The neural basis of Charles Bonnet hallucinations: a hypothesis
- Departments of Physiology, Anatomy and Histology and Institute for Biomedical Research, University of Sydney, Sydney, Australia
- Correspondence to: Professor W Burke, Department of Physiology (F13), University of Sydney, NSW 2006, Australia;
- Received 28 February 2002
- Accepted 3 July 2002
- Revised 24 June 2002
Objectives: To describe the hallucinations occurring as a result of a macular hole in each eye and to investigate the neural basis.
Methods: Psychophysical observations including sketches of the hallucinations calibrated for size.
Results: All the hallucinations were of the geometric (patterned) type and lasted for only a few days.
Conclusions: The observations can be explained on the basis of a “deafferentation” model, which is described in some detail. It is proposed that the hallucinations result from activation of the “blobs” of area V1 and the “stripes” of area V2 in the visual cortex. A theory is proposed to account for the disappearance of the hallucinations by a “filling in” mechanism.
Competing interests: none declared
See editorial commentary, page 472