Representation of nearby and infinitely far reference frames in the brain

While navigating the world, our brain needs to keep track of the space around us. A brain region called the Hippocampus plays a significant role in our perception of space. Our work shows that hippocampal cells recognize space as a vector! Hippocampal Place Cells have been shown to keep track of the subject's absolute position. Using GLM, we show that hippocampal cells also keep track of the direction of the rat's position with respect to various frames of reference. These frames include infinitely far frames, thus keeping track of the canonical Head Direction[1]. We also show that these cells utilize various frames of reference at finite distances from the rat's current position. We call the origin of these reference frames as Anchor Points. We see that these cells code for such anchor points in coherent and stable ways, and we call such tuning of these cells as Anchor Fields. We observe that visual cues are capable of affecting various properties of these anchor tunings, including position of Anchor Points, size of Anchor Fields, percentage of cells tuned, and the direction of tuning with respect to these anchor points. We posit that hippocampal cells utilize these tunings to create a vectorial map of space in our brains.
[1] Acharya et al. Cell 164.1-2 (2016): 197-207.