Coding of periodic pulse stimulation in chemoreceptors

In natural conditions odorants released continuously by animals and plants are broken in discontinuous clumps and filaments. In the case of flying insects these discontinuities are perceived as periodic variations in the concentration of the stimulus. This periodicity has been shown to be essential to orientation and location of mate and food. We study analytically and numerically a model of the receptor-ligand interaction that takes place in the receptor neurons. We show that this model can account quantitatively for the range of optimum stimulus frequencies measured experimentally in the sex-pheromone system of moths. The results obtained suggest that the rate constants characterising the pheromone-receptor interaction are optimally adapted to the temporal characteristics of the signal it perceives.