We are doing MWM with mice.
In my understanding, the experimenter should stand at the same location during all the trials of the place training， so that the mice will use the experimenter as a distal cue. But where should the experimenter stand? Suppose, the platform is located at SW, is it suitable if the experimenter always stand at SE? I'm afraid SE is too difficult for the mice, while SW is too simple.
I don't think it makes a major difference, as long as the experimenter stands at the same place every time.
How does the room look? Are there other major clues in the room, or is the experimenter the biggest clue?
If you stand at SW and close to the maze, it could be possible that the mice goes the opposite direction at first, to get away from you. Thereby, it might take them slightly longer to find the platform, and revers if you stand at SE.
Maybe you should just compromise and stand between SE and SW, if that is possible?
I haven't done MWM myself, but I have done Barnes Maze as a milder alternative. I was one clue among several large clues in the room. I sat at the end of the table where the "hiding hole" was. The mice needed to go in my direction and a little to the side to find the hole.
They definitely used the large clues in the room a lot. I tested this by switching some of the large clues (those that were movable) around and sat at the other side of the table myself. The mice responded by going directly opposite of the "hiding hole", even though they, at that point, were highly trained at finding it.
I did switch some smaller clues as well along with the large ones. But personally, I think the large clues were the most important.
Dear Yun, the experimenter should always stand in the same place, hence becoming a spatial cue. If release points for the animals are randomized across trials, there will not be problems related to choosing a position which is too close to the hidden platform and making the task too easy.
If you have to change position during the task, you can use a black curtain around a side of the Morris water maze. The experimenter can go behind the curtain after having released the animal and white shapes can be applied on the curtain as spatial cues.
Hello Dear Raffaele,
Thank your for you explanation.
I do agree with your point. So I'm not so curious about the location of experimenter now. But still, I feel the movement may affect the mice.
I move to the location after putting the mice into the pool, and stay there during the task. I don't think a curtain is reasonable, since the animal will use the distal cue in the room to find the platform.
I'm just thinking if it is reasonable that I just disappear after releasing the mouse.
We generally use a long stick with attached a small cylinder at its end to release the mice at the chosen point. Maybe this could help you.
A hand-made tool can easily be realized. You can use a small plastic becher fixed to a long stick. Good luck with the MWM!