Effects of REM sleep manipulations on spatial learning in the rat.

Abstract

Many early studies using REM sleep or total sleep deprivation showed deficits in learning and memory in humans and other animals. While many experimenters have used REM sleep deprivation to decrease REM sleep resulting in impaired learning, few have attempted to increase REM sleep to facilitate learning. If REM sleep is actively and positively involved in learning and memory processes, then increasing REM sleep or some parameter within REM sleep may facilitate those learning and memory processes. The work in this dissertation describes experiments in which REM sleep deprivation and auditory stimulation were used to determine their respective effects on learning. REM sleep deprivation resulted in slower learning, and while REM sleep deprived animals were able to reach the same level of performance as cage sleeping controls within the 15-day testing period, they continued to rely on less-efficient strategies to solve the task. Auditory stimulation did not consistently increase REM sleep nor did it alter learning on its own; however, auditory stimulation following REM sleep deprivation rescued the learning deficits caused by REM sleep deprivation in the absence of any obvious change to REM sleep. The results of these experiments support the overall hypothesis that REM sleep is important for learning and underscore the importance of distinguishing between strategies used within a learning study. Furthermore, the ability of auditory stimulation to rescue REM sleep deprivation-induced learning deficits in the absence of any obvious change to REM sleep parameters demonstrates the complexity of the role of REM sleep in learning.