Multimodal analysis of primate infragranular pyramidal neurons and their modulation

这个项目的长期目标是确定细胞类型特定表达的后果 离子通道和神经调节剂受体基因对灵长类新皮质功能的影响。人类的大脑是 由数量惊人的细胞类型组成。分子图谱表明，超过75个独特的 神经细胞类型存在于给定的新皮质区域，并且每个区域都有独特的类型。做什么 基因表达的差异会转化为神经元的表型特征吗？解决这个问题是至关重要的 因为一些新出现的证据表明，人类大脑疾病可能有特定细胞类型的病因，其中不同类别的神经元对病理生理学有不同的贡献 这种疾病的危害。 我们打算研究人类和非人灵长类动物中的mrna如何在两个广泛的 新皮质下颗粒下锥体神经元的类别转化为它们独特的生理， 形态和对神经调节的反应。采用最先进的膜片钳技术 通过Patch-Seq技术，我们可以从基因上识别人类和非人类灵长类新皮质中生理学探测到的神经元。我们测试了关于特定离子通道和神经调节剂 受体塑造了这些神经元独特的输入输出特性。我们还利用病毒工具来 前瞻性地标记神经元，特别是第5层(L5)延髓外(ET)投射神经元( 将轴突投射发送到大脑下区域)。有几种类型的L5ET神经元在下丘脑 啮齿类动物的大脑(例如，运动皮质的Betz细胞)。 有三个因素使这项提议与人类健康和疾病特别相关。首先，L5 ET 神经元代表新大脑皮层到许多大脑下结构的唯一直接输出，并且 与多种神经系统疾病有关，包括阿尔茨海默病和肌萎缩侧索硬化症 (ALS)。其次，我们将直接在非人类灵长类动物和人脑切片上工作，而不是 传统的啮齿动物模型。考虑到最近发表的主要研究结果，后一点尤其相关 小鼠和人类锥体神经元生理学的差异。用猴子的组织做实验将会 提供对体内远程轴突投射靶点的直接访问(这对人脑是不可行的 切片)，以及从手术标本中研究人类罕见的大脑区域的能力 (例如，初级运动皮质)。最后，这项建议为最终确定 疾病的细胞类型特异性遗传和药物治疗的发展。

The long-term goal of this project is to determine the consequences of cell-type specific expression of ion channel and neuromodulator receptor genes on primate neocortical function. The human brain is composed of an astonishing number of cell types. Molecular profiling suggests that upwards of ~75 unique neuronal cell types reside in a given neocortical area, and that each area has exclusive types. How do differences in gene expression translate into a neuron’s phenotypic identity? Solving this problem is crucial because several emerging lines of evidence suggest that human brain disorders may have cell type-specific etiologies, wherein different classes of neurons make distinct contributions to the pathophysiology of the disease. We propose to examine in human and nonhuman primates how mRNA expression in two broad categories of neocortical infragranular pyramidal neurons translates into their unique physiology, morphology and response to neuromodulation. Employing a state-of-the-art patch clamping technique, Patch-seq, we can genetically identify physiologically probed neurons from human and non-human primate neocortex. We test hypotheses about how specific ion channels and neuromodulator receptors shape the unique input-output properties of these neurons. We also utilize viral tools to prospectively label neurons, in particular the layer 5 (L5) extratelenephalic (ET)-projecting neurons (which send axonal projections to subcerebral regions). Several types of L5 ET neurons are not found in the rodent brain (e.g., Betz cells of motor cortex). Three factors make this proposal especially relevant for human health and disease. First, L5 ET neurons represent the sole direct output of the neocortex to many subcerebral structures and are implicated in several neurological disorders including Alzheimer’s disease and amyotrophic lateral sclerosis (ALS). Second, we will be directly working in non-human primate and human brain slices rather than the traditional rodent models. The latter point is especially pertinent given recent published findings of major differences in murine and human pyramidal neuron physiology. Experiments with monkey tissue will provide direct access to long-range axonal projection targets in vivo (which isn’t feasible for human brain slices), as well as the ability to study brain areas rarely available in the human from surgical specimens (e.g., primary motor cortex). Finally, this proposal lays the foundational knowledge necessary for eventual development of cell type-specific genetic and pharmacological treatment of disease.