NEURAL MECHANISMS OF VISION

各种实验表明，谷氨酸受体很重要。 在视觉皮质中依赖感觉的可塑性。信号用于 依赖感觉的可塑性通过电传递到大脑皮层 活动，在大脑皮层释放谷氨酸。谷氨酸能激活 NMDA、AMPA/海人藻酸和代谢性谷氨酸受体。它的重要性 有证据表明：(I)NMDA的拮抗剂 受体降低可塑性；(Ii)NMDA受体在 感官可塑性临界期的高峰；(三) NMDA受体在视觉反应中的功能贡献 在关键时期减少；以及(Iv)在黑暗中养育 推迟NMDA对视觉反应贡献的变化， 就像它推迟了其他依赖感觉的可塑性事件一样。这 提案将评估NMDA的功能所依据的机制 感觉依赖临界期受体的变化 可塑性。对代谢性谷氨酸受体知之甚少，而且 他们的影响力在关键时期发生了怎样的变化。这项建议 将评估代谢性谷氨酸受体的作用 对视觉反应的影响，以及如何在 发展。代谢型谷氨酸受体影响K+通道、钙离子通道 渠道和第二信使。该提案还将考验这一行动 代谢性谷氨酸受体在第二信使阵营：哪一个 代谢性受体激活它，无论这种激活是在 关键期的时间进程，以及激活如何受到影响 在黑暗中成长。

A variety of experiments suggest that glutamate receptors are important in sensory-dependent plasticity in the visual cortex. The signals for sensory-dependent plasticity are carried to the cortex by electrical activity, which releases glutamate in the cortex. Glutamate activates NMDA, AMPA/kainate and metabotropic glutamate receptors. The importance of NMDA receptors is suggested by evidence that (i) antagonists to NMDA receptors reduce plasticity; (ii) NMDA receptors are most abundant at the peak of the critical period for sensory-dependent plasticity; (iii) the functional contribution of NMDA receptors to the visual response is reduced during the critical period; and (iv) rearing in the dark postpones the change in the NMDA contribution to the visual response, just as it postpones other events in sensory-dependent plasticity. This proposal will evaluate the mechanisms by which the function of NMDA receptors changes during the critical period for sensory-dependent plasticity. Less is known about metabotropic glutamate receptors, and how their influence changes during the critical period. This proposal will evaluate the contribution that metabotropic glutamate receptors make to the visual response, and how this is altered during development. Metabotropic glutamate receptors affect K+ channels, Ca++ channels, and second messengers. The proposal will also test the action of metabotropic glutamate receptors on the second messenger cAMP: which metabotropic receptor activates it, whether the activation follows the time course of the critical period, and how the activation is affected by rearing in the dark.