Central processing in the mushroom bodies

•The mushroom bodies integrate and format sensory information.•Mushroom body information processing functions include gain control, response sparsening, decorrelation, and learning and memory.•The mushroom bodies assemble and format a representation of the insect's world.

The mushroom bodies in the insect brain serve as a central information processing area. Here, focusing mainly on olfaction, I discuss functionally related roles the mushroom bodies play in signal gain control, response sparsening, the separation of similar signals (decorrelation), and learning and memory. In sum, the mushroom bodies assemble and format a context-appropriate representation of the insect's world.