Mouse handling for the Mobile HomeCage

Handling is an important part of mouse training in preparation for the experiments in the Mobile HomeCage.

The following recommendations are the highlights from a mouse handling workshop by Dr. Bogna Ignatowska-Jankowska, a behavioral scientist and a ”mouse whisperer”, who trains mice by capitalizing on their natural tendencies and avoiding unnecessary stress and punishment.

Bogna’s research at the Okinawa Institute of Science and Technology (OIST) is supported by Japan Society for Promotion of Science (JSPS). Bogna is affiliated with Prof. Marylka Uusisaari’s lab at OIST, which studies neuronal rhythms in movement.

 

Bogna’s DO’s and DO NOT’s of mouse handling

Make it simple. Familiarize the animal with the experimental conditions introducing one variable at a time. In the case of the Mobile HomeCage, start with the experimental room, then the cage and the noise produced by the air source. Make breaks between introducing new variables or tasks to allow time for memory consolidation. Be careful not to introduce new variables unintentionally: if you must wear a perfume or eat smelly foods on the first day of training, be prepared to do so on all remaining days.

Project calmness. Do not express fear, anxiety or stress as these emotions will transfer to your test animals. Suppress your reflexes such as involuntary hand jerking or screaming. Feel free to talk to your mice in any language, as long as your voice is calm and warm. Learn to control yourself before you can train the mice.

Project dominance. Do not hesitate, do not submit to animal’s will, persevere.

Increase the number and reduce the duration of handling sessions: five 1-minute sessions are better than an hour-long session. Make breaks for rest and memory consolidation.

Build trust and enhance the comfort level. Treat mice exta-nicely, so that withholding such treatment would be perceived as punishment (”behavioral punishment”). Use food or drink deprivation only as a last resort.

Do not lift mice by the tail without leg support as not to increase their stress level unnecessarily. In fact, do not lift their feet off the ground for more than a fraction of a second.

Do not let go of the tail, if you don’t trust the animal.

Do not reward with foods or liquids that are not part of mouse natural diet as this may affect their metabolism and – by extension – behavior.

We could not help but notice that much of  Bogna’s advice would just as well apply to parenting! Feel free to use it outside the lab.

 

Handling techniques

As with many things in life, there is more than one way to handle mice. Choose the technique that is right for your “furry customer” and for you.

Most of the below techniques apply to any situations that call for mouse handling. Scroll down to the last video for the the handling techniques specific for the head fixation in the Mobile HomeCage. Note: the videos below have no sound.

Tube. Use a familiar tube, as not to introduce a novel object during training. The tube makes the training more fun for the mouse and protects against mouse bites. Direct the tube towards the mouse and gently push the mouse’s back:

 

Forearm. This technique works with both novice and already trained mice. Hold the mouse by the tail and pull it onto your forearm:

 

Back of palm. If you suspect your mouse might bite, use the back side of your palm. Do not lift the mouse up into your palm. Instead, “sink” your hand into the cage:

 

Palm. Your palm, when it’s calm, feels like a nest to the mouse:

 

Palm rotation.  It is possible to use just one hand to pick up the mouse:

 

Scooping is the fastest and friendliest way to lift a mouse:

 

Scruffing works great for an i.p. injection or a belly inspection. Use it for 100% safety and control:

 

Restricting head-movement is specific for training prior to head-fixation. Hold the mouse by the head plate to control its head movement. Gently but firmly pull the mouse by the head plate and guide it in a certain direction, e.g. up and down your forearm. Expect some resistance initially. It is less stressful for mice to get the first experience with head restrain in your hands rather than in the clamp:

 

If you want to keep the mouse in a certain place, such as your palm (or eventually a low-wall floating cage or even a disc), gently tap on the nose or pull the mouse back by the tail to prevent it from escaping.

Proceed to train the mouse in the Mobile HomeCage only when the mouse is calm, comfortable being held and does not try to escape.