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K. S. LASHLEY 



occipital cortex, which lies in the lateral margin of field w 

 of Fortuyn. Figure 1 shows the areas common to cerebral 

 lesions which completely abolished the capacity for pattern 

 vision. The area essential for pattern vision seems quite 

 constant from animal to animal. Only one case has shown 



Fig. 1 Visual areas of the cerebral cortex of the rat. The stippled areas 

 represent the regions destroyed by operations, symmetrical on the two hemi- 

 spheres, without disturbance of the capacity for pattern vision. The coarser 

 stippling indicates the position of the anatomical area striata. Destruction of 

 the cortex at b or c on both hemispheres completely abolishes vision for patterns, 

 but leaves the capacity to distinguish the position and relative brightness of 

 gross objects, as does the total destruction of the visual cortex. Interruption 

 of the projection fibers at a abolishes all vision for objects, but leaves the 

 capacity to distinguish differences in the intensity of light. 



any evidence of discrimination of patterns after destruction 

 of this area, and in no case in which the area escaped de- 

 struction in both hemispheres was there any reduction in 

 discrimination of patterns, even though the lesions extended 

 to the margins of the area. Cortical destruction limited to 

 this area is sufficient to abolish all detail vision. 



