Figure 5.

Cooling can extend the memory for extinction training. Twenty-six animals received three 45 min operant conditioning sessions (TR1 and TR2 were administered on the same day 1 hr apart, followed by TR3 on the next day). One hour later, animals received three 45 min extinction sessions (E1 and E2 were administered on the same day 1 hr apart, followed by E3 the next day). One hour later, all animals were immediately placed in prechilled 4°C water for 22 hr, after which they were transferred to room temperature water. Two hours later, animals were tested for savings. Animals still showed memory for extinction training when they normally demonstrate spontaneous recovery for operant conditioning (Fig. 2). TS was not significantly different (p > 0.05) from TR1 and was significantly higher (p < 0.01) than TR3, thus not meeting the criteria for operant memory designation. (ANOVA; F_{(25, 2)} = 46.8073; p < 0.001).