Fig. 2: Optical measurements of antagonism in OSN axon terminals.

a Experimental setup. Odor responses in OSN axon terminals were measured at olfactory bulb glomeruli through a cranial window. b Example image of glomeruli and selected ROIs from one of nine mice in this dataset. Responses for two odors (Methyl tiglate and Isobutyl propionate) and their mixture from selected glomeruli are shown on right as ΔF/F time courses. Colored circles correspond to ROIs in image. Red bar under traces denotes odor delivery time. Scale bar in image is 50 µm. c Example dose response curves from four selected glomeruli. Each point is the average of 3–5 trials. Odor concentrations are normalized to the largest measured concentration (see Methods). For each point, odor mixtures are the summation of both individual odors. d Data from 20 randomly selected glomeruli. Each point is the mean of the three largest responses from each odor. Error bars are SEM. e Left, comparison of the observed mixture response against the linear sum of both mixture components or (right) against the maximum response generated by either mixture component. f Cumulative distribution of rank-sum test P values obtained for 334 glomeruli for linear sum comparison (black) and comparison to maximum component response (grey). Red dots mark P values < 0.05. g Fraction of glomeruli that showed significant antagonism in each of six concentration bins. Each bin contains three adjacent concentrations.