Visual motion and landmark position align with heading direction in the zebrafish interpeduncular nucleus

Sensory information is fundamental for navigation. Visual motion is used by animals to estimate their traveling distance and direction, and landmarks allow animals to tether their location and orientation to their environment. How such signals are integrated in the vertebrate brain is poorly understood. Here we investigate the representation of directional whole field visual motion and landmark position in the larval zebrafish head direction circuit. Using calcium imaging we show that these stimuli are represented in the habenula, interpeduncular nucleus and anterior hindbrain. In the dorsal interpeduncular nucleus, both stimuli are topographically arranged and align with the representation of the heading signal. Neuronal ablations show that the landmark responses, but not the whole field motion responses, require intact habenula input. Our findings suggest the interpeduncular nucleus as a site for integration of the heading signal with visual information, shedding light on how navigational signals are processed in the vertebrate brain.