Experiment 2.

<p>Animals learned to access their daily feeding in a cage by running through a runway maze attached to it. A. Latency to eat. B. Eating time. C. Total 50-kHz calls in the runway maze. D. Total 50-kHz calls in the cage. The dashed line indicates that a maximal latency time was set at 240 s. Control vs. reward: * <i>p</i><.05, ** <i>p</i><.01. FD vs. FAL: ++ <i>p</i><.01. Day 1 differed from days 5 and 7 in reward rats: § <i>p</i><.05. % Day 1 differed from days 3 to 7 in reward rats: § <i>p</i><.05. Days 1 and 3 differed from day 7 in both groups: & <i>p</i><.05. Day 7 differed from days 8 to 10 in reward rats: # all <i>p</i><.05. Day 7 differed from days 8 and 10 in both groups: x all <i>p</i><.05. Data are expressed as mean+SEM (control = 10, reward = 20).