The Joint Regulation Of Excitatory And Inhibitory STDP Plasticity To The Cortical Neural Circuits

The development of information technology makes the research of working mechanism of the cortical network more important,yet the processing information mechanism of the cortex neural network is still not fully understood.Thus it is very meaningful to study the cortical neural network modeling and simulation by the numerical method.The cortex neural network model based on spiking neurons can well simulate the synaptic adjustment process and the discharging characteristic of the cortical network,which helps explain information regulation and control mechanism of the biological neural system.Spiking timing dependent synaptic plasticity-STDP mechanism in the biological neural system has an important significance in learning,memory reproduce and neural information processing.STDP can be divided into excitatory STDP synaptic plasticity and inhibitory STDP synaptic plasticity.Excitatory STDP synaptic plasticity has important significance on the signal input channel selection and on the regulation of synaptic weights distribution.Inhibitory STDP synaptic plasticity has important significance on the handing of neural information and on the processing of neural circuits.This paper studied the joint regulation of excitatory and inhibitory STDP plasticity to the cortical neural circuits.The main work is as follows:(1)The discharge characteristics,synchronization characteristics and the learning process of the synaptic strength of the network were studied in the typical cerebral cortex circuit model with both excitatory and inhibitory STDP synaptic plasticity.It were found the average strength of the four different synaptic connections was stable,so as to ensure the stable discharging of the network and the synchronization of the neurons.When the inhibitory learning rate increased,the synchronization of the neurons of the cortical network and the discharge rate increased,also enhanced the whole strength of the inhibitory synapses,weakened the whole strength of the excitatory synapses,which embodied the regulation of excitatory and inhibitory of the cortical network.(2)The influence of discharge characteristics of neuron clusters were studied when the connection probability was changed between neurons with both excitatory and inhibitory STDP synaptic plasticity,for the three different learning windows of the inhibitory STDP synaptic plasticity mechanism.The average discharge,synchronization,synaptic electricity and synaptic value were calculated in the different inhibitory STDP synaptic mechanism.By contrast,it was found that the discharge of neuron cluster had been controlled when the connection probability between neurons was large in the type of inhibitory STDP synaptic plasticity Hebbian and Symmetric.It could maintain normal discharge of the cluster of neuron with the influence of both inhibitory STDP synaptic plasticity of anti-Hebbian learning window and excitatory STDP synaptic plasticity of Hebbian learning window by regulating the different types of the synaptic connection strength.(3)The influence of discharge characteristics of neuron clusters were studied when the inhibitory learning window rate of inhibitory STDP synaptic plasticity mechanism was changed between neurons with both excitatory and inhibitory STDP synaptic plasticity,for the three different learning windows of the inhibitory STDP synaptic plasticity mechanism.By contrast,it was found that the discharge rate and synchronization of neuron had been enhanced when the inhibitory learning rate was large in the type of inhibitory STDP synaptic plasticity Hebbian and anti-Hebbian.There is no obvious change of discharge characteristic when the inhibitory learning rate changed in the type of inhibitory STDP synaptic mechanism.