Animal Behavior Guide
Here are some tips to for using the miniscopes to run experiments on freely moving mice.
Plan you experiments schedule accordingly. Here is a typical timeline for getting mice ready for experiments in freely moving mice.
- Week 1: virus injection surgery
- Week 2: GRIN lens implant surgery
- Week 3: recovery
- Week 4: base plate surgery + acclimation to experimenters/handling
- Week 5: habituation to wearing miniscopes & setting imaging focal plane
- Week 6: begin experiment!
Acclimation to experimenters/Handling
We typically wait at least a day after base plate surgery to begin handling. We recommend that mice become well acclimated to the experimenters prior to mounting miniscopes on awake moving mice. It is important that the mice feel comfortable with the experimenters as stress during the mounting of the miniscope during the experiment can cause adverse effects for the mice and thus, experiment. After gently handling the animals a few times, acclimate the mice to getting something placed on and off their heads by gently taking the protective caps on and off their base plate (that is cemented on the mice's heads). The experimenters should be able to quickly remove the cap without much struggle from the animal before continuing onto the habituation phase.
Habituation to wearing miniscopes
Once the mice (and experimenters) are comfortable with the cap removal, habituate the mice to wearing the miniscopes while freely moving. To habituate, one experimenter should calmly hold the mouse and remove the cap, while the second experimenter replaces the cap with the miniscope. The miniscope should easily snap into place with the magnets. The second experimenter should gently hold the sides of the base plate with one hand while securing the miniscope with the set screw with the other hand. Especially during the first time, the animal may struggle. If the animal is struggling too much, let go and calm the animal. If the animal resists and struggles TOO much while you are holding onto the base plate, it can lead to the dental cement holding the base plate to come off the skull. When the animal is calm, try to hold the base plate and insert the set screw to secure the miniscope again. Once the miniscope is secured, let the animal explore your habituation environment of choice. We typically just let them move freely around in their home cage (even if there are other mice in the cage). Depending on your experimental demands, you will need to habituate to different levels of movement. If the experiment only requires mice to walk around and explore, we recommend habituating for at least 3 days for 10 minutes each day. If the experiment requires the mice to run swiftly (e.g. down a linear track), then we recommend habituating for at least 5 days for 10-30 minutes each day.
Setting imaging focal plane
We recommend to set the focal plane of imaging during the habituation trials.