Non-Hebbian type of plasticity in the developing visual cortex.

单眼视觉剥夺（MD）在出生后的早期生活会导致显着的损失皮层反应剥夺的眼睛和回缩的geniculocortical轴突服务剥夺的眼睛（眼优势可塑性）。另一方面，当MD与通过施用GABAA激动剂蝇蕈醇对视觉皮层的药理学抑制组合时，皮层神经元失去对睁开眼睛的反应。此外，活跃的乔木服务一个开放的眼睛选择性地收回，而从剥夺眼睛乔木的分支保持大部分完整，这表明突触前输入和皮层神经元之间的不相关的活动导致传入轴突的修剪。目的：阐明抑制皮层中眼优势可塑性的机制。我们测试了它是否具有类似于正常皮层可塑性的特征，如年龄依赖性。蝇蕈醇治疗成人视皮层并没有引起睁眼反应的丧失，这表明眼优势神经元的可塑性降低。 ...更多信息 受抑制皮质中的CE可塑性仅在发育中的动物中像在正常皮质中一样起作用。进一步的研究表明，眼优势可塑性的时间进程比正常皮层慢。3d的MD对抑制皮层的眼优势可塑性没有诱导作用，而对正常皮层的眼优势可塑性有饱和作用，双眼剥夺（BD）对皮层反应的影响比MD弱得多，并且不诱导传入轴突的回缩。因此，我们研究了是否可以在没有双眼不平衡的情况下诱导抑制皮质中的膝状皮质轴突的回缩。我们分析了形态学的膝状皮质轴突在视觉抑制的视觉皮层的动物与正常的视力和双眼剥夺的动物。在正常视力的动物中，抑制皮层中的轴突乔木表现出强烈的回缩。另一方面，双眼剥夺动物的乔木基本上保持完整。这些结果表明，同源突触的联想机制，而不是异突触输入之间的竞争，可能在眼优势可塑性中发挥重要作用。少

Monocular visual deprivation (MD) in the early postnatal life causes a significant loss of cortical responses to a deprived eye and a retraction of geniculocortical axons serving the deprived eye (ocular dominance plasticity). On the other hand, when MD is combined with a pharmacological inhibition of the visual cortex by administering a GABAA agonist, muscimol, cortical neurons lose their responses to an open eye. Furthermore, active arbors serving an open eye selectively retract, whereas the branches of arbors from a deprived eye remain mostly intact, suggesting that uncorrelated activity between presynaptic inputs and cortical neurons leads to the pruning of afferent axons. To clarify the mechanism of ocular dominance plasticity in the inhibited cortex. we tested whether it has characteristics, such as age-dependency, similar to the plasticity in the normal cortex.Muscimol-treatment of adult visual cortex did not induce a loss of open eye response, suggesting that the ocular dominan … More ce plasticity in the inhibited cortex operates only in developing animals as in the normal cortex. Further study showed that the ocular dominance plasticity proceeds in slower time course than in the normal cortex. Three days MD did not induce the ocular dominance plasticity in the inhibited cortex, while it exerted a saturated effect in the normal cortex.Binocular deprivation (BD) exerts a much weaker effect on cortical responses than MD and does not induce the retraction of afferent axons. Thus, we examined whether the retraction of geniculocortical axons in an inhibited cortex could be induced in the absence of binocular imbalance. We analyzed the morphology of geniculocortical axons in a pharmacologically inhibited visual cortex of animals with normal vision and binocularly deprived animals. In the normal vision animals, the axonal arbors in the inhibited cortex showed robust retraction. On the other hand, the arbors in binocularly deprived animals remained mostly intact. These results suggest that a homosynaptic associative mechanism, rather than a heterosynaptic competition between inputs, may play an important role in the ocular dominance plasticity. Less