Changes in exploratory behaviour in the open field after chronic Toxoplasma infection are independent of parasite AaaH2 TH. (A) When compared to controls, both TgWT- and TgAaaH2KO-infected animals showed an increase in the total distance travelled. (B) Infected mice moved at higher speeds than control mice. (C) Relative to controls, a similar lower ability to habituate to the novel environment was observed in infected animals, as shown by the smaller reduction in locomotion over time. (D) Infected animals displayed comparable reduced individual variability in distance covered, relative to controls. (E) An equivalent reduction in the number of movement bouts in both infected groups was observed relative to control animals. (F) All animals executed movement bouts of comparable duration, as no difference was detected between experimental groups. (G) Bout structure was similarly modified in infected mice when compared with controls, with a reduction in the frequency of short bouts and an increase in long bout frequency. (H) Infected mice (irrespective of infective strain) covered higher distances in the border, relative to control mice. (I) Mice in both infected groups moved faster in the center zone than controls. (J) In contrast to control animals, when in the center, infected mice were more frequently engaged in locomotion. (K) Contrary to what was observed in controls, infected animals showed a reduction in the number of non-locomoting periods in the center area. (A–K) Mouse saline group, n = 28; TgWT group, n = 15; TgAaaH2KO group, n = 25. *p < 0.05. The data are presented as the mean ± SEM.