Your brain sees your hands as short and fat

Knowing something like the back of your hand supposedly means that you’re very familiar with it. But it could just as well mean that you think it’s wider and shorter than it actually is. As it turns out, our hands aren’t as well known to us as we might imagine. According to Matthew Longo and Patrick Haggard from University College London, we store a mental model of our hands that helps us to know exactly where our limbs are in space. The trouble is that this model is massively distorted.
To keep track of where your various body parts are, your brain maps your posture by processing information from your muscles, joints and skin. Close your eyes and move around a bit, and you’ll still have a good idea of what position you’re in even if you can’t see or touch yourself. But there’s no such direct signal that tells your brain about the size and shape of your body parts. Instead, your brain stores a mental model with those dimensions mapped out.
To visualise this model, Longo and Haggard asked volunteers to hide their hand under a board and use a baton to indicate the position of ten landmarks – the tip and base knuckle of each finger. Their answers were surprisingly inaccurate.

They underestimated the lengths of their fingers by anywhere from around 5% for their thumb and over 35% for their ring and little fingers. In contrast, they overestimated the width of their hand by around 67%, and particularly the distance between their middle and ring knuckles. Our mental hand is a shorter, wider version of our real one. Longo and Haggard found the same thing if they asked the recruits to angle their hands at 90 degrees under the board, and if they tested the right hand as well as the left.
These distortions actually reflect how sensitive each part of the hand is. The skewed mental map is remarkably similar to another map called Penfield’s homunculus, which charts the areas of the brain’s somatosensory cortex (the bit that processes touch information) that is devoted to each body part. Regions that have a more acute sense of touch correspond to larger parts of the homunculus, but they also loom bigger in our mental map. Regions that are less sensitive are smaller on both charts.
As we move from the thumb to the little finger, our digits become less sensitive and the mental map increasingly underestimates their true size. The back of the hand is more sensitive to movement across it than movement along it; accordingly, our mental map depicts a wider, shorter hand.
And we have no idea about this. Consciously, the volunteers had a pretty good appreciation of the size and shape of their hands. When Longo and Haggard showed them a selection of hand images and asked them to select the one that best matched their own, they did so very accurately. But even though they passed this test, they still failed to place the baton in the right place when their hands were hidden.
If we hold such a distorted depiction of our own hands, how is it that we ever grasp things successfully? It’s possible that our motor system uses a different model but Longo and Haggard put forward two more plausible ideas: that cues from vision are strong enough to override the warped map; and that we learn to correct for the misshapen model. Only by removing both of these factors did they finally reveal how skewed our perceptions actually are.

Does brain training work?

• There's quite a dispute going over whether brain training can improve cognitive function or not.

Learning RX is putting on a public relations push on June 15 to let people know that "not all mental exercise is brain training. Founder Ken Gibson says a recent study showed no improvement in mental fitness when people used online brain activities for 10 minutes a day, three times a week over a 6-week period, because that routine lacked sufficient intensity.

"Intensity is key," according to Gibson, who likens it to physical training. He advocates for exercises that "continue to push the brain to do more challenging activities, in shorter time, with more distractions and additional tasks." He makes the analogy between a 3-day-a-week 10-minute stroll and the effects of increasingly tough 1-hour workouts six times a week with a personal trainer. He claims that graduates of LearningRX typically show gains between 20 and 49 percentage points across nine cognitive areas. Visitors to www.learningrx.com can download a free book "Unlock the Einstein Inside: Applying New Brain Science to Wake up the Smart in Your Child."

Distorted body image means people don't know the back of their own hands

A study suggests our brains have highly distorted representations of the size and shape of our own hands. The distortion may extend to other body parts, skewing body image

True locations of knuckles and tips of each finger (black dots) and subjects' judgements of where they are (white dots). Average hand shape is given as solid lines for the actual hand and as dotted lines for subjective judgements. Diagram: PNAS

You may think you know the back of your hand like, well, the back of your hand. But think again. Scientists have found that our brains contain highly distorted representations of the size and shape of our hands, with a strong tendency to think of them as shorter and fatter than they really are.
The work could have implications for how the brain unconsciously perceives other parts of the body and may help explain the underpinnings of certain eating disorders in which people's body image becomes distorted.
In the study, neuroscientists at University College London asked more than 100 volunteers to place their left hand palm-down on a table. The researchers covered the volunteers' hands with a board and then asked them to indicate on it where they thought landmarks such as fingertips and knuckles lay underneath. This data was used to reconstruct the "brain's image" of the hand.
The results, published today in the Proceedings of the National Academy of Sciences, showed a consistent overestimation of the width of the hand. Many of the volunteers estimated their hand was around 80% broader than it really was.
"It's a dramatic and highly consistent bias. It was the same with estimation of finger lengths. When you get to the ring finger, with the largest bias, it's 30-40% underestimation," said Matthew Longo of UCL's Institute of Cognitive Neuroscience, who led the work.
The brain uses several ways to work out the location of different parts of the body. This includes feedback from muscles and joints and also some sort of internal model of the size and shape of each body part.
"Previously it has been assumed that the brain uses a perfectly accurate model of the body and it's not mysterious where that might come from," said Longo. "We see our body all the time and it wouldn't be surprising if the brain had developed an accurate representation of the body."
Instead, Longo's work shows that the brain's internal models can be hopelessly wrong. The errors could partly be explained because of the way the brain allocates its processing capacity, said Longo. Regions of high sensitivity in the skin, such as the fingertips and the lips, get a correspondingly larger proportion of the brain's territory.
Longo said that this sensitivity was mirrored in the relative size of the fingers in the maps of perceived positions. "You find the least underestimation for the thumb and more underestimation as you go across to the little finger. You see the same pattern if you measure tactile sensitivity."
The research was carried out on the hand because there were obvious landmarks for the volunteers to point out, which could then be used by the researchers to draw the brain's image of the hand. But the results might be applicable across the body.
"It would be very surprising if there was a distorted representation of the hand but an accurate representation of the complete rest of the body. That would be a bizzare finding, so my guess is that there would be similar sorts of biases, perhaps bigger ones, on other parts of the body," said Longo.
He said the research showed how the brain's ability to distort its representation of the body might underlie certain psychiatric conditions involving body image such as anorexia nervosa.
"It's interesting to note that what we find for the hand is that the representation seems to be 'too fat'. If there's an implicit default representation of the brain to perceive the body as overly wide, then that could potentially account for the pattern you get with eating disorders."
He added: "Our healthy participants had a basically accurate visual image of their own body, but the brain's model of the hand's underlying position sense was highly distorted. This distorted perception could come to dominate in some people, leading to distortions of body image as well, such as in eating disorders."

Hand study reveals brain's distorted body model

The human brain Our brains contain a highly distorted model of our own bodies, according to new research by scientists at UCL (University College London). A study published today, which focussed on the brain's representation of the hand, found that our model of our bodies is out of sync with reality - with a strong tendency to think that the hands are shorter and fatter than their true shape.

The results of the study, published in the journal Proceedings of the National Academy of Sciences, show that the brain maintains a model of the hand in which our fingers are perceived to be shorter and our hands fatter than they are. Neuroscientists suspect the reason for these distortions may lie in the way the brain receives information from different regions of the skin.
Dr Matthew Longo, lead author from the UCL Institute of Cognitive Neuroscience, said: "The phrase "I know the town like the back of my hand" suggests that we have near-perfect knowledge of the size and position of our own body parts but these results show that this is far from being the case."
"Our results show dramatic distortions of hand shape, which were highly consistent across participants. The hand appears to be represented as wider than it actually is and the fingers as shorter than they actually are - a finding that might also apply to other parts of the body," added Dr Longo.
Participants in the study were asked to put their left hands palm down under a board and judge the location of the covered hand's knuckles and fingertips by pointing to where they perceived each of these landmarks to be. A camera situated above the experiment recorded where the participant pointed. By putting together the locations of all the landmarks, the researchers reconstructed the brain's model of the hand, and revealed its striking distortions.
The research, which was funded by the Biotechnology and Biological Science Research Council (BBSRC), aims to find out how the brain knows where all parts of the body are in space even when your eyes are closed - an ability known as 'position sense'. Neuroscientists think that position sense requires two distinct kinds of information. Signals that the brain receives from muscles and joints play an important role in position sense, but the brain also needs a model of the shape and size of each body part. For example, to know where the fingertip is in space, the brain needs to know the angles of joints in the arm and hand, but also the length of the arm, hand, and finger.
It is this model of our body's size and shape that is investigated in the study. "Of course, we know what our hand really looks like" said Dr Longo, "and our participants were very accurate in picking out a photo of their own hand from a set of photos with various distortions of hand shape. So there is clearly a conscious visual image of the body as well. But that visual image seems not to be used for position sense."
The results showed that in this task people estimated that their hands were about two-thirds wider and about one-third shorter than actual measurements.
Neuroscientists suspect that the brain's distorted model of body shape result is due to the way the brain represents different parts of the skin. For example, the size of the brain representation of the five fingers gets progressively smaller for each finger between the thumb and the little finger, mirroring the relative size of fingers in the body model reported in this study.
"These findings may well be relevant to psychiatric conditions involving body image such as anorexia nervosa, as there may be a general bias towards perceiving the body to be wider than it is. Our healthy participants had a basically accurate visual image of their own body, but the brain's model of the hand underlying position sense was highly distorted. This distorted perception could come to dominate in some people, leading to distortions of body image as well, such as in eating disorders," said Dr Longo.

Rewiring the brain

Program teaches people how to rethink their relationships with food


As an information technology guy, Jon Backus has spent the majority of his career around wires.
Backus, a Hagerstown resident, is IT manager for Covenant Health System in Bethesda, Md.
But lately, Backus has set his sights on a different kind of wiring - the hard wiring in his brain - with hopes that it will lead to weight loss.
Backus is one of nearly 100 participants in Wired for Joy, a program that attempts to help people lose weight by changing how they think.
"It made sense to me," said Backus, 49, who said he's lost a few pounds since he started last year.
"Wired for Joy" is the introductory course in a series built around making people more psychologically resilient to stress.
Researchers have identified stress as a trigger for overeating. It's a concept referred to as emotional brain training, or EBT, said Tammy Thornton, a registered dietitian with the Washington County Health Department and a workshop leader.
Washington County Health Department has offered the Wired for Joy and EBT courses since the fall of 2009. Workshop leaders are hoping to drum up publicity for the health department's next round of classes during an event at Borders on Thursday, June 17. The event is tied to the release of "Wired for Joy," written by Laurel Mellin.
A new approach
Up until recently, many of the approaches to weight loss homed in on eating and exercise habits.
But EBT aims to work out the brain, too, said Lisa McCoy, a registered dietitian with the health department.
"We have wired our brains for stress," said McCoy, who also leads workshops.
McCoy said when people face stress, they often seek external sources such as food to ease the stress. Repeating the habit of eating when stressed from an early age hard-wires the message that food can be a source of comfort and safety, she said.
Backus said he thinks that might be why diets and exercise alone weren't working for him.
"Throughout my whole life I've struggled with weight," he said.
He said he had already developed an interest in the concept of emotional intelligence, but said it wasn't until two or three weeks ago that he made the connection between his eating habits and what was going on in his head.
"I tend to be even-keeled or upbeat most of the time," Backus said.
He said he wasn't eating when he was stressed. Instead, he rewarded himself with food.
"I had that wiring to eat when I wasn't hungry," he said.
'Wired' tied to a statewide effort
Health officials consider obesity to be a public health issue because it increases the risk for heart disease, diabetes, cancer and other health problems.
In Maryland, 26 percent of the population was considered obese in 2008, according to data from the U.S. Centers for Disease Control and Prevention.
Physicians use body mass index, or BMI, as an indictor for body fat and weight. A person's BMI is calculated using the person's weight and height. The CDC defines obesity as having a body mass index or BMI of 30 or greater.
Combating obesity is tied to a broader statewide effort aimed at chronic disease prevention.
"We've seen a 47 percent increase in the prevalence of obesity in 10 years in Maryland," said Audrey S. Regan, director for the office of Chronic Disease and Prevention, part of the state's Department of Health and Mental Hygiene.
The state's Office of Chronic Disease and Prevention used $1.4 million in federal funds for evidence-based health initiatives tied to preventing chronic disease.
Regan said Washington County Health Department was one of the 13 health departments statewide to receive the competitive grant.
Regan said Washington County Health Department received a three-year grant totaling $525,000 for its Wired for Joy and EBT programing.
Learning to check-in
Backus said daily "check-ins" help him become more aware of his triggers or overeating.
McCoy began the June 9 Wired for Joy class with a check-in drill at the Western Maryland Hospital Center. Seven seated participants closed their eyes and listened to McCoy, who instructed them to relax focus on their breathing. The idea was for the participants to become more in tune with their emotional state at that moment.
"Find your own rhythm and notice that your body begins to relax," McCoy said, urging the participants to connect with their inner sanctuaries, or "that place they can go to at any time."
McCoy said participants are encouraged to have five mini check-ins throughout the day: once in the morning; once before breakfast lunch and dinner, and once before bed.
Backus said now that he's aware of his trigger, he said he's better able to seek out healthier rewards. So instead of rewarding himself with a candy bar and soda, he said the reward can be straight forward - such as simply accepting that he's happy and unstressed.
The idea is that over time, this mental process will happen subconsciously - thanks to a rewired brain.
"Time will tell whether I've been rewired," Backus said.

Religion and the Disappearing Right Brain

From Tom Rees of Epiphenom:

Studies of brain damage give us a unique insight into how the mind works. If your behavior changes when a specific lump is taken out, then that’s pretty good evidence for the function of that particular lump.
So what happens when half your brain starts to rot away? Dennis Chan, a neurologist at the Institute of Neurology in London, decided to find out.
“Right temporal lobe atrophy” is a rare condition in which a major part of the right side of the brain simply withers away. You can see a particularly severe case in the picture above (the right side of the brain is on the left). Chan and his colleagues compared 20 of these patients with 20 patients whose left-hand side of the brain was withered.
As you might expect, all of these people have some serious psychological problems. But for people with left-brain atrophy, the problems are obvious. That’s because this side of the brain controls speech and (for most people) the dominant hand. You can pretty readily spot somebody with left-brain atrophy.
Right brain atrophy is altogether more subtle, and also weirder. These patients get lost easily. They find it difficult to recognize faces, and they have a variety of behavioral disorders, including disinhibition and obsessions. One patient insisted on having all the light switches in her house painted gold and silver!
And, interestingly, three patients were “hyper-religious.”
Now, the researcher don’t describe what they mean by this term, and three patients (15 percent) might not sound like a lot, but none of the patients with left-brain atrophy were hyper-religious. Two patients also had “complex visual hallucinations of inanimate objects’”and two had sensory crossover, in which stimulation of one sense was experienced as a different sense.
Damage to the right brain—albeit the parietal lobes rather than the temporal lobes—has been linked to religiosity previously. Brick Johnstone and Bret Glass found that people with damage in this region were more spiritual, and Cosimo Urgesi and his colleagues have found that tumors in this part of the brain also increases religiosity.
That’s perhaps because the right-hand side of the brain tends to play an important role in spatial awareness.
However, for the sake of the statistical purists who sometimes drop by, I should point out that correlation is not causation. Although it seems likely that brain atrophy leads to religion, you can’t rule out the possibility of the reverse.

The brain may control cholesterol

Cholesterol levels are controlled by a “hormone in the brain” the Daily Mail has reported.

It says the finding offers hope of new treatments to reduce levels of “the dangerous fat”.
The Mail’s story is based on animal research that appears to indicate that blood cholesterol levels are regulated remotely by the central nervous system. The researchers found that increasing levels of a hormone called ghrelin, which is thought to regulate energy intake, caused mice to develop higher levels of cholesterol. The finding that cholesterol can be regulated by the brain could be the basis for new drug treatments, they suggest.
The findings are interesting, but it is important to stress that there are large differences in the way cholesterol affects mice and humans. This is early research that points the way to further research into ghrelin, although more human studies are needed to draw firm conclusions about the brain regulating human blood cholesterol levels. It’s also important to note that, in humans, cholesterol levels can be controlled by diet, exercise and, where necessary, drug treatment.

Where did the story come from?

The study was carried out by researchers from various centres including the University of Cincinnati College of Medicine in Ohio, Indiana University at Bloomington and the Institute of Animal Science in Schwerzenbach, Switzerland. It was funded by grants from the US National Institutes of Health and published in the peer-reviewed medical journal Nature Neuroscience.
The study’s main findings were reported accurately by the BBC, which pointed out that the findings need to be replicated in humans. Its story also included advice on controlling cholesterol from the British Heart Foundation.
The Daily Mail also pointed out that more work is needed, but incorrectly identified high-density lipoprotein (HDL) as the type of  cholesterol that can lead to hardening of the arteries and called low-density lipoprotein (LDL) ‘good’ cholesterol. This is the wrong way around. The Mail’s headline also claimed that the findings gave “hope for new drugs” and the story went on to say that current drugs for cholesterol, called statins, have many side effects. It did not point out that any new drug for cholesterol will need to go through several stages to test for efficacy and safety before being made available or that any new drug also has a risk of side effects.

What kind of research was this?

Cholesterol is a fat-like substance that circulates in the blood. HDL, or ‘good’, cholesterol is beneficial, while high levels of ‘bad’ LDL cholesterol carry a risk of cardiovascular disorders, such as heart disease. Research so far has found that, in humans, blood levels of cholesterol are regulated by dietary intake and synthesis by the liver.
The researchers point out that lipid disorders such as high cholesterol, together with obesity, high blood pressure and impaired glucose metabolism, all raise the risk of cardiovascular disorders and obesity can raise the risk of diabetes.
Efforts to find drugs for these disorders have found that the hormone ghrelin, produced by the gut, and believed to inform the brain about energy availability, is already implicated in some of these disorders.
Ghrelin is believed to have an effect on a chemical called melanocortin produced by the part of the brain called the hypothalamus. Melanocortin in turn regulates factors such as fatty tissue, glucose metabolism and blood pressure. The researchers wanted to test their hypothesis that a neural circuit in the brain, the “gut-brain axis” involving both ghrelin and melanocortin, controls levels of blood cholesterol.
This was an animal study, conducted in the laboratory, using mice and rats to test the researchers’ hypothesis that cholesterol levels are regulated by the central nervous system. However, because cholesterol and the hormones were not measured in humans, its results may have only limited relevance.

What did the research involve?

The researchers conducted several experiments on a group of mice and rats. All the procedures used were in line with US guidelines for the care and use of laboratory animals and approved by the relevant institutions.
The mice in one group were given daily injections of ghrelin under the skin for one week, while another group of mice acted as a control. In a separate experiment, the researchers attempted to find out if the effects of ghrelin were limited by a chemical called melanocortin receptor antagonist (MC4R). To do this they deleted or chemically blocked the production of MC4R.
The animals were humanely killed and tissues frozen and their cholesterol levels analysed using standard chemical methods.

What were the basic results?

The researchers found that giving the mice the hormone ghrelin for one week not only caused the expected increase in body fat, but also significantly increased total blood cholesterol levels, compared with a control group. Levels of blood glucose and fats called triglycerides remained unchanged.
They also found that when they genetically deleted or blocked the melanocortin receptor (MC4R) in the central nervous system of the mice, it produced increased levels of ‘good’ HDL cholesterol. They thought part of the reason for this might be that the neural circuit reduces the uptake of cholesterol by the liver.

How did the researchers interpret the results?

The researchers conclude that the neural circuit in the brain involving the hormone ghrelin directly controls cholesterol metabolism by the liver. They say their study shows for the first time that cholesterol is under remote but direct control by specific neuroendocrine circuits in the central nervous system. They say this may lead to new drug treatments that can modulate melanocortin and, therefore, treat high cholesterol as well as other disorders related to the metabolism.

Conclusion

This is an interesting laboratory study that showed that, in mice, levels of blood cholesterol can be increased by raising the levels of the hormone ghrelin and blocking the melanocortin receptor. This suggests that the central nervous system has a role in the production of cholesterol.
However, more work is needed before these findings could be directly applied to humans. In addition, any new drug treatments based on this hypothesis would have to undergo several stages of trials for safety and efficacy before they could be made available to humans.
It’s important to note that there is good evidence that human cholesterol levels can be controlled by eating a diet low in saturated fats, exercising regularly and, where necessary, with drug treatment.

Resveratrol supplements shown to improve cognitive function

A recent small scale study of synthetic resveratrol by DSM done on mice, indicated a possible improvement in the animals’ memory. Biotivia has gone an important step further in a human trial done at Northumbria University on brain blood flow, in which it was shown that their Bioforte all-natural resveratrol improved this brain function in humans.  Biotivia has been the leading provider of resveratrol for health studies on both animals and humans for the past five years.
Synthetic versions of resveratrol are made in China and India using either organic chemistry, a process in which a target molecule is created from a broth of chemicals, or by fermentation, an often problematical system in which genetically modified (GMO) bacteria or yeast are made to create the molecule.  Both methods often leave significant amounts of unknown contaminants in the resveratrol. This is why Biotivia uses natural resveratrol produced from the wild organic polygonum cuspidatum plant to produce its proprietary resveratrol.

Biotivia’s Managing Director, James Betz stated recently, We do not believe that the risks of using GMO derived synthetic resveratrol in our supplements is warranted simply by the obvious economic advantages of this material. Our research partners are in agreement with this decision.” The drawbacks of synthetic versions of natural compounds were highlighted recently when a trial of Glaxo Smith Kline’s analog of resveratrol called SRT 501 was halted due to “unexpected safety concerns”. No toxicity has been observed in natural resveratrol over hundreds of animal and human trials during the past 20 years. The proven purity, safety and lack of toxicity of natural resveratrol means that Biotivia’s supplements may be safely used not only in animal trials, but in human trials as well, such as the one at Northumbria and many others in which Biotivia’s resveratrol has been shown to produce impressive health benefits.  This is important because clinical trials done on animals, especially on parameters such as memory and cognition, have very limited value in terms of their applicability to humans.
The Northumbria human clinical trial on university students showed that strong improvements in the human subjects’ brain blood flow resulted from oral administration of Bioforte resveratrol. The brain’s ability to solve problems, create new ideas and simply to think and reason requires a healthy level of cerebral blood flow. A deficiency of which is a cause of debilitating strokes and other brain damage and can result in dementia and impaired motor skills and cognition.

Cerebral blood flow dramatically increased
In the double blind, peer-reviewed, published study at the University of Northumbria, UK, a dose of either 250mg or 500mg of Resveratrol was shown to increase cerebral blood flow by just over 100% to 200% respectively in 22 university student subjects.  Another study performed by Scientists at the University of Missouri-Columbia recently found that Resveratrol may also lessen brain damage from strokes.

In the Northumbria University study, the students were given either one or two 250mg capsules of a supplement called Bioforte Resveratrol approximately 45 minutes before taking a mental test which required them to rapidly solve simple math problems presented on a computer.

Both Resveratrol doses resulted in increased cerebral blood flow during mental tasks, and was measured by the total concentration of cerebral deoxyhemoglobin after the students were given Resveratrol, which suggests enhanced oxygen extraction.

The increase was noticeable toward the end of the 45-min absorption phase and throughout the task performance phase. The control group of students who were not given Resveratrol showed no difference in brain blood flow or problem solving ability. These results appear to confirm that single doses of Resveratrol taken orally can increase cerebral blood flow in human subjects.

Could Resveratrol help increase cognition on demand?

“It is very interesting to note,” states James Betz PhD, managing director of Biotivia, the company whose Resveratrol was used in the study, “that the increase in blood flow occurred essentially “on demand”.  That is, when the students were not concentrating on the math problems, blood flow was slightly above normal … but as soon as they were called upon to solve the problems, blood flow increased substantially.”

Betz continued: “It’s essentially just-in-time mental agility, with important ramifications for students, business people, or anybody who needs a mental boost from time to time to help deal with a particularly challenging task.” This study, as well as a growing number of in vitro and human clinical trials at the National Institute of Health, and at university medical schools and research organizations in the US and Europe, illustrates the remarkable range of potential health benefits of the Resveratrol molecule both for the prevention and treatment of a wide range of medical conditions.

Biotivia Resveratrol is also being used in studies currently underway at the Albert Einstein Medical Center, New York, investigating Resveratrol’s potential neuro-protective properties as a possible therapeutic aid to Alzheimer and dementia sufferers. Another university research project is investigating Biotivia’s Bioforte Resveratrol potential to increase insulin sensitivity in diabetes and metabolic syndrome patients.

Biotivia recently announced a collaboration with the University of Ferrara ThalLab on human clinical trials of Resveratrol for the treatment of Thalassemia at two hospitals in Italy and one large medical center in Egypt.

About Biotivia Bioceuticals

Biotivia was established in 1992 in Vienna, Austria as a supplier of natural raw materials and botanicals to the supplement and functional food industries, and to researchers and scientific institutions worldwide. The company has a range of unique Resveratrol-based formulations for consumers at www.biotivia.com.

About Northumbria University Northumbria University, in Newcastle upon Tyne, is an expanding multicultural learning community, with excellent links with further and higher education, industry and commerce throughout the UK, Europe and beyond.

Brain circuits that control habitual learning identified

EU-funded scientists have identified two brain circuits that are involved in habitual learning such as finding our way to and from work. The new findings, published in the journal Neuron, have implications for the study of Parkinson's disease, substance abuse and many psychiatric disorders.

The discovery is an outcome of the SELECT-AND-ACT ('The role of striatum in selection of behaviour and motor learning: neuronal code, microcircuits and modelling') project, which is funded with EUR 2.5 million through the Health Theme of the EU's Seventh Framework Programme (FP7).

Daily habits are formed by the simple process of repetition and exploring through trial and error. We often carry out routines without thinking about them or noticing them very much. For example, one might walk home from the usual train stop while daydreaming about something else entirely.

Scientists have long explored how we are able to learn a routine well enough to perform it without thinking. In this latest study, researchers focused on the basal ganglia, a remarkable group of neurons in the mammalian brain that are involved in various functions ranging from movement to emotion and thinking.

Previous studies have indicated that the largest structure in the basal ganglia, the striatum, may be important in reward-based learning. One part of the striatum controls movement and is connected to the sensorimotor cortex, which is involved in planning and executing voluntary functions. Another circuit in the striatum controls flexible behaviour and is connected to the 'association cortex', which processes and integrates sensory information.

Until now, little has been known about how these two separate circuits contribute to learning new behaviours. In this study, researchers based at the Massachusetts Institute of Technology (MIT) in the US recorded the activity of the two striatal circuits in rats learning to find their way to a cache of chocolate-flavoured sprinkles in a maze. To make their way to the sprinkles, the rats had to figure out the meaning of sound and touch cues delivered at a T-junction in the maze. They kept trying until the journey became routine.

As the rats' performance improved, the circuits showed distinctive activity patterns that evolved during the learning process. One became most active when the rats had to take specific actions (e.g. start, stop or turn) and got stronger as the routine was learned. The other became very active when the rat had to decide which way to turn, but as the rat learned the route the signal became weaker.

'We think the two basal ganglionic circuits must work in parallel,' said Catherine Thorn of MIT, first author of the study. 'We see what looks like competition between the two circuits until the learned behaviour becomes ingrained as a habit.'

'These brain circuits are affected in Parkinson's disease, substance abuse and many psychiatric disorders,' explained MIT's Ann Graybiel. 'If we can learn how to tilt the competition in one direction or the other, we might help bring new focus to existing therapies, and possibly aid in the development of new therapies.'