Koulakov Alexei, Gelperin Alan, Rinberg Dmitry
Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA.
J Neurophysiol. 2007 Dec;98(6):3134-42. doi: 10.1152/jn.00560.2007. Epub 2007 Sep 12.
We present a model for olfactory coding based on spatial representation of glomerular responses. In this model distinct odorants activate specific subsets of glomeruli, dependent on the odorant's chemical identity and concentration. The glomerular response specificities are understood statistically, based on experimentally measured distributions of activation thresholds. A simple version of the model, in which glomerular responses are binary (the all-or-nothing model), allows us to account quantitatively for the following results of human/rodent olfactory psychophysics: 1) just noticeable differences in the perceived concentration of a single odor (Weber ratios) are as low as dC/C approximately 0.04; 2) the number of simultaneously perceived odors can be as high as 12; and 3) extensive lesions of the olfactory bulb do not lead to significant changes in detection or discrimination thresholds. We conclude that a combinatorial code based on a binary glomerular response is sufficient to account for several important features of the discrimination capacity of the mammalian olfactory system.
我们提出了一种基于肾小球反应空间表征的嗅觉编码模型。在这个模型中，不同的气味剂激活特定的肾小球子集，这取决于气味剂的化学特性和浓度。基于实验测量的激活阈值分布，从统计学角度理解肾小球反应特异性。该模型的一个简单版本，其中肾小球反应是二元的（全或无模型），使我们能够定量解释人类/啮齿动物嗅觉心理物理学的以下结果：1）单一气味感知浓度的刚刚可察觉差异（韦伯比率）低至dC/C约为0.04；2）同时感知的气味数量可高达12种；3）嗅球的广泛损伤不会导致检测或辨别阈值的显著变化。我们得出结论，基于二元肾小球反应的组合编码足以解释哺乳动物嗅觉系统辨别能力的几个重要特征。
