Welcome to Maze Engineers: Maze Basics. Today we’ll talk about the T maze.
A Trial Run on the T Maze
The T Maze is, as you would expect, in the shape of a T. The mouse begins its trial at the base of the T and moves to the arms of the maze, which can contain a food reward. Once the mouse turns into one of the arms, a door comes down keeping the mouse in the arm and preventing it from moving backward in the maze.
There are two main ways of using the T maze: to test spatial memory using rewarded alternation and to test spatial learning using spontaneous alternation. Let’s go over what each of these would look like.
Spatial Memory Using Rewarded Alternation
For this test, the mouse is first familiarized with the T maze before the trial begins. For the test run, rewards are placed at the ends of both arms, and one arm is then closed. The mouse is placed at the base and runs to the open arm to eat the food reward. Then, the other arm (which was previously closed off) is opened. The mouse is placed back at the base and is now able to choose between the arms for whichever one has a food reward (it can’t see which one has the reward before it turns in). If the mouse chooses the newly opened arm, hence making it rewarded alternation, it chose correctly and gets the reward. If it chooses the same arm as it chose the first time, it chose incorrectly and will not get any food reward.
Spatial Learning Using Spontaneous Alternation
To test spatial learning with the T maze, the mouse is not first familiarized. Food rewards are placed in both arms, which both start open, unlike when testing for spatial memory. The mouse starts at the base and chooses an arm to go down, and gets the food reward. When it starts at the base again, the mouse tends to choose the other arm, which shows that it has remembered that it went down the first arm already.
The difference between the two protocols lies in the availability of choices for the animal. For rewarded alternation, the animal is first habituated to the maze and then it has a predetermined course. Spontaneous alternation, on the other hand, relies on spontaneous exploration and alternation, which can be a benefit to studying the hippocampus (Deacon & Rawlins 2006).
What does the T Maze Test?
Because the T maze requires the mouse to memorize or learn which arm they previously went down, the T maze is used for testing learning and memory and all the disorders, conditions, and drugs that can affect this.
One condition that affects learning and memory is Alzheimer’s disease. In a study by Chapman et. al. (1999), they used mice which overexpressed a mutated human amyloid precursor protein, which simulated Alzheimer’s disease in their mouse model. They found that control mice increased the percent of correct choices on the T maze until their performance was better than 80% correct. Alzheimer’s mice that were only 2 months old did just as well on learning the T maze as the controls. In contrast, the Alzheimer’s mice that were 16 months old failed to improve at the T maze during training and were impaired compared to the controls. This implies that the Alzheimer’s condition with age can worsen learning and memory.
Another version of the T maze is called the multiple T maze. This is much more complicated as it includes many more T junctions and intersections. Other mazes that are similar to the T maze include the Y maze, the Barnes maze, and the Morris water maze. For more Maze Basics, be sure to check out our Maze Basics section.
References
Chapman PF, White GL, Jones MW, Cooper-Blacketer D, Marshall VJ, Irizarry MS, Younkin LH, Good MA, Bliss TVP, Hyman BT, Younkin SG, Hsiao KK (1999). Impaired synaptic plasticity and learning in aged amyloid precursor protein transgenic mice. Nature Neuroscience 2:271-276.