Learning While Sleeping

I often hear people talking about power naps, and problem solving while sleeping.
I’ve been told it’s good to imagine taking out the garbage from your brain before going to sleep.  I’ve met several people that insist on taking naps to boost their creativity regardless of how close they are to a deadline. It’s hard to say if it works or not based on individual anecdotes.  And if it does work, why don’t we have more of a napping culture? I think it’s safe to say, in the work culture in the US, napping isn’t widely used as a tool for creative thinking or well being.  I wanted to find out what the science was behind learning while sleeping and the kind of research that’s happening in that area.

There is a lot of research on activity in the brain while we sleep, but most of the studies I could find, focus on testing people through questionnaires or problem solving before and after sleep. The results of many studies show that people are better at solving problems after sleeping. It’s that simple. I couldn’t find a single paper that challenges that finding.

So if sleeping is good for problem solving, what’s happening in the brain? If I were to build a piece of technology that would assist in the process, I thought it would be critical to understand exactly what’s happening during sleep that enhances our ability to solve problems. There are a series of studies that look at activity in rat brains during REM sleep.  Many of these studies look at disrupting REM to understand the effects of sleep deprivation, but only a handful seem to be focused on the positive effects of REM sleep. A small set of studies starting in the 1950’s have brought some light into how we learn while sleeping.

In the 1950s, scientists studying the rabbit hippocampus (the area of the brain related to memory and spacial navigation) noticed various animals had a rhythmic firing of neurons in the hippocampus during moments of intense awareness. Each animal’s state of intense awareness differed, but many involved scenarios of fear or survival.

They named this periodic pulsing of neurons, the “theta rhythm”.  It wasn’t until years later when it was discovered that the same theta rhythms appeared during sleep.  In 1972 Jonathan Winson theorized that the same theta rhythms appeared during sleep because the animal was dreaming about experiences prior to sleeping.

In a 1997 paper, scientists show that patterns of hippocampal neurons during sleep have similar patterns to recordings prior to sleep. By recording two neurons in a rat’s hippocampus firing simultaneously and comparing their temporal bias during sleep prior to their maze experience, bias in the maze, and bias during sleep after the maze, they were able to compare the patterns for similarities. In this study, they have been able to show a close correlation between patterns fired in hippocampus pairs (HC-HC) during the rat’s sleep after it experienced the maze (Bias s2) and patterns fired while going through the maze (Bias m).

This study leads me to imagine a possible device in the future that records neural activity in the brain, to replay it back by stimulating neurons as a way to relive a scenario while sleeping, much like the SQUID in the sci-fi movie, Strange Days. It would be amazing to program dreams as a way to enhance learning, memory and general well being.

 

 

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http://www.psychologytoday.com/blog/conquering-cyber-overload/201005/sleep-success-creativity-and-the-neuroscience-slumber
In a study titled “Sleep Inspires Insight,”[6]  participants were given puzzles that involved finding the final number to complete a series of digits. The way they were trained to solve the puzzle was to compare every two-digit pair in the series. What they were not told was that there was a shortcut that allowed people to identify the solution after only two steps. Participants performed three trials of the puzzle and then were given an eight-hour break before returning for ten more trials. Some of them slept during the break and some did not. The people who slept between the two sessions were twice as likely as the others to discover the easier way to solve the problem. According to the researchers, sleeping on a problem apparently allows for a restructuring of the brain connections, “setting the stage for the emergence of insight.”
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http://rstb.royalsocietypublishing.org/content/352/1360/1525
Hippocampal cells that fire together during behaviour exhibit enhanced activity correlations during subsequent sleep, with some preservation of temporal order information. Thus, information reflecting experiences during behaviour is re–expressed in hippocampal circuits during subsequent ‘offline’ periods, as postulated by some theories of memory consolidation. If the hippocampus orchestrates the reinstatement of experience–specific activity patterns in the neocortex, as also postulated by such theories, then correlation patterns both within the neocortex and between hippocampus and neocortex should also re–emerge during sleep. Ensemble recordings were made in the posterior parietal neocortex, in CA1, and simultaneously in both areas, in seven rats. Each session involved an initial sleep episode (S1), behaviour on a simple maze (M), and subsequent sleep (S2). The ensemble activity–correlation structure within and between areas during S2 resembled that of M more closely than did the correlation pattern of S1. Temporal order (i.e. the asymmetry of the cross–correlogram) was also preserved within, but not between, structures. Thus, traces of recent experience are re–expressed in both hippocampal and neocortical circuits during sleep, and the representations in the two areas tend to correspond to the same experience.
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http://www.sciencedirect.com/science/article/pii/S0006899399023100

http://seedmagazine.com/content/article/how_we_know/?page=4

https://medium.com/better-humans/dfb12da75a3d

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http://scienceblogs.com/cortex/2007/05/01/thinking-during-sleep/
While evidence for the role of sleep in creative problem-solving has been looked at by prior research, underlying mechanisms such as different stages of sleep had not been explored. Using a creativity task called a Remote Associates Test (RAT), study participants were shown multiple groups of three words (for example: cookie, heart, sixteen) and asked to find a fourth word that can be associated to all three words (sweet, in this instance). Participants were tested in the morning, and again in the afternoon, after either a nap with REM sleep, one without REM or a quiet rest period. The researchers manipulated various conditions of prior exposure to elements of the creative problem, and controlled for memory.

“Participants grouped by REM sleep, non-REM sleep and quiet rest were indistinguishable on measures of memory,” said Cai. “Although the quiet rest and non-REM sleep groups received the same prior exposure to the task, they displayed no improvement on the RAT test. Strikingly, however, the REM sleep group improved by almost 40 percent over their morning performances.”
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http://link.springer.com/article/10.3758%2Fs13421-012-0256-7
We presented participants with a set of remote-associate tasks that varied in difficulty as a function of the strength of the stimuli–answer associations. After a period of sleep, wake, or no delay, participants reattempted previously unsolved problems. The sleep group solved a greater number of difficult problems than did the other groups, but no difference was found for easy problems. We conclude that sleep facilitates problem solving, most likely via spreading activation, but this has its primary effect for harder problems.
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