Tiandy multiple product levels are available to fulfill various demands. The Ultra Series is for professionals who demand the latest innovations and best quality. Pro series is for professional who looks for cost performance balance while Lite Series is for customers who care about quality but have a tight budget.
Network cameras are widely used in various applications and vertical industries. Face Recognition cameras can be used in entrance & exit, smart retail, public areas, and other scenarios to improve operation efficiency. ePoE with extended reach distance is widely applicable for stadiums, parking lots, etc., to save on cabling costs.
Customer prefer keywords :wireless camera , IP camera ,IP camera system, wifi camera,wireless cctv,PTZ Camera,cctv camera,cctv installation,cctv systems etc.
Network Ip Camera,Starlight Dome Camera,Dome Camera TF Card,Dome Network Ip Camera TD Cloud Security Co.Ltd , https://www.cctvcameraexpert.com
Effects of push-pull action on memory function in rats
Effects of push-pull action on memory function in rats
Abstract Objective: To investigate the effect of high G value exposure on memory function in rats after push-pull action. METHODS: Twenty-four male Sprague-Dawley rats were randomly divided into control group, +10Gz group and push-pull group, with 8 rats in each group. Changes in memory function of rats at different times after treatment were recorded. RESULTS: The number of errors and the error time of the push-pull group avoidance experiment increased significantly after exposure compared with the control group [6. 3 ± 1. 0), (2.3 ± 0.6) s, vs (0 0±0. 0) , (0. 0±0. 0) s ; 6 d are (0.3 ± 0.5), (1. 3 ± 0.9) s, vs (0.3 ± ± 0. 5) , (0. 1 ± 0. 2) s , ( P < 0.01)), also significantly increased compared with the + 10 Gz group; the latency was significantly shorter after the exposure than the control group (P < 0.01) ). The correct rate of the push-pull group maze test was (82. 5 ±4.6%) immediately after exposure, and (75. 0± 16. 0)% for 2 days, respectively, compared with the control group (92. 5 ± 4. 6 ) %, (100. 0 ±0. 0) % is significantly lower (P < 0.01). Immediately after exposure, the reaction was (33.6 ± 12.9) s, and 2 d was (67. 4 ± 32. 9) s, which was significantly prolonged compared with the control group and the + 10 Gz group (P < 0. 01). Conclusion: + 10 Gz exposure for 3 min after push-pull action can lead to severe persistent memory dysfunction in rats.
Keywords: acceleration, push-pull action, push-pull effect, memory
In recent years, the data shows that due to the continuous improvement of the maneuverability of fighters and the need for aggressive actions in air combat, push-pull maneuver (PPM) has an increasing chance of actual flight (1~3), which can lead to pilots. + Gz endurance declines, loss of consciousness is more likely than pure + Gz action. This phenomenon is called push-pull effect (PPE) [2, 3]. Since the 1990s, some fatal Class A flight accidents have been found to be related to the push-pull effect. This poses a serious threat to flight safety [3, 4]. Therefore, the push-pull effect has gradually been valued by people, and in recent years has become a new research hotspot in the field of aeromedical acceleration physiology. Previous studies have shown that high G exposure can cause cerebral ischemia, hypoxia, etc., resulting in decreased learning and memory ability [5,6], push-pull operation can reduce the high blood G value after exposure to lower cerebral blood flow. Therefore, the learning and memory ability may be reduced even more, but the current changes in the learning and memory function after the push-pull action have not been reported. The aim of this study was to investigate the effect of high G-value exposure on memory function in rats after push-pull action.
1 objects and methods
1. 1 Laboratory animals and grouping
24 male Sprague-Dawley rats (provided by the experimental animal center of our school), weighing (185 ± 10) g, were reared for 1 week and brought to the experimental environment to eliminate the effects of shock, environment and other factors on memory and behavior of rats. . Rats were randomly divided into control group, +10 Gz group and push-pull group, with 8 animals in each group.
1. 2 Experimental methods
1. 2. 1 Animal exposure method The animal centrifuge was used to simulate + Gz with a radius of 2 m. The rat was fixed horizontally on the arm of the centrifuge, and the head of the rat was oriented toward the axis of rotation of the centrifuge. The push-pull group was exposed to -1 Gz for 1 min, followed by + 10 Gz exposure, and the peak action time was 3 min. + 10 Gz group only exposed for + 10 Gz, the peak action time was also 3 min, and the acceleration growth rate was 1G·s-1. The control group was only placed in a plexiglass box for 3 min, but no + Gz exposure.
1. 2. 2 Avoiding darkness experiment [7] It is learned that the rats stay in the bright box for more than 5 minutes. After learning, the number of errors, error time and latency of the rats were recorded within 5 minutes. The timing of learning and memory measurements is the same as the Y-type labyrinth experiment.
1. 2. 3 Y-type labyrinth experiment [7] 9 times (90%) of the animals in 10 consecutive times are determined to be the standard of the society. After 2 h, + Gz exposure was performed, and then the correct rate of the rats and the changes required to complete the 10 tests were observed immediately after the end of the exposure, 6 h, 1 d, 2 d, 4 d, and 6 d. The test was carried out 10 times. The experiment time is from 8:00 to 12:00 am every day (6 h on the day of exposure, from 3:00 to 5:00 pm), under the same environment.
1. 3 Statistical analysis All data were expressed as mean ± standard deviation. The random unit group analysis of variance was performed using "SPSS 10. 0 FOR WINDOWS", and the t test was used for comparison between the two groups.
2 results
2. The changes in the number of errors, error time and latency of the rats in each group were observed in Table 1. The number of errors and the error time of the rats in the control group did not change significantly with the increase of the number of measurements; The number of errors and error time in the 10 Gz group was significantly higher than the baseline value at 6 h after exposure (P < 0.01), which was also significantly different from the control group (P < 0.01). The number of errors and the time of error were significantly higher than the baseline values ​​at 6 h and 6 d after exposure (P < 0.01), and also significantly increased compared with the control and +10 Gz rats (P < 0.01). The latency of the control group did not change significantly with the increase of the number of measurements. The latency of the rats in the +10Gz group did not change significantly after exposure. There was no significant difference between the time points and the control group. The incubation period of the rats in the push-pull group was exposed. After 6 h, 2 d, 4 d and 6 d, the baseline value was significantly shorter (P < 0.01), which was significantly shorter than the control group and the + 10 Gz group (P < 0.01).
2. 2 The correct rate and reaction time of the labyrinth experiment in each group
The correct rate of the control group increased with the increase of the number of measurements and then increased (P < 0.01). The correct rate of the rats in the + 10 Gz group decreased significantly compared with the baseline value immediately after exposure (2 days). P < 0. 01), there was no significant difference at each time point compared with the control group; the correct rate of the push-pull group was significantly lower than the baseline value immediately after exposure (P < 0.01). The control group was also significantly lower (P < 0.01). In the control group, the response time was gradually shortened compared with the baseline value (P < 0.01). The rats in the +10Gz group were significantly longer than the baseline value immediately after exposure (P < 0.05). Compared with the control group, it was significantly prolonged (P < 0.01). The response of the push-pull group was significantly longer than that of the control group immediately after exposure, 2 d and 4 d (P < 0.05), and also compared with the control group. And the + 10 Gz group was significantly prolonged (P < 0.05, P < 0.01, Figure 1).
3 Discussion
In recent years, fighters have been increasing their push-pull action during maneuvering. According to reports, in the United States from 1982 to 1996, the machine crashed or the serious G-LOC accident, 12.5% ​​of the accidents are likely to have push-pull action before the accident, 29% may have push-pull action, the stunt pilot experienced G-LOC 47% is obviously related to the push-pull effect [1, 3]. In the past, considering the low endurance of the human-Gz, there is no special anti-loading equipment on the aircraft, so the pilot should be asked to avoid doing the -Gz action. Modern tactics require fighters to attack each other with rapid action, and in order to reduce the chance of radar discovery, push-pull actions often occur in actual flight. Learning and memory are important brain functions essential for animals and human beings to survive. They are interrelated neural processes and external manifestations of nervous system activities, which can reflect the functional state of the nervous system. For human beings, it is the basis for intellectual activities. Learning refers to the acquisition and development of new behaviors (experiences), and learning to maintain and reproduce the experience is the memory. The Y-maze experiment is a method for detecting the ability of the visual and spatial position of rats to judge and recognize. The results of this experiment showed that the rats in the + 10 Gz group were significantly longer than the control group only after the exposure and immediately after the exposure, but there was no significant difference at the other time points compared with the control group and before the self-exposure. From the 1st day after + Gz exposure, the reaction of the push-pull group was significantly longer than that of the +10Gz group and the control group, and the correct rate was significantly lower than that of the + 10 Gz group and the control group, and did not return to normal until 4 days, suggesting that the push-pull After the action, + 10 Gz exposure for 3 min significantly reduced the memory capacity of the rats, and the decrease was most significant at 2 days.
In the dark-avoidance experiment, the number of errors and the error time of the push-pull group were significantly increased at 6h and 6d after exposure compared with the control group and the +10 Gz group. The incubation period was 6h, 2d, 4d and 6d after exposure compared with the control group and + The 10 Gz group was significantly shortened; while the number of errors and error time in the +10 Gz group was significantly increased compared with the control group at 6 h after exposure, and there was no significant difference in latency between the two groups. This indicates that the push-pull effect aggravates the effect of + Gz exposure on memory function in rats.
A large number of centrifuge tests have confirmed that the push-pull action can lower the +Gz endurance, slow the heart rate, decrease the arterial blood pressure, the basic impedance, and the total peripheral resistance reflectance, and increase the stroke volume [8, 9]. Analysis of the reason may be that at -1Gz, the blood is inertially displaced to the head, and the sharply elevated carotid blood pressure causes a strong nerve reflex of the carotid sinus and aortic arch baroreceptor, which enhances the central nervous activity and sympathetic central inhibition. The heartbeat is slowed down, the cardiac output is greatly reduced, and the total peripheral resistance is reduced, resulting in a decrease in heart level blood pressure. - After the end of 1 Gz, the above effects do not resolve immediately, so at the subsequent + 10 Gz effect, the head level blood pressure is more severe than when there is no pre--1 Gz effect. At the same time, because the central activity of the heart is still strong, the sympathetic center is still in a state of inhibition, and the baroreceptor of the carotid sinus area is affected by the reflex response of hypotension at this time. - 1 Gz not only reduced the head-level blood pressure at the subsequent + 10 Gz, but also impaired the body's compensatory response to + Gz, resulting in a significant reduction in cardiovascular function at + 10 Gz compared to -1 Gz, resulting in Ischemia and hypoxia in rat brain tissue is more serious, and even leads to ischemic changes of brain tissue neurons.
In conclusion, this study showed that + 10 Gz exposure for 3 min caused transient memory dysfunction in rats, and + 10 Gz exposure for 3 min after push-pull action resulted in persistent and severe memory dysfunction in rats, indicating push-pull effect The effect of + Gz exposure on memory function in rats was aggravated.
Source: http://