Various types of cells have been identified in rodent studies to code spatial information relevant for navigation, such as the head direction cells in the Thalamus, place cells in the hippocampus, and grid cells in the entorhinal cortex. Recently, a vector coding scheme has also been observed in rodents (Deshmukh and Knierim, 2013) as well as in humans (Kunz et al., 2021), where activities of sub-populations of cells are modulated by either non-extending landmark or boundaries at a certain distance and direction from the navigator. In this study, we examine such vector coding in healthy young adults with fMRI. Participants memorized four target locations in relation to a fixed landmark in a virtual environment, with the landmark providing both directional and distance information. Representational similarity analysis (RSA) reveals that various regions within the navigational network (e.g, the precuneus) as well as the visual-processing areas track participants’ locations relative to the landmark. In addition, multivoxel pattern responses in the retrosplenial cortex and the lateral occipital area reflect the Euclidean distance information between targets.

Reference:
Deshmukh SS, Knierim JJ. Influence of local objects on hippocampal representations: Landmark vectors and memory. Hippocampus. 2013 Apr;23(4):253-67.
Kunz L, et al. A neural code for egocentric spatial maps in the human medial temporal lobe. Neuron. 2021 Sep 1;109(17):2781-2796.e10