Rapid blood pressure drops in middle age linked to dementia in old age

Temporary episodes of dizziness or light-headedness when standing could reduce blood flow to the brain with lasting impacts

March 10, 2017

Science Daily/Johns Hopkins University Bloomberg School of Public Health
Middle-aged people who experience temporary blood pressure drops that often cause dizziness upon standing up may be at an increased risk of developing cognitive decline and dementia 20 years later.

The findings, being presented March 10 at the American Heart Association's EPI|LIFESTYLE 2017 Scientific Sessions in Portland, Ore., suggest that these temporary episodes -- known as orthostatic hypotension -- may cause lasting damage, possibly because they reduce needed blood flow to the brain. Previous research has suggested a connection between orthostatic hypotension and cognitive decline in older people, but this appears to be the first to look at long-term associations.

"Even though these episodes are fleeting, they may have impacts that are long lasting," says study leader Andreea Rawlings, PhD, MS, a post-doctoral researcher in the Department of Epidemiology at the Bloomberg School. "We found that those people who suffered from orthostatic hypotension in middle age were 40 percent more likely to develop dementia than those who did not. It's a significant finding and we need to better understand just what is happening."

An estimated four million to five million Americans currently have dementia and, as the population ages, that number is only expected to grow. There currently is no treatment and no cure for the condition.

For the study, the researchers analyzed data from the Atherosclerosis Risk in Communities (ARIC) cohort, a study of 15,792 residents in four communities in the United States, who were between the ages of 45 and 64 when the study began in 1987. For this study, they focused on the 11,503 participants at visit one who had no history of coronary heart disease or stroke. After 20 minutes lying down, researchers took the participants' blood pressure upon standing. Orthostatic hypotension was defined as a drop of 20 mmHg or more in systolic blood pressure or 10 mmHg or more in diastolic blood pressure. Roughly six percent of participants, or 703 people, met the definition.

These participants, who were on average 54 years old upon enrolling in the study, continued to be followed over the next 20 or more years. People with orthostatic hypotension at the first visit were 40 percent more likely to develop dementia than those who did not have it. They had 15 percent more cognitive decline.

Rawlings says it is not possible to tease out for certain whether the orthostatic hypotension was an indicator of some other underlying disease or whether the drop in blood pressure itself is the cause, though it is likely that the reduction in blood flow to the brain, however temporary, could have lasting consequences.

It also wasn't clear, she says, whether these participants had repeated problems with orthostatic hypotension over many years or whether they had just a brief episode of orthostatic hypotension at the original enrollment visit, as patients were not retested over time.

"Identifying risk factors for cognitive decline and dementia is important for understanding disease progression, and being able to identify those most at risk gives us possible strategies for prevention and intervention," Rawlings says. "This is one of those factors worth more investigation."

Science Daily/SOURCE :https://www.sciencedaily.com/releases/2017/03/170310132631.htm

The way the brain processes speech could serve as a predictor of early dementia

March 15, 2017

Science Daily/Baycrest Centre for Geriatric Care
Early dementia is typically associated with memory and thinking problems, but older adults should also be vigilant about hearing and communication problems, suggest new recent findings.

Within older adults who scored below the normal benchmark on a dementia screening test, but have no noticeable communication problems, scientists have discovered a new potential predictor of early dementia through abnormal functionality in regions of the brain that process speech (the brainstem and auditory cortex).

These brain regions are thought to be more resilient to Alzheimer's. However, this discovery demonstrates changes occur early in the brain's conversion of speech sound into understandable words. This finding could be the first sign of decline in brain function related to communication that presents itself before individuals become aware of these problems.

Their research technique of measuring electrical brain activity using an electroencephalogram (EEG) in these brain regions also predicted mild cognitive impairment (MCI), a condition that is likely to develop into Alzheimer's, with 80 per cent accuracy. This test could be developed into a cost-effective and objective diagnostic assessment for older adults.

The study, published online in the Journal of Neuroscience prior to print publication, looked at older adults with no known history of neurological or psychiatric illnesses with similar hearing acuity.

The brain activity within the brainstem of these older adults demonstrated abnormally large speech sound processing within seven to 10 milliseconds of the signal hitting the ear, which could be a sign of greater communication problems in the future.

"This opens a new door in identifying biological markers for dementia since we might consider using the brain's processing of speech sounds as a new way to detect the disease earlier," says Dr. Claude Alain, the study's senior author and senior scientist at Baycrest's Rotman Research Institute (RRI) and professor at the University of Toronto's psychology department.

"Losing the ability to communicate is devastating and this finding could lead to the development of targeted treatments or interventions to maintain this capability and slow progression of the disease."

The study involved 23 older adults between the ages of 52 and 86. Participants were separated into two groups based on their results on a dementia screening test, the Montreal Cognitive Assessment (MoCA). Researchers measured brain activity in the brainstem while participants were watching a video. They measured brain activity in the auditory cortex while participants were identifying vowel sounds. Statistical methods were used to combine both sets of brain activity to predict MCI.

"When we hear a sound, the normal aging brain keeps the sound in check during processing, but those with MCI have lost this inhibition and it was as if the flood gates were open since their neural response to the same sounds were over-exaggerated," says Dr. Gavin Bidelman, first author on the study, a former RRI post-doctoral fellow and assistant professor at the University of Memphis. "This functional biomarker could help identify people who should be monitored more closely for their risk of developing dementia."

The next steps involve studying whether those individuals who already have dementia or convert early from MCI to dementia also demonstrate these same changes in brain activity when they hear speech.

Research for this study was conducted with support from the Grammy Foundation, the Canadian Institutes of Health Research, the FedEx Institute of Technology and the Center for Technologies and Research in Alzheimer's Care, which supported the staff and equipment needed to conduct the study.

With additional funds, researchers could explore developing a portable, reliable and easy-to-use alternate diagnostic test for MCI that incorporates the body's different senses.

"MCI is known to cause changes in different senses, such as vision or touch," says Dr. Alain. "If we could incorporate these changes into a wireless EEG test, we could combine all this information and develop a better biomarker. One day, doctors could administer a short, 10-minute assessment and instantly provide results."

"This could offer a new diagnostic assessment that tests a person's cognitive abilities, such as their ability to communicate, and objectively measure physiological changes in the brain that reflect early signs of dementia," says Dr. Bidelman.

Science Daily/SOURCE :https://www.sciencedaily.com/releases/2017/03/170315125552.htm

Daily consumption of tea may protect the elderly from cognitive decline

March 16, 2017
Science Daily/National University of Singapore
Tea drinking reduces the risk of cognitive impairment in older persons by 50 per cent and as much as 86 per cent for those who are genetically at risk of Alzheimer's, new research suggests.
https://images.sciencedaily.com/2017/03/170316093412_1_540x360.jpg
NUS researchers found that regular consumption of tea brewed from tea leaves reduces elderly persons' risk of cognitive decline.
Credit: © Serhiy Shullye / Fotolia

A cup of tea a day can keep dementia away, and this is especially so for those who are genetically predisposed to the debilitating disease, according to a recent study led by Assistant Professor Feng Lei from the Department of Psychological Medicine at National University of Singapore's (NUS) Yong Loo Lin School of Medicine.

The longitudinal study involving 957 Chinese seniors aged 55 years or older has found that regular consumption of tea lowers the risk of cognitive decline in the elderly by 50 per cent, while APOE e4 gene carriers who are genetically at risk of developing Alzheimer's disease may experience a reduction in cognitive impairment risk by as much as 86 per cent.

The research team also discovered that the neuroprotective role of tea consumption on cognitive function is not limited to a particular type of tea -- so long as the tea is brewed from tea leaves, such as green, black or oolong tea.

"While the study was conducted on Chinese elderly, the results could apply to other races as well. Our findings have important implications for dementia prevention. Despite high quality drug trials, effective pharmacological therapy for neurocognitive disorders such as dementia remains elusive and current prevention strategies are far from satisfactory. Tea is one of the most widely consumed beverages in the world. The data from our study suggests that a simple and inexpensive lifestyle measure such as daily tea drinking can reduce a person's risk of developing neurocognitive disorders in late life," explained Asst Prof Feng.

He added, "Based on current knowledge, this long term benefit of tea consumption is due to the bioactive compounds in tea leaves, such as catechins, theaflavins, thearubigins and L-theanine. These compounds exhibit anti-inflammatory and antioxidant potential and other bioactive properties that may protect the brain from vascular damage and neurodegeneration. Our understanding of the detailed biological mechanisms is still very limited so we do need more research to find out definitive answers."

In this study, tea consumption information were collected from the participants, who are community-living elderly, from 2003 to 2005. At regular intervals of two years, these seniors were assessed on their cognitive function using standardised tools until 2010. Information on lifestyles, medical conditions, physical and social activities were also collected. Those potential confounding factors were carefully controlled in statistical models to ensure the robustness of the findings.

The research team published their findings in scientific journal The Journal of Nutrition, Health & Aging in December 2016.

Future Research

Asst Prof Feng and his team are planning to embark on further studies to better understand the impact of Asian diet on cognitive health in aging. They are also keen to investigate the effects of the bioactive compounds in tea and test them more rigorously through the assessment of their biological markers and by conducting randomised controlled trials or studies that assign participants into experimental groups or control groups randomly to eliminate biased results.

Science Daily/SOURCE :https://www.sciencedaily.com/releases/2017/03/170316093412.htm

One in four elderly Australian women has dementia

At least a quarter of Australian women over 70 will develop dementia according to study

March 17, 2017

Science Daily/University of Queensland
At least a quarter of Australian women over 70 will develop dementia according to researchers. Australian policymakers previously had to rely on dementia rates from international studies, or extrapolated from clinical assessments made on small groups of people. The researchers used a technique borrowed from ecologists to provide an up-to-date estimate for dementia in the Australian population

The researchers used a new technique to provide an up-to-date estimate for dementia in the Australian population. Dr Michael Waller from the UQ School of Public Health said the nation's population was aging, but there was conflicting information being presented.

"On one hand we expect the number of women living with dementia to increase, but on the other hand there is international research suggesting rates might be decreasing," Dr Waller said.

"Having an up-to-date, local estimate of dementia rates is important so that policy makers and the health care and aged care industries can meet the needs of older Australians.

"There's no national registry for dementia, so Australian policy makers have had to rely on dementia rates from international studies, or extrapolated from clinical assessments made on small groups of people.

"We needed a new approach so we used a method ecologists call 'capture-recapture'.

"Where an ecologist works with animals, we work with data.

"So instead of capturing, tagging, releasing and then recapturing animals to estimate a population size we are applying the same technique to health data to estimate the number of cases.

"The prevalence of dementia is often underestimated and this technique allows us to compare different data sources and estimate the number of cases that may have been missed."

The researchers looked at data from 12,000 Australian women born between 1921 and 1926 who participated in the Women's Health Australia study (also known as the Australian Longitudinal Study on Women's Health).

For the past 20 years participants answered detailed surveys on their lifestyle, activities, and physical and mental health.

Survey data was linked to aged care assessments, the National Death Index, the Pharmaceutical Benefits Scheme, and hospital admissions data to find any instance where the women participating in the study were diagnosed with dementia by a doctor.

"Previously, an elderly participant with dementia would have just dropped out of the survey, but by linking to additional health records we can find out what happened to them and their contribution isn't lost," Dr Waller said.

"The women in the study have been very loyal over the years and I think that they, and their families, would appreciate that their contribution to women's health research will continue despite their diagnosis."

Science Daily/SOURCE :https://www.sciencedaily.com/releases/2017/03/170317082500.htm

Better learning through zinc?

Zinc regulates the storage and release of neurotransmitters

March 21, 2017

Science Daily/Wiley
Zinc is a vital micronutrient involved in many cellular processes: For example, in learning and memory processes, it plays a role that is not yet understood. By using nanoelectrochemical measurements, researchers have made progress toward understanding by demonstrating that zinc influences the release of messenger molecules. Zinc changes the number of messenger molecules stored in vesicles and the dynamics of their release from the cell.

When signals are transmitted by synapses, messenger molecules (neurotransmitters) are released from storage chambers (synaptic vesicles) into the synaptic cleft, where they are "recognized" by neighboring nerve cells. This release is based on exocytosis: The vesicle docks at the cell membrane, opens at the point of contact, releases part of its contents to the outside, closes, and separates from the plasma membrane so it can be refilled.

A team led by Andrew G. Ewing at Gothenburg University, Sweden, used carbon fiber electrodes with nanotips to study the influence of zinc on these processes. They carried out measurements on PC12 cells that release the neurotransmitter dopamine when stimulated by a high potassium concentration, analogous to nerve cells. "By applying an electrode tip to the surface of the cell, we can follow the opening of an individual vesicle and compute the number of molecules released," says Ewing. In contrast, if the tip of the electrode is inserted into the cell, the vesicles in the cytoplasm stick to the electrode and release their full contents. Says Ewing: "The current transients allow us to determine how many transmitter molecules are contained in individual vesicles directly in the cytoplasm of the living cells."

After treatment with zinc, the total number of neurotransmitters contained in vesicles was reduced, on average by 27%. However, the amount of transmitter released upon stimulation remained constant. Analysis of the current transients provided an explanation of this apparent contradiction. According to Ewing, "Zinc changes the dynamics of the release. Before and after the opening of the vesicle a pore forms at the point of contact with the plasma membrane. After treatment with zinc, the pore closes more slowly than usual. The vesicle thus stays open longer and releases 92 % of its transmitter molecules to the outside -- instead of only 66 % without the zinc."

In order to investigate this phenomenon more closely, the cells were stripped down layer by layer from the outside in and were analyzed by mass spectrometry. The researchers found one zinc species near the cell membrane and a second in the interior of the cell. "The former is capable of binding to protein kinase C, an enzyme that binds to the membrane to regulate the speed of exocytosis. The zinc species inside the cell could slow down the transport protein that loads the dopamine into the vesicles," suggests Ewing. "Our results finally provide a connection between zinc and the regulation of neurotransmitter release. This could be important for the formation and storage of memories."

Science Daily/SOURCE :https://www.sciencedaily.com/releases/2017/03/170321110326.htm

Rosemary aroma can aid children's working memory

Exposure to the aroma of rosemary essential oil can significantly enhance working memory in children

May 2, 2017

Science Daily/British Psychological Society
Exposure to the aroma of rosemary essential oil can significantly enhance working memory in children.

This is one the findings of a study presented today, Thursday 4 May 2017, by Dr Mark Moss and Victoria Earle of Northumbria University at the British Psychological Society Annual Conference in Brighton.

Dr Mark Moss said: "Our previous study demonstrated the aroma of rosemary essential oil could enhance cognition in healthy adults. Knowing how important working memory is in academic achievement we wanted to see if similar effects could be found in school age children in classroom settings."

A total of 40 children aged 10 to 11 took part in a class based test on different mental tasks. Children were randomly assigned to a room that had either rosemary oil diffused in it for ten minutes or a room with no scent.

The children were tested individually, seated at the table opposite the researcher. After introducing herself to the child the researcher said: "You are here to play some memory games. Please don't be nervous but try the best you can to remember what I ask you to."

Analysis revealed that the children in the aroma room received significantly higher scores than the non-scented room. The test to recall words demonstrated the greatest different in scores.

Dr Moss said: "Why and how rosemary has this effect is still up for debate. It could be that aromas affect electrical activity in the brain or that pharmacologically active compounds can be absorbed when adults are exposed.

"We do know that poor working memory is related to poor academic performance and these findings offers a possible cost effective and simple intervention to improve academic performance in children. The time is ripe for large-scale trials of aroma application in education settings."

Science Daily/SOURCE :https://www.sciencedaily.com/releases/2017/05/170502204545.htm

Exercise study offers hope in fight against Alzheimer's

Walking intervention improved neural connectivity in older adults with MCI

May 3, 2017

Science Daily/University of Maryland
A new study adds more information about how physical activity impacts brain physiology and offers hope that it may be possible to reestablish some protective neuronal connections. Researchers explored how a 12-week walking intervention with older adults affected functionality of a brain region known to show declines in people suffering from mild cognitive impairment or Alzheimer's disease.
https://images.sciencedaily.com/2017/05/170503213532_1_540x360.jpg
The brain's posterior cingulate cortex (PCC)/precuneus region is a hub of neuronal networks which integrates and disperses signals. A loss of connectivity to this hub is associated with memory loss and amyloid accumulation, both signs of MCI and Alzheimer's.
Credit: J. Carson Smith

Could the initiation of a simple walking exercise program help older adults to reverse declines in key brain regions? A new study led by University of Maryland School of Public Health researchers adds more information about how physical activity impacts brain physiology and offers hope that it may be possible to reestablish some protective neuronal connections. Dr. J. Carson Smith, associate professor of kinesiology, and colleagues explored how a 12-week walking intervention with older adults, ages 60-88, affected functionality of a brain region known to show declines in people suffering from mild cognitive impairment (MCI) or Alzheimer's disease.

"The brain's posterior cingulate cortex (PCC)/precuneus region is a hub of neuronal networks which integrates and disperses signals," explains Dr. J. Carson Smith, senior author of the paper published in the Journal of Alzheimer's Disease and director of the Exercise for Brain Health Laboratory. "We know that a loss of connectivity to this hub is associated with memory loss and amyloid accumulation, both signs of MCI and Alzheimer's."

For this reason, reduced connectivity to the PCC/precuneus region is seen as a potential biomarker to detect cognitive impairment even before symptoms of MCI or AD may appear. It is also a potential target to test the effectiveness of interventions such as exercise to improve brain function in those exhibiting symptoms of MCI.

Dr. Smith's research team recruited two groups -- one with 16 healthy elders and another with 16 elders diagnosed with mild cognitive impairment to participate in an exercise intervention that included walking for 30 minutes, four times a week (at 50-60 % of heart rate reserve) for three months.

Before and after the exercise intervention, participants in both groups underwent fMRI brain scans to assess functional connectivity between multiple brain regions and the PCC/precuneus. After completing the intervention, both groups showed improved ability to remember a list of words; however only the MCI group showed increased connectivity to the PCC/precuneus hub, which was evident in 10 regions spanning the frontal, parietal, temporal and insular lobes, and the cerebellum.

"These findings suggest that the protective effects of exercise training on cognition may be realized by the brain re-establishing communication and connections among the brain's so-called default mode network, which may possibly increase the capacity to compensate for the neural pathology associated with Alzheimer's disease," said Dr. Smith.

While it is unclear yet whether the effects of exercise training can delay further cognitive decline in patients diagnosed with MCI, the neural network connectivity changes documented in this study provide hope that exercise training may stimulate brain plasticity and restore communication between brain regions that may have been lost through Alzheimer's disease. The specificity of these effects in the MCI group further suggest that exercise may be particularly useful in those who have already experienced mild memory loss. Future studies planned by Dr. Smith's team aim to include exercise control conditions, and to incorporate exercise combined with cognitive engagement, among healthy older adults who are at increased risk for Alzheimer's disease.

Science Daily/SOURCE :https://www.sciencedaily.com/releases/2017/05/170503213532.htm

Cannabis reverses aging processes in the brain

Researchers restore the memory performance of Methuselah mice to a juvenile stage

May 8, 2017
Science Daily/University of Bonn
Memory performance decreases with increasing age. Cannabis can reverse these ageing processes in the brain. This was shown in mice by scientists at the University of Bonn with their colleagues at The Hebrew University of Jerusalem (Israel). Old animals were able to regress to the state of two-month-old mice with a prolonged low-dose treatment with a cannabis active ingredient. This opens up new options, for instance, when it comes to treating dementia.

https://images.sciencedaily.com/2017/05/170508112400_1_540x360.jpg
Prof. Dr. Andreas Zimmer (left) and the North Rhine-Westphalia science minister Svenja Schulze (centre) in the lab of the Institute of Molecular Psychiatry at University of Bonn.
Credit: © Photo: Volker Lannert/Uni Bonn

Like any other organ, our brain ages. As a result, cognitive ability also decreases with increasing age. This can be noticed, for instance, in that it becomes more difficult to learn new things or devote attention to several things at the same time. This process is normal, but can also promote dementia. Researchers have long been looking for ways to slow down or even reverse this process.

Scientists at the University of Bonn and The Hebrew University of Jerusalem (Israel) have now achieved this in mice. These animals have a relatively short life expectancy in nature and display pronounced cognitive deficits even at twelve months of age. The researchers administered a small quantity of THC, the active ingredient in the hemp plant (cannabis), to mice aged two, twelve and 18 months over a period of four weeks.

Afterwards, they tested learning capacity and memory performance in the animals -- including, for instance, orientation skills and the recognition of other mice. Mice who were only given a placebo displayed natural age-dependent learning and memory losses. In contrast, the cognitive functions of the animals treated with cannabis were just as good as the two-month-old control animals. "The treatment completely reversed the loss of performance in the old animals," reported Prof. Andreas Zimmer from the Institute of Molecular Psychiatry at the University of Bonn and member of the Cluster of Excellence ImmunoSensation.

Years of meticulous research

This treatment success is the result of years of meticulous research. First of all, the scientists discovered that the brain ages much faster when mice do not possess any functional receptors for THC. These cannabinoid 1 (CB1) receptors are proteins to which the substances dock and thus trigger a signal chain. CB1 is also the reason for the intoxicating effect of THC in cannabis products, such as hashish or marihuana, which accumulate at the receptor. THC imitates the effect of cannabinoids produced naturally in the body, which fulfil important functions in the brain. "With increasing age, the quantity of the cannabinoids naturally formed in the brain reduces," says Prof. Zimmer. "When the activity of the cannabinoid system declines, we find rapid ageing in the brain."

To discover precisely what effect the THC treatment has in old mice, the researchers examined the brain tissue and gene activity of the treated mice. The findings were surprising: the molecular signature no longer corresponded to that of old animals, but was instead very similar to that of young animals. The number of links between the nerve cells in the brain also increased again, which is an important prerequisite for learning ability. "It looked as though the THC treatment turned back the molecular clock," says Zimmer.
 

Next step: clinical trial on humans

A low dose of the administered THC was chosen so that there was no intoxicating effect in the mice. Cannabis products are already permitted as medications, for instance as pain relief. As a next step, the researchers want to conduct a clinical trial to investigate whether THC also reverses ageing processes in the brain in humans and can increase cognitive ability.

The North Rhine-Westphalia science minister Svenja Schulze appeared thrilled by the study: "The promotion of knowledge-led research is indispensable, as it is the breeding ground for all matters relating to application. Although there is a long path from mice to humans, I feel extremely positive about the prospect that THC could be used to treat dementia, for instance."
Science Daily/SOURCE :https://www.sciencedaily.com/releases/2017/05/170508112400.htm

Deep sleep maintains the learning efficiency of the brain

May 23, 2017
Science Daily/University of Zurich
For the first time, researchers have demonstrated the causal context of why deep sleep is important to the learning efficiency of the human brain. They have developed a new, noninvasive method for modulating deep sleep in humans in a targeted region of the brain.

Most people know from their own experience that just a single sleepless night can lead to difficulty in mastering mental tasks the next day. Researchers assume that deep sleep is essential for maintaining the learning efficiency of the human brain in the long term. While we are awake, we constantly receive impressions from our environment, whereby numerous connections between the nerve cells -- so-called synapses -- are excited and intensified at times. The excitation of the synapses does not normalize again until we fall asleep. Without a recovery phase, many synapses remain maximally excited, which means that changes in the system are no longer possible: Learning efficiency is blocked.

Causal connection between deep sleep and learning efficiency

The connection between deep sleep and learning efficiency has long been known and proven. Now, researchers at the University of Zurich (UZH) and the Swiss Federal Institute of Technology (ETH) in Zurich have been able to demonstrate a causal connection within the human brain for the first time. Reto Huber, professor at the University Children's Hospital Zurich and of Child and Adolescent Psychiatry at UZH, and Nicole Wenderoth, professor in the Department of Health Sciences and Technology at the ETH Zurich, have succeeded in manipulating the deep sleep of test subjects in targeted areas. "We have developed a method that lets us reduce the sleep depth in a certain part of the brain and therefore prove the causal connection between deep sleep and learning efficiency," says Reto Huber.

Subjective sleep quality was not impaired

In the two-part experiment with six women and seven men, the test subjects had to master three different motoric tasks. The concrete assignment was to learn various sequences of finger movements throughout the day. At night, the brain activity of the test subjects during sleep was monitored by EEG. While the test subjects were able to sleep without disturbance after the learning phase on the first day, their sleep was manipulated in a targeted manner on the second day of the experiment -- using acoustic stimulation during the deep sleep phase. To do so, the researchers localized precisely that part of the brain responsible for learning the abovementioned finger movements, i.e., for the control of motor skills (motor cortex). The test subjects were not aware of this manipulation; to them, the sleep quality of both experimental phases was comparable on the following day.

Deep sleep disturbances impair learning efficiency

In a second step, researchers tested how the manipulation of deep sleep affected the motoric learning tasks on the following day. Here, they observed how the learning and performance curves of the test subjects changed over the course of the experiment. As expected, the participants were particularly able to learn the motoric task well in the morning. As the day went on, however, the rate of mistakes rose. After sleep, the learning efficiency considerably improved again. This was not the case after the night with the manipulated sleep phase. Here, clear performance losses and difficulties in learning the finger movements were revealed. Learning efficiency was similarly as weak as on the evening of the first day of the experiment. Through the manipulation of the motor cortex, the excitability of the corresponding synapses was not reduced during sleep. "In the strongly excited region of the brain, learning efficiency was saturated and could no longer be changed, which inhibited the learning of motor skills," Nicole Wenderoth explains.

In a controlled experiment with the same task assignment, researchers manipulated another region of the brain during sleep. In this case, however, this manipulation had no effect on the learning efficiency of the test subjects.

Use in clinical studies planned

The newly gained knowledge is an important step in researching human sleep. The objective of the scientists is to use this knowledge in clinical studies. "Many diseases manifest in sleep as well, such as epilepsy," Reto Huber explains. "Using the new method, we hope to be able to manipulate those specific brain regions that are directly connected with the disease." This could help improve the condition of affected patients.

Science Daily/SOURCE :https://www.sciencedaily.com/releases/2017/05/170523083345.htm