Sleeping and Dreaming Are Necessary For Memory Consolidation

I often wake up in the morning and want to continue the dream I was having when I was becoming more conscious. Why is it the best dreams seem to happen just before you wake up? Unfortunately, as many times as I rewind it in my mind, and add more, it never seems to come to the end I want it to. It’s frustrating.

Even more frustrating, you vividly remember that dream throughout the day, and want to recreate it again when you go to bed that night – but can’t. It’s like a story that has no ending, and you feel incomplete.

Evidence has proven that sleep plays an important role in memory consolidation and improvement, at least for procedural/skill memory, and the best time for these functions to take place is in the deep stages of dreaming.  New sleep studies support a view of a “memory life-cycle”, which involves three stages —stabilization, consolidation, and re-consolidation. Initial stabilization of memories may take as much as six hours, so for this reason a body needs at least 6-8 hours of sleep nightly.

Carl Jung and Sigmund Freud were the first to state that dreams are an interaction between the unconscious and the conscious. They both believed that the dominant portion of our brain is the unconscious, and dreams conveys a combination of all the things we have experienced or fear during waking hours. The only difference is that, since everything we take in and is processed through our short-term memory is encoded. Scientists just don’t understand how the encoding is interpreted.

A dream is the experience of all types of images, emotions, ideas, sounds, or other sensations during sleep. The events of dreams are often impossible, or unlikely to occur in physical reality, and are often baffling as to their meaning when trying to put them into context during waking times.

There are two major types of sleep, the REM (rapid eye movement stage) and the NREM (non-REM or early stage of sleep), as well as four minor portions of the NREM stage. REM sleep is the time when we are supposed to get the most restful sleep, and when scientists have mostly believed was we do our most dreaming. REM usually occurs in 90-minute cycles and alternates between the other types of sleep grouped into the NREM sleep stages. In the NREM sleep, the SWS (slow-wave sleep) stage is the time when it is most difficult for people to be awakened.

A study in 2001 about sleep and memory showed dreaming during REM stages of sleep may help to strengthen the linking and consolidation of semantic memories (not linked to any particular experience). This happens because the flow of information between the neocortex (part of the brain involved in higher functions such as sensory perception, generation of motor commands, spatial reasoning, conscious thought and language) and the hippocampus (plays important roles in the consolidation of information from short-term memory to long-term memory and spatial navigation) during REM sleep is reduced.

Because our brain is never totally at rest, it still needs to carry out thousands of functions in order to connect, disconnect, consolidate and clean itself up. We need to get sleep in order for these functions to be carried out without outside distractions. You can liken it to a defrag on your computer, where all your brain files are consolidated and open space cleaned out in order for the brain to work more efficiently. Without sleep our brains are not able to work to optimum capacity, and too much deprivation of sleep can lead to accelerated aging of the brain. Sleep and memory do go together.

A part of the consolidation of semantic memories is the linking of distant but related memories. According to Jessica D. Payne and Lynn Nadel, researchers from the University of Arizona Department of Psychology in Tucson, these memories are then “consolidated into a smooth narrative, similar to a process that happens when memories are created under stress.” Late in the REM sleep stage, the brain increases its levels of cortisol, a stress hormone that allows the brain to slow down and process information accumulated throughout the day.

German physician Robert, W. Der Traum (1886) was the first to suggest that dreams are needed to either erase a sensory impression that was not fully developed during the waking state, or for the brain to complete the impression and mark it to memory. You could liken his idea to cleaning out the junk from our memories. In 1971 researchers Hennevin and Leconte went on to add that dreams offered a way for the brain to handle and consolidate what had been taken in, and that dreams “are a result of the spontaneous firing of neural pattern while the brain is undergoing memory consolidation while sleeping.”

So, in answer to the title question: Can dreams make you smarter? The jury may be out on that, but all indications are that without dreams the brain is not able to perform the full “defrag” that allows us to function at optimum levels, and that REM sleep and SWS stages of dreaming may be important for memory processing and memory improvement.

 

 

About the author:

Ron White is a two-time U.S.A. Memory Champion and memory expert. As a memory speaker he travels the world to speak before large groups or small company seminars, demonstrating his memory skills and teaching others how to improve their memory, and how important a good memory is in all phases of your life.

 

 

Sources:

CHS Press, Learning Memory – Sleep, dreams, and memory consolidation: The role of the stress hormone cortisol : http://learnmem.cshlp.org/content/11/6/671.full

Wikipedia – Dreams: http://en.wikipedia.org/wiki/Dream

Mempowered – The Role of Sleep In Memory: http://www.memory-key.com/improving/lifestyle/activity/sleep

New World Encyclopedia – Dream: http://www.newworldencyclopedia.org/entry/Dream

Dr. Jessica D. Payne and Lynn Nadel – Sleep, dreams, and memory consolidation: The role of the stress hormone cortisol : http://learnmem.cshlp.org/content/11/6/671.full

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