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A study on synaptic mechanisms in the retinal neural network

视网膜神经网络突触机制的研究

基本信息

批准号：
06044181
负责人：
YASUI Syozo
金额：
$ 6.98万
依托单位：
Kyushu Institute of Technology
依托单位国家：
日本
项目类别：
Grant-in-Aid for international Scientific Research
财政年份：
1994
资助国家：
日本
起止时间：
1994 至 1996
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-06044181/
关键词：
retina horizontal cell synapse plasticity glutamate neural network NO antibody

项目摘要

This research has revolved aroud the vertebrate retina that has long been a favorite object of neuroscience research partly because of the same morphogenic origin as the brain. In particular, we have been concerned with the outer-retinal neural circuitry that involves photoreceptors and such second-order neurons as horizontal and bipolar cells. One of the main projects has produced the following findings regarding the synaptic transmission from cone photoreceptors to H1 horizontal cells (H1 HCs) in the cyprinid fish. Thus, the conventional notion of the cone signal being processed by the kanate-type excitatory synapse is correct only for long-wavelength visual signals, and the synapse mediating the short-wavelength transmission operates with a post-synaptic glutamate receptor mechanism which is polarity-reversing, conductance-decreasing and APB-sensitive, thus most likely mGluR6. Moreover, activation of this receptor mechanism requires either light adaptation (high SNR) or nitric oxide (NO). These properties are found to contribute to adaptation-dependent modulation of the spectral sensitivity as well as of the receptive field of H1 HCs. The notion of NO acting as light-adaptation signal for neural plasticity in the retina is found to be also appropriate for EM-level morphological changes in the post-synaptic invagination of horizontal cells dendrites These physiological, . Pharmacological and anatical findings have been combined with computational studies using neural network models, to help developing a new type of image processors which are adaptive to the visual environmental factors such as SNR and color changes. A prototype vision chip was designed and fabricated in this connection.

这项研究一直围绕着脊椎动物的视网膜，这一直是神经科学研究的最爱对象，部分原因是与大脑相同的形态发生起源。特别是，我们一直关注的外视网膜神经回路，涉及光感受器和这样的二级神经元的水平和双极细胞。其中一个主要的项目已经产生了以下关于从视锥光感受器到鲤科鱼类H1水平细胞（H1 HCs）的突触传递的发现。因此，由kanate型兴奋性突触处理视锥信号的传统概念仅对长波长视觉信号是正确的，并且介导短波长传输的突触以突触后谷氨酸受体机制操作，该机制是极性反转的、电导降低的和APB敏感的，因此最可能是mGluR6。此外，这种受体机制的激活需要光适应（高SNR）或一氧化氮（NO）。这些属性被发现有助于适应依赖调制的光谱灵敏度以及H1 HC的感受野。NO作为视网膜神经可塑性的光适应信号的概念被发现也适用于水平细胞树突突触后内陷的EM水平形态学变化。药理学和解剖学的研究结果已经与使用神经网络模型的计算研究相结合，以帮助开发一种新型的图像处理器，该图像处理器能够适应视觉环境因素，如SNR和颜色变化。在此基础上设计并制作了一个原型视觉芯片。