经连接的发育。”

Toyama,K.: "Pre-and postnatal structures in the rat cerebral cortical circuitry." Basic Neurosci.in Invertebrates,ed.by Kidokoro et al.,Japan Scientific Society Press. 333-339 (1996)

Toyama, K.：“大鼠大脑皮层回路的产前和产后结构。”

Kurotani, T., Higashi, S., Inokawa, H.and Toyama, K.: "Protein and RNA synthesis-dependent and-independent LTPs in developing rat visual cortex." Neuroreport. (in press).

Kurotani, T.、Higashi, S.、Inokawa, H. 和 Toyama, K.：“发育中的大鼠视觉皮层中蛋白质和 RNA 合成依赖和独立的 LTP。”

Yamamoto, N.: "Stop and branch signals for geniculocortical connections : A time-lapse study with a fluorescent dye in organotypic cocultures" J. Neurosci.(in press).

Yamamoto, N.：“膝皮质连接的停止和分支信号：器官共培养中荧光染料的延时研究”J. Neurosci.（正在出版）。