The Animal Care and Use Committee of both the Seton Hall University and University of Virginia approved this study. Adult male HIV-1Tg rats and F344 background control rats (n = 12 per group) were purchased from Harlan Inc. (Indianapolis, IN). All rats were double housed in standard plastic cages and maintained in a temperature-controlled environment with a 12 h light/dark cycle and fed a standard rat diet and water ad libitum. The animals were monitored daily, and their cage bedding was changed twice a week. All animals were participants in a previously reported behavioral study [31]. All experimental procedures were conducted during the light cycle in accordance with the Animal Care and Use Committees of both participating institutions.