Reproducibility in cancer biology, training rats for refined fMRI, and playpens for mice

The papers behind the pod:

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It’s the 3rd Thursday of January – happy new year! You’re listening to 3 Minute 3Rs, your monthly recap of efforts to replace, reduce and refine the use of animals in research. Of course, we focus on those three Rs, but many have suggested adding a fourth R to the list: reproducibility. Designing experiments with reproducibility in mind is a key aspect of reducing unnecessary animal use, as well as being good for advancing science.

In 2013 the Center of Open Science and Science Exchange began a collaboration to investigate the reproducibility of 193 experiments from 50 high-impact cancer biology papers. Over eight years of repeated experiments, they found that they could only reproduce 50 experiments from 23 papers, generally due to a lack of detail about the methods used or resources being unavailable. 15 of those 50 repeated experiments used animals, and while just over half of them at least partially confirmed the original results, the repeated results were not always statistically significant. Experimental design was also an issue: only one of the original animal experiments used randomization and none used blinding or calculated a sample size before the study began.

Papers describing these results are now available in eLife, with all the relevant data available on the Open Science Framework website and more Replication Studies to come from this collaboration. As the reproducibility crisis continues to rumble on, why not check them out and put designing more robust experiments at the top of your agenda?

Next, let’s look at how training rats can help make fMRI a less stressful experience.


Functional magnetic resonance imaging, or fMRI is a powerful non-invasive procedure that is used to assess brain function and connectivity. However, fMRI research in animals is often confounded due to the physical restraint and loud noises that occur during recordings as these induce stress which can alter information processing and cognition.

An article from Frontiers in Neuroscience describes a protocol for habituating rats to fMRI that also avoids the need for surgical head restraint. Rats were gradually trained via 18 sessions over 3 weeks beginning with basic handling phase. After following this protocol, fMRIs in awake rats were successfully conducted without inducing increased stress and still achieving stable images with very low motion artifacts.

To learn more about this rat refinement, read the full paper online.


Finally, playpens for mice – could they be a viable option for refinement when home cage space is limited?


Good environmental enrichment improves the quality of life for laboratory mice by providing increased opportunities to carry out natural behaviours such as running, climbing and burrowing. However, due to space requirements, cost and sanitation constraints many facilities worldwide still use standard housing, which has been associated with potential welfare problems.


In their publication in Scientific Reports, Ratuski et al show temporary access to playpens could be an effective method to provide mice housed in standard cages with space and structures to facilitate natural behaviors. In this study, female mice were given access to playpens three times a week for several weeks. Mice in the playpens were more active, compared to mice in conventional cages and over time, the animals entered the playpen more quickly and showed increased anticipatory behaviors before accessing the playpen. All indicating the mice found access to playpens rewarding. Want to learn more? Follow the link in the description.

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