example, children with attention deficit hyperactivity disorder (ADHD), a brain disorder that affects cognitive and motor control, have shown considerably different cortical thickening trajectories in contrast with typically developing children per MRI data. Cortical thickness is a common measure of brain maturation; the main difference in children with ADHD shows a delay in cortical thickness, specifically in the frontal lobe. Significant correlations in the trajectory of gray matter thickness and SWA suggest that SWA may be able to indicate levels of cortical maturation on an individual level. However, there has yet to be a study in which the diagnosis of ADHD can be given directly from SWA readings. Memory Non-rapid eye movement sleep is known for its beneficial effect on memory consolidation, especially for declarative memory (while procedural memory improvement is more associated with REM-sleep), even if it is important to note that a clear-cut distinction between stages' influence on type of learning doesn't seem to be possible. Generally, both REM and NREM are associated with an increased memory performance, because newly encoded memories are reactivated and consolidated during sleep. NREM sleep has been demonstrated to be intimately correlated with declarative memory consolidation in various studies, where subject slept after a declarative memory-task; these who had a sleep imbued of NREM stages, had a better performance after the nap or the night, compared to subjects who have been awake or had more REM-sleep. The importance of NREM sleep in memory consolidation has also been demonstrated using cueing; in this paradigm, while participants are sleeping and are in NREM sleep stages, cues are proposed (which can be, for example, aurally-presented sounds or words, odors, and so on). The fact that this procedure was effective on the improvement of the later memory performance, indicates that during these stages, there is a reactivation of the memory traces and a subsequent consolidation, which are facilitated by the cues; importantly, this doesn't work if the cueing is presented when subjects are awake or in REM stages. Furthermore, the specific and crucial role of SWS (Slow-Wave Sleep, a stage of NREM sleep) in memory consolidation has been demonstrated in a study where, through electrical stimulations, slow oscillations were induced and boosted; because of this SWA increase, participants had a better performance in declarative memory tasks. Not only SWA helps learning, but it is also crucial, because its suppression has been demonstrated to impair declarative memory consolidation.