My day in Professor Williams’ lab varies by the mice schedule, but this week was especially busy. The project that I’m working on involves exercising mice (on wheels ~8hours/day every single day!) and memory test using a Barnes Maze (a circular table with 20 holes on the edge; mice have to find the right and only hole that leads down to a small, dark room which makes them feel safe and relatively comfortable compared to the brightly lit room).
This study is an 8 week project, and out of 16 mice that we have, half of them are on wheels for ~8hours/day and half are left sedentary. During week 1 and week 6, we test mice’s spatial memory (in order to see the effect of running/lack of running on their memory) by giving them 3 trainings followed by a probe test. We do the 3 trainings (on one and same hole on the Barnes Maze) in the span of 3 days (1 training per day for 3 days) and give them the probe test 1 hour following their last training. During the probe test, we test their memory by not placing the little room under the same hole that they were trained on for the past 3 days, and record the first time of their approach to the right hole along with how many times they approached what quadrants on the maze (in the span of 30 seconds).
Since we have 4 cages of mice (4 in each cage), in the morning we trained/tested cages 1 and 2 and in the afternoon, 3 and 4. We just finished week 1 training/testing this week, and also weighed them for the first time. I was quite surprised by their weights; the ones on the daily running wheels were about 2 grams slimmer than the sedentary ones (~18g vs. ~20g on average!). Also, the mice that we’re working with are all female, so we swab them during their estrous cycle to keep record of their secretion.
During the weeks when I don’t need to give mice training/testing on the Barnes Maze, my daily task is putting the appropriate mice in their running wheels from ~9AM to ~5PM everyday, even during the weekends. This still happens during the training/testing week, but they just get less running.
You’ll be surprised by how much the running mice actually run everyday. It is voluntary running, and during 9AM-5PM, they are placed in a different, larger cage with the disk-like wheel where they have access to large areas for rest, food, and water. We keep track of the number of wheel revolutions that these mice run everyday, and on average, they run about 6000~7000 revolutions on the wheel, which is roughly about .6 miles!
Although the training/testing procedure is quite long (takes about ~4.5 hours to get through all 16 mice), I do enjoy working with mice. Some of them are less obedient and cooperative than others, but I’ve been handling them for a bit more than a week, and they are starting to like me more and more. I hope the rest of the project goes well, and I can’t wait to see the results after I am finished with the experiment!
