In this Perspective, the authors summarize the current knowledge on the post-COVID-19 condition, focusing on the neurological manifestations, and discuss the applicability of existing animal models to recapitulate human condition.

Poor replicability in animal research can be a result of low external validity driven by rigorous standardization of study populations. This study investigates how heterogenization of study populations by using mice from different breeding sites might affect the replicability of animal studies conducted in a single facility. The findings suggest that heterogenization by breeding site has limited capacity to improve replicability in animal research.

The 3R principles provide an ethical framework for animal research throughout the world. However, despite the increasing awareness of these principles, there is still a lot of room for improving their implementation, especially when it comes to reduction. By combining Bayesian statistics with a shift in experimental design, here we present an entirely new idea to reduce animal numbers within experiments.

Researchers have developed a cost-effective, noninvasive method for determining torpor-bout duration in heterothermic mammals. They used the paper towel shredding behavior of ground squirrels to detect 59 arousals with 100% accuracy over 52 days. This method avoids the drawbacks of other cheap monitoring systems such as the sawdust technique.

The authors defined rat microbial biogeography by re-analyzing publicly available RNA sequencing data from 11 organs of juvenile, adolescent, adult and aged Fisher 344 rats.

The study introduces an open-source, customizable 3D printable design for rodent conditioning for magnetic resonance imaging and other imaging modalities. The design is easy to use and can be applied to both anesthetized and awake mice, and anesthetized rats.

Poor replicability in animal research can be a result of low external validity driven by rigorous standardization of study populations. This study investigates how heterogenization of study populations by using mice from different breeding sites might affect the replicability of animal studies conducted in a single facility. The findings suggest that heterogenization by breeding site has limited capacity to improve replicability in animal research.

Environmental enrichment is a home-based intervention that mimics natural habitats for laboratory-housed animals. This systematic review of 27 environmental enrichment protocols finds consistent benefits for zebrafish welfare while raising the importance of a standardizing protocol to improve reproducibility of results.

The authors used a gene-editing approach to generate a C57BL/6J mouse model expressing the CD45.1 epitope. The model, which overcomes some of the issues reported with the congenic mouse B6.SJL, could be useful for adoptive cell transfer experiments.