FUNCTIONAL PLASTICITY OF THE DEVELOPING NERVOUS SYSTEM

中枢神经系统（CNS）的许多部分都是高度发达的。 在个体发育过程中相互依赖。 因此，在功能上具有重要意义 一个基因座的发育异常的影响可能会级联， 神经系统的遥远部分。 具体来说，早期病变的 发展中的CNS可导致永久性、新的 各种神经结构之间的联系。 这种连接可以 有助于保留通常会失去的神经功能 在成熟CNS中的类似病变或新连接后， 可能会功能失调 仓鼠和其他动物发育中的视觉系统的某些病变 物种诱导形成新的视网膜投射到听觉 或躯体感觉系统。 我们用这些新的神经回路 研究控制各种特征发展的机制， 哺乳动物的视觉系统 我们还证明了， 和生理组织的新的神经回路类似，在 他们的许多基本特征，那些正常的视觉系统。 最有趣的是，我们发现躯体感觉中的单个神经元 具有新的视网膜投射的经尿道手术的仓鼠的皮质， 躯体感觉系统具有视觉特性， 在数量上类似于正常人视觉皮层中的神经元 仓鼠 这些数据提出了两个非排他性的假设-丘脑 在不同的原发灶中， 感觉系统以类似的方式处理它们的输入， 在发展时期，这些结构在某种程度上是等势的 并根据其输入进行区分。 我们的研究结果表明，新的神经通路可能能够介导 视觉引导行为的某些方面，即，仓鼠可以 和他们一起“看”。 在目前的研究中，我们建议：a）测试 新途径在行为水平上的功能，B）鉴定 一些输出路径，通过这些输出路径，新颖的电路可能具有它们的 行为效应和c）研究这些输出的发展 途径。 我们的发现对心理健康、神经系统 疾病和发育神经学，因为它们有助于1） 理解感知和认知的神经机制，2） 了解感觉皮层的功能组织， 丘脑核团，3）了解正常和病理性神经 发展和4）外科手术范例的发展 修复大脑。

The numerous parts of the central nervous system (CNS) are highly interdependent during ontogeny. Consequently, functionally significant effects of a developmental aberration at one locus may be cascaded to distant parts of the nervous system. Specifically, early lesions of the developing CNS can result in the formation of permanent, novel connections between various neural structures. Such connections can contribute to a sparing of neural function that would normally be lost following comparable lesions in the mature CNS, or the novel connections can be dysfunctional. Certain lesions of the developing visual system in hamsters and other species induce the formation of novel retinal projections to the auditory or somatosensory systems. We have used these novel neural circuits to study the mechanisms controlling the development of various features of the mammalian visual system. We also demonstrated that the anatomical and physiological organization of the novel neural circuits resemble, in many of their essential features, those of the normal visual system. Most interestingly, we showed that single neurons in the somatosensory cortex of neonatally operated hamsters with novel retinal projections to the somatosensory system have visual properties that qualitatively and quantitatively resemble those of neurons in the visual cortex of normal hamsters. These data raise two non-exclusive hypotheses - that thalamic nuclei or cortical areas at corresponding levels in different primary sensory systems process their inputs in similar ways or that during some developmental period, these structures are, to some extent, equipotential and differentiate as a function of their inputs. Our results suggest that the novel neural pathways may be able to mediate certain aspects of visually guided behavior, i.e., that the hamsters can "see" with them. In the present studies, we propose: a) to test the function of the novel pathways at the behavioral level, b) to identify some output pathways by which the novel circuits might have their behavioral effects and c) to study the development of these output pathways. Our findings are significant for mental health, neurological disease and developmental neurology in that they contribute 1) to understanding the neural mechanisms of perception and cognition, 2) to understanding the functional organization of sensory cortices and thalamic nuclei, 3) to understanding normal and pathological neural development and 4) to the development of paradigms for the surgical repair of the brain.