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Behavioral Science, Neuroscience, Research

Why memories of mistakes may speed up learning

Why memories of mistakes may speed up learning

mistake_learningRemember when you burnt the crab cakes on one side while testing a new recipe for a dinner party and had to compensate by generously dressing them with a creamy sauce? What about the time you were introduced to a friend’s new girlfriend, whose name was somewhat similar to the last one, and you called her the wrong name? Or that accidental trip down a one-way street while in an unfamiliar city? Chances are you didn’t make these mistakes twice.

Now findings (subscription required) published today in Science Express may explain how memories of past errors speed learning of subsequent similar tasks. As explained in a release, scientists have known that when performing a task, the brain records small differences between expectation and reality and uses this information to improve next time. For example, if you’re learning how to drive a car the first time you may press down on the accelerator harder than necessary when shifting from the break pedal. Your brain notes this and next time you press down with a lighter touch. The scientific term for this is “prediction errors,” and the process of learning is largely unconscious. What’s surprising about this latest study is “that not only do such errors train the brain to better perform a specific task, but they also teach it how to learn faster from errors, even when those errors are encountered in a completely different task. In this way, the brain can generalize from one task to another by keeping a memory of the errors.”

To arrive at this conclusion, researchers used a  simple set of experiments where volunteers were placed in front of joystick that was hidden under a screen. More from the release:

Volunteers couldn’t see the joystick, but it was represented on the screen as a blue dot. A target was represented by a red dot, and as volunteers moved the joystick toward it, the blue dot could be programmed to move slightly off-kilter from where they pointed it, creating an error. Participants then adjusted their movement to compensate for the off-kilter movement and, after a few more trials, smoothly guided the joystick to its target. In the study, the movement of the blue dot was rotated to the left or the right by larger or smaller amounts until it was a full 30 degrees off from the joystick’s movement. The research team found that volunteers responded more quickly to smaller errors that pushed them consistently in one direction and less to larger errors and those that went in the opposite direction of other feedback.

Daofen Chen, PhD, a program director at the National Institute of Neurological Disorders and Stroke, commented on the significance of the findings saying, “This study represents a significant step toward understanding how we learn a motor skill … The results may improve movement rehabilitation strategies for the many who have suffered strokes and other neuromotor injuries.”

Previously: Depression, lifestyle choices shown to adversely affect memory across age groups, Newly identified protein helps explain how exercise boosts brain health and Exercise may protect aging brain from memory loss following infection
Photo by Grace

From August 11-25, Scope will be on a limited publishing schedule. During that time, you may also notice a delay in comment moderation. We’ll return to our regular schedule on August 25.

Behavioral Science, Health and Fitness, In the News, Pediatrics, Research

Regular exercise may help young girls struggling with depression

Regular exercise may help young girls struggling with depression

Girls running Scope Blog

Staying physically fit may help keep depression at bay for young girls, a study recently presented at the annual meeting of the American Psychological Association in Washington D.C. showed. On Thursday, the findings were reported in an article in U.S. News & World Report that pointed to a trend between fitness levels and depression in sixth grade girls.

“We don’t know exactly why there is a link [between fitness levels and depression], but it’s probably a number of things,” Camilio Ruggero, PhD, lead researcher and assistant professor at the University of North Texas, said in the article. “It might be better self-esteem, healthier weight or getting more positive reinforcements that go along with being active, and/or it could be more biological. We know certain proteins and hormones associated with less depression respond to increased exercise.”

The article goes on to say that the trend between fitness levels and depression in boys was not as statistically significant. Although the findings could not show a direct link between the two, they do suggest that for middle school children, staying active and being physically fit is an important piece of the puzzle for emotional well-being.

Previously: Using fMRI to understand and potentially prevent depression in girls, Yoga classes may boost high school students’ mental well- being and Lucile Packard Children’s Hospital partners with high schools on student mental health programs
Photo by Sangudo

Behavioral Science, Mental Health, Research

Pump up the bass, not the volume, to feel more powerful

Pump up the bass, not the volume, to feel more powerful

runner_iPodAs any seasoned athlete or fitness fanatic knows, a meticulously curated playlist is key when staying focused before a big game or getting through a tough workout. But what is it about music that transforms our psychological state and make us feel more powerful?

To answer this question, researchers at the Kellogg School of Management at Northwestern University identified so-called “highest power” songs (such as Queen’s “We Will Rock You“) and “lowest power” tunes (such as Fatboy Slim’s “Because We Can“) and then performed a series of experiments designed to ascertain how the music affected individuals’ sense of power, perceived sense of control, competitiveness and abstract thinking. According to a release, their findings showed “that the high-power music not only evoked a sense of power unconsciously, but also systematically generated the three downstream consequences of power.”

Since participants didn’t report increased feelings of empowerment after reading the lyrics of the songs, researchers turned their attention to how manipulation of bass levels impacted listeners. More from the release:

In the bass experiments, the researchers asked participants to listen to novel instrumental music pieces in which bass levels were digitally varied. In one experiment, they surveyed participants about their self-reported feelings of power, and in another, they asked them to perform a word-completion task designed to test implicit, or unconscious, feelings of power. They found that those who listened to the heavy-bass music reported more feelings of power and generated more power-related words in the implicit task than those listening to the low-bass music.

The effects of the bass levels support one possible explanation for why music makes people feel more powerful: the “contagion hypothesis.” The idea is that when people hear specific music components that express a sense of power, they mimic these feelings internally. “Importantly, because we used novel, never-before-heard music pieces in these experiments, it suggests that the effect may sometimes arise purely out of contagion,” [Dennis Hsu, PhD,] says. “Of course, this does not preclude the possibility that music could induce a sense of power through other processes, such as conditioning.”

The “conditioning hypothesis” suggests that certain pieces of music might trigger powerful experiences because these experiences are often paired with that particular music. For example, music used frequently at sports events may elicit powerful feelings because of the association with power, rewards, and winning (e.g., “We Are the Champions” is often played to celebrate victory).

Previously: Why listening to music boosts fitness performance, Can music benefit cancer patients? and Prescription playlists for treating pain and depression?
Photo by Bert Heird

Behavioral Science, Chronic Disease, Neuroscience, Pain, Research, Stanford News

Obscure brain chemical indicted in chronic-pain-induced “Why bother?” syndrome

Obscure brain chemical indicted in chronic-pain-induced "Why bother?" syndrome

why botherChronic pain, meaning pain that persists for months and months or even longer (sometimes continuing well past the time when the pain-causing injury has healed), is among the most abundant of all medical afflictions in the developed world. Estimates of the number of people with this condition in the United States alone range from 70 million to 116 million adults – in other words, as much as half the country’s adult population!

No picnic in and of itself, chronic pain piles insult on injury. It differs from a short-term episode of pain not only in its duration, but also in triggering in sufferers a kind of psychic exhaustion best described by the rhetorical question, “Why bother?”

In a new study in Science, a team led by Stanford neuroscientist Rob Malenka, MD, PhD, has identified a particular nerve-cell circuit in the brain that may explain this loss of motivation that chronic pain all too often induces. Using lab mice as test subjects, they showed that mice enduring unremitting pain lost their willingness to perform work in pursuit of normally desirable goals, just as people in chronic pain frequently do.

It wasn’t that these animals weren’t perfectly capable of carrying out the tasks they’d been trained to do, the researchers showed. Nor was it that they lost their taste for the food pellets which with they were rewarded for successful performance – if you just gave them the food, they ate every bit as much as normal mice did. But they just weren’t willing to work very hard to get it. Their murine morale was shot.

Chalk it up to the action of a mysterious substance used in the brain for god-knows-what. In our release describing the study, I explained:

Galanin is a short signaling-protein snippet secreted by certain cells in various places in the brain. While its presence in the brain has been known for a good 60 years or so, galanin’s role is not well-defined and probably differs widely in different brain structures. There have been hints, though, that galanin activity might play a role in pain. For example, it’s been previously shown in animal models that galanin levels in the brain increase with the persistence of pain.

In a surprising and promising development, the team also found that when they blocked galanin’s action in a particular brain circuit, the mice, while still in as much pain as before, were once again willing to work hard for their supper.

Surprising, because galanin is a mighty obscure brain chemical, and because its role in destroying motivation turns out to be so intimate and specific. Promising, because the discovery suggests that a drug that can inhibit galanin’s activity in just the implicated brain circuit, without messing up whatever this mystery molecule’s more upbeat functions in the brain might be, could someday succeed in bringing back that drive to accomplish things that people in chronic pain all too often lose.

Previously: “Love hormone” may mediate wider range of relationships than previously thought, Revealed: the brain’s molecular mechanism behind why we get the blues, Better than the real thing: How drugs hot-wire our brain’s reward circuitry and Stanford researchers address the complexity of chronic pain
Photo by Doug Waldron

Behavioral Science, Health and Fitness, Mental Health, Research

Exercise and relaxation techniques may help ease social anxiety, study finds

Exercise and relaxation techniques may help ease social anxiety, study finds

TrishWardMeditationPicPhysical exercise and relaxation techniques are common forms of stress-relief. Now, a new study has found that both may help people with social anxiety perceive their surroundings as less threatening environments.

Researchers from Queen’s University in the U.K. conducted two experiments measuring anxiety in participants. In both experiments, the participants were shown point-of-light displays describing a human but not indicating which way the stick figure was facing or whether it appeared to be approaching or receding. Facing-the-viewer bias, a possible biological protective mechanism, may lead people to assume the figure is approaching and posing a threat. And, according to the study, people who are more anxious may place their attention on more threatening stimuli, thereby increasing anxiety.

The researchers tested two means of altering participants’ perception of threat when looking at the stick-figure displays. From a release:

“We wanted to examine whether people would perceive their environment as less threatening after engaging in physical exercise or after doing a relaxation technique that is similar to the breathing exercises in yoga (called progressive muscle relaxation),” researcher [Adam Heenan, a PhD candidate,] said in a statement. “We found that people who either walked or jogged on a treadmill for 10 minutes perceived these ambiguous figures as facing towards them (the observer) less often than those who simply stood on the treadmill. The same was true when people performed progressive muscle relaxation.”

“This is a big development because it helps to explain why exercising and relaxation techniques have been successful in treating and mood and anxiety disorders in the past,” Heenan said.

The research was published in PLOS ONE.

Previously: Research brings meditation’s health benefits into focusAh…OM: Study shows prenatal yoga may relieve anxiety in pregnant womenStudy reveals initial findings on health of most extreme runners and The remarkable impact of yoga breathing for trauma
Photo courtesy of Trish Ward-Torres

Behavioral Science, Medicine and Literature, Stanford News

Does the sight of blood make you queasy? You’re not alone

Does the sight of blood make you queasy? You're not alone

drop of blood2

After writing about my blood phobia — and what I did to tame it — in the spring 2013 issue of Stanford Medicine, I was surprised to get a lot of e-mail from readers suffering from the same condition or similar ones, or both. (In the world of mental health, blood phobia is categorized together with injection phobia and injury phobia, and known collectively as BII phobia.) Their responses gave me a welcome sense of solidarity.

Some sought guidance. A reader in the Philadelphia area wrote:

I now realize I have this phobia. And I had no idea there was a treatment for it.

I pass out with needles, blood and sometimes when someone just talks about blood! Your article actually made me queasy reading it. It took me a while to get through it. But I’m glad I did.

So you know of any treatment centers in Philadelphia who specialize in this?

A reader in the Boston area explained:

From a very young age, I have experienced BII anxiety and vasovagal responses to various medical stimuli.  I used to not be able to talk about injections without feeling uncomfortable or faint, and now I am able to get them without being anxious or needing any medical aides (I used to take Valium).

I am getting closer to my clinical rotations in PA [physician assistant] school and am worried about my irrational fears of blood, surgery, etc.

I was wondering if you had any further suggestions for the student going into health care with these types of BII vasovagal responses.  I am certain I want to be a physician assistant, I am just so concerned that I will not be physically able to carry out my surgical rotations!

Others, like this Bay Area reader,  just wanted to share their experiences:

I first fainted when I was 12 watching a vet surgery! I had no idea what happened or the reaction I had, but I knew it didn’t feel good. I’ve had a few episodes thereafter, usually at doctor’s offices drawing blood. In fact, last year I almost fainted getting my finger pricked at an office health thing! I think the fasting didn’t help… I am so excited to read something like this. To know I’m not the only one, but that there is something you can do, a real exercise to practice that helps!

Thank you for writing this. I truly enjoyed it and feel better already.

Previously: Longreads pick: Blood, sweat and fears
Photo by Alden Chadwick

Behavioral Science, Health and Fitness, Obesity, Research, Stanford News

The behavioral consequences of overindulgence

The behavioral consequences of overindulgence

sundae_070714In today’s world of Big Gulps and supersized portions, one giant question looms: How does overindulgence affect our pleasure of food?

To provide an answer, Baba Shiv, MBA, PhD, a professor at the Stanford Graduate School of Business, and colleagues performed a series of experiments investigating how your feeling of satiety impacts the likelihood that you’ll soon eat the same food again. Their findings offer insights for both individuals that have trouble eating and drinking in moderation and those who are picky eaters.

During the first study, students tried three different flavors of crackers, selected their favorite and then were instructed to eat a specific number. They rated their enjoyment after eating each one. According to a business school release:

The students who ate the larger portion (15 crackers) reported significantly lower enjoyment than those who ate the smaller portion (3 crackers).

These findings replicate previous ones on “sensory-specific satiety”: Each bit of the same food is less pleasant than the one before it. Thus, the bigger the portion, the less enjoyment you get out of the last few bites.

More importantly, participants’ enjoyment of the last cracker (manipulated by portion size) seemed to influence how soon the students wanted to eat the crackers again: Participants who ate a small portion typically opted to receive a giveaway box of [crackers] sooner than did participants who ate the larger portion.

In another study exploring behaviors of finicky eaters, study authors gave one group of participants sips of juice and two crackers to eat. A second group was also given the juice and crackers, but had the added distractor task of counting “e’s” in a series of passages before drinking more juice. Results showed that the crackers partially reset their satiety level, allowing students to find the second sip of juice as enjoyable as the first. Shiv notes in the release how these findings could be useful for parents trying to get their little ones to eat more veggies:

Parents of picky eaters could keep this lesson to heart, says Shiv. Rather than insisting that your child eat every last bite of broccoli, introduce another taste in the middle of the serving of broccoli, to reset levels of satiety. Next time there’s broccoli on the plate, your youngster may be more willing to eat it again.

Continue Reading »

Behavioral Science, Mental Health, Stanford News

Using mindfulness-based programs to reduce stress and promote health

Using mindfulness-based programs to reduce stress and promote health

JamesLeeIn a Stanford BeWell Q&A, Mark Abramson, DDS, the founder and facilitator of Mindfulness-Meditation Based Stress Reduction programs at Stanford Hospital & Clinics and the Stanford School of Medicine, discusses the origins of such practices and how they can be applied in health settings and other areas such as business and education. Abramson leads an eight-week mindfulness meditation course through Stanford’s Health Improvement Program.

From the Q&A:

What is Mindfulness-Based Stress Reduction?

Mindfulness-Based Stress Reduction was originated by Jon Kabat-Zinn, [PhD,] who applied the traditional meditation practice of mindfulness (defined here as non-judgmental awareness) to medical centers. He created an eight-week treatment program for medical illnesses as well as general stress issues. In his program, he used a combination of mindfulness meditation, body awareness, and yoga to assist people with pain and a range of conditions and life issues. MBSR is now a common part of the treatment regimen in many hospital settings.

Meditation looks easy, but can be quite difficult. What is the simplest way to get started?

There are two phenomena that make meditation difficult. The first is the expectation people have that they’re going to go into a mystical, magical place where the mind shuts off and they will be in a special state. This expectation has ruined people’s practice more than anything else. Mindfulness is really just observing yourself through your natural senses — such as your taste, hearing, smelling and feeling. Even the thoughts you have are observable experiences.

The second difficulty is the habitual tendency for our minds to go off on tangents. It is difficult to stay focused; we slip away and we come back. I try to see that as part of the practice.

Previously: Med students awarded Schweitzer Fellowships lead health-care programs for underserved youthA campus-wide call to pause and reflect, Learning tools for mindful eating and Stress, will-power top reasons why Americans fail to adopt healthy habits
Photo of James Lee by Emily Hite

Behavioral Science, Neuroscience, Stanford News

Real time view of changing minds

Real time view of changing minds

There at this morning’s meeting was a large box of donuts which I had absolutely no intention of eating. None. Until I changed my mind.

What happened this morning was probably a little more complex than the simple changes of mind that Stanford Neurosciences Institute director William Newsome studies, what with the delicious smell of chocolate and a quick realization that perhaps a lunchtime run could be squeezed into my day.

Newsome has focused on recording the activity of individual neurons in animals making simple decisions, like indicating which way a dot is moving on a screen. He and his team then statistically analyze the results of many such recordings of individual neurons. These studies have gone a long way toward revealing the activity of neurons in different parts of the brain but can miss some of the fine scale dynamics that take place during the decision-making process. Recently, new probes have been developed that allow scientists to record the activity of many neurons at the same time.

Using such a probe, Newsome and his team recorded groups of neurons in animals making simple decisions, and could track in real time the patterns of how the neurons fired as the animals made a decision and changed their minds. They published their results in Current Biology. A press release from New York University quotes co-first author on the paper Roozbeh Kiani (a former postdoctoral scholar in Newsome’s lab):

“Looking at one neuron at a time is ‘noisy’: results vary from trial to trial so you cannot get a clear picture of this complex activity. By recording multiple neurons at the same time, you can take out this noise and get a more robust picture of the underlying dynamics.”

The team was able to watch the neurons firing in real time, and detect a pattern indicating which decision the animal was going to make. They could also tell when the animal changed its mind, for example as a result of a stronger signal on the screen or to more time to make a decision. What I found interesting is that in most cases when the animals changed their minds it was to correct their initial decision.

What does all this suggest about my donut splurge? Maybe that given enough time I was able to correct my initial decision of self-control to the right one – of deliciousness.

Previously: Co-leader of Obama’s BRAIN Initiative to direct Stanford’s interdisciplinary neuroscience institute

Behavioral Science, Bioengineering, Neuroscience, Research, Stanford News, Technology

Party animal: Scientists nail “social circuit” in rodent brain (and probably ours, too)

Party animal: Scientists nail "social circuit" in rodent brain (and probably ours, too)

party animalStimulating a single nerve-cell circuit among millions in the brain instantly increases a mouse’s appetite for getting to know a strange mouse, while inhibiting it shuts down the same mouse’s drive to socialize with the stranger.

Stanford brain scientist and technology whiz Karl Deisseroth, MD, PhD, is already renowned for his role in developing optogenetics, a technology that allows researchers to turn on and turn off nerve-cell activity deep within the brain of a living, freely roving animal so they can see the effects of that switching in real time. He also pioneered CLARITY, a method of rendering the brain – at least if it’s the size of of a mouse’s – both transparent and porous so its anatomy can be charted, even down to the molecular level, in ways previously deemed unimaginable.

Now, in another feat of methodological derring-do detailed in a new study in Cell, Deisseroth and his teammates incorporated a suite of advanced lab technologies, including optogenetics as well as a couple of new tricks, to pinpoint a particular assembly of nerve cells projecting from one part to another part of the mouse brain. We humans’ brains obviously differ in some ways from those of mice. But our brains have the same connections Deisseroth’s group implicated in mice’s tendency to seek or avoid social contact. So it’s a good bet this applies to us, too.

Yes, we’d all like to be able to flip a switch and turn on our own “party animal” social circuitry from time to time. But the potential long-term applications of advances like this one are far from frivolous. The new findings may throw light on psychiatric disorders marked by impaired social interaction such as autism, social anxiety, schizophrenia and depression.From my release on this study:

“Every behavior presumably arises from a pattern of activity in the brain, and every behavioral malfunction arises from malfunctioning circuitry,” said Deisseroth, who is also co-director of Stanford’s Cracking the Neural Code Program. “The ability, for the first time, to pinpoint a particular nerve-cell projection involved in the social behavior of a living, moving animal will greatly enhance our ability to understand how social behavior operates, and how it can go wrong.”

Previously: Lightning strikes twice: Optogenetics pioneer Karl Deisseroth’s newest technique renders tissues transparent, yet structurally intact, Researchers induce social deficits associated with autism, schizophrenia in mice, Anti-anxiety circuit found in unlikelybrain region and Using light to get muscles moving
Photo by Gamerscore blog

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