Optogenetic dissection of hippocampal circuitry underlying Alzheimers disease

7.项目总结/摘要 识别学习和记忆的基础电路是至关重要的， 不仅是记忆的机制，还有这些机制在记忆中是如何失调的， 疾病，如阿尔茨海默病（AD）。人类和啮齿动物病变研究表明， 海马（HPC）在长期记忆中的作用，特别是CA 1亚区。CA 1优先激活， 记忆必须保持很长一段时间，研究表明，大部分CA 1 神经元在重复暴露于相同环境中时被重新激活。然而，以前的研究没有 能够评估单个CA 1神经元在学习和记忆中的长期（> 1个月）参与， 或在AD中，因为所有先前的转基因品系都缺乏不可磨灭的标记。在这项建议中， 个体CA 1神经元对经验的编码和对相应记忆的检索将 通过利用转基因系ArcCreERT 2小鼠进行研究。这条鼠标线可以让不可磨灭的 标记表达立即早期基因Arc/Arg3.1的细胞，并允许比较 这些细胞在体验编码过程中被激活，而在体验提取过程中被激活。 对应的记忆。结合光遗传学报告细胞系，这些研究将评估长- CA 1神经元参与记忆编码和提取。为了充分描述CA 1的作用， 在记忆神经元中，我们将选择性地表达蓝光激活的阳离子通道通道视紫红质-2 （ChR 2）或黄光激活的外向质子泵古紫质（Arch）在CA 1群体中的表达 神经元编码利用光遗传学，我们将检验CA 1的亚群 神经元对于恢复相应的长期记忆是足够和必要的。其次， 通过使用三重转基因设计，将在AD小鼠中描绘记忆编码和提取中的CA 1。 在对照组和AD组中，最初在编码过程中标记的CA 1神经元可以被光遗传学调节， 小鼠在体内，我们将检验光遗传学刺激或抑制CA 1锥体神经元 在记忆提取过程中将改善AD小鼠的记忆表达。最后，光遗传学操作 将用于在对照和AD小鼠中模拟深部脑刺激样方案，以改善 AD小鼠的整体细胞功能、细胞存活和记忆恢复。

7. PROJECT SUMMARY / ABSTRACT It is of utmost importance to identify the circuits underlying learning and memory in order to understand not only the mechanisms of memory but also the how these mechanisms become dysregulated in memory disorders, such as Alzheimer's disease (AD). Human and rodent lesion studies have suggested a role for the hippocampus (HPC) in long-term memory, specifically the subregion CA1. CA1 is preferentially activated when a memory must be retained over a long period of time, and studies have shown that a large proportion of CA1 neurons are reactivated in repeated exposures to the same environment. However, no previous studies have been able to assess the long-term (> 1 month) involvement of individual CA1 neurons in learning and memory, or in AD, since all previous transgenic lines have lacked an indelible label. In this proposal, the contribution of individual CA1 neurons to the encoding of an experience and to the retrieval of a corresponding memory will be investigated by utilizing a transgenic line, the ArcCreERT2 mice. This mouse line allows for the indelible labeling of cells expressing the immediate early gene Arc/Arg3.1 and allows for a comparison between the cells that are activated during the encoding of an experience and those that are activated during the retrieval of the corresponding memory. In combination with optogenetic reporter lines, these studies will assess the long- term involvement of CA1 neurons in memory encoding and retrieval. To fully characterize the role of CA1 neurons in memory, we will selectively express the blue light activated cation channel channelrhodopsin-2 (ChR2) or the yellow light activated outward proton pump archaerhodopsin (Arch) in populations of CA1 neurons during encoding. Using optogenetics, we will then test the hypothesis that a subpopulation of CA1 neurons is sufficient and necessary for the retrieval of a corresponding long-term memory. Next, the role of CA1 in memory encoding and retrieval will be delineated in AD mice by utilizing a triple transgenic design in which CA1 neurons, initially labeled during encoding, can be optogenetically modulated in control and AD mice. In vivo, we will test the hypothesis that optogenetic stimulation or inhibition of CA1 pyramidal neurons during memory retrieval will improve expression of a memory in AD mice. Finally, optogenetic manipulations will be used in order to mimic a deep brain stimulation-like protocol in control and AD mice in order to improve overall cellular function, cell survival, and memory retrieval in AD mice.