Abstract
Interpreting chemical information and translating it into ethologically relevant output is a shared challenge of olfactory systems across species, but are olfactory computations conserved across species to overcome these common challenges? To investigate this, we compared neural activity in the locust antennal lobe (AL) and mouse olfactory bulb (OB) both during and after odor presentations. We found that odors activated nearly mutually exclusive neural ensembles during odor presentations ("ON response") and after the termination of the odor stimulus ("OFF response"). ON and OFF responses evoked by a single odor were anticorrelated with each other. Inverted OFF responses persisted long after odor termination in both AL and OB, and enhanced contrast between odors that were experienced close together in time. Together our results show how post-odor neural activity, relative to odor-evoked activity, is similar across two distinct species, revealing a conserved mechanism for enhancing contrast between odors at the neural level.