This Funding Opportunity Announcement (FOA) supports Comprehensive Centers to develop and test technologies that can be scaled to brain-wide atlases of mouse circuit connectivity. Centers will establish data collection, analysis, and dissemination pipelines to demonstrate the feasibility of mapping cell-to-cell connectivity with a minimum resolution of synaptic connections. They will demonstrate the significance of the approach within the context of a chosen CNS sub-volume, by testing specific hypotheses relating circuit structure to function. They will also incorporate toolsets and infrastructure for integrating separately collected data from smaller volumes, as well as from other data collection modalities, and for enabling the neuroscience community to interact with and mine the data for new research questions. Centers will be integrated into the BRAIN CONNECTS Network, consisting of projects from this FOA and its companion announcements, as a coordinated effort aimed at developing wiring diagrams that can span entire brains across multiple scales.