Non-rapid eye movement sleep 3D maze. Participants were then trained in the maze for 4 hours and later, during the various sleep cycles of nonREM sleep, REM sleep and wakefulness, they were scanned twelve times using a PET scan during the night. The PET scan demonstrated a higher blood flow in the hippocampus during SWS/non-REM sleep due to the training from the previous day while the control group exhibited no increased blood flow and they had not received the training the prior day. The brain activity during sleep, according to this study, would show the events of the previous day do make a difference.
Rapid eye movement sleep laboratory animal above water on a platform so small that it falls off upon losing muscle tone. The naturally rude awakening which results may elicit changes in the organism which necessarily exceed the simple absence of a sleep phase. This method also stops working after about 3 days as the subjects (typically rats) lose their will to avoid the water. Another method involves computer monitoring of brain waves, complete with automatic mechanized shaking of the cage when the test animal drifts into REM sleep. Some researchers argue that the perpetuation of a complex brain process such as REM sleep indicates