Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2020.10.02.323154v1?rss=1 Authors: Munoz-Castaneda, R., Zingg, B., Matho, K. S., Wang, Q., Chen, X., Foster, N. N., Narasimhan, A., Li, A., Hirokawa, K. E., Huo, B., Banerjee, S., Korobkova, L., Park, C. S., Park, Y.-G., Bienkowski, M. S., Chon, U., Wheeler, D. W., Li, X., Wang, Y., Kelly, K., An, X., Attili, S. M., Bowman, I., Bludova, A., Cetin, A., Ding, L., Drewes, R., D'Orazi, F., Elowsky, C., Fischer, S., Galbavy, W., Gao, L., Gillis, J., Groblewski, P. A., Gou, L., Hahn, J. D., Hatfield, J. T., Hintiryan, H., Huang, J., Kondo, H., Kuang, X., Lesnar, P., Li, X., Li, Y., Lin, M., Liu, L., Lo, D., Mizrachi, J., Mok, S., Nae Abstract: An essential step toward understanding brain function is to establish a cellular-resolution structural framework upon which multi-scale and multi-modal information spanning molecules, cells, circuits and systems can be integrated and interpreted. Here, through a collaborative effort from the Brain Initiative Cell Census Network (BICCN), we derive a comprehensive cell typebased description of one brain structure - the primary motor cortex upper limb area (MOp-ul) of the mouse. Applying state-of-the-art labeling, imaging, computational, and neuroinformatics tools, we delineated the MOp-ul within the Mouse Brain 3D Common Coordinate Framework (CCF). We defined over two dozen MOp-ul projection neuron (PN) types by their anterograde targets; the spatial distribution of their somata defines 11 cortical sublayers, a significant refinement of the classic notion of cortical laminar organization. We further combine multiple complementary tracing methods (classic tract tracing, cell type-based anterograde, retrograde, and transsynaptic viral tracing, high-throughput BARseq, and complete single cell reconstruction) to systematically chart cell type-based MOp input-output streams. As PNs link distant brain regions at synapses as well as host cellular gene expression, our construction of a PN type resolution MOp-ul wiring diagram will facilitate an integrated analysis of motor control circuitry across the molecular, cellular, and systems levels. This work further provides a roadmap towards a cellular resolution description of mammalian brain architecture. Copy rights belong to original authors. Visit the link for more info