Study On The Amygdala Cluster Encoding In The Formation Process Of The Rat’s Visual Conditioned Fear

Vision is the main channel for mammals to obtain external information, at least more than 80% of the perceptual information is obtained through the vision of the animals. when animals see the cause of fear or aversion to the visual target will produce strongly physiological and psychological stress and with the escape behavior, it can evoke visual information regulation center and stimulate animals to protect themselves instinctly. Animal’s fear of the external visual information is acquired through two ways: Congenital heredity and acquired acquisition. The innate visual fear is inherited to the descendant and it has the function of unconscious self protection. However, animal survival facing all kinds of potential threats, most animals need to learn continuously and accumulate the life experience in the growth process, so as to obtain the conditioned fear visual association. The amygdala is located in the medial temporae lobe, which belongs to the early evolution of marginal structure. A large number of studies have indicated that the amygdala plays a key role in the formation and expression of fear. Therefore, to carry out the amygdala in fear conditioned visual established in the process of coding research has important significance to study the early warning mechanism of the brain.Currently in the amygdala neurons cluster encodes fear of information research, it is not clear the amygdala in conditioned fear visual establishment of spike response and neuron LFP signal dynamic connection characteristics. Therefore, the paper awakes Long Evens rats as an animal model to establish animal conditioned fear visual association with Pavlov conditioned reflex theory, through animal behavior and electrophysiological experiments combining method, application multi-channel neuronal discharge recording technique collected rats conditioned fear visual neurons in the amygdala response signal was established, respectively, the spike and the LFP signal study rats conditioned fear vision building process in fear of visual information cluster coding. The main contents and results of this paper are as follows:(1) Developing a visual conditioned fear training device. Firstly, training device of PC visualization software is developed by using VB to design, device control subsystem is developed based on C8051F320, and the USB communication protocol realize two-way communication between the two, so as to realize the automation training. Secondly, according to the demand of the experiment design training program and definition of active avoidance training effect of quantization rate. Finally, develop the device applied to practical training.(2) The fear in the process of the establishment of the amygdala encoding characteristics of fear information based on spike signal. Firstly, the design of the visual stimulus signal stimulation patterns collected spike signals are preprocessed. Then, extract neuronal clusters distributed rate and cluster entropy feature in rats fear visual association established process in three stages(before training,in the training and after training), the fear vision established in the process of amygdala based on spike fear information encoding characteristics; Finally, the support vector machine constructs a visual information classification model to realize visual fear of different stages of training fear encode visual information verification.(3) The fear of vision in the process of the establishment of amygdala LFP theta bands signal neuron clusters of functional connectivity encoding characteristics. Firstly, the wavelet packet transform, extracted from rat amygdala established in fearful visual process in the local field potential theta band(4-8Hz); Then, the phase delay index to quantify the fear visual training process at different stages of amygdala neuron clusters function connection strength and extract functional connectivity of the average path length and the average clustering coefficient and average linkage intensity of the three characteristics, the fear in the process of amygdala LFP response signal of the theta frequency band fear information encoding characteristics; Finally, the support vector machine constructs a visual information classification model to realize visual fear of different stages of training fear encode visual information verification.