Figure 4

Dietary soy phytoestrogen's influence on a 4-arm (working and reference memory) task (baited/unbaited) in the radial arm maze. Long-Evans rats (males and females) received a life-long exposure to a high-phytoestrogen containing diet (Phyto-600, from conception to adulthood). In adulthood, one-half of the total number of male or female (random cycling) rats were either: 1) kept on the original high phytoestrogen diet (Phyto-600) or 2) changed to a phytoestrogen-free (Phyto-free) diet. Number of correct arm choices, made in the first four arm entries (Mean ± SEM; average of 3 trials). A correct choice was defined as an entry into a baited arm not yet visited in the trial. a. Phytoestrogen-600 females made significantly more correct choices than Phytoestrogen-free females a' and Phytoestrogen-600 males a" (p < 0.05) on trials 1–12. b. Phytoestrogen-600 females made significantly more correct choices than Phytoestrogen-600 males b' (p < 0.05) on trials 10–12. c. Phytoestrogen-free males made significantly more correct choices than Phytoestrogen-free females c' (p < 0.05) on trials 7–9. d. Phytoestrogen-free males made significantly more correct choices than Phytoestrogen-600 males d' (p < 0.05) on trials 10–12. e. Phytoestrogen-free males made significantly more correct choices than Phytoestrogen-600 males e" and Phytoestrogen-free females e' (p < 0.05) on trials 13–15.