Department of Bioengineering, University of Washington, Seattle, WA 98195, USA.
IEEE Trans Biomed Eng. 2009 Oct;56(10):2493-501. doi: 10.1109/TBME.2009.2016667. Epub 2009 Mar 16.
We have developed a biophysical model of a population of electrically stimulated auditory nerve fibers. It can be used to interpret results from physiological and behavioral experiments with cochlear implants and propose novel stimulation strategies. Our model consists of myelinated internodes described by a passive resistor-capacitor network, membrane capacitance, and leakage current at the nodes of Ranvier, as well as stochastic representations of nodal voltage-dependent channels. To approximate physiological properties measured in the auditory nerve (AN) of an acutely deafened cat, electrical parameters of the model fiber were chosen based on literature-reported values. Using our model, we have replicated the following properties within 10 % of the reported feline single-fiber measurements: relative spread (5.8 %), spike latency (630 micros), jitter (93 micros), chronaxie (238 micros), relative refractory period (4.6 ms), and conduction velocity (14 m/s). Moreover, we have successfully matched response characteristics of a population of fibers with the same number of diameter-distributed model fibers, enabling us to simulate responses of the entire AN. To demonstrate the performance of our model, we compare responses of a population of ANs stimulated with two speech encoding strategies, Continuous Interleaved Sampling and Compressed Analog.
我们开发了一种电刺激听神经纤维群体的生物物理模型。它可用于解释人工耳蜗的生理学和行为实验结果，并提出新的刺激策略。我们的模型由髓鞘化的节段组成，由被动电阻-电容网络、膜电容和Ranvier 结的漏电流以及节点电压依赖性通道的随机表示来描述。为了近似于在急性失聪猫的听神经（AN）中测量到的生理特性，根据文献报道的值选择了模型纤维的电学参数。使用我们的模型，我们在 10%的报道的猫科单纤维测量值内复制了以下特性：相对扩散（5.8%）、尖峰潜伏期（630 微秒）、抖动（93 微秒）、时程（238 微秒）、相对不应期（4.6 毫秒）和传导速度（14 米/秒）。此外，我们还成功地将具有相同数量直径分布模型纤维的纤维群体的反应特征进行了匹配，从而使我们能够模拟整个 AN 的反应。为了展示我们模型的性能，我们比较了两种语音编码策略（连续交错采样和压缩模拟）刺激的 AN 群体的反应。
