Flexible navigational computations in the Drosophila central complex

Abstract

Insects can perform impressive feats of navigation, suggesting a sophisticated sense of direction and an ability to choose appropriate trajectories toward ethological goals. The hypothesized substrate for these navigational abilities is the central complex (CX), a midline brain structure with orderly topology. The circuit transformations performed by the CX are now being concretely described by recent advances in the study of fruit fly neural circuits. An emerging theme is dynamic representation of navigational variables (e.g. heading or travel direction) computed in a manner distributed across specific neuronal populations. These representations are shaped by multimodal inputs whose weights evolve rapidly as surroundings change. Investigation of CX circuits is revealing with precise detail how structured wiring and synaptic plasticity enable neural circuits to flexibly subsample from the currently available sensory and motor cues to build a stable and accurate map of space. Given the sensory richness of natural environments, these findings are encouraging insect neuroscientists to no longer ask which cues insects use to navigate, but instead which cues can insects use, and under which contexts.