Axial encoding schematics of neural representations of 3D space in freely navigating goldfish

Navigation is one of the most fundamental cognitive skills for the survival of fish, the largest vertebrate class, and almost all other animal classes. A critical component of the neural basis of navigation is the encoding of space in the activity of single neurons. To study this basic cognitive component in fish, we recorded the activity of single neurons in the central area of the goldfish telencephalon while the fish were freely navigating in a 3D water tank. We found neurons with firing patterns that gradually increased or decreased along spatial axes distributed in all directions. Some of these cells exhibited beta rhythm oscillations. This type of axial coding for spatial representation in the brains of fish is unique among space encoding cells in vertebrates and provides insights into spatial cognition in this lineage. ### Competing Interest Statement The authors have declared no competing interest.