O spatial landmarks in the room, a checkerboard pattern was placed in front of the target arm. () TgH1aV.Fb mice ( = 12) did not differ from wild-type ( = 9) during task acquisition and learned the task at similar speed and rate as the wild-type. () Both genotypes reached an asymptotic level of performance that was significantly better than their respective performances during the first training block. () After a 5 weeks break from training, the mice were retested in retrieval sessions. Both genotypes showed similar reduction in performance between the last testing block of the acquisition phase and the first block of the retrieval. () After the mice relearned the task, they were tested in a new room to control for the spatial cue dependence of the mouse behavior. The maze was arranged in the same orientation along the poles, but this time had new landmark cues in the new location. Success rate in the new room was at chance level for both genotypes.Copyright information:Taken from "Select Overexpression of Homer1a in Dorsal Hippocampus Impairs Spatial Working Memory"Frontiers in Neuroscience 2007;1(1):97-110.Published online Jan 2007PMCID:PMC2518050.