Maintaining a visual image impairs a contrasting visual perception, but facilitates an identical visual perception.
Imagery can induce perceptual illusions.
Brain scans suggest that the same areas are used for both imaging and visual perception. Patients with unilateral visual neglect often had a corresponding lack of half a mental image. Kosslyn himself believes that not only are images produced by the same processes that are responsible for visual perception, but that effective visual processing is dependent on the imaging process. These are used in both perception and imagery. If a single representation is not produced, a search is started for the best match.