Wednesday, May 24, 2017

Researchers aim to explore role of physical activity on aging trajectories of the brain

Most people know that regular exercise can keep a body looking and feeling young.

What about the brain?

"There has been a wealth of evidence from past studies that physical activity has beneficial effects on neurocognitive functions, such as memory and regulatory control," says Mark Peterson, Ph.D., M.S., FACSM, assistant professor of physical medicine and rehabilitation at Michigan Medicine. "Essentially, those studies show that the physical activity alters the brain's aging trajectories to preserve cognitive health."

Peterson and colleagues were recently awarded a two-year grant from the University of Michigan's Exercise & Sport Science Initiative to further examine the role physical activity plays on the brain. The grant is one of four recently awarded by the U-M initiative to study physical activity.

A shortage of comprehensive analyses propelled the new effort.

"Those previous studies did not examine the effects in a large cohort," Peterson says. "We're hoping this study fills that knowledge gap and can validate and extend the previous claims."

Peterson and his U-M colleagues in psychiatry, Chandra Sripada, M.D., Ph.D., and computer science, Jenna Wiens, Ph.D., will obtain and study the cohort and data from the United Kingdom Biobank.

"The U.K. Biobank is the world's largest prospective epidemiological study," Peterson says. "It gathers extensive questionnaires and physical and cognitive measures from 500,000 participants."

"We'll be incorporating deep-learning techniques to predict brain age from raw neuroimaging, and will examine the independent effects of objectively measured physical activity on brain age and cognitive function in the cohort," he adds.

Peterson, also a member of the U-M Global Research, Education and Collaboration in Health and Institute for Healthcare Policy and Innovation, spoke more about the study.

What made you decide to research this topic?

Peterson: There is a wealth of evidence that in middle-age and older individuals, physical activity has beneficial effects on neurocognitive functions (working memory, declarative memory, attention, etc.).

It has been conjectured that physical activity produces these effects by altering typical aging trajectories of critical brain circuits that underlie major cognitive functions. However, at this time, there have been no rigorous, large-scale studies to examine the effects of objectively measured physical activity on aging trajectories of the human brain.

What will be your focus?

Peterson: We expect to better understand the role of physical activity participation and dosage on deviations in brain health and cognitive function. It is now known that distinct brain circuits associated with specific neurocognitive functions exhibit distinct trajectories of change during aging.

Thus, we will generate maps of neurotypical change in order to assess how physical activity influences an individual's position along the expected aging trajectories. To generate these maps of neurotypical change, we will apply deep-learning methodologies.

How will your work differ from prior research efforts?

Peterson: Previous studies have used machine learning to predict brain age in various disease processes (e.g., Alzheimer's). However, this work will be the first ever to use deep-learning algorithms to better understand deviations in brain age by physical activity and functional profiles in otherwise healthy middle-aged adults.

Moreover, we will go substantially beyond previous studies in multiple ways:

  • The inclusion of participants from the world's largest epidemiologic study
  • Physical activity will be measured objectively (and not just by self-report)
  • Utilization of multimodal imaging (not just imaging of brain volume) 
  • Examination of circuit-specific aging trajectories 
  • Employment of advanced deep-learning methods for constructing brain age trajectories 
  • Analyzing complex relationships between physical activity, brain aging and cognitive functioning to gain evidence about potential causal pathways

What are you hoping to accomplish?

Peterson: Our proposed study is poised to decisively answer two critical unanswered questions: What is the effect of physical activity on circuit-specific brain aging, and does this effect mediate the effect of physical activity on improved cognitive functioning?

We anticipate that this work will lead to subsequent cross-disciplinary collaboration within U-M to secure federal funds for prospectively studying the effects of exercise for physical and cognitive health preservation or improvements in adults with and without deficits.

Who might benefit most from this research?

Peterson: This work is poised to inform public health and clinical audiences regarding the benefits of exercise and physical activity on brain health. Therefore, we expect that our findings will support and bolster the movement for integrating recommendations for exercise in clinical care.

Cambridge company ARM could restore limb movement with brain implants

ARM looking to help people who have suffered from a stroke or spinal cord injury.

ARM computer chips are found in over half the world's mobile devices.

It could help those with debilitating conditions like Parkinson’s and Alzheimer’s – and even enable those with paralysis to move again.

Cambridge technology giant ARM is working with an American engineering research centre to develop brain-implantable chips to tackle neurodegenerative diseases and help people who have suffered from a stroke or spinal cord injury.

The company has signed an agreement with the Center for Sensorimotor Neural Engineering (CSNE), based at the University of Washington, which wants to use its understanding of how the brain processes information to design implantable devices that can restore sensation and limb function, and even augment the brain’s natural healing power.

The aim of the 10-year project is to design a system-on-a-chip (SoC) for bi-directional brain-computer interfaces (BBCI). The implant will be designed to take neural signals representing movements that a person with a neurological condition or paralysis wants to make and direct them to a stimulator implanted in the spinal cord, enabling those movements to be carried out.

Further advances could enable the system to send information in the other direction, allowing the person to feel what their hand is touching, for example.

The approach could be used to enable those with artificial limbs to get feedback from them – so they could feel how tightly they are holding a loved one’s hand or how hot their cup of coffee is, for example.

And temporary implants could help individuals recover from strokes.

Dr Scott Ransom, the CSNE’s director of industry relations and innovation, said: “We are very excited to be collaborating with a company like ARM.

“ARM’s strong expertise in power-efficient microprocessors complements the CSNE’s work in computational neuroscience and brain-computer interfacing, and we expect the partnership to lead to advances in not only medical technology but other applications as well, such as consumer electronics.”

The system will decode signals in the brain and digitise them so they can be processed. But brain-implantable chips need to be very small and capable. Among the challenges is the power efficiency required and the heat generated.

ARM said: “Our industry-proven ARM Cortex-M0 processor, the smallest ARM processor available, will contribute to this very important area of research by being an integral part of the CSNE’s brain-implantable SoC.

“The project is a natural fit for ARM and our vision of improving lives around the globe by shaping a smarter, happier and healthier world with technology.

“Our ongoing goal of increasing the power-efficiency of ARM products aligns with CSNE’s advanced research work in developing low-power, efficient and implantable neural devices for medical applications.”

It is thought use of such a system could even help to coax brain neurons to rewire in ways that will help the brain recover from stroke.

While the concept sounds like science fiction, there have been some steps towards it already.

In March, researchers, including a team at Case Western Reserve University in Cleveland, Ohio, became the first to restore brain-controlled hand and arm motion in a person with complete paralysis.

Bill Kochevar, who was injured in a cycling accident, used thoughts to send messages from implants in his brain to 36 electrodes in his arm and hand, enabling him to feed himself.


Elon Musk has revealed that he is the founder and CEO of a startup seeking to create cerebral implants that will turn computers into a direct extension of our brains.

Have you ever wished you could add extra memory to your brain? Elon Musk may be able to help you with that.

Musk heads the company best known for making Tesla, the industry-leading electric car. He is also the CEO of SpaceX, which is building rockets so that humans can live on Mars. Now Musk has revealed that he is the founder and chief executive of Neuralink, a startup seeking to create cerebral implants that will turn computers into a direct extension of our brains and thus enhance our intelligence and memory.

Musk’s various projects have a single overarching aim: to safeguard the future of our species. Electric cars improve our chances of preventing dangerous levels of global warming. A permanent settlement on Mars would reduce the risk of climate change – or a nuclear war, bioterrorism, or asteroid collision – wiping out our species.

Neuralink serves this goal, too, because Musk is among those who believe that to build a machine smarter than yourself is, as Nick Bostrom, the author of Superintelligence, puts it, “a basic Darwinian error.” Yet, given rapid progress on artificial intelligence, and the multiple incentives for making computers even smarter, Musk sees no way of preventing that from happening. His favoured strategy to save us from being eliminated by super-intelligent machines is, therefore, to hook us into computers, so that we become as clever as state-of-the-art artificial intelligence, however intelligent that may be.

There is nothing new about people having electronic devices implanted in their bodies. The artificial cardiac pacemaker has been in use for nearly 60 years. Since 1998, scientists have been implanting devices in the brains of people who are paralysed, enabling them to move a cursor on a screen with their thoughts, or in more advanced versions, to move an artificial hand that can grasp things.

Such devices don’t extend our abilities beyond those of a normal healthy person. The artist Neil Harbisson, however, has an antenna implanted in his skull that enables him to hear frequencies corresponding not only to colours we can see – Harbisson has an extreme form of colorblindness – but also to infrared and ultraviolet light, which are invisible to us. Harbisson claims that he is a cyborg, that is, an organism with technologically enhanced capacities.

To move from these useful but limited devices to the kind of brain-machine interactions that Musk is seeking would require major scientific breakthroughs. Most of the research on brain implants uses nonhuman animals, and the decades of harm inflicted on monkeys and other animals make it ethically dubious.

In any case, for Musk’s plan to succeed, experimenting on humans as well as animals will be unavoidable. Incurably disabled or terminally ill patients may volunteer to participate in medical research that offers them hope where otherwise there would be none. Neuralink will begin with research designed to assist such patients, but to achieve its grand aim, it will need to move beyond them.

In the United States, Europe, and most other countries with advanced biomedical research, strict regulations on the use of human subjects would make it extremely difficult to get permission to carry out experiments aimed at enhancing our cognitive abilities by linking our brains to computers. US regulations drove Phil Kennedy, a pioneer in the use of computers to enable paralysed patients to communicate by thought alone, to have electrodes implanted in his own brain in order to make further scientific progress. Even then, he had to go to Belize, in Central America, to find a surgeon willing to perform the operation. In the United Kingdom, cyborg advocate Kevin Warwick and his wife had data arrays implanted in their arms to show that direct communication between the nervous systems of separate human beings is possible.

Musk has suggested that the regulations governing the use of human subjects in research could change. That may take some time. Meanwhile, freewheeling enthusiasts are going ahead anyway. Tim Cannon doesn’t have the scientific or medical qualifications of Phil Kennedy or Kevin Warwick, but that hasn’t stopped him from co-founding a Pittsburgh company that implants bionic devices, often after he has first tried them out on himself. His attitude is, as he said at an event billed as “The world’s first cyborg-fair,” held in Düsseldorf in 2015, “Let’s just do it and really go for it.”

People at the Düsseldorf cyborg-fair had magnets, radio frequency identification chips, and other devices implanted in their fingers or arms. The surgery is often carried out by tattooists and sometimes veterinarians because qualified physicians and surgeons are reluctant to operate on healthy people.

Are the doctors right? Should healthy people be discouraged, if not prevented, from implanting devices in themselves?

Warwick says that scientific research has benefited from what the cyborg enthusiasts have done. “It’s their call,” he says, and that seems right – so long as people are properly informed of the risks and freely consent to take them. If we do not prevent people from smoking, or from climbing K2 in winter, it isn’t easy to see why we should be more paternalistic when people volunteer to contribute to advances in science. Doing so may add meaning to their lives, and if Musk is right, it could ultimately save us all.

_Written by Agata Sagan and Peter Singer, Professor, Princeton University

Sleep position affects the brain’s ability to clear waste: Study

Getting a good night’s sleep is important to all of us. If we don’t get it, our entire day ahead will feel like a grind. We all know that sleep can be a restorative practice, but it is also a cerebral one. While we sleep, our brains are continually working. It regulates our breathing, heart rate, and even induces weird dreams. What we don’t realize is that while sleeping, the brain is relocating our experiences and memories, only keeping what’s important.

This process may be facilitated by the way you sleep. New research actually suggests that the position you sleep plays an important role in removing brain waste.

It is estimated that about 63 percent of Americans sleep on their side, 14 percent on their back, and 16 percent on their stomach. Sleep experts recommend to just stick with what you are comfortable with, barring any recommended position for the sake of health.

Sleeping on your side is good for your brain

However, a new study states that sleeping on your side helps the brain clear chemical waste. Researchers used a magnetic resonance imaging (MRI) and special dynamic contrast agents (to help the brain appear clearly). They viewed a structure called the glymphatic pathway, which is involved in filtering cerebral spinal fluid (CSF). This pathway allows for chemical and waste product build up to be removed. This includes the built-up beta-amyloid and tau proteins, associated with Alzheimer’s and Parkinson’s disease.

“It is interesting that the lateral [side] sleep position is already the most popular in humans and most animals—even in the wild—and it appears that we have adapted the lateral sleep position to most efficiently clear our brain of the metabolic waste products that build up while we are awake,” said Maiken Nedergaard, who was involved in the study.

They put rodent models to sleep while monitoring their glymphatic pathways were monitored.

“The analysis showed us consistently that glymphatic transport was most efficient in the lateral position when compared to the supine or prone positions. Because of this finding, we propose that the body posture and sleep quality should be considered when standardizing future diagnostic imaging procedures to assess CSF-ISF transport in humans,” said co-author Dr. Helene Benveniste.

6 Ways Exercise Benefits The Body And Brain

Though some people actually love physical activity and look forward to it, for many of us, exercising is a mighty drag. Exercise has also had an added PR problem in recent years: A growing body of evidence has shown that it’s not all that good for weight loss, which was probably many people’s reason for doing it in the first place. It may help with weight a little, especially for maintenance, but by and large, if you want to drop pounds, the most effective way is to eat less, not necessarily to exercise more. That said, research in recent years has also illustrated quite persuasively what exercise is good for—and it is actually good for a number of things, including some very profound things, like reducing dementia risk. Here’s what science tells us we should probably keep exercising for, even though we may not love every minute of it.

Reduces inflammation (and cancer and diabetes and…)

This one is a big one, since inflammation may be an underlying cause of a wide range of diseases and disorders in both body and brain. Exercise is known to reduce a number of inflammatory markers, like c-reactive protein (CRP) and internleukin-6 (IL-6), which are linked to a number of diseases. “The thing about exercise is that it has a multitude of effects on many different organs and systems,” says Suzi Hong, who studies exercise and immune system activation at the UC San Diego School of Medicine, “so often it is difficult to pinpoint which organ systems are influenced and which ones are not with which specific effects for what conditions… The anti-inflammatory effects of exercise are likely one of the underpinnings of its effects against cardiovascular disease, diabetes, certain cancers, neurodegenerative conditions and more.”

A new study from her lab shows that a 20-minute moderate workout has measurable effects on the immune system: Participants were asked to walk or jog on a treadmill, depending on their fitness level. They measured levels of TNF, an inflammatory marker, before and after the exercise, and found that there was a 5% reduction in the number of immune cells that produced the marker.

Previous studies from her lab have also shown that the exercise is linked to changes in the secretion of stress hormones like epinephrine (a.k.a. adrenaline) and norepinephrine. “Our work has shown that each moderate, relatively short exercise bout exerts regulatory/suppression effects over inflammatory activities of immune cells," says Hong, "and in order to maximize this ‘benefit,’ repeated and regular exercise is recommended. In fact, we have also found that higher physical fitness is associated with better regulation of inflammatory activities of immune cells through stress hormones even among obese individuals.”

A workout once in a blue moon won’t do it, she says: you really have to exercise regularly, since hormone levels largely return to baseline after you exercise. That said, there’s an effect that accrues over time, which is what you want to harness by being active at least a few times a week. “What I’d caution readers is not to view our results as ‘one 20-minute moderate exercise will be a cure for all inflammatory conditions,’” says Hong. “These significant immune effects we observed occurred immediately with one bout of exercise, and likely will occur each time one exercises. So every time you exercise you’d see this effect, which will be cumulative over time.”

Reduces the risk of heart attack and stroke

Although the cardiovascular effects of exercise are partly related to inflammation, they still deserve their own category. Exercise is one of the best-illustrated things we can do for our hearts, and this includes markers like blood pressure and cholesterol, in addition the physical structure of the heart itself, and blood vessel function. Studies have suggested that 30 minutes per day is good enough to keep the heart in shape, while others have suggested we do more than this to get a real effect. Some have found that light activity is even enough to help the heart, but not all research confirms this, so it’s a little hard to tell how low levels of activity affect heart health over the long term. Additionally, too much exercise has also been shown to be stressful to the heart. So all this is to say that there’s probably a sweet spot somewhere in the middle for optimal cardiovascular health.

“Slows” aging

Exercise has long been correlated with a longer life, but it’s only recently started to become clear why this might be. Studies, like a new one in the journal Preventive Medicine which found that exercise is linked to longer caps at the ends of chromosomes, have helped flesh this out a bit more. These caps, called telomeres, naturally shorten as we age, with each cell division. People who live a long time have telomeres that are in better shape than those who don’t—but there’s a lot we can do to affect the rate at which they shorten over the years. The team behind the new study looked at data from CDC's National Health and Nutrition Examination Survey, and found that for people who exercised regularly, their telomeres were 140 base pairs longer on average than sedentary people's. Which correlates to being years “younger” than their sedentary peers.

“Telomeres are a good index of cellular aging,” says study author Larry Tucker of Brigham Young University. “In short, because of lifestyle differences, some adults are older biologically than their chronological age, while others are younger. Given the same chronological age, adults who engage in high levels of physical activity have nine years’ less cell aging than sedentary individuals. That is substantial and meaningful.”

Another study this month, from Mayo Clinic, found that exercise in older people who were formerly sedentary had at least as strong an impact as in it did in young people—at least in the kinds of genes that were expressed. The study also found that these changes were much more robust in response to interval training than to weight lifting or moderate exercise. Which may mean that for some things, the type of exercise we chose matters.

It triggers the growth of new brain cells

This is a particularly cool one. Neuroscientists used to believe the brain was the only organ incapable of growing new cells—which partly makes sense, since we need our brains to be relatively stable over time, to keep our memories intact and to keep us us. But in recent years, it’s become clear that the brain, too, can grow new neurons, in a process called neurogenesis. And what seems to spur the growth of new neurons, perhaps above other activities, is aerobic exercise. (Other things, like meditation and antidepressant medication, have also been shown to trigger brain new cell growth.) The area of the brain that seems most capable of growing new cells is the hippocampus, the seat of learning and memory. It's also the area that’s known to “shrink” in depression, and particularly in dementia—so the fact that we may have some control over its health is exciting.

Helps treat depression, and prevent it

Despite the fact that depression is now the leading cause of disability across the globe, there are disturbingly few effective treatments. And the ones that are effective for a person often take time, and trial and error, to find. Interestingly, exercise has been shown to be as effective as other forms of treatment for some types of depression.

Studies have consistently shown that physical activity can help treat depression, and on the flipside, that low activity levels are a big risk factor for it. The antidepressant effect of exercise seems to be moderated in part through serotonin, the brain chemical that’s targeted with some antidepressants, and in part through bone-derived neurotrophic factor (BDNF). And this goes back to the generation of new cells mentioned earlier—exercise, though various mechanisms, seems to make the brain more plastic and more capable of growing new cells.

Unfortunately, when people are depressed, exercise can be the last thing one wants to do, which can be a barrier to treatment. But it seems to make a big difference in depression risk, so building up from even a few minutes a day may help. And if you’re not depressed, exercise might prevent depression from developing in the first place.

Reduces dementia risk

This may be the most worthwhile reason for exercising there is. Studies have shown how people who exercise are at a significantly reduced risk of developing dementia like Alzheimer’s disease. And even for people who start exercising relatively late in life, brain volume can actually increase over time, as can scores on memory tests, compared to people who don’t exercise (their brains shrunk over time, which is normal part of aging).

“Being active as we age can play a role in cognitive function, and reduce the risk of disease such as dementia and Alzheimer's,” says Amanda Paluch, a postdoctoral researcher at the Northwestern University Feinberg School of Medicine. “Research has explored several mechanisms, finding that exercise can increase synaptic plasticity and strength of nerve impulses in the brain, and have a positive effect on the hippocampus.”

How much do you really need?

Exercise has been shown to reduce not only the risk of diseases, but also the mortality risk that they confer. Researchers have pointed out that if people exercised more, this change could reduce a huge number of deaths worldwide—for instance, they’ve calculated that over half of all deaths from cancer might be prevented with regular exercise.

But again, it's not so clear how much we need. The usual recommendations are 150 minutes/week of moderate activity, but as mentioned, that part is still up for debate. Some research suggests we need more than this to reap the benefits, while other suggests that every little bit helps. “Most research shows there is no lower threshold for health benefits,” says Paluch, “meaning that some activity is better than none and even small increases in activity will bring substantial benefits. Physical activity has the fantastic ability to act through multiple physiologic pathways in the body, making it a great bang for your buck.”

It may be best to start small and build up from there. Finding what feels right—a place that's challenging but not painful—may be the best gauge of all.

Our brains predict events in fast-forward

What happens when you look up and see a ball headed toward you? Without even thinking about it, you flinch. That might be because our brains are constantly living our lives in fast-forward, playing out the action in our head before it happens.

Humans have to navigate, and respond to, an environment that is always changing. Our brain compensates for this by constantly making predictions about what’s going to happen, says Mattias Ekman, a researcher at Radboud University Nijmegen in the Netherlands. We’ve known this for a while, but these predictions are usually associative. An example: if you see a hamburger, your brain might predict that there will be fries nearby. In a study published today in the journal Nature Communications, Ekman and other scientists focused instead on how the brain predicts motion. So they used brain scans to track what happened as participants observed a moving dot.

First, 29 volunteers looked at a white dot the size of a ping-pong ball. The dot went from left to right and then reversed directions. The volunteers watched the dot for about five minutes while scientists scanned their brains with ultra-fast fMRI. This way, the researchers know what pattern of brain activity was activated in the visual cortex while they watched the dot.

After these five minutes, the researchers showed only the beginning of the sequence to the volunteers. Here, the scans showed that the brain “autocompletes” the full sequence — and it does it at twice the rate of the actual event. So if a dot took two seconds to go across the screen, the brain predicted the entire sequence in one second. “You’re actually already trying to predict what’s going to happen,” says Ekman. “These predictions are hypothetical, so in a way you’re trying to generate new memories that match the future.”

In fact, “twice as fast as real-time” might not be the actual number because it’s limited by the brain scans, notes Ekman. An electrode placed directly in the brain might find that the rate of compression is even faster. (It’s worth noting here that the brain scan they did use, called fMRI, can sometimes be unreliable. It measures brain activity by recording how blood oxygen levels change, not by directly measuring what’s happening. And sometimes there are false positives, like when one study showed brain activity in a dead salmon.)

The study is an interesting blend of research on visual perception and memory, says neuroscientist Arjen Alink, who was not involved in the study. “The results are quite striking, because I would have expected a more subtle result,” he says. “But the effect is not minor.”

Of course, events in the real world are a lot more complex than a dot moving across the screen, and that’s the biggest limitation of the study. “It’s difficult to transfer this into the real world because there objects aren’t deterministic and, for example, a car can take a turn,” says Ekman. “So then the question is, is the brain still able to do these more complex predictions?” The next step is to figure out how well the results hold up in real-world scenarios, and what exactly is going on when someone says to look up because a ball is headed our way.

The brain starts to eat itself after chronic sleep deprivation

Sleep loss in mice sends the brain’s immune cells into overdrive. This might be helpful in the short term, but could increase the risk of dementia in the long run

Missing sleep can cause long-term harm

Burning the midnight oil may well burn out your brain. The brain cells that destroy and digest worn-out cells and debris go into overdrive in mice that are chronically sleep-deprived.

In the short term, this might be beneficial – clearing potentially harmful debris and rebuilding worn circuitry might protect healthy brain connections. But it may cause harm in the long term, and could explain why a chronic lack of sleep puts people at risk of Alzheimer’s disease and other neurological disorders, says Michele Bellesi of the Marche Polytechnic University in Italy.

Bellesi reached this conclusion after studying the effects of sleep deprivation in mice. His team compared the brains of mice that had either been allowed to sleep for as long as they wanted or had been kept awake for a further eight hours. Another group of mice were kept awake for five days in a row – mimicking the effects of chronic sleep loss.

The team specifically looked at glial cells, which form the brain’s housekeeping system. Earlier research had found that a gene that regulates the activity of these cells is more active after a period of sleep deprivation.

One type of glial cell, called an astrocyte, prunes unnecessary synapses in the brain to remodel its wiring. Another type, called a microglial cell, prowls the brain for damaged cells and debris.

Bellisi’s team found that after an undisturbed sleep, astrocytes appeared to be active in around 6 per cent of the synapses in the brains of the well-rested mice. But astrocytes seemed to be more active in sleep-deprived mice – those that had lost eight hours of sleep showed astrocyte activity in around 8 per cent of their synapses, while the cells were active in 13.5 per cent of the synapses of the chronically sleep-deprived animals.

This suggests that sleep loss can trigger astrocytes to start breaking down more of the brain’s connections and their debris. “We show for the first time that portions of synapses are literally eaten by astrocytes because of sleep loss,” says Bellesi.

For all we know, this may be a good thing. Much of the remodelling was of the largest synapses, which are more mature and used more intensively. “They are like old pieces of furniture, and so probably need more attention and cleaning,” says Bellesi.

But the team also found that microglial cells were more active after chronic sleep deprivation.

This is a more worrying find, says Bellesi; excessive microglial activity has been linked to a range of brain disorders. “We already know that sustained microglial activation has been observed in Alzheimer’s and other forms of neurodegeneration,” he says.

The finding could explain why a lack of sleep seems to make people more vulnerable to developing such dementias, says Agnès Nadjar of the University of Bordeaux in France.

It’s not yet clear whether getting more sleep could protect the brain or rescue it from the effects of a few sleepless nights. The researchers plan to investigate how long the effects of sleep deprivation last.

Why exercise protects your brain against dementia

Time and time again, research shows that regular exercise will lengthen your life expectancy and keep you fitter, happier and healthier as you age.

Another reason to make exercise a priority is the promising amount of research that points to it as a way to fight dementia and keep our minds sharp well into old age.

“Converging evidence suggests exercise benefits brain function and cognition across the mammalian lifespan, which may translate into reduced risk for Alzheimer’s

More research is needed to understand exactly why this is, but it seems largely to do with the hippocampus, part of the brain which is vital for creating new memories.

The hippocampus shrinks in the final years of our lives, and is the part of the brain first and worst affected by Alzheimer’s. But studies have found the hippocampus responds quickly and positively to exercise.

A 2011 study of 120 elderly people published in scientific journal PNAS found that aerobic exercise grew the size of the anterior hippocampus, and led to improvements in memory.

The researchers say hippocampal volume increased by 2 percent, reversing age-related loss in volume by at least one to two years.

A 2011 study found that children who took part in aerobic fitness regularly were better at “relational binding” (like recalling the name of a person you met recently and where you met them) than less active kids.

A study of adult rats found that running increased the growth of new neurons in the hippocampus compared with their sedentary rat counterparts.

One study on mice found the neural benefits of physical exercise lasted up to two weeks after the session.

And another study of 1740 men and women aged 65 or older with no cognitive impairment at the beginning of the research found that six years later, incidence of Alzheimer’s was higher in those that exercised less than three times per week than those who exercised more frequently.

Aside from the hippocampus research, exercise will also reduce your chances of developing dementia because it decreases some key dementia risk factors including heart disease, stroke, high blood pressure, type 2 diabetes and obesity.

Art Kramer, director of the Beckman Institute for Advanced Science and Technology and a Professor of Psychology at the University of Illinois in the US, is about to begin a multimillion dollar study into this area of research.

“Exercise doesn’t just maintain cognitive ability, but actually improves it,” he told Coach. “In randomised control trials in sedentary older adults you find they improve memory, problem solving and a variety of other things when exercise is introduced.”

Kramer said while it’s exciting for older members of the population, parents should encourage their children to set up consistent exercise habits for life.

“Some of the research will focus on working with kids in after school exercise programs, because kids are becoming increasingly sedentary, increasingly obese.”

Alzheimer’s Australia recommends at least 30 minutes of aerobic exercise, such as brisk walking, dancing, jogging, bicycling or swimming, on most days of the week.