Test group
-5xFAD female 4 month-age Tg (n=8)
-5xFAD female 4 month-age Non-Tg (littermate of Tg) (n=7)
(Amyloid beta is only generated in Tg mouse, not Non-Tg)
Behavior test
-Morris Water maze
- Contextual fear conditioning test
Result
-In both tests, Non-Tg mouse behavior is worse than Tg.
Questions
-What could affect these unexpected result? I expect that Non-Tg Behavior is better than Tg.
-I suspect that their father and mother age were old when mating (5 month-age).
This could be a great, albeit controversial finding, but you need to make sure all of your procedures and data are in good order before you can challenge existing literature (you might consult Alzforum- https://www.alzforum.org/research-models - for a convenient summary of other work).
Some data that would help address your question include, (this is not an exhaustive list)-
- What age were these animals (5xFAD are reputed to begin manifesting cognitive changes between 3 and 6 mo , even after that age, n's of 13-15/ group are needed). So you will immediately get the criticism that your experiment is under-powered (although with half of your study completed and the averages pointing in the wrong direction, it is hard to envision how the second half of the animals would fix this).
- Are these animals on a B6SJL or a C57BL6 background
- Are these males or females or a mix of both sexes
- What measurement outcomes are you using to inform your conclusion (e.g., in water maze, is it path length or latency, is it during training (if so, across all days, only from one day, only from one session) , is it # platform crossings on the probe trial, etc).
- For results, what is the effect size/z-score ([difference in the means]/standard deviation), what are the means +/- SEM for each of the groups?
- Did you do visual cue assessment to determine if any of the mice were blind, did you check for thigmotactic behavior in the water maze? In mice, radial arm water maze may be a preferred procedure compared to Morris water maze.
Eric M Blalock I sincerely appreciate your informative response.
As I mentioned above my
5xFAD mice are
-female
-4month-old
and B6SJL background and no blind which were confirmed by genotyping and visual test.
As you mentioned, I will consider the total mouse numbers and other behaviour tests.
Thanks again,
Depening on what your actually readout is, 4-month-old 5xFAD TG mice do not show any behavioral phenotype compared to non-TG littermates at that age.
I could not even detect differences in older (7-month-old) mice. We usually dectect first behavioral differecnes in 10-12 month old females in the Morris water maze, but this is highly dependent of the setup and experimental procedure.
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Steffen Storck Thank you for your response. As you said, I found another paper which show that 5xFAD behavioral abnormality, proven by morris water maze start from 9-month old.
Behavioral and EEG changes in male 5xFAD mice; F.Schneider, K.G.Reymannab, Physiology & Behavior 2014
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