Brown Institute for Brain Science

Spontaneous Alternation Task

Rationale of Test

This task is loosely based on foraging patterns of mice. In the task, a single arm of a T-maze is baited with a small reward (sucrose pellet or bit of cereal), the mouse is allowed to explore and find the reward. On the following task, the opposing arm of the maze is baited. The mouse engages in a strategy of alternating between arms of the T-maze, theoretically recognizing that they have already visited one of the arms and retrieved the food. This pattern is typically repeated for 10 trials. Number of days to 80% correct (first entry is the baited arm) is often used as successful performance on the task. This task indexes both spatial memory and working memory

Apparatus

T-maze, small darkened containers to hold reward, sucrose pellets, stop-watch,

Procedure

Mice are typically food deprived to 85% free feeding bodyweight. Mice are placed in a start chamber and a single arm of the maze is baited with a small reward. The trial is then started by allowing the mouse to explore the T-maze. The first arm entered is the dependent measure that is collected. The mouse is allowed to continue to explore until they find and eat the food reward. On subsequent trials, the rewarded arm is alternated. First arm choice continues to be collected for 10 trials per day. The mouse is deemed successful when they achieve 80% correct in initial choice.

Interpretation

A greater number of days to reach criterion suggest impairments in spatial or working memory when compared with a control group.

Relevant Controls

An additional spatial or working memory task to confirm any observed deficits or enhanced performance.

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