A 76-year-old woman presented with catatonia, refusal to eat due to delusion, and visual hallucination. Single photon emission computed tomography showed remarkable occipital hypoperfusion and frontal hyperperfusion. (123)I metaiodobenzyl guanidine myocardial scintigraphy revealed decreased uptake. She was diagnosed as probable dementia with Lewy bodies (DLB). Intravenous or oral L-dopa had no ...

The "psychic tonus" model or PTM [1] of hemispheric specialization states that the left hemisphere is a psychic and behavioral activator and that the right hemisphere is an inhibitor. The PTM predicts that the tonus of visual representation ought to manifest hemispheric specialization in the occipital lobes. Specifically PTM predicts that pathological positive visual tonus (visual hallucination...

The pathogenesis of complex visual hallucination by suppression of inhibitory cortical input to visual association areas is considered as the “release phenomenon”. A 79 year-old man without dementia or hallucinations history experienced complex visual hallucinations in the right lower quadrantanopia area after traumatic subdural hematoma (SDH) of the left occipital region. The vivid hallucinati...

Hallucinations occur in both normal and clinical populations. Due to their unpredictability and complexity, the mechanisms underlying hallucinations remain largely untested. Here we show that visual hallucinations can be induced in the normal population by visual flicker, limited to an annulus that constricts content complexity to simple moving grey blobs, allowing objective mechanistic investi...