Wednesday, February 8, 2012

Study to understand how brain processes information in competitive settings

Researchers have found a way to study how our brains assess the behavior - and likely future actions - of others during competitive social interactions. Their study, described in a paper in the Proceedings of the National Academy of Sciences, is the first to use a computational approach to tease out differing patterns of brain activity during these interactions, the researchers report.
"When players compete against each other in a game, they try to make a mental model of the other person's intentions, what they're going to do and how they're going to play, so they can play strategically against them," said University of Illinois postdoctoral researcher Kyle Mathewson, who conducted the study as a doctoral student in the Beckman Institute with graduate student Lusha Zhu and economics professor and Beckman affiliate Ming Hsu, who now is at the University of California, Berkeley. "We were interested in how this process happens in the brain."
Previous studies have tended to consider only how one learns from the consequences of one's own actions, called reinforcement learning, Mathewson said. These studies have found heightened activity in the basal ganglia, a set of brain structures known to be involved in the control of muscle movements, goals and learning. Many of these structures signal via the neurotransmitter dopamine.
"That's been pretty well studied and it's been figured out that dopamine seems to carry the signal for learning about the outcome of our own actions," Mathewson said. "But how we learn from the actions of other people wasn't very well characterized."
Researchers call this type of learning "belief learning."
To better understand how the brain processes information in a competitive setting, the researchers used functional magnetic resonance imaging (fMRI) to track activity in the brains of participants while they played a competitive game, called a Patent Race, against other players. The goal of the game was to invest more than one's opponent in each round to win a prize (a patent worth considerably more than the amount wagered), while minimizing one's own losses (the amount wagered in each trial was lost). The fMRI tracked activity at the moment the player learned the outcome of the trial and how much his or her opponent had wagered.
A computational model evaluated the players' strategies and the outcomes of the trials to map the brain regions involved in each type of learning.
"Both types of learning were tracked by activity in the ventral striatum, which is part of the basal ganglia," Mathewson said. "That's traditionally known to be involved in reinforcement learning, so we were a little bit surprised to see that belief learning also was represented in that area."
Belief learning also spurred activity in the rostral anterior cingulate, a structure deep in the front of the brain. This region is known to be involved in error processing, regret and "learning with a more social and emotional flavor," Mathewson said.
The findings offer new insight into the workings of the brain as it is engaged in strategic thinking, Hsu said, and may aid the understanding of neuropsychiatric illnesses that undermine those processes.
"There are a number of mental disorders that affect the brain circuits implicated in our study," Hsu said. "These include schizophrenia, depression and Parkinson's disease. They all affect these dopaminergic regions in the frontal and striatal brain areas. So to the degree that we can better understand these ubiquitous social functions in strategic settings, it may help us understand how to characterize and, eventually, treat the social deficits that are symptoms of these diseases."

Scientists image working brain cell in real time

LONDON: Scientists have, for the very first time, recorded live yet detailed images of the nerve cells in the brain of a mouse.

Stefan Hell's team at the Max Planck Institute in Gottingen, Germany, used STED microscopy to explore the most intricate cerebral structures to unravel how it functions.

Captured in the previously impossible resolution of less than 70 nanometres (a nanometre is a billionth of a metre), these images have made the ultra minute structures visible which allow nerve cells to communicate with one another.

This application of STED microscopy opens up numerous new possibilities for neuroscientists to decode fundamental processes in the brain, according to a Max Planck statement.

Every moment our brain processes an enormous amount of data, with each of its 100 billion nerve cells (neurons) chatting with thousands of neighbouring nerve cells.

The entire data exchange takes place via contact sites - the synapses. Only if neurons communicate via synapses and at the right place can the brain master its complex tasks -- playing a difficult piece of piano, learning to juggle, etc.

We can learn most about these important contact sites in the brain by observing them at work. When and where do new synapses form and why do they disappear elsewhere? This is not easy to determine, since details in living nerve cells can only be observed with optical microscopes.

Due to the peculiarities of light, however, structures located closer together than 200 nanometres appear as a single blurred spot. The STED microscopy developed by Stefan Hell and his team is a groundbreaking method devised to surpass this resolution limit.

They use a simple trick: Closely-positioned elements are kept dark under a special laser beam so that they emit fluorescence sequentially one after the other, rather than simultaneously, and can therefore be distinguished.

Using this technique, Hell's team has been able to increase the resolution by approximately tenfold compared to conventional optical microscopes.

Thanks to STED microscopy, the first real-time video clips from a neuron's interior have demonstrated how tiny transmitter vesicles (assembly of molecules) migrate within the long nerve cell endings.

Brain mechanisms link foods to rising obesity rates

An editorial authored by University of Cincinnati (UC) diabetes researchers to be published in the Feb. 7, 2012, issue of the journal Cell Metabolism sheds light on the biological factors contributing to rising rates of obesity and discusses strategies to reduce body weight.

According to the U.S. Centers for Disease Control, about one-third of U.S. adults are obese, a number that continues to climb.
"While we don't usually think of it this way, body weight is regulated. How much we weigh is influenced by a number of biological systems, and this is part of what makes it so hard for people to lose weight and keep it off," says Randy Seeley, PhD, Donald C. Harrison Endowed Chair, director of the Cincinnati Diabetes and Obesity Center and author on the paper along with Karen Ryan, PhD, an assistant professor in endocrinology, diabetes and metabolism at UC.
"To understand the obesity epidemic, we must figure out how our environment alters these biological systems to encourage weight gain."
Seeley says a big part of the environment that encourages weight gain is the availability and consumption of calorically dense, high-fat foods—in particular, what we eat can alter the brain regions that regulate body weight.
"Leptin is a key hormone that is secreted from fat tissue, or adipose tissue, and its main function is to inhibit appetite," Seeley says. "Via a number of molecular mechanisms, eating a high-fat diet reduces the actions of leptin in the brain. This miscommunication can lead to increased food intake and weight gain."
"Evolutionary speaking, we are designed to want to eat foods that are high in fat and gain weight because it made it easier to survive times when food was not available," he continues. "However, that is no longer a real concern since food is almost always available, but we still have a biological desire to eat these calorically dense foods. So, how do we intervene and change this drive?"
Seeley says there are several key points in successful therapeutic interventions for the population facing social, financial and health consequences of obesity.
"The key issue is to find ways to take these biological systems that usually make it hard to lose weight and make them work for us to so that it is easier for obese individuals to lose weight," he says. "As we understand the molecular interaction between what we eat and these brain circuits that regulate our body weight, we can design interventions that reduce the body weight that our bodies defend. This will mean that people trying to lose weight would be able to work with their biology rather than trying to use will power to overcome their biology that pushes them back to their obese state. Such an endeavor will ultimately require a wide range of scientists from different fields to reduce both the human and monetary costs of the obesity epidemic."

Brain size could determine whether you are good at maintaining friendships

Researchers are suggesting that there is a link between the number of friends you have and the size of the region of the brain - known as the orbital prefrontal cortex - that is found just above the eyes. A new study shows that this brain region is bigger in people who have a larger number of friendships. Their study is published on 1 February 2012 in the journal, Proceedings of the Royal Society B.

Image: National Institutes of Health, via Wikimedia Commons
The research was carried out as part of the British Academy Centenary 'Lucy to Language' project, led by Professor Robin Dunbar of the University of Oxford in a collaboration with Dr Joanne Powell and Dr Marta Garcia-Finana at Liverpool University, Dr Penny Lewis at Manchester University and Professor Neil Roberts at Edinburgh University.

The study suggests that we need to employ a set of cognitive skills to maintain a number of friends (and the keyword is 'friends' as opposed to just the total number of people we know). These skills are described by social scientists as 'mentalising' or 'mind-reading' - a capacity to understand what another person is thinking, which is crucial to our ability to handle our complex social world, including the ability to hold conversations with one another. This study, for the first time, suggests that our competency in these skills is determined by the size of key regions of our brains (in particular, the frontal lobe).

Professor Dunbar, from the Institute of Cognitive and Evolutionary Anthropology, explained: "'Mentalising' is where one individual is able to follow a natural hierarchy involving other individuals' mind states. For example, in the play 'Othello', Shakespeare manages to keep track of five separate mental states: he intended that his audience believes that Iago wants Othello to suppose that Desdemona loves Cassio [the italics signify the different mind states]. Being able to maintain five separate individuals' mental states is the natural upper limit for most adults."

The researchers took anatomical MR images of the brains of 40 volunteers at the Magnetic Resonance and Image Analysis Research Centre at the University of Liverpool to measure the size of the prefrontal cortex, the part of the brain used in high-level thinking. Participants were asked to make a list of everyone they had had social, as opposed to professional, contact with over the previous seven days. They also took a test to determine their competency in mentalising.

Professor Robin Dunbar, said: "We found that individuals who had more friends did better on mentalising tasks and had more neural volume in the orbital frontal cortex, the part of the forebrain immediately above the eyes. Understanding this link between an individual's brain size and the number of friends they have helps us understand the mechanisms that have led to humans developing bigger brains than other primate species. The frontal lobes of the brain, in particular, have enlarged dramatically in humans over the last half million years."

Dr Joanne Powell, from the Department of Psychology, University of Liverpool, said: "Perhaps the most important finding of our study is that we have been able to show that the relationship between brain size and social network size is mediated by mentalising skills. What this tells us is that the size of your brain determines your social skills, and it is these that allow you have many friends."

Professor Dunbar said: "All the volunteers in this sample were postgraduate students of broadly similar ages with potentially similar opportunities for social activities. Of course, the amount of spare time for socialising, geography, personality and gender all influence friendship size, but we also know that at least some of these factors, notably gender, also correlate with mentalising skills. Our study finds there is a link between the ability to read how other people think and social network size."

Professor Dunbar's research was funded by the British Academy Centenary Research Project and by the British Academy Research Professorship. His research has already examined the different brain sizes of different species, but this study looks at the differences within species. Professor Dunbar published a paper last year, which found that people living near to the Poles needed larger brains for visual processing because of the dimmer light conditions.

MIT crowdsources and gamifies brain analysis

Eyewire neuron analysisThere are around 100 billion neurons in a human brain, forming up to 100 trillion synaptic interconnections. Neuroscientists believe that these synapses are the key to almost every one of your unique, identifiable features: Memories, mental disorders, and even your personality are encoded in the wiring of your brain.
Understandably, neuroscientists really want to investigate these neurons and synapses to work out how they play such a vital role in our human makeup. Unfortunately, these 100 trillion connections are crammed into a two-pound bag of soggy flesh, making analysis rather hard. At the moment we know that neurons trigger an electrical signal, and that hormones affect the speed at which signals cross between synapses, and that somehow this results in a mental image of a naked Kristen Bell from her Veronica Mars period, but that’s about it.
NeuronMIT wants to change all that by tasking thousands of people with analyzing a 0.3-millimeter slice of mouse retinal tissue. Using a new site called Eyewire, MIT will ask users to track a neuron’s path by coloring in each axon (tendril). In the future, MIT will roll out another “game” which challenges users to find the synapses. The end result will be the connectome (a tome of connections) of the mouse’s retina.
To perform this kind of analysis, MIT must slice this three-dimensional 0.3-millimeter piece of brain tissue into incredibly thin, “2D” slices using a diamond blade and a process called serial electron microscopy. The slices are so thin that a terabyte of images are created from a piece of brain that’s much smaller than the head of a pin. You now have some idea of how hard it will be to investigate and understand the human brain; we’re talking about hundreds of exabytes of imagery that would need to be analyzed.
Ultimately, though, if we could get our hands on the connectome of the human brain… Well, we would experience an enlightenment of unprecedented scale. We would understand exactly why we are the way that we are. There would be no stones left to turn.

Spanking harms kids, smoking harms brains

  • Spanking and kids: There's no upside to spanking kids, says a research review that backs up what pediatricians and other experts have been saying for years. Kids who are spanked are more likely to become depressed, anxious and aggressive in childhood and adulthood.
  • Smoking and men's brain health: Cigarettes aren't just bad for your heart and lungs -- they are bad for your brain. Middle-aged men who smoke show signs of c
    ognitive decline that would be expected in men who are ten years older, a new study finds. One possible explanation: Smokers' brains may get less vital blood, oxygen and nutrients.
  • Defining dementia: Most people now diagnosed with early stages of Alzheimer's disease would not get that label under new diagnostic criteria, a new study suggests. Instead, most would be told they have "mild cognitive impairment" -- a change that some experts worry will cause confusion for patients and families.
  • Labeling foods: Wal-Mart stores will start labeling certain store-brand foods and bins of produce as "Great for You" choices with a new green and white seal. The company is applying its own nutrition standards to decide which foods qualify.
Today's talker: Online dating is a popular and surefire way to identify lots of potential mates -- though not necessarily the love of your life. That's the conclusion of a report from psychologists who question the success claims of sites such as eHarmony, PerfectMatch and Chemistry. The scientists looked at matching systems similar to those used by the sites and concluded, as one co-author said, "there is no reason to believe that online dating improves romantic outcomes."

Cutting-edge MRI techniques for studying communication within the brain

IMAGE: Brain Connectivity is published bimonthly in print and online. For more information and to read a sample issue, visit

New Rochelle, NY, February 7, 2012—Innovative magnetic resonance imaging (MRI) techniques that can measure changes in the microstructure of the white matter likely to affect brain function and the ability of different regions of the brain to communicate are presented in an article in the groundbreaking new neuroscience journal Brain Connectivity, a bimonthly peer-reviewed publication from Mary Ann Liebert, Inc.. The article is available free online at
Brain function depends on the ability of different brain regions to communicate through signaling networks that travel along white matter tracts. Using different types and amounts of tissue staining to measure how water molecules interact with the surrounding brain tissue, researchers can quantify changes in the density, orientation, and organization of white matter. They can then use this information to generate image maps of these signaling networks, a method called tractography.
Andrew Alexander and colleagues from University of Wisconsin, Madison, describe three quantitative MRI (qMRI) techniques that are enabling the characterization of the microstructural properties of white matter: diffusion MRI, magnetization transfer imaging, and relaxometry. This approach can be used to study and compare the properties of brain tissue across populations and to shed light on mechanisms underlying aging, disease, and gender differences in brain function, for example. The authors present their findings in the article "Characterization of Cerebral White Matter Properties Using Quantitative Magnetic Resonance Imaging Stains."
"White matter is the material that provides for the wiring and connectivity between brain regions. This exciting paper describes three new methodologies to measure the integrity of white matter in normal and diseased brain. These methods show promise in multiple sclerosis, depression, aging, and human development," says Bharat Biswal, PhD, Co-Editor-in-Chief of Brain Connectivity and Associate Professor, University of Medicine and Dentistry of New Jersey.

Brain Connectivity is the journal of record for researchers and clinicians interested in all aspects of brain connectivity. The Journal is under the leadership of founding and Co-Editors-in-Chief Christopher Pawela, PhD, assistant professor at the Medical College of Wisconsin, and Bharat Biswal, PhD. The Journal publishes original peer-reviewed papers, review articles, point-counterpoint discussions on controversies in the field, and a product/technology review section. To ensure that scientific findings are rapidly disseminated, articles are published Instant Online within 72 hours of acceptance, with fully typeset, fast-track publication within 4 weeks. Complete tables of content and a sample issue may be viewed online at
Mary Ann Liebert, Inc. is a privately held, fully integrated media company known for establishing authoritative medical and biomedical peer-reviewed journals, including Journal of Neurotrauma and Therapeutic Hypothermia and Temperature Management. Its biotechnology trade magazine, Genetic Engineering & Biotechnology News (GEN), was the first in its field and is today the industry's most widely read publication worldwide. A complete list of the firm's 70 journals, newsmagazines, and books is available at our website.
Mary Ann Liebert, Inc. 140 Huguenot Street, New Rochelle, NY 10801-5215
Phone (914) 740-2100 (800) M-LIEBERT Fax (914) 740-2101

Neuroscientists link brain-wave pattern to energy consumption

Emery Brown, an MIT professor of brain and cognitive sciences and health sciences and technology, left, and ShiNung Ching, a postdoc in Brown’s lab.

New model of neuro-electric activity could help scientists better understand quiescent brain states such as coma.

Different brain states produce different waves of electrical activity, with the alert brain, relaxed brain and sleeping brain producing easily distinguishable electroencephalogram (EEG) patterns. These patterns change even more dramatically when the brain goes into certain deeply quiescent states during general anesthesia or a coma.

MIT and Harvard University researchers have now figured out how one such quiescent state, known as burst suppression, arises. The finding, reported in the online edition of the Proceedings of the National Academy of Sciences the week of Feb. 6, could help researchers better monitor other states in which burst suppression occurs. For example, it is also seen in the brains of heart attack victims who are cooled to prevent brain damage due to oxygen deprivation, and in the brains of patients deliberately placed into a medical coma to treat a traumatic brain injury or intractable seizures.

During burst suppression, the brain is quiet for up to several seconds at a time, punctuated by short bursts of activity. Emery Brown, an MIT professor of brain and cognitive sciences and health sciences and technology and an anesthesiologist at Massachusetts General Hospital, set out to study burst suppression in the anesthetized brain and other brain states in hopes of discovering a fundamental mechanism for how the pattern arises. Such knowledge could help scientists figure out how much burst suppression is needed for optimal brain protection during induced hypothermia, when this state is created deliberately.

“You might be able to develop a much more principled way to guide therapy for using burst suppression in cases of medical coma,” says Brown, senior author of the PNAS paper. “The question is, how do you know that patients are sufficiently brain-protected? Should they have one burst every second? Or one every five seconds?”

Modeling electrical activity

ShiNung Ching, a postdoc in Brown’s lab and lead author of the PNAS paper, developed a model to describe how burst suppression arises, based on the behavior of neurons in the brain. Neuron firing is controlled by the activity of channels that allow ions such as potassium and sodium to flow in and out of the cell, altering its voltage.

For each neuron, “we’re able to mathematically model the flow of ions into and out of the cell body, through the membrane,” Ching says. In this study, the team combined many neurons to create a model of a large brain network. By showing how both cooling and certain anesthetic drugs reduce the brain’s use of ATP (the cell’s energy currency), the researchers were able to generate burst-suppression patterns consistent with those actually seen in human patients.

This is the first time that reductions in metabolic activity at the neuron level have been linked to burst suppression, and suggests that the brain likely uses burst suppression to conserve vital energy during times of trauma.

“What’s really exciting about this is the idea that the metabolic regulation of cell energy stores plays a role in the observed dynamics of EEG. That’s a different way to think about the determinants of EEG,” says Nicholas Schiff, a professor of neurology and neuroscience at Weill Cornell Medical College who was not involved in this research.

The developing brain

Burst suppression is also seen in babies born prematurely. As these babies get older, their brain patterns move into the normal continuous pattern. Brown speculates that in premature infants, the brain may be protecting itself by conserving energy.

“When you’re looking at these kids develop, we can easily start to suggest ways of tracking their improvement quantitatively. So the same algorithms we use to track burst suppression in the operating room could be used to track the disappearance of burst suppression in these kids,” Brown says.

Such tracking could help doctors determine whether premature infants are moving toward normal development or have an underlying brain disorder that might otherwise go undiagnosed, Ching says.

In future studies, the researchers plan to study premature infants as well as patients whose brains are cooled and those in induced comas. Such studies could reveal just how much burst suppression is enough to protect the brain in those vulnerable situations.

Brain does math when disaster looms: Study

Math A team of Canadian and American researchers managed to figure out the calculations that specific neurons use to cause us to avoid approaching calamity..

You're just walking up the cereal aisle, looking for Fruit Loops, when you hear the clatter of impending disaster.
Some teenager has pushed his mom's grocery cart directly at you.
In the visual flash that takes place before it can crash into you legs, what goes through your mind?
It's math.
At least according to a team of Canadian and American researchers, who have mapped the visual processes the brain uses to figure out if Billy's cart of doom will leave you with a bruise.
The study, by scientists at the Montreal Neurological Institute and Hospital -- known as The Neuro -- as well as the University of Maryland, managed to figure out the calculations that specific neurons use to cause us to avoid approaching calamity.
Igniting certain regions of the brain, the calculations work out needed information -- how far away the object is, is it harmlessly moving to the right or left or is it speeding up?
Specialized neurons in the brain's visual cortex, in an area known as MST, detect motion patterns, including expansion, rotation and deformation.
The computations used in the process were previously unknown, the researchers say.
They now know how individual MST neurons function.
But don't give yourself too much credit for those lightning fast math reflexes.
"Essentially, the underlining process is very similar to what a beetle, or fly or bird goes through," says Dr. Christopher Pack, of the high alert system that kicks in when danger rushes in.
A senior author of the research, and neuroscientist at The Neuro, Pack says he doubts the calculations used have changed much since the first big-fanged creature headed toward early man.
His team found a remarkably simple computation is at the core, and it comes down to multiplication problems.
Though in your mind, as you jump out of the way of the cart, you wish you could hold up just a single digit to that kid who pushed it.

Brain cells created from patients' skin cells

Neural stem cells. Credit: Yichen Shi (Livesey Lab) University of Cambridge
Brain cells created from patients' skin cells
(Medical Xpress) -- Cambridge scientists have, for the first time, created cerebral cortex cells – those that make up the brain’s grey matter – from a small sample of human skin.  The researchers’ findings, which were funded by Alzheimer’s Research UK and the Wellcome Trust, were published today in Nature Neuroscience.

Diseases of the cerebral cortex range from developmental conditions, such as epilepsy and autism, to neurodegenerative conditions such as Alzheimer’s.  Today’s findings will enable scientists to study how the human cerebral cortex develops, how it ‘wires up’ and how that can go wrong (a common problem leading to learning disabilities).
It will also allow them to recreate brain diseases, such as Alzheimer’s, in the lab.  This will give them previously impossible insight, allowing them to both watch the diseases develop in real time and also develop and test new drugs to stop the diseases progressing.
Dr. Rick Livesey of the Gurdon Institute and Department of Biochemistry at the University of Cambridge, principal investigator of the research, said: “This approach gives us the ability to study human brain development and disease in ways that were unimaginable even five years ago.”
For their research, the scientists took skin biopsies from patients and then reprogrammed the cells from the skin samples back into stem cells.  These stem cells as well as human embryonic stem cells were then used to generate cerebral cortex cells.
Dr. Livesey added: “We are using this system to recreate Alzheimer’s disease in the lab. Alzheimer’s disease is the commonest form of dementia in the world, and dementia currently affects over 800,000 people in the UK. It’s a disease that primarily affects the type of nerve cell we’ve made in the lab, so we’ve the perfect tool to create a full, human model of the disease in the lab.”
Dr. Simon Ridley, Head of Research at Alzheimer’s Research UK, the UK’s leading dementia research charity, said: “We are really pleased to have contributed funding for this work and the results are a positive step forward. Turning stem cells into networks of fully functional nerve cells in the lab holds great promise for unravelling complex brain diseases such as Alzheimer’s.
“Dementia is the greatest medical challenge of our time – we urgently need to understand more about the condition and how to stop it. We hope these findings can move us closer towards this goal.”

British scientists want… your brain: Appeal for donors to help battle against dementia

Roy Mellor (who suffers from dementia) and his wife Susan, from Consett, County Durham, have jointly become the 200th donor at the brain bank
Roy Mellor (who suffers from dementia) and his wife Susan, from Consett, County Durham, have jointly become the 200th donor at the brain bankResearchers are calling for more people to donate their brain to science, to help in the battle against dementia.

The call comes from Newcastle University - which has just recruited its 200th brain donor - as the institution tries to drum up even more support.

The university's brain bank is part of a £2m initiative called Brains for Dementia Research, which collects tissue to help scientists defeat dementia.

Roy and Susan Mellor, from Consett, County Durham, have jointly become the 200th donor.

Mr Mellor, a retired engineer, has vascular dementia and has signed up as a dementia donor. His wife, a retired social worker, has signed up as a normal brain donor.

Mrs Mellor said: 'I think it is terrifically important that more people sign up.

Dementia is one of the most seriously underfunded diseases as far as research is concerned, and it is a massive problem.' The couple have been married for 48 years and have three children and seven grandchildren.

Mrs Mellor added: 'Roy was diagnosed with vascular dementia in May 2008. We live a very normal, ordinary life and he is aware of his condition.' 

The couple were also recently involved in setting up a Memory Cafe, a cafe for people with dementia organised by the Alzheimer's Society. Brains for Dementia Research, jointly funded by the charities

Alzheimer's Research UK and Alzheimer's Society, was set up in 2007 to address a nationwide need for brain tissue. The brain tissue it collects will allow scientists to unravel the biology of dementia and will help in the search for vital new treatments. 

Dr Chris Morris, scientific director of the Newcastle Brain Tissue Resource, said: 'It is brilliant news and we would like to say a big thank you to those who have already agreed to donate.

'We understand that brain donation is a very personal decision, which should be supported by friends and family, but we would urge more people in the region to find out about what it is and how they could get involved.

Male smokers lose brain function faster as they age

In a large, long-term study, British researchers found that while there seems to be no link between cognitive decline and smoking in women, in men, the habit is linked to swifter decline, with early dementia-like cognitive difficulties showing up as early as the age of 45. 

LONDON: Men who smoke suffer a more rapid decline in brain function as they age than their non-smoking counterparts, with their cognitive decline as rapid as someone 10 years older but who shuns tobacco, scientists said on Monday.
In a large, long-term study, British researchers found that while there seems to be no link between cognitive decline and smoking in women, in men, the habit is linked to swifter decline, with early dementia-like cognitive difficulties showing up as early as the age of 45.
The research adds to an already large body of evidence about the long-term dangers of smoking — a habit the World Health Organisation refers to as “one of the biggest public health threats the world has ever faced”.
Smoking causes lung cancer, which is often fatal, and other chronic respiratory diseases. It is also a major risk factor for cardiovascular diseases, the world’s number one killers.
“While we were aware that smoking is a risk factor for respiratory disease, cancer, and cardiovascular disease, this study shows it also has a detrimental effect on cognitive ageing and this is evident as early as 45 years,” said Severine Sabia of University College London, who led the study and published it in the Archives of General Psychiatry journal.
In an interview she said one explanation for the gender difference found in this study might be the larger amount of tobacco smoked by men, or the fact that there was a significantly lower proportion of women than men among those involved in the research.
Sabia’s team looked for possible links between smoking history and cognitive decline in the transition from midlife to old age using data from 5,099 men and 2,137 women who are involved in a large research project called the Whitehall II study, which is based on employees of the British Civil Service.
The average age of those taking part was 56 when they had their first cognitive assessment.
The study used six assessments of smoking status over 25 years and three cognitive assessments over 10 years, and found that smokers showed a cognitive decline as fast as non-smokers 10 years older than them.
“A 50 year old male smoker shows a similar cognitive decline as a 60 year old male never smoker,” Sabia explained.
She also found that men who quit smoking in the 10 years before the first cognitive testing point were still at risk of greater cognitive decline, especially in executive function – which covers various complex cognitive processes involved in achieving a particular goal.
Long-term ex-smokers, however, did not show a faster decline in their brain functions or cognitive abilities.
Sabia said more research is now needed to find out why there was a difference between men and women in this study, and to look into possible mechanisms that might link declining brain function to smoking.