A role of afferent activity in the maturation of thalamocortical connections of visual system

传入活动在视觉系统丘脑皮层连接成熟中的作用

基本信息

批准号：
12680795
负责人：
HATA Yoshio
金额：
$ 1.98万
依托单位：
Osaka University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2000
资助国家：
日本
起止时间：
2000 至 2001
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-12680795/
关键词：
VISUAL CORTEX OCULAR DOMINANCE VISUAL DEPRIVATION DEVELOPMENT CAT LONG-TERM POTENTIATION

项目摘要

Binocular visual responsiveness of neurons in visual cortex of cats, monkeys and other mammals including humans can be changed by monocular visual deprivation in the critical period of postnatal development, one of the best-known examples of experience-dependent modification of brain function.It is hypothesized that afferents from each eye compete with one another for synaptic connections with cortical neurons so that less active afferents from the deprived eye fail to maintain the connections, i.e., balance between activities of both afferents is important to determine the fate of each eye-specific pathway.This synaptic competition hypothesis has been supported by various types of deprivation experiments in kittens. If such a competition hypothesis is valid, then an increase in inputs from one eye instead of decrease due to deprivation should also change binocular responsiveness of cortical neurons. Otherwise the deprivation-induced change might be due to "disuse" weakening of responsiveness.However, the hypothesis has never been tested with such a monocular activation paradigm. In the present project, we activated one of the optic nerves by electrical stimulation in behaving kittens for 2 days, and found that such a chronic, monocular activation induced a shift in ocular dominance of visual responses of cortical neurons.

猫、猴子和包括人类在内的其他哺乳动物的视觉皮层神经元的双眼视觉反应可以在出生后发育的关键时期通过单眼视觉剥夺而改变，这是大脑功能依赖于经验的改变的最著名的例子之一。假设来自每只眼睛的传入神经相互竞争与皮质神经元的突触连接，因此来自被剥夺的眼睛的不太活跃的传入神经无法维持连接，即，两个传入神经活动之间的平衡对于决定每个眼睛特定通路的命运。这种突触竞争假说已得到小猫各种类型的剥夺实验的支持。如果这样的竞争假设是有效的，那么一只眼睛的输入增加而不是由于剥夺而减少，也应该改变皮层神经元的双眼反应性。否则，剥夺引起的变化可能是由于“废弃”反应能力的减弱所致。然而，该假设从未用这样的单眼激活范式进行过检验。在本项目中，我们通过电刺激行为小猫两天来激活其中一根视神经，发现这种慢性单眼激活会导致皮层神经元视觉反应的眼部优势发生变化。