A non-human primate visual-spatial working memory testing cage

Abstract

This invention discloses a non-human primate visual-spatial working memory testing cage. This invention uses a non-human primate visual-spatial working memory testing cage to measure the learning, discrimination, and reversal abilities, or cognitive and memory abilities, of non-human primates, providing a more comprehensive evaluation of changes in animal brain function and behavior. It can provide a model evaluation tool for central nervous system diseases such as Alzheimer's disease and stroke, and offer new methods for disease research and new drug development.

Description

Technical Field

[0001] This invention belongs to the field of neurobiology, specifically relating to a non-human primate visual-spatial working memory testing cage, which can test the learning and reversal abilities, or cognitive and memory abilities of non-human primates. Background Technology

[0002] Due to their close kinship with humans, non-human primates play an indispensable role in studying the mechanisms of human diseases and developing novel drugs. In neurobiology, behavioral tests on laboratory animals are frequently required. By having these animals complete specific behavioral patterns, their cognitive abilities, learning abilities, and brain functions are assessed, thereby revealing the patterns of brain activity and providing evaluation methods for neurological disease models (Alzheimer's disease models, Parkinson's disease models, etc.). Laboratories need to measure the cognitive, memory, learning, and reversal abilities of non-human primates as an important means of evaluating disease models and drug efficacy.

[0003] Existing non-human primate behavior testing cages include the traditional WGTA cage and the more recently developed touchscreen multifunctional cognitive function testing cage. The traditional WGTA cage is relatively small, which is detrimental to animal welfare and operator convenience. It also has drawbacks in areas such as barrier operation, animal waste disposal, animal entry and exit, operator privacy, and scientific rigor. The touchscreen multifunctional cognitive function testing cage is mainly used for cognitive function testing of non-human primates. Different patterns randomly appear on the screen, and monkeys are rewarded for correctly identifying the pattern. However, this cage has a limited scope of application and is not suitable for testing memory, learning, or reversal abilities.

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a non-human primate visual-spatial working memory testing cage, which can be used to test the learning and reversal abilities, or cognitive and memory abilities of non-human primates. Utility Model Content

[0005] The purpose of this invention is to provide a non-human primate visual-spatial working memory testing cage that can measure the learning and reversal abilities, or cognitive and memory abilities, of non-human primates, and more comprehensively evaluate changes in animal brain function and behavior. It can provide a model evaluation method for central nervous system diseases such as Alzheimer's disease and stroke, and provide new methods for disease research and new drug research.

[0006] The present invention relates to a non-human primate visual-spatial working memory testing cage, characterized in that the training cage comprises a first cage body and a second cage body connected together, a support frame is provided between the first cage body and the second cage body, slides are provided on the edges of the support frame on both sides, an opaque plate is provided between the first cage body and the second cage body, the two sides of the opaque plate are inserted into the slides, so that the opaque plate separates the first cage body and the second cage body, the second cage body is provided with an observation cage, a training tray placement layer, a food placement layer and a leg placement space from top to bottom, the front wall of the observation cage is provided with a one-sided visible glass, a camera for observing the situation inside the observation cage is provided below it, a tray for placing feces and urine is provided below the first cage body, a hole is provided on the upper edge of the support frame, a hook is provided on the right edge of the support frame, a rope is fixed on the upper side of the opaque plate, the rope passes through the hole on the upper edge of the support frame, and a weight is hung at the end of the rope, the weight can be locked on the hook, and several universal wheels with locking buckles are provided below the training cage;

[0007] The first cage is for holding the animals, and the second cage is for holding the training tray and camera.

[0008] The training tray is shaped like a spoon, with a concave center.

[0009] Preferably, the bottom of the first cage has a feces and urine tray that can be pulled out for cleaning and is locked to the cage with a buckle to prevent monkeys from reaching under the cage to move the feces and urine tray.

[0010] Preferably, the cage for placing animals has a latch 4 at the top of the door. Correspondingly, there is a hole at the top of the door for animal entry and exit. After the monkey enters the cage, it can lower the door and push out the latch to lock the door effectively. There is a recess on each of the two edges of the lower middle part of the door. When the door is lifted, there is also a latch at the corresponding position of the recess at the top of the cage. Pushing out the latch can effectively fix the door and prevent it from falling.

[0011] Preferably, the opaque board between the first and second cages is raised and lowered using a combination of two pulleys, a rope, and a weight. A downward-facing hook on the side of the cage allows the rope to be hooked, thus fixing the board at the desired height. The two pulleys reduce the weight pressure of the opaque board on the technician, allowing the technician to easily and quickly raise the board, achieving precise control over the board-raising time during training and reducing errors.

[0012] Preferably, both the bottom of the first cage and the second cage are equipped with lockable casters.

[0013] Preferably, the training tray is made of stainless steel.

[0014] Preferably, the training tray also has a lid, which is an opaque acrylic sheet or cup, or other material such as plastic, stainless steel, etc.

[0015] Preferably, the cover of the training tray is made of stainless steel, is round, and has two screws at one end for connection to the training tray.

[0016] Advantages:

[0017] This invention uses an optimized testing device to measure the learning, discrimination, and reversal abilities, or cognitive and memory abilities, of non-human primates, providing a more comprehensive evaluation of changes in animal brain function and behavior. It can provide model evaluation methods for central nervous system diseases such as Alzheimer's disease and stroke, and offer new methods for disease research and new drug research.

[0018] The training tray (food well) used in this invention employs a mortise and tenon structure, allowing it to be used individually or in combination in pairs or multiples. No screws are required for assembly, ensuring a secure fit while also facilitating disassembly. It can be used for delayed response two-hole training, multi-hole training, and also for the learning discrimination and reversal training paradigm of this invention.

[0019] The training tray (food well) used in this invention is made of stainless steel and is quite heavy, so that monkeys cannot easily pick it up, thus preventing monkeys from mischievously moving or overturning the food tray.

[0020] The training trays (food wells) should be of uniform size and depth to avoid the food wells being too deep and difficult to reach, thus affecting the monkeys' appetite, or too shallow, so that the food is not completely covered when the lid is on. Furthermore, uniform food well size, combined with uniformly sized food (such as apple chunks), improves the reproducibility of the experiment.

[0021] The training disc uses a mortise and tenon structure, with a protruding semi-cylindrical shape on one side and a semi-cylindrical recess on the other side. It can be used alone or assembled in pairs or multiples. No screws are required for assembly, making it sturdy and easy to disassemble.

[0022] The lid on the food well can be an opaque acrylic sheet, a cup, or other materials such as plastic or stainless steel. Different colors or shapes can be used to represent the objects the monkeys need to identify. This can be used for paradigm training such as delayed response, discrimination learning, and reversal.

[0023] If necessary, the food well cover is made of stainless steel, round, with two screws at one end to connect to the food well. When monkeys open the cover to get food, this prevents them from mischievously taking the cover to play with.

[0024] Advantage 1 of the training cage: Compared to other training cages, the training cage used in this invention consists of two cages. The first cage is for holding the animal, and the second cage is for holding the training tray and camera. The second cage is made of opaque acrylic sheet and can be tightly connected to the first cage with a locking mechanism. This effectively prevents the animal from being affected by external factors, allowing it to see only the training tray during training and thus focus better. The two cages can also be disassembled and used separately for other experimental needs.

[0025] Advantage 2 of the training cage: During training, the person sits on the outside of the second cage, with a one-way mirror installed in front. The staff can observe the training tray and the animal through this mirror, and perform actions such as placing food or setting up the tray. The animal cannot see the staff, preventing distractions and allowing for greater focus during training. It also effectively prevents staff from giving the animal prompts or artificially interfering with the training outcome in an attempt to improve accuracy or reduce working hours.

[0026] Both discrimination training and reversal training use two training trays. This invention requires that the distance between the two training trays be consistent with that between the animal and the food tray to prevent the animal from choosing the food tray that is closer to it, thereby reducing factors that may affect the training results.

[0027] Advantage 3 of the training cage: A platform for mounting a camera is located below the mirror. From this angle, the training process and the training tray can be captured from the center front. If the camera is installed in a corner, distant objects will appear smaller and closer objects larger, making it seem as if the distance between the training tray and the animal is inconsistent when viewed by others. Shooting from the center front accurately reproduces the training scene.

[0028] Advantage 4 of the training cage: The second cage has three layers, each with a different height. The bottom layer is more spacious, allowing the trainer to comfortably place their feet and preventing fatigue during long training sessions. The middle layer is the narrowest and is used to store training food (peanuts, apple pieces, etc.), with its height matching the trainer's hand height when seated, preventing hand fatigue during training. The top layer is the training space. The bottom layer is slightly wider than the top two layers, with a protruding section in the food storage area for easy access to food.

[0029] Advantage 5 of the training cage: First, there is a urine / feces tray at the bottom of the cage, which can be pulled out for cleaning and is locked to the cage body with a latch to prevent monkeys from reaching under the cage to move the urine / feces tray. The height of the urine / feces tray is such that it is tightly connected to the cage with virtually no gaps, preventing urine from splashing everywhere outside the cage when the monkey urinates.

[0030] Advantage 6 of the training cage: The cage for placing animals has a latch at the top of the door. Correspondingly, the animal entrance / exit door has a hole at the top. After the monkey enters the cage, the door is lowered, and the latch is pushed out to lock the door effectively. There is a recess on each of the two edges of the lower middle part of the door. When the door is lifted, there is a corresponding latch at the top of the cage at the recessed position. Pushing out the latch will effectively lock the door and prevent it from falling. Technicians do not need to lift the door while herding the monkey from the transfer cage into the training cage, effectively freeing up the technicians' hands and making the work more convenient.

[0031] Advantage 7 of the training cage: The opaque panel between the animal cage and the training cage is raised and lowered using a combination of two pulleys, a rope, and a weight. A downward hook on the side of the cage allows the rope to be hooked, thus fixing the panel at the desired height. The two pulleys reduce the weight pressure on the technician from the opaque panel, allowing the technician to easily and quickly raise the panel, achieving precise control over the timing of the pull and reducing errors.

[0032] Advantage 8 of the training cage: Both the training cage and the animal cage have lockable casters at the bottom, which makes them easy to move and easy to fix in place during use, preventing the monkey from shaking the cage and affecting training. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the training cage structure; Detailed Implementation

[0034] The following embodiments are further illustrations of the present invention, but not limitations thereof.

[0035] like Figure 1 As shown, the training cage of this utility model includes a first cage body 5 and a second cage body 15 connected (e.g., connected by a latch 8). A support frame 3 is provided between the first and second cage bodies, and slide rails are provided on the edges of the support frame on both sides. An opaque plate 2 is provided between the first and second cage bodies, with both sides of the opaque plate engaging the slide rails, thus separating the first and second cage bodies. The second cage body is provided with an observation cage 1, a training tray placement layer 12, a food placement layer 11, and a leg placement space 10 from top to bottom. The front wall of the observation cage is provided with a one-way visible glass 14, and a camera 13 for observing the situation inside the observation cage is provided below it. A tray 7 for placing feces and urine is provided below the first cage body. A hole is provided on the upper edge of the support frame, and a hook 16 is provided on the right edge of the support frame. A rope 17 is fixed on the upper side of the opaque plate, passing through the hole on the upper edge of the support frame, and a weight 6 is hung at the end, which can be secured to the hook 16. Several universal wheels 9 with latches are provided below the training cage.

[0036] The training cage used in this invention consists of two cages. The first cage is for holding the animal, and the second cage is for holding the training tray and camera. The second cage is made of opaque acrylic sheet and can be tightly connected to the first cage with a locking mechanism. This effectively prevents the animal from being affected by external factors, allowing it to see only the training tray during training and thus focus better. The two cages can also be disassembled and used separately for other experimental needs.

[0037] During training, the person sits on the outside of the second cage, which has a one-way viewing glass in front. Through this glass, the staff observes the training tray and the animal, and performs actions such as placing food or setting up a playpen. The animal cannot see the staff, preventing distractions and allowing for greater focus during training. This also effectively prevents staff from giving the animal prompts or artificially interfering with the training process in an attempt to improve accuracy or reduce work time.

[0038] Both discrimination training and reversal training use two training trays. This invention requires that the distance between the two training trays be consistent with that between the animal and the food tray to prevent the animal from choosing the food tray that is closer to it, thereby reducing factors that may affect the training results.

[0039] A platform for mounting cameras is located below the glass. From this angle, the training process and the training tray can be captured from the center front. If the camera is installed in a corner, the video will show distant objects appearing smaller and closer objects appearing larger, making it seem to others viewing the video that the distance between the training tray and the animal is inconsistent. Shooting from the center front accurately reproduces the training scene.

[0040] The second cage has three layers, each with a different height. The bottom layer is more spacious, allowing trainers to comfortably place their feet and preventing fatigue during long training sessions. The middle layer is the narrowest and is used to store training food (peanuts, apple pieces, etc.). Its height is the same as the trainer's hand height when seated, preventing hand fatigue during training. The top layer is the training space. The bottom layer is slightly wider than the top two layers, and has a protruding section in the food storage area for easy access to food by the trainer.

[0041] The first cage has a urine / feces tray at the bottom, which can be pulled out for cleaning. It is secured to the cage with a latch to prevent monkeys from reaching under the cage to move the tray. The tray is fitted tightly to the cage with virtually no gaps to prevent urine from splashing outside the cage when the monkey urinates.

[0042] The cage for placing animals has a latch 4 at the top of the door. Correspondingly, there is a hole at the top of the animal entrance / exit door. After the monkey enters the cage, the door is lowered, and latch 4 is pushed out to lock the door effectively. There is a recess on each of the two edges of the lower middle part of the door. When the door is lifted, there is a latch at the corresponding position on the top of the cage. Pushing out the latch will effectively lock the door and prevent it from falling. Technicians do not need to lift the door while herding the monkey from the transfer cage to the training cage, effectively freeing up the technicians' hands and making the work more convenient.

[0043] An opaque board between the animal cage (first cage) and the training cage (second cage) is raised and lowered using a combination of two pulleys, a rope, and a weight. A downward-facing hook on the side of the cage allows the rope to be hooked, thus fixing the board at the desired height. The two pulleys reduce the weight pressure on the technician from the opaque board, allowing the technician to easily and quickly raise the board, achieving precise control over the timing of the pull during training and reducing errors.

[0044] Both the training cage and the animal cage have lockable casters at the bottom, making them easy to move and secure during use, preventing the monkeys from shaking the cages and affecting training.

[0045] The training tray (food well) used in this invention is made of stainless steel and is quite heavy, so that monkeys cannot easily pick it up, thus preventing monkeys from mischievously moving or overturning the food tray.

[0046] The training trays (food wells) are shaped like spoons, concave in the middle, and of uniform size and depth. This avoids the food wells being too deep and difficult to reach, which could affect the monkeys' appetite, or too shallow, which would not completely conceal the food when covered. Furthermore, the uniform size of the food wells, combined with the uniform size of the food (such as apple chunks), improves the reproducibility of the experiment.

[0047] The lid on the food well can be an opaque acrylic sheet, a cup, or other materials such as plastic or stainless steel. Different colors or shapes can be used to represent the objects the monkeys need to identify. This can be used for paradigm training such as delayed response, discrimination learning, and reversal.

[0048] If necessary, the food well cover is made of stainless steel, round, with two screws at one end to connect to the food well. When monkeys open the cover to get food, this prevents them from mischievously taking the cover to play with.

[0049] Example 1: Testing the delayed response memory ability of experimental monkeys using this test cage.

[0050] I. Preparations before the experiment

[0051] The experimental animals are non-human primates. Before the experiment begins, the animals should be placed in individual experimental cages and fed by designated keepers or technicians until the experimenters do not have an excessive reaction when they enter the animal room.

[0052] II. Adaptation Phase

[0053] 1. Adaptation and domestication: The animal is interacted with by a keeper or laboratory technician. Free feeding is stopped, and the animal's green fodder and rice cake are cut into 1*1*1 small cubes, handed to the animal, and allowed to try to take the food cubes from the keeper's hand.

[0054] 2. Independent feeding: After the animal establishes contact with the technicians, it can be transferred to a test cage, where food is placed on a feeding board for the monkey to feed itself.

[0055] 3. Lid-opening training: After completing the independent feeding training, the monkey can be transferred to the test cage, food can be placed in the feeding hole of the food board, the lid can be closed, and the monkey can be induced to open the lid. The training is complete when the monkey can open the lid independently without being induced.

[0056] 4. Delay board training: After completing the lid-opening training, before the monkey takes food during the lid-opening training, lower the delay board and immediately pull it up. Then, induce the monkey to open the lid and take food. Continue this process until the monkey can take food on its own without being induced.

[0057] III. Delayed Response Training

[0058] 1. Transfer the monkey to the test cage, place the training food and training form, pull up the delay board, open the feeding hole cover, and turn on the camera after the monkey calms down to begin delayed response training.

[0059] 2. Place the food into the feeding hole according to the training table, lower the delay board, and pull the delay board back up after the delay time shown in the table. Let the monkey eat freely and record whether it eats correctly. If the wrong lid is opened, the reward food is canceled.

[0060] 3. Repeat step 2 for a total of 30 training sessions.

[0061] 4. Record the results and save the video data.

[0062] IV. Delayed Response Training Form

[0063] The training table is shown in the figure below: where L / R represents the reward food being placed on the left or right feeding hole; A, B, C, D, and E represent delays of 0-4 times the B value (seconds): for example, if the B value is 5, then C represents a delay of 10 seconds.

[0064]

[0065] V. Training Result Cases

[0066] 1. Animals: 8 crab-eating macaques, aged 8-12 years.

[0067] 2. Experimental objective:

[0068] A monkey model of Alzheimer's disease (AD) was created, and the delayed response training paradigm was used as one of the model evaluation metrics.

[0069] 3. Experimental procedure: see above.

[0070] 4. Experimental Results:

[0071]

[0072] As can be seen from the table above, after the administration of the drug to monkey No. 1, the B value and the maximum memory time decreased, indicating a decline in short-term memory ability.

[0073] Example 2: Testing the learning reversal ability of experimental monkeys using this test cage.

[0074] I. Preparations before the experiment:

[0075] 1. The monkeys need to be cared for by a designated keeper, and the monkeys do not react excessively when the keeper enters the monkey enclosure.

[0076] 2. During the feeding process, the zookeeper places food in his hand and guides the monkey to reach out and take the food, thus establishing a trust relationship.

[0077] 3. Find 2-3 favorite foods for each monkey during feeding to use as rewards for later training.

[0078] II. Delayed Response Training

[0079] 1. Perform delayed response training according to Example 1.

[0080] III. Learning Reversal Adaptation Training

[0081] 4. Place the monkey in the first cage, turn on the camera, and begin the experiment after the monkey has calmed down.

[0082] 5. Place a food well in the middle of the control panel in front of the monkey.

[0083] 6. Lower the opaque barrier, place the reward food in the food well, and cover it with the A-colored lid. Pull up the barrier and wait for the monkey to take the food before lowering it again. Repeat the above steps 30 times. If the monkey correctly obtains the reward food 27 times in 30 training sessions (i.e., an accuracy rate of over 90%), it can proceed to the next training step the following day; otherwise, repeat this training.

[0084] IV. Color Discrimination Training

[0085] 1. Place the monkey in the first cage, turn on the camera, and begin the experiment after the monkey has calmed down.

[0086] 2. Assemble the two food wells together.

[0087] 3. Lower the barrier, place the food in the food wells according to the table, cover with the B-colored lid, cover the opposite well with the C-colored lid, pull up the barrier, and wait for the monkey to eat (if the wrong food well is selected, the reward will be canceled) or if the monkey does not eat after 60 seconds, the reward will be canceled, and the barrier will be lowered. Repeat this step 30 times.

[0088] 4. If the monkey correctly receives the reward food 27 times in 30 training sessions, that is, the accuracy rate is above 90%, then reverse training will be carried out on the afternoon of the same day or the morning of the next day (within 12 hours). Otherwise, this training will be repeated.

[0089] V. Reversal Training

[0090] 1. Place the monkey in the first cage, turn on the camera, and begin the experiment after the monkey has calmed down.

[0091] 2. Lower the barrier, place the food in the food wells according to the table, cover with the C-colored lid, cover the opposite well with the B-colored lid, pull up the barrier, and wait for the monkey to eat (if the wrong food well is selected, the reward will be canceled) or if the monkey does not eat after 60 seconds, the reward will be canceled, and the barrier will be lowered. Repeat this step 30 times.

[0092] 3. If the monkey fails to receive a reward food in three consecutive training sessions, it can be fed a reward food with tweezers, and then the training can continue.

[0093] 4. If the monkey correctly receives the reward food 27 times out of 30 training sessions, that is, with an accuracy rate of over 90%, the training is considered successfully reversed and training is stopped. Otherwise, repeat the training.

[0094] VI. Data Processing

[0095] After training is completed, data such as the number of training sessions and training days required for color discrimination training and reversal training are collected to preliminarily assess the monkeys' learning ability. Further training is conducted within a specified timeframe after successful model establishment, and post-operative indicators are collected (since this training is a learning behavior, no further adaptive training is needed). The control group and the model group are compared, and significant differences are observed before and after model establishment to analyze the impact of model establishment on monkey behavior.

[0096] VII. Record Form

[0097]

[0098] VIII. Training Result Cases

[0099] 1. Animals: 8 crab-eating macaques, aged 8-12 years.

[0100] 2. Experimental objective:

[0101] A monkey model of Alzheimer's disease (AD) was created, and the learning reversal training paradigm was used as one of the model evaluation indicators.

[0102] 3. Experimental procedure: see above.

[0103] 4. Experimental Results:

[0104]

[0105] Note: Original Learning - Color Recognition Training; Reversal Learning - Reverse Training

[0106]

[0107]

[0108] As can be seen from the table above, the number of training sessions required for monkey No. 1 to reach a certain standard in color recognition and reversal training after drug administration and modeling increases, indicating that its learning ability and reversal ability are declining.

Claims

1. A non-human primate visual-spatial working memory testing cage, characterized in that, The non-human primate visual-spatial working memory testing cage includes a first cage and a second cage connected together. A support frame is provided between the first and second cages, and slides are provided on the edges of the support frame on both sides. An opaque plate is provided between the first and second cages, and the two sides of the opaque plate are inserted into the slides, so that the opaque plate separates the first and second cages. The second cage is provided with an observation cage, a training tray layer, a food layer and a leg space from top to bottom. The front wall of the observation cage is provided with a one-way visible glass, and a camera is provided below it to observe the situation inside the observation cage. A tray for placing feces and urine is provided below the first cage. A hole is provided on the upper edge of the support frame, and a hook is provided on the right edge of the support frame. A rope is fixed on the upper side of the opaque plate, and the rope passes through the hole on the upper edge of the support frame, with a weight hanging at the end. The weight can be locked on the hook. Several universal wheels with locks are provided below the non-human primate visual-spatial working memory testing cage. The first cage is for holding the animals, and the second cage is for holding the training tray and camera. The training tray is shaped like a spoon, with a concave center.

2. The non-human primate visual-spatial working memory testing cage according to claim 1, characterized in that, The first cage has a feces and urine tray at the bottom that can be pulled out for cleaning. It is secured to the cage with a latch to prevent monkeys from reaching under the cage to move the tray.

3. The non-human primate visual-spatial working memory testing cage according to claim 1, characterized in that, The cage for placing animals has a latch at the top of the door. Correspondingly, there is a hole at the top of the door for the animal's entrance and exit. After the monkey enters the cage, it can lower the door and push out the latch to lock the door effectively. There is a recess on each of the two edges of the lower middle part of the door. When the door is lifted, there is also a latch at the corresponding position of the recess at the top of the cage. Pushing out the latch will effectively lock the door and prevent it from falling.

4. The non-human primate visual-spatial working memory testing cage according to claim 1, characterized in that, The opaque board between the first and second cages is raised and lowered using a combination of two pulleys, a rope, and a weight. A downward-facing hook on the side of the cage allows the rope to be hooked, thus fixing the board at the desired height. The two pulleys reduce the weight pressure of the opaque board on the technician, allowing the technician to easily and quickly raise the board, achieving precise control over the board-raising time during training and reducing errors.

5. The non-human primate visual-spatial working memory testing cage according to claim 1, characterized in that, Both the first and second cages use lockable casters at their bottom ends.

6. The non-human primate visual-spatial working memory testing cage according to claim 1, characterized in that, The training tray is made of stainless steel.

7. The non-human primate visual-spatial working memory testing cage according to claim 1, characterized in that, The training tray also has a lid, which is an opaque acrylic sheet or cup.

8. The non-human primate visual-spatial working memory testing cage according to claim 1, characterized in that, The cover of the training tray is made of stainless steel, is round, and has two screws at one end for connecting to the training tray.

9. The non-human primate visual-spatial working memory testing cage according to claim 1, characterized in that, The training disc uses a mortise and tenon structure, with a protruding semi-cylindrical shape on one side and a semi-cylindrical recess on the other side.

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