Lockbox enrichment
Lockboxes are mechanical puzzles consisting of one or more locks/mechanisms. The puzzles can be baited with a food reward (e.g., for mice, an oat flake can serve as food reward). To access to the food reward, the locks/mechanisms must be successfully opened. If the lockbox contains multiple locks/mechanisms, the animal must solve them in the correct sequence in obtain the food reward.
Lockboxes have been developed for a variety of species, including cockatoos, pigeons, keas, corvids, and great apes, to investigate sequential problem-solving abilities. In laboratory mice, lockboxes facilitate both manipulate and cognitive activities (1), which are often restricted in standard laboratory environments due to the limitations in space, complexity, and stimuli. These restrictions can negatively affect animal welfare, potentially compromising the quality of research data. In an extensive phenotyping study, lockbox enrichment was shown to have beneficial effects on the affective state of young adult female C57BL/6JCrl mice and enhance their performance in solving lockbox tasks (1). Moreover, the lockbox enrichment did not affect the relevant phenotype of the mice (i.e., state anxiety-related behavior, physiological variables, such as bodyweight, resting metabolic rate, stress hormone metabolite concentrations, adrenal gland weights) or the relative variability of the data (1)—an important consideration for researchers.
The 3D printing files for the lockboxes are available open access (2), allowing everyone to easily produce lockboxes at their own facilities.
References:
1. Hohlbaum K, Andresen N, Mieske P et al. Lockbox enrichment facilitates manipulative and cognitive activities for mice [version 2; peer review: 2 approved]. Open Res Europe 2024, 4:108 https://doi.org/10.12688/openreseurope.17624.2
2. Hohlbaum, K., Andresen, N., Boon, M. N., Kahnau, P., Mieske, P., Sprekeler, H., Hellwich, O., Thöne-Reineke, C., & Lewejohann, L. (2024, Mai 8). Mouse Lockboxes - 3D printing files and videos (v1.0.0). Zenodo. https://doi.org/10.5281/zenodo.11143666
