On the left side of the figure, a rat is depicted during the Training or Sampling Trial (T1) where two identical objects are explored, typically for 3-5 min or until a set amount of exploration is obtained. An inter-trial delay is given, and then, shown on the right side, the retention or testing trial is given (usually for 3–5 min). If one identical object is replaced with a new object, this is the novel object recognition (NOR) protocol. If one of the objects is moved to a new location, this is the novel object placement (NOP) protocol, a spatial memory task. Hormones or drugs can be given pre-training (hours or days) to assess genomic changes or immediately post-training or up to two hours later in order to asses rapid changes. Post-training injections test effects of agents on memory consolidation.