Figure 3.

Stimulus Onset Asynchrony Makes a Mixture of Odorants with Differing Valences More Attractive

(A) Approach probabilities (determined by the half distance threshold) for the single odorants BN (A), BA (B), their synchronous mixture (AB), and their asynchronous mixture (B33A). Bars represent the mean. Vertical lines represent the 95% credible intervals. The lower-case letters represent significantly different responses to the odorant treatments (this dataset is pooled from experiments shown in D and E).

(B) Top: Flight trajectory of a flying fly (red) in the wind tunnel during stimulation with BN (A). Bottom: Visit probability maps for A (BN) and B (BA) and the synchronous (AB) and asynchronous (B5A, B10A, B33A) mixtures. The take-off platform (white circle), landing platform (white rectangle), and odor source (white star) are indicated for position reference. n = 44, 43, 41, 43, 45, and 45 for A, B, AB, B5A, B10A and B33A, respectively.

(C) Thresholding method that uses the distance that separates flies' approach probabilities for A and B best (maximized A-B difference threshold). Each point represents the proportion of A-stimulated flies that approached the target by the given minimum distance to the target minus the proportion of B-stimulated flies. The blue trend line was fitted using locally weighted scatterplot smoothing. The gray area indicates the 95% confidence interval. The distance at the peak of the trend line was defined as threshold (orange dashed line and value).

(D) Approach probabilities (determined by the maximized A-B difference thresholding method) of the experiment to test flies' limit to detect onset asynchrony. Stars represent significantly different responses between AB and the other mixtures. As A and B are used to determine the threshold, they were not included in the statistical analysis.

(E) Approach probabilities (maximized A-B difference thresholding method) of the experiment to test the effect of odorant order in asynchronous mixtures.

(F) Conditioning setup in which flies were left for autonomous differential conditioning. Flies can freely fly in the cage and enter the odorized tubes containing cotton wool soaked either with aversive salt solution or attractive sucrose solution.

(G) Approach probability for odorant mixtures with conditioned valences (maximized A-B difference thresholding). Odorants BD and EA were used equally as often as the CS+ and CS−.

See also Figures S2 and S3.