Figure 5

Behavioral impairments in DTg mice. (A – C) Morris water maze test. Acquisition rates in the hidden platform task did not significantly differ between DTg mice and WT mice (A, N = 23 for WT, N = 24 for DTg), but DTg mice spent significantly less time in the target quadrant during the probe test than did WT mice (B). Dashed line indicates chance level. No difference was observed between genotypes in the visible platform task (C). (D, E) DTg mice treated with Dox (DTg Dox) were not impaired in the hidden platform task (D) or probe test (E, N = 24/genotype). (F – H) Fear-conditioning and footshock sensitivity test. (F, G) Each column represents mean percent time freezing during the last 2-min recording period for conditioning, 5-min recording for contextual test, and the last 3-min recording period for cued test. DTg mice showed normal contextual and cued fear memory at 1 d and 2 d after conditioning, respectively (F). In contrast, DTg mice exhibited significantly reduced remote contextual fear memory at 30 d after conditioning (G), whereas they showed normal remote cued fear memory (G) and footshock sensitivity (H, N = 12 for each genotype). (I – K) DTg mice treated with Dox were not impaired in recent (I) or remote (J) fear memory, or footshock sensitivity (K, N = 12 for each genotype). *P < 0.05, **P < 0.01, unpaired t test. Results are provided as mean ± SEM. Flinch, animal flinched; Vocal, animal vocalized; S jump, small jump; B jump, big jump.