Good sleep brings out the best
Thomas Dekker said: “Sleep is that golden chain that ties health and our bodies together.” The latest insomnia statistics are frightening. They show that more than 30% of the population suffers from insomnia. What exactly does this mean for an individual one might ask themselves. Besides feeling worn out there’s a cognitive tax we must pay.
Various studies show that lack of sleep lowers our cognitive ability. The sleep debt we gain over the week transfers into the next week if we don’t make up for the sleep deficit. That is true for everyone, not only for those who suffer from insomnia. The same way as lack of sleep is destructive, enough sleep empowers our cognition. Let’s take a closer look at that.
- Sleep promotes insight
Wagner and his colleagues, demonstrated a unique relationship between sleep and learning in the form of insight gain. Mednick and Drummond wrote about this experiment in INSOM Issue 3, 2004: “Post-training, nocturnal sleep significantly increased the proportion of participants who gained insight into a hidden rule of the trained task. Participants were tested on the Number Reduction Task (NRT) before and after one of the following: a night of sleep, a night of sleep deprivation or a full day of waking. The NRT may be accurately performed using two possible methods. The first is an explicitly presented, brute force method whereby subjects apply two simple rules across seven steps to determine the final answer. The second requires divining the hidden structure of the task thereby allowing ‘solvers’ to leap ahead to the final answer after only two steps. Insight was determined as the moment participants were able to jump to a final answer without completing the entire trial, as well as being able to explicitly state the hidden rule. Wagner et al. found that participants who slept between tests gained significantly more insight than either of the waking groups.” We can conclude that enough sleep makes you better at logical deduction.
- Sleep strengthens retention
Another experiment from 1996 done by Skaggs and McNaughton revealed what goes on in rat’s brain while it sleeps. Awake, the rat, was learning to walk through a maze. The electrodes placed on the rat, measured activity of certain neurons in the brain, which process information as we are learning. The researchers detected a specific pattern of electric impulses. When the rat fall asleep the electrodes were still attached and the brain activity was still being monitored. It showed that the brain was repeating the same electrical pattern as before while the rat was awake and learning. The pattern repeated itself over and over again at great speed. This leads to conclusion, that while we sleep the brain reinforces that, what we were learning before falling asleep.
The abstract of Skaggs’ and McNaughton’s paper tells us: “The correlated activity of rat hippocampal pyramidal cells during sleep reflects the activity of those cells during earlier spatial exploration. Now the patterns of activity during sleep have also been found to reflect the order in which the cells fired during spatial exploration. This relation was reliably stronger for sleep after the behavioral session than before it; thus, the activity during sleep reflects changes produced by experience. This memory for temporal order of neuronal firing could be produced by an interaction between the temporal integration properties of long-term potentiation and the phase shifting of spike activity with respect to the hippocampal theta rhythm.” Various other studies showed the same is true for humans. Memory representations are reactivated during slow-wave sleep after learning, and these reactivations cause a beneficial effect of sleep for memory consolidation.
- Sleep promotes neurogenesis
The recent research showed that even adults grow and develop nervous tissue. The process is called neurogenesis. Deng, Aimone and Gage (2010) wrote: “newborn neurons at different maturation stages may make distinct contributions to learning and memory. In particular, computational studies suggest that, before newborn neurons are fully mature, they might function as a pattern integrator by introducing a degree of similarity to the encoding of events that occur closely in time.”
Neurogenesis is an important developing and growing area in scientific research. Frontiers in cellular neuroscience published an article Detrimental role of prolonged sleep deprivation on adult neurogenesisin 2015. Sleep deprivation tends to cause harm to neurogenesis, which in consequence can influence our memory and learning ability. Of course it is necessary to mention that sleep is only one of the the factors which influence neurogenesis. Important are also exercise, food we eat, age etc.
We all increasingly face daily distress, sleeplessness, lack of concentration and possibly burnout. It has become a necessity to sleep well in order to function well. Good sleep really does bring out the best – it can help our logical deduction, memory and learning. In this article we focused only on cognitive benefits of good sleep.
Sleep also affects our health: “Numerous studies have found that insufficient sleep increases a person’s risk of developing serious medical conditions, including obesity, diabetes, and cardiovascular disease.” Let’s be responsible and take good care of our sleep.