Twenty-four, male Tg mice (3–5 months old) expressing the HIV-1 tat (Tat+) or lacking the tat transgene (Tat−) were used for this study. Tg mice were generated and housed in an environmentally controlled vivarium (12 h light/dark cycle; lights off at 6 pm) at Virginia Commonwealth University. Food and water were provided ad libitum. Expression of Tat was targeted preferentially to the nervous system in Tg mice via a GFAP-driven, reverse tetracycline transactivator (rtTA or tetracycline-on promoter) that was activated with doxycycline (DOX)-containing mouse chow as previously described (Bruce-Keller et al., 2008 (link); Hauser et al., 2009 (link)). Tat− mice expressing the rtTA promoter served as controls. DOX-containing chow (6 g/kg; Harlan Laboratories, Madison, WI) was freely available to both Tat+   and Tat− mice for 8 weeks. All procedures were approved by the Virginia Commonwealth University Institutional Animal Care and Use Committee and conformed to the Guide for Care and Use of Laboratory Animals (National Research Council, Washington DC).