Spatial navigation is supported by the combined activity of brain regions in the human navigation network (HNN) that integrates environmental information across complementary egocentric and allocentric reference frames. Despite humans mainly relying on vision to navigate space, the impact of early visual deprivation on the HNN is mostly unknown. In our experiment sighted and early blind participants were tested in two tasks of imagined navigation while undergoing fMRI. Results show, on the one hand, that both sighted and blind activated regions of the HNN during navigation, with no differences between groups. On the other hand, quadrature filter analysis in the entorhinal cortex, a crucial region for the creation of cognitive maps, revealed an alteration of grid-like coding in early blind individuals, which might be correlated to the adoption of egocentric-like strategies to navigate in space.

How do humans compute approximate number? According to one influential theory, approximate number representationsarise in the intraparietal sulcus and are amodal (independent of any sensory modality). Alternatively, approximate numbermay be computed initially within sensory systems. We tested for approximate number representations in the visual systemusing steady state visual evoked potentials (SSVEPs). We recorded EEG from human subjects while they viewed dotcloudspresented at 30 Hz. Alternating the dotcloud numerosity at 15 Hz evoked a 15 Hz SSVEP detectable over the occipital lobe(Oz). The SSVEP amplitude increased as the numerical difference between dotclouds increased, indicating that subjectsvisual systems were differentiating dotclouds on the basis of their numerical ratios. Critically, subjects were unable toconsciously discriminate dotcloud numerosity, indicating the rapid presentation disrupted reentrant feedback to visualcortex. Approximate number appears to be computed within the visual system, independently of higher-order areas suchas the intraparietal sulcus.

Throughout the lifespan and across cultures, all human behavior happens in space. By early childhood, people are capable of navigating complex 3D environments, executing sophisticated motor plans, and coordinating action with others. They also use their representations of space to structure a variety of non-spatial concepts, including time, number, similarity, and emotion. How do people perform these cognitive feats? One source of insight comes from studying the diversity of spatial cognition: Although the physical properties of space are invariant, the way people typically conceptualize space varies radically across groups, between individuals, and over development. By studying this variation in spatial cognition, we can better understand the universal set of cognitive and neural mechanisms that underlie it, with implications for the cognitive sciences, education, and design.