Social failure depression model and animal model of Alzhermer disease, development of experimental mode of learning and memory

Social defeated depression model (Social defeated)

In today's society, the stress events of depression are mainly social stress events. Therefore, the researchers made a social failure depression model in mice. C57BL/6J mice were placed in aggressively aggressive CD1 mouse cages 10 minutes per day for 10 consecutive days. After 10 minutes of contact, the C57BL/6J mice were separated from the CD1 mice with a vented transparent septum, and the C57BL/6J mice to be tested continued to receive stimulation for 24 hours. Control mice were separated from the same strain of mice, but the subjects were changed daily.  
After 10 days of modeling, the drug treatment was 7/14/28 days. At 24 hours after the end of dosing, the level of depression will be measured by detecting contact and evasion of C57BL/6J mice against the challenger. The experiment was carried out in the dark, and C57BL/6J mice were placed in a new environment with transparent ventilated cages to detect their activity in 2.5 minutes, and aggressive CD1 mice were placed in the next 2.5 minutes. . The time of the mouse in the contact area and other areas was analyzed using software, and the depression status of the control group and the drug group was evaluated accordingly.  

Novelty suppressed feeding test (NSF)  
Novelty suppressed feeding test (NSF): A test box with a height of 50 cm and a height of 40 cm was used to spread a 2 cm high wooden cutting box. The center of the box was placed with sugar pills or small pieces of food on white paper. Before the test, the animals were fasted for 24 hours. During the test, they were enlarged from any box angle/mouse into the box, observed by the camera system for 5 min, and the activity of the large/mouse was recorded. At the same time, the forefoot was lifted from the mouse to the mouse. When the sugar pill is eaten (latency). The activity of the large/mouse and the length of the eating time reflected the degree of anxiety/depression of the large/mouse, and then the animals were returned to the cage to record the food consumption within 5 minutes to rule out the effect of the difference in appetite on the eating time.  

Animal model of Alzhermer's disease

SD rats 200-250 grams. The animals were anesthetized with 3% sodium pentobarbital (35-40 mg/kg body weight) and fixed on a stereotaxic instrument (refer to the stereotaxic map of the whole brain of the rat). The previous 囟 was zero and the infeed coordinates were selected: 0毫米。 The front and rear coordinates (AP) 1.8mm, the midline side open (L) coordinates of 1.0mm, the ventral coordinates (v) 4. 0mm. First, use a dental drill to open the bone window at the above-mentioned coordinates, remove the skull, pick up the dura mater, and insert the self-made double-edged stainless steel blade (width 2 mm, thickness 0.1 mm) into the brain from the coronal plane according to the above coordinates. Then, move the knife outward by 1.5mm, then lower the knife by 1mm, and pull the knife up and down more than 10 times to completely cut off the curved seahorse umbrella. Finally, the blade is retracted to L1.0mm and the blade is withdrawn.  

Animal grouping  

1. Experimental group: 10, cut off the left hippocampus umbrella according to the above method;  

2. Sham operation group: 10, craniotomy and picking up the dura mater, cutting the cortex, but not cutting off the hippocampus umbrella, and finally suturing the scalp;  

3. Blank control group: 10, do water maze behavioral test and electrophysiological test. Morris behavior test with Morris water maze. (Provides two kinds of data) to locate the navigation capability.  

Development of experimental models of learning and memory

Pavlov believes that learning and memory are the process of establishing and consolidating conditioned reflex. The method of conditional reflex experiment he created has been widely used in the study of learning and memory. It is now called the classical conditional reflex method. In fact, the form of learning to remember billions is diverse, and the experimental mode of studying learning and memory is bound to be many. For example, operational conditioning (or instrumental conditioning) is an experimental model of the mountain in 1938. It is mainly applied to higher animals such as rats, cats, and monkeys. It is an animal that tries to actively learn an animal or Performing a set of operations is a more complicated conditional reflection mode. As another example, experimental models related to spatial memory have various labyrinths. In 1976, Olton proposed the eight-armed maze, a food-like behavioral model that led to the concept of working memory. This is a short-term memory form, a temporary information storage in the brain during certain cognitive behaviors. This memory has been found to depend on the function of the neural circuit of the prefrontal cortex of the brain. The biological significance of this memory is to adapt people to changing environmental conditions and accept new information that is constantly losing. In 1995, foreign authoritative authors commented on the neural basis of working memory. Well, working memory is usually to provide time and space continuity between past experience and current behavior. It is for thinking, playing chess, playing piano and unprepared. The speeches on the spot are all very important. In 1982, Morris created a Morris water maze to study spatial memory, which was mainly used to explore the function of the hippocampus. In summary, since Pavlov first created the classic conditioning model, many types of learning and memory experimental models have been developed.  

After a large number of experimental studies and clinical observations have been proved that different types of learning and memory have different neural structure foundations and different neural circuits involved, and there are multiple memory systems in the brain. The most obvious are two types of memory systems: one is cognitive learning and memory, also known as declarative learning and memory. This kind of memory enters the consciousness system, which is more specific and can be clearly described. Second, it is reflective. Procedural learning and memory, also known as implicit learning and memory, is a technical or sports learning memory. It is related to the development of habits and adaptive responses. Learning to avoid the need for awareness participation in the future, but a series of automated actions. .  



Irrigation System

Sprinkler irrigation and micro-irrigation automatic control equipment With the development of economy, water resources, energy shortage and labor cost increase, more and more water-saving irrigation systems will adopt automatic control. This article focuses on the advantages and classification of automated irrigation.

The advantages are as follows:

(1) It is possible to truly control the amount of irrigation, irrigation time and irrigation cycle in a timely and appropriate manner, thereby increasing crop yield and significantly improving water utilization.

(2) Saving labor and operating expenses.

(3) The work plan can be arranged conveniently and flexibly, and the management personnel do not have to go to the field at night or other inconvenient time.

(4) Since it can increase the effective working time every day, the initial capital investment in pipelines, pumping stations, etc. can be reduced accordingly.

classification:

First, fully automated irrigation system

The fully automated irrigation system does not require direct human involvement. The pre-programmed control procedures and certain parameters that reflect the water requirements of the crop can automatically open and close the pump for a long time and automatically irrigate in a certain order. The role of the person is simply to adjust the control program and overhaul the control equipment. In this system, in addition to emitters (heads, drip heads, etc.), pipes, fittings, pumps, and motors, it also includes central controllers, automatic valves, sensors (soil moisture sensors, temperature sensors, pressure sensors, water level sensors, and rain sensors). Etc.) and wires.

Second, semi-automatic irrigation system

In the semi-automated irrigation system, no sensors are installed in the field. The irrigation time, irrigation volume and irrigation period are controlled according to pre-programmed procedures, rather than feedback based on crop and soil moisture and meteorological conditions. The degree of automation of such systems is very different. For example, some pump stations implement automatic control, and some pump stations use manual control. Some central controllers are only one timer with simple programming function, and some systems have no central control. The controller, but only some of the sequential switching valves or volume valves are installed on each branch pipe.

Automated irrigation is the trend of the times. In the future water-saving irrigation projects, more and more automated irrigation systems will be applied.

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