The neural basis of mental imagery.

Visual mental imagery, or 'seeing with the mind's eye', has been the subject of considerable controversy in cognitive science. At issue is whether images are fundamentally different from verbal thoughts, whether they share underlying mechanisms with visual perception, and whether information in images is represented in a spatial (i.e. map-like) format. Research on the neural systems underlying imagery brings a new source of evidence to bear on these cognitive science controversies, as well as on the cerebral localization of imagery processes. Emerging from this work is the view that mental imagery involves the efferent activation of visual areas in prestriate occipital cortex, parietal and temporal cortex, and that these areas represent the same kinds of specialized visual information in imagery as they do in perception. In addition, different components of imagery processing appear to be differentially lateralized, with the generation of mental images from memory depending primarily upon structures in the posterior left hemisphere, and the rotation of mental images depending primarily upon structures in the posterior right hemisphere.