Figure 5. (A, B) Spatial memory performance and (C) swim speed in a radial arm water maze and (B’, C’’) simple linear regressions for circulating and central steroid hormones among young adult and middle-aged HIV-1 Tat-transgenic male mice [Tat(+)] or their non-Tat-expressing age-matched counterparts [Tat(−)]. (A) Proportion of mice that exhibited improvement from day one performance (latency to escape). (B) Total frequency of errors. (C) Swim speed (cm/s). Simple linear regressions between (B’) circulating estradiol and frequency of errors, (C’) circulating corticosterone and swim speed, and (C’’) progesterone and swim speed. *main effect for Tat(+) mice to differ from Tat(−) mice. ^interaction effect wherein indicated group differs from young adult Tat(−) controls. ||indicates middle-aged differs from young-adult groups. ‡indicated middle-aged Tat(+) groups differs from middle-aged Tat(−) and young adult Tat(+) mice. Regression lines (solid) are depicted with 95% confidence intervals (dotted), (repeated measure ANOVA, p < 0.05).