Posts tagged brain
Articles and news from the latest research reports.
How the brain controls our habits
Habits are behaviors wired so deeply in our brains that we perform them automatically. This allows you to follow the same route to work every day without thinking about it, liberating your brain to ponder other things, such as what to make for dinner.
However, the brain’s executive command center does not completely relinquish control of habitual behavior. A new study from MIT neuroscientists has found that a small region of the brain’s prefrontal cortex, where most thought and planning occurs, is responsible for moment-by-moment control of which habits are switched on at a given time.
“We’ve always thought — and I still do — that the value of a habit is you don’t have to think about it. It frees up your brain to do other things,” says Institute Professor Ann Graybiel, a member of the McGovern Institute for Brain Research at MIT. “However, it doesn’t free up all of it. There’s some piece of your cortex that’s still devoted to that control.”
The new study offers hope for those trying to kick bad habits, says Graybiel, senior author of the new study, which appears this week in the Proceedings of the National Academy of Sciences. It shows that though habits may be deeply ingrained, the brain’s planning centers can shut them off. It also raises the possibility of intervening in that brain region to treat people who suffer from disorders involving overly habitual behavior, such as obsessive-compulsive disorder.
Sport Makes Middle-Aged People Smarter
High-intensity interval training makes middle-aged people not only healthier but smarter, showed a Montreal Heart Institute (MHI) study led by Dr. Anil Nigam of the MHI and University of Montreal, in collaboration with the Montreal Geriatric University Institute.
“We worked with six adults who all followed a four-month program of twice weekly interval training on stationary bicycles and twice weekly resistance training. Cognitive function, VO2max and brain oxygenation during exercise testing revealed that the participants’ cognitive functions had greatly improved thanks to the exercise,” Dr. Nigam said. VO2max is the maximum capacity of an individual’s body to transport and use oxygen during exercise. It impacts on the body’s ability to oxygenate the brain and is related to cognitive function.
“Our participants underwent a battery of cognitive, biological and physiological tests before the program began in order to determine their cognitive functions, body composition, cardiovascular risk, brain oxygenation during exercise and maximal aerobic capacity,” Dr. Nigam explained.
“After the program was finished, we discovered that their waist circumference and particularly their trunk fat mass had decreased. We also found that their VO2max, insulin sensitivity had increased significantly, in tandem with their score on the cognitive tests and the oxygenation signals in the brain during exercise,” Dr Nigam said. Insulin sensitivity is the ability of sugar to enter body tissue (mainly liver and muscle.)
Eye Movements and the Search for Biomarkers for Schizophrenia
There is a long history of research on impaired eye movements associated with schizophrenia. Using a series of simple viewing tests, researchers of a new paper in Biological Psychiatry explored the ability of these eye movement tests to distinguish people with and without the diagnosis of schizophrenia.
Using their complete dataset, they were able to develop a model that could discriminate all schizophrenia cases from healthy control subjects with an impressive 98.3% accuracy.
Drs. Philip Benson and David St. Clair, lead authors on the paper, agreed that their findings were remarkable: “It has been known for over a hundred years that individuals with psychotic illnesses have a variety of eye movement abnormalities, but until our study, using a novel battery of tests, no one thought the abnormalities were sensitive enough to be used as potential clinical diagnostic biomarkers.”
Their battery of tests included smooth pursuit, free-viewing, and gaze fixation tasks. In smooth pursuit, people with schizophrenia have well-documented deficits in the ability to track slow-moving objects smoothly with their eyes. Their eye movements tend to fall behind the moving object and then catch-up with the moving object using a rapid eye movement, called a saccade.. A picture is displayed in the free-viewing test, and where most individuals follow a typical pattern with their gaze as they scan the picture, those with schizophrenia follow an abnormal pattern. In a fixation task, the instruction is to keep a steady gaze on a single unmoving target, which tends to be difficult for individuals with schizophrenia.
As expected, the researchers found that the performance of individuals with schizophrenia was abnormal compared to the healthy volunteer group on each of the eye tests. At right is an example of the differences, with the eye tracking of a schizophrenia case in red and a healthy control in blue.
The researchers then used several methods to model the data. The accuracy of each of the created algorithms was then tested by using eye test data from another group of cases and controls. Combining all the data, one of the models achieved 98.3% accuracy.
"It is encouraging to see the high sensitivity of this model for the diagnosis of schizophrenia. It will be interesting to see the extent to which this approach enables clinical investigators to distinguish people with schizophrenia from individuals with other psychiatric disorders," commented Dr. John Krystal, Editor of Biological Psychiatry.
Benson and St Clair have already started that work, stating, “We now have exciting unpublished data showing that patterns of eye movement abnormalities are specific to different psychiatric subgroups, another key requirement for diagnostic biomarkers. The next thing we want to know is when the abnormalities are first detectable and can they be used as disease markers for early intervention studies in major mental illness?”
"We are also keen to explore how best our findings can be developed for use in routine clinical practice," they added. Typical neuropsychological assessments are time-consuming, expensive, and require highly trained individuals to administer. In comparison, these eye tests are simple, cheap, and take only minutes to conduct. This means that a predictive model with such precision could potentially be incorporated in clinics and hospitals to aid physicians by augmenting traditional symptom-based diagnostic criteria.
(Source: alphagalileo.org)
Bird-brains solve problems spontaneously
In certain situations animals can spontaneously solve problems without planning their actions, according to research from The University of Auckland’s School of Psychology.
Animals rarely solve problems spontaneously, yet certain bird species are able to rapidly gain access to food hung on the end of a long string, by repeatedly pulling and then stepping on the string. For over 400 years it has been a mystery as to how the birds spontaneously solve the “string pulling” problem.
The University of Auckland research shows that such problem solving is not created by birds first solving the problem in their heads. Rather, problem solving occurs online as the bird makes the food on the end of the string move.
“Crows and parrots have long been known to solve the string pulling problem immediately. What our new research shows is that these performances are due to the birds being able to react in the moment to the effects of their actions, rather than being able to mentally plan out their actions,” says Dr Alex Taylor, lead author on the study.
“Thus string pulling appears to be based on a different type of intelligence than we had thought. Instead of the crows using sophisticated cognitive software to model the world, it appears their neural hardware is sufficiently well connected and/or specialised for them to react to the effect of their actions immediately. This allows them to solve problems that other bird species cannot.”
The work, by Dr Taylor, Brenna Knaebe and Professor Russell Gray, titled “An end to insight? New Caledonian crows can spontaneously solve problems without planning their actions”, has been published in the Proceedings of the Royal Society B: Biological Sciences online.
Mind over machine: Use your brainwaves to control your computer
When it comes to controlling our computers, the last five years has seen incredible improvements in user interfaces including amazing touch screens and much more natural vocal recognition. Now, a Toronto company wants to take the UI to the next level — by going directly to the brain. You think it, and the Muse headband will make it happen under very limited circumstances.
InteraXon, the maker of the Muse headband, has listed it device on Indiegogo in hopes of raising $150,000 for building out a mass-produced headband that translates your mental commands into a computer action. The example they show on the site is playing a game using an iPad, where the rotation of a wooden block occurs when the user focuses on it. The user tilts the iPad to change the angle of the rotation.
The ideas behind the Muse are echoed in a project released by Chaotic Moon Studios earlier this year called the Board of Imagination, whereby a user controls a skateboard that connected to an iPad and a brainwave reader made by a different company called Emotiv. In that use case, the user’s focus is what makes the skateboard move forward.
Biofeedback-augmented video game helps children curb their anger
Often, when people talk about children and the psychological effects of playing video games, it’s nothing good – there are certainly plenty of individuals who maintain that if a child spends too much time blowing away virtual enemies, they will become more aggressive, antisocial people in the real world. A new game developed at Boston Children’s Hospital, however, is intended to do just the opposite. It helps children with anger problems to control their temper, so they’ll get along better with other people.
The game, appropriately called RAGE Control, requires the young player to shoot at enemy spaceships while sparing friendly ones. The child’s heart rate is monitored and displayed on the screen, via a sensor attached to one of their fingers. As long as they keep calm and their heart rate stays below a certain threshold, they can keep blasting at the spaceships. If they lose control and their heart rate goes too high, however, they lose the ability to shoot – the only way to regain that ability is to calm back down and lower their heart rate.
“The connections between the brain’s executive control centers and emotional centers are weak in people with severe anger problems,” said Dr. Joseph Gonzalez-Heydrich, co-creator of the game and senior investigator on the study. “However, to succeed at RAGE Control, players have to learn to use these centers at the same time to score points.”
Early Intervention Improves Social Skills and Brain Activity in Preschoolers with Autism
The Early Start Denver Model (ESDM), a comprehensive behavioral early intervention program that is appropriate for children with autism spectrum disorder (ASD) as young as 12 months, has been found to be effective in improving social skills and brain responses to social cues in a randomized controlled study published online today in the Journal of the American Academy of Child & Adolescent Psychiatry.
“So much of a toddler’s learning involves social interaction, and early intervention that promotes attention to people and social cues may pay dividends in promoting the normal development of the brain and behavior,” said Geraldine Dawson, Ph.D., Autism Speaks chief science officer and the study’s lead author. This is the first controlled study of an intensive early intervention that demonstrates both improvement of social skills and brain responses to social stimuli resulting from intensive early intervention. Given that the American Academy of Pediatrics recommends that all 18- and 24-month-old children be screened for autism, “it is vital that we have effective therapies available for young children as soon as they are diagnosed,” continued Dr. Dawson.
“This may be the first demonstration that a behavioral intervention for autism is associated with changes in brain function as well as positive changes in behavior,” said Thomas R. Insel, M.D., director of the National Institute of Mental Health. “By studying changes in the neural response to faces, Dawson and her colleagues have identified a new target and a potential biomarker that can guide treatment development.”
ESDM, which combines applied behavioral analysis (ABA) teaching methods with developmental ‘relationship-based’ approaches, was previously demonstrated to achieve significant gains in cognitive, language and daily living skills compared to children with ASD who received commonly available community interventions. On average, the preschoolers receiving ESDM for two years improved 17.5 standard score points compared to 7.0 points in the community intervention comparison group.
Stimulating brain cells with light
Introducing a light-sensitive protein in transgenic nerve cells… transplanting nerve cells into the brains of laboratory animals… inserting an optic fibre in the brain and using it to light up the nerve cells and stimulate them into releasing more dopamine to combat Parkinson’s disease… These events may sound like science fiction but they are soon to become a reality in a research laboratory at Lund University in Sweden.
For the time being, this is basic research but the long term objective is to find new ways of treating Parkinson’s disease. This increasingly common disease is caused by degeneration of the brain cells producing signal substance dopamine.
Many experiments have been conducted on both animals and humans, transplanting healthy nerve cells to make up for the lack of dopamine, but it is difficult to study what happens to the transplant.
“We don’t know how the new nerve cells behave once they have been transplanted into the brain. Do they connect to the surrounding cells as they should, and can they function normally and produce dopamine as they should? Can we use light to reinforce dopamine production? These are the issues we want to investigate with optogenetics”, says Professor Merab Kokaia.
Optogenetics allows scientists to control certain cells in the brain using light, leaving other cells unaffected. In order to do this, the relevant cells are equipped with genes for a special light-sensitive protein. The protein makes the cells react when they are illuminated with light from a thin optic fibre which is also implanted in the brain. The cells can then be “switched on” when they are illuminated.
“If we get signals as a response to light from the host brain, we know that they come from the transplanted cells since they are the only ones to carry the light-sensitive protein. This gives us a much more specific way of studying the brain’s reactions than inserting an electrode, which is the current method. With an electrode, we do not know whether the electric signals that are detected come from “new” or “old” brain cells”, explains Merab Kokaia.
The work will be conducted on laboratory rats modelling Parkinson’s disease. The transplanted cells will be derived from skin from an adult human and will have been “reprogrammed” as nerve cells. Merab Kokaia will be collaborating with neuro-researchers Malin Parmar and Olle Lindvall on the project.
The three Lund researchers have received a grant of USD 75 000 from the Michael J. Fox Foundation, started by actor Michael J. Fox and dedicated to Parkinson’s research.
The light-sensitive protein is obtained from a bacterium, which uses light to gain energy. Since it is not a human protein, the safety checks will be extra strict if the method is to be used on humans.
”We know that this is long term research. But the methodology is interesting and it will be exciting to see what we can come up with,” says Merab Kokaia.
(Source: lunduniversity.lu.se)