The Japanese journal of neuropsychology

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ArticleTitle	Visual disorders after brain injury
Language	J
AuthorList	Kazumi Hirayama
Affiliation	Department of Behavioral Neurology and Cognitive Neuroscience, Tohoku University Graduate School of Medicine
Publication	Japanese Journal of Neuropsychology: 24 (3), 198-210, 2008
Received
Accepted
Abstract	Converging evidence indicates that there are four axes in the streams of visual information processing in man: 1) left and right, in that the left hemisphere is opted for processing verbally coded information, while the right hemisphere deals with non-verbal information; 2) dorsal and ventral streams with the former being directed to the parietal lobe for processing object location and movement to form conscious representation of objects, and the latter directed to the temporal lobe for processing shape and color of the objects to identify them and to retrieve the knowledge of them; 3) lateral and medial sectors with the latter involving evolutionally older functions, while lateral sector is for newly evolved functions; 4) rostral, and caudal sections, of which caudal section includes regions in which retinotopy is preserved and those where visual information is processed independent of its retinal location, while rostral section contains multimodal area that functions to integrate information derived from multiple sensory channels. Responsible cites for various visual impaiments like cerebral achromatipsia, akinetopsia, visual agnosia, visual inattention, hemispatial neglect, loss of semantic memory, loss of visual imagery, visual hallucination and illusion are discussed with reference to these four axes.
Keywords	dorsal stream, ventral stream, form, visual image, illusion