Abstract
Avoidance, discrimination (right-left) and discriminated avoidance performances of 15 inbred strains of mice were measured on 50 learning trials in each of two daily sessions with a specially designed automated Y-type maze apparatus. Each trial consisted of light and buzzer for five seconds as conditioned stimuli and electric shock for five seconds as an unconditioned stimulus. Intertrial intervals were 30 seconds. The subjects were ten animals of 60-75 days of age for each sex. Highly significant differences among the strains for all the learning performances and negative correlations between the avoidance and discrimination performances of the strains were observed. This suggests that different strains should be chosen for avoidance and for discrimination, when used in behavioral experiments. Among the strains RF/Ms, SWM/Ms and SWR/Ms were superior in avoidance, while C3H/HeMs, DBA/2 and DBAf/Lw were superior in discrimination. C3H/HeMs and C57BL/6HeMs had relatively high abilities for both learning tasks. D103/Ms had the lowest learning ability in avoidance, while SWM/Ms and SWR/Ms had the lowest in discrimination.
