Search strategy analysis of Tg4-42 Alzheimer Mice in the Morris Water Maze reveals early spatial navigation deficits

Experiments

Items

Material	Material Usage	Supplier
Morris Water Maze (MWM)	To evaluate spatial reference memory in mice	N/A
Pathfinder software	For analyzing swimming strategies	Jason Snyder Lab, Vancouver, Canada
ANY-Maze video tracking software	For tracking escape latency, quadrant preference, and swimming speed	Stoelting Co., Wood Dale, USA
Opaque water	Filling the MWM pool	N/A

Instructions

1
Perform 3 days of cued training to rule out possible motor or sensory deficits. The platform should be marked with a flag and no additional distal cues should be present. Mice should be introduced near the edge of the pool, facing the wall, and allowed 1 minute to find the platform. Record escape latency.
2
Forty-eight hours after cued training, conduct acquisition training for 5 days. Remove the flag from the platform and use additional distal and proximal cues. The platform location should remain stationary while entry points change. Record escape latency.
3
Twenty-four hours after acquisition training, perform the probe trial. Remove the platform and introduce mice from a novel entry point opposite the former platform location. Allow mice to swim freely for 1 minute. Record time to reach the target, quadrant preference, and swimming speed using ANY-Maze software.
4
Analyze searching strategies during acquisition training and probe trial with Pathfinder. Categories include 'direct path,' 'directed search,' 'focal search,' 'indirect search,' 'chaining,' 'scanning,' 'random search,' and 'thigmotaxis.'
5
Quantify cognitive performance using a scoring system where higher cognitive strategies receive higher scores (0-6). Calculate the average cognitive score for each mouse per day.

Methodologies

To evaluate spatial reference memory, the Morris Water Maze (MWM) was performed. Mice were trained to search a hidden circular platform in a pool filled with opaque water. The pool was divided into four virtual quadrants. Each mouse underwent cued training, acquisition training, and a probe trial.