Figure 3. Rats time reward delivery on small reward but not delayed reward trials.

A. Line deflections indicate the time course of well entry and reward omission and delivery on delay and small reward trials (odor sampling precedes well entry but is not shown; see Figure 2A). Dashed lines show when reward is omitted (long-delay trials) and solid lines show when reward is delivered (delay and small reward trials). B. Licking aligned on omission (left) and delivery of reward (right) on delay (black) and small (gray) reward trials. Licking increased significantly before delivery of reward on small trials and before omission of reward on delay trials; licking did not change significantly prior to reward delivery on delay trials. C. Bars illustrating slope of rise in licking behavior during the 500 ms preceding reward omission and delivery on delay and small reward trials (*P < 0.0001; ttest). Error bars indicate SEM’s.