(a) Fluorescent signal changes recorded in the olfactory epithelium in the experiment shown in Figure 1e,f plotted here continuously over the entire duration of the experiment together with the distance of the fish to the cadaverine port at each point in time (color coding as in Figure 1f). (b) Control experiment in which water was injected instead of cadaverine with identical duration and settings to the experiment shown in Figure 1f,g. After the end of the 360 second baseline observation period, cadaverine was injected. Data are plotted analogously to Figure 1 and a. White scalebar represents 200 μm. (c) Additional cadaverine stimulation experiment run with a longer baseline than that shown in Figure 1f and showing again multiple visits to the cadaverine port with subsequent activations of oe. (d) The behavioral analyses show the median and the interquartile range of the mean duration of visits, as well as the mean swimming velocity in the left compartment before and after Cadaverine (Cad) delivery (100 μM). Cad reached the compartment via diffusion from a reservoir on the rim of the arena wall connected to the arena via a thin conduit (Wilcoxon matched-pairs signed rank tests, p = 0.0781, two-tailed (mean duration) and p = 0.023, two-tailed. (e) Representative heat maps of the behavioral traces for 3 different individuals during 2 minutes before (left) and after (right) delivery of cadaverine to the left compartment (purple shading in d). Black scalebar represents 2 mm.