The numbers of trials were determined depending on the results
in 1.. Because we found that the 10 trials of CS2–UCS
were suitable instead of the 30 trials of CS2–UCS see the
results for the details., we conditioned Lymnaea by the 30
CS1–CS2 trials and the 10 CS2–UCS trials. The immediate
conditioning tests were performed in the same way as
in 1.. For the controls, partial conditioning groups, CS1–
CS2. and CS2–UCS., and a naive group were employed.
The number of Lymnaea employed was 16 each. The data
were expressed as means"S.E. and evaluated for statisti-
cal significance p-0.05. with one-factor ANOVA and
post-hoc test Fisher’s PLSD. or t-test.