This NCRR shared instrumentation grant application requests funds for an optical imaging system. This system is designed to directly visualize neural activity in relation to different stimulus conditions. Signals are imaged from the cortical surface of awake or lightly anesthetized animals. The method relies on the discrimination of changes in intrinsic signals which correlate with levels of neural activity. The intrinsic signals that are imaged have been proposed to arise, in part, from local changes in the ratio of oxy- to deoxyhemoglobin that are known to accompany changes in neural activity. This powerful method has been used successfully to determine not only how maps of different stimulus properties are arranged relative to one another, but also how maps develop or change over time under different manipulation conditions. This method is also compatible with a variety of other tools such as standard single unit recording and many anatomic techniques. In this proposal, a group of six investigators will share the optical imaging system. All of these investigators work well together and have funded projects that will greatly benefit from the new technology provided by optical imaging. Seven projects are described of which six are proposed as part of funded projects or are appropriate to one or more aims of this funded research. The other project represents an example of new directions that will enhance the research of several investigators and provide new opportunities for collaboration with the group. The equipment will be housed in the Department of Psychology within research space contiguous to animal quarters. Mechanisms are in place to provide administrative support to monitor and manage the day-to-day and long-term user of the optical imaging system, as well as to support others at Vanderbilt or nearby institutions interested in using this system for their research. The optical imaging initiative will provide an ideal interface between wet-lab and clinical neuroscience and the new fMRI initiatives at Vanderbilt. In summary, this shared system would greatly enhance on-going research and provide opportunities for exciting new directions for the Vanderbilt Neuroscience community.