李朝义 张耀然 徐杏珍 宋如垓 阮迪云
中国科学院上海生理研究所. 上海 复旦大学生物系. 上海 中国科学技术大学生物系
摘要：用示波器产生亮度受正弦波调制的小光点刺激清醒猫外膝体神经元的感受野，以不同调制频率下神经元放电的平均频率为指标，分析了126个细胞感受野中心的时间频率调谐特性，主要结果如下:(1)大多数(93.7%)细胞呈调制一兴奋型反应，即刺激光的时间调制在一定频率范围内使放电频率增加，少数(6.3%)细胞呈调制一抑制型反应，即在一定频率范围内，时间调制使放电减少。(2)根据调谐曲线的形状和通带宽度，调制一兴奋型反应包括带通滤波器和低通滤波器两种类型，其110个调谐曲线的峰值分布接近正态曲线，多数细胞对7Hz的调谐最敏感。调制一抑制型反应包括带除滤波器和低除滤波器两类。(3)调制一兴奋型曲线的通带旁边较常出现抑制性侧带，调制一抑制型曲线出现兴奋性侧带。(4)感受野中心区与外周区的时间频率调谐曲线的带宽和形状有所不同。
A study of temporal frequency tuning properties of the cats lateral geniculate neurons
Abstract 126 lateral geniculate neurones were examined on unanaesthetized immobilized cats. The temporal frequency tuning curves of single neurones were measured by stimulating the cat's eye with a sinusoidally modulated light spot, generated on a CRT and presented to each neurone's receptive field center or its surround. The average discharging rate was used as an index to judge the sensitivity to different dulating frequencies. By comparing the mean impulse rates responding to modulated light stimulations (modulated discharge rate)with those responding to unmodulated light (unmodulated discharge rate), two opposite effects were observed. The majority of the cells (93 .7) %showed modulation-excitatory curves in which the modulated discharge rates were higher than the unmodulated ones. A minority of the cells. (6.3%) showed modulation-inhibitory curves in which the modulated discharge rates were lower than the unmodulated ones. The modulation- excitatory curves could further be grouped into two subtypes, the "band-pass filters" and the "lowpass filters". Similarly, the modulation-inhibitory curves could also be divided into two subtypes, the "band-rejection filters" and the "low-rejection filters". On both sides of the temporal frequency tuning curve subsidiary sidebands opposite in direction to the main part of the curves could often be seen, i.e. inhibitory sidebands flanking the modunation-excitatory tuning curve and excitatory sidebands flanking the modulation-inhibitory tuning curve. Most of the tuning curves have only one peak. Of the 110 curves measured the peak loci show a normal distribution which centered at 7 Hz. The tuning curves due to stimulation of different locations of the periphery were almost the same. But the tuning properties of the receptive field centers were different from those of the peripheries either in shape or in band-width.
