Scientists uncover secrets of sleep effect on tasks

Sleep is well-known to help us better understand what we have learned. But now, researchers believe they have discovered exactly how sleep helps our brains to better learn specific motor tasks, such as typing or playing the piano.

The study, published in the Journal of Neuroscience, is the first to use three different brain scans in order to determine changes in particular brainwaves and the exact location of changed brain activity in specific motor learning subjects.

Researchers carried out an analysis of 15 subjects who volunteered for motor learning experiments, which involved a series of finger-tapping tasks.

For the first 3 nights, the participants slept at whatever time they wanted to. During this period, their brains were scanned using magnetoencephalography (MEG). This measured oscillations in the brain - rhythmic neural activity in the central nervous system - as well as polysomnography (PSG), which is tracking of the sleep phase.

The study authors say that by the end of the 3 nights, they had good baseline measurements of brain activity, and the participants had become used to sleeping in their surroundings.

Finger tapping tasks

The participants were then required to carry out a series of finger-tapping tasks on their "non-dominant" hand, in order to make it harder to learn.

Nine of the participants then slept for 3 hours, while the other six stayed awake. All participants were then scanned again with MEG and PSG.

One hour later, all participants were asked to perform the finger-tapping task. The results of this experiment showed that those who slept performed the task faster and more accurately compared with those who stayed awake.

Each participant was then scanned using magnetic resonance imaging (MRI) in order to see where the MEG oscillations they observed earlier were located in each individual's brain.

The findings revealed five different oscillations over eight different brain regions - four on each side of the brain.

The researchers expected the most significant activity to take place in the M1 region of the brain - the area responsible for motor control.

However, significant changes were instead discovered in the SMA (supplementary motor area) - a region in the top-middle of the brain.

The researchers then used caps of EEG sensors to further monitor brainwave changes in the participants. They found that the brainwave changes occurred during a specific phase of sleep called "slow-wave" sleep.

The study showed that two specific brainwave oscillations were identified in the SMA that play a part in the "reorganization" the brain carries out during sleep, in order to encourage motor learning.

"Delta" oscillations appeared to control changes in the connectivity of the SMA, while "fast-sigma" oscillations seemed to be related to changes in the SMA itself.

Further studies to incorporate visual tasks

These findings support the two criteria set at the beginning of the study, the researchers say. The delta and fast-sigma oscillations changed substantially after the subjects were trained in the finger-tapping tasks, and the strength of that change was linked to how much the participant's performance improved on each task.

The study authors say they have already started a new study to further understand how the brain consolidates the learning of visual tasks. They add that they would like to see whether similar frequency bands would be uncovered along with a similar organization of brain areas.

Written by Honor Whiteman

Copyright: Medical News Today

Not to be reproduced without permission of Medical News Today

• Additional


• References


• Citations

A step toward better targets for anxiety treatments

Anxiety disorders, which include post-traumatic stress disorder, social phobias and obsessive-compulsive disorder, affect 40 million American adults in a given year. Currently available treatments, such as antianxiety drugs, are not always effective and have unwanted side effects. To develop better treatments, a more specific understanding of the brain circuits that produce anxiety is necessary, says Kay Tye, an assistant professor of brain and cognitive sciences and member of MIT's Picower Institute for Learning and Memory...

New interaction discovered between bitter and sweet in fruit flies has implications for control of insects that spread disease

Fruit flies have a lot to teach us about the complexity of food. Like these tiny little creatures, most animals are attracted to sugar but are deterred from eating it when bitter compounds are added. A new study conducted by UC Santa Barbara's Craig Montell, Duggan Professor of Neuroscience in the Department of Molecular, Cellular and Developmental Biology, explains a breakthrough in understanding how sensory input impacts fruit flies' decisions about sweet taste. The findings were published in the journal Neuron...

DNA from our mothers 'influences aging process'

Scientists say that the process through which we age is determined not only by the changes we go through in our lifetime, but also by the genes we get from our mothers, according to a study published in the journal Nature.

Researchers from Karolinska Institute and the Max Planck Institute for Biology of Aging, say that the aging process appears to be very dependent on the power plant of each cell in the body - the mitochondrion.

The mitochondrion is located within the cell and is responsible for producing the cell's supply of Adenosine 5'-triphosphate (ATP) - a source of chemical energy.

Nils-Göran Larsson, professor at the Karolinska Institute and principal investigator at the Max Planck Institute for Biology of Aging, explains:

"The mitochondria contains their own DNA, which changes more than the DNA in the nucleus, and this has a significant impact on the aging process."

He adds: "Many mutations in the mitochondria gradually disable the cell's energy production."

The researchers generated a series of inbred mice in order to study the role of mitochondrial mutations in aging. They add that mice tend to transmit low levels of DNA mutations through a germ line.

Mitochondrial DNA (mDNA) damage can build up over a person's lifetime, according to the researchers. But this latest study has found that mitochondrial DNA damage can actually be passed on from our mothers.

Mutated DNA 'speeds up aging process'

Using MRI scanning, the scientists were able to detect levels of mutated DNA in the mitochondria of the inbred mice, which sped up their aging process.

Prof. Larsson says:

"Surprisingly, we also show that our mother's mitochondrial DNA seems to influence our own aging. If we inherit mDNA with mutations from our mother, we age more quickly."

The researchers say they are, as of yet, unaware of a way mitochondria DNA damage can be affected through lifestyle intervention.

But they add that the study also showed how even low levels of passed on mutated mitochondria DNA can have developmental effects and lead to brain deformities.

"Our findings can shed more light on the aging process and prove that the mitochondria play a key part in aging. They also show that it is important to reduce the number of mutations," adds Prof. Larsson.

Dr. Barry Hoffer, of the Department of Neurosurgery at University Hospitals Case Medical Center and Case Western Reserve University School of Medicine, notes that the findings also call for the development of potential treatments that target mitochondrial function influencing aging.

"There are various dietary manipulations and drugs that can up-regulate mitochondrial function and/or reduce mitochondrial toxicity. An example would be antioxidants. This mouse model would be a 'platform' to test these drugs or diets," he adds.

The study authors say that further research will be conducted on mice, as well as fruit flies, to determine whether lifespan can be increased by reducing the number of mutations.

Written by Honor Whiteman

Copyright: Medical News Today

Not to be reproduced without permission of Medical News Today

• Additional


• References


• Citations

New findings from South Africa lead researchers to call for worldwide recording of smoking in death registries

Researchers have called for official death registries in all countries to record whether the dead person was a smoker, in a research Article published in The Lancet. New analyses of nearly half a million death records in South Africa - the first, and so far the only, country to record smoking on death registration forms - show that the death rate from tobacco is more than twice as great in the coloured (mixed ancestry) as in the white population...

Some primates protected from Ebola, even after disease symptoms appear

Scientists have successfully treated the deadly Ebola virus in infected animals following onset of disease symptoms, according to a report published online in Science Translational Medicine. The results show promise for developing therapies against the virus, which causes hemorrhagic fever with human case fatality rates as high as 90 percent. According to first author James Pettitt of the U.S...

Surprise finding may change how virulent, painful infections are viewed

The pain of invasive skin infections caused by methicillin-resistant Staphylococcus aureus, and possibly other serious, painful infections, appear to be induced by the invading bacteria themselves, and not by the body's immune response as previously thought, report scientists at Boston Children's Hospital. What's more, their research demonstrates that once the pain neurons "sense" the bacteria, they suppress the immune system, potentially helping the bacteria become more virulent...