1 sleepless night increases dopamine in the human brain

August 19, 2008

Just one night without sleep can increase the amount of the chemical dopamine in the human brain, according to new imaging research in the August 20 issue of The Journal of Neuroscience. Because drugs that increase dopamine, like amphetamines, promote wakefulness, the findings offer a potential mechanism explaining how the brain helps people stay awake despite the urge to sleep. However, the study also shows that the increase in dopamine cannot compensate for the cognitive deficits caused by sleep deprivation.

"This is the first time that a study provides evidence that in the human brain, dopamine is involved in the adaptations that result from sleep deprivation," said Nora Volkow, MD, director of the National Institute on Drug Abuse, who led the study.

Volkow and colleagues found that in healthy participants, sleep deprivation increased dopamine in two brain structures: the striatum, which is involved in motivation and reward, and the thalamus, which is involved in alertness. The researchers also found that the amount of dopamine in the brain correlated with feelings of fatigue and impaired performance on cognitive tasks.

"These findings suggest dopamine may increase after sleep deprivation as a compensatory response to the effects of increased sleep drive in the brain," said David Dinges, PhD, at the University of Pennsylvania School of Medicine, an expert unaffiliated with the study. "The extent to which this occurs may differentiate how vulnerable people are to the neurobehavioral effects of sleep loss," Dinges said.

The researchers studied 15 healthy participants who were either kept awake all night or allowed a good night's sleep. Researchers tested the same participants in both conditions. On the morning of the study, participants rated how tired they were and did cognitive tasks testing visual attention and working memory.

The researchers used the imaging technique positron emission tomography to study the changes in the dopamine system that occur with sleep deprivation. Compared to well-rested participants, sleep-deprived participants showed reduced binding of a radiolabeled compound ([11C]raclopride) that binds to dopamine receptors in the striatum and thalamus. Because raclopride competes with dopamine for the same receptors, decreased raclopride binding indicates increased levels of dopamine, according to the study authors.

Although decreases in raclopride binding could also indicate a reduction in the number of dopamine receptors, these findings are consistent with prior research implicating increased dopamine levels in wakefulness. For example, some stimulants that prevent sleep, like amphetamines, increase dopamine in the brain, and sleepiness is common in people with Parkinson's disease, which kills dopamine neurons.

The rise in dopamine following sleep deprivation may promote wakefulness to compensate for sleep loss. "However, the concurrent decline in cognitive performance, which is associated with the dopamine increases, suggests that the adaptation is not sufficient to overcome the cognitive deterioration induced by sleep deprivation and may even contribute to it," said study author Volkow.

Future research will examine the long-term effects of chronic sleep disturbances on dopamine brain circuits.

Source: Society for Neuroscience

Explore further: Mouse model of Parkinson's reproduces nonmotor symptoms

Related Stories

Mouse model of Parkinson's reproduces nonmotor symptoms

June 23, 2009

The classic symptoms of Parkinson's disease involve tremor, stiffness and slow movements. Over the last decade, neurologists have been paying greater attention to non-motor symptoms, such as digestive and sleep problems, ...

How does the brain work? The 100-billion neuron question

October 27, 2010

(PhysOrg.com) -- For centuries, the brain has been the subject of countless philosophical and scientific debates. Recently, many discoveries and theories have cropped up around how the brain works, and those theories are ...

Brain tweak lets sleep-deprived flies stay sharp

July 31, 2008

Staying awake slows down our brains, scientists have long recognized. Mental performance is at its peak after sleep but inevitably trends downward throughout the day, and sleep deprivation only worsens these effects.

Recommended for you

How the finch changes its tune

August 3, 2015

Like top musicians, songbirds train from a young age to weed out errors and trim variability from their songs, ultimately becoming consistent and reliable performers. But as with human musicians, even the best are not machines. ...

Machine Translates Thoughts into Speech in Real Time

December 21, 2009

(PhysOrg.com) -- By implanting an electrode into the brain of a person with locked-in syndrome, scientists have demonstrated how to wirelessly transmit neural signals to a speech synthesizer. The "thought-to-speech" process ...


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.