RIDDOCH'S PHENOMENON

Also known asRiddoch syndromeandstatico-kinetic dissociation. Both terms are used to denote a "blindness to stationary light stimuli, combined with an unaffected conscious perception of moving light stimuli. Riddoch's phenomenon is associated with "cerebral amblyopia, a disorder of visual perception due to retrochi-asmal lesions to the visual system which spare area V5, the specialized motion area ofthe visual cortex. The condition is named after the Scottish neurologist George Riddoch (1888-1947), who was the first to describe it in 1917, on the basis of observations of soldiers returning from World War I with gunshot wounds affecting the calcarine cortex. On the basis of those same observations, Riddoch suggests that movement constitutes a special aspect ofvisual perception, to be distinguished from the perception of light, form, and colour. Conceptually, Riddoch's phenomenon constitutes the counterpart of "akinetopsia (i.e. the inability to see motion).

Riddoch, G. (1917). Dissociation of visual perceptions due to occipital injuries, with especial reference to appreciation of movement.Brain, 40, 15-57.

Zeki, S., ffytche, D.H. (1998). The Riddoch syndrome: Insights into the neurobiology of conscious vision.Brain, 121, 25-45.