How the brain reacts to sleep deprivation

April 5, 2017, Forschungszentrum Juelich
EEG scan. Credit:  Forschungszentrum Jülich / Ralf-Uwe Limbach

In a new study, scientists from Forschungszentrum Jülich together with partners from the German Aerospace Center (DLR) have investigated the molecular changes with which the human brain reacts to exceptionally long wake phases. The test subjects stayed awake for 52 hours and then had their brains scanned at Jülich's PET Centre. Subsequently, they were taken to DLR in Cologne, where – monitored by the scientists – they were able to catch up on their sleep for 14 hours.

Lack of sleep can severely affect our performance and health. Moreover, a lack of sleep causes changes in the brain which the researchers were able to measure in their experiment. "Our investigations have shown that sleep deprivation increases the number of available A1 receptors. Thanks to the subsequent sleep phase, they then normalized back to the initial level," reports PD Dr. David Elmenhorst from Jülich's Institute of Neuroscience and Medicine (INM-2).

The A1 adenosine receptors are built into the cell wall as a type of receiver. Their function is to forward the signal from adenosine, the docking chemical messenger, to the interior of the cell, where it decreases the cell's activity. It is thought that not only the adenosine itself but also the A1 receptors are responsible for the urge to sleep, which becomes stronger the longer a person stays awake. Adenosine is an elementary product of the energy metabolism. Its concentration varies practically second by second. The number of free receptors, in contrast, changes much more slowly and thus seems better suited for a kind of "sleep memory."

Average adenosine receptor density after a 52-hour wake phase (top) and after 14 hours of sleep (bottom). Credit:  Forschungszentrum Jülich
Resistant to sleep deprivation

The effect of caffeine is also associated with this type of receptor. The stimulant accumulates at complex protein molecules and blocks them. In this series of experiments, the test subjects had to do without coffee and other invigorating substances. During their 52-hour wake phase, they were subjected to several performance tests: pressing buttons to measure their reaction time and memorizing words to determine their memory performance. One striking feature was the individual differences in performance: some of the sleep-deprived participants displayed extreme lapses, sometimes lasting several seconds, while in others a performance drop was hardly measurable. Such a predisposition could be advantageous for jobs in which people regularly have to perform reliably in spite of lacking sleep.

"Astonishingly, we did not measure a constant value of A1 receptor density in this seemingly resistant group of test subjects, but a large increase," reports David Elmenhorst. The higher value does not correspond to an exceptionally high concentration of receptor molecules, however, since positron emission tomography (PET) records only a net value. Tracer molecules in the blood stream of the test subjects dock to free receptor molecules and can be observed in the PET scanner when they decay. In this manner, only those receptors are recorded that are not blocked and therefore available at the time of measurement. "Our theory is, therefore, that the with high A1 receptor density produce relatively little adenosine and thus inhibit the cell activity to a lesser degree," says Elmenhorst. Consequently, the total number of free is higher at the time of the PET measurement.

Relevant for treating depression

These findings are also of relevance for clinical medicine: sleep deprivation is a quick tool against depression, but only effective for a short time. "There are many efforts to increase the duration of the therapeutic effects of in the treatment of depression. But the problem so far is that when people sleep again just once they often fall back into their depressed state," says David Elmenhorst. A better understanding of the interrelations between mood and adenosine regulation could thus contribute to optimizing the design of wake therapies.

Explore further: New role of adenosine in the regulation of REM sleep discovered

More information: David Elmenhorst et al. Recovery sleep after extended wakefulness restores elevated Aadenosine receptor availability in the human brain, Proceedings of the National Academy of Sciences (2017). DOI: 10.1073/pnas.1614677114

Related Stories

New role of adenosine in the regulation of REM sleep discovered

September 1, 2016
The regulation and function of sleep is one of the biggest black boxes of today's brain science. A new paper published online on August 2 in the journal Brain Structure & Function finds that rapid eye movement (REM) sleep ...

Astrocytes identified as target for new depression therapy

January 23, 2013
Neuroscience researchers from Tufts University have found that our star-shaped brain cells, called astrocytes, may be responsible for the rapid improvement in mood in depressed patients after acute sleep deprivation. This ...

Finding the roots of memory impairment from sleep deprivation

June 10, 2011
Anyone who has pulled an all-nighter knows there is a price to be paid the next day: trouble focusing, a fuzzy memory and other cognitive impairments. For students, these impairments might just result in a bad grade. But ...

Recommended for you

Wiring diagram of the brain provides a clearer picture of brain scan data

December 14, 2018
Already affecting more than five million Americans older than 65, Alzheimer's disease is on the rise and expected to impact more than 13 million people by 2050. Over the last three decades, researchers have relied on neuroimaging—brain ...

Scientists identify method to study resilience to pain

December 14, 2018
Scientists at the Yale School of Medicine and Veterans Affairs Connecticut Healthcare System have successfully demonstrated that it is possible to pinpoint genes that contribute to inter-individual differences in pain.

Parents' brain activity 'echoes' their infant's brain activity when they play together

December 13, 2018
When infants are playing with objects, their early attempts to pay attention to things are accompanied by bursts of high-frequency activity in their brain. But what happens when parents play together with them? New research, ...

In the developing brain, scientists find roots of neuropsychiatric diseases

December 13, 2018
The most comprehensive genomic analysis of the human brain ever undertaken has revealed new insights into the changes it undergoes through development, how it varies among individuals, and the roots of neuropsychiatric illnesses ...

Researchers find the cause of and cure for brain injury associated with gut condition

December 13, 2018
Using a mouse model of necrotizing enterocolitis (NEC)—a potentially fatal condition that causes a premature infant's gut to suddenly die—researchers at Johns Hopkins say they have uncovered the molecular causes of the ...

Researchers discover abundant source for neuronal cells

December 13, 2018
USC researchers seeking a way to study genetic activity associated with psychiatric disorders have discovered an abundant source of human cells—the nose.

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.