Regulation of Anatomical Plasticity and Perceptual Learning by NgR1

描述（由申请人提供）：新的感觉体验和改善的运动表现改变了大脑皮层的突触结构连通性，但这种解剖可塑性对感知学习的功能贡献尚不清楚。最近，在体内反复成像神经元结构的新兴技术将注意力集中在树突棘的重塑上，树突棘是学习的潜在基础。然而，解决脊柱重塑与学习之间关系的一个主要障碍是确定脊柱动力学是否特定于皮质区域、神经元身份和学习任务。由于须的地形表征和须使用的可控制、可量化的性质，体感觉皮层（桶状皮质）中的桶状场一直是检查感官体验期间脊柱重塑的一个受欢迎的系统。间隙穿越任务是一项自动化的、定量的感知学习任务，它依赖于晶须对两个平台之间间隙的检测。这些实验将桶状皮质树突棘的慢性体内成像与感知学习任务相结合，以研究脊柱重塑的速度是否以及如何指定感知学习的速度。为了验证脊柱重塑的速度报告感知学习的速度这一假设，随后的联合成像和学习实验利用了nogo-66受体（NgR1）突变小鼠的表型，这些小鼠学习这项任务的速度更快。NgR1是一种神经元蛋白，可调节损伤和完整中枢神经系统的可塑性。NgR1突变体在脊髓损伤和中风后恢复较好；成人NgR1突变体也表现出一种通常局限于发育关键期的视觉可塑性。NgR1如何调节脊柱重塑和知觉学习不仅可以提高对解剖可塑性如何促进学习的理解，还可以揭示该受体在损伤后和发育过程中控制可塑性的保守机制。

DESCRIPTION (provided by applicant): Novel sensory experience and improved motor performance modify structural synaptic connectivity in the cerebral cortex, yet the functional contribution of this anatomical plasticity to perceptual learning is unclear. Recently, emerging techniques for repeatedly imaging neuronal structures in vivo has focused attention upon the remodeling of dendritic spines as a potential substrate for learning. However, a major obstacle to resolving the relationship between spine remodeling and learning is determining if spine dynamics are specific to cortical region, neuronal identity and learning task. The barrel field in somatosensory cortex (barrel cortex) has been a favored system for examining spine remodeling during sensory experience due to the topographical representation of whiskers and controlled, quantifiable nature of whisker use. The gap crossing task is an automated, quantitative perceptual learning task that relies on detection of a gap between two platforms by the whiskers. These experiments combine chronic in vivo imaging of dendritic spines in barrel cortex with this perceptual learning task to investigate if and how the rate of spine remodeling may specify the rate of perceptual learning. To test the hypothesis that the rate of spine remodeling reports the rate of perceptual learning, subsequent combined imaging and learning experiments exploit the phenotype of nogo-66 receptor (NgR1) mutant mice that learn this task faster. NgR1 is a neuronal protein that regulates plasticity in both the injured and intact central nervous system. NgR1 mutants recover better from spinal cord injury and stroke; adult NgR1 mutants also display a form of visual plasticity normally confined to a developmental critical period. How NgR1 regulates both spine remodeling and perceptual learning may improve not only understanding of how anatomical plasticity contributes to learning, but may reveal conserved mechanisms by which this receptor governs plasticity after injury and during development as well.