Protocols
Learning to find the platform
From swimming round the wall to heading straight for the platform.
Watching an animal learn the water maze is one of the quiet pleasures of behavioural neuroscience. In the first trial it swims along the wall, hoping for an exit. Then it starts to explore the middle. Eventually it bumps into the platform, climbs on, rears and looks around. A few days later, it swims straight there from wherever you put it in. The original notes describe that journey beautifully:
Learning
At first the rat will swim around the side. After a while it understands there is no way out by doing that. Then it searches more to the center. If it does not find the platform after approximately two minutes, lift it out & dry it. If it really does not get the point, you can gently guide it to the platform. It gets on the platform & usually rears and looks around. This is something else to learn, that there is an escape platform. You can leave it for ~ 15 seconds, to orientate. It is looking into the room.
There must be visual cues on the room walls. It needs at least 3 different cues, e.g. 3 different posters, (so it can 'triangulate'), always visible from inside the pool. These cues should be extra-maze i.e. well outside of the pool. If they are close to the poolside, then the rat could be doing association between the cue & the platform. After some training swims, the rat will go direct to the platform. After ~15 seconds you lift it off the platform and gently dry it (better - put it in a litter of tissues, so it can dry itself). Rats can do several swims per day. Now you can use a different start-point. An informed rat does not try to back-track to the old start point. It goes direct to the platform. Because it has a spatial map in its hippocampus? The training sequence and test sequence are something that you as the scientist have to decide on. Obviously you are going to use Controls and Experimental rats.
Original text: watermaze.org Part I, General Information. From original material by Richard Baker. Reproduced unchanged. Copyright Richard Baker© 2013. All Rights Reserved.
: An informed rat does not try to back-track to the old start point. It goes direct to the platform.
That last line is a lovely test of whether learning is spatial: change the start point, and see if the animal still heads for the platform. More on that in start positions and release.
Learning curves are usually plotted from escape latency and path length.
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