Transformations of visuospatial images.

Transformations of visuospatial mental images are important for action, navigation, and reasoning. They depend on representations in multiple spatial reference frames, implemented in the posterior parietal cortex and other brain regions. The multiple systems framework proposes that different transformations can be distinguished in terms of which spatial reference frame is updated. In an object-based transformation, the reference frame of an object moves relative to those of the observer and the environment. In a perspective transformation, the observer's egocentric reference frame moves relative to those of the environment and of salient objects. These two types of spatial reference frame updating rely on distinct neural processing resources in the parietal, occipital, and temporal cortex. They are characterized by different behavioral patterns and unique individual differences. Both object-based transformations and perspective transformations interact with posterior frontal cortical regions subserving the simulation of body movements. These interactions indicate that multiple systems coordinate to support everyday spatial problem solving.