Brain regions can take short naps during wakefulness, leading to errors
A photo of rats with objects introduced into their cages to keep them awake. Credit: Giulio Tononi, M.D., Ph.D., University of Wisconsin-Madison
If you've ever lost your keys or stuck the milk in the cupboard and the cereal in the refrigerator, you may have been the victim of a tired brain region that was taking a quick nap.
Researchers at the University of Wisconsin-Madison have a new explanation. They've found that some nerve cells in a sleep-deprived yet awake brain can briefly go "off line," into a sleep-like state, while the rest of the brain appears awake.
"Even before you feel fatigued, there are signs in the brain that you should stop certain activities that may require alertness," says Dr. Chiara Cirelli, professor of psychiatry at the School of Medicine and Public Health. "Specific groups of neurons may be falling asleep, with negative consequences on performance."
Until now, scientists thought that sleep deprivation generally affected the entire brain. Electroencephalograms (EEGs) show network brain-wave patterns typical of either being asleep or awake.
"We know that when we are sleepy, we make mistakes, our attention wanders and our vigilance goes down," says Cirelli. "We have seen with EEGs that even while we are awake, we can experience shorts periods of 'micro sleep.' "
Periods of micro sleep were thought to be the most likely cause of people falling asleep at the wheel while driving, Cirelli says.
But the new research found that even before that stage, brains are already showing sleep-like activity that impairs them, she says.
• Follow Medical Xpress on Facebook!
• Follow Medical Xpress on Twitter!
As reported in the current issue of Nature, the researchers inserted probes into specific groups of neurons in the brains of freely-behaving rats. After the rats were kept awake for prolonged periods, the probes showed areas of "local sleep" despite the animals' appearance of being awake and active.
And there were behavioral consequences to the local sleep episodes.
"When we prolonged the awake period, we saw the rats start to make mistakes," Cirelli says.
When animals were challenged to do a tricky task, such as reaching with one paw to get a sugar pellet, they began to drop the pellets or miss in reaching for them, indicating that a few neurons might have gone off line.
"This activity happened in few cells," Cirelli adds. "For instance, out of 20 neurons we monitored in one experiment, 18 stayed awake. From the other two, there were signs of sleepbrief periods of activity alternating with periods of silence."
The researchers tested only motor tasks, so they concluded from this study that neurons affected by local sleep are in the motor cortex.
More information: Local sleep in awake rats. Vyazovskiy VV, Olcese U, Hanlon EC, Nir Y, Cirelli C, Tononi G. Nature. 2011 April 28.
Provided by University of Wisconsin-Madison
- Brain responds same to acute and chronic sleep loss Aug 09, 2010 | not rated yet | 0
- Sleep: Spring cleaning for the brain? Apr 02, 2009 | not rated yet | 0
- Brain's energy restored during sleep, suggests animal study Jun 29, 2010 | not rated yet | 0
- What happens when we sleep Jan 28, 2009 | not rated yet | 0
- Brain tweak lets sleep-deprived flies stay sharp Jul 31, 2008 | not rated yet | 0
- Motion perception revisited: High Phi effect challenges established motion perception assumptions Apr 23, 2013 | 3 / 5 (2) | 2
- Anything you can do I can do better: Neuromolecular foundations of the superiority illusion (Update) Apr 02, 2013 | 4.5 / 5 (11) | 5
- The visual system as economist: Neural resource allocation in visual adaptation Mar 30, 2013 | 5 / 5 (2) | 9
- Separate lives: Neuronal and organismal lifespans decoupled Mar 27, 2013 | 4.9 / 5 (8) | 0
- Sizing things up: The evolutionary neurobiology of scale invariance Feb 28, 2013 | 4.8 / 5 (10) | 14
Why is zone 1 in liver more prone to ischemic injury?
May 23, 2013 Hi, Is it because around central vein, there is only deoxygenated blood from the vein where as in the periphery there is hepatic artery. Also why...
How can there be villous adenoma in colon, if there are no villi there
May 22, 2013 As title suggest. Thanks :smile:
How can there be a term called "intestinal metaplasia" of stomach
May 21, 2013 Hello everyone, Ok Stomach's normal epithelium is simple columnar, now in intestinal type of adenocarcinoma of stomach it undergoes "intestinal...
Pressure-volume curve: Elastic Recoil Pressure don't make sense
May 18, 2013 From pressure-volume curve of the lung and chest wall (attached photo), I don't understand why would the elastic recoil pressure of the lung is...
If you became brain-dead, would you want them to pull the plug?
May 17, 2013 I'd want the rest of me to stay alive. Sure it's a lousy way to live but it beats being all-the-way dead. Maybe if I make it 20 years they'll...
MRI bill question
May 15, 2013 Dear PFers, The hospital gave us a $12k bill for one MRI (head with contrast). The people I talked to at the hospital tell me that they do not...
- More from Physics Forums - Medical Sciences
More news stories
New research presented today shows that formation of new neurons in the hippocampus - a brain region known for its importance in learning and remembering - could cause forgetting of old memories by causing a reorganization ...
Neuroscience 3 hours ago | 5 / 5 (2) | 0
How can healthy people who hear voices help schizophrenics? Finding the answer for this is at the centre of research conducted at the University of Bergen.
Neuroscience 4 hours ago | 3 / 5 (1) | 2
One of the major frontiers of modern science is a comprehensive understanding of the human brain and its functions to guide the development of new technologies in information and communication. In a major announcement for ...
Neuroscience 4 hours ago | not rated yet | 0
(Medical Xpress)—Regulating the distribution of power in neurons is done by a system that makes the national electric grid look simple by comparison. Each neuron has several thousand mitochondria confined ...
Neuroscience 19 hours ago | 4.9 / 5 (9) | 0 |
(Medical Xpress)—The human brain is able to identify individuals' voices by comparing them against an internal 'average voice' prototype, according to neuroscientists.
Neuroscience 23 hours ago | 3 / 5 (2) | 2 |
(HealthDay)—We've all seen them: the surfers who race to the beach when a hurricane hits, the guy who decides to ride out the storm in his overmatched boat, the tornado chasers who fearlessly steer their ...
36 minutes ago | not rated yet | 0
(HealthDay)—New evidence-based guidelines provide guidance on medical and surgical methods for second-trimester abortion and management of associated complications, according to a practice bulletin published ...
16 minutes ago | not rated yet | 0
(HealthDay)—More than one in four of those eligible for new premium assistance tax credits under the Affordable Care Act (ACA) do not have a checking account and will not be able to receive premiums from ...
6 minutes ago | not rated yet | 0
Cancer cells spread and grow by avoiding detection and destruction by the immune system. Stimulation of the immune system can help to eliminate cancer cells; however, there are many factors that cause the immune system to ...
55 minutes ago | not rated yet | 0
In recent years, microRNAs (miRNAs) and other non-coding RNAs are small molecules that help control the expression of specific proteins. In recent years they have emerged as disease biomarkers. miRNA profiles have been used ...
53 minutes ago | not rated yet | 0