Optogenetic dissection of dentate gyrus circuitry underlying anxiety

描述（由申请人提供）：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的神经回路，最终将此见解用于转化研究。 为了实现这一目标，我提出了一个项目，通过检查齿状回（DG）回路如何有助于焦虑样行为，为我提供了重要的培训。具体来说，我将研究是否发育起源或区域位置的DG颗粒细胞（GC）决定了他们的情绪行为的贡献。 为了测试这个，我将使用 光遗传学技术来控制成熟和成年出生的颗粒细胞在背侧的活动 或腹侧DG，以确定它们对焦虑样行为的相对贡献。我的主要专长是小鼠行为，分子生物学和小鼠遗传学。 我的职业发展计划将在此基础上进行扩展，为我提供膜片钳电生理学、体内电生理学和行为过程中的体内光遗传神经调节方面的基本培训。 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，而且对我成功领导全面的独立研究事业至关重要。此外，由于我以前的重点是基础研究，我建议扩大我在转化神经科学方面的培训，这样我就可以应用我的研究与临床医生成功合作。研究项目 确定焦虑和抑郁的电路机制对于治疗精神疾病至关重要。 在这个建议中，我将研究齿状回（DG）如何有助于焦虑样行为。 虽然经典研究其作用， 空间学习，有一个重要的支持DG在情绪行为中的作用，但 其机制尚不清楚。 一个潜在的机制来自观察情绪状态可以影响新的颗粒细胞（GC）的生产从位于成人DG的干细胞。此外，最近的研究表明，海马体是功能分离的沿着其背腹轴，影响焦虑样行为通过其腹极。这表明GC代表了一个功能异质的神经元库，由其发育起源局部决定，并由其位置沿着背腹侧轴的海马区域。为了测试这些可能性，我们选择性地表达了蓝光激活的阳离子通道通道视紫红质-2（ChR 2）和黄光激活的氯离子泵盐视紫红质（eNpHR3.0）在成熟和成人出生的GC群体。使用本地电路映射在体外，我们将测试的假设，成人出生的GC调制DG输出。在体内，我们将测试的假设，光学刺激或抑制GC在腹侧DG优先影响焦虑样行为，而背侧DG影响空间学习。最后，我们将剖析成人出生的GC的偏好性贡献焦虑样行为。 公共卫生相关性：这是第一个研究调节齿状回局部回路如何有助于焦虑样行为的建议。 确定焦虑和抑郁的基础电路将为开发新的疗法和治疗方法提供新的途径，这将有利于治疗情绪障碍。

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. PUBLIC HEALTH RELEVANCE: This proposal is the first to examine how modulating local circuits in the dentate gyrus can contribute to anxiety-like behavior. Identifying the circuits tht underlie anxiety and depression will provide new avenues for developing novel therapies and treatments that would be beneficial for the treatment of mood disorders.