Kinetlc Modeling Of Double Inputs With Spike-Timing Dependent Plasticity Tripartite Synapse

As the development of the Hebbian's learning rule,spike-timing dependent plasticity(STDP)of synapses is to describe the change of synaptic strength in the learning and memory process of different brain regions.According to the timings of pre-synaptic stimulation and post-synaptic stimulation,STDP can be divided into long-term potentiation(LTP)and long-term depression(LTD).With the deepening of people's understanding of astrocytes in brain tissue,the important role of glial cell in synaptic structure information transmission has also been taken seriously.However,for the study of STDP,the past modeling work focused more on the traditional synapses,which only consider the presynaptic neuron and postsynaptic neuron,ignoring the role of astrocytes played.In the study of plasticity of glial cell,however,previous work focused more on the influence of a single input signal on excitatory postsynaptic currents(EPSCs)to reflect the changes in synaptic plasticity,and lacked of research on the STDP mechanism in bi-stimulus inputs.Therefore,how to combine astrocyte and STDP mechanism is of great significance for strengthening the understanding of glial cells and STDP.Therefore,the main contents of this thesis include the following aspects:First,basing on classical neuron synapse model and empirical results,we propose a bi-stimulus inputs tripartite synapse(three units of presynaptic neuron,postsynaptic neuron andcastrocyte)model to describe the role of astrocytes in STDP mechanism of hippocampus.Through the simulation results of the model,the effect of astrocytes on the learning ability of synaptic structures is clearly demonstrated.We can conclude that the tripartite synapses relative to the traditional synapses have stronger learning ability,which also support the conclusions of previous experiments.Second,in addition,basing on the kinetic model of the tripartite synapse STDP plasticity mechanism proposed,we research on neurological diseases simply,especially Alzheimer's disease(AD)which has close relationship with tripartite synapse dysfunction,and predict the transformation of STDP windows under the dysfunction of postsynaptic membrane.We use the images obtained in the simulation of tripartite synaptic STDP plasticity model in the context of Alzheimer's disease to explain the pathological features of Alzheimer's patients and to explain patients' behavior.Our research will provide theoretical support for model studies of neurodegenerative diseases and help predict patient's behavior.