| Abstract: | This study tested the hypothesis that environmental rearing treatments which alter the REM sleep levels of rats affect swimming immobility, an adaptive, REM sleep sensitive behavior. At weaning, 72 female Sprague-Dawley rats were maintained in either an enriched, an impoverished, or a social control environment for 32–33 days. They were then placed in either a REM sleep depriving platform-in-water condition or in one of two control conditions (large platform or dry control) for 4 days before being scored for swimming immobility during a 10-min swimming test. A 3 (environments) × 3 (platforms) ANOVA revealed a main effect for environments, F(2,63)=5.20, p<0.01. Enriched rats exhibited a behavioral advantage over impoverished rats under the large platform control condition, F(1,63)=6.58, p<0.025, and under the dry control condition, F(1,63)=6.14, p<0.025. However, under the REM depriving condition, their behavioral advantage was virtually eliminated, F(1,63), p<1. The conclusion that the REM sleep levels of the rat groups probably determined their swimming immobility scores is discussed. |
