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[page 7 of handout]
Some extracts from Zeki (1993) “A Vision of the Brain”
(This is given as reference, but substantive points made in this book do not differ from those in the Scientific American article: as the examples below show, the book is partly a history of controversies over cerebral localization of function, which are equally well covered in the Brain articles which are available online).


Chapter 4: Colour in the cerebral cortex (Also “Cerebral achromatopsia” pp265-278)

Mackay and Dunlop (1899) wrote that “the facts in this remarkable case, the first, as far as we know, in which a total acquired colour blindness from a cerebral lesion has been supported by pathological examination, point strongly towards the conclusion that if there is a separate centre for colour, its seat is the grey matter of the fusiform gyrus.”

Later on Zeki discusses other cases and says:

“The first important point to note about achromatopsia is that the retinal mechanisms mediating colour vision are intact in this condition... The fibres carrying the messages from the retina to the striate cortex are also intact. Hence the defect is entirely central, due to a specific lesion in the cerebral cortex. In brief, with achromatopsia, we witness a condition in which the signals relayed to the brain are normal but the mechanism used to construct colours is defective. (pp 267-8)

Mackay, G. and Dunlop, J.C. (1899) The cerebral lesions in a case of acquired colour-blindness. Scot. Med. Surg. J. 5, 503 -12.

Zeki, S. (1990) A century of cerebral achromatopsia. Brain, 113, 1721-1777. (available in the UCL Clinical Sciences Library, entrance on University Street or via the BK elibrary | log on first for access outside the College.)

 

Chapter 10, p 82 A motion-blind patient.

Zihl et al (1983) described a patient who had suffered a vascular disorder, which produced bilateral lesions outside the striate area. She had several problems including difficulties in calculations and mild aphasia. But her inability to see objects in motion was very striking. She had difficulty in pouring tea or coffee because the fluid appeared to be frozen, like a glacier. She complained of difficulties in following speech because she could not see the movements of the mouth of the speaker, and, when crossing the road, was only aware of cars in isolated individual positions, either near or far away.

 

Zihl, J., Cramon, D. von & Mai, N. (1983) Selective disturbance of movement vision after bilateral brain damage. Brain 106, 313-340 (BK elibrary: log on first for access outside the College.)

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

Zeki S. (1991) Cerebral akinotopsia (cerebral visual motion blindness) Brain, 114, 811-824. (BK elibrary: log on first for access outside the College.)

Holmes, G. (1918) Disturbance of vision by cerebral lesions. British Journal of Ophthalmology, 2, 353-384.

  


Start | basic neuroanat. | reading | zeki extracts | table of links | List of Refs | Journals