Research Paper - How Does Sleep or Rest Improve Memory?

Introduction

The strategic adaptation of organisms involves essential phenomena such as the ability to form memories, which is critical to the dynamic environmental demands. Theories and research studies indicating that sleep is beneficial to memory have had a continuous and long history dating back to the earliest experimental memory researches and fitted with different concepts and conclusions. During the past few decades, 'memory and sleep' research has been very active with several claims and counterclaims concerning the effects of sleep on memory and the various findings. Nonetheless, definitions of sleep and memory remain fairly constant.

Sleep is conventionally defined as the reversible and natural state of the body and mind characterized by loss of consciousness, relative inactivity, and a minimal responsiveness to external stimuli. Memory on the other hand is an indispensable and fundamental adaptation enabling state comprising three major sub-processes, which include retrieval, consolidation, and encoding. Encoding involves the perception of a particular stimulus resulting into a memory trace while consolidation comprises multiple short and long-term waves of the consolidation processes and finally retrieval involves the recollection and accessing of the stored memories.

Background

Throughout history, humanity's devotion to perpetual commitments has been met with varied responses concerning the resultant effects and consequences. Some contend that perpetual commitments without rest or with limited rest are not particularly healthy and does not translate to greater productivity, while others oppose this notion and argue that there is no conclusive evidence that the reverse attracts or is associated with negative ramifications. Several scholars and researchers have proposed numerous theories and interpreted several empirical findings concerning the relationship between sleep, rest, and memory.

Current research indicates that as much as the individual is daydreaming or relaxing, the brain does not stop working. Similar to the manner in which an array of physiological, genetic, and molecular processes occur at night during sleep, several significant mental processes also require a 'downtime' or a type of rest.

This is because 'downtime' has a positive effect of replenishing the brain's stores of motivation and attention, thus, encouraging creativity and productivity. Furthermore, 'downtime' is an essential component that is very instrumental and beneficial in forming stable memories and achieving the highest performance levels possible.

Literature Review

This literature review delves into four peer reviewed articles concerning the relationships between sleep, rest, and memory. The effects of how sleep and rest impacts memory have been elucidated in this review and interpretations of the findings have been underscored. These peer reviewed articles are based on empirical researches conducted by various researchers, research bodies, and scholars. The first peer reviewed articles involves a research carried out by researchers at BIDMC (Beth Israel Deaconess Medical Center). The research lead author in this article is Mathew Walker, who is a director of BIDCMC's Neuroimaging and Sleep Laboratory and is also an Associate Professor at Harvard Medical School of Psychiatry.

In this article, a research was carried out using FMRI (Functional Magnetic Resonance Imaging) to establish and comprehend the role of sleep to learning and memory. Observations were recorded on the subjects being tested regarding which parts of the brain remained inactive and active during the research procedure. The researchers found that new memories were formed in the event that the subject engaged with information, which was meant to be learned.

Subjects were taught a series of skilled finger movement such as playing a piano and then they were tested on their abilities to recollect and remember these finger movements after some of them remaining awake for a certain period of time and some of them sleeping in the course of the experiment. Their brain activity according to their responses was recorded using an MRI.

It was noted that the subjects who had slept for a certain duration showed that despite variations in the brain activities according to the MRI results, they had better motor skills and performances in comparison to the ones who had remained awake during the entire research study (Walker & Stickgold). Walker and the other researchers concluded that sleep is vital and essential to human development, which involves learning and memorizing issues and events. Human growth and development involves immense amount of new experiences and material that needs to be learnt and memorized. Sleep therefore, becomes indispensable for successful learning and memory by the individual.

The second peer reviewed article involves a research conducted by several researchers including Leah Krubitzer, a professor and neuroscientist at the University of California (Center for Neuroscience) at Davis, Massimini and Tononi among others. Studies were conducted using EEG (ElectroEncephaloGraphy) to determine the manner in which the responds and behaves during sleep, and the relationship between sleep and memory.

Subjects in the research study were given nonsense syllables and later tested. These subjects were divided into two groups such that one group was allowed to sleep before conducting the tests while the other group remained awake throughout the entire research study period. Results revealed that the subjects who had been given the opportunity to sleep before being tested had better memories and recollection of the previously taught syllables than those who remained awake throughout the entire research study.

EEG results revealed that there were waves of electrical activities among the subjects who had a small duration of sleep in the research study and these waves peaked randomly and for a very short time. The researchers concluded that these waves altered the strengths of the synapses or connections between nerve cells and these synaptic changes resulting from either sleeping or learning form the fundamental framework of memory (Huber et.al).

The third peer reviewed article is concerned with sleep deprivation and its effects on the behavior, brain, and memory. A research was conducted at the Harvard Medical School (HMS) by researchers such as Joseph Martin, Diekelmann and several others concerning the effects of sleep deprivation on the brain, memory, and behavior. Subjects were given numerous tests after some of them being deprived of sleep while others were afforded the opportunity to sleep. During the tests researchers who included neuroscientists used various techniques to assist them in studying the subjects such as the use of MRI and EEG techniques among others. Test subjects were tested on imaginative and creative thinking, remembering a short series of simple statements, and ability to multitask.

Before the tests were conducted, subjects in the research study were separated into two groups with one group given the opportunity to sleep for a certain duration while the other group was distracted with various tasks and activities such that they could not sleep. When the tests were conducted, the test results revealed that the sleep deprived subjects had difficulties in multitasking or focusing on numerous related tasks and also in thinking of creative or imaginative ideas or words. This was contrary to the subjects who had been given the opportunity to sleep for a certain duration and their performances outstripped those of their comrades.

The researchers based on the test results concluded that sleep deprivation alters behavior, memory, and the brain such that sleep deprived individuals tend to be repetitive in different situations and have difficulties in making logical decisions for seemingly similar situations but quite different in reality. Their memories are distorted especially if it involves a particular order of events and they are unable to recall the correct sequence of previously presented situations.

The fourth peer reviewed article involves a research study conducted at the University of California, Riverside, by Sara Mednick, a sleep researcher at the University and other researchers. Sara conducted a research to establish the paradox involving input time and output obtained. Test subjects were given a list of activities to perform within a specified amount of time and the option to either sleep in between the research study or remain awake until completion of the exercise.

Among some of the tasks included answering a set of questionnaires in addition to some limited physical activities such as three-point shooting and free throws for basketball players. Subjects were given the option to spend a specified number of hours sleeping or complete their tasks without sleeping. The questionnaires had similar questions but, with different wordings and phrases. Results revealed that the test subjects who opted not to sleep and complete their tasks performed poorly in relation to those who opted to utilize the time and sleep for the time indicated in the research study.

Results also revealed that the test subjects who downplayed the essence of sleeping for the required time in the research study could not identify the similarities present of questions in the questionnaires thus, giving different answers for the same questions. The researchers held that sleep is indispensably important in minimizing the time consumed for successfully overcoming obstacles and improves performance by boosting memory and rational thinking (Mednick et.al).

Integration and Conclusion

Sleep and its effects on memory have undergone an evolutionary, revolutionary, and empirical process since the growth and development of humanity's intelligence. Various theories have been supplanted by empirical findings concerning the effects of sleep on memory and related issues. Human beings are not designed to expend energy continuously without some form of respite, which is best and naturally achieved through sleep.

The four peer reviewed articles mentioned in this paper all have a common denominator signifying that; lack of sleep or sleep deprivation is detrimental to the achievement of the highest performance standards and negatively affects memory capabilities within an individual. The empirical researches conducted in relation to examining the relationships between sleep and memory sufficiently underscore that sleep is an indispensable and significant component in enhancing memory and related elements towards the achievement of best performance at all levels.

References

Diekelmann, S., & Born, J.. The memory function of sleep. Nature Reviews Neuroscience, 11(2), 114-126.

Huber, R., Ghilardi, M. F., Massimini, M., & Tononi, G.. Local sleep and learning. Nature, 430(6995), 78-81.

Mednick, S. C., Makovski, T., Cai, D. J., & Jiang, Y. V.. Sleep and rest facilitate implicit memory in a visual search task. Vision research,49(21), 2557-2565.

Walker, M. P., & Stickgold, R.. Sleep-dependent learning and memory consolidation. Neuron, 44(1), 121-133.