Examining Neurocircuit and Behavioral Effects in a Developmental Model for Indirect Pathway Hypofunction

项目摘要 我是一名受过精神病学和神经科学训练的医学博士、内科医生和科学家。我的职业目标是成为一名独立人士 神经科学研究人员，致力于从机制上理解改变的长期贡献 神经发育轨迹到神经精神障碍。我最终希望我的实验室里的发现能 制定新的方法来评估早期生命中的风险因素，并鼓励采取新的治疗和预防方法 神经精神障碍-特别是精神分裂症(SCZ)，一种破坏性的疾病，其发展被认为是 扮演着一个重要但鲜为人知的角色。我设计了一个与我的培训相结合的研究计划 目标和职业发展计划，并将推动我走向科学独立。将鼠标用作我的 模型系统，我打算在这个K08提案中解决的问题集中在纹状体通路的特异性 基底神经节(BG)环路形成过程中的干扰可以塑造发育轨迹并改变其特征 具有持久行为后果的BG电路计算。纹状体中的多巴胺(DA)信号功能障碍 长期以来，前额叶皮质一直与人类的动机和认知缺陷有关。在纹状体， 间接通路神经元中多巴胺D2受体(D2Rs)的表达增加与病因有关 但发育机制仍然有限4-7。小鼠的研究表明，一种非通路特异性 发育中D2R的过度表达导致行为缺陷，与DA信号的改变有关 纹状体和前额叶皮质上的中脑16，17，20，47。同时，出生后早期的化学发生抑制(使用hM4D 间接途径的激活导致皮质纹状体突触的重组，持续至少10天。 提示皮质纹状体连接的发育窗口可能会影响依赖于该回路的行为。在这 在K08提案中，我将带着两个具体的目标来解决这些问题。在目标1中，我将测试以下假设： 在出生后早期发育窗口期抑制纹状体间接通路神经元将导致减少 成年小鼠的动机和认知能力受损。我开发了一种立体定位新生儿适配器， 通过病毒载体改进区域靶向1。初步数据表明，发展对动机行为有影响。在……里面 目标2，我将检验这一假设，即发展操控导致持续的回路水平变化，影响 成人中DA的长期释放，可能是通过改变中脑神经元的活动。我将记录纹状体DA的实时释放 纤维光度法(FP)测定自由活动小鼠的动力学。为了检测活体中脑神经元的活动，我提出了钙离子 在自由行为的动物身上进行成像实验，使用病毒编码的钙指示剂GCaMP6f在中脑神经元中。 我将在纽约州精神病研究所和哥伦比亚大学的导师团队下进行这个项目 克里斯托夫·凯伦东克博士、彼得·巴尔萨姆博士、马克·安索尔日博士、勒内·亨博士、约书亚·伯克博士和乔纳森·贾维奇博士。通过 完成这份职业发展奖提案中列出的培训目标后，我将准备过渡到 在学术医学中心领导研究实验室的科学独立性。

Project Summary I am an MD/PhD physician-scientist trained in psychiatry and neuroscience. My career goal is to become an independent neuroscience investigator devoted to a mechanistic understanding the long-term contributions of altered neurodevelopmental trajectories to neuropsychiatric disorders. I ultimately hope that discoveries made in my lab will generate new ways to assess risk factors during early life, as well as spur novel treatment and preventive approaches to neuropsychiatric disorders—in particular schizophrenia (SCZ), a devastating disorder in which development is thought to play an important but poorly understood role. I have designed a research plan that is integrated with my training objectives and career development plan, and will propel me towards scientific independence. Using the mouse as my model system, the questions I intend to address in this K08 proposal are centered on how striatal pathway-specific perturbations during basal ganglia (BG) circuit formation can shape developmental trajectories and alter the character of BG circuit computations with lasting behavioral consequences. Dysfunctions in dopamine (DA) signaling in the striatum and prefrontal cortex have long been associated with motivational and cognitive deficits in humans. In the striatum, increased expression of dopamine D2 receptors (D2Rs) in indirect pathway neurons have been implicated in the etiology of SCZ, but developmental mechanisms remain limited4-7. Mouse studies have shown that a non-pathway-specific developmental D2R overexpression led to behavioral deficits that were associated with altered DA signaling from the midbrain on striatum and prefrontal cortex16, 17, 20, 47. Meanwhile, early postnatal chemogenetic inhibition (with hM4D activation) of indirect pathway resulted in restructuring of corticostriatal synapses lasting for at least ten days19— suggesting a developmental window for corticostriatal wiring that may shape behaviors dependent on this circuitry. In this K08 proposal, I will address these questions with two Specific Aims. In Aim 1, I will test the hypothesis that transiently inhibiting striatal indirect pathway neurons during an early postnatal developmental window will result in decreased motivation and impaired cognitive performance in adult mice. I have developed a stereotaxic neonatal adaptor that improves regional targeting with viral vectors1. Preliminary data suggest a developmental effect on motivated behavior. In Aim 2, I will test the hypothesis that the developmental manipulation leads to persistent circuit-level changes affecting long-term DA release in adults, possibly by altering midbrain neuronal activity. I will record real-time striatal DA release dynamics in freely behaving mice by fiberphotometry (FP). To examine midbrain neuronal activity in vivo, I propose Ca2+ imaging experiments in freely behaving animals, using a virally-encoded Ca2+ indicator, GCaMP6f, in midbrain neurons. I will conduct this project at the New York State Psychiatric Institute and Columbia University under the mentorship team of Drs. Christoph Kellendonk, Peter Balsam, Mark Ansorge, René Hen, Joshua Berke, and Jonathan Javitch. Through the completion of the training goals delineated in this career development award proposal, I will be prepared to transition into scientific independence leading a research laboratory in an academic medical center.