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 奖励联想和动机是引导目标导向行为的关键过程。这些功能 由中脑边缘多巴胺回路调节，包括从腹侧投射的多巴胺神经元 被盖区（VTA）至丘脑核（NAc）。VTA-NAc多巴胺投射广泛地促进了 学习动作和线索结果的关联，并调节目标导向的消失和恢复。 行为。此外，一个新兴的研究机构表明，NAc壳的特定亚区整合了 中脑多巴胺能信号与感觉和边缘系统的输入，以驱动参与维持的行动， 灭绝和恢复寻求奖励的行为。然而，很少有人知道孤立的VTA 向NAc内侧壳的多巴胺输入有助于这些行为。该提案的主要目标是 解剖动机行为中独立的腹侧被盖区投射到NAc内侧壳的神经回路。以限定 一个特定的腹侧被盖区多巴胺投射到NAc内侧壳的作用，我们确定了一个遗传标记，小脑- 4（Cbln 4），其在腹侧被盖区多巴胺神经元的亚群内显示限制性表达。利用病毒- 在Cbln 4-IRES-CRE（Cbln 4 iCre）小鼠中，我发现VTACbln 4神经元投射到NAc， 内侧壳区域而不是外侧壳或核心区域。此外，该电路的体内光学刺激是 在没有主要奖励的情况下，足以促进奖励寻求行为的维持 加固.此外，对这一群体的刺激足以恢复一种熄灭的奖励寻求， 行为反应尽管这些研究信息量很大，但没有研究内源性神经元的作用。 活动或多巴胺信号传导在VTACbln 4-Nac内侧壳电路中的功能， 行为使用具有病毒介导的靶向策略的Cbln 4 iCre小鼠系提出了两个具体目标 解剖VTACbln 4-Nac内侧壳回路。目的1将在解剖学和功能上表征VTACbln 4- Nac内侧壳多巴胺投射的高分辨率定量图像分析和遗传学研究 编码多巴胺传感器与电路特定切片成像相结合。Aim 2使用体内纤维光度法 记录以确定VTACbln 4神经元在获得、消退和线索诱导的刺激期间的神经活动。 恢复食物驱动的操作性反应。此外，这一目标审查的必要性， VTACbln 4-Nac内侧壳回路中的神经活动和多巴胺产生在确定 这些行为使用化学发生抑制和细胞类型特异性CRISPR/SaCas 9介导的基因敲除 接近。这项研究将明确中脑边缘多巴胺回路中的孤立投射如何调节不同的多巴胺受体， 动机行为的各个方面，并深入了解这些回路中的中断如何有助于物质 使用和强迫症。拟议的研究将促进我在体内纤维的培训 测光，离体切片成像，和计算数据分析方法，以及准备我追求一个 作为一名独立研究员。