Optogenetic dissection of dentate gyrus circuitry underlying anxiety

职位描述(申请人提供)：我的职业目标是培养研究生、本科生和医学生，并独立领导一个研究小组，调查动机和情绪相关行为背后的神经回路，最终将这一见解用于翻译研究。为了实现这一目标，我提出了一个项目，通过研究齿状回(DG)回路是如何促进焦虑样行为的，为我提供了一个重要的培训。具体地说，我将研究DG颗粒细胞(GC)的发育来源或区域位置是否决定了它们对情绪行为的贡献。为了测试这一点，我将使用 控制成熟和成体出生的背部颗粒细胞活动的光遗传技术 或腹侧DG，以确定它们对焦虑样行为的相对贡献。我的主要专长是老鼠行为、分子生物学和老鼠遗传学。我的职业发展计划将在此基础上扩展，为我提供基本的膜片钳电生理学、活体电生理学和活体行为过程中的光遗传神经调节方面的培训。由于我的职业目标是领导一个研究小组，研究情感行为背后的回路，以及它们在疾病状态下是如何出错的，这些技能不仅是必需的，而且对我成功领导一个全面、独立的研究生涯至关重要。此外，由于我之前的重点是基础研究，我建议扩大我在翻译神经科学方面的培训，以便我可以应用我的研究来成功地与临床医生合作。研究项目确定焦虑和抑郁背后的回路机制对于治疗精神疾病至关重要。在这项提案中，我将研究齿状回(DG)是如何促进焦虑样行为的。虽然经典的研究是因为它在 空间学习，有很大的支持DG在情绪行为中的作用，但 这一现象的机制尚不清楚。一种潜在的机制来自于观察到情绪状态可以影响位于成人DG中的干细胞产生新的颗粒细胞(GC)。此外，最近的研究表明，海马体沿着其背腹轴在功能上是分开的，通过其腹极影响焦虑样行为。这表明，GC是一个功能不同的神经元池，局部由它们的发育来源决定，局部由它们在海马背腹轴上的位置决定。为了测试这些可能性，我们在成熟和成年出生的GC群体中选择性地表达了蓝色光激活的阳离子通道通道视紫红质-2(ChR2)和黄色光激活的氯泵卤视紫红质(eNpHR3.0)。利用体外局部电路图，我们将检验成年出生的GC调节DG输出的假设。在体内，我们将检验这一假设，即光刺激或抑制腹侧DG中的GC优先影响焦虑样行为，而背侧DG影响空间学习。最后，我们将剖析成年出生的GC对焦虑样行为的优先贡献。

DESCRIPTION (provided by applicant): My career goal is to train graduate, undergraduate, and medical students, and independently lead a research group that investigates the neural circuitry underlying motivated and mood-related behavior to eventually use this insight for translational research. To achieve this goal, I am proposing a project that provides me with significant training by examining how the dentate gyrus (DG) circuit contributes to anxiety-like behavior. Specifically, I will examine whether the developmental origin or regional position of DG granule cells (GCs) dictates their contribution to emotional behavior. To test this, I will use optogenetic techniques to control the activity of mature and adult-born granule cells in the dorsal or ventral DG to determine their relative contribution to anxiety-like behavior. My primary expertise is in mouse behavior, molecular biology and mouse genetics. My career development plan will expand on this by providing me essential training in patch clamp electrophysiology, in vivo electrophysiology, and in vivo optogenetic neuromodulation during behavior. As my career goal is to lead a research group examining the circuits that underlie affective behavior, and how they go wrong in disease states, these skills are not only required, but also essential to my success in leading a well-rounded, independent research career. In addition, as my previous focus has been on basic research, I have proposed to expand my training in translational neuroscience, so that I may apply my research to successfully collaborate with clinicians. Research Project Identifying the circuit mechanisms that underlie anxiety and depression is of utmost importance for treating psychiatric illness. In this proposal, I will examine how the dentate gyrus (DG) contributes to anxiety-like behavior. While classically studied for its role in spatial learning, there is significant support for a role for the DG in emotional behavior, but the mechanism for this remains unknown. A potential mechanism derives from the observation that emotional state can influence the production of new granule cells (GCs) from stem cells located in the adult DG. In addition, recent studies suggest the hippocampus is functionally segregated along its dorsal-ventral axis, influencing anxiety-like behavior through its ventral pole. This would suggest that GCs represent a functionally heterogeneous pool of neurons determined locally by their developmental origin and regionally by their position along the dorsal-ventral axi of the hippocampus. To test these possibilities, we have selectively expressed the blue light activated cation channel channelrhodopsin-2 (ChR2) and the yellow light activated chloride pump halorhodopsin (eNpHR3.0) in populations of mature and adult-born GCs. Using local circuit mapping in vitro, we will test the hypothesis that adult-born GCs modulate DG output. In vivo, we will test the hypothesis that optical stimulation or inhibition of GCs in the ventral DG preferentially influences anxiety-like behavior, while the dorsal DG impacts spatial learning. Finally, we will dissect the preferential contribution of adult-born GCs to anxiety-like behavior.