Deciphering the transcriptomic signatures, physiology, and connectivity of the specialized morphotypes in macaque insular cortex

摘要 从拉蒙·卡哈尔开始，神经科学家们就推测，即使是最复杂的大脑功能也可能- 最终可以在神经元细胞类型及其连接的水平上理解。最近，当我们- 为了了解啮齿动物皮层回路中的细胞类型及其布线原理，我们仍然处于婴儿期， 在细胞类型及其连接的水平上理解灵长类动物皮层的电路组织， 减缓了对初级阶段复杂认知能力的电路水平机制理解的进展， 伙计们例如，人类皮层容纳两种独特的形态类型，von Economo神经元（VEN）和 叉细胞，集中在支持复杂的社会认知能力和自我的皮层区域， 意识很长一段时间以来，VEN和叉细胞被认为是人类和类人猿所独有的， 因此被假设为意识和类似人类的复杂社会行为的神经关联。 尽管它们的重要性，但它们的功能被认为是实验上难以解决的，因为它们具有独特的功能。 对原始人的限制然而，最近的一项研究提供了令人信服的证据，表明这些独特的形态类型 也存在于猕猴的前额叶（AI）中，为人类提供了前所未有的机会。 这些新的神经元在实验室中的功能特性。在这里，通过与中国灵长类动物合作， 利用丰富的猕猴资源和较低的单细胞RNA成本， scRNA-seq测序技术在中国的应用，我们建议借此机会解剖出单核细胞的皮层回路， 关键AI，并在电生理学、形态学、转录组和 连通性。通过利用一套新的成本效益高，高通量的方法，包括大， 规模基于液滴的scRNA-seq，Patch-seq和多细胞补丁记录，我们的目标是识别和表征- 用分子、空间和功能注释确定构成猴AI的所有细胞类型。特别地， 这种对猕猴皮层回路的全面研究将导致详细的功能表征 第一次将VENs和FC结合在一起。重要的是，通过补充两个国家的力量和独特资源， 在美国和中国的合作实验室，我们希望完成这个否则不可行的，昂贵的灵长类动物的重新研究， 在合理的预算和时间范围内进行这种规模的搜索，提供前所未有的知识和重新 该领域的来源，以了解类似人类的社会智能和相关的神经精神的出现 紊乱特别是，鉴定这些新细胞类型的特异性标记基因将促进该领域 开发基因靶向工具，用于研究行为背景下的类人社会认知能力。 有了所有可用的信息和工具，我们对人类智能的理解，以前被认为是前 几乎是棘手的，在很大程度上是投机性的，最终将获得坚实的基础，并准备在2020年起飞。 近期

Abstract Since Ramon y Cajal, neuroscientists have speculated that even the most complex brain functions might even- tually be understood at the level of neuronal cell types and their connections. More recently, while we have be- gun to understand cell types and their wiring principles in cortical circuits of rodents, we are still in infancy in understanding the circuit organization of the primate cortex at the level of cell types and their connections, slowing progress toward a circuit-level mechanistic understanding of complex cognitive capabilities of pri- mates. For instance, the human cortex houses two unique morphotypes, von Economo neurons (VENs) and fork cells, which are concentrated in the cortical regions that support complex social cognitive abilities and self- awareness. For a long time, the VENs and fork cells are believed to be unique to human and great apes, and thus are hypothesized to be the neural correlate of consciousness and human-like complex social behaviors. Despite their importance, their functions are deemed to be experimentally intractable given their exclusive re- striction to hominids. A recent study, however, provides compelling evidence that these unique morphotypes are also present in the anterior insula (AI) of macaque monkeys, providing an unprecedented opportunity for functional characterization of these novel neurons in the laboratory. Here, by partnering with a Chinese primate research laboratory to leverage the abundant macaque resources and lower cost of single-cell RNA- sequencing (scRNA-seq) in China, we propose to take this opportunity to dissect out the cortical circuit of mon- key AI and characterize these novel cell types in terms of electrophysiology, morphology, transcriptome, and connectivity. By taking advantage of a novel set of cost-effective, high-throughput approaches, including large- scale droplet-based scRNA-seq, Patch-seq, and multi-cell patch recordings, we aim to identify and character- ize all the cell types that comprise monkey AI with molecular, spatial and functional annotations. Particularly, this comprehensive interrogation of macaque cortical circuit will lead to a detailed, functional characterization of VENs and FCs for the first time. Importantly, by complementing the strength and unique resources of two collaborating labs in USA and in China, we expect to accomplish this otherwise infeasible, costly primate re- search at this scale within a reasonable budget and time period, providing unprecedented knowledge and re- source for the field to understand the emergence of human-like social intelligence and related neuropsychiatric disorders. Particularly, identifying the specific marker genes for those novel cell types will promote the field to develop genetically targeted tools for studying human-like social cognitive abilities in the context of behaviors. With all information and tools available, our understanding of human intelligence, previously perceived as ex- perimentally intractable and largely speculative, will finally gain solid ground and are ready to take off in the near future.