Fig. 5. Operantly conditioned sham controls demonstrated learning, but not LTM. Conditioned sham controls were conditioned preparations (two sessions only) in which RPeD1 was impaled by an electrode but was not hyperpolarized, in order to determine if impaling the soma of RPeD1 with sharp electrodes affected the preparation's behaviour. (A) The soma of RPeD1 was impaled for up to 20 min immediately following the completion of training session 1. (B) Sample recordings of RPeD1 impulse activity recorded in conditioned and naïve preparations after the completion of training session 1, after the saline level had been raised. (C) Impaling RPeD1 with sharp electrodes did not affect behaviour, since the conditioned sham preparations still showed learning between session 1 and 2 (t=2.818, P<0.05), but no LTM was formed (t=0.8309, P>0.05). Within C, arrowheads denote time of electrode insertion. ^*P<0.05.