The relation between cardinal axes, spatial cells and navigation performance

Obtaining unbiased spatial information is a prerequisite for accurate spatial orientation, navigation, and spatial memory. Common sources for obtaining such spatial information are 2D maps and 3D visualizations of space. However, the exact way external spatial representations are integrated into a cognitive map is still not fully understood. Currently, there is much research on the cells forming the spatial map in the hippocampal and parahippocampal cortices. In interaction with other cell types, grid cells appear to play a dominant role in the formation of the cognitive spatial map. Grid cells are characterized by repeated firing fields arranged in a sixfold rotational symmetry. Using a path integration task, we investigated whether artificial spatial elements mirroring the sixfold rotational symmetry can improve navigation performance. This would be an indication that grid cells respond to these artificial elements. In the reported study, we investigated the influence of artificial cardinal axes arranged with 60° (matched to grid cell symmetry) and 30° (mismatched to grid cell symmetry) angles in a reduced 3D spatial environment. Although, the results are not conclusive, they do indicate a trend that participants benefit from a 60° angle in trials with moderate difficulty. Thus, we found the first evidence that mirroring their sixfold rotational symmetry with artificial cardinal axes may trigger grid cells. Future studies should investigate this connection in more detail and a virtual 3D environment shown by head-mounted displays. This might lead to a more detailed insight into the neuropsychological mechanisms underlying the transfer from maps and 3D environments in the cognitive map and how this can be optimized.