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Hallucinations Associated with Brain Hyperactivity in People with Age-Related Blindness

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New research from The University of Queensland has revealed that visual hallucinations in people with macular degeneration are associated with abnormally heightened activity in the visual cortex of the brain. The findings, published in Current Biology (, could improve the diagnosis of such hallucinations.

Macular degeneration is a retinal eye disease that causes progressive deterioration of the central region of the retina, leading to visual loss in the centre of the field of vision while peripheral vision usually remains unaffected. Many people who develop macular degeneration also develop Charles Bonnet Syndrome, in which they experience hallucinations as the brain adjusts to significant vision loss. The hallucinations can be simple geometric patterns, or much more complex scenes involving animals, people and places.

Why some people with macular degeneration experience hallucinations while others do not has remained unclear, but there have been suggestions that the excitability of some visual regions of the brain could play a role. To address this, the research team measured brain electrical activity while stimulating the peripheral visual fields of study participants.

“Their task was to look at letters appearing on the screen in their periphery, and we flashed...

The full text of this article can be purchased from Informit.