Fig 4. Object space task mouse: 4-week overlapping training.

A Panel: Trial structures for the 4-week version of the overlapping condition (object identity changed from trial to trial). Across the 4 weeks, 1 location remains constant across all sample trials and the test trial, the second location varies (5 trials per day, 5 days for the first 3 weeks). The first trial on Monday in week 2 (trial 26) as well as the final trial on Wednesday in week 4 (trial 76) function as 3-day and 5-day test trials, respectively. The stable location was counterbalanced across animals for each condition as well as within an animal across conditions to avoid general place preference effects. B Panel: Exploration time remained stable across the 3 weeks (P = 0.96). C Panel: The DI remains stable with preference for the less often shown location across the 3 weeks (P = 0.5). D Panel: Test to control for episodic memory effects the locations in the last sample trials and in the tests trial are equal. Both 3 days and 5 days after training, the animals showed a significant cumulative memory effect, with preference for the less often shown location (*P = 0.033, **P = 0.008). E. DI of each trial for the whole 4-week period. Data in S4 Data. DI, discrimination index.