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. 2003 Jan;10(1):44–54. doi: 10.1101/lm.48703

Figure 4.

Figure 4

Associative learning in a regenerated nervous system demonstrated by a different testing procedure. The operant conditioning procedure of two 30-min. training sessions for 2.5 d followed by a savings-test session 1 wk later was imposed on two cohorts of snails; a sham-operated cohort (A) and a functionally regenerated group (B). A third cohort of functionally regenerated snails received the yoked control No. 1 procedure (C). In this yoked procedure (procedure No. 1), snails were first tested (Pre) and then on the next days received the yoked-training procedure (filled squares). As can be seen in A and B, there was learning and memory in both of the operantly conditioned groups. In the yoked control cohort there was no significant difference in the number of attempted openings in the pre- vs. the posttraining session. Furthermore, the number of attempted openings in the posttraining session of the yoked control snails was significantly greater than the number of attempted pneumostome openings in the savings-test session (Session 6) of A and B. As a further control, each of the cohorts was challenged with a CC. Notice that in the operantly conditioned cohorts (A and B), there was a significant difference in the number of attempted pneumostome openings in CC compared to Session 6, which was not the case with the yoked control snails. Finally, when all three cohorts were again tested (Session 8 for A and B and Post 2 for C) with the standard context test, there was no significant difference in the number of attempted pneumostome openings in this test compared to the savings test (Session 6) in the operantly conditioned cohorts (A and B). There was however, a significant difference in the number of attempted pneumostome openings in Session 8 compared to the postsession in the yoked control group. As this postsession 2 was given 2 h after the first postsession test, this may indicate that these snails are now forming an association between pneumostome openings and the contingent presentation of the tactile stimulus.