Figure 2.

Experiment 1: The impact of manipulating the amount of reward during encoding of the spatial memory task. (A) Schematic representation of the protocol in which the rats dug one sandwell to find three pellets or one pellet as reward (memory encoding) and received a nonrewarded probe trial 1 h or 24 h later (retrieval). (B) Memory was effective with three-pellet reward at 1 h and 24 h. When only one pellet was available at encoding, memory persistence decayed from above chance at 1 h to chance at 24 h. (C) Spatial memory after encoding with no reward (i.e., no pellets) was maintained at 24 h by the exploration of a novel box 30 min after encoding.