Hewitt M J, Meddis R
Department of Human Sciences, University of Technology, Loughborough, United Kingdom.
J Acoust Soc Am. 1994 Apr;95(4):2145-59. doi: 10.1121/1.408676.
A computer model is presented of a neural circuit that replicates amplitude-modulation (AM) sensitivity of cells in the central nucleus of the inferior colliculus (ICC). The ICC cell is modeled as a point neuron whose input consists of spike trains from a number of simulated ventral cochlear nucleus (VCN) chopper cells. Input to the VCN chopper cells is provided by simulated spike trains from a model of the auditory periphery [Hewitt et al., J. Acoust. Soc. Am. 91, 2096-2109 (1992)]. The performance of the model at the output of the auditory nerve, the cochlear nucleus and ICC simulations in response to amplitude-modulated stimuli is described. The results are presented in terms of both temporal and rate modulation transfer functions (MTFs) and compared with data from physiological studies in the literature. Qualitative matches were obtained to the following main empirical findings: (a) Auditory nerve temporal-MTFs are low pass, (b) VCN chopper temporal-MTFs are low pass at low signal levels and bandpass at moderate and high signal levels, (c) ICC unit temporal-MTFs are low pass at low signal levels and broadly tuned bandpass at moderate and high signal levels, and (d) ICC unit rate-MTFs are sharply tuned bandpass at low and moderate signal levels and flat at high levels. VCN and ICC units preferentially sensitive to different rates of modulation are presented. The model supports the hypothesis that cells in the ICC decode temporal information into a rate code [Langner and Schreiner, J. Neurophysiol. 60, 1799-1822 (1988)], and provides a candidate wiring diagram of how this may be achieved.
本文提出了一种神经回路的计算机模型，该模型可复制下丘中央核（ICC）中细胞的调幅（AM）敏感性。ICC细胞被建模为一个点神经元，其输入由来自多个模拟腹侧耳蜗核（VCN）斩波器细胞的尖峰序列组成。VCN斩波器细胞的输入由来自听觉外周模型的模拟尖峰序列提供[休伊特等人，《美国声学学会杂志》91, 2096 - 2109 (1992)]。描述了该模型在听神经输出、耳蜗核和ICC模拟中对调幅刺激的响应性能。结果以时间调制传递函数（MTF）和速率调制传递函数的形式呈现，并与文献中的生理学研究数据进行了比较。在以下主要实验结果方面获得了定性匹配：（a）听神经时间MTF是低通的，（b）VCN斩波器时间MTF在低信号水平下是低通的，在中等和高信号水平下是带通的，（c）ICC单元时间MTF在低信号水平下是低通的，在中等和高信号水平下是宽带通调谐的，（d）ICC单元速率MTF在低和中等信号水平下是锐带通调谐的，在高信号水平下是平坦的。展示了对不同调制速率优先敏感的VCN和ICC单元。该模型支持以下假设：ICC中的细胞将时间信息解码为速率编码[朗纳和施赖纳，《神经生理学杂志》60, 1799 - 1822 (1988)]，并提供了一个关于如何实现这一点的候选布线图。
