Figure 2.

Shuttle box avoidance test. The avoidance tests were carried out with sound as the CS in the first 3 days. Then light (60 W) was used as the CS for the following 3 days. Finally, the mutant mice were tested for 2 more days with sound as the CS. Eight wild-type mice and five PLC β4-null mice were tested. Data were expressed as means ± SEM and were compared between groups by a non-parametric analysis of variance for unrelated samples (Mann–Whitney U-test).