Figure 4

Calcium responses in ORNs measured with multiphoton microscopy. (A) Example multiphoton-acquired images of glomeruli from an example Ano2^+/+ and Ano2^−/− animal, as well as example ΔF/F responses for five selected odors. Mean images from 20 frames preceding and during the odor delivery period were used. (B) Traces of the 50 largest (top) Ca²⁺ responses for Ano2^+/+ and Ano2^−/− animals across all odors and 50 randomly selected responses (bottom). (C) The 50 largest odor-evoked Ca²⁺ signals across all animals for each of 15 odors. Dashed line denotes odor onset and offset and red bar indicates odor duration. Molecular structures are depicted above. Bottom, mean response time course for each odor. (D) Cumulative distribution of the mean Ca²⁺ response in the odor period across all glomerulus-odor pairs (n = 2430 Ano2^+/+ and 2415 Ano2^−/− glomerulus-odor pairs, p < 0.001, Kolmogorov–Smirnov test). Inset, distribution of blank odor trial responses used to determine ROC threshold (threshold = 0.02 n = 162 Ano2^+/+ and 161 Ano2^−/− glomeruli, p > 0.05, Kolmogorov–Smirnov test). (E) Cumulative distribution of the mean Ca²⁺ response across all odors at each glomerulus (n = 162 Ano2^+/+ and 161 Ano2^−/− glomeruli, p < 0.001, Kolmogorov–Smirnov test). (F). Mean response of all glomeruli responding above threshold for each odor (Wilcoxon rank-sum test with Bonferroni correction, *p < 0.05, **p < 0.01, ***p < 0.001). (G) Scatter plot of population sparseness for each odor. Mean across all odors is the filled black circle (mean sparseness = 0.09 ± 0.02 in Ano2^+/+ and 0.13 ± 0.02 in Ano2^−/−, p = 0.002, Wilcoxon sign-rank test). (H) Histogram of lifetime sparseness across all glomeruli (mean sparseness = 0.28 ± 0.01 in Ano2^+/+ and 0.28 ± 0.01 in Ano2^−/−, p = 0.89, Wilcoxon rank-sum test.