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Although new evidence from brain-imaging studies is constantly emerging, the basic aspects of anatomical and physiological knowledge of the primate visual system have been know for some time, and are covered in many texts such as Frisby (1979).

The image on the retina first reaches the cortex in “V1” (or “striate cortex”, or “primary visual cortex”) in the occipital lobe. There is a regular “retinotopic” mapping of points on the retina to points on V1 [illustration 1 from Frisby, 1979; illustration with scale]

Physiological studies performed by recording from electrodes inserted in the brains of monkeys and cats while a variety of visual stimuli are projected on to the retina establish the characteristics of the “receptive fields” of individual cells.

Examples are figure 11.2 (page 91) and figure 11.3 (page 92) and also figure 14. 3 (page 127) in Zeki (1993), the main reference. These physiological studies provided evidence for the distinction between several different areas of secondary visual cortex, the first ones usually labelled V2, V3, V4 and V5. A summary of these neuroanatomical distinctions was given on page 15 of the paper handout. 

Two large 'Shockwave Flash' files, at the University of Western Ontario, display the neuroanatomy and physiology of primary and secondary visual cortex in considerable detail.

wwwgif Direct link to swf file on primary visual cortex | open primary file in new window.

wwwgif Direct link to swf file on secondary visual cortex | open secondary file in new window.  


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