Figure 2: SlitOR response spectra at high-stimulus doses.
(a) Heat map summarizing the mean responses (n=5 or 10) of 17 SlitORs to the panel of 51 odorants at high dosage (10 μg per pipette for pheromone compounds, 100 μg for the other compounds). Responses are colour-coded according to the scale on the right (firing rate in spikes s−1). SlitORs are classified based on a cluster analysis of response spectra (see dendrogram at the top) and odorants are classified depending on their chemical class (magenta, aromatics; cyan, terpenes; orange, aliphatics; black, unclassified). (b) Tuning curves of SlitORs, showing the distribution of mean responses (n=5 or 10) to the panel of 51 odorants at high dose. The tuning breadth of each receptor is represented by the sparseness value of the distribution (S)31. A low S value indicates a broad tuning and a value of 1 indicates a narrow tuning of the receptor. (c) Bubble plots representing the distribution of OR responses in S. littoralis, D. melanogaster and A. gambiae among a virtual odour space based on physicochemical properties of the molecules. Odorants are distributed along the first two components from a PCA of the 32 normalized molecular descriptors described in ref. 62 and the size of each bubble is scaled to the capacity of the considered OR repertoire to detect the odorant. Colours represent the different chemical classes, as in a.
