Neural circuitry of the parietal lobe

（修订摘要）描述这个试点研究计划是一个概念突破了30年的传统，其特征是单个神经元在顶下小叶的性质，越来越复杂的行为任务和分析，旨在隔离特定的认知功能。 最近的光学成像研究表明，顶下小叶的皮质表面存在多种不同的地形图。最低的分辨率，最强大的是轨道增益场的表示;光流似乎在V1中的视网膜反射中表示方向。该提案从一个新的角度-神经回路-来研究下顶叶的这两种功能。在顶叶皮层中，根本没有直接的证据来解释其感觉和增益场神经元特性是如何产生的。 单个神经元的分子遗传学将被修改，以测量选定的神经元和神经元群体的活性。将使用标准显微镜进行种群测量。双光子扫描显微镜将用于直接比较细胞形态和功能。特定的神经元将被识别和研究许多天，以评估其属性的稳定性。这个概念和研究电路的技术对于联合皮层来说是完全新颖的;在行为动物体内神经元的改良分子遗传学的使用还没有在任何皮层区域中进行。这些研究的影响将是开放行为动物纹状体以外的皮层，以进行电路水平的分析。原则上，成像的分辨率可以扩展到亚细胞元素（如棘）的水平。总之，这个建议是为了了解下顶叶小叶神经元在潜在的神经元回路方面的特性，就像研究人员现在成功地探索初级视觉皮层中的方向调谐和颜色的回路细节一样。虽然技术和概念问题是困难的，但汇集的专门知识适合这项任务。这些研究的成功结果将是一个实质性的进步，允许直接可视化的亚细胞，细胞和电路特性的最高水平的认知功能，如注意力，记忆力，意图和可塑性在下顶叶。

(Revised Abstract) DESCRIPTION This pilot research proposal is a conceptual break from a thirty year tradition characterizing the properties of single neurons in the inferior parietal lobule with increasingly complex behavioral tasks and analyses designed to isolate particular cognitive functions. Recent optical imaging studies have revealed the presence of multiple different topographic maps across the cortical surface of the inferior parietal lobule. The lowest resolution, and most robust is a representation of orbital gain fields; optic flow appears to be represented within this much as orientation is within retinotopy in V1. The proposal examines these two functions in inferior parietal lobe from a novel perspective- the neural circuit. There is simply no direct evidence in parietal cortex explaining how its sensory and gain field neuronal properties are generated. The molecular genetics of single neurons will be modified to measure the activity of selected neurons and populations of neurons. Standard microscopy will be used for population measures. Two-photon scanning microscopy will be use to directly compare cellular morphology and function. Specific neurons will be identified and studied over many days to assess the stability of their properties. This concept and the techniques for studying the circuitry is completely novel for association cortex; the use of modified molecular genetics of neurons in vivo in behaving animals has not been performed in any cortical area. The impact of these studies will be to open up cortex beyond striate in the behaving animal to circuit level analysis. In principle, the resolution of imaging can be extended to the level of the sub-cellular elements such as spines. In summary, this proposal is designed to understand properties of inferior parietal lobule neurons in terms of underlying neuronal circuits, much as investigators are now successfully exploring the circuit details of orientation tuning and color in primary visual cortex. Although the technical and conceptual issues are difficult, the expertise assembled is appropriate to the task. The successful outcome of these studies will be a substantial advance permitting direct visualization of the sub-cellular, cellular and circuit properties underlying the highest level cognitive functions such as attention, memory, intention and plasticity in the inferior parietal lobule.