Figure 1. Behavior on the spatial delay discounting task.

A: Task layout. One side provides a larger reward (3x) after a delay D; the other side provides a smaller reward (1x) after 1s. The delay is adjusted as a function of the animal's decisions. B: Delay on the adjusted delay side by lap. Red indicates laps to the delayed side, increasing D by 1s; blue indicates laps to the non-delayed side, decreasing D by 1s. Small dots show LR and RL laps; circles show LL or RR laps. Behavior reveals three phases: investigation, titration, and exploitation. B1: upward titration; B2: downward titration. C: Gray dots show all sampled positions in a given session, with a single lap in red. VTE can be measured quantitatively with zIdphi (see supplemental methods). C1: VTE pass (zIdphi =6.05); C2: non-VTE pass (zIdphi =−0.13). D: zIdphi distributed in a skewed manner, but can be separated into VTE events and non-VTE events. The threshold between VTE and not was set at zIdphi =0.5, the point where the observed distribution diverged from the expected normal distribution (see supplemental methods). E: VTE decreased in the exploitation phase. Bars show interquartile range, line shows median, notch shows standard error of the median. F: Calculated distance between paths (see supplemental methods). Paths became more stereotyped with time. Early laps are distant from each other as well as from the later laps. Later laps are more stereotyped, marked by a lack of distance between the paths.