PROJECT SUMMARY: HISTOLOGY SERVICE MODULE The Vanderbilt Vision Research Center (VVRC) includes faculty investigators with a strong interest in discerning structure-function relationships in the visual pathways. These include inferences based on whole tissue analysis, single cell labeling, and localization of molecular components of biochemical cascades in involved in intra- and extracellular signaling. Such inferences require access to expert histological processing and labeling. The purpose of the VVRC Histology Module is to provide a comprehensive service for all tissue preparation, sectioning and staining/labeling for investigator laboratories needing supplemental provision in these areas not covered by staff members supported by their individual grants. In the current funding period the histology service trained 15 staff members and 10 students/fellows and contributed material for 17 investigators, 10 of whom authored 41 publications using the service. Availability of this module during the current period saved VVRC investigators $262,184 in histology services. A survey of researcher plans indicates that the use of this service will increase, with moderate to extensive use by 21 of 36 VVRC investigators. The histology module, housed in the research space of the Department of Ophthalmology & Visual Sciences/Vanderbilt Eye Institute, is directed by VVRC Director and P30 Primary Investigator David Calkins, PhD. Using this space and personnel supported in part by this Core mechanism, the VVRC Histology Module will: (1) assist or supervise preparation of visual system tissues suitable for sectioning; provide a broad range of (2) tissue embedding capabilities and (3) sectioning of visual system structures; (4) support a diverse array of histological and immuno-labeling stains; (5) provide access to automated conventional microscopy and image processing software; and (6) train members of the vision research community on basic histological techniques. These services and resources will enhance the scope of experimentation NEI-funded VVRC investigators conduct, expand the training of students and fellows involved in vision science, and promote collaboration by providing histological support to those who otherwise would not have such capabilities, including early-career vision scientists and clinician-scientists competing for extramural funding for their laboratories.