Personal reflection triggers increased brain activity during depressive episodes

Research by the University of Liverpool has found that people experiencing depressive episodes display increased brain activity when they think about themselves.

Using functional magnetic resonance imaging (fMRI) brain imaging technologies, scientists found that people experiencing a depressive episode process information about themselves in the brain differently to people who are not depressed.

British Queen

Researchers scanned the brains of people in major depressive episodes and those that weren’t whilst they chose positive, negative and neutral adjectives to describe either themselves or the British Queen -  a figure significantly removed from their daily lives but one that all participants were familiar with.

Professor Peter Kinderman, Head of the University’s Institute of Psychology, Health and Society, said: “We found that participants who were experiencing depressed mood chose significantly fewer positive words and more negative and neutral words to describe themselves, in comparison to participants who were not depressed.

“That’s not too surprising, but the brain scans also revealed significantly greater blood oxygen levels in the medial superior frontal cortex – the area associated with processing self-related information – when the depressed participants were making judgments about themselves.

“This research leads the way for further studies into the psychological and neural processes that accompany depressed mood. Understanding more about how people evaluate themselves when they are depressed, and how neural processes are involved could lead to improved understanding and care.”

Dr May Sarsam, from the Mersey Care NHS Trust, said:  “This study explored the difference in medical and psychological theories of depression.  It showed that brain activity only differed when depressed people thought about themselves, not when they thought about the Queen or when they made other types of judgements, which fits very well with the current psychological theory.

Equally important

“Thought and neurochemistry should be considered as equally important in our understanding of mental health difficulties such as depression.”

Depression is associated with extensive negative feelings and thoughts.  Nearly one-fifth of adults experience anxiety or depression, with the conditions affecting a higher proportion of women than men.

The research, in collaboration with the Mersey Care NHS Trust and the Universities of Manchester, Edinburgh and Lancaster, is published in PLOS One.

A new way to monitor induced comas

After suffering a traumatic brain injury, patients are often placed in a coma to give the brain time to heal and allow dangerous swelling to dissipate. These comas, which are induced with anesthesia drugs, can last for days. During that time, nurses must closely monitor patients to make sure their brains are at the right level of sedation — a process that MIT’s Emery Brown describes as “totally inefficient.”

“Someone has to be constantly coming back and checking on the patient, so that you can hold the brain in a fixed state. Why not build a controller to do that?” says Brown, the Edward Hood Taplin Professor of Medical Engineering in MIT’s Institute for Medical Engineering and Science, who is also an anesthesiologist at Massachusetts General Hospital (MGH) and a professor of health sciences and technology at MIT.

Brown and colleagues at MGH have now developed a computerized system that can track patients’ brain activity and automatically adjust drug dosages to maintain the correct state. They have tested the system  — which could also help patients who suffer from severe epileptic seizures — in rats and are now planning to begin human trials.

Maryam Shanechi, a former MIT grad student who is now an assistant professor at Cornell University, is the lead author of the paper describing the computerized system in the Oct. 31 online edition of the journal PLoS Computational Biology.

Tracking the brain

Brown and his colleagues have previously analyzed the electrical waves produced by the brain in different states of activity. Each state — awake, asleep, sedated, anesthetized and so on — has a distinctive electroencephalogram (EEG) pattern.

When patients are in a medically induced coma, the brain is quiet for up to several seconds at a time, punctuated by short bursts of activity. This pattern, known as burst suppression, allows the brain to conserve vital energy during times of trauma.

As a patient enters an induced coma, the doctor or nurse controlling the infusion of anesthesia drugs tries to aim for a particular number of “bursts per screen” as the EEG pattern streams across the monitor. This pattern has to be maintained for hours or days at a time.

“If ever there were a time to try to build an autopilot, this is the perfect time,” says Brown, who is a professor in MIT’s Department of Brain and Cognitive Sciences. “Imagine that you’re going to fly for two days and I’m going to give you a very specific course to maintain over long periods of time, but I still want you to keep your hand on the stick to fly the plane. It just wouldn’t make sense.”

To achieve automated control, Brown and colleagues built a brain-machine interface — a direct communication pathway between the brain and an external device that typically assists human cognitive, sensory or motor functions. In this case, the device — an EEG system, a drug-infusion pump, a computer and a control algorithm — uses the anesthesia drug propofol to maintain the brain at a target level of burst suppression.

The system is a feedback loop that adjusts the drug dosage in real time based on EEG burst-suppression patterns. The control algorithm interprets the rat’s EEG, calculates how much drug is in the brain, and adjusts the amount of propofol infused into the animal second-by-second.

The controller can increase the depth of a coma almost instantaneously, which would be impossible for a human to do accurately by hand. The system could also be programmed to bring a patient out of an induced coma periodically so doctors could perform neurological tests, Brown says.

This type of system could take much of the guesswork out of patient care, says Sydney Cash, an associate professor of neurology at Harvard Medical School.

“Much of what we do in medicine is making educated guesses as to what’s best for the patient at any given time,” says Cash, who was not part of the research team. “This approach introduces a methodology where doctors and nurses don’t need to guess, but can rely on a computer to figure out — in much more detail and in a time-efficient fashion — how much drug to give.”

Monitoring anesthesia

Brown believes that this approach could easily be extended to control other brain states, including general anesthesia, because each level of brain activity has its own distinctive EEG signature.

“If you can quantitatively analyze each state’s signature in real time and you have some notion of how the drug moves through the brain to generate those states, then you can build a controller,” he says.

There are currently no devices approved by the U.S. Food and Drug Administration (FDA) to control general anesthesia or induced coma. However, the FDA has recently approved a device that controls sedation not using EEG readings.

The MIT and MGH researchers are now preparing applications to the FDA to test the controller in humans.

Baby brains are tuned to the specific actions of others

Imitation may be the sincerest form of flattery for adults, but for babies it’s their foremost tool for learning. As renowned people-watchers, babies often observe others demonstrate how to do things and then copy those body movements. It’s how little ones know, usually without explicit instructions, to hold a toy phone to the ear or guide a spoon to the mouth.

Now researchers from the University of Washington and Temple University have found the first evidence revealing a key aspect of the brain processing that occurs in babies to allow this learning by observation.

The findings, published online Oct. 30 by PLOS ONE, are the first to show that babies’ brains showed specific activation patterns when an adult performed a task with different parts of her body. When 14-month-old babies simply watched an adult use her hand to touch a toy, the hand area of the baby’s brain lit up. When another group of infants watched an adult touch the toy using only her foot, the foot area of the baby’s brain showed more activity.

"Babies are exquisitely careful people-watchers, and they’re primed to learn from others," said Andrew Meltzoff, co-author and co-director of the UW Institute for Learning & Brain Sciences. "And now we see that when babies watch someone else, it activates their own brains. This study is a first step in understanding the neuroscience of how babies learn through imitation."

The study took advantage of how the brain is organized. The sensory and motor area of the cortex, the outer portion of the brain known for its creased appearance, is arranged by body part with each area of the body represented in identifiable neural real estate. Prick your finger, stick out your tongue, or kick a ball and distinct areas of the brain light up according to a somatotopic map.

Other studies show that adults show this somatotopic brain activation while watching someone else use different body parts, suggesting that adults understand the actions of others in relation to their own bodies. The researchers wondered whether the same would be true in babies.

The 70 infants in the study wore electroencephalogram, or EEG, caps with embedded sensors that detected brain activity in the regions of the cortex that respond to movement or touch of the feet and hands. Sitting on a parent’s lap, each baby watched as an experimenter touched a toy placed on a low table between the baby and the experimenter.

The toy had a clear plastic dome and was mounted on a sturdy base. When the experimenter pressed the dome with her hand or foot, music played and confetti in the dome spun. The experimenter repeated the action – taking breaks after every four presses – until the baby lost interest.

"Our findings show that when babies see others produce actions with a particular body part, their brains are activated in a corresponding way," said Joni Saby, lead author and a psychology graduate student at Temple University in Philadelphia. "This mapping may facilitate imitation and could play a role in the baby’s ability to then produce the same actions themselves."

One of the basics for babies to learn is how to copy what they see adults do. In other words, they must first know that it is indeed their hand and not their foot, mouth or other body part that is needed.

The new study shows that babies’ brains are organized in a somatotopic way that helps crack the interpersonal code. The connection between doing and seeing actions maps hand to hand, foot to foot, all before they can name those body parts through language.

"The reason this is exciting is that it gives insight into a crucial aspect of imitation," said co-author Peter Marshall, an associate psychology professor at Temple University. "To imitate the action of another person, babies first need to register what body part the other person used. Our findings suggest that babies do this in a particular way by mapping the actions of the other person onto their own body."

Meltzoff added, “The neural system of babies directly connects them to other people, which jump-starts imitation and social-emotional connectedness and bonding. Babies look at you and see themselves.”

Brain stimulation affects compliance with social norms

Neuroeconomists at the University of Zurich have identified a specific brain region that controls compliance with social norms. They discovered that norm compliance is independent of knowledge about the norm and can be increased by means of brain stimulation.

How does the human brain control compliance with social norms? The biological mechanisms that underlie norm compliance are still poorly understood. In a new study, Christian Ruff, Giuseppe Ugazio, and Ernst Fehr from the University of Zurich show that the lateral prefrontal cortex plays a central role in norm compliance.

Prefrontal cortex controls norm behavior

For the study, 63 participants took part in an experiment in which they received money and were asked to decide how much of it they wanted to share with an anonymous partner. A prevalent fairness norm in Western cultures dictates that the money should be evenly split between the two players. However, this contrasts with the participants’ self-interest to keep as much money as possible for themselves. In another experiment, the participants were faced with the same decision, but knew in advance that they could be punished by the partner for an unfair proposal.

By means of a technique called “transcranial direct current stimulation,” which sends weak and painless electric currents through the skull, the excitability of specific brain regions can be modulated. During this experiment, the scientists used this technique to increase or decrease neural activity at the front of the brain, in the right lateral prefrontal cortex. Christian Ruff, Professor of Neuroeconomics and Decision Neuroscience at the University of Zurich, said: “We discovered that the decision to follow the fairness norm, whether voluntarily or under threat of sanctions, can be directly influenced by neural stimulation in the prefrontal cortex.”

Brain stimulation affects normative behavior

When neural activity in this part of the brain was increased via stimulation, the participants’ followed the fairness norm more strongly when sanctions were threatened, but their voluntary norm compliance in the absence of possible punishments decreased. Conversely, when the scientists decreased neural activity, participants followed the fairness norm more strongly on a voluntary basis, but complied less with the norm when sanctions were threatened. Moreover, neural stimulation influenced the participants’ behavior, but it did not affect their perception of the fairness norm. It also did not alter their expectations about whether and how much they would be punished for violating the norm.

"We found that the brain mechanism responsible for compliance with social norms is separate from the processes that represent one’s knowledge and beliefs about the social norm," says Ernst Fehr, Chairman of the Department of Economics at the University of Zurich. "This could have important implications for the legal system as the ability to distinguish between right and wrong may not be sufficient for the ability to comply with social norms." Christian Ruff adds: "Our findings show that a socially and evolutionarily important aspect of human behavior depends on a specific neural mechanism that can be both up- and down-regulated with brain stimulation."

Literature:

Christian C. Ruff, Giuseppe Ugazio und Ernst Fehr. Changing Social Norm Compliance With Noninvasive Brain Stimulation. Science. October 3, 2013.

(Image: iStockphoto)

Get the picture? New high-​​res images show brain activity like never before

Covert operations: Your brain digitally remastered for clarity of thought

Neurofeedback can enhance the signal-to-noise ratio in thought, enabling a sharper focus on tasks—and a better understanding of brain-computer interfaces.

The sweep of a needle across the grooves of a worn vinyl record carries distinct sounds: hisses, scratches, even the echo of skips. For many years, though, those yearning to hear Frank Sinatra sing “Fly Me to the Moon” have been able to listen to his light baritone with technical clarity, courtesy of the increased signal-to-noise ratio of digital remasterings.

Now, with advances in neurofeedback techniques, the signal-to-noise ratio of the brain activity underlying our thoughts can be remastered as well, according to the recent discovery of a research team led by Stephen LaConte, an assistant professor at the Virginia Tech Carilion Research Institute.

LaConte and his colleagues specialize in real-time functional magnetic resonance imaging, a relatively new technology that can convert thought into action by transferring noninvasive measurements of human brain activity into control signals that drive physical devices and computer displays in real time. Crucially, for the ultimate goal of treating disorders of the brain, this rudimentary form of mind reading enables neurofeedback.

“Our brains control overt actions that allow us to interact directly with our environments, whether by swinging an arm or singing an aria,” LaConte said. “Covert mental activities, on the other hand—such as visual imagery, inner language, or recollections of the past—can’t be observed by others and don’t necessarily translate into action in the outside world.”

But, LaConte added, brain–computer interfaces now enable us to eavesdrop on previously undetectable mental activities.

In the recent study, the scientists used whole-brain, classifier-based real-time functional magnetic resonance imaging to understand the neural underpinnings of brain–computer interface control. The research team asked two dozen subjects to control a visual interface by silently counting numbers at fast and slow rates. For half the tasks, the subjects were told to use their thoughts to control the movement of the needle on the device they were observing; for the other tasks, they simply watched the needle.

The scientists discovered a feedback effect that LaConte said he had long suspected existed but had found elusive: the subjects who were in control of the needle achieved a better whole-brain signal-to-noise ratio than those who simply watched the needle move. “When the subjects were performing the counting task without feedback, they did a pretty good job,” LaConte said. “But when they were doing it with feedback, we saw increases in the signal-to-noise ratio of the entire brain. This improved clarity could mean that the signal was sharpening, the noise was dropping, or both. I suspect the brain was becoming less noisy, allowing the subject to concentrate on the task at hand.”

The scientists also found that the act of controlling the computer–brain interface led to an increased classification accuracy, which corresponded with improvements in the whole-brain signal-to-noise ratio.

This enhanced signal-to-noise ratio, LaConte added, carries implications for brain rehabilitation. “When people undergoing real-time brain scans get feedback on their own brain activity patterns, they can devise ways to exert greater control of their mental processes,” LaConte said. “This, in turn, gives them the opportunity to aid in their own healing. Ultimately, we want to use this effect to find better ways to treat brain injuries and psychiatric and neurological disorders.”

“Dr. LaConte’s discovery represents a milestone in the development of noninvasive brain imaging approaches with potential for neurorehabilitation,” said Michael Friedlander, executive director of the Virginia Tech Carilion Research Institute and a neuroscientist who specializes in brain plasticity. “This research carries implications for people whose brains have been damaged, such as through traumatic injury or stroke, in ways that affect the motor system—how they walk, move an arm, or speak, for example. Dr. LaConte’s innovations with real-time functional brain imaging are helping to set the stage for the future, for capturing covert brain activity and creating better computer interfaces that can help people retrain their own brains.”