▪ Abstract We examine early olfactory processing in the vertebrate and insect olfactory
systems, using a computational perspective. What transformations occur between the first
and second olfactory processing stages? What are the causes and consequences of these
transformations? To answer these questions, we focus on the functions of olfactory circuit
structure and on the role of time in odor-evoked integrative processes. We argue that early
olfactory relays are active and dynamical networks, whose actions change the format of odor …