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. 2024 Aug 12;49:bjae030. doi: 10.1093/chemse/bjae030

Fig. 3.

Fig. 3.

Relative onset timing in the millisecond range modulates ephaptic inhibition strength. (a) Top: Valve states for delivering 0.5-s long pulses of MHXE (blue) and HEPN (orange). Middle: Recordings from an ab3 sensilla in ten trials to low-concentrated odorants. Spikes from ab3A (blue) and ab3B (orange). Bottom: Instantaneous spike rates of ab3A (thin blue lines) and ab3B (thin orange lines) along with their means (bold lines). The moment the valve opened for the odorant pulses is marked as Time = 0.0. (b) True to scale temporal patterns of 0.5-s-long pulses of MHXE (blue, odorant A) and HEPN (orange, odorant B) in mixtures with varying stimulus onset asynchronies. (c) Transient responses, quantified as response peak rate, of ab3A (blue) and ab3B (orange) for all stimuli at low concentration across 7 flies. The spike rate is normalized to the cognate odorant response. Note the increase in inhibition, indicated by a lower firing rate, as onset time differences decrease towards the center. Circles show individual data points, horizontal lines show medians, boxes show interquartile ranges, and whiskers extend to ±1.5 times the interquartile ranges. Stars show significance levels for the comparison of each ORN’s response to the given stimulus and its response to the cognate stimulus alone, colored according to the tested ORN (two-tailed t-test, corrected for false discovery rate after (Verhoeven et al. 2005). *P < 0.05; **P < 0.005; ***P < 0.0005). (d) Same data as in (c), but only for ab3B, and pooling trailing and lagging onset time shifts (see Fig. S2 for the same analysis for ab3A). Data from 8 flies, each stimulus was presented 10 times. Each fly’s data is represented by a unique color. The colored lines show the linear regression for each fly (bold if P < 0.05), and the black line shows the average regression (r2 = 0.31, P < 0.0005). The positive slope shows that ephaptic inhibition increases with increasing synchrony between odorant onsets. A color version of this figure appears in the online version of this article.