The representation of visual motion and landmark position aligns with heading direction in the zebrafish interpeduncular nucleus
https://www.biorxiv.org/content/10.1101/2024.09.25.614953v1
Briefly – we show that different visual signals that are important for navigation are aligned with the heading signal in a specific region in the zebrafish brain.
Most animals use visual information to navigate. Visual motion helps animals to estimate their traveling direction and visual landmarks allow animals to tether their location and orientation to their environment. But how are such signals integrated in the vertebrate brain?
We wanted to investigate how visual cues that are important for navigation are represented in the habenula – interpeduncular nucleus (IPN) – anterior hindbrain (aHB), a circuit recently implicated in head direction representation.
We imaged the fish brain while presenting it with two types of visual signals: directional whole field motion and a light bar that could be used as a landmark.
We found that directionally-selective responses within the IPN are not only topographically organized, but are also aligned with the representation of the heading signal in this region.
We show that the habenula, a major source of input to the IPN, contains neurons responding to directional visual motion and neurons responding to landmark position. Using ablations we tested whether the visual responses at the IPN depend on habenular input.
This doesn’t seem to be the case for directional motion representations, yet habenula input is necessary for landmark representations in the IPN.