I support Pylyshyn's skepticism that visual imagery reflects a re-activation of the spatial layout of active neurons embedded within a topographical cortical map of visual space. The pickup of visual information via successive eye movements presents one problem and the two visual systems model poses another difficulty.
The two modes of visual processing “localizing” versus “identifying” as expressed by four authors in 1967 are more encompassing than the “two visual systems” dichotomies posed by later theorists. Norman's view of parietal cortex functions of vision seems much too narrow.
Collerton et al. postulate that in a variety of different clinical conditions, hallucinations are derived from object schema lodged in long-term memory. I review two new experiments in which memory images can be easily triggered in neurologically intact subjects. These examples of making visible items in memory may provide experimental models for genesis of hallucinations.