A mathematical analysis of spatiotemporal summation of auditory nerve firings
A mathematical analysis of spatiotemporal summation of auditory nerve firings
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DOI：
10.1016/s0020-0255(98)10010-5
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发表时间：
1998-11-01
影响因子：
8.1
通讯作者：
Clark, GM
中科院分区：
文献类型：
--
作者：
Bruce, IC;Irlicht, LS;Clark, GM
许多听觉理论假设单纤维活动的时空组合形成听觉系统的重要特征。已经提出的解释感知性能的一种机制是听觉神经（AN）放电的时空总和。解剖学和生理学的研究发现，许多不同类型的细胞在尾核（CN），似乎执行这样的总结。本文的目的是从理论上确定不同程度的AN纤维收敛到CN中的求和神经元上将如何影响求和神经元输出的刺激特征的估计和区分。为了实现这一点，我们利用一个分析模型，基于AN活动的点过程表示，其中包括刺激属性的参数化措施。求和神经元模型允许任意程度的AN纤维收敛，从而便于研究不同求和神经元类型的声音神经编码理论的可行性。从模型中得到的结果表明，对于刺激频率在放电周期中的编码，输入纤维的最佳分布是非常窄的，时间积分是非常短的。这表明，AN纤维会聚到CN细胞表现出增强的同步起源于基底膜上的网站非常接近。相比之下，表现出降低的同步的CN小区类型在基于平均放电速率执行估计和辨别任务中可能是有用的。该模型表明，这可以通过非常广泛的投入和/或长期的时间整合来实现。我们假设，广泛分布的输入将优先于长期的时间整合，因为这将使神经元的输出能够跟随纤维群体的平均放电速率的快速变化。因此，可以通过这种求和神经元的输出的快速变化来检测刺激强度的瞬变，该瞬变产生纤维群体的平均放电速率的快速变化。(C)1998年爱思唯尔科学公司All rights reserved.
Many theories of hearing hypothesize that spatiotemporal combination of single-fiber activity forms an important feature of the auditory system. One mechanism which has been proposed to explain perceptual performance is spatiotemporal summation of Auditory Nerve (AN) firings. Anatomical and physiological studies have found a number of different cell types in the Cochlear Nucleus (CN) which appear to perform such summations. The purpose of this paper is to determine theoretically how various degrees of AN fiber convergence onto summing neurons in the CN would affect estimation and discrimination of stimulus features from the summing neurons' outputs. To achieve this, we utilize an analytical model, based on a point process representation of AN activity, which includes parameterized measures of stimulus properties. The summing neuron model allows for an arbitrary degree of AN fiber convergence, thus facilitating an investigation of the feasibility of theories of neural coding of sound for different summing neuron types. Results obtained from the model indicate that for coding of the stimulus frequency in the periodicity of firings, the optimal spread of input fibers is very narrow and temporal integration is very short. This suggests that AN fibers which converge onto CN cells exhibiting enhanced synchronization originate from sites on the basilar membrane very close together. In contrast, CN cell types which exhibit reduced synchronization could be useful in performing estimation and discrimination tasks based on the average discharge rate. The model indicates that this could be achieved by a very wide spread of inputs and/or long-term temporal integration. We postulate that a wide spread of inputs would be preferential to long-term temporal integration, because this would enable the neuron's output to follow rapid changes in the average discharge rate of a population of fibers. Consequently, transients in the stimulus intensity which produce rapid changes in the average discharge rate of a population of fibers could be detected by a rapid change in the output of such a summing neuron. (C) 1998 Elsevier Science Inc. All rights reserved.