SUMMATION AND MULTIPLICATION - 2 DISTINCT OPERATION DOMAINS OF LEAKY INTEGRATE-AND-FIRE NEURONS
SUMMATION AND MULTIPLICATION - 2 DISTINCT OPERATION DOMAINS OF LEAKY INTEGRATE-AND-FIRE NEURONS
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DOI：
10.1088/0954-898x/2/4/010
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发表时间：
1991-11-01
影响因子：
7.8
通讯作者：
BUGMANN, G
中科院分区：
文献类型：
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作者：
BUGMANN, G
泄漏积分激发 (LIF) 神经元的尖峰频率可以与大于或等于 2 的 n 个输入频率的总和或乘积成比例。本文从理论上定义了这两种操作模式的参数域（放电时间常数和突触权重）并通过仿真进行了研究。求和是基于分频原理，要求放电时间常数尽可能长。在此模式下，LIF 神经元会受到锁相效应的影响，并且对输入尖峰序列的不规则性不敏感。乘法基于符合检测并且需要更短的时间常数。仿真表明，乘法函数的质量会因输入尖峰序列的较大不规则性而降低，突触权重存在最佳值，并且随之而来的输入输出频率水平下降。在大脑中，从视网膜到更高皮质区域观察到的频率水平降低可能表明存在乘法型层。从生理学上来说，远处的突触可能主要参与求和，而近处的突触则用于乘法。有人提出学习涉及突触重新定位以及权重修改。
The spiking frequency of a leaky integrate-and-fire (LIF) neuron can be proportional to the sum or the product of a number n greater-than-or-equal-to 2 of input frequencies. In this paper, the parameter domains (discharge time constants and synaptic weights) for these two operation modes are defined theoretically and studied by simulations. Summation is based on the frequency division principle and requires discharge time constant as long as possible. In this mode, the LIF neuron is subject to phase locking effects and is insensitive to the irregularity of the input spike trains. Multiplication is based on coincidence detection and requires shorter time constants. Simulations show that the quality of the multiplication function decreases for large irregularities of the input spike trains, that there is an optimum value of the synaptic weights and that there is a consequent input-output frequency level drop. In the brain, the frequency level decrease observed from retina to higher cortical areas might indicate the presence of multiplication-type layers. Physiologically, distant synapses are probably mainly involved in summation while proximal synapses are used for multiplication. It is proposed that learning involves synaptic relocation as well as weights modification.