Cued and hidden platform training

More on Morris Water Maze

12/98. Copyright (C) 1998 RA & HVS.
Our thanks to Dr Richard Anderson for this. Edited by HVS.

We can examine reference learning and memory in the Morris water maze. Initially the mice are trained to locate a cued, flagged platform. During this phase of the study both the cued platform position and the starting position of the mouse are randomly varied to avoid habituating the mouse to a particular area of the pool. Following this sensory motor test the cued platform is switched with a submerged platform the position of which is fixed for each mouse. As the mouse learns its position the path lengths and latencies to locate the platform are reduced. Following the final placed session, the platform is removed and the swim-pattern of the mice is tracked for one minute. We then compare the time the mouse spends swimming in the former platform quadrant with the time in the other three. This gives a measure of memory and also allows us to see if the mice are using different strategies to find the platform. For example, instead of using the distal cues, some mice learn to swim at a fixed distance from the edge of the pool until they find the platform. An additional HVS measure one can take includes the number of platform position crossings. Again if the mouse shows good evidence of spatial memory the mouse will exhibit a significantly increased number of former platform position crossings in comparison with the other three. A further advantage of this model is that by reversing the submerged platform position, it allows us to examine flexibility of learning, i.e. how easy is it for the mouse to let go of one learned behavior and acquire the new task. Inflexibility of learning is an early feature of AD dementia.

Original text: Dr Richard Anderson, December 1998, edited by HVS. Copyright (C) 1998 RA & HVS. Reproduced unchanged. Copyright Richard Baker© 2013. All Rights Reserved.