Mice vs rats
Rats in the water maze
"Solid citizens" who just swim for the platform.
The water maze was first developed with rats, and the original notes have a soft spot for them. Here are the two sections on rats, unchanged, including the photo of a black pool with clear water.
The Rodents
We think that the best rats are hooded. These are the same as those used by Morris. Hooded rats are easy to track. The tracker detects the black hood. HVS is like other systems, it tracks contrast. For the same reason, dark-colored mice track well. Your pool and platform are white. You make the water white, e.g. with skim milk powder (this is to stop the rat from seeing thru the water). We think that hooded rats perform better than white (albino) rats, possibly because albino rats do not see as well. Another problem with albino rats: to get contrast for tracking, the pool has got to be black with clear water. Black pools cause tracking problems, because they reflect lights. But it can be done. (See set-up hints in this document). There is an (escape) platform. This is white (or clear Plexiglas) for a white pool. During the training phase you can allow the platform to be ~ 1/2" above the water, and you can paint the side black. This trains the rats, that there is a platform, and that is how to get out of the water. This is important - they have got to know this before any place-learning can happen. When you put the rat into the water, support it in the hand and gently lower it into the water with the tail-end lower, so the head does not go under water. Dropping them in head-first stresses them, which impairs learning. Usually they are put in with the head pointing towards the pool-side, to minimize bias.
Original text: watermaze.org Part I, General Information. From original material by Richard Baker. Reproduced unchanged. Copyright Richard Baker© 2013. All Rights Reserved.
Temperament!
Rats are solid citizens. They are quite willing to swim to that platform, get on it, and orientate. Mice are also natural swimmers, but they are altogether more frisky & temperamental - this is covered elsewhere in the HVS Image Mouse Notes.
Original text: watermaze.org Part I, General Information. From original material by Richard Baker. Black pool with clear water with thanks to Dr Hayde Bolouri, Neuroscientist, Institutionen för neurovetenskap och fysiologi, University of Gothenburg. Reproduced unchanged. Copyright Richard Baker© 2013. All Rights Reserved.
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