Spatial Navigation and Dementia

The sense of place and the ability to navigate it are primary brain functions.^1,2 We depend on these spatial functions to find our way around our environment.^1,2 Edward Tolman (1886–1959), an American psychologist, proposed that animals could experience relationships between places and events and that the exploration of the environment gradually resulted in the formation of a cognitive map that enabled animals (and humans) to navigate through their environment.³ Two broad navigational strategies have been identified: egocentric and allocentric.¹ Egocentric (self-centered) navigation proceeds from the viewpoint of the navigator and is typically used when navigating a familiar route.^1,2 Allocentric (map-based) navigation depends on the navigator's perception of landmark positions relative to other landmarks and is typically used when navigating a novel environment.² Egocentric and allocentric navigation usually work together but can also be dissociated from each other.² The hippocampus and medial temporal lobe is more strongly associated with allocentric navigation, whereas the precuneus and caudate are more important for egocentric navigation.^2,4 Spatial navigation in general, however, is a complex multimodal process that involves a large network of cortical and subcortical brain regions—including the medial temporal lobe, entorhinal cortex, parahippocampal gyrus, retrosplenial cortex, parietal lobe, and the prefrontal cortex.^2,4,5