| Objective: The aim of this thesis is to research the theory and feasible method for Alzheimer' s disease(AD) with rat model by microinjecting AB into cerebrum, to explore the ability of learning and space memory of AD rats by performing Morris water maze behavior examination, and to analyse the AD electroencephalography(EEG) frequency characters via frequency analysis of EEG in the brain area related with cognitive areas of rats. The AD rat is successfully modeled and verified by behavior examination and EEG frequency characters analysis at cerebral areas related with cognitive function in rats brain. Methods: To model the Alzheimer' s disease for rat, the AB was microinjected into hippocampal CA1 area. Two weeks later, Morris water maze behavior examination was performed, which included 5-day place navigation with a fixed platform randomly placed in one quandrant, and spatial probe test without platform. The related data, such as movement time, movement distance, and the memory percentage for the platform quandrant etc, was recorded. Respectively compared with the average of the normal rats' movement time, 4 of the 7 modeled rats with different dementia degree were chosen from the madeled rats, with 1 mild and 3 medium dementia. The EEG in the brain areas related with cognitive function (frontal lobes, occipital lobes and temporal area) were recorded in both normal and AD rats, to analyse the power spectrum and to study the AD EEG frequency feature of the AD model rats.Results:1. 7 rats in model group were microinjecte AB into the cerebrum. Based on the dementia chosen criteria, 1 of 7 model rats was the moderate dementia and 3 of 7 were mild dementia. The success rate of the AD rats is 57. 1% in this research.2. The main results of Morris water maze behavior examination are as follows:(1)place navigation: The movement time of the AD rats is markedly more than that of normal, the movenment distance of the AD rats is highly longer than that of normal, and the platform memory percentage of the AD rats is much lower than that of normal. The search points and the memory mark are also less than normal.(2)Spatial probe test: The movement distance in AD rats is obviously longer than that of normal, its time percentage of the original platform quandrant is low compare with the normal.3. The EEG frequency feature in the cerebral cognitive areas in two groups are as follows:The a -band power of EEG decreased in AD rats, with slower frequency. The power of the -band and the -band increased significantly. Conclusions:1. In the study the success rate of making AD model is 57.1%, showing that the microinjection of AB into rat cerebrum is an effect and feasible method for modeling the AD rats. This results supported the hypothesis in some degree that the AB deposition would lead to theneural system damaged as well as dementia.2. The results of Morris water maze behavior examination shown that the movement time could be used as a choosing criteria for AD rats, and that the learning and memory of the AD rats decreased notably compared with the normal rats.3. With the analysis of the frequency features of the EEG in brain areas, which is related to cognitive function, of AD rats, EEG features could be seen as such: the rhythm of the a wave were slowed down, its power decreased or even disappeared. Activaties of the slow waves( band and band) increased, with the power raised.
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