Motor Excitability predicts Working Memory

Humans with a high motor excitability have a better working memory than humans with a low excitability. This was shown in a study conducted by scientists from the Transfacultary Research Platform at the University of Basel. By measuring the motor excitability, conclusions can be drawn as to the general cortical excitability – as well as to cognitive performance.

Working memory allows the temporary storage of information such as memorizing a phone number for a short period of time. Studies in animals have shown that working memory processes among others depend on the excitability of neurons in the prefrontal cortex. Moreover, there is evidence that motor neuronal excitability might be related to the neuronal excitability of other cortical regions. Researchers from the Psychiatric University Clinics (UPK Basel) and the Faculty of Psychology in Basel have now studied if the excitability of the motor cortex correlates with working memory performance– results were positive.

«The motor cortical excitability can be easily studied with transcranial magnetic stimulation», says Nathalie Schicktanz, doctoral student and first author of the study. During this procedure, electromagnetic impulses with increasing intensity are applied over the motor cortex. For subjects with high motor excitability already weak impulses are sufficient to trigger certain muscles – such as those of the hand – to show a visible twitch.

Conclusions for other cortical regions
In the present study, that included 188 healthy young subjects, the scientists were able to show that subjects with a high motor excitability had increased working memory performance as compared to subjects with a low excitability. «By measuring the excitability of the motor cortex, conclusions can be drawn as to the excitability of other cortical areas», says Schicktanz.

«The findings help us to understand the importance of neuronal excitability for cognitive processes in humans», adds Dr. Kyrill Schwegler, co-author of the study. The results might also have important clinical implications, as working memory deficits are a component of many neuropsychiatric disorders, such as schizophrenia or attention deficit hyperactivity disorder. In a next step, the scientists plan to study the relation between neuronal excitability and memory on a molecular level.

The study is part of a project lead by Prof. Dominique de Quervain and Prof. Andreas Papassotiropoulos. The project uses transcranial magnetic stimulation to study the cognitive functions in humans. The goal is to identify the neurobiological and molecular mechanisms of human memory.

Brain Stimulation May Treat Bulimia

A mild electrical stimulation to a specific brain area could be an effective treatment for some patients with eating disorders such as bulimia, who suffer from episodes of severe binge eating and purging behaviors, researchers say.

After one 42-year-old woman received the electrical stimulation, called transcranial magnetic stimulation (TMS), as a treatment for her depression, and showed an unexpected recovery from her 20-year battle against bulimia nervosa, her doctors conducted a pilot study to see whether the treatment would also work for other patients with eating disorders, said Dr. Jonathan Downar, of the University of Toronto. Downar described the study Tuesday (Nov. 12) here at the annual meeting of the Society for Neuroscience.

In the study, Downar and his colleagues recruited 20 patients with bulimia and stimulated a part of their frontal lobes called the dorsomedial prefrontal cortex, which is next to the brain region usually stimulated for treating depression. The patients, who had already tried conventional therapies and medications but had seen no improvement, received 20 sessions of electrical stimulation daily for four weeks.

At the end of the treatment, six of the patients saw their binge eating and purging symptoms almost completely disappear. In another four patients, symptoms improved by more than 50 percent. Eight patients saw only little improvement, and two got worse, Downar said.

Although larger studies and clinical trials are needed to confirm the results of the pilot study, Downar said he is optimistic about the promise of using TMS for treating certain patients with eating disorders.

"There are lots of things you could do to treat disorders like depression, but for these folks [with bulimia], there’s really nothing if they have gone through all of the medications" and therapy options, Downar said.

Eating disorders, such as anorexia and bulimia, affect more than 8 million people in North America. These disorders often carry emotional distress, disrupt the person’s normal life and can even lead to life-threatening medical problems.

TMS is a relatively new technique, and involves a large electromagnetic coil that is placed over the skull, and changes the activity in a targeted brain region by inducing electric currents. Although the change is temporary and reversible, with repeated stimulation, doctors can create lasting changes in neuronal activity. Repeated TMS has been approved by the U.S. Food and Drug Administration as a treatment for some forms of depression.

In the study, the researchers used brain imaging to examine whether differences in brain activity could explain why some patients respond well to TMS treatment while others show little or no improvement.

They found that before the treatment, responders had lower connectivity between the frontal lobe and a set of brain areas (such as the striatum) that are linked to rewards and cravings. This low connectivity could be a sign of impulsiveness, and stimulation may have helped to make the missing connection in these patients’ brains, Downar said.

In contrast, the brains of the people whose bulimia was not helped by TMS appeared more connected in those areas. In these patients, TMS appears to be ineffective in treating bulimia because the brain stimulation is “giving them something they don’t need, because they already have it,” Downar said.

The brain imaging results suggest that doctors may be able to identify which patients will respond to TMS treatment, and spare others from a weeks-long treatment.

"By using brain imaging to detect these patterns, we may eventually be able to predict which patients are most likely to benefit," Downar said.

New hope for heavy smokers after study finds zapping their brains with magnetic pulses made it easier for them to quit

Heavy smokers could be helped to kick the habit by having their brains zapped with electromagnetic pulses, new research suggests.

Repeated use of a high frequency magnet to stimulate the brain helps some smokers quit for up to six months after treatment, an Israeli study found.

The smokers had already tried a range of treatments, from patches to psychotherapy, raising hopes that brain stimulation could be an effective alternative for those who had so far failed to kick the habit.

Abraham Zangen of Ben Gurion University told the annual meeting of the Society for Neuroscience in San Diego, California, that more than half the smokers given high-frequency magnetic pulses quit.

More than a third were still abstaining six months on.

'Our research shows us that we may actually be able to undo some of the changes to the brain caused by chronic smoking,' said Dr Zangen.

'We know that many smokers want to quit or smoke less and this could help put a dent in the number one cause of preventable deaths.'

Dr Zangen’s team recruited 115 heavy smokers aged between 21 and 70 who were interested in quitting but who had failed in doing so on at least two previous attempts.

They then split the smokers into three groups, giving them either high frequency repeated Transcranial Magnetic Stimulation (rTMS), low frequency rTMS, or placebo treatment for 13 days.

Repeated high frequency Transcranial Magnetic Stimulation (rTMS) is a non-invasive technique that uses magnetic fields to stimulate large areas of neurons in the brain.

The researchers focused on stimulating the prefrontal cortex and the insula, which are the two brain areas associated with nicotine addiction.

Before each session, Dr Zangen got one of his PhD students to light a cigarette and take a drag in front of half the smokers in each group to awaken their cravings.

This was to make sure the smokers’ attention was directed at their addiction and not some other craving, said Dr Zangen.

The results were striking. Nearly half - 44 per cent - of the smokers who received the cue before their rTMS session gave up immediately after the 13-day course, with 33 per cent still of the smokes six months later.

Overall, participants who received high frequency rTMS smoked less and were more likely to quit, with success rates four times that of the low frequency group and more than six times greater than the placebo group.

Dr Zangen’s team are now planning a much larger trial involving smokers in several countries, which is set to start in the next few months.

He told The Guardian: ‘It’s quite easy to quit for a few days, or even for a few weeks, but if we can help people quit for more than three months, then they are actually quite unlikely to relapse later on.’

Dr Zanger did reveal that he has a financial interest in the company which provided the Transcranial Magnetic Stimulation equipment used in the study.

Researcher controls colleague’s motions in 1st human brain-to-brain interface

University of Washington researchers have performed what they believe is the first noninvasive human-to-human brain interface, with one researcher able to send a brain signal via the Internet to control the hand motions of a fellow researcher.

Using electrical brain recordings and a form of magnetic stimulation, Rajesh Rao sent a brain signal to Andrea Stocco on the other side of the UW campus, causing Stocco’s finger to move on a keyboard.

While researchers at Duke University have demonstrated brain-to-brain communication between two rats, and Harvard researchers have demonstrated it between a human and a rat, Rao and Stocco believe this is the first demonstration of human-to-human brain interfacing.

“The Internet was a way to connect computers, and now it can be a way to connect brains,” Stocco said. “We want to take the knowledge of a brain and transmit it directly from brain to brain.”

The researchers captured the full demonstration on video recorded in both labs.

Rao, a UW professor of computer science and engineering, has been working on brain-computer interfacing in his lab for more than 10 years and just published a textbook on the subject. In 2011, spurred by the rapid advances in technology, he believed he could demonstrate the concept of human brain-to-brain interfacing. So he partnered with Stocco, a UW research assistant professor in psychology at the UW’s Institute for Learning & Brain Sciences.

On Aug. 12, Rao sat in his lab wearing a cap with electrodes hooked up to an electroencephalography machine, which reads electrical activity in the brain. Stocco was in his lab across campus wearing a purple swim cap marked with the stimulation site for the transcranial magnetic stimulation coil that was placed directly over his left motor cortex, which controls hand movement.

The team had a Skype connection set up so the two labs could coordinate, though neither Rao nor Stocco could see the Skype screens.

Rao looked at a computer screen and played a simple video game with his mind. When he was supposed to fire a cannon at a target, he imagined moving his right hand (being careful not to actually move his hand), causing a cursor to hit the “fire” button. Almost instantaneously, Stocco, who wore noise-canceling earbuds and wasn’t looking at a computer screen, involuntarily moved his right index finger to push the space bar on the keyboard in front of him, as if firing the cannon. Stocco compared the feeling of his hand moving involuntarily to that of a nervous tic.

“It was both exciting and eerie to watch an imagined action from my brain get translated into actual action by another brain,” Rao said. “This was basically a one-way flow of information from my brain to his. The next step is having a more equitable two-way conversation directly between the two brains.”

The technologies used by the researchers for recording and stimulating the brain are both well-known. Electroencephalography, or EEG, is routinely used by clinicians and researchers to record brain activity noninvasively from the scalp. Transcranial magnetic stimulation is a noninvasive way of delivering stimulation to the brain to elicit a response. Its effect depends on where the coil is placed; in this case, it was placed directly over the brain region that controls a person’s right hand. By activating these neurons, the stimulation convinced the brain that it needed to move the right hand.

Computer science and engineering undergraduates Matthew Bryan, Bryan Djunaedi, Joseph Wu and Alex Dadgar, along with bioengineering graduate student Dev Sarma, wrote the computer code for the project, translating Rao’s brain signals into a command for Stocco’s brain.

“Brain-computer interface is something people have been talking about for a long, long time,” said Chantel Prat, assistant professor in psychology at the UW’s Institute for Learning & Brain Sciences, and Stocco’s wife and research partner who helped conduct the experiment. “We plugged a brain into the most complex computer anyone has ever studied, and that is another brain.”

At first blush, this breakthrough brings to mind all kinds of science fiction scenarios. Stocco jokingly referred to it as a “Vulcan mind meld.” But Rao cautioned this technology only reads certain kinds of simple brain signals, not a person’s thoughts. And it doesn’t give anyone the ability to control your actions against your will.

Both researchers were in the lab wearing highly specialized equipment and under ideal conditions. They also had to obtain and follow a stringent set of international human-subject testing rules to conduct the demonstration.

“I think some people will be unnerved by this because they will overestimate the technology,” Prat said. “There’s no possible way the technology that we have could be used on a person unknowingly or without their willing participation.”

Stocco said years from now the technology could be used, for example, by someone on the ground to help a flight attendant or passenger land an airplane if the pilot becomes incapacitated. Or a person with disabilities could communicate his or her wish, say, for food or water. The brain signals from one person to another would work even if they didn’t speak the same language.

Rao and Stocco next plan to conduct an experiment that would transmit more complex information from one brain to the other. If that works, they then will conduct the experiment on a larger pool of subjects.

Early brain stimulation may help stroke survivors recover language function

Non-invasive brain stimulation may help stroke survivors recover speech and language function, according to new research in the American Heart Association journal Stroke.

Between 20 percent to 30 percent of stroke survivors have aphasia, a disorder that affects the ability to grasp language, read, write or speak. It’s most often caused by strokes that occur in areas of the brain that control speech and language.

“For decades, skilled speech and language therapy has been the only therapeutic option for stroke survivors with aphasia,” said Alexander Thiel, M.D., study lead author and associate professor of neurology and neurosurgery at McGill University in Montreal, Quebec, Canada. “We are entering exciting times where we might be able in the near future to combine speech and language therapy with non-invasive brain stimulation earlier in the recovery. This could result in earlier and more efficient aphasia recovery and also have an economic impact.”

In the small study, researchers treated 24 stroke survivors with several types of aphasia at the rehabilitation hospital Rehanova and the Max-Planck-Institute for neurological research in Cologne, Germany. Thirteen received transcranial magnetic stimulation (TMS) and 11 got sham stimulation.

The TMS device is a handheld magnetic coil that delivers low intensity stimulation and elicits muscle contractions when applied over the motor cortex.

During sham stimulation the coil is placed over the top of the head in the midline where there is a large venous blood vessel and not a language-related brain region. The intensity for stimulation was lower intensity so that participants still had the same sensation on the skin but no effective electrical currents were induced in the brain tissue.

Patients received 20 minutes of TMS or sham stimulation followed by 45 minutes of speech and language therapy for 10 days.

The TMS groups’ improvements were on average three times greater than the non-TMS group, researchers said. They used German language aphasia tests, which are similar to those in the United States, to measure language performance of the patients.

“TMS had the biggest impact on improvement in anomia, the inability to name objects, which is one of the most debilitating aphasia symptoms,” Thiel said.

Researchers, in essence, shut down the working part of the brain so that the stroke-affected side could relearn language. “This is similar to physical rehabilitation where the unaffected limb is immobilized with a splint so that the patients must use the affected limb during the therapy session,” Thiel said.

“We believe brain stimulation should be most effective early, within about five weeks after stroke, because genes controlling the recovery process are active during this time window,” he said.

"I feel like I have been dropped into my body. I know this is my voice and these are my memories, but they don’t feel like they belong to me."

It happened out of the blue. Louise Airey was 8 years old, off sick from school, when suddenly she felt like she had been dropped into her own body. “It’s just so difficult to verbalise what this feels like,” she says. “All of a sudden you’re hyper aware, and everything else in the world seems unreal, like a movie.”

She panicked, but told no one. The feeling soon passed but returned several times until, at the age of 19, a migraine triggered a sensation of being disconnected from the world that was to last 18 months. When she was in her 30s she was diagnosed with depersonalisation disorder – an altered sense of self with all-encompassing feelings of not occupying your own body, and detachment from your thoughts and actions. It has come and gone throughout her life, but since a traumatic pregnancy 20 months ago, these feelings have remained constant.

"Other people seem like robots," Airey says. "It’s like I’m watching a film, like I’m on my own in the centre of everything and nothing else is real. I’ll be speaking to my children and I’ll catch my voice talking and it seems really alien and foreign. It makes you feel very separated and lonely from everything, like you’re the only person that is real."

Not so rare

Depersonalisation disorder is not as rare as you might think, says Anthony David at King’s College London and the Maudsley Hospital: it may affect almost 1 per cent of the British population (Social Psychiatry and Psychiatric Epidemiology). We’ve all probably experienced mild versions of it at some point, in the unreal, spaced-out feeling you might get while severely jet-lagged or hung-over, for example. Now neuroscientists are beginning to uncover what goes wrong in those who persistently feel unreal. Their findings could tell us something about how we all form a sense of self, and potentially, bring a treatment for those who have the disorder.

The sense of self has much to do with our awareness of our physicality and how we interact with the outside world. The brain integrates all the information coming in from the external world and from internal sensations and forms a default setting of “this is me here and now”, says Nick Medford, who studies depersonalisation at the Brighton and Sussex Medical School, UK. “If that setting changes somehow, then you feel ‘not right’, in a way that might be very hard to put into words.”

There are probably several ways that change can occur, but Medford’s work is looking at the emotional detachment characteristic of depersonalisation. In people who have the disorder, areas of the brain that are key to emotion are much less active than normal. These people also show unusual autonomic physical responses to external stimuli, such as evocative images (Emotion Review).

David and his colleagues are also looking at why people with depersonalisation disorder report emotional “numbing” – the feeling that the world is somehow alien. They have found that some areas in the brain’s frontal lobes, which help keep emotions in check, are overactive, or too controlling.

Living the scream

One symptom related to this skewed brain activity is the sensation of all sounds competing against each other to be heard. It’s like living inside Edvard Munch’s painting The Scream, Airey says, which some critics have suggested is about depersonalisation. “The person and the landscape are screaming, you can’t get any peace.”

Another area of the brain that appears to be less responsive in depersonalisation is the anterior insula, responsible for integrating physical and emotional sensations. This might explain why sufferers don’t feel in touch with the world, Medford says.

It’s not only the outside world that seems strange, says Airey. The disorder makes it almost impossible for her to relate to herself. “Everything that you’re familiar with yourself – your thoughts, your memories – become alien,” she says. “Memories of things you’ve done don’t feel like they belong to you; it robs you of your past. I know rationally that they’re my thoughts, my voice, my memories, but they’re all wrong – that why it’s so frightening. It takes away the core of who you are.”

Airey says she would investigate any potential treatment. There is an epilepsy drug, Lamotrigine, that has shown some promise when combined with an antidepressant in trials. Transcranial magnetic stimulation – in which an electromagnet stimulates or suppresses neuronal activity – is also being explored by David’s team to retrain the depersonalised brain.

"Rationally knowing that I’m real, that these memories are real, that my voice is my own, but not feeling like they all belong to me is somehow worse than being away with fairies," Airey says. "It’s like I’m a sane person gone mad."

Mindscapes: The woman who was dropped into her body by Helen Thomson

Laser Light Zaps Away Cocaine Addiction

By stimulating one part of the brain with laser light, researchers at the National Institutes of Health (NIH) and the Ernest Gallo Clinic and Research Center at UC San Francisco (UCSF) have shown that they can wipe away addictive behavior in rats – or conversely turn non-addicted rats into compulsive cocaine seekers.

“When we turn on a laser light in the prelimbic region of the prefrontal cortex, the compulsive cocaine seeking is gone,” said Antonello Bonci, MD, scientific director of the intramural research program at the NIH’s National Institute on Drug Abuse (NIDA), where the work was done. Bonci is also an adjunct professor of neurology at UCSF and an adjunct professor at Johns Hopkins University.

Described this week in the journal Nature, the new study demonstrates the central role the prefrontal cortex plays in compulsive cocaine addiction. It also suggests a new therapy that could be tested immediately in humans, said Billy Chen of NIDA, the lead author of the study.

Any new human therapy would not be based on using lasers, but would most likely rely on electromagnetic stimulation outside the scalp, in particular a technique called transcranial magnetic stimulation (TMS). Clinical trials are now being designed to test whether this approach works, Chen added.

The High Cost of Cocaine Abuse

Cocaine abuse is a major public health problem in the United States today, and it places a heavy toll on society in terms of lost job productivity, lost earnings, cocaine-related crime, incarcerations, investigations, and treatment and prevention programs.

The human toll is even greater, with an estimated 1.4 million Americans addicted to the drug. It is frequently the cause of emergency room visits – 482,188 in 2008 alone – and it is a top cause of heart attacks and strokes for people under 35.

One of the hallmarks of cocaine addiction is compulsive drug taking – the loss of ability to refrain from taking the drug even if it’s destroying one’s life.

What makes the new work so promising, said Bonci, is that Chen and his colleagues were working with an animal model that mimics this sort of compulsive cocaine addiction. The animals, like human addicts, are more likely to make bad decisions and take cocaine even when they are conditioned to expect self-harm associated with it.

Electrophysiological studies involving these rats have shown that they have extremely low activity in the prefrontal cortex – a brain region fundamental for impulse control, decision making and behavioral flexibility. Similar studies that imaged the brains of humans have shown the same pattern of low activity in this region in people who are compulsively addicted to cocaine.

Altering Brain Activity with a Laser

To test whether altering the activity in this brain region could impact addiction, Chen and his colleagues employed a technique called optogenetics to shut the activity on and off using a laser.

First they took light-sensitive proteins called rhodopsins and used genetic engineering to insert them into neurons in the rat’s prefrontal cortex. Activating this region with a laser tuned to the rhodopsins turned the nerve cells on and off.

Turning on these cells wiped out the compulsive behavior, while switching them off turned the non-addicted ones into addicted, researchers found.

What’s exciting, said Bonci, is that there is a way to induce a similar activation of the prelimbic cortex in people through a technique called transcranial magnetic stimulation (TMS), which applies an external electromagnetic field to the brain and has been used as a treatment for symptoms of depression.

Bonci and his colleagues plan to begin clinical trials at NIH in which they will use this technique a few sessions a week to stimulate the prefrontal cortex in people who are addicted to cocaine and see if they can restore activity to that part of the brain and help them avoid taking the drug.