Why does the brain remember dreams?

Some people recall a dream every morning, whereas others rarely recall one. A team led by Perrine Ruby, an Inserm Research Fellow at the Lyon Neuroscience Research Center (Inserm/CNRS/Université Claude Bernard Lyon 1), has studied the brain activity of these two types of dreamers in order to understand the differences between them. In a study published in the journal Neuropsychopharmacology, the researchers show that the temporo-parietal junction, an information-processing hub in the brain, is more active in high dream recallers. Increased activity in this brain region might facilitate attention orienting toward external stimuli and promote intrasleep wakefulness, thereby facilitating the encoding of dreams in memory.

The reason for dreaming is still a mystery for the researchers who study the difference between “high dream recallers,” who recall dreams regularly, and “low dream recallers,” who recall dreams rarely. In January 2013 (work published in the journal Cerebral Cortex), the team led by Perrine Ruby, Inserm researcher at the Lyon Neuroscience Research Center, made the following two observations: “high dream recallers” have twice as many time of wakefulness during sleep as “low dream recallers” and their brains are more reactive to auditory stimuli during sleep and wakefulness. This increased brain reactivity may promote awakenings during the night, and may thus facilitate memorisation of dreams during brief periods of wakefulness.

In this new study, the research team sought to identify which areas of the brain differentiate high and low dream recallers. They used Positron Emission Tomography (PET) to measure the spontaneous brain activity of 41 volunteers during wakefulness and sleep. The volunteers were classified into 2 groups: 21 “high dream recallers” who recalled dreams 5.2 mornings  per week in average, and 20 “low dream recallers,” who reported 2 dreams per month in average. High dream recallers, both while awake and while asleep, showed stronger spontaneous brain activity in the medial prefrontal cortex (mPFC) and in the temporo-parietal junction (TPJ), an area of the brain involved in attention orienting toward external stimuli.

Predicting Who Will Have Chronic Pain

Abnormalities in brain axons predispose people to chronic back pain after injury

Abnormalities in the structure of the brain predispose people to develop chronic pain after a lower back injury, according to new Northwestern Medicine® research. The findings could lead to changes in the way physicians treat patients’ pain.

Most scientists and clinicians have assumed chronic back pain stems from the site of the original injury.

“We’ve found the pain is triggered by these irregularities in the brain,” said A. Vania Apkarian, senior author of the study and a professor of physiology at Northwestern University Feinberg School of Medicine. “We’ve shown abnormalities in brain structure connections may be enough to push someone to develop chronic pain once they have an injury.”

Based on MRI brain scans of people who had a new lower back injury, Northwestern scientists could predict with about 85 percent accuracy which patients’ pain would persist. The predictor was a specific irregularity or marker the scientists identified in the axons, pathways in the brain’s white matter that connect brain cells so they can communicate with each other.

The findings provide a new view of treating chronic pain, which affects nearly 100 million Americans and costs up to $635 billion a year to treat.

“We think the people who are vulnerable need to be treated aggressively with medication early on to prevent their pain from becoming chronic,” Apkarian said. “Last year, we showed people who take medication early on had a better chance of recovering. Medication does help.” Apkarian also is a member of the Robert H. Lurie Comprehensive Cancer Center of Northwestern University.

The research, funded by the National Institutes of Health, was published Sept. 16 in the journal Pain.

Brain abnormalities have been observed in other long-term chronic pain conditions. Apkarian’s study is the first to show brain structure abnormalities are a marker of a predisposition to the chronic pain, not a result of living with it.

The lead author of the study is Ali Mansour, M.D., formerly a postdoctoral fellow in Apkarian’s lab.

Apkarian’s research focuses on the relationship between chronic pain and the brain. One of his previous studies showed chronic pain patients lose gray matter volume over time.

Chronic pain is one of the most expensive health care conditions in the U.S. and takes an enormous toll on quality of life, yet there still is not a scientifically validated therapy for the condition. Lower back pain represents 28 percent of all causes of pain in the U.S.; about 23 percent of these patients suffer long-term pain.

The abnormalities identified in the study were found in multiple white matter axon bundles, some surrounding the nucleus accumbens and medial prefrontal cortex, two brain regions involved in processing emotion and pain. Last year, the Apkarian group showed that the physiological properties of these two regions identify which patients will persist with back pain. The new results identify a pre-existing culprit for these physiological responses to the injury.

“The brain abnormalities exist in the general population, but only those people with a back injury go on to develop the chronic pain,” Apkarian said.

For the study, Apkarian and his colleagues scanned the brains of 46 people who had an episode of lower back pain for at least four weeks and had not experienced any pain for at least one year before that. Their pain had to be rated at least five out of 10 on a pain scale for them to be included in the study.

Scientists followed the patients for a year, scanning their brains at the onset of study and one year later. After a year about half of them had improved, regardless of whether they took anything to treat the pain, and half of them continued to have pain. Those with the persistent pain had the same structural abnormalities in their white matter at the onset of the injury and after one year.

“The abnormality makes them vulnerable and predisposes them to enhanced emotional learning that then amplifies the pain and makes it more emotionally significant,” Apkarian said.

“Pain is becoming an enormous burden on the public,” said Linda Porter, the pain policy advisor at National Institute of Neurological Disorders and Stroke (NINDS) and a leader of the National Institutes of Health (NIH) Pain Consortium. “The U.S. government recently outlined steps to reduce the future burden of pain through broad-ranging efforts, including enhanced research. This study is a good example of the kind of innovative research we hope will reduce chronic pain, which affects a huge portion of the population.”

(Image: Shutterstock)

Human Emotion: We Report Our Feelings in 3-D

Like it or not and despite the surrounding debate of its merits, 3-D is the technology du jour for movie-making in Hollywood. It now turns out that even our brains use 3 dimensions to communicate emotions.

According to a new study published in Biological Psychiatry, the human report of emotion relies on three distinct systems: one system that directs attention to affective states (“I feel”), a second system that categorizes these states into words (“good”, “bad”, etc.); and a third system that relates the intensity of affective responses (“bad” or “awful”?).

Emotions are central to the human experience. Whether we are feeling happy, sad, afraid, or angry, we are often asked to identify and report on these feelings. This happens when friends ask us how we are doing, when we talk about professional or personal relationships, when we meditate, and so on. In fact, the very commonness and ease of reporting what we are feeling can lead us to overlook just how important such reports are - and how devastating the impairment of this ability may be for individuals with clinical disorders ranging from major depression to schizophrenia to autism spectrum disorders.

Progress in brain science has steadily been shedding light on the circuits and processes that underlie mood states. One of the leaders in this effort, Dr. Kevin Ochsner, Director of the Social Cognitive Neuroscience Lab at Columbia University, studies the neural bases of social, cognitive and affective processes. In this new study, he and his team set out to study the processes involved in constructing self-reports of emotion, rather than the effects of the self-reports or the emotional states themselves for which there is already much research.

To accomplish this, they recruited healthy participants who underwent brain scans while completing an experimental task that generated a self-report of emotion. This effort allowed the researchers to examine the neural architecture underlying the emotional reports.

“We find that the seemingly simple ability is supported by three different kinds of brain systems: largely subcortical regions that trigger an initial affective response, parts of medial prefrontal cortex that focus our awareness on the response and help generate possible ways of describing what we are feeling, and a part of the lateral prefrontal cortex that helps pick the best words for the feelings at hand,” said Ochsner.

“These findings suggest that self-reports of emotion - while seemingly simple - are supported by a network of brain regions that together take us from an affecting event to the words that make our feelings known to ourselves and others,” he added. “As such, these results have important implications for understanding both the nature of everyday emotional life - and how the ability to understand and talk about our emotions can break down in clinical populations.”

Dr. John Krystal, Editor of Biological Psychiatry, said, “It is critical that we understand the mechanisms underlying the absorption in emotion, the valence of emotion, and the intensity of emotion. In the short run, appreciation of the distinct circuits mediating these dimensions of emotional experience helps us to understand how brain injury, stroke, and tumors produce different types of mood changes. In the long run, it may help us to better treat mood disorders.”

Mental picture of others can be seen using fMRI

It is possible to tell who a person is thinking about by analyzing images of his or her brain. Our mental models of people produce unique patterns of brain activation, which can be detected using advanced imaging techniques according to a study by Cornell University neuroscientist Nathan Spreng and his colleagues.

"When we looked at our data, we were shocked that we could successfully decode who our participants were thinking about based on their brain activity," said Spreng, assistant professor of human development in Cornell’s College of Human Ecology.

Understanding and predicting the behavior of others is a key to successfully navigating the social world, yet little is known about how the brain actually models the enduring personality traits that may drive others’ behavior, the authors say. Such ability allows us to anticipate how someone will act in a situation that may not have happened before.

To learn more, the researchers asked 19 young adults to learn about the personalities of four people who differed on key personality traits. Participants were given different scenarios (i.e. sitting on a bus when an elderly person gets on and there are no seats) and asked to imagine how a specified person would respond. During the task, their brains were scanned using functional magnetic resonance imaging (fMRI), which measures brain activity by detecting changes in blood flow.

They found that different patterns of brain activity in the medial prefrontal cortex (mPFC) were associated with each of the four different personalities. In other words, which person was being imagined could be accurately identified based solely on the brain activation pattern.

The results suggest that the brain codes the personality traits of others in distinct brain regions and this information is integrated in the medial prefrontal cortex (mPFC) to produce an overall personality model used to plan social interactions, the authors say.

"Prior research has implicated the anterior mPFC in social cognition disorders such as autism and our results suggest people with such disorders may have an inability to build accurate personality models," said Spreng. "If further research bears this out, we may ultimately be able to identify specific brain activation biomarkers not only for diagnosing such diseases, but for monitoring the effects of interventions."

Science Explains Instant Attraction

How do you know when you’re attracted to a new face? Thank your medial prefrontal cortex, a brain region now discovered to play a major role in romantic decision-making.

Different parts of this region, which sits near the front of the brain, make a snap judgment about physical attraction and about whether the person is Mr. or Ms. Right — all within milliseconds of seeing a new face, a new study from Ireland finds.

The research is the first to use real-world dating to examine how the brain makes fast romantic judgments.

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