AMPLIFYING ROLE OF CONVERGENCE IN OLFACTORY SYSTEM A COMPARATIVE-STUDY OF RECEPTOR CELL AND 2ND-ORDER NEURON SENSITIVITIES
AMPLIFYING ROLE OF CONVERGENCE IN OLFACTORY SYSTEM A COMPARATIVE-STUDY OF RECEPTOR CELL AND 2ND-ORDER NEURON SENSITIVITIES
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DOI：
10.1152/jn.1989.61.5.1085
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发表时间：
1989-05-01
影响因子：
2.5
通讯作者：
VIGOUROUX, M
中科院分区：
文献类型：
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作者：
DUCHAMPVIRET, P;DUCHAMP, A;VIGOUROUX, M
1. 在蛙体中记录了作为输出细胞的二级神经元受体细胞的胞外单一反应。采用多级动态流动稀释嗅觉计，将四种确定浓度分布在大范围内的气味剂以2秒平方脉冲的形式输送到嗅觉粘膜。在两种情况下研究了球的反应，刺激被传递到腹侧或整个粘膜。2. 比较细胞的总体反应性。对于二级神经元，反应比（兴奋或抑制）明显取决于刺激的条件，当整个粘膜受到刺激时，球反应比只受到腹侧粘膜刺激时的反应比增加。此外，当刺激传递到整个粘膜时，发现球的兴奋率与受体细胞和二级神经元的兴奋率相似。3. 反应阈值是通过比较刺激前30秒和刺激后12秒的峰间间隔值来确定的，使用Mann-Whitney U检验（表2）。受体细胞的反应阈值随刺激浓度的分布与二级神经元受腹侧粘膜刺激时的反应阈值分布无显著差异。这两种分布与刺激整个粘膜的二阶神经元的分布明显不同。在最后一个实验条件下，球神经元表现出提高的敏感性。4. 在整个浓度范围内，整个招募过程是连续的，以细胞对兴奋反应的累积百分比作为浓度的函数来表示。在球水平，当整个粘膜受到刺激时，招募的浓度低于仅刺激腹侧粘膜的浓度。在最后一种情况下，球招募的动态与受体细胞的动态没有区别。5. 我们进一步研究了受体细胞和二级神经元在每种刺激下的招募过程。在不同的刺激中发现了招募的差异，至于球神经元，它们取决于刺激的条件。6. 这些结果的主要结果是证明受体细胞向二级神经元的收敛在功能上涉及嗅觉初级信号的放大过程。（摘要删节为400字）
1. Extracellular unitary responses of receptor cells of second-order neurons identified as output cells were recorded in the frog. Four odorants of defined concentrations distributed over a wide range were delivered in the form of 2-s square pulses to the olfactory mucosa with a multistage dynamic flow dilution olfactometer. Bulbar responses were studied under two conditions, the stimuli being delivered either to the ventral or to the entire mucosa. 2. Overall responsiveness of the cells was compared. For the second-order neurons, the response ratio (excitation or inhibition) clearly depended on the condition of stimulation when the entire mucosa was stimulated, the bulbar response ratio was increased, as compared with that obtained when only the ventral mucosa received stimuli. Furthermore, when the stimuli were delivered to the whole mucosa, the bulbar excitation ratio was found to be similar to those of receptor cells and second-order neurons. 3. Response thresholds were determined from a comparison of the interspike interval values in the 30-s pre- and in the 12-s poststimulus time periods, using the Mann-Whitney U test (Table 2). The distribution of response thresholds of receptor cells as a function of stimulus concentration did not significantly differ from that of second-order neurons as excited by stimulating the ventral mucosa. These two distributions differed significantly from the distribution of second-order neurons as stimulated through the entire mucosa. In this last experimental condition, the bulbar neurons displayed an improved sensitivity. 4. The overall recruitment process, represented by the cumulative percentage of cells responding with excitation as a function of concentration, was found to be continuous over the entire concentration range. At the bulbar level, when the entire mucosa was stimulated, the recruitment occurred at lower concentrations than when only the ventral mucosa was stimulated. In this last case, the dynamics of the bulbar recruitment did not differ from that of receptor cells. 5. The recruitment process was further studied for each stimulus, for receptor cells as well as for second-order neurons. Differences in recruitment were found between stimuli and, as for the bulbar neurons, they depended on the condition of stimulation. 6. The main outcome of these results is the demonstration that the convergence of receptor cells onto second-order neurons is functionally implicated in an amplification process of the primary signal in olfaction.(ABSTRACT TRUNCATED AT 400 WORDS)