We started with fear conditioning! Week 4 focused on cohort 1 and week 5 focused on cohort 2, giving each cohort a week off experiments to rest.
This was my first time performing a more stressful test on mice. The first day of cued fear conditioning involves placing each mouse in a chamber with an established baseline context and they are exposed to neutral conditioned stimuli (neutral cue) alongside an aversive stimuli that they learn to associate together. I want to acknowledge that this felt more emotionally charged than any other test I’ve done (as explained in earlier posts) because the responses to the aversive stimulus were audible, which made the experience more difficult at times and added an emotional component to the work. The following days were focused on fear recall, in which the neutral cue was presented to the mice without the aversive stimuli. This test evaluates the strength of the learned fear by tracking the behavioral responses (in our case, a mouse standing completely still or “freezing” is used) when the neutral cue appears alone. More freezing responses indicate stronger fear learning.
The first day for each cohort was very quick. Each mouse was in the chamber for 5 minutes, and while it took some time to get used to working with the new equipment and cleaning up, both cohorts ran smoothly! However, for both cohorts, the recall days took much, much longer. Each mouse had to be in the chamber for about 30 minutes, and while they each followed the same routine, the repetitiveness could get a little boring at times, especially after spending 30+ minutes on each mouse, including cleaning.
These two weeks were much more independent; I was grateful to be able to run all of the experiments by myself after being shown how to use the equipment on the first day. Spending 8+ hours in the lab by myself allowed me to experience what research would look like and this is when, despite the moments of boredom, I decided this was something I want to keep doing!
I want to thank Lina, who took over the analysis of this set of experiments to keep things consistent. For some context, the analysis for fear conditioning uses a software that requires the lab member to review each video, of each mouse, and set a threshold for what they consider “freezing”. Thus, it made sense for Lina to do this aspect of the work.
Anyway, that is it for my past two weeks at the Bygrave Lab, it’s crazy how fast these weeks have gone by! But I am excited to say that I will be continuing my research over the fall semester.
Thank you all for reading :-)