Categorical and coordinate spatial representations within object-location memory

An important aspect of spatial memory is the ability to remember the positions of objects around us. There is evidence that spatial information can be represented in different ways, involving a coordinate representation (fine-grained, metric information) and a categorical representation (above/below, right/left relations). The current study is aimed at investigating possible lateralization effects for categorical and coordinate information when encoding position information alone and when integrating position information and object information in memory. Twenty-five patients who had suffered from a stroke and 36 healthy controls were tested with different tests assessing categorical and coordinate position memory, and categorical and coordinate object-to-position memory. The identity task that was used by (Laeng, 1994) was included as well as a control task for measuring lateralization effect for categorical and coordinate information. Moreover, object-recognition and visuo-spatial perception were assessed. The results showed that processing categorical and coordinate spatial information were impaired by a lesion in the left and right hemisphere, respectively. No lateralization effects were found when spatial information had to be integrated with object information. These results bear on the functional components of object-location memory and their underlying hemispheric basis.