This laboratory core will provide a central facility for the surgical preparation and injury of all rats subjected to fluid percussion injury in this program project. As a function of this core, all injuries will be produced in a standardized manner so that results from the different projects will be entirely comparable. The core will also provide behavioral testing, ranging from assessments of transient behavioral suppression to long-term behavioral deficits in motor and cognitive function, to standardize all behavioral analyses considered in those projects with behavioral endpoints. Lastly, the core facility will provide a range of histopathological services. These will include the random histopathological analyses of injured rat brains to assure the consistency of the chosen injury level. Also more detailed histopathological studies will be performed on animals used in the studies proposed by Drs. Phillips and Bullock. The brains of these animals will be prepared either for routine light microscopic analysis or immunocytochemical analyses conducted at the light and electron microscopic level. Lastly, select human samples derived from the clinical studies of Drs. Bullock and Muizelaar will also be processed for light and electron microscopy. This facility will maximize the use of personnel, space and equipment in order to achieve the overall goals of the program project grant.