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SUMMARY Single cell genomics has revolutionized our understanding of neuronal cell types. However, scalable technologies for probing single-cell connectivity are lacking, and we are just beginning to understand how molecularly defined cell types are organized into functional circuits. Here, we describe a protocol to generate high-complexity barcoded rabies virus (RV) for scalable circuit mapping from tens of thousands of individual starter cells in parallel. In addition, we introduce a strategy for targeting RV-encoded barcode transcripts to the nucleus so that they can be read out using single-nucleus RNA sequencing (snRNA-seq). We apply this tool in organotypic slice cultures of the developing human cerebral cortex, which reveals the emergence of cell type– specific circuit motifs in midgestation. By leveraging the power and throughput of single cell genomics for mapping synaptic connectivity, we chart a path forward for scalable circuit mapping of molecularly-defined cell types in healthy and disease states. 

Abstract The nucleus is a complex many-body system with some remarkable emergent collective properties of multiple nucleons acting together. Bohr and Mottelson [1] provided a description of collective motion in nuclei based on geometrical shapes with superimposed oscillations around those shapes. Later, Lie algebras and symmetries were used to describe nuclear dynamics [2], followed by advances in the shell model approach [3] with new effective nucleon-nucleon two- and three-body interactions, and more recently with Hartree-Fock-Bogoliubov approximations within the extended generator coordinate method [4]. Yet, the underlying science question has remained the same. In nuclei, where there is explicit deformation in the ground state, “are the low-lying 0⁺states collective vibrations built on the ground state or are they minima of a coexisting shape?” Ref. [4] has shown that for a significant percentage ofK= 0⁺excitations built on the deformed ground state (g.s.) should, in fact, be a collective vibration. The question has remained open due to sufficiently convincing experimental data with lifetimes, transfer reaction cross sections, andE0 transitions [5]. This paper summarizes the experimental situation regarding the lifetimes of 0⁺states. 

The museum field has begun exploring the effects of facilitation on visitors’ learning, focusing on facilitation by museum staff inside museum buildings. However, some museum professionals contend that museums have a responsibility to serve their communities in the spaces where community members spend time, rather than expecting the public to come to them. Less is known about the effects of facilitation on visitors in urban outdoor spaces where interactions with facilitators are unexpected. The present study contributes to this line of literature by describing a quasi-experimental study that assessed the effects of exhibition facilitation led by community stewards using a trauma-informed approach in an outdoor, freely accessible civic plaza. Video observation and visitor interview data were collected. The present study found that facilitation increased visitors’ exhibit usage, overall satisfaction, and some but not all assessed areas of affective and metacognitive learning. The study highlights the value of research conducted in partnership and the power of content-humanizing facilitation.