1/28/2004   slide 12
Components of Vision Processing Revealed by Brain Injuries
•Man who, after brain damage from carbon monoxide poisoning, could not see/make sense of objects, despite no problem with visual acuity or seeing motion, etc. [Hoffman 1998] p47
•Woman with dorsal simultanagnosia: can see parts but not assemble large group of them into a scene or even simple parts into one object. Saw pitcher, handle—said maybe suitcase? [Hoffman 1998] p79
•Woman who could see “fine” but could not see motion: liquid pouring looked frozen, cars appeared suddenly (this state can be induced by magnetically (temporarily) impairing certain area of visual cortex). [Hoffman 1998] p139
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On left: visible part of primary visual cortex.
http://neuro.med.harvard.edu/site/dh/b14.htm#topo
Role of these bizarre stories: to show how “vision” is many processes in the brain, with whole objects/motion arising from separating processing of form, color, motion, parts, and wholes…With advanced medical imaging and other techniques, vision science has taken off in the last 25 years and much new research has been done.

Still a great deal that we do not know, however.