【Animal Modeling】-The influence of dorsolateral prefrontal cortex injury on the exercise habit and performance of macaque hand grip control

  Introduction: In the past few decades, extensive research has been conducted on the dorsolateral prefrontal region (dlPFC) to reveal its role in integrating multiple cognitive attributes in working memory and its importance in risk-related decision-making . Some studies on non-human primates have also emphasized the role of dlPFC in the psychological representation of spatiotemporal motion sequences. In other words, the subject needs to reproduce a series of actions after a certain period of time. Although related to human motor control, the role of dlPFC and the basal nucleus (cerebral neural circuits) in controlling and predicting grip force contributes to hand agility, sensorimotor cortex (M1/S1) and movement. There is evidence to supplement the activities expected in the anterior cortex, auxiliary motor area, belt circumflex area, posterior and inferior parietal cortex, and brain related to primary grasping. As pointed out by Ehrsson et al. DLPFC activities related to accurate grip may also reflect parallel behavioral factors, such as spatial attention, short-term memory of tactile information, choice of exercise response, and centralized automatic monitoring of exercise performance. However, although the role of dlPFC in motor learning has been established, as motor tasks become more and more "automatic", dlPFC activation seems to gradually disappear, resulting in a "lower" brain structure. It may reflect the delegation of responsibility. Recently, Kaeser and his colleagues reported raw data on the role of dlPFC in characterizing exercise habits. In this study, the authors performed dlPFC cortical biopsies on two macaques to evaluate their effects on a range of exercise behaviors (habits). Compared with control monkeys, animals with impaired dlPFC (zone 46) have a greater impact on the spatio-temporal sequence, but the exercise ability itself (score) is not affected. In addition, the first sign is that small biopsy has less effect on exercise sequence than large biopsy, so there is a relationship between the size of dlPFC biopsy and the degree of change in exercise habits. However, due to the limited number of cases (n = 2), more data may be needed to support this hypothesis, including the number of cases and the variability of the exact location of the dlPFC lesion. It is clear. In addition, functional magnetic resonance imaging (fmri) studies on human subjects have highlighted the role of dlPFC in performing exercise tasks that require controlled (predicted) grip. This study aims to test a new treatment strategy based on a non-human primate model of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) Parkinson's disease. Transplantation of Nerve Cell Ecosystem (ANCE). In this case, unilateral biopsy of dlPFC was performed on four adult female mackerel (a few months before MPTP treatment) to provide the cellular material needed to obtain ANCE. Previously trained monkeys to perform quantitative movement (hand agility) tasks, such as the "modified Brinkman committee" task and the "hands grabbing drawer" task. Therefore, the purpose of current research on non-human primates is to expand preliminary data on the role of the prefrontal lobe (PFC) in exercise habits, mainly when dlPFC is known in advance. This is to test that it helps predictability. The grip hypothesis required for this level was recently reported in humans.

  Data are collected from 4 adult female monkeys (Mk-MY, Mk-LY, Mk-MI, Mk-LL), weighing 3.0.-5.0 kg, and their age at the beginning of behavioral training. At the age of 4-8, the recovery time is longer than that of 3 years ago. In other words, monkeys are highly trained to complete two motor tasks. The rooms are fully equipped with outdoor space and free drinking water. Each monkey will perform one or two different behavioral tasks with the experimenter every day. Before being transferred to the behavioral laboratory, each animal was voluntarily placed on the monkey’s chair and weighed. In addition, during the entire experiment, appetite, social behavior, and fur conditions were treated every day. After the behavioral test, the monkeys will eat cereals, vegetables and fruits every day.

  Motion task: Manual flexibility assessment was originally based on the "Modified Brinkman Board" task, in which particles recovered from 25 horizontal and 25 vertical holes were randomly distributed on the Plexiglas plate. Each hole contains one. Banana flavor food particles. Due to the size and shape of the hole, the monkey needs to use an accurate grip (the relative position of the thumb and index finger) to successfully obtain food pellets. One hand performs a separate task three days a week. The number of food particles recovered correctly in the first 30 seconds corresponds to a score reflecting athletic performance. Evaluate the performance of MK-LL in various ways. In fact, mk-LL is a mixture of these two effects. You can grab the pellets one by one in the desired way, or you can put all the pellets in your mouth. Previously, as explained by Kaeser et al., several pills were taken out in sequence and stored in your palm. Due to this random change, the dynamic performance of MK-LL can be calculated by calculating the total number of correctly extracted single particles and the total number of correctly extracted multiple particles in the entire task. This corresponds to the "total score". In addition, the exercise strategy (habit) is evaluated according to the time selection sequence (visiting 50 holes in sequence). The exercise strategy obtained from the sequential interviews is still a qualitative assessment of exercise habits. The same statistical methods as before are used to quantify exercise habits data. According to the position of each hole on the horizontal left and right axis of the "modified Brinkman plate", a spatial position number is assigned to it. It summarizes the absolute value of the difference of 50, and provides an index of the system's movement sequence. For example, if the monkey gradually moves along the horizontal axis from the hole on the left edge of the board to the right edge, the exercise habit index will become smaller because the difference between the spatial position (left = decimal) and the time series is small. I will. .. On the contrary, systematic scanning of the plate from right to left will produce a great indication of exercise habits, and there will be a big difference between the number of spatial positions of each hole and the number of sequences. This index can be used to evaluate whether monkeys repeat the same sequence in daily training. For example, the change of the index reflects the change of the selection order from one activity to the next, and the slight fluctuation reflects the stable selection order in consecutive sessions. Please note that mk-LL will not perform the "Modified Brinkman Board" task in accordance with the standard single particle grab procedure, and therefore cannot evaluate the motion strategy. The second task is to "extend and grab the drawer". It is used to quantify and control the grip and load (pull) force generation and the passage of time. By designing this task, the monkey opened the drawer with one hand and resisted various resistances. The task of "extending and grabbing the drawer" requires firmly grasping the drawer handle (grip strength) between the thumb and index finger and monitoring the tension (load). A standard task involves running 10 correct consecutive tests on each different resistor with each hand. The correct test is defined as successfully opening the drawer and using the handle to completely extract the particles. Each task starts with the lowest resistance (R0). After 10 correct R0 attempts, the monkey gets an extra reward (almond slice), and then the resistance increases to R3, 3 after 10 correct trials are performed, he will again get an extra reward, and his resistance to R5 Strength will increase. When one hand completes the three resistances, the other hand follows the same pattern. The report analyzes two different parameters. The first is the maximum grip produced by each test. The second is the maximum load, which is also measured in each test. Remove the first attempt of each resistance from the main analysis to represent an outlier (resistance unknown at the start of the new series of trials). In another analysis, the force generated by each resistance in the first test is compared with the force with the same resistance in subsequent tests. Four monkeys perform this task 2-3 times a week. One of the monkeys (MK-MI) successfully completed the withdrawal task with only his left hand (due to an injury to his right hand). In fact, MK-MI will not hold the drawer handle with the right hand through precise grip movement, but is another way to prevent grip strength measurement (press the top of the handle with one finger). use. Surgery: Before surgery, each animal was lightly sedated with ketamine (10 mg/kg), midazolam (0.1 mg/kg) and metadon (0.2 mg/kg) in preparation for surgery. Each animal received intramuscular Metadon (0.2 mg/kg), analgesic calprofen (4 mg/kg; subcutaneous), atropine (0.05 mg/kg; intramuscular injection), bronchial secretions, and antibiotics (8.75 mg/kg; Subcutaneous injection zh), dexamethasone (0.3 ml/kg; normal saline diluted 1:1; intramuscular injection). After the animals enter the operating room, they are perfused intravenously (femoral vein) with 1% propofol and diluted with lactated Ringer's solution, 125 mg ketamine (20 ml propofol, 40 ml lactated Ringer's solution, 1.25 ml ketamine). Deep anesthesia. Adjust the infusion rate to maintain the optimal level of anesthesia. During the entire operation, the anesthesia level and physiological state are controlled according to the arterial oxygen saturation, heart rate (ECG), ventilation and body temperature. Next, the animal is placed in a stereotactic frame and the head is fixed with a surgical ear bar. Apply a layer of local analgesic ointment on the ear stick to relieve the pain caused by immobilization. The local injection of lidocaine anesthetized the incision site. After the incision, the muscle tissue is pushed sideways to expose the skull, and a craniotomy (dlPFC) is performed above the frontal lobe. However, in order to reduce the impact of craniotomy, the size of the bone opening is minimized, so various grooves (such as arcuate grooves and main grooves) cannot be clearly identified, and the biopsy is accurate. I cannot guide you to the right place. It can be changed from one monkey to another monkey. The opening of the skulls of the three monkeys is on the left side (MK-LY, MK-MI, ML-LL) and on the right side of MK-MY. The size of the flap is about 1 square centimeter. After removing the bones, cut the dura mater, take out the dlPFC cortical tissue, and put it directly into the preservation solution. Burn damaged blood vessels, replace the flap and fix it with histological adhesive. Suture the muscle tissue and skin. After the operation, each animal was monitored until fully recovered. When monkeys eat normally, their symptoms are considered stable.

  Magnetic Resonance Imaging: Use MRI to locate the exact location of the biopsy and continue the MPTP follow-up procedure. First, each animal was lightly sedated with ketamine (10 mg/kg) and midazolam. After each monkey was transported to the MRI facility, 1% propofol was injected intravenously and diluted with Ringer's lactic acid solution and 125 mg of ketamine hydrochloride for anesthesia. Adjust the infusion rate to ensure the highest anesthesia level (continuous monitoring of ECG and oxygen saturation). In addition, place a hot water bottle with hot water around the monkey's body to maintain body temperature. The 3D transverse T1 weighted acquisition protocol was used to collect data on the GE3T magnet. The parameters are as follows: Field: 256 x 256, TR: 7.248, TE: 3.032, FS: 3. Due to the animal's prone position, the image is rotated. After proper rotation, the brain is extracted from the skull and represented in a three-dimensional view before display. Estimate the position and volume of each biopsy based on the MRI image (corresponding to gray). Please note that biopsy cannot be histologically verified. This is because when the MPTP treatment was performed, the second dlPFC biopsy was performed near the first biopsy. Therefore, before MPTP treatment, the two biopsies could not be distinguished, and only the first biopsy was related to current behavioral research. Results: The location and size of the biopsy: Based on MRI, the scope and location of the cortical biopsy were determined and reconstructed. The biopsy was transferred to the corresponding brain surface, and the volume of dlPFC biopsy was 7, 14, 16, and 7 cubic millimeters, respectively. In Mk-MY, the biopsy is located at the foremost end of the dlPFC, about 5 mm from the midline, and may overlap the transition zone between Brodman cortex 9 and 10. In addition, the Mk-LY biopsy was about 5 mm outside the midline, but closer to the caudal end, and appeared to be located in the nasal area of zone 9. MK-MI lesions are located in the dlPFC area. For the fourth monkey (MK-LL, considering that the biopsy does not include dlPFC, MKll should be considered an outlier here.

  Brinkman Board task improvement: The number of particles recovered in 30 seconds based on the behavioral score data of dlPFC shows that monkeys have basically stable hand agility before biopsy; data obtained from time-selective sequence analysis shows that monkeys are flat before biopsy. We have shown that we mainly follow a repeatable strategy (exercise habit) to empty. The time series visits 50 holes along the left and right axis. Interestingly, Figure 2a is shown by b in MK-MY, dlPFC or PMd-r biopsy does not affect the hole visiting score or time series. In fact, the scores before and after the biopsy are compared with the time series. Statistical analysis did not show any statistically significant differences. These conclusions apply to the ipsilateral and contralateral arms of the four monkeys, but apply to the other side of MK-MY. Increasingly removing the hand on the other side of the MK-Ly hand, the statistically significant difference indicates that the post-biopsy score is not sufficient, because the post-biopsy score is actually high and the lesions are "in the modified Brinkman "In the task, the dlPFC biopsy has the characteristics of this study. A larger and differently located biography than before (Area 46). ) Does not systematically affect performance and exercise habits

  Obtaining the withdrawal task: The results obtained by grabbing the withdrawal task from the arrival are R0, R3 and R5, which are divided into relative drawer opening resistance. For each resistance, the data is divided into two stages before biopsy and after biopsy; for each Hands, time before biopsy, time after biopsy, and time after biopsy are adjacent to each other for direct comparison. Quantitative data shows that resistance affects the maximum grip and maximum load before and after biopsy. , The maximum force increases parallel to the resistance. The greater the resistance, the greater the force required to grasp the knob or pull the drawer.