control group to have them learn to navigate a 3D maze. The blood flow in the parahippocampal gyrus increased in conjunction with the individual's performance through the 3D maze. Participants were then trained in the maze for 4 hours and later, during the various sleep cycles of NREM 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/NREM 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. One theory suggests a model of hippocampal-neocortical dialogue. "Two stages of hippocampal activity have been proposed, the first being the recording of the memory during waking and the second involving the playback of the memory during NREM sleep. This process of reactivation of memory firing sequences is believed to gradually reinforce initially weak connections between neocortical sites allowing the original information to be activated in the cortex independently of the hippocampus, and thus ensuring refreshed encoding capacity of the hippocampus." Maquet concluded that the areas of the brain involved with information processing and memory have increased brain activity during the slow wave sleep period. Events experienced in the previous day have more efficient and clearer memory recall the next day thus indicating that the memory regions of the brain are activated during SWS/NREM sleep instead of being dormant as previously thought. NREM SWS, also known as slow wave activity (SWA), is regarded as highly important in brain development due not only to its homeostatic behavior but also because of its distinct correlation with age. Children sleep longer and deeper than adults. The difference in depth of sleep has been quantified by EEG recordings of SWA. An increase in SWA peaks just before puberty and exponentially decreases from adolescence to adulthood in both longitudinal and cross-sectional studies of typically developing participants. This phenomenon is understood as memories and learned skills being metabolized during NREM sleep; the decrease in SWA is considered a reflection of synaptic rewiring and, therefore, an effect of behavioral maturation concluding. The critical period from childhood to emerging adulthood is also considered a sensitive period for mental disorders to manifest. For