The overall aim of the proposal is to equip animal facilities in a manner consistent with current NIH and AAALAC standards by providing primate and ventilated mouse caging for a 57,600 gross square foot animal facility due to open in September 2005 as part of a new $160 million neuroscience complex. The following specific aims are documented in this proposal. 1. Purchase of ventilated rack systems for housing genetically engineered mice to accommodate an increased census. 2. Purchase of stainless steel caging for nonhuman primates to accommodate an increased census and paired housing. The specific improvements are directly related to the long term goal of MIT's Animal Resource Program, which is to provide the best possible environment for scientific inquiry supported by NIH and other sources, concurrently maintain AAALAC accreditation, and ensure the highest standards of humane care and use of laboratory animals.