基于模型的耳蜗核神经元反应类型随着刺激强度的变化(英文)

Changes of response patterns to excitatory stimuli of different intensities: a model-based study of cochlear nucleus neurons

目的耳蜗核神经元响应短纯音刺激的反应类型主要有类初级反应型、梳状型和给声开始型。我们建立的兴奋性模型可以仿真出耳蜗核神经元的反应类型,本文在此基础上研究兴奋性输入强度对耳蜗核反应类型的影响,并推测生理情况下抑制性输入在神经元响应中的作用。方法在Matlab平台上构造基于积分-放电模型的兴奋性模型,改变其输入强度,多次重复刺激后用OriginPro 7.5数据分析软件获得其刺激后时间直方图,观察神经元的反应类型是否随刺激强度发生改变。结果仿真发现随着兴奋性输入强度的增加,初级反应型只增加放电数,梳状型和给声开始型还出现向初级反应型转变的结果,而生理条件下很少观察到耳蜗核神经元随着刺激强度的变化而改变其反应类型。结论基于仿真结果和生理实验的比较,推测耳蜗核神经元接收到的不是单一的兴奋性输入,抑制性输入对神经元响应声音刺激时将膜电位稳定到一定范围起着重要作用,这种多种输入整合的共同作用最终决定神经元的反应类型和响应特性。

Objective The cochlear nucleus （CN） neurons show 3 principal response patterns to short tone bursts, namely the primary-like, chopper and onset response patterns. We previously established an excitatory model to simulate the response patterns of CN neurons to stimuli. In this study, we aimed to investigate the effects of excitatory intensity on the CN neuron response patterns and explore the role of inhibitory inputs under normal physiological conditions. Methods Based on the platform of Matlab and the excitatory model derived from the integrate-and-fire model, we altered the intensity of excitatory inputs in dB range and obtained the histograms to analyze the changes in the response patterns of the neurons using OriginPro 7.5 data analysis software. Results The original primary-like response pattern of the neurons did not vary significantly while the chopper and onset response patterns changed into primary-like responses with the increase of the excitatory input intensity. But this response pattern alteration as a result of excitatory input intensity changes was rarely observed under normal physiological conditions. Conclusions The CN neurons receive balanced excitatory and inhibitory inputs, which stabilize the neuronal membrane potential within a limited range. The balanced inhibitory inputs decide the response pattern of a given neuron.