Project Summary We are requesting funds to purchase a Zeiss Axioscan 7 whole slide scanning microscope to enable high-throughput, high resolution automated imaging of standard sized and large format slides in brightfield or multichannel fluorescence modes by NIH supported investigators at UT Southwestern Medical Center in Dallas, TX. For applications where spectral separation of overlapping fluors is essential, the instrument is configured with dedicated single band fluorescence filters to minimize spectral crosstalk between the commonly used Alexa fluors 488, 555, 568/594, and 647. For applications where fluors are sufficiently well separated and speed is most important, we have included multiband filtersets optimized for extremely fast imaging of the Alexa dyes as well as additional fluorophores including DAPI, CFP, YFP, mCherry, DsRed and Cy7, allowing up to 5-channel simultaneous imaging in the same samples. A color camera is included to support acquisition of brightfield/histology images, and the system also accommodates polarized light microscopy for imaging of collagen matrix in tissue sections stained with Picrosirius red. The instrument will be housed in and maintained by the Whole Brain Microscopy Facility (WBMF) and will be available to all investigators on campus. The microscope will complement and expand the capacity of two existing slide scanners within the facility (Zeiss Axioscan.Z1 - 7 years old and Hamamatsu Nanozoomer 2.0-HT - 12 years old) which are heavily used (~45 hours each per week) and lack many features of the newly released (as of April 2021) Axioscan 7. In particular, our existing Nanozoomer was designed for brightfield imaging of histology slides with a very limited fluorescence imaging capability (FITC OR Texas Red single channel imaging). Our existing Zeiss Axioscan.Z1 cannot accommodate imaging of near-infrared fluorophores, 5-channel imaging or polarization microscopy. There are no other slide scanning microscopes with similar capabilities available on the UT Southwestern campus or within a convenient drive for the users described in this application. The WBMF currently supports 164 active users of the slide scanners from 77 individual basic science and clinical labs with a wide variety of project foci. Health related research that will benefit from the requested instrument includes tracking the development of Alzheimer's neuropathology, identification of the neural circuitry for memory generalization and psychosis, characterization of extracellular matrix in the tumor microenvironment and in models of pre-term birth, studies of innate immune response and autoimmune conditions, developing pre-clinical gene therapies for pediatric neurological diseases, and mapping peripheral innervation of the human female reproductive tract.