Monday, May 7, 2012

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Thursday, April 12, 2012

CNS 2012 in the News

Check out coverage of CNS 2012 in the news (last updated April 23, 2012):

Brain scan foretells who will fold under pressure,” Science News, April, 2, 2012.

Accentuating the positive memories for sleep, Science Codex, April 2, 2012.
Accentuating the positive memories for sleep, Medical Xpress, April 2, 2012.

Jolt to brain aids language recovery, Science News, April 2, 2012.

How does our brain respond to food? Doctor Tipster, April 3, 2012.

Brains of anorexics, obese wired differently: Study
, QMI agency, April 3, 2012.

Breakthrough treatment incoming forstroke patients?, Spire Healthcare, April 3, 2012.

Extreme eaters show abnormal brain activity, Science News, April 4, 2012.

How Brain Networks Influence Eating Disorders, PsychCentral, April 4, 2012.

Sleep May Protect Positive Memories,Study Finds, The Huffington Post, April 9, 2012.

Inquiring Minds: Exercise and Mental Recall, BU Today, April 19, 2012.

Ramachandran’s Lab Looks Into Whether You Can Be a Man in the Morning and a Woman at Night, Scientific American blog, April 19, 2012.

"Stimulating the Brain to Improve Speech, Memory, Numerical Abilities," forthcoming in 
Stroke Recovery News, August 2012.

Tuesday, April 3, 2012

From Flavors to Food Cues: Our Brains on Food

The old saying "The first taste is always with your eyes" is neurologically true, said Kyle Simmons of the Laureate Institute for Brain Research at the CNS 2012 symposium session this morning about our brains on food. The session highlighted a variety of interesting approaches to understanding and responding to the rising trend of obesity.

Whenever we are presented with food or even just the idea of it, our brains automatically start thinking about how it will taste and how eating the item will make us feel, Simmons said. The insular cortex, he reported, is key in this information retrieval. Just going up to the frozen yogurt station and looking at all the options -- the flavors, the bowl size, the toppings -- you will automatically associate the labels with the reward properties of the food.

In this "obesogenic world," how we respond to such food cues, may very well predict our weight, according to Susan Carnell of the New York Obesity Nutrition Center.  Her research has tested responses to both visual and auditory food cues, including looking at brain responses in the fMRI scanner. Some of the results have shown that obese versus lean people have greater activation of brain areas associated with motivation, emotion and decision-making in response to high-calorie versus low-calorie foods. And in those individuals, there is an increased desire to eat.

Dana Small further explored the role of calories in how we learn about flavors. She and colleagues have worked to replicate in humans a study that showed that rats show preference for flavors that they have learned deliver glucose (calories) to them. In her flavor lab at Yale University, they created 5 novel drinks, all different colors, and all non-caloric. In their experiment which involved fMRI scanning and physiological testing, the researchers at some point added maltodextrin to one of the drinks to make it caloric. (They ensured through a series of tests that participants could not tell the caloric from non-caloric).

The results? Healthy people learned to prefer the drink with 112 calories versus the drink with 0 calories. Changes in how they rated the drinks were associated with responses in the insular cortex, which was inversely related to percent body fat. The more obese, the less the response in the insular cortex, which has implications for how increased body weight changes neurological conditions such as interfering with dopamine signaling.

Laura Holsen of Harvard Medical School and Brigham and Women's Hospital rounded out the talks with discussion of eating behavior at the extreme -- from anorexia nervosa to a genetic condition that causes compulsive overeating called Prader-Willi syndrome. She highlighted the different neurological circuitry associated with the spectrum of food intake. You can read more about Holsen's and Simmon's work in a press release issued today.

Monday, April 2, 2012

Back to Our Youth: Math-Proficient Children and Risk-Taking Adolescents

Attendees of today's slide session at CNS 2012 on thinking and decision-making had a rare treat for a scientific meeting: getting to watch a clip of Sesame Street. Elmo was singing to 7 swimming fish about, you guessed it, the number 7. It was an example of the type of educational video that introduces young children to numerical concepts – a topic being explored from the cognitive neuroscience perspective by Robert Emerson and colleagues at the University of Rochester.

Emerson described an experiment that involved looking at brain connectivity in 4- to 11-year-olds that relates to processing numbers. The children were asked to sort through faces, shapes, words, and numbers while in an fMRI scanner to help isolate the parts of the brain that respond during numerical matching: the prefrontal cortex and intraparietal sulcus (frontal and parietal regions). The children then watched a video about math, like the one of Elmo, while researchers measured the connectivity in those regions of the brain. Separately, the researchers tested the children's math IQ and general IQ.

The results showed that the connectivity in the parts of the brain involved in the number-matching successfully predicted the children's math ability. The frontal-parietal connectivity was “specific to math ability,” Emerson stressed, as his study found no correlation between connectivity in those parts of the brain and general IQ, age, reaction time, or any other factor. Researchers also tested if the same relationship existed between connectivity in the parts of the brain associated with face matching and mathematics but found no correlation.

From childhood math to risk-taking adolescents

In the same slide session, we moved from the innocence of childhood learning to the not-so-innocent world of adolescent risk-taking. As Eva Tezler of the University of California, Los Angeles, discussed, much research has documented how adolescents are more prone to morbidity and mortality than younger children due to riskier behavior, including alcohol and drug abuse, unprotected sex, risky driving, and accidents. Research in adults has documented how sleep deprivation can diminish cognitive functions, such as attention control and emotional regulation. With sleep deprivation endemic among adolescents, she and colleagues set out to see if there was a neurological relationship between inadequate sleep and risk-taking in adolescents.

The researchers had 46 adolescents aged 14 to 16 years take the Balloon Analogue Risk Task (BART) while in an fMRI scanner. In the test, subjects can inflate a balloon to larger and larger sizes for monetary compensation, but with each increase in reward comes a greater risk that the balloon will explode. If the balloon explodes before the subjects “cash out,” they do not get any money.

Tezler's team coupled the results of that test with information about the adolescents' sleep behavior from the Pittsburgh Sleep Quality Index, which measures sleep quality over the previous month. In general, adolescents with poorer sleep were more likely to inflate the balloons and explode them more on the BART test.

When taking risks to inflate the balloon, those adolescents showed decreased activation in the insula, a brain region involved in risk-taking. Those who cashed out despite poorer sleep showed increased activation in both the insula, as well as dorsolateral prefrontal cortex (DLPFC), a brain region involved in cognitive control.

The sleep-deprived adolescents also had greater self-reported risk-taking and a more positive view of risk-taking. The findings show that adolescents may need to exert more cognitive control to make the decision to stop taking risks.

Stimulating the Brain to Improve Speech, Memory, Numerical Abilities

Speaking to a packed Grand Ballroom at the Palmer House Hotel in Chicago this morning, Roi Cohen Kadosh opened the session on non-invasive brain stimulation by explaining that it will not just focus on one single cognitive function but several -- including motor skills, memory, speech, and numerical cognition. And the research spans a range of populations, including young, healthy adults, people with degenerative diseases, and neurological patients.

The research, which Cohen Kadosh has called "futuristic," involves researchers applying weak electrical currents to the head via electrodes for a short period of time, for example 20 minutes. The currents pass through the skull and either excite the neurons or suppress them, with the goal to enhance or alter some cognitive ability. Subjects usually feel only a slight tingling for less than 30 seconds, and the effects can last for up to 12 months.

“Non-invasive brain stimulation can allow painless, inexpensive, and apparently safe method for cognitive improvement with with potential long-term efficacy,” said Cohen Kadosh of the University of Oxford in a statement released today for the CNS 2012 meeting in Chicago. Read the full press release to learn about how this technique is being applied to stroke patients to improve speech therapy, to Alzheimer's and Parkinson's patients to improve memory, and to people with low numerical abilities to improve their math skills.


Sunday, April 1, 2012

Emotion's Double-Edged Sword: When We Remember the Forest for the Trees or Not

You are driving to work when a car suddenly crosses into your lane, careens toward your car, and narrowly misses you, slamming into a wall instead. Your heart is racing, and you will surely remember this incident for a while, but will you remember anything else happening at the time? Will you remember the song playing on the radio or other cars that were nearby? Talks today at the CNS meeting in Chicago explored some of the latest research seeking to understand how such emotional events affect our memory.

In general, emotional arousal enhances our memory of positive or negative information. Sometimes, however, emotional arousal can help, while other times it can hinder memory of neutral information processed before, during, or after the emotional arousal. Mara Mather of the University of California discussed a method she and her research team have developed to better understand and predict when emotional arousal will enhance or impair memory of such neutral items.

In the “arousal-based competition” model, when multiple stimuli are present, they compete for neural representation, Mather explained. Changing how we are introduced to the neutral items or how we perceive their importance will determine how well we remember them.

For example, in one study, Mather's team showed people an image with several letters of the alphabet, a few of which were high contrast against the background while the rest had less contrast – to give greater salience to the high-contrast letters. They then blasted people with either a negative stimuli – the sound of bees buzzing – or a neutral one – cows mooing, to see which letters people would recall best. The negative sound enhanced short-term recall of the high contrast letters and impaired contrast for the low-contrast letters, relative to the neutral sound.

This is one example, Mather said, of how the arousal-based competition method favors high-priority information – in this case the high-contrast letters. Similarly, researchers can manipulate recall of neutral items by instructing subjects to specifically remember the item – thereby conferring high priority in processing that information.

Elizabeth Kensinger followed Mather's talk by discussing the possible neural mechanisms that control when we remember an item versus the context. Her team has done a series of experiments that involve placing a negative (e.g. dead cat), neutral (e.g. tumbleweed), or positive (e.g. hot-air balloon) image on a neutral background (open prairie). They wanted to map not only whether people remembered the items or the background but also which brain regions were activated when they first viewed the images, so they put people in MRI scanners while looking at different images for short (5 seconds) time period and then tested their recall.

The researchers found that activity in the amygdala and orbitofrontal cortex corresponded well with good memory for items but not backgrounds, while activity in areas of the brain associated with visual processing and attention led to forgetting the background. Generally, high emotional arousal from either positive or negative stimuli leads to a tradeoff between whether we remember an item or the background. The activity within an emotional memory region of the brain, she stressed, leads to selective memory benefits, not enhancement for all details.

There are some exceptions to this rule, Kensinger said, particularly in high-stress situations. There are also some individual differences in emotional processing of memories. For example, she found that those better at exerting control over their actions are less likely to show tradeoffs based on stimulus – such people can remember neutral backgrounds better but nothing can change the enhancement of memory for high-arousal items.

Rounding out the talks were interesting perspectives from Florin Dolcos, of the University of Illinois at Urbana-Champaign, on how emotional distraction can both impair working memory (e.g. make it harder to talk on a cell phone when a car is crashing nearby) and enhance longer-term memory of the event itself, as well as from Guillen Fernandez of Radboud University Nijmegen on neural processes underlying how we respond to stress. Taken together, the talks provided a robust perspective on the state of understanding how emotions can either enhance or inhibit attention, perception, and memory – as Dolcos said, the “double-edge sword” of emotion and cognition. All the speakers addressed how their work can apply to not only healthy adults but also those with disorders such as post-traumatic stress disorder.

Accentuating the Positive Memories for Sleep

CNS 2012 has more than 900 posters on a variety of cognitive neuroscience topics. Check out this recent press release that highlights just a couple of posters    on the effects of sleep on positive memories (including one being presented at Poster Session D tonight):

Sleep plays a powerful role in preserving our memories. But while recent research shows that wakefulness may cloud memories of negative or traumatic events, a new study has found that wakefulness also degrades positive memories. Sleep, it seems, protects positive memories just as it does negative ones, and that has important implications for the treatment of post-traumatic stress disorder.

“The study of how sleep helps us remember and process emotional information is still young,” says Alexis Chambers of the University of Notre Dame. Past work has focused on the role of negative memories for sleep, in particular how insomnia is a healthy biological response for people to reduce negative memories and emotions associated with a traumatic event.

Two new studies presented this week at a meeting of cognitive neuroscientists in Chicago are exploring the flip side: how sleep treats the positive. “Only if we investigate all the possibilities within this field will we ever fully understand the processes underlying our sleep, memory, and emotions,” Chambers says. ... Read full press release.


Both studies – “Effects of Sleep on Memory and Reactivity for PositiveEmotional Pictures,” by Rebecca Spencer et al., and “LaughYourself to Sleep: The Role of Humor in the Investigation of Sleep’seffects on Positive Memory” by Alexis Chambers et al. – are being presented in posters at the 19th annual CNS meeting in Chicago.