Mouse water maze hints from Dr Roger Morris

"A delicate balance of motivation provided by stress/reward, and a difficult task."

In 1998 Dr Roger Morris (not to be confused with Prof Richard Morris, who invented the maze) shared his hard-won notes on running mice. They're practical, a little funny and still very useful. We've split them into short pages; here's how they begin.

From the original watermaze.org (1998–2013)

Mouse / Water maze Hints

12/98. Copyright (C) 1998 RJ Morris & HVS Image.
The following notes are edited from material kindly supplied by Dr. Roger Morris.

Editor's notes:

“a) Rats are natural swimmers and if handled well will cooperate easily in Water Maze. They don't have the option to float or jump - they are solid citizens who just swim for that platform and get onto it.
b) Mice are also good swimmers, and if handled well, will also take part easily. But they are more temperamental, and they do have the option to stop swimming and just float, and to jump. These notes suggest ways to reduce stress, so your mice will feel confident, and cooperate.
”
-Richard Baker

Introduction

The swimming-pool (Morris Water Maze) is a delicate balance of motivation provided by stress/reward, and a difficult task. It is an unnatural for rodents, for whom sight is a minor sense. If the stress is too high, or the reward too slight, the task is not attempted.

Platform & waterMesh on the platform, 5 mm of water and an accurate 24 °C.
Time on platform & rescueTen seconds on the platform, and why rescue is the reward.
Cues for miceCues placed and designed for a mouse's eye view.
Time & intervalsSwim length, two or four trials a day, and 30-minute intervals.
Handling & acclimatisingTwo days of getting to know you, and no perfume.

For tracking small, fast animals, see what you can do with HVS Image.