Dissecting the role of striatal cell types in abnormal repetitive behaviors and treatment response

项目摘要/摘要 尽管不正常的重复行为是突出的、使人残疾的和臭名昭著的-治疗 许多严重的儿童期起病的神经精神障碍的抵抗症状，如强迫症 强迫症(OCD)、抽动症(TS)和自闭症，我们对它们的了解仍然相当有限 它们是如何在大脑中编码的。趋同的临床研究强调了皮质醇的重要性。 纹状体回路在发展异常重复行为中的功能神经成像研究 始终如一地证明1)症状相关的纹状体多动2)通过有效的方法解决 治疗。然而，尚不清楚纹状体的两种主要对立细胞类型--D1型和D2型--是如何带刺的 投射神经元(SPN)在这些异常行为中对纹状体多动起作用，以及活动如何 在这两种细胞类型中受到药物治疗的影响。尽管一个流行的理论认为 内在产生的异常重复运动模式可能是由于过度激活 D1相关的直接通路或D2相关的间接通路激活减少，几乎没有 支持这一观点的直接证据。D_1和D_2-SPN对纹状体的贡献 多动症和这些适应不良的行为，我们使用了一个动物模型系统，显示了这两个 中央纹状体(CS)的多动症与包括强迫梳理和异常的持久性行为 逆转学习(Manning等人，在PREP中)：SAPAP3-KO小鼠。活体显微镜在自由活动中的应用 在动物身上，我们证明了SAPAP3-KO可以增加与梳理相关的纹状体放电频率， 与已发表的作品一致。令人惊讶的是，当我们选择性地检查D1-SPN时，与预期相反 在强迫性美容活动开始时，我们看到与WT相比，活动减少，这表明减少了 D1-SPN对体内皮质输入的反应性。这种活动模式被有效地规范化了 氟西汀治疗。这些数据提示了一种新的模型，在该模型中，D1-SPN的活性降低和过量 D2-SPN的活性促进异常重复行为的启动。在这个项目中，我们将使用状态- 依赖光遗传学、活体显微镜和活体电生理学来直接测试这个模型和 确定有效的氟西汀治疗对纹状体D1、D2和FSI(快脉冲中间神经元)的影响 活动模式。在目标1中，我们将使用in识别异常重复行为期间的D2活动模式 自由活动小鼠的活体显微镜和电生理学。在目标2中，我们将使用活体显微镜来 确定与氟西汀治疗成功相关的D1-和D2-SPN活性模式，并确定 沉默D2-SPN活动是否能概括这种正常化。在目标3中，我们将探索两者之间的关系 FSI活性与氟西汀治疗反应之间的关系。这些研究的最终目标是帮助提炼 以神经刺激为基础的治疗策略，用于使持之以恒和强迫行为失效。

PROJECT SUMMARY/ABSTRACT Despite the fact that abnormal repetitive behaviors are prominent, disabling, and notoriously-treatment resistant symptoms of many severe childhood onset neuropsychiatric disorders such as Obsessive Compulsive Disorder (OCD), Tourette Syndrome (TS), and autism, we still have a quite limited understanding of how they are encoded in the brain. Convergent clinical studies have highlighted the importance of cortico- striatal circuits in the development of abnormal repetitive behaviors, with functional neuroimaging studies consistently demonstrating 1) symptom-associated striatal hyperactivity that is 2) resolved by effective treatment. However, it is unknown how the two major opposing cell-types of the striatum, D1 and D2-spiny projection neurons (SPNs), contribute to striatal hyperactivity during these aberrant behaviors, and how activity in these two cell types is impacted by pharmacologic treatments. Although a prevailing theory suggests that intrinsically-generated abnormal repeated motor patterns might result from either excessive activation of the D1-associated direct pathway or decreased activation of the D2-associated indirect pathway, there is little direct evidence to support this idea. To begin to dissect the contributions of D1 and D2-SPNs to striatal hyperactivity and these maladaptive behaviors, we used an animal model system that displays both hyperactivity in central striatum (CS) and perseverative actions including compulsive grooming and abnormal reversal learning (Manning et al, in prep): SAPAP3-KO mice. Using in vivo microscopy in freely moving animals, we demonstrated that SAPAP3-KOs have increased grooming-associated striatal firing rates, consistent with published work. Surprisingly, when we selectively examined D1-SPNs, contrary to expectations we saw decreased activity compared to WT at initiation of compulsive grooming events, suggesting decreased responsiveness of D1-SPNs to cortical inputs in vivo. This activity pattern was normalized by effective fluoxetine treatment. These data suggest a novel model in which decreased activity in D1-SPNs and excessive activity in D2-SPNs promotes initiation of abnormal repetitive behaviors. In this project we will use state- dependent optogenetics, in vivo microscopy, and in vivo electrophysiology to both directly test this model and determine the impact of effective fluoxetine treatment on striatal D1, D2, and FSI (fast-spiking interneuron) activity patterns. In Aim 1, we will identify D2-activity patterns during abnormal repetitive behaviors using in vivo microscopy and electrophysiology in freely-moving mice. In Aim 2, we will use in vivo microscopy to identify D1- and D2-SPN activity patterns associated with successful fluoxetine treatment, and determine whether silencing D2-SPN activity can recapitulate this normalization. In Aim 3, we will explore the relationship between FSI activity and the fluoxetine treatment response. The ultimate goal of these studies is to help refine neurostimulation-based treatment strategies for disabling perseverative and compulsive behaviors.