How are odors represented in the higher processing areas of the brain? Zou and Buck compared the responses of mouse olfactory cortical neurons to binary mixtures of odorants versus their individual components. They monitored neuronal activity in the anterior piriform cortex of the same animals in response to individual odors and mixtures. The technique used enabled the authors to monitor neuronal activity in response to two temporally segregated experiences. The results suggest that olfactory cortical neurons receive convergent input from multiple odorant receptors and that a subpopulation may require such convergent input for activation.