(Scene Fear Experiment) Effect of Conditional Fear Training on Behavioral Activities in Rats

OBJECTIVE: To induce an anxiety response model and observe the effects of anxiety response on behavioral activities in rats. Method condition fear training, behavior detection. Results After 4 days of conditional fear training, compared with the control group, F344 rats increased the morphological response by 884% in the stupor behavior test (P<0.001), and the small-scale exploration exercise decreased by 88% (P<0. 001); In the elevated plus maze experiment, the number of access to the open wall and the residence time at the open wall decreased by 75% (P < 0.001) and 86% (P < 0.001) respectively; in the open field experiment, step on The number of grids and the residence time in the central grid were reduced by 47% (P < 0.001) and 60% (P < 0.05), respectively. Conclusion Conditional fear training can increase the anxiety response of rats and explore the decline of activity ability. It is an ideal method to induce anxiety response model.  
Key words: fear; conditioning; anxiety; F344 rat  
Because the location of brain regions related to anxiety is not clear, and there is no effective animal model, there are few basic research reports in this field in China. Davis found that animals trained by conditioning reflexes performed similarly to the symptoms and signs of clinically anxious patients. At present, conditionedfear training has become a classic method of inducing anxiety response and has been widely adopted by foreign scholars. In this experiment, this method was used to induce the anxiety response model in rats, and the effect of conditional fear training on behavioral activities in rats was observed.  
Materials and Methods  
I. Animals and grouping  
Pure male inbred F344 rats (purchased from Shanghai Experimental Animal Center), body weight 200-250g, randomized, 10 rats in each group, each rat was placed in a plexiglass cylinder and kept alone. Restricted, free access to drinking water, 12h bright / 12h dark, room temperature (22 ± 2) ° C.  
Second, instruments and materials  
The SEN23201 type electric stimulator, produced by Nihon Kohhden, Japan, connected to a electric shock cage (40cm × 40cm × 50cm), used to generate electrical stimulation, the electric shock cage wall is composed of plexiglass, the bottom of the cage is made of stainless steel wire, spacing 1. 2cm; low frequency The signal generator, produced by Jiangxi Electronic Instrument Factory, is connected to a speaker for generating sound of the corresponding specifications.  
Model ZS-KJ Scene Fear Conditioning (Near Infrared (NIR) Video Fear Conditioning)  

Third, animal model preparation  
An animal model of anxiety was created by electroporating the rat's sole to produce conditional fear. Cur fear condi2tioning training group: The rats were placed in an electric shock cage. Before the electric shock, noise was emitted from the speaker (75dB; 1000Hz; 5s), and the electric shock was given within the last 0. 5s of the noise. 5mA; 0. 5s), 1 time per minute, a total of 15 times, continuous training for 4d. Control group: Rats were placed in an electric shock cage with only noise and no electric shock. Other conditions were the same as those of the training group.  
Fourth, behavioral testing  
(1) Freezing Behavior: The stupor behavior caused by conditional stimulation (noise) was observed 48 hours after the last training. The main indicators are: (1) Stupor: keep the fixed position (except heartbeat and breathing); (2) explore the small-scale exercise: only the body and forefoot for exploratory exercise; (3) activity: hind limb activity, grooming, Stand up. (2) elevated plusmaze (elevatedplusmaze): observe and record the activity within 5min, observation indicators: (1) the number of closed arm entry (two front paws must enter the arm); (2) the number of open arm entry; (3) ) closed arm dwell time; (4) open arm dwell time. (3) Open field method (openfieldmethod): wooden box 100cm × 100cm × 50cm, the floor is divided into 25 squares 20cm × 20cm, the outer grid is called along the wall, and the rest is the central grid. Place the animals in the positive center and observe the activity within 12 minutes. Observation index (1) Number of crossings between squares: the number of times the three claws crossed into the adjacent grid; (2) The number of erection or modification: the number of times the forelimbs were more than 1 cm above the ground; (3) The residence time of the central grid. The latter two experiments were performed 24 hours after the end of the last training session.  
Fifth, statistical processing  
All experimental data were analyzed by SPSS 10. 0 statistical software and expressed by x±s. The mean of the two groups was compared using an independent sample t test.  
result  
I. Effect of conditional fear training on various indicators of F.  
Compared with the control group, the training group had a 894% increase in freezing response after conditional fear training (P<0.001), and a small-scale investigation exercise reduced by 88% (P<0.001), no activity behavior. which performed.  
Second, the influence of conditional fear training on the indexes of the elevated cross maze experiment of F344 rats  
Compared with the control group, the number of rats entering the development wall in the training group decreased by 75% (P<0.001), the retention time in the development wall decreased by 86% (P<0.001), and the number of entering the closed wall increased. The stay time increased, but these two were not significant differences.  
Third, the impact of conditional fear training on the indicators of F344 rat field experiment  
Compared with the control group, the number of treads in the training group was reduced by 47% (P < 0.001), and the retention time of the central compartment was reduced by 60% (P < 0.05). There was no significant change in the number of modifications.  
discuss  
Clinical anxiety disorders include both generalized anxiety and anaesthetic panic. These patients are mainly characterized by excessive anxiety, fear, behavioral evasion, and arousal. In fact, anxiety and fear are closely related. Fear is related to specific stimuli, while anxiety is a more generalized concept. We selected this inbred F344 rat to induce an anxiety response model through conditional fear training in order to observe the effect of anxiety response on behavioral activities in rats. For rodents, the stupor response is considered a reliable indicator of fear or anxiety. In F344 rats, the stupor response was significantly increased after a clear indication of conditional fear training, and the small-scale exploration of exercise and activity was significantly reduced. This suggests that by establishing repeated connections between conditional stimuli (sounds) and unconditioned stimuli (electric shocks on the soles of the feet), fearful conditioned reflexes have been established and F344 rats exhibit a strong fear response. The elevated plus maze test can be used to assess anxiety in rats. Montgomer believes that when rats are placed in the elevated plus maze, the rats are exposed to novel impulses, and the rats simultaneously generate impulses and fears of inquiry, which leads to the exploration-avoidance conflict behavior, which causes anxiety. From the experimental results, the rats in the conditional fear training significantly reduced the number of times they entered the open wall and the residence time in the open wall. In addition, according to our observation, the rats showed more anxiety-related behaviors in the closed wall, such as Stabilization, defecation, etc., all indicate that F344 rats after clear-tune conditioned reflex training showed significant anxiety. The open field experiment can reflect the inquiry activity and emotional response of rats. After conditional fear training, the number of treads in the rats and the residence time in the central compartment were significantly reduced, indicating that the rats' exploration activities decreased, which simulates the performance of clinical anxiety patients with behavioral evasion and decreased behavioral ability. In summary, conditional fear training is an ideal method to induce anxiety response models. However, this study only discussed the effects of anxiety response on behavioral activities in rats. The pathogenesis of anxiety disorders needs further study.  

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