Rearing condition affects the development of allocentric responding and hippocampal n-methyl-d-aspartate receptors in rats

Rats were reared in one of two conditions; RESTRICTED and OPEN. Rats reared in the RESTRICTED condition were reared without access to stable patterns of visual landmarks and rats reared in the OPEN condition had access to such landmarks. The rats reared in the RESTRICTED condition did not exhibit allocentric spatial behavior when tested at age 52 days using a 4-trial habituation paradigm while rats in the OPEN condition did respond allocentrically. Further, the rats reared in the RESTRICTED condition failed to respond allocentrically during a second day of testing when the test required them to use landmarks on the floor rather than on the walls of the arena. However, the RESTRICTED rats did respond egocentrically when tested a third time, indicating that their failure to respond allocentrically during the first two tests was probably not due to a general inability to notice changes in object location. Hippocampi of rats reared in the RESTRICTED and OPEN conditions were examined using [3H] TCP kinetic binding analysis to determine if the rats differed in number or response of NMDA receptors