【Purpose】

1. Learn the principles of the Y-maze experiment.

2. Master the Y-maze experimental method.

3. Observe the learning and memory ability of experimental animals in the process of establishing conditioned reflex.

[Experimental principle]

Through light and electrical stimulation, the animals are formed to avoid conditioned reflexes, and the animal's avoidance condition response ability and spatial discrimination ability are observed and recorded. Analyze and infer the ability of animals to learn, remember, and spatially recognize.

[Laboratory Animals]

Rat, mouse. (More experimental information reference: )

【experiment equipment】

The Y-maze consists of a three-part radiant lost box and controller, and is provided by Shanghai Xinsoft Information Technology Co., Ltd. The three-part radiant lost box consists of the I, II, III arms of the same length and the junction of the three. An electric grid with a diameter of 0.2 cm, a length of 14 cm and a spacing of 1 cm is laid on the bottom of the box. Each arm is 45cm long and each has a 15W stimulation signal on the top. The Y-maze control unit has voltage control button, delay control button, automatic control button and four buttons I, II, III and 0. When the I, II, III buttons are pressed respectively, the corresponding arm signal light is on. When the arm is not energized as a safe zone (red light zone), the two arms and the junction zone without lights are energized to become a non-safe zone (shock zone). When the 0 button is pressed, the three arms are not energized, but the junction area is energized. After the signal light is on, the grid will only start to power up after a short pause. This short interval is adjusted by the delay control button. You can also press the automatic control button to have the lights and power on automatically controlled by the controller.

[Experimental methods and steps]

1. Sieve (pre-selection)

( 1) After the rats were placed in the Y-maze box for 3 to 5 minutes, an appropriate electric shock was applied until the three arms were explored. Active selection, sensitive to shock response, and quick response to test. Rats that were too slow or particularly sensitive to the reaction were eliminated.

( 2) Pre-selected animals that have received two consecutive correct responses when the number of electric shocks is ≤3 times, that is, rats that are more sensitive to shock response for experimental use.

( 3) On the basis of the above preliminary screening, through the formal maze training, the rats that did not meet the standard of the society (cannot learn) were eliminated.

2. True or false judgment

After being shocked, the rat flees directly from the starting area to the safe area or runs to the safe area within 10 seconds after power-on. It is “correct response”. If it escapes to any other arm without light, it is recorded as an error reaction.

3. Standard (learning) standard

( 1) 9 or more consecutive responses in 10 consecutive times (correct response rate ≥ 90%) are set as the standard of learning.

(2) 20 training tests were conducted on each experimental day, and the number of error responses (errors number EN) ≤ ​​2 times. The total reaction time (RTT) ≤ 120 s was used as a criterion for determining rat learning. Because EN reflects the correct degree of rat response, TRT reflects the length of the reaction time in rats, and can comprehensively evaluate the learning and memory ability of rats, so this standard is more reasonable.

The above is the standard for each rat (study), and the standard of the whole group of rats (study) is the correct rate of the whole group (the number of animals learned / the total number of animals in the group × 100%) is more than 85%.

4. Learning test

In the experiment, the rats were placed in the maze for 3 to 5 minutes, and then the formal experiment was started.

( 1) Random rest method: The safety zone is changed in an irregular order to train the rats to recognize the light stimulation and safety orientation. After the rat escapes to the safety zone after being shocked, the light continues to act for 10 to 15 seconds, and the light is extinguished once. Test, the arm of the rat is used as the starting point of the next test. The test interval is 30s or the rest is 1min, then the second test is repeated, and the test is repeated until the continuous 9/10 standard.

( 2) Random no-break method: When the safety zone begins to change in an irregular order, the arm of the rats is energized with the other arm, and the animal is allowed to escape for 10 hours or 30 seconds after the electric shock to escape to the light zone. The animal's arm is then tested for the next test at the beginning of the next test.

( 3) Sequential method: The end of the three arms is taken as the starting area or the safety zone by I→II→III→I arm rotation.

The above methods can also be divided into two categories: 1 fixed training times per day, generally 20 times, continuous training 3 to 4 days. Rats generally meet the learning standards. 2 Unfixed training times, using the segmented continuous training method, that is, 10 times per training, 1 minute rest, continuous training until learning, and training is completed within 1 day. The first method is generally used.

5. Memory retention (reproduction) test

After learning test for 24h, 48h, 1 week, 30d, and then test to the 9/10 standard by the same method, the correct number of reactions is set to A, and the retention ability of memory is expressed by A/10. The higher the value, the better the memory.

[observation index]

( 1) The number of training required to reach the standard (number of electric shocks, number of reactions, number of tests): The number of tests required before the animal learns to reach the standard, indicating the learning and memory scores of the spatial resolution reaction.

( 2) Number of days (days) required to meet the standard: Record the number of days each rat has reached the standard of learning.

( 3) Error number (errors number EN): The number of false reactions in all reactions completed on one experimental day.

( 4) Total reaction time (RTT): The reaction time (latency period) of the animal refers to the time taken from the start of the signal light to the first escape of the rat to the bright area of ​​the lamp. The total response time of the whole day is one. The time required to complete all reactions (including correct and incorrect reactions) on the experimental day (all day).

( 5) Active avoidance rate: The percentage of total response times when the rats completed the escape response within 5 seconds after the light was on but not energized. When the safety zone light is on and the electrical stimulation has not yet started, the rat flees to the safe zone to indicate that the rat has formed a light-dark discrimination conditional reflex (active avoidance response).

( 6) Correct response rate (behavior of behavior): The percentage of correct responses to the total number of tests.

( 7) Group correct rate: learn the number of animals as a percentage of the total number of animals in the group.

( 8) 3d learning rate: The number of animals trained to meet the learning standard on the 3rd day as a percentage of the total number of animals in the group.

【Precautions】

1. Animals are screened strictly and animals that are poorly tolerant to electric shock or insensitive to electric shock are eliminated.

2. Operational specifications, try to be operated by special personnel to reduce errors.

3. The experimental environment is quiet and the light is suitable. Try to experiment at the same time every day.

4. The stimulating voltage intensity is generally 30-70V, and the delay is 3~5s. The electrical conductivity of the grid should be stable, and the animal feces can be cleaned at any time to prevent short circuit of the grid.

【Evaluation】

Simple and easy to observe, there are many indicators. However, the animal's response is quite different, and attention should be paid to the screening of experimental animals. Animal feces tend to short-circuit the grid, and if not found in time, it will cause experimental errors.

(More experimental information reference: and Xinsoft Enterprise Blog: blog.sina.com.cn/softmaze)

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