Figure 5. Mean gain control occurs primarily at transduction, and variance gain control occurs both at transduction and at the firing machinery.

(a) Transduction input-output curves from stimulus to LFP. Colors indicate increasing mean stimulus. Filters and projections are computed trial by trial. (b) Transduction gain, measured from the slopes of these input-output curves, decreases with the mean stimulus. The red line is a power law with exponent −1, (Weber’s Law). (c) Input-output curves for the firing machine module. (d) Firing gain does not change significantly with mean stimulus. (e) Transduction input-output curves for low (blue) and high (red) variance stimuli. (f) Transduction gains in the low variance epoch are significantly higher than transduction gains in the high variance epoch (p<0.001, Wilcoxon signed rank test) (g) Input-output curves of firing machinery during low variance stimuli. (g) Firing gain during low variance epochs are significantly higher than firing gains during high variance epochs (p<0.001, Wilcoxon signed rank test). Projections of stimulus are divided by the mean stimulus in each trial to remove the small effect Weber-Fechner gain scaling. Data in this figure is same as in Figures 3 and 4. (a,c,e,g) Mean across all trials. (b,d,f,h) Individual trials.

DOI: http://dx.doi.org/10.7554/eLife.27670.016

Figure 5—figure supplement 1. LFP responses to fluctuating Gaussian ethyl acetate signals with increasing mean.

Colors correspond to increasing mean odorant stimuli (purple…yellow). The data in this figure corresponds to the data shown in Figure 3. Increasing stimulus mean decreases the variance of the LFP responses, similar to the decrease in LFP responses seen in Figure 3c. Traces are mean subtracted.

DOI: http://dx.doi.org/10.7554/eLife.27670.017