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Morpho-functional study of converging axonal projections in the auditory cortex

听觉皮层会聚轴突投射的形态功能研究

基本信息

批准号：
11680743
负责人：
OJIMA Hisayuki
金额：
$ 1.86万
依托单位：
The Institute of Physical and Chemical Research (2000)Toho University (1999)
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1999
资助国家：
日本
起止时间：
1999 至 2000
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-11680743/
关键词：
auditory field axon convergent projection tonotopic map horizontal connection local circuit anterograde tracer cat 聴覚大脳皮質 1次聴覚野局所結合軸索投射聴覚皮質周波数マッピング

项目摘要

A small population of cortical neurons project local, short-distance axons. This projection is not diffusely or homogeneously distributed over the cortical region, but forms patches of terminal axons at several hundred μm distant from injection site, in addition to a dense plexus of axons around injection site. How do patchy organizations of terminal axons originating from different cortical sites located closely but representing different sensory features interact each other? Does a particular cortical site receive information only from one cortical site or from multiple other cortical sites? In the latter case, there must take place some convergence of information. Revealing the pattern of cortical convergence seems to be crucial to understanding some basic mechanism of cerebral cortex.Under aneasthetic condition, the auditory corex of cats were mapped using the conventional electrophysiology by applying pure tones to contralateral ear. Then two tracers, phaseolus vulgaris leukoagglu … More tinin (PHA-L) and biotinylated dextran amine (BDA), were ionotophoretically injected in close proximity, separating at about 500 to 1000 μm. Injection sites covered cortical area of about 300-500 μm in diameter. After cutting tangential sections from the auditory cortex, PHA-L and BDA were reacted for different colors ; purple to black and brown, respectively. Differentially labeled axons originating from different tracer injection sites were scanned for their distribution over the auditory cortex. Areas which contain only one of the two tracer-labeled axons and areas which contain both tracer-labeled axons were identified. Injections into the center part of the primary auditory cortex (Al) resulted in patches of labeled axon distributing medial and lateral to the injection site, while injections into more posteriorly located part resulted in patches distributing more widely, including anterior and posterior in addition to medial and posterior to injection site. In both injection cases, overlapping distribution of PHA-L-labeled axons and BDA-labeled axons was found mainly at the most distal patches medially and laterally. Since a systematic tonotopic map of frequency is formed across cat Al, the results indicate that local circuits related to high-frequency and low-frequency processing take different form of connection. Less

一小部分皮质神经元投射出局部的短距离轴突。这种投射不是弥漫或均匀地分布在皮质区，而是在距离注射部位几百μm处形成成片的终末轴突，并在注射部位周围形成致密的轴突丛。来自不同皮质位置但代表不同感觉特征的末梢轴突的斑块组织是如何相互作用的？特定的皮质部位是只从一个皮质部位接收信息，还是从多个其他皮质部位接收信息？在后一种情况下，必须进行某种程度的信息汇聚。揭示大脑皮层会聚的模式对于了解大脑皮层的一些基本机制似乎是至关重要的。在听觉失灵的情况下，猫的听觉中枢通过对侧耳施加纯音进行常规电生理学的标测。然后两种示踪剂，普通菜豆，白蛋白…更多的TiNiN(PHA-L)和生物素化葡聚糖胺(BDA)被近距离离子电泳法注射，间隔约500~1000μm，注射部位覆盖皮质面积约300~500μm。在从听觉皮质切下切下的切面后，PHA-L和BDA被分别反应为不同的颜色，从紫色到黑色和棕色。来自不同示踪剂注射部位的差异标记轴突被扫描，以寻找它们在听觉皮质上的分布。识别出只包含两个示踪剂标记轴突中的一个的区域和包含两个示踪剂标记轴突的区域。注射到初级听觉皮质中央部，标记轴突的斑块分布在注射部位的内侧和外侧，而注射到位置更靠后的部分，标记轴突的分布范围更广，除注射部位的内侧和后方外，还包括前部和后部。在两种注射情况下，PHA-L标记的轴突和BDA标记的轴突主要重叠分布在最远端的内侧和外侧斑块。由于在CAT A1上形成了系统的频率调位图，因此结果表明，与高频和低频加工有关的局部电路采取不同的连接形式。较少