SPINE MOTILITY AND VISUAL PLASTICITY

描述(摘自申请者的摘要)：树突棘是主要的 哺乳动物中枢神经系统中突触输入的部位，传统上一直是 被认为是稳定的结构。尽管如此，正如弗朗西斯最初建议的那样 克里克和最近我们小组和其他人的数据证实，脊椎是 在分离的培养物和脑片中都有运动能力。脊柱的运动性是 以动作为基础，似乎是神经元固有的。因为 脊椎在皮质环路中的重要性，脊柱的运动性可能 可能会对大脑皮层的发育和功能产生重大影响。 在我们之前的工作中，我们发现小鼠皮质中的脊柱运动 在出生后时代下调，预示着关键时期的结束 单眼剥夺期。虽然小学阶段的关键时期 视觉皮层已被广泛研究了几十年，至今仍未见报道。 目前尚不清楚是什么因素终止了这一进程。基于这种相关性，我们假设 关键时期的结束是由于经济增长缺乏动力 脊椎。 我们希望结合基因枪绿色荧光蛋白详细检验这一假说。 转基因、双光子成像、图像去卷积和电子显微镜 小鼠初级视皮层和活体脑片中脊椎的研究 成像、剥夺和药理实验。第一个目标将集中在 在描述Mouser V1B和Mouser V1B不同皮质层的运动性时， 在超微结构水平上重建之前成像的脊椎。 在序列重建中找到相同的脊椎的能力 双光子延时电影将使我们能够以前所未有的细节来研究 运动能力的存在与类型之间是否存在相关性 以及突触前终末的存在和类型。第二个目标将寻求 确定调节运动的细胞机制，特别强调 关于Rho家族小TGPase的下游靶标和在 考察突触活动在这一过程中的作用。第三个目标 将直接检验脊柱运动在关键时期是否起到因果作用， 通过检查它是否存在于体内，并通过分析 在单眼剥夺范式中阻止它。 这些研究将阐明结构塑性在 视皮层的发育。此外，它们还将帮助识别 单眼剥夺的皮质后果，可能是影响的基础 弱视和斜视，以及帮助设计旨在 在弥补这些赤字方面。更全面地了解 视皮层的发育也将改善敏锐度的测量， 语前儿童和幼儿的对比敏感度和色觉敏感度 视觉病理的早期诊断。

DESCRIPTION (Adapted from applicant's abstract): Dendritic spines are the major sites of synaptic input in the mammalian CNS and have been traditionally been considered stable structures. Nevertheless, as initially suggested by Francis Crick and confirmed recently by data from our group and by others, spines are motile in both dissociated cultures and in brain slices. Spine motility is action-based and appears to be intrinsic to the neuron. Because of the importance of spines in the cortical circuit, spine motility could have potentially, major consequences in the development and function of the cortex. In our previous work we discovered that spine motility in mouse cortex is down-regulated during the postnatal ages that herald the end of the critical period for monocular deprivation. Although the critical period in primary visual cortex has been studied extensively for many decades, it is still unclear what factors terminate it. Based on this correlation we hypothesized that the end of the critical period is due to the lack of motility of the spines. We want to examine this hypothesis in detail combining gene-gun GFP transfection, two-photon imaging, image deconvolution and electron microscopy of spines in brain slices from mouse primary visual cortex, as well as in vivo imaging, deprivation and pharmacological experiments. The first aim will focus in characterizing the motility in different cortical layers in mouser V1B and in reconstructing at the ultrastructural level the previously imaged spines. The ability of finding in serial reconstructions the same spines imaged in two-photon time-lapse movies will allow us to examine with unprecedented detail whether there are any correlations between the presence and type of motility and the presence and type of presynaptic terminal. The second aim will seek to identify the cellular mechanisms mediating the motility, with special emphasis on the downstream targets of the Rho family of small TGPases and in the examination of the role of synaptic activity in this process. The third aim will directly test if spine motility lays a causal role in the critical period, by examining whether it exists in vivo and by analyzing the consequences of blocking it in the monocular deprivation paradigm. These studies will shed light on the role of structural plasticity in the development of the visual cortex. In addition, they will help discern the cortical consequences of monocular deprivation, effects which may underlie amblyopia and strabismus, as well as help design therapeutic strategies aimed at compensating for these deficits. A more complete understanding of the development of visual cortex will also improve the measurement of acuity, contrast sensitivity and chromatic sensitivity of preverbal children and in early diagnosis of visual pathologies.