Fig. 7. Increasing RPeD1 impulse activity did not augment long-term memory formation in operantly conditioned preparations. (A) In conditioned and naïve preparations RPeD1 was depolarized (i.e. by injecting positive current) for up to 20 min immediately after the completion of session 1 (and after saline level had been raised). (B) Sample recordings in which RPeD1 impulse activity was increased in conditioned and naïve preparations after the completion of training session 1 (arrowheads denote the time of the depolarizing current injection in B and C). (C) Only the conditioned preparations significantly reduced their number of attempted pneumostome openings between sessions 1 and 2 (learning; t=2.477, P<0.05), but not between session 1 and the memory test 18 h later (LTM; t=1.012, P>0.05).