Kay Leslie M, Krysiak Magdalena, Barlas Lale, Edgerton Gabrielle Bloom
Department of Psychology, The University of Chicago, 940 E 57th St., Rm 331, Chicago, IL 60637, USA.
Physiol Behav. 2006 Jul 30;88(4-5):339-46. doi: 10.1016/j.physbeh.2006.04.007. Epub 2006 May 30.
Recent studies show that some features of odor perception are predicted by olfactory receptor biophysics and olfactory bulb physiology. Those studies used a behavioral assay in which rodents dig in a dish of scented cage bedding after pretraining to associate a buried reward with an odorant. The advantage of the digging task is an intensity measure of similarity (number of seconds spent digging). The method has the disadvantages of odorant contamination and low control over concentration and timing, making it difficult to use in electrophysiology. We describe an operant task that avoids these disadvantages and provides a reliable intensity-based similarity measure. Odorants can be delivered with a standard air dilution olfactometer, and rats learn to lever press to one odorant and avoid pressing to another in a Go/No-Go (CS+/CS-) task with a partial reinforcement protocol. Generalization tests substitute a portion of the unrewarded CS+ trials with test odorants. The number of generalization trials on which a subject responds to a test odorant is the measure of odor similarity intensity. We present validation tests using mixture component recognition, which show high repeatability, little variability across subjects and no decrease in responding across sessions. The results match those obtained with the digging task in four of five mixtures tested. This method allows optimal control over stimulus parameters and is compatible with simultaneous electrophysiological recording.
最近的研究表明，嗅觉受体生物物理学和嗅球生理学可以预测气味感知的某些特征。这些研究采用了一种行为测定法，即让啮齿动物在经过预训练将埋藏的奖励与一种气味剂联系起来后，在一盘有香味的笼垫中挖掘。挖掘任务的优点是提供了一种基于强度的相似性度量（挖掘所花费的秒数）。该方法存在气味剂污染以及对浓度和时间控制不足的缺点，这使得它难以用于电生理学研究。我们描述了一种操作性任务，该任务避免了这些缺点，并提供了一种可靠的基于强度的相似性度量。气味剂可以通过标准的空气稀释嗅觉计进行输送，并且大鼠学会在采用部分强化方案的“Go/No-Go”（CS+/CS-）任务中，按压杠杆以响应一种气味剂，而避免按压另一种气味剂。泛化测试用测试气味剂替代一部分无奖励的CS+试验。受试者对测试气味剂做出反应的泛化试验次数就是气味相似性强度的度量。我们使用混合物成分识别进行了验证测试，结果显示出高重复性、不同受试者之间的变异性很小，并且在各实验环节中反应没有下降。在测试的五种混合物中的四种中，结果与挖掘任务所获得的结果相匹配。这种方法能够对刺激参数进行最佳控制，并且与同步电生理记录兼容。
