HINTS ABOUT BEHAVIORAL TESTING
Statistically significant effects of genotype on behavior often require at least 12-15 mice per genotype or 10-12 rats per experimental group to detect. Be prepared to have plenty of animals tested.
Age can exert a major influence on behavior. It is typically a good idea to have animals tested after they reach adulthood (90 days of age in rats and mice), unless you expect an effect to expressed early or late in development. Make sure that the animals to be tested are relatively close in age (after 90 days of age, one has more latitude).
For studies of knockout or transgenic mice, it is always best to compare genotypes within litters. This approach controls for the influence of background genotypic differences between litters and age. Animals from different litters and of different ages can introduce a lot of "noise" into the results. Be aware, however, that if all testing is performed on one litter, then the behavioral effects of "genotype" may not be generalizable to transgenic or knockout mice from other litters.
The sex of an animal, like age, is a major determinant of its behavior. Make sure that the number of males or females in each experimental or genotype group is constant across groups. Otherwise, we may be comparing sex effects as opposed to group effects.
It is probably best to group-house animals (Its certainly cheaper from a per diem perspective). Individually housed animals tend to be more skittish and react differently in behavioral tests in comparison to group housed mice.
Be aware that the background strain of your mice (or rats) will affect performance. Mice with any DBA, CBA, or 129sv genes are typically poor performers in some learning and memory tests. C57Bl6 mice are better performers in many of the same tests. If you suspect that a gene knockout will impair memory, you may want to use a purer C57 strain. If you expect that overexpression of a gene or transgene will improve memory, you may want to consider using a purer 129sv or DBA mouse. If such suggestions are impractical, dont despair, there are tests within each of our testing batteries which are useful for examining most mouse strains.
We are excited at the prospect of examining behavior via conditional gene expression. The ABC staff will work with investigators to ensure that drugs or compounds needed to turn on/off genes are provided to animals in the appropriate way during their stay in ABC housing facility.
Many investigators read about really cool behavioral tests that are performed in rats, non-human primates, or even in people. It is not necessarily the case that: 1) a mouse can even perform the same task or, 2) there is an analogous task for mice to perform. The ABC staff will work with investigators to choose or design tasks which are most similar to relevant tasks used for other species, but bear in mind the above-stated caveat.
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