Learning occurs in three phases: acquisition, consolidation and recall. The names suggest what each phase is about. During acquisition, new information is introduced to the brain. Consolidation refers to the firming and retention of this new information for future use. Recall is using this information later on when it becomes essential.
Sleep plays a huge role in the learning process. If you get too little sleep (i.e., are sleep deprived), your fatigue and lack of attention will make the first phase of acquisition more difficult as your focus will be off. Likewise, if you sleep poorly, your consolidation of new information will be affected negatively.
Scientists are not entirely clear how sleep helps us process and retain new information, but they are certain that it plays a huge role. Specifically, they now say that different types of brainwaves during varying stages of sleep are associated with the formation of particular types of memory.
For instance, the consolidation of fact-based information — associated with what’s called declarative memory — once seemed to be served best during REM, or rapid eye movement, sleep, which is also the type of sleep in which we dream most frequently. But now, scientists say that declarative memory is also aided by slow-wave sleep (SWS), which is deep, restorative sleep.
Procedural memory, or “how to do something,” is also best served by REM, though again, SWS comes into the picture. Specifically, motor learning seems to depend on lighter stages of sleep for consolidation. Visual learning, on the other hand, seems to depend on the amount and timing of both SWS and REM.
Questions remain, however, since certain medications can suppress REM sleep entirely, even though people so affected generally do not show any loss of ability to consolidate knowledge. Even tests on rats being deprived of REM sleep are inconclosive, scientists say. One camp, noting the rats’ next-day difficulty in learning, attributes the difficulty to lack of REM sleep. Other scientists claim the result derives from a general lack of sleep — fatigue — rather than just the interrupted REM cycle.
The bottom line, though, is clear to all researchers: Sleep is essential to learning and memory, and sleep deprivation militates against both. At any rate, if you have sleep problems, you should seek professional help, not just for the sake of learning, but for the sake of your health and overall well-being.