Behavioral assessment of METH-treated WT and HIV-1 gp120tg mice after seven months of drug abstinence. At 10–11 months, an age- and sex-matched cohort of each group (WT SAL n = 8, WT METH n = 10, HIV-1 gp120tg SAL n = 11, HIV-1 gp120tg METH n = 10) was assessed for behavioral changes. All mice were subjected to all tests. (A) Locomotion tests included measures of ambulation, rearing, center activity and total horizontal activity of the mice. Values are shown for the first 5 min epoch of the testing. For a total of 9 days, shown in consecutive 3-day blocks, animals were assessed in the Barnes maze test: (B) The latencies to enter the escape hole over time (3 day blocks) were determined. (C) The number of errors made over time (3 day blocks) by each animal before finding the correct escape hole (Fig. 1 continued) was determined. (D) Strategies for escaping the maze shown as % of animals per group on the final acquisition trial revealed group differences. Specifically, the use of spatial strategy on the final acquisition trial was greater in HIV-1 gp120tg SAL vs. METH-treated mice. (E, F) The mean percentage of time spent in the target and non-target (‘other’) quadrants was determined in the probe test on day 10. (E): Examining the Target vs. Other difference separately in each group. (F) The differences between average times spent in the target and the other quadrants. All data represented are means ± SEM. Statistical analysis was performed as described in Materials and Methods. * p ≤ 0.05; ANOVAs and post hoc tests (A, B, E, F), Wald-Wolfowitz Test (D). For detailed outcomes of statistical analyses see the Results section. Note that for clarity significant changes between the trial/time blocks in (B) are only reported in the text.