PROJECT SUMMARY/ABSTRACT Fast microscopy techniques, coupled with recent advances in tissue clearing, are now able to efficiently produce cellular-resolution images of intact brain samples. These technologies have generated three- dimensional (3D) images of entire intact brains from model organisms and large sections of human brain samples, enabling mapping of neuronal circuits from synapse to systems levels. Going forward, it will be essential to share data across laboratories to replicate findings, perform cross-study analyses, and develop robust new analysis tools. The goal of this application is to provide the neuroscience research community with a set of standards for 3D microscopy of intact brains. These standards will facilitate the data comparison and integration necessary for replicating and validating results and for addressing new research questions, amplifying the Brain Research through Advancing Innovative Neurotechnologies (BRAIN) Initiative's investment in technology development. Our approach will be to establish an agile Working Group (WG) of experts and to use a consensus process to establish collaborative standards for brain microscopy. Together, our experienced, multidisciplinary team will establish and disseminate 3D microscopy of intact brain standards through the following specific aims. Specific Aim 1: Establish project operating parameters and assemble a WG of 3D brain microscopy experts. The RTI-UNC team will work with the National Institute of Mental Health (NIMH) project scientist, WG Liaisons, and other stakeholders to assemble a diverse group of scientists who recognize the vision and impact of the project and who have sufficient scientific stature and expertise to represent the community and address the scope. Specific Aim 2: Develop preliminary standards using a consensus process that relies on input from the research community. The WG will develop standards for 3D microscopy of intact brain experiments using a dynamic, collaborative consensus process. The WG will first develop a prototype standard using actual experimental parameters, data, and metadata. The preliminary standards will then be shared with the research community to get feedback and comments that will be considered by the WG as they finalize the set of standards. Specific Aim 3: Raise awareness and promote uptake of 3D brain microscopy standards. The RTI-UNC team will use a multifaceted approach to ensure that the standards are valuable, useful, and widely disseminated. We will develop a browsable, searchable, Web-based resource to host and promote the standards, collaborate with investigators to implement the standards, publish peer-reviewed manuscripts, present at conferences, interact with professional societies to encourage use of the standards, and encourage journals to promote use of the standards in publications.