Figure 8. (A) Elevated zero maze performance of H₃R^−/− and wild-type mice.

(A) For the experiments examining the times spent in open areas, *P<0.05; n=10–12 mice per genotype. (B) Barnes maze performance of H₃R^−/− and wild-type mice. On days 1–4, mice were trained to locate a hidden escape tunnel, and on day 5, two probe trials were used with the tunnel placed under different holes. On days 6–9, mice were trained to locate a visible escape tunnel. H₃R^−/− mice moved less than the wild-type mice moved to locate the hidden platform location (P<0.05). There was no group difference in the number of errors, perseverance, or in the distribution of search strategies used to locate the hidden escape tunnel (n=11–12 mice per genotype). (C) Acoustic startle response of H₃R^−/− and wild-type mice. The mice were tested using acoustic stimuli between 80 and 120 dB for 30 ms, and the startle amplitude was recorded. H₃R^−/− mice showed significantly higher startle amplitudes than wild-type mice (overall ANOVA, P<0.05). *P<0.05, lowest intensity significantly different from baseline; n=11–13 mice per genotype.