Figure 1.

Spatial learning task. A, Procedure of the fMRI experiment. After a familiarization phase outside of the scanner, eight retrieval phases, each comprising eight navigational retrieval trials and four control trials, alternated with seven encoding phases during scanning. In the behavioral experiment, the structure was the same except that 12 navigational retrieval trials per learning block were completed while the control trials were omitted. B, Layout of the VE. The VE resembled a typical German historic city center and consisted of four interconnected intersections (I1–I4) that could be reached from four directions (D1–D4). At two intersections, a town hall (T1) and a church (T2) were placed at the end of one of the outgoing streets that served as target landmarks in the navigational retrieval trials. Yellow arrows exemplify one encoding tour that started from one of the target landmarks in clockwise or counterclockwise direction (a short segment of one tour is shown in Movie 1). C, Structure of one example navigational retrieval trial to measure spatial learning. After fixation, participants were passively transported toward one of four intersections in the VE starting from one of the four streets leading toward that intersection (see Movie 2). Movement stopped at the center of the intersection, a red crosshair appeared, and participants were asked to move the crosshair in the direction of the respective target landmark. During the entire duration of the trial, a picture cue of the target landmark was displayed at the bottom of the screen, and the background was obscured by fog to prevent seeing the target landmarks. In the fMRI experiment, an additional jittered interval of 1 s (still phase) was added after the travel phase/before the crosshair appeared on screen.