The Models Evaluation and Maintenance Core responds to the needs of the individual research sections by preparing specific animal models that are evaluated and maintained to meet prestated criteria. Such models are initiated by the program investigators based upon existing literature, scientific communication, or ideas originating internally. Once a decision is made to test a new model, this Core become involved. This includes helping to pick and evaluate dosing regimens and verifying that the chosen dosing regimen perturbs the nervous system in a characteristic, desired fashion. When a reproducible dosing model is established, this Core then provides treated animals to be used in both individual and collaborative research studies sponsored by the Program. The activities of this Core result in uniform, well-monitored animal models for program investigators. It also ensures that an animal model used by more than one research section remains consistent between the research sections, permitting better comparisons of data. The core also facilitates continuity of the Program by providing accurate record-keeping so that information can be retrieved at any time. A secondary goal of this core is to assist in utilizing available analytical methods for verification and quantification of toxicant treatment. This may include procedures necessary to characterize molecules necessary for studies done by individual research projects or procedures required for models used by many sections. Not only does the Models Evaluation and Maintenance Core provide an efficient way to manage these needs but, by acting a central resource, it also facilitates communication among the investigators.