First, the experimental principle
Nearly half a century ago, Kivy and Dember et al. demonstrated that rats can discern the changes in the color of the two arms of the T-maze. They found that male rats were placed in the main arm of the T-shaped labyrinth for 15-30 minutes, allowing them to see but not into the black and white arms. Then, change the color of one of the arms so that both arms are black or white. The rats were allowed to freely select the T-arm. The results show that the rat always chooses the arm that changed the color (new arm). This process relies on the memory of the animal to complete. The resulting T-shaped maze experiment has become one of the most commonly used animal models for evaluating spatial memory. Of course, the current T-shaped maze uses the color of food rather than the arm as the driving force for animal exploration. This model is often used to study the spatial working memory of an animal, i.e., to determine information that is useful only to the animal during current operations. The improved T-shaped maze can also be used to evaluate reference memory, which is information that is useful for any day or any test in this experiment. The T-maze produced by Anhui Zhenghua Bio-Instrument Equipment Co., Ltd. is a classic behavioral method for detecting spatial working memory of rodents, and is related to the function of prefrontal cortex. The mice were dieted to 85% of their original body weight.
Technical Parameters:
1, the total time of the experiment
2, the total distance of the event
3, the number of left arm entry
4, the right arm enters the number of times
5, left arm latency (time from the main arm into the left arm)
6. Right arm latency (time from the main arm to the right arm)
7, the main arm staying time
8, the main arm activity path
1) The open field has a variety of geometric figures to facilitate the delineation of open fields of various shapes;
2) Support offline and online real-time analysis, saving experiment time and experimenters
3) The software automatically tracks and analyzes and generates EXCEL files, which can be directly analyzed by statistical analysis software such as SPSS; (the software also comes with powerful analysis functions, including more than 30 kinds of statistical tests)
4) It can manually record up to 26 kinds of phenomena that cannot be detected by video software, such as the number of standings, the number of grooming, the number of faeces, the number of hops, etc.
5) The video capture has the original video to ensure the testability; (the software can choose to save the original video, or you can choose not to save the video to save hard disk space)
6) The experimental process is automated, avoiding subjective errors introduced by manual observation and counting and interference with experimental animals;
experimental method
1 2 days before the training, stroke the mouse and put it into the T-maze for 10 min. Put the food in the labyrinth bowl and take it out after the mice have finished feeding.
2 training experiments: each trial consists of two parts, namely forced run and test run. Forced run: Select one arm of the T-maze and close it with a wooden gate. The mouse can only enter one arm to get food. After the feeding is completed, remove it immediately and wash it with alcohol to remove the odor. After 15 s, remove all gates. Test run: Both arms are open, the mouse is placed in the starting arm. If the mouse selects the arm that has not entered, the food is rewarded for correct selection; if it is repeated into the same arm, it is wrong choice, no food is given. Each animal was subjected to 4 trials per day, 15 minutes apart for 4 consecutive days, and the correct rate of each group of mice per day was calculated. When the average correct rate is above 85%, the training phase ends. T lab experiment method
3 Test experiment: extend the time interval between forced run and test run to 1 min and 3 min, and calculate the correct rate of each group of mice.
The experimental method is as follows:
(1) Fully stroke the rats for 1~2min every day for 5~7d. Since the rat is not deprived of food, the only thing that has a driving effect on the rat is its desire to explore the maze. Therefore, the animal must be fully adapted to the experimenter and the experimental environment without fear. It is especially important to fully touch the rat.
(2) Place the rat in the trunk arm of the T-shaped maze; open the gate and let the rat leave the trunk and enter a target arm (the limbs enter the arm).
(3) Put the rat back into the main arm and limit it to the arm for a period of time (zero countdown, but it is appropriate to set 5s at the beginning).
(4) The operations of the second and third steps are repeated 9 times, and the number of times of entering each arm is recorded. Control rats in each experiment
During the period (10 training sessions), the two target arms should be alternately selected. The experimental results are expressed as the number of alternating periods in the same experimental period divided by the total number of selections. This ratio decreases when methods such as medication or related brain damage are used to reduce memory.
(3) Precautions
1. Rats and mice have good spatial discrimination and can quickly learn and operate the maze accurately. Therefore, the T-shaped maze and the radial arm maze are widely used to test the spatial memory ability of animals. The T-shaped maze is used to study the effects of different brain regions on spatial memory. It is sensitive to the damage of certain brain structures, especially the hippocampus. In addition, many drugs or toxins can enhance or impair the spatial memory of animals in the T-shaped maze. In addition to rats and mice, the animals used in the experiment include pigs, sheep, turtles and pigeons.
2. The accuracy of animal selection is related to the interval between two choices and the number of selected trainings per training interval. Normal animals have a very high selection accuracy over short intervals (eg 5 s). And after a very long interval (for example, more than 1 h), its selection is close to random operation. Forced to choose training. If you only select one target arm, the accuracy is usually very high. However, if multiple selections are given, the more the number of selections, the worse the accuracy.
3. Rodents have a one-way preference. This one-way preference is related to animal species and strains. For example, C57BL/6J mice, ICR mice, and Purdue-Wistar rats prefer the left side, while Spague-Dawley rats and Wistar rats prefer the right side. Studies have shown that more than two-thirds of male Spague-Dawley rats prefer the right side, preferring less than one-fifth of the left side. This one-way preference can influence the evaluation of animal learning and memory.
4. The gate of the trunk arm is an important feature of the T-shaped maze. It can be used to limit animals to the starting box for a certain period of time between selections, and to prevent animals from exploring the maze between training sessions. Therefore, the animal should be quickly placed back into the starting box in the main arm between the two selection exercises. This is important to ensure that the animal does not explore the contralateral target arm.
5. When the animal's fear of the maze or the experimenter's stress exceeds its desire for inquiry and foraging, the animal's exploration of the maze is reduced, and even staying in the labyrinth does not move to explore the maze. This fear is manifested in the fact that the animal defecates and urinates in the maze; when it is caught, the animal screams. Therefore, adequate stress adaptation is necessary. Otherwise, if the animal does not select the arm within the maze, it is impossible to know whether its memory is normal or weak.
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