Sleep And Memory

January 3, 2017

By Anne Foy, Guest Contributor

For some years now, the world appears to have seen sleep as an inconvenience. Sure, we acknowledge that it’s something which needs to happen. We’re even aware of the dire consequences [1] of not getting enough sleep [2]. But we nonetheless try to push it to the margins of our existence. We force ourselves out of bed before we’re fully awake, and, at the other end of the day, bludgeon our exhausted brains into keeping us awake for longer. We stifle sleep with caffeine, or bring it on artificially with pills [3]. We try to make it into our servant, to be called upon at times of our choosing and hidden away when not wanted. Little wonder that so many of us are struggling with sleep disorders. However, poor sleep does a lot more than simply make us feel groggy and slow. Over time, chronic lack of sleep can have a very serious impact upon your cognition. In particular, sleep is associated with good memory function - so much so that disordered sleeping habits are associated with dementia.

More Than Just ‘Recharging’ Time

There is a common misconception that sleep is about ‘switching off’ in order to ‘recharge’. Humans aren’t cellphones, however. We’re far, far more complicated than that. Sleep is in fact the time when your body and mind carries out some of its most complex operations - the kind of thing it doesn’t want your conscious mind and day to day life interrupting. This is why doctors and healthcare providers [4] are eager for patients to sleep well - without good sleep, a lot of these vital health and maintenance operations go undone, leading to myriad health issues down the line. One of these vital operations is the sorting and processing of memories. We’ve known for a long time that sleep plays an incredibly important role in healthy memory, but haven’t been entirely sure precisely what it does or how it does it. Recently, however, a lot of facts about sleep and memory have been discovered [5] - and revealed serious implications about lack of sleep and cognitive decline.

Deep Sleep Neuron Connections

When we’re in deep, ‘slow-wave’ sleep, our brains effectively ‘replay’ what we’ve experienced during the day. As we’re asleep, it’s able to do this without cognitive interruption, and therefore ‘concentrate’ (for want of a better word) on what it’s experienced. During deep sleep, scientists have observed [6] brains making lots of new connections between neurons. New connections forming between neurons is what ‘learning’ looks like from a neurobiological perspective. From a psychological perspective, ‘learning’ involves taking memories, extrapolating from them, and then storing those memories in ‘long-term’. This is the process the scientists observed occurring in the brains of sleeping subjects.

Lack Of Sleep And Dementia

Quite obviously, if your brain uses its deep sleep time to sort through, store, and learn from memories, a lack of deep sleep is going to cause issues with memory. However, it seems to go a lot deeper than the odd spate of simple forgetfulness. Studies show that disturbed sleep patterns can significantly increase one’s chances of developing dementia. As yet, nobody is entirely sure why this should be the case, but the facts are indisputable [7], and many are reasonably sure that it has something to do with sleep’s role in memory formation. Some speculate that lack of usage during deep sleep causes the brain's memory-retention functions to degrade. Others believe that lack of sleep generally puts an inordinate amount of strain on the brain, causing cell death and therefore cognitive decline.All in all, whatever is actually going on inside the skull, if you want to learn more, remember more, and generally maintain good cognitive health, it’s best to sort out your sleep cycle - and quickly!

[1] Think!, “Fatigue”, UK Government

[2] Mercola, “How Dangerous Is Sleep Deprivation, Really?”, Mar 2014

[3] Ny Daily News, “CDC: 9 million Americans use prescription sleeping pills”, Aug 2013

[4] Q, "health cover"

[5] James Gallagher, “Sleep’s memory role discovered”, BBC, Jun 2014

[6] Guang Yang, Cora Sau Wan Lai, Joseph Cichon, Lei Ma, Wei Li, Wen-Biao Gan, “Sleep promotes branch-specific formation of dendritic spines after learning”, Science, Jun 2014

[7] Caroline Cassels, “Disturbed Sleep Linked To Increased Dementia Risk”, Medscape, Jul 2014


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