The advent of functional neuroimaging techniques, including positron emission tomography (PET) and functional nuclear magnetic resonance imaging (fMRI), has opened up a new vista into the nature of brain functions underlying sensory and higher mental processes, including vision, visual imagery, creative planning and ideation.
Recent functional imaging studies have fuelled a new debate on the similarity or dissimilarity of the neuronal operations engaged by visual processes as opposed to visual imagery processes. On the basis of their experimental findings, some claim that visual perception and visual imagery occupy identical neuronal machineries in the human brain. Others, including the present author and his colleagues, claim that there is only a partial overlap between the neuronal populations engaged by sensory visual information processing and the generation and elaboration of visual imagery information in the human brain.
The more, there is an increasing body of evidence that visual imagery processes use the same mental strategies and occupy identical neuronal populations as a number of other higher mental processes, including ideation, day-dreaming, “fantasising”, creative planning in visual arts and, most probably, the apperception of apparitions, let them be of religious or other types.
On the basis of scanty and rather preliminary experimental and observational data, the author would like to propose a hypothesis, raise questions about the neurobiological basis of creative visual imagery and imagination, and beg the audience for alternative explanations, novel conjectures or evidence- based refutations.