Fig. 7
From: Asymmetric ephaptic inhibition between compartmentalized olfactory receptor neurons
An electric circuit model for compartmentalized ORNs. a Passive electric circuit model of a sensillum consisting of two ORNs and an auxiliary cell (gray rectangle). b Simultaneous fitting of the LFP responses of the ORNs housed in the ab3, ab4 and ab5 sensilla. Identical parameters were used for all ORNs, except for the morphometric parameters and odorant sensitivity, which are ORN-specific and determined based on the experimental data whenever available. Each curve describes the dose−response relationship of an ORN when activated by a private odorant. Empty circles indicate measured LFP responses. Odorant concentrations are plotted logarithmically on the x-axis. c Simulation of ORN depolarization (ΔVm) in relation to the LFP response. d, e Simulation of the transmembrane potential of the ab4 ORNs (Vm) when either ab4A (d) or ab4B (e) was activated by increasing concentrations of private odorants. Two different activation states of the neighboring ORN (0 and 50%) were considered. Depolarization of one ORN (“active”, solid line) ephaptically hyperpolarizes its neighbor (“ephaptic”, dashed line). ΔVmA and ΔVmB: maximal change in Vm (mV) for ab4A and ab4B, respectively. A/B or B/A: the absolute value of ΔVmA/ΔVmB (A/B) or ΔVmB/ΔVmA (B/A). f Simulation of the LFP responses and transmembrane potential changes of the ab4 ORNs, assuming that both ORNs express the same odorant receptor, Or56a. Except for ab4A odorant sensitivity, all fitting parameters are as in b for ab4. Blue: large-spike “A” ORN. Orange: small-spike “B” ORN. See Methods for details on modeling, data fitting and parameters. Source data are provided as a Source Data file. ORN olfactory receptor neuron, LFP local field potential
