Generation of stable heading representations in diverse visual scenes

Many animals rely on an internal heading representation when navigating in varied environments 1 – 10 . How this representation is linked to the sensory cues that define different surroundings is unclear. In the fly brain, heading is represented by ‘compass’ neurons that innervate a ring-shaped structure known as the ellipsoid body 3 , 11 , 12 . Each compass neuron receives inputs from ‘ring’ neurons that are selective for particular visual features 13 – 16 ; this combination provides an ideal substrate for the extraction of directional information from a visual scene. Here we combine two-photon calcium imaging and optogenetics in tethered flying flies with circuit modelling, and show how the correlated activity of compass and visual neurons drives plasticity 17 – 22 , which flexibly transforms two-dimensional visual cues into a stable heading representation. We also describe how this plasticity enables the fly to convert a partial heading representation, established from orienting within part of a novel setting, into a complete heading representation. Our results provide mechanistic insight into the memory-related computations that are essential for flexible navigation in varied surroundings. Two-photon calcium imaging and optogenetic experiments in tethered flying flies, combined with modelling, demonstrate how the correlation of compass and visual neurons underpins plasticity that enables the transformation of visual cues into stable heading representations.