Many animals are able to record their position in the environment.
This kind of self-localization information can help achieve many important behaviors.
For example, the ability to return to a safe location after reaching an unknown and potentially dangerous area.
Although self-localization relies on hippocampal structures in the brain, the exact processes involved are not clear.
In a new study published in Cell, researchers reveal how larval zebrafish track their position and navigate after being pushed off course by ocean currents by exhaustively imaging and analyzing the entire brain at cellular resolution during behaviors that depend on self-localization.
By analyzing more than 100,000 neurons per zebrafish, the researchers revealed previously unknown brain regions associated with self-localization.
They identified a multi-regional hindbrain circuit that mediates the shift from speed to displacement memory to behavior.
When the animal actively or passively changes position, the underlying circuits form a memory of past displacements by integrating visual information and calculating localization in the dorsal brainstem.
The relevant data is read by the lower olive body as a persistent position error signal that reflects the difference between the original position of the fish and the current position.
Finally this signal is converted into an action output.
This multi-regional circuit may also interact with other known self-localization features, the researchers said.
