Background: The presence of visual imagery in dreams of congenitally blind people has long been a matter of substantial controversy. We set to systematically review body of published work on the presence and nature of oneiric visuo-spatial impressions in congenitally and early blind subjects across different areas of research, from experimental psychology, functional neuroimaging, sensory substitution, and sleep research.
Methods: Relevant studies were identified using the following databases: EMBASE, MEDLINE and PsychINFO.
Results: Studies using diverse imaging techniques and sensory substitution devices broadly suggest that the "blind" occipital cortex may be able to integrate non-visual sensory inputs, and thus possibly also generate visuo-spatial impressions. Visual impressions have also been reported by blind subjects who had near-death or out-of-body experiences.
Conclusion: Deciphering the mechanistic nature of these visual impression could open new possibility in utilization of neuroplasticity and its potential role for treatment of neurodisability.
Keywords: congenitally blind; cross-modal plasticity; dreams; metamodal brain; visuo-spatial imagery.
Copyright © 2023 Ilic, Bertani, Lapteva, Drakatos, Delogu, Raheel, Soteriou, Mutti, Steier, Carmichael, Goadsby, Ockelford and Rosenzweig.