人类神经类器官代表了研究神经功能的有前景的模型；然而，体外生长的类器官缺乏某些被认为对成熟至关重要的微环境和感觉输入。将患者来源的神经类器官移植到动物宿主中有助于克服其中一些限制，并为神经类器官成熟和电路整合提供了一种方法。在这里，我们描述了一种将人类干细胞衍生的皮质类器官（hCO）移植到新生大鼠体感皮层的方法。人类诱导多能干细胞分化为 hCO 需要 30-60 天，每只动物的移植过程本身需要约 0.5-1 小时。新生儿宿主的使用为电​​路整合提供了一个适合发育的阶段，并允许在活体动物宿主的皮层内生成和实验操作人类神经组织单元。移植后，动物可以维持数百天，并且可以使用脑磁共振成像监测移植的 hCO 生长。我们描述了通过监测基因编码的钙反应和细胞外活动来评估体内人类神经回路功能。为了证明人类神经元-宿主功能整合，我们还描述了一种通过使用光遗传学行为训练范例来参与宿主神经回路和调节动物行为的程序。然后，移植的人类神经元可以进行跨模式的离体表征，包括树突形态重建、单核转录组学、光遗传学操作和电生理学。这种方法可能能够从患者来源的细胞中发现细胞表型，并揭示有助于人类大脑从以前无法进入的发育阶段进化的机制。© 2024。Springer Nature Limited。

Human neural organoids represent promising models for studying neural function; however, organoids grown in vitro lack certain microenvironments and sensory inputs that are thought to be essential for maturation. The transplantation of patient-derived neural organoids into animal hosts helps overcome some of these limitations and offers an approach for neural organoid maturation and circuit integration. Here, we describe a method for transplanting human stem cell-derived cortical organoids (hCOs) into the somatosensory cortex of newborn rats. The differentiation of human induced pluripotent stem cells into hCOs occurs over 30-60 days, and the transplantation procedure itself requires ~0.5-1 hours per animal. The use of neonatal hosts provides a developmentally appropriate stage for circuit integration and allows the generation and experimental manipulation of a unit of human neural tissue within the cortex of a living animal host. After transplantation, animals can be maintained for hundreds of days, and transplanted hCO growth can be monitored by using brain magnetic resonance imaging. We describe the assessment of human neural circuit function in vivo by monitoring genetically encoded calcium responses and extracellular activity. To demonstrate human neuron-host functional integration, we also describe a procedure for engaging host neural circuits and for modulating animal behavior by using an optogenetic behavioral training paradigm. The transplanted human neurons can then undergo ex vivo characterization across modalities including dendritic morphology reconstruction, single-nucleus transcriptomics, optogenetic manipulation and electrophysiology. This approach may enable the discovery of cellular phenotypes from patient-derived cells and uncover mechanisms that contribute to human brain evolution from previously inaccessible developmental stages.© 2024. Springer Nature Limited.