The Performance of Dogs in Detecting Alpha-Ionone in the Vapor Phase.

摘要

Concentration-response functions for alpha-ionone were established for four German shepherds. The dogs were tested in a three choice behavioral apparatus and trained, by a restricted operant procedure, to establish an approach-avoidance discrimination between odor and air. Odorant concentrations were presented from an olfactometer calibrated by gas chromatography. Minimum detectable concentrations fell within the range *4 x 10 to the 4.5th power -4 x 10 to the 6.5th power molecules/cc. Concentration-response curves for three of the dogs show a clear double reversal in slope which is statistically significant and which divides the curve into a slowly descending upper limb, best fitted by a parabolic function, and a rapidly descending lower limb, best fitted by a cubic function. There is evidence that this division might reflect a dual receptor mechanism. When performance during testing stabilized for a given concentration and the concentration was then lowered by a certain magnitude, the new performance level depended markedly on that magnitude. No evidence was found to suggest that adaptation to the test odor influenced performance. As defined by a differential threshold fraction (delta Flow/Flow) one dog's ability to discriminate between differences in flow rate fell in the range of 0.12-0.08. (Author)