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Printing:Sleep: The Ultimate Brainwasher and the Effects of Sleep

Deprivation

Authors: Christina Randle, Dominique McCoy, and Michael Alford.

Abstract

It has been proven than sleep deprivation has apparent effects on brain functionality. Many studies have been performed in which participants are subjected to neurological testing after a restful sleep as well as after an extended period of sleep deprivation. In J Lim’s study, participants were exposed to a string of pictures including faces, houses, and scrambled images. Researchers observed the response time as well as the ability of participants to identify the presence of distinct images. They found that sleep deprived participants had a lower attention span and were much less likely to acknowledge the pictures of faces in the string of images. This suggests that sleep deprivation directly inhibits the ability of the brain to focus on a specific activity or item for a long period of time.

Methodologies

Twenty-three healthy young adult volunteers underwent fMRI after a

normal night of sleep (RW) and after sleep deprivation in a

counterbalanced manner while performing a selective attention task.

During this task, pictures of houses or faces were randomly interleaved

among scrambled images. Across different blocks, volunteers responded to

house but not face pictures, face but not house pictures, or passively

viewed pictures without responding. The appearance of task-relevant

pictures was unpredictable in this paradigm. SD resulted in less accurate

detection of target pictures without affecting the mean false alarm rate or

response time. In addition to a reduction of fronto-parietal activation,

attending to houses strongly modulated parahippocampal place area (PPA)

activation during RW, but this attention-driven biasing of PPA activation was

abolished following SD. Additionally, SD resulted in a significant decrement

in functional connectivity between the PPA and two cognitive control areas,

the left intraparietal sulcus and the left inferior frontal lobe.

Results

It can be seen in table 1 that participants who had been

deprived of adequate rest (SD) had reaction times that were

noticeable slower than when they had experienced a full

night of sleep (RW). Patients were also less focused on the

task before them when they had suffered from sleep

deprivation. They had much lower “Hits” percentages

because they failed to recognize the presence of a

detectible picture in front of them during the cognitive

testing. Participants who had not received adequate sleep

were unable to distinguish between scrambled images and

distinctive images over a period of time. This reflects a

decrease in cognitive function.

Conclusions

From these studies, it can be concluded that sleep deprivation has

deleterious effects on cognitive function. The brain uses sleep time to

restart and recover from use during the day. Without this important

time to revamp, the brain cannot function correctly. The study done by

J Lim declares that sleep deprivation directly inhibits the ability of the

brain to function on a specific activity or topic for an extended period

of time. This results in a decreased attention span and an inability to

focus on a single topic. This is especially relevant in a college setting

because the majority of students do not receive an adequate amount

of sleep each night. This reduced amount of sleep results in

decreased cognitive function and a loss in ability to focus in class.

This is also applicable to students who chose to pull “all nighters”

before big tests to study. Many students believe that they are better

off when they spend the entire night before a test studying and do not

sleep, but studies such as these suggest that the exact opposite may

be true. If lack of sleep really does decrease cognitive function, then a

good night’s sleep before a big test is just as important preparation as

studying the material.

The image below depicts brain activity within participants as they looked at the

string of pictures. The top row reflects the cognitive response of participants

after sleep deprivation (SD) while the bottom row reflects the response after a

normal night of sleep (RW). There is a noticeably lower amount of brain activity

in participants who had not received adequate sleep.

Methodologies

References

• 1.Lim, Julian, Jiat Chow Tan, Sarayu Parimal, David F.

Dinges, and Michael W. L. Chee. “Sleep Deprivation

Impairs Object-Selective Attention: A View From the

Visual Cortex?” Public Library of Science. U.S. National

Library of Medicine, 02 May 2010. Web. 15 Nov. 2013.

• 2. Hamilton, Jon. "Brains Sweep Themselves Clean Of

Toxins During Sleep." NPR. NPR, n.d. Web. 1 Nov.

2013.