The role of pattern vision in the increase of visual cortex acetylcholinesterase after first exposure of dark reared rats to light.

Acetylcholinesterase (AChE) activity in homogenates from motor and visual cortex of rats reared for 7 weeks in darkness was compared to levels in normally reared and dark reared littermates exposed to 3-h periods of controlled illumination. AChE levels in the visual cortex of animals fitted with light-diffusing scleral contact occluders, and therefore lacking normally organized visual information, were elevated 17% over dark-reared animals, but were not significantly different from levels in animals exposed to lighting conditions permitting detailed pattern discrimination. There were no differences between conditions in motor cortex AChE. We conclude that higher order perceptual processing is not necessary for the light-stimulated increase in visual cortex AChE in the rat.