Arle J E, Kim D O
Department of Surgery, University of Connecticut Health Center, Farmington 06030.
J Acoust Soc Am. 1991 Dec;90(6):3106-21. doi: 10.1121/1.401420.
Several circuitry schemes have been explored among model stellate and fusiform cochlear nucleus neurons in an effort to reproduce excitatory-inhibitory response-area (EIRA scheme) types I-IV. Single cell models incorporated known nonlinear membrane properties and spike-discharge characteristics, as described in previous modeling and intracellular recording. In addition, a unique method of implementing dendritic electrotonic distance processing was developed that provides greater computational efficiency, but with results similar to compartmental models. As an initial simple case, results were examined for a kHz pure tone. Auditory nerve (AN) population responses across characteristic frequencies from 200 Hz to 50 kHz based on actual single unit recordings were incorporated into the model as input. The findings and conclusions are (1) relatively simple inhibitory connections among stellate and fusiform cells, all of which receive AN excitatory inputs, can account for the salient features of EIRA-scheme types I-IV; (2) both types III and IV may be obtained using fusiform cells with small adjustments in the anatomical connections; (3) if stellate cells laterally inhibit their own neighbors, they can create inhibitory sidebands, but may have difficulty avoiding multiple sidebands; (4) in the model, type II cells are not responsive to broadband noise but rather to pure tones, and the reason for this was partly because the type II cells were inhibited by other CN units, and partly because the simulated AN fiber response to broadband noise was near their threshold; and (5) the type IV complex response areas may actually arise not necessarily because of elaborate circuitry, but as a result of a complex AN fiber population profile at high stimulus levels in conjunction with the type II inhibitory input to the type IV cells.
为了重现兴奋性-抑制性反应区域(EIRA模式)的I-IV型,人们在模型化的星状和梭形蜗神经核神经元中探索了几种电路方案。单细胞模型纳入了已知的非线性膜特性和动作电位发放特征,如先前建模和细胞内记录中所描述的那样。此外,还开发了一种独特的实现树突电紧张距离处理的方法,该方法提供了更高的计算效率,但结果与多房室模型相似。作为一个初始的简单案例,研究了对于1kHz纯音的结果。基于实际单单元记录的、跨200Hz至50kHz特征频率的听神经(AN)群体反应被纳入模型作为输入。研究结果和结论如下:(1)星状细胞和梭形细胞之间相对简单的抑制性连接,所有这些细胞都接受AN兴奋性输入,可以解释EIRA模式I-IV型的显著特征;(2)通过对解剖连接进行小的调整,使用梭形细胞可以获得III型和IV型;(3)如果星状细胞侧向抑制其自身的邻居,它们可以产生抑制性边带,但可能难以避免多个边带;(4)在模型中,II型细胞对宽带噪声无反应,而是对纯音有反应,其部分原因是II型细胞受到其他蜗神经核单元的抑制,部分原因是模拟的AN纤维对宽带噪声的反应接近其阈值;(5)IV型复杂反应区域实际上不一定是由于复杂的电路产生的,而是由于在高刺激水平下复杂的AN纤维群体分布与IV型细胞的II型抑制性输入共同作用的结果。