It is well established in the scientific community that memories are replayed and consolidated during sleep. In particular during our deepest non-REM stages of sleep. During this replay the memory is either coded into long term memory or considered unimportant and left in short term memory that over the coming days or weeks will get weaker and weaker unless something happens to reinforce it.
The mechanisms for why one memory is stored and another isn’t are still not completely understood but has it’s foundations in past events of emotional significance.
Recent research shows that there is a different brainwave signature present during the successful coding of a memory versus an unsuccessful one. And by artificially manipulating these brainwaves they are able to control whether or not a memory (like learning how to do a task) is remembered and transferred into a more skilled performance the next day.
What the researchers found was that if Delta waves (0.5-4Hz) were present during memory replay that the memory is not coded into long term memory and therefore easier to forget. Whereas if slow waves (<1Hz sometimes called Epsilon) were present then the coding did take place and the memory or skill was learnt and subsequently built upon. Present also are Gamma sleep spindles that are already understood by scientists to play a vital role in memory.
This potentially could lead to better ways to help people ‘forget’ things like trauma that causes PTSD for example.
Not only is this interesting regarding potential therapeutic use, by it really does highlight the importance of those deep sleep stages. And by the way, drug induced sleep, either by recreational or medical drugs.., will often interfere with this deep sleep cycle. Drugs in general knock you out rather than help you fall naturally asleep. The result is not the same.
For brainwave entrainment practitioners, using a slow brainwave session at the end of a busy day may help you improve how much you remember and lead to an evolving skill-set rather than a repeating stagnant one.
Which is how the mind body system learns and grows.