This application is to replace and expand a central rodent EEG monitoring facility at the University of Virginia. This facility has had a central role n epilepsy and seizure research for over 20 years and has supported the efforts of a number of neuroscience investigators during that time. Many students and post-doctoral fellows have learned the technique as part of their training. Epilepsy and status epilepticus continue to be a major public health problem in the United States, and progress will be made through the use animal models that provide data that are clinically relevant. The growth of rodent models of epilepsy characterized by spontaneous seizures have provided a number of important insights into the pathophysiology of different types of epilepsy, but documenting and quantifying these spontaneous and unpredictable events limits the application of these models. The development and implementation of these new rodent models has been facilitated by the simultaneous development of long term EEG- video monitoring. This technology was first developed for the clinic, but it has been modified for use in the laboratory. The principal investigator for this application was one of the first to develop and use prolonged EEG recordings in multiple rats simultaneously, and he has worked over the years to improve the ease of use and to broaden the applicability of the technology. The application is submitted now because there is a critical need to replace the system. The current system has hardware that is now over 8 years old, and it is no longer supported by the manufacturer. Computer components are failing and key replacement parts are no longer available. The system could cease to function at any time and thereby place a number of NIH funded projects in jeopardy. The presence and availability of the monitoring system has encouraged new investigators to develop projects that use EEG monitoring and has been used by established investigators to establish new lines of research. The unit has become an essential facility at the University for in vivo rodent neuroscience research, and it must be maintained.