Learning and representing the spatial properties of objects via tactile exploration

AbstractNeural representations of physical space must be learned through physical exploration, especially with regard to the visual appearance of three dimensional structure. Moreover, neural activity is known to respond to the spatial extents of solid objects in the similar ways as though they were environments unto themselves. Information about environments such as identified in mammalian place and grid cells are considered to represent space in allocentric coordinates, despite the experience of the animal itself as inherently egocentric. There is also evidence for object-centred representations of the spatial properties of objects. This analogy between the frames of the spatial environments in which we move and the spatial extents of objects, raises the possibility of a second egocentric reference frame which the observer projects into object-centered-spaces, which we propose to be defined by coordinates of the visual field or centered on an observer's hand, or limb. Adapting a dead-reckoning model of place field development, we show that the exploration of physical objects by touch can naturally lead to the formation of place field-like representations in object-centered space. Our proposal offers the tantalising possibility of completing a duality in the representation of objects and spaces, which forms a powerful basis on which to represent three-dimensional space.