Table 1.

List of diseases, nature of visual hallucinations, and possible neuronal orders affected.

Location	Nature of hallucinations	Neuronal order
Retina and choroid (Siatkowski et al., 1990; Holroyd et al., 1992)	Flickering flashes of light	1
Vitreal detachment (Schmidt et al., 1996)	Brief vertical flashes of light	1
Optic neuritis (Davis et al., 1976)	Spontaneous flashes of light	1
Occipital epilepsy (Panayiotopoulos, 1994)	Brief, stereotyped, fragmentary, and multi-colored lines of simple patterns	∼2–5
Occipito-temporal ictal (Young et al., 1989)	Palinopsia (image recurs immediately after gaze diversion)	∼3–6
Fusiform gyrus activation (Cardoso et al., 2010)	Hallucinations in color	∼3–6
Focal seizures of temporal lobe (Bancaud et al., 1994)	Deja vu, jamais vu	∼4–8
Diffuse Lewy body disease (O’Brien et al., 2005)	Vivid visual hallucinations: colorful and complex involving scenes of people and animals	Many?
Schizophrenia (David et al., 2011)	Convincing sense of reality with lack of stereotypy (contents vary)	Many?

It is observed that the higher the neuronal orders at which lateral entry of activity occurs, the more well-formed, non-stereotypical, and convincing are the hallucinations produced.