Coloured lights could be used to find treatments for brain disorders such as epilepsy, a study has suggested.

A Massachusetts Institute of Technology team discovered a way to shut down brain activity using flashes of yellow and blue lasers.

They hope to adjust this to switch off neurons that generate an electrical impulse abnormally, causing seizures.

This could help experts understand how the brain works and, ultimately, offer treatment targets, Nature reports.

The work relies on two genes found in natural organisms like algae that need light to make energy.

Illuminating

These genes, known as Arch and Mac, contain the genetic code for light-activated proteins.

The MIT team engineered brain neurons to express Arch and Mac.

By doing this, they were able to control the brain cells of mice and monkeys using light.

Light activates proteins which, in turn, lowers the voltage in the neurons and prevents them from generating an electrical signal, known as firing.

Arch responds to blue light, Mac to yellow, and both recover afterwards.

Now the researchers plan to closely examine the neural circuits of the brain in the lab to find targets that, when shut down, could treat epilepsy as well as other conditions including Parkinson’s disease and chronic pain.

Ed Boyden, who led the research, said: “Silencing different sets of neurons with different colours of light allows us to understand how they work together to implement brain functions.

“These tools will help us understand how to control neural circuits, leading to new understandings and treatments for brain disorders.”

Although the work has involved animals, it should shed light on what is happening in humans, he said.

Professor Gero Miesenbock of Oxford University has been using the same technology in his research, which has included studying memory formation in fruit flies.

He has said the technology is “beginning to yield previously unattainable insight” into the organisation and regulation of the neural circuits of the brain, and the link between patterns of cellular activity and behaviour.

Characterized by pauses in breathing when sleeping, sleep apnea is one of the most common disorders and affects and estimated 15 million Americans.

For the sake of study, 71 healthy people who were regular users of Ecstasy, i. e., those who had used the drug at least 25 times, but had been off it for nearly 2 weeks prior to the study, and 62 healthy people who had never used the drug, were enrolled, and monitored all night in a sleep laboratory.

After analysis of the data collected, researchers concluded that ecstasy users were at least 8 times more at risk of developing the sleeping disorder than others.

“People who use ecstasy need to know that this drug damages the brain and can cause immediate and dangerous problems such as sleep apnea. Sleep apnea in itself is dangerous, but it can also contribute to thinking problems in people who use ecstasy because chronic sleep disruption is known to have a negative effect on how a person functions during the daytime”, said Dr. McCann.

Forms of obesity and eating disorders can be defined as chronic relapsing conditions with alternating periods of abstinence (dieting to avoid “forbidden” foods-rich in sugar and fat also known as palatable foods) and relapse (compulsive, often uncontrollable, eating of highly-palatable foods) that continue despite negative consequences.

Although the positive reinforcing properties of palatable foods are well known, less attention has been given to the increased probability of a behavioral response produced by removal of an aversive stimulus (intake of palatable food to relieve negative emotional states).

The researchers used 155 rats to measure the neurobiological responses. The first group, the diet cycled subjects, repeatedly ate standard rat chow for five days, followed by a highly palatable, high-sugar, chocolate-flavored chow for two days. The second group ate only standard food. The amount of food consumed was not restricted for either group. When the diet-cycled rats were fed standard chow, they showed less motivation to obtain it, refused it, although it was previously acceptable, and they exhibited anxiety. However when the rats resumed eating the palatable food, they overate and their anxiety-related behaviors returned to normal.

The researchers then looked at the role of the brain’s stress system, which contributes to cycles of drug and alcohol binging and withdrawal, in driving these behaviors. They found that during abstinence from palatable foods, the rats showed increased corticotropin-releasing factor (CRF) gene expression and peptide in the amygdala, an area of the brain involved in fear, anxiety and stress responses. Similar to the anxiety, only when the diet-cycled group was fed palatable food did CRF levels return to normal. Importantly, the blockade of the CRF receptor 1 with a selective antagonist was able to prevent all the behavioral outcomes of palatable food withdrawal.

According to the researchers, CRF is a key stress neurotransmitter. “In observing the activation of the amygdaloid CRF system during abstinence from palatable foods, we understood the causes of recurrent dieting failures,” said study co-author Pietro Cottone, PhD, an assistant professor and co-director of the Laboratory of Addictive Disorders in the Department of Pharmacology and Experimental Therapeutics at BUSM.

“CRF activation during abstinence from palatable foods induces a negative emotional state which is responsible for signs of anxiety and contributes to relapse to ‘forbidden foods,’” added study co-author Valentina Sabino, PhD, an assistant professor and co-Director of the Laboratory of Addictive Disorders in the Department of Pharmacology and Experimental Therapeutics at BUSM. “The stress experienced by frequent dieters in abstinence from palatable food has neurobiological similarities to the negative emotional state of drug and alcohol addicts.”

In addition to Cottone and Sabino, the paper, “CRF system recruitment mediates dark side of compulsive eating,” was authored by Marisa Roberto, Michal Bajo, Lara Pockros, Jennifer B. Frihauf, Eva M. Fekete, Bruno Conti, George Koob and Eric Zorrilla from the Scripps Research Insitutute; Luca Steardo of the University of Roma La Sapienza (Rome, Italy); Kenner C. Rice of the National Institute on Drug Abuse of the National Institutes of Health (NIH), and Dimitri E. Grigoriadis of Neurocrine Biosciences.

This study was supported by the National Institute on Drug Abuse; the National Institute on Alcohol Abuse and Alcoholism; the National Institute of Diabetes and Digestive and Kidney Diseases; the Pearson Center for Alcoholism and Addiction Research; the Intramural Research Programs of the National Institute on Drug Abuse and the National Institute on Alcohol Abuse and Alcoholism.

That’s just what the Interactive Autism Network is doing. Parents of children with autism from around the country collaborate in building what has become the largest online autism registry in the world. The IAN registry was launched by Baltimore’s Kennedy Krieger Institute in 2007. By making use of the power of the Internet, it has registered 30,000 people from all 50 states. The database created by this volunteer effort is being used by autism researchers around the world and is also used to match families with individual studies they can join.

The more families that join such a database, the more accurate and useful the research that comes out of it is likely to be. “Eighty percent of studies in the U.S. never get completed because they never get enough subjects,” says Paul Law, director of the IAN Project. “We’re trying to overcome that problem by connecting families with researchers.” Law’s latest research, published in Archives of Pediatric and Adolescent Medicine, found that parents do a good job at describing a child’s autism spectrum disorder. That’s interesting, because one of the shortcomings of the new 1-in-100 number (from a separate study) is that the increase could be due to greater awareness of autism, better screening by doctors, and more inclusive survey questions. Here’s the link for information on joining the IAN Project.

Grandparents can help, too; The Interactive Autism Network just launched a project aimed specifically at them. This first-ever survey is designed to bring grandparents’ knowledge of their grandchildren into the research mix. Here’s information on the grandparents’ project, and here’s a link to the grandparents of children with autism spectrum disorders survey.

One good thing has already come out of the IAN Project—277 sets of twins have joined, the world’s largest registry of twins with autism. That’s important, because twin studies are the gold standard for researching heredity in diseases. Identical twins are genetic carbon copies, making it easier to study similarities and differences, while fraternal twins are as genetically diverse as siblings who are not twins. Twins with autism have been studied for decades, but this large group of twins is already providing new insights:

• Autism has a strong genetic component, making it the most heritable psychiatric disorder. Law’s latest study confirms that.

• The number of fraternal twins with autism is rising, making it likely that environmental factors are causing more cases. Genetics is less of a factor for causing autism in fraternal twin pairs, since they don’t have identical genes.

• It’s more than twice as common for both twins in a fraternal boy-boy pair to have autism than a pair of boy-girl twins.

The IAN Project won’t help solve the pressing question of which, if any, environmental factors are causing autism; since participants volunteer themselves, it can’t give a clear picture of how a single population might be affected by pollution or other factors. But it does give parents of children with autism—and their grandparents—a way to actively participate in trying to solve the mysteries of this baffling, often terrible disorder.

The condition, which affects equal numbers of men and women, is described as a “fixation on righteous eating”.

Experts says sufferers with the obsession for healthy eating tend to be aged over 30, and were middle-class and well-educated.

“I am definitely seeing significantly more orthorexics than just a few years ago,” said Ursula Philpot, chair of the British Dietetic Association’s mental health group.

Deanne Jade, founder of the National Centre for Eating Disorders, added: “There is a fine line between people who think they are taking care of themselves by manipulating their diet and those who have orthorexia.

“I see people around me who have no idea they have this disorder. I see it in my practice and I see it among my friends and colleagues.”

The condition, named by a Californian doctor, Steven Bratman, in 1997, involves rigid eating eating which includes not touching sugar, salt, caffeine, alcohol, wheat, gluten, yeast, soya, corn and dairy foods.

Any “bad” foods that come into contact with pesticides, herbicides or contain artificial additives are also banned.

The obsession can lead to some sufferers ending up malnourished, lead to pressures in personal relationships and make them become socially isolated.

Until recently doctors only included them under the “catch-all label of Ednos” – eating disorders not otherwise recognised.

While exact numbers of people suffering the disorder are not available, experts say it now represents a significant proportion of the Ednos group.

This has lead to calls that it should be treated in its own right.

Ms Philpot, a senior associate lecturer at Leeds Metropolitan University, told the Observer that while other eating disorders focussed on quantity of food, orthorexics can be overweight or look normal.

“They are solely concerned with the quality of the food they put in their bodies, refining and restricting their diets according to their personal understanding of which foods are truly ‘pure’,” she said.

Nutritional consultant Ian Marber, who is also aka The Food Doctor, told the Daily Telegraph earlier this month that the “very worrying phenomenon” was becoming more prevalent in men.

“It’s an obsessive fixation on eating so healthily that it becomes dangerous, characterised by feeling proud and superior by virtue of how little one eats,” he said.

http://www.telegraph.co.uk/health