Reverse Morris water maze learning and memory in 8- and 12-month-old wild-type and AβPP-PS1 mice.

<p>Spatial learning with an extra episodic memory component was measured in a 2-day acquisition phase, by determining the latency to find a hidden platform in the SW quadrant. Spatial memory was tested in the probe phase in which the percentage of time spent in the target SW quadrant was measured and the total number of platform crossings (where formerly the platform had been located). A: Both 8-month-old wild-type (n = 14) and AβPP-PS1 mice (n = 10) showed a decrease in latency during training. Overall latencies did not differ between the genotypes. B: During the probe trial, the 8-month-old wild-type and AβPP-PS1 mice traveled a similar distance. C: No differences were observed between the 8-month-old mice in the percentage of time spent in the target SW quadrant, although only wild-type mice deviated from 25% chance performance level. D: No differences were observed between the 8-month-old mice in the frequency of platform crossings E: Only 12-month-old wild-type mice (n = 9) showed a decrease in latency during training. 12-month-old AβPP-PS1 mice (n = 7) did not improve their performance during acquisition. However, overall latencies did not differ between the genotypes. F: During the probe trial, the 12-month-old AβPP-PS1 mice traveled a slightly longer distance than wild-type animals, although it did not reach statistical significance, # trend <i>p</i> = 0.066. G: 12-month-old AβPP-PS1 mice tended to spent less time in the target SW quadrant, although it did not reach statistical significance, # trend <i>p</i> = 0.066. Only wild-type animals deviated from 25% chance performance level. H: 12-month-old AβPP-PS1 mice crossed the exact former platform location less often than wild-type animals, *<i>p</i><0.05.