Performance deficits in a water maze: Effect of REM sleep deprivation or cold stress?

The current study aims to determine the relation between memory consolidation and rapid eye movement (REM) sleep by measuring performance deficits in a behavioral task after periods of sleep deprivation. As in many prior studies, REM sleep deprivation is to be arranged by placing rats on a small platform surrounded by water. This relatively simple procedure for inducing REM sleep deprivation has been described previously as the "flower pot" technique. By using this technique, rats entering sleep lose muscle tone and fall into the water thereby preventing REM sleep. However, since no previous attempts have been made to heat the water used in the flower pot technique, animals have necessarily been exposed to cold stress as well as sleep deprivation. Therefore, a second goal of this work is to examine whether any previously observed deficits on spatial memory tasks are truly the result of REM sleep deprivation instead of the product of cold stress induced during prolonged exposures to the cool water used in the sleep deprivation apparatus.