Strains, eyesight and coat colour

Strain choice affects nearly everything: how well an animal sees the room cues, how anxious it is in water, and how easily the camera can pick it out. The original notes favoured hooded rats, partly because "albino rats do not see as well". Here's the fuller picture.

Questions people ask

Which mouse strain is best for the water maze or Barnes maze?

Choose a strain with normal vision, and check what is known about it in your test. C57BL/6J and 129 substrains are commonly used; avoid strains that are blind as adults (for example C3H/HeJ, CBA/J, FVB/NJ) for visual spatial tasks. Your local ethics committee, licence conditions and vet always take precedence.

More detail

Three 129 substrains learned the water maze better than C57BL/6J [Clapcote & Roder 2004]. CD1 did better than C57BL/6J in the water maze but worse in the Barnes maze [Patil 2009]. Inbred strains differ widely in learning and anxiety [Crawley 1997; Upchurch & Wehner 1988]. Vision mutations: [Peirson 2018].

Going deeper

Even standardised strain differences can vary between labs [Crabbe 1999]: use a water and a land maze where you can [Patil 2009].

Sources: doi:10.1016/j.bbr.2003.09.030; Patil et al. (2009). Evaluation of spatial memory of C57BL/6J and CD1 mice in the Barnes maze, the Multiple T-maze and in the Morris water maze. Behavioural Brain Research 198(1):58-68. doi:10.1016/j.bbr.2008.10.029; doi:10.1007/s002130050327; Upchurch & Wehner (1988). Differences between inbred strains of mice in Morris water maze performance. Behavior Genetics 18(1):55-68. doi:10.1007/bf01067075; doi:10.1016/j.jneumeth.2017.04.007; doi:10.1126/science.284.5420.1670

Which rat strain should I use?

Most common rat strains can learn the water maze, so choose one that suits your research question and keep it consistent. Many strains work, including Sprague Dawley, Long Evans, Lister, F344, Wistar and Dark Agouti. Pigmented rats see better than albino rats, but albino rats can still do the water maze well. Your local ethics committee, licence conditions and vet always take precedence.

More detail

Most common rat strains can do the water maze, but they differ in vision and emotionality, so choose a strain for your question and keep it constant; strains used in the water maze include Sprague Dawley, Long Evans, Lister, F344, Wistar and Dark Agouti [Vorhees & Williams 2024]. Albino strains were slightly better in a swim maze, Long-Evans better at object discrimination [Andrews 1995]. Albino rats have about half the acuity of pigmented rats [Prusky 2002].

Going deeper

Strain differences may partly reflect emotional differences [Andrews 1995], so include swim speed and thigmotaxis in your analysis.

Sources: doi:10.1016/j.crtox.2024.100151; doi:10.1016/0031-9384(94)00336-x; doi:10.1016/s0166-4328(02)00126-2

How do strain differences in anxiety and activity affect results?

Anxious or less active strains may hug the wall or move less, which lengthens latency without any memory problem. Use cued trials, swim speed and thigmotaxis to check. Your local ethics committee, licence conditions and vet always take precedence.

More detail

Open field activity and anxiety-related responses differ between strains [Crawley 1997]; thigmotaxis and centre time reflect anxiety [Prut & Belzung 2003]; strains differ in stress responses [Patil 2009].

Going deeper

We found no single source ranking strains for swimming ability; check swim speed and the cued trial in your own animals.

Sources: doi:10.1007/s002130050327; Prut & Belzung (2003). The open field as a paradigm to measure the effects of drugs on anxiety-like behaviors: a review. European Journal of Pharmacology 463(1-3):3-33. doi:10.1016/s0014-2999(03)01272-x; Patil et al. (2009). Evaluation of spatial memory of C57BL/6J and CD1 mice in the Barnes maze, the Multiple T-maze and in the Morris water maze. Behavioural Brain Research 198(1):58-68. doi:10.1016/j.bbr.2008.10.029; doi:10.1016/j.crtox.2024.100151

Does my strain's eyesight matter?

Yes. Some common mouse strains are blind as adults and cannot do a visual spatial task. Check your strain before you start. Your local ethics committee, licence conditions and vet always take precedence.

More detail

The rd1 mutation is carried by C3H/HeJ, CBA/J and FVB/NJ; C57BL/6N carries rd8; DBA/2J develops glaucoma after about 9 months; albino strains have reduced visual function [Peirson 2018]. rd1 strains did not show spatial learning [Brown & Wong 2007].

Going deeper

Check your supplier's genotype data: substrains differ, and a mutation may be absent in some colonies [Peirson 2018].

Sources: doi:10.1016/j.jneumeth.2017.04.007; doi:10.1101/lm.473907

Coat colour and water colour decide how well an animal can be tracked; see why video track in the Morris water maze.

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