Duchamp-Viret P, Duchamp A, Sicard G
Laboratoire de Physiologie neurosensorielle, Université Claude-Bernard, CNRS, Villeurbanne, France.
Brain Res. 1990 May 28;517(1-2):256-62. doi: 10.1016/0006-8993(90)91035-f.
Until now, olfactory discrimination had never been investigated using stimuli delivered over a wide concentration range. However, the fact that intensity variations might influence qualitative discrimination has been suggested in numerous physiological and psychophysical studies. The aim of the present work was to investigate qualitative coding mechanisms when stimulus intensity varies. For this purpose, receptor cell and olfactory bulb neuron unit activities were recorded in response to 2-s pulse delivery of 4 odorants available at 20 discrete concentration values over a range from 1 x 10(-6) to 5.62 x 10(-2) of saturation. Two types of mathematical analyses, Pearson's r correlation coefficient calculation and principal component factor analysis, were applied to odor-evoked discharge frequencies. In both receptor cells and bulb neurons, qualitative discrimination abilities were found to increase with stimulus concentration. Furthermore, the results suggest that the olfactory bulb can send a discriminant and specific message at lower concentrations than the olfactory mucosa. The amplifying role of convergence of primary afferences onto olfactory glomeruli could account for this ability of the bulb neurons.
到目前为止，尚未有人使用在很宽浓度范围内递送的刺激物来研究嗅觉辨别。然而，众多生理学和心理物理学研究表明，强度变化可能会影响定性辨别。本研究的目的是探究刺激强度变化时的定性编码机制。为此，记录了受体细胞和嗅球神经元单元对4种气味剂的2秒脉冲递送的反应，这些气味剂在1×10(-6)至5.62×10(-2)饱和度范围内有20个离散浓度值。对气味诱发的放电频率应用了两种数学分析方法，即皮尔逊r相关系数计算和主成分因子分析。在受体细胞和嗅球神经元中，都发现定性辨别能力随刺激浓度的增加而提高。此外，结果表明，嗅球能够在比嗅黏膜更低的浓度下发送有区别的特定信息。初级传入纤维汇聚到嗅小球上的放大作用可以解释嗅球神经元的这种能力。
