One-dimensional "ring" in anterodorsal thalamic nucleus represents head direction
“The intrinsic attractor manifold and population dynamics of a canonical cognitive circuit across waking and sleep”](
(closed access)

“There are no degree markings in the external world; our current head direction has to be extracted, computed, and estimated by the brain,” explains Ila Fiete, an associate member of the McGovern Institute and senior author of the paper. “The approaches we used allowed us to demonstrate the emergence of a low-dimensional concept, essentially an abstract compass in the brain.”

This abstract compass, according to the researchers, is a one-dimensional ring that represents the current direction of the head relative to the external world.