Figure 1.

Behavioral apparatus and testing environment. (A) Radial maze in a testing room with distinct visual cues. (Inset) Two objects, a LEGO block and a Spider-Man, positioned over left and right food wells, respectively, in the choice platform. The transparent partitions between food wells were to encourage discrete choices between objects. (B) Spatial paired-associate learning task. Illustration of the radial maze (overview) is given with four arms (arm 1, 3, 5, and 7 clockwise) used in the task in gray color. Arms 1 and 5 (lighter gray) were used for object–place paired-associate trials and arms 3 and 7 (darker gray) were used for location–place paired-associate trials. Possible configurations of objects and appropriate choices are provided for individual arms (e.g., LEGO block results in reward in arm 3, regardless of its position in the choice platform) all together for illustrative purposes only. In each trial, only one arm was accessible and objects were available only in the open arm.