Visual and mental exploration of visuo-spatial configurations: behavioral and neuroimaging approaches.

Do mental imagery and perception involve common processing mechanisms? Imagery researchers have devoted a great deal of effort to establishing the functional and structural similarities between images and perceptual events. Recent studies have focused on the comparison of images that are reconstructions of previous perceptual experience and images constructed from verbal descriptions. This article reports the findings of a research program based on the mental scanning paradigm; they reveal the similarities and differences between the two kinds of mental images. Neuroimaging studies have also provided evidence that the parieto-occipital cortex is involved in the processing of visual images, whether they are based on perceptual experience or constructed from linguistic inputs. However, the PET studies conducted by our research groups provide no evidence that the primary visual cortex is engaged in the generation of visual images. As there is contradictory evidence about this, further research is needed to clarify the role of the early visual areas in mental visual imagery.