Elucidating the role of the VTA-NAc medial shell projection in motivation, extinction, and reinstatement

阐明 VTA-NAc 内侧壳投射在动机、消退和恢复中的作用

• 批准号: 10574485
• 负责人: Jordan Elum
• 金额: $ 4.23万
• 依托单位: UNIVERSITY OF WASHINGTON
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-02-10 至 2024-02-09
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10574485
• 关键词: Acute; Anatomy; Appetitive Behavior; Attenuated; Behavior; Behavioral; Brain; CRISPR/Cas technology; Clustered Regularly Interspaced Short Palindromic Repeats; Computer Analysis; Coupled; Cues; Custom; Data; Data Analyses; Desire for food; Disease; Dopamine; Extinction; Fiber; Food; Genetic; Genetic Markers; Goals; Image; Image Analysis; Internal Ribosome Entry Site; Lateral; Learning; Light; Maintenance; Maps; Medial; Mediating; Methods; Midbrain structure; Motivation; Mus; Neurons; Nucleus Accumbens; Obsessive-Compulsive Disorder; Opsin; Optics; Outcome; Pattern; Photometry; Population; Preparation; Process; Production; Psychological reinforcement; Regulation; Research; Research Personnel; Resolution; Rewards; Role; Sensory; Signal Transduction; Slice; Substance abuse problem; Synapses; Synaptophysin; System; Testing; Training; Tyrosine 3-Monooxygenase; Ventral Tegmental Area; Viral; Work; analysis pipeline; behavioral response; career; cell type; density; designer receptors exclusively activated by designer drugs; dopamine system; dopaminergic neuron; genetic approach; in vivo; insight; knockout gene; mesolimbic system; motivated behavior; nervous system disorder; neural; neural circuit; neuropsychiatric disorder; novel; optogenetics; quantitative imaging; response; sensor; substance use; substance use treatment; therapeutic development; therapeutic target

PROJECT SUMMARY Reward association and motivation are key processes guiding goal-directed behaviors. These functions are modulated by mesolimbic dopamine circuitry, which encompasses dopamine neurons projecting from the ventral tegmental area (VTA) to the nucleus accumbens (NAc). VTA-NAc dopamine projections broadly facilitate the learning of action- and cue-outcome associations and regulate the extinction and reinstatement of goal-directed behaviors. Further, an emerging body of research suggests that specific subregions of the NAc shell integrate midbrain dopaminergic signals with sensory and limbic inputs to drive actions involved in the maintenance, extinction, and reinstatement of reward-seeking behaviors. However, little is known about how isolated VTA dopamine inputs to the NAc medial shell contribute to these behaviors. The primary goal of this proposal is to dissect the neural circuitry of isolated VTA projections to the NAc medial shell in motivated behavior. To define the role of a specific VTA dopamine projection to the NAc medial shell, we identified a genetic marker, cerebellin- 4 (Cbln4), that displays restricted expression within a subpopulation of VTA dopamine neurons. Using viral- mediated circuit mapping in Cbln4-IRES-CRE (Cbln4iCre) mice, I found that VTACbln4 neurons project to the NAc medial shell region but not lateral shell or core regions. Additionally, in vivo optical stimulation of this circuit is sufficient to facilitate the maintenance of reward-seeking behaviors in the absence of primary reward reinforcement. Further, stimulation of this population is sufficient to reinstate an extinguished reward-seeking behavioral response. Although highly informative, these studies did not examine the role of endogenous neural activity or dopamine signaling in the VTACbln4-Nac medial shell circuit for its functions in modulating motivated behavior. Two specific aims are proposed using the Cbln4iCre mouse line with viral-mediated targeting strategies to dissect the VTACbln4-Nac medial shell circuit. Aim 1 will anatomically and functionally characterize the VTACbln4- Nac medial shell dopamine projection using high resolution quantitative image analysis and a genetically encoded dopamine sensor coupled with circuit-specific slice imaging. Aim 2 uses in vivo fiber photometry recording to determine the neural activity of VTACbln4 neurons during the acquisition, extinction, and cue-induced reinstatement of food-motivated operant responding. Further, this aim examines the necessity of endogenous neural activity and dopamine production in the VTACbln4-Nac medial shell circuit in determining the expression of these behaviors using chemogenetic inhibition and cell-type specific CRISPR/SaCas9-mediated gene knockout approaches. This study will define how isolated projections within mesolimbic dopamine circuitry regulate distinct aspects of motivated behavior and provide insight into how disruptions in these circuits contribute to substance use and obsessive-compulsive disorders. The proposed studies will facilitate my training in in vivo fiber photometry, ex vivo slice imaging, and computational data analysis methods, as well as prepare me to pursue a career as an independent researcher.

项目摘要 奖励关联和动机是指导目标指导行为的关键过程。这些功能是 通过中侧多巴胺电路调节，该电路包括腹侧突出的多巴胺神经元 伏隔核（NAC）的对盖区域（VTA）。 VTA-NAC多巴胺预测广泛促进 学习行动和提示结果协会，并规范目标定向的灭绝和恢复原状 行为。此外，新兴的研究表明，NAC壳的特定子区域集成 中脑多巴胺能信号具有感官和边缘输入，以驱动涉及维护的动作， 灭绝和恢复寻求奖励行为。但是，关于如何孤立的VTA知之甚少 NAC内侧壳的多巴胺输入有助于这些行为。该提议的主要目标是 在动机行为中，将孤立的VTA投影的神经回路向NAC内侧壳进行了解剖。定义 特异性VTA多巴胺投影对NAC内侧壳的作用，我们确定了遗传标记，小脑 - 4（CBLN4），在VTA多巴胺神经元的亚群中显示受限制的表达。使用病毒 CBLN4-IRES-CRE（CBLN4ICRE）小鼠中介导的电路映射，我发现VTACBLN4神经元向NAC进行了项目。 内侧外壳区域，但不是横向外壳或核心区域。另外，该电路的体内光学刺激为 足以在没有主要奖励的情况下促进维持寻求奖励行为 加强。此外，对该人群的刺激足以恢复灭绝的寻求奖励 行为反应。尽管有很高的信息，但这些研究没有检查内源性神经的作用 VTACBLN4-NAC内侧壳电路中的活动或多巴胺信号传导，以调节动机 行为。使用具有病毒介导的靶向策略的CBLN4ICRE小鼠系提出了两个具体目标 剖析VTACBLN4-NAC内侧壳电路。 AIM 1将在解剖和功能上表征VTACBLN4-- 使用高分辨率定量图像分析和遗传学上的NAC内侧壳多巴胺投影 编码的多巴胺传感器以及电路特异性切片成像。 AIM 2在体内纤维光度法中使用 记录以确定在获取，灭绝和提示诱导期间VTACBLN4神经元的神经活动 恢复食物动机的作战者的响应。此外，此目的检查了内源性的必要性 VTACBLN4-NAC内侧壳电路中的神经活动和多巴胺产生在确定表达 这些行为使用化学发生抑制和细胞型特异性CRISPR/SACAS9介导的基因敲除 方法。这项研究将定义中甲贝胺多巴胺电路中的孤立投影如何调节不同 动机行为的各个方面，并洞悉这些电路中的破坏如何有助于实质 使用和强迫症。拟议的研究将促进我在体内纤维中的培训 光度法，离体切片成像和计算数据分析方法，并为我做好准备 作为独立研究人员的职业。