New studies on odour discrimination in the frog's olfactory receptor cells. II. Mathematical analysis of electrophysiological responses

Revial et al. (1982) reported the experimental findings obtained in cell units stimulated with two new sets of odorants. The present paper deals with mathematical processing of these electrophysiological data. The multidimensionality of the odour space was confirmed. Camphor, isoborneol and cineole appeared to represent a ‘camphor group’ markedly discriminated from other odorants. A‘terpene group’ including terpinene, dimethylstyrene, limonene and cymene and related to menthane and menthene was observed. A series of 8 cycloketones was found to have a linear pattern in the factorial planes and to be subdivided into three subsets. Cyclooctadecanone and cyclotetradecanone displayed correlations and spatial relationships with musk ketone while cycloundecanone, cyclodecanone and especially cyclononanone were more related to the‘camphor group’. Separate processing of the unitary responses of 12 receptor cells recorded from a single preparation led to the building of a factorial space resembling that constructed with the full collection of data. The incidence of odorant concentration on similarity evaluation is discussed on the basis of receptor responses to two different concentrations of some of the odorants.