Three-dimensional Head Direction Cells in rodents
Here I show that head direction (HD) cells in mice encode a 3D neural compass. We recorded the responses of HD cells in the Anterior Thalamus, Cingulum fiber bundle and Retrosplenial Cortex of mice across the entire range of 3D head orientations. The 3D responses of HD cells can be decomposed into a 1D azimuth component that encodes head orientation in the horizontal plane, and a 2D pitch/roll component that encodes head orientation relative to vertical: the azimuth component is visually anchored, whereas the vertical component is anchored to gravity. I propose a conceptual framework of 3D orientation encoding in the HD system which is compatible with previous finding in bats, primates and rodents.
