Characterization of sexual dimorphism in the brain

项目总结/摘要 深度测序技术彻底改变了我们对大脑中基因表达的理解。特别是单身 许多脑区的细胞RNA测序揭示了转录组学定义的神经元细胞的难以置信的多样性 类型这不仅适用于解剖学定义的大脑区域，如额叶皮层， 神经元群体，例如局限于特定皮质层的那些。这种转录组特异性的多样性 神经元细胞类型是当代神经科学中心目标的重要一步：了解神经元细胞是如何 由特定神经元细胞类型组成的回路调节行为。然而，神经元细胞类型的这种多样性 立即提出了一个问题，即大脑区域（或离散神经元群体）的功能输出是如何 分布在许多转录组学定义的神经元细胞类型，包括该地区。尽管 尽管已经进行了大量的工作来定义这些神经元细胞类型，但它们的功能相关性在大多数情况下仍然不清楚， 如果不是全部的话。我们提出的项目旨在填补这一知识空白，专注于神经元组成的 终纹床核（BNSTpr）的主要成分。我们的基因靶向单核RNA BNSTpr神经元的测序已经鉴定了许多转录组学定义的神经元细胞类型，其中之一被定义为 通过其独特的神经肽速激肽1（Tac 1）的表达。我们开发了交叉遗传策略， 在功能和解剖学上询问表达Tac 1的BNSTpr神经元细胞类型在产生Tac 1的过程中的相关性。 BNSTpr的行为输出。与此同时，我们的遗传策略使我们能够询问 互补Tac 1非表达BNSTpr神经元细胞类型的行为输出的这个区域。在目标1中，我们 使用免疫组织化学方法测定自由活动小鼠中表达Tac 1和不表达BNSTpr神经元细胞类型的活性。 基因编码的钙指示剂。在目标2中，我们将使用交叉光遗传学， 致动器，以确定Tac 1表达和非表达BNSTpr神经元细胞类型的必要性和充分性， 行为在目标3中，我们将Tac 1表达神经元细胞类型的连接性与其功能输出相匹配。 此外，我们将在这些细胞中设计Tacr 1的靶向缺失，Tac 1的同源受体， 投射靶点，并测试在这些投射靶点中通过Tacr 1的Tac 1信号传导是否是行为调节所必需的。 输出.总之，我们的项目将确定一个特定的转录定义的神经元的具体贡献， 细胞类型与行为的关系，与其所在区域的行为输出相反。 健康相关性：BNSTpr是一个整合中心，将感觉输入与运动输出联系起来，用于社会行为， 对情绪和生殖健康至关重要。许多神经精神疾病表现为严重破坏， 社会互动，但这是如何发生的是未知的。我们的工作在分子上指定的神经元细胞类型， 复杂区域具有识别神经回路的潜力，这些神经回路在疾病状态下的中断改变了社会行为。它 因此，可能提示神经精神疾病的潜在靶向治疗或诊断应用。

PROJECT SUMMARY/ABSTRACT Deep sequencing technologies have revolutionized our understanding of gene expression in the brain. In particular, single cell RNA sequencing of many brain regions has revealed an incredible diversity of transcriptomically-defined neuronal cell types. This is true not only for anatomically defined brain regions such as the frontal cortex but also for more discrete neuronal populations such as those confined to a particular cortical layer. This diversity of transcriptomically specified neuronal cell types is a major step forward for a central goal of contemporary neuroscience: understanding how neural circuits composed of specific neuronal cell types regulate behavior. Nevertheless, this diversity in neuronal cell types immediately raises the question as to how the functional output of a brain region (or discrete neuronal population) is parcellated among the many transcriptomically-defined neuronal cell types that comprise that region. Despite the enormous work that has gone into defining these neuronal cell types, their functional relevance remains unclear in most, if not all, instances. Our proposed project seeks to fill this knowledge gap by focusing on the neurons that comprise the principal component of the bed nucleus of the stria terminalis (BNSTpr). Our genetically-targeted single nucleus RNA sequencing of BNSTpr neurons has identified many transcriptomically-defined neuronal cell types, one of which is defined by its unique expression of the neuropeptide tachykinin 1 (Tac1). We have developed intersectional genetic strategies to interrogate functionally and anatomically the relevance of the Tac1-expressing BNSTpr neuronal cell type in generating behavioral output of the BNSTpr. In parallel, our genetic strategies enable us to interrogate the contribution of the complementary Tac1 non-expressing BNSTpr neuronal cell types to behavioral output of this region. In Aim 1, we will determine the activity of Tac1-expressing and non-expressing BNSTpr neuronal cell types in freely moving mice using a genetically encoded calcium indicator in engineered mouse strains. In Aim 2, we will use intersectional optogenetic actuators to determine the necessity and sufficiency of Tac1-expressing and non-expressing BNSTpr neuronal cell types in behavior. In Aim 3, we will match the connectivity of the Tac1-expressing neuronal cell type with functional output of its projection targets; in addition, we will engineer a targeted deletion of Tacr1, the cognate receptor for Tac1, in these projection targets and test whether Tac1 signaling through Tacr1 in these projection targets is essential for behavioral output. Together, our project will determine the specific contribution of a particular transcriptomically-defined neuronal cell type to behavior in contrast to the behavioral output of the region within which it resides. Health relatedness: The BNSTpr is an integrative center linking sensory input to motor output for social behaviors, and it is critical for emotional and reproductive health. Many neuro-psychiatric conditions manifest with severe disruptions to social interactions, but how this occurs is unknown. Our work on a molecularly-specified neuronal cell type within this complex region has the potential to identify neural circuits whose disruption in disease states alters social behaviors. It may therefore suggest potential targeted therapeutic or diagnostic applications for neuro-psychiatric illnesses.