INTRINSIC AND ENVIRONMENTAL-FACTORS IN THE DEVELOPMENT OF FUNCTIONAL MAPS IN CAT VISUAL-CORTEX

In the mammalian visual cortex, key neuronal response properties such as orientation preference and ocular dominance (OD) are mapped in an o rderly fashion across the cortical surface. It has been known for some time that manipulating early postnatal visual experience can change t he appearance of the OD map. Similar evidence for developmental plasti city of the orientation map has been scarce. We employed optical imagi ng of intrinsic signals to examine the contribution of intrinsic and e nvironmental factors to the development of cortical maps, using the pa radigms of strabismus, reverse occlusion and rearing in a single-orien tation environment ('stripe-rearing'). For several weeks after inducti on of strabismus, the pattern of OD domains remained stable in young k ittens. The isotropic magnification of the OD map matched the postnata l growth of the Visual cortical surface during the same period. In rev erse-occluded and in stripe-reared kittens, orientation preference map s obtained through the left and the right eye were very similar, altho ugh the two eyes had never shared any visual experience. We suggest th at the geometry of functional maps in the visual cortex is intrinsical ly determined, while the relative strength of representation of differ ent response properties can be modified through visual experience. (C) 1998 Elsevier Science Ltd. All rights reserved.