We salute you: A novel spatial learning and memory test for mice

Rationale and Apparatus Design

Mouse models (Mus musculus) are essential for neurological research, yet many traditional cognitive assays (e.g., the Morris Water Maze) were optimized for rats and rely on ethologically irrelevant or highly stressful conditions (e.g., swimming, food deprivation, aversive light/noise). The Colosseum Maze addresses this limitation by being specifically tailored to the innate shelter-seeking behavior of mice, utilizing a large, open space and ambient light as sufficient motivation without external aversive stimuli. This approach mitigates stress, promoting a more accurate assessment of intrinsic spatial learning and memory.

Validation in Wildtype Strains

Validation studies confirmed the apparatus’s efficacy across common wildtype research strains (C57BL/6NTac (B6), B6 x C3H F1 hybrid, and 129SvEv).

1. Locomotor Activity and Anxiety: Initial habituation to the open-field protocol showed significant differences in basal locomotor output (distance and velocity) between the three wildtype strains. However, all three strains demonstrated the ability to readily perform the Colosseum Maze task, indicating that differences in baseline exploratory behavior did not preclude successful task acquisition.
2. Learning Acquisition: Across all training phases (1-door, 6-door, and 8-door configurations), escape latencies and distance traveled decreased significantly, confirming that wildtype animals successfully learned the spatial location of the escape box. The observed performance differences between strains suggest the task is sensitive enough to capture strain-dependent cognitive variability.
3. Use of Distal Cues: To confirm that mice were navigating based on true spatial cognition rather than localized features, a 90-degree arena rotation validation was performed. The lack of a significant difference in escape latencies before and after the rotation validated the reliance on distal room cues for navigation, establishing the Colosseum Maze as a robust measure of allocentric spatial memory.

Applicability in Disease Modeling

The Colosseum Maze was further validated using the 5xFAD mouse model (Jax: MMRRC Strain #034848-JAX), an established model of Alzheimer’s disease known to exhibit deficits in tasks like the MWM.

1. Cognitive Deficit: Compared to wildtype littermates, 5xFAD animals displayed significantly greater escape latencies and greater distances traveled across all training phases, indicating a clear deficit in spatial learning acquisition.
2. Motor Function: While 5xFAD animals had a significantly lower velocity of travel during the maze trials, they showed no difference in basal locomotor output or anxiety-like behavior compared to wildtype littermates during the initial Open Field habituation phase. This suggests that the observed deficit in the Colosseum Maze is primarily cognitive, consistent with findings in other spatial memory tasks.

Conclusion

The Colosseum Maze is a validated, ethologically relevant spatial learning and memory test for mice. It demonstrates high sensitivity by capturing both strain differences and cognitive deficits in the 5xFAD model, while minimizing stress artifacts inherent in traditional rat-centric assays. The task’s ability to engage mice without severe aversive stimuli offers a significant methodological improvement for cognitive phenotyping in preclinical research.