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Fig. 1. The 30 min training procedure results in a 1-day, but not a 3-day memory. A
cohort of snails (N=24) received operant conditioning training of two
30 min training sessions separated by a 1 h interval (Sessions 1 and 2). In
the first randomly picked group (N=12), we tested for long-term
memory (LTM) 1 day later (Session 3). There was a significant effect between
Sessions 1 and 2 (ANOVA; Fisher's LSD protected t-test,
P<0.01), demonstrating learning (asterisk). As can be seen, LTM
was also demonstrated, i.e. there was no significant difference (NS; Fisher's
LSD protected t-test, P>0.05) between Session 2 and the
1-day memory test Session 3, and the significant difference from Session 1
remained (asterisk). The second group of snails, was tested 3 days later (3
days) and LTM was not demonstrated, i.e. there was a significant difference
(Fisher's LSD protected t-test, P<0.01) between Session 2
and the 3-day memory-test Session 3, but not between this session and Session
1.