A recent study by researchers of the Columbia University explored how neurons within the peripheral olfactory epithelium of a mouse’s nose responded to a series of odor mixtures. They observed that the presence of one odor could either enhance or suppress the response of a neuron to another odor, even if the modulating odor by itself did not elicit a response from the neuron. These suppressive and enhancing effects of particular odors within a blend occur at the peripheral sensory level, not at higher processing levels within the brain .
Lu Xu, Wenze Li, Venatakaushik Voleti, Dong-Jing Zou, lizabeth M. C. Hillman, Stuart Firestein (2020). Widespread receptor-driven modulation in peripheral olfactory coding. Science 10 Apr 2020, DOI: 10.1126/science.aaz5390