Figure 4

Normal memory ability of CS-KO mice in the other memory-related tests (fear learning, depression learning, and motor learning). In the fear conditioning test (A), the freezing response with tone-shock conditioning was normal in CS-KO mice (left). Freezing during contextual testing was not significantly different between genotypes (center). In cued testing, CS-KO mice showed essentially normal freezing responses (right). During the time indicated by horizontal bold lines, tone stimuli were given. Arrows indicate the time points of foot shock stimuli. In the passive avoidance test (B), CS-KO mice showed normal latency to enter the dark side of the passive avoidance chamber, compared with WT mice in training (B left). Seven days after training, the latency to enter the dark side significantly increased compared with the training trial in both genotypes (B right). We detected a small, but not significant decrease in CS-KO mice in day 7. In the Porsolt forced swimming test (C), CS-KO mice displayed a normal immobility during the whole 10-min forced swimming session (C left). On the next day, during the whole 10-min session, immobility characteristics seemed to be the same in the two genotypes (C right). (*) CS-KO mice displayed decreased immobility compared with WT mice only in the first 1 min block (P = 0.0037). Rotarod performance of CS-KO mice (D) was normal compared with WT mice during the trials. Data are expressed as mean ± S.E.M.