Posts tagged cognitive control
Articles and news from the latest research reports.
Reminiscing can help boost mental performance
To solve a mental puzzle, the brain’s executive control network for externally focused, goal-oriented thinking must activate, while the network for internally directed thinking like daydreaming must be turned down to avoid interference – or so we thought.
New research led by Cornell University neuroscientist Nathan Spreng shows for the first time that engaging brain areas linked to so-called “off-task” mental activities (such as mind-wandering and reminiscing) can actually boost performance on some challenging mental tasks. The results advance our understanding of how externally and internally focused neural networks interact to facilitate complex thought, the authors say.
“The prevailing view is that activating brain regions referred to as the default network impairs performance on attention-demanding tasks because this network is associated with behaviors such as mind-wandering,” said Spreng. “Our study is the first to demonstrate the opposite – that engaging the default network can also improve performance.”
There are plenty of neuroimaging studies showing that default network activation interferes with complex mental tasks – but in most, Spreng explained, the mental processes associated with default network conflict with task goals. If you start thinking about what you did last weekend while taking notes during a lecture, for example, your note-taking and ability to keep up will suffer.
Spreng and his team developed a new approach in which off-task processes such as reminiscing can support rather than conflict with the aims of the experimental task. Their novel task, “famous faces n-back,” tests whether accessing long-term memory about famous people, which typically engages default network brain regions, can support short-term memory performance, which typically engages executive control regions.
While undergoing brain scanning, 36 young adults viewed sets of famous and anonymous faces in sequence and were asked to identify whether the current face matched the one presented two faces back. The team found participants were faster and more accurate when matching famous faces than when matching anonymous faces and that this better short-term memory performance was associated with greater activity in the default network. The results show that activity in the default brain regions can support performance on goal-directed tasks when task demands align with processes supported by the default network, the authors say.
“Outside the laboratory, pursuing goals involves processing information filled with personal meaning – knowledge about past experiences, motivations, future plans and social context,” Spreng said. “Our study suggests that the default network and executive control networks dynamically interact to facilitate an ongoing dialogue between the pursuit of external goals and internal meaning.”
ADHD Drug May Help Preserve Our Self-Control Resources
Methylphenidate, also known as Ritalin, may prevent the depletion of self-control, according to research published in Psychological Science, a journal of the Association for Psychological Science.
Self-control can be difficult — sticking with a diet or trying to focus attention on a boring textbook are hard things to do. Considerable research suggests one potential explanation for this difficulty: Exerting self-control for a long period seems to “deplete” our ability to exert self-control effectively on subsequent tasks.
“It is as if self-control is a limited resource that ‘runs out’ if it is used too much,” says lead researcher Chandra Sripada of the University of Michigan. “If we could figure out the brain mechanisms that cause regulatory depletion, then maybe we could find a way to prevent it.”
Previous research has implicated the neurotransmitters dopamine and norepinephrine in regulatory processing. Sripada and University of Michigan collaborators Daniel Kessler and John Jonides decided to see whether manipulating levels of these transmitters might affect regulatory depletion.
The researchers tested 108 adult participants, all of whom took a drug capsule 60 minutes prior to testing. Half of the participants received a capsule that contained methylphenidate, a medication used to treat ADHD that increases brain dopamine and norepinephrine. The other half received a placebo capsule. The study was double-blind, so neither the participants nor the researchers knew at the time of testing who had received which capsule.
The participants then completed a computer-based task in which they were required to press a button when a word containing the letter e appeared on screen. Some were given modified instructions that asked them to refrain from pressing the button if the letter e was next to or one extra letter away from another vowel — this version of the task was designed to tax participants’ self-control.
All of the participants then completed a second computer task aimed at testing their ability to process competing information and exert regulatory control in order to make a correct response.
In line with the researchers’ hypotheses, participants who received the placebo and performed the taxing version of the first task showed greater variability in how quickly they responded in the second task, compared to those whose self-control hadn’t been depleted in the first task.
But for those participants who took the methylphenidate capsule, the first task didn’t have an effect on later performance — the methylphenidate seemed to counteract the self-regulatory depletion incurred by the harder version of the first task.
“These results indicate that depletion of self-control due to prior effort can be fully blocked pharmacologically,” says Sripada. “The task we give people to deplete their self-control is pretty cognitively demanding, so we were surprised at how effective methylphenidate was in blocking depletion of self-control.”
Sripada and colleagues suggest that methylphenidate may help to boost performance of the specific circuits in the brain’s prefrontal cortex that are normally compromised after sustained exertion of self-control.
This doesn’t mean, however, that those of us looking to boost our self-control should go out and get some Ritalin:
“Methylphenidate is a powerful psychotropic medicine that should only be taken with a prescription,” says Sripada. “We want to use this research to better understand the brain mechanisms that lead to depletion of self-control, and what interventions — pharmacological or behavioral — might prevent this.”
Going from Good to Great with Complex Tasks
It is a common belief that consciously thinking about what we are doing interferes with our performance. The origins of this idea go far back. Consider, for instance, the centipede’s dilemma:
A centipede was happy – quite!
Until a toad in fun
Said, “Pray, which leg moves after which?”
This raised her doubts to such a pitch,
She fell exhausted in the ditch
Not knowing how to run.
The centipede performs a very complex task with ease, unless she thinks about the task. The story was thought to illustrate something fundamental about human nature. English psychologist George Humphrey wrote “[the poem] contains a profound truth which is illustrated daily in the lives of all of us.” Humphrey and others thought that not having to think about everything that we do provides a great advantage. According to the famed philosopher Alfred North Whitehead, “Civilization advances by extending the number of important operations which we can perform without thinking about them.” Whitehead believed that thinking must be reserved only for decisive moments.
Though common, this idea is misleading. It is never optimal to run on autopilot. Even the motor tasks that we have learned to do fluently without much cognitive control are better performed while engaged. The key is to realize that we can apply cognitive control at a higher level. Moreover, gaining fluency at a motor task often comes at a cost. The cost is rigidity and deliberately breaking the flow in response to changing contexts often pays off. Musicians, athletes, public speakers, architects, designers, and others whose jobs require complex sequential actions can increase their performance if they understand that they are not trapped in the centipede’s dilemma.
In a fascinating paper, Brain researchers Eitan Globerson and Israel Nelken started with the observation that piano playing involves a very complex sequential motor task. The task is often executed in speeds that do not allow cognitive control of individual muscle movements. Through practice, pianists learn to execute fast and complex motor tasks with little cognitive control. Once this is achieved, it is possible to play in a disengaged way with little cognitive involvement. However, Globerson and Nelken suggest another way. Instead of focusing on individual finger movements or not focusing on anything, pianists may focus on higher-level mental events, such as the character of a longer musical phrase. This allows constant engagement with the music making and deliberate control without disrupting the mechanics of playing. Globerson and Nelken argue that this may dramatically improve performance.
If we follow their argument, it is easy to come up with our own examples about how to use higher-level cognitive control. While playing, a pianist may actively focus on the relationships between different musical ideas. A public speaker may develop a “mental script” that includes bigger-picture ideas, the connections between those ideas, where the climax of the speech should be, and what general effects should the speech make on the audience. During the speech, the public speaker may be constantly engaged with this mental script instead of trying to select words individually or mechanically replicating a previous performance. While shooting, a basketball player may focus on the arc that the ball should follow instead of focusing on arm movements or focusing on nothing. You can create your own examples of higher-level cognitive control for dancing, driving a car, designing a house, or doing the work of a carpenter.
Experts have long been aware of the power of focusing on higher-level mental processes. In 1924, Russian pianist and piano teacher Josef Lhevinne wrote the book Basic Principles in Pianoforte Playing, which later became a classic. In his discussion of memory, he wrote, “the thing to remember is the thought, not the symbols. When you remember a poem you do not remember the alphabetical symbols, but the poet’s beautiful vision, his thought pictures. … Get the thought, the composer’s idea; that is the thing that sticks.”
Higher-level cognitive control is capable of changing the motor action in a beneficial way. When a pianist decides to play a passage in an expressive fashion, for instance, this high-level command changes the character of playing through initiating a sequence of associated motor movements. There is experimental evidence that suggests that performance in highly automatized tasks can be improved by increasing the level of engagement. Musicians in symphony orchestras are typically asked to play the same pieces many times over the course of their careers. The playing of these pieces becomes mostly automatic; and the job satisfaction of orchestra players is typically dismal. Psychologists Ellen Langer, Timothy Russell, and Noah Eisenkraft recently asked a symphony orchestra to record, under different experimental conditions, the finale from Brahms’s Symphony No. 1. A local community chorus listened to and rated the recordings. The musicians were either asked to replicate a previous fine performance or to offer “subtle new nuances” to their performance. Musicians enjoyed the latter performance more; and the majority of the listeners preferred the recording of the latter performance.
There is always an unconscious component of the link between our intentions and the motor actions those intentions create. Even if I deliberately stretch my arm to grab a coffee mug, I do not have conscious control over the way the individual muscles in my arm operate to give rise to the specific stretching movement. Deliberate cognitive control is always less complex than the actual motor action. However, we often learn to apply cognitive control in an even more summary-like way. That is, we can learn to apply cognitive control in a single step over longer and more complex sequences of motor actions. Through practice, sequences of motor actions merge into a single unit that can be initiated by a single deliberate command. This is often called chunking. When children first learn how to brush their teeth or lace their shoes, they deliberately control individual movements that make up the task. After some practice, the individual movements are chunked and the whole sequence can be initiated by a single mental command. Many other daily activities such as riding a bike or writing one’s signature involve chunking. It is possible to merge chunked sequences into even longer sequences and reduce cognitive involvement even more.
Once initiated, a chunked motor sequence is executed automatically. As a consequence, we lose control over individual movements. This type of rigidity is often undesirable because we live in a constantly changing environment. In her book The Power of Mindful Learning Harvard psychologist Ellen Langer talks about how automaticity may get in the way of adapting to new circumstances. Overlearned driving skills may put one in danger while driving in a different country or in different weather conditions. Holding a baseball bat in the same overlearned way after getting older or stronger will hinder performance.
We can disrupt automaticity and appropriately respond to the situation at hand by orienting ourselves in the present and being sensitive to different contexts. We can think at a level higher than the mechanics of the motor action. We can be engaged with the task by making use of these two approaches simultaneously. In any case, thinking should never be reserved.
Reduced cognitive control in passionate lovers
People who are in love are less able to focus and to perform tasks that require attention. Researcher Henk van Steenbergen concludes this, together with colleagues from Leiden University and the University of Maryland. The article has appeared in the journal Motivation and Emotion.
The more in love, the less focused you are
Forty-three participants who had been in a relationship for less than half a year performed a number of tasks during which they had to discriminate irrelevant from relevant information as soon as possible. It appeared that the more in love they were, the less able they were to ignore the irrelevant information. Love intensity thus was related to how well someone is able to focus. There was no difference between men and women.
Cognitive control
The participants listened to music that elicited romantic feelings and thought of a romantic event to intensify their love feelings. Participants also completed a questionnaire that was used to assess the intensity of their love feelings. The results of the study by Henk van Steenbergen differed from results from previous studies. Those previous studies showed that the ability to ignore distracting information is required to maintain a long-term romantic relationship. Being able to control oneself (also called “cognitive control”) and to resist temptations that could threaten the relationship is essential in long-term love.
Thinking of your beloved
In the study by Van Steenbergen, in contrast, the participants had become involved in a romantic relationship only a few months ago. “When you have just become involved in a romantic relationship you’ll probably find it harder to focus on other things because you spend a large part of your cognitive resources on thinking of your beloved”, Van Steenbergen says. “For long-lasting love in a long-term relationship, on the other hand, it seems crucial to have proper cognitive control.” Over time, a balance between less and more cognitive control may be critical for a successful relationship.
Why is romantic love associated with cognitive control?
Van Steenbergen emphasizes that the link between romantic love and cognitive control is a new area of research. “The reason why romantic love is associated with cognitive control is still unknown. It could be that lovers use all their cognitive resources to think about their beloved, which leaves them no resources to perform a boring task. It could also be that the association goes in the opposite direction: people who have reduced cognitive control may experience more intense love feelings than people who have higher levels of cognitive control.” Future research will have to clarify this.
(Source: news.leiden.edu)
Training the Older Brain in 3-D: Video Game Enhances Cognitive Control
Scientists at UC San Francisco are reporting that they have found a way to reverse some of the negative effects of aging on the brain, using a video game designed to improve cognitive control.
The findings, published on Sept. 5 in Nature, show that a specially designed 3-D video game can improve cognitive performance in healthy older adults, they said. The researchers said the study provides a measure of scientific support to the burgeoning field of brain fitness, which has been criticized for lacking evidence that such training can induce lasting and meaningful changes.
In the game, which was developed by the UCSF researchers, participants race a car around a winding track while a variety of road signs pop up. Drivers are instructed to keep an eye out for a specific type of sign, while ignoring all the rest, and to press a button whenever that particular sign appears. The need to switch rapidly from driving to responding to the signs – i.e. multitasking – generates interference in the brain that undermines performance. The researchers found that this interference increases dramatically across the adult lifespan.
But after receiving just 12 hours of training on the game, spread over a month, the 60- to 85-year-old study participants improved their performance until it surpassed that of 20-somethings who played the game for the first time.
The training also improved the participants’ performance in two other important cognitive areas: working memory and sustained attention. And participants maintained their skills at the video game six months after the training had ended.
“The finding is a powerful example of how plastic the older brain is,” said Adam Gazzaley, MD, PhD, UCSF associate professor of neurology, physiology and psychiatry and director of the Neuroscience Imaging Center. Gazzaley co-founded the company, Akili Interactive Labs, which is developing the next generation of the video game.
Gazzaley, who has made a career out of studying how distraction affects cognitive performance, said his game, NeuroRacer, does more than any ordinary game – be it bridge, a crossword puzzle, or an off-the-shelf video game – to condition the brain. Like a good teacher, he said, NeuroRacer undermines people’s natural tendency to go on automatic pilot once they’ve mastered a skill, and pushes them further than they think they can go.
“Normally, when you get better at something, it gets easier,” he said. But with this game, “when you get better, it gets harder.”
Brain Training Reverses Age-Related Decline
Evidence that the adult brain is capable of learning has been accumulating for more than a dozen years. A study of London taxi drivers, for example, found that their brains had changed as they learned to navigate the city’s notoriously complicated streets. Nevertheless, Gazzaley said the brain’s function often erodes steadily over time in many areas, with some exceptions, like wisdom.
Given this, Gazzaley said it’s encouraging that even a small amount of brain training can reverse some of the age-related decline.
Gazzaley’s group found evidence of a possible brain mechanism that may explain the improvements he saw in his older subjects, and why these gains transferred to other cognitive areas. Electroencephalograph (EEG) recordings point to changes in a neural network involved in cognitive control, which is necessary to pursue goals.
The scientists measured midline frontal theta – or low frequency oscillations – in the prefrontal cortex, as well as the coherence in these waves between frontal and posterior regions of the brain. As the older “drivers” became more adept at the multitasking challenges of NeuroRacer, their brains modulated this key neural network and its activity began to resemble that of young adults.
Both of these measures – midline frontal theta and theta coherence – are well established neural markers of cognitive control that have been associated with many of the processes that enable people to pursue their goals.
We see this as evidence that the training may have improved our study participants’ ability to stay in an engaged, active state for a longer period of time,” said Joaquin A. Anguera, the paper’s first author and a post-doctoral fellow in Gazzaley’s lab.
Indeed, the researchers found that the training-induced changes in this neural network predicted how well participants would do on a different test, called the Test of Variables of Attention (TOVA), which measures sustained attention.
“The amount that midline frontal theta went up was related to something that was untrained, this other measure, the TOVA,” Anguera said. “It implies there’s something that changed that was common to the training and to the task we tested afterwards.”
Gazzaley said these findings point toward a common neural basis of cognitive control that is enhanced by the challenging and high-interference conditions of the video game, and this might explain how racing a car in 3-D could improve something as seemingly unrelated as memory.
If the finding holds, it could have wide application. Other brain disorders like ADHD, depression and dementia are also associated with deficits in cognitive control.
“Follow up studies using functional Magnetic Resonance Imaging and transcranial electrical stimulation are still needed to better understand exactly how this network is involved in the performance changes,” Gazzaley said.
Brainwaves reflect ability to beat built-in bias
Many animals, including humans, harbor ingrained biases to act when they can obtain rewards and to remain inactive to avoid punishment. Sometimes, however those biases can steer us wrong. A new study finds that theta brainwave activity in the prefrontal cortex predicts how well people can overcome these biases when a better choice are available.
Vertebrates are predisposed to act to gain rewards and to lie low to avoid punishment. Try to teach chickens to back away from food in order to obtain it, and you’ll fail, as researchers did in 1986. But humans are better thinkers than chickens. In the May 8 edition of the Journal of Neuroscience, researchers show that the level of theta brainwave activity in the prefrontal cortex predicts whether people will be able to overcome these ingrained biases when doing so is required to achieve a goal.
The study helps explain a distinctly human mechanism of cognition, said the lead researchers at Brown University, and could be applied to studying and treating reward-seeking or punishment-avoidance conditions such as addiction or obsessive-compulsive disorder.
Despite how we have evolved, life doesn’t always encourage acting to gain reward or freezing to avoid punishment. Sometimes we must restrain ourselves to gain a reward (baseball batters can get on base by not swinging at bad pitches) or take action to avoid a penalty (tax cheaters can come forward during amnesties). Acting counter to our ingrained Pavlovian biases is a matter of the brain recognizing the conflict between the rational course of action and the instinct.
“We have suggested that more advanced brain mechanisms in the prefrontal are needed to exert cognitive control over behavior in these circumstances,” said Michael Frank, associate professor of cognitive, linguistic and psychological sciences and the paper’s senior author. “This study provides evidence that temporally specific brain activity within the prefrontal cortex is related to this ability, both between and within individuals.”
Human vs. bias
That brain activity could be measured and quantified as theta brainwaves. Brown postdoctoral researcher James Cavanagh led the research in which he recruited 34 people to play a custom-designed computer game while wearing EEG scalp monitors.
The game involved four scenarios, all reinforced by putting a little real money on the line: the instinctual scenarios of clicking for a reward and not clicking to avoid a penalty, and the trickier scenarios of clicking to avoid penalty and not clicking to gain a reward.
Over many rounds, players tried to learn what to do when presented with one of four distinct symbols, each of which corresponded to a different scenario.
Cavanagh programmed the scenarios usually, but not always, to reward the proper behavior. For this reason, people had to pay attention to what was likely, rather than merely memorize a simple reliable pattern.
Cavanagh and his co-authors measured how well people learned the proper action for each scenario. With the advantage of instinct, almost everyone learned to click for a reward. Most people also managed to learn not to click to avoid penalty and even managed in similar numbers to click to avoid penalty. Like the chickens, however, significantly fewer people could restrain themselves in order to gain a reward.
Those who were bad at overcoming one Pavlovian bias were much more likely to fail at the other.
While the subjects were playing the game, the experimenters also measured theta brainwave activity in each subject’s prefrontal cortex — for instance at the exact moment they saw the distinct symbols of the tasks.
The main idea of the study was to correlate the subjects’ theta brain activity during the tasks with their ability to overcome ingrained bias when appropriate. Sure enough, the subject’s ability to repress Pavlovian bias was predicted by the enhancement of theta during the trials when the bias was unwanted, compared to when it provided proper guidance.
“Some people are really good at it and some are not, and we were able to predict that from their brain activity,” Cavanagh said.
This was not only true when comparing individual subjects, but also when comparing the subjects to themselves at different times (e.g., some subjects’ abilities wavered from task to task and the theta varied right along).
Many psychological factors could have confounded the results — differential sensitivity to gains and losses, for example – but Cavanagh and Frank controlled for those with the help of a sophisticated computer model that accounts for and statistically disentangles the relationship of bias and theta from those other influences.
Our better nature
All of the study subjects were screened to ensure they were psychiatrically healthy. In these subjects, the study results not only confirmed that people harbor the ingrained biases, but that they differ in their ability to overcome them. Frank said the variations likely come from innate and situational factors. Evidence suggests that the degree of ingrained bias may have genetic and neurological roots, he said, but can also vary within the same individual based on factors such as fatigue or stress.
For people with psychiatric disorders, Cavanagh said, the predictive value of measurable theta activity for behavioral patterns could become an important tool for diagnosis and predicting treatment outcomes.
Frank, who is affiliated with the Brown Institute for Brain Science, added that the lab has begun studying whether people can improve behavior by purposely modulating theta activity. If so, that could lead to a therapy for addiction.
“We are beginning studies that allow us to safely manipulate activity in specific frequencies like theta in the frontal cortex which will allow us to assess the causal role these signals may be playing,” he said.
It’s not easy to work against primal intuition, but people have that ability and now researchers know how that ability is reflected in brains.
“This tells us a lot about the neurobiology of why we’re special,” Cavanagh said.
Researchers Show that Suppressing the Brain’s “Filter” Can Improve Performance in Creative Tasks
The brain’s prefrontal cortex is thought to be the seat of cognitive control, working as a kind of filter that keeps irrelevant thoughts, perceptions and memories from interfering with a task at hand.
Now, researchers at the University of Pennsylvania have shown that inhibiting this filter can boost performance for tasks in which unfiltered, creative thoughts present an advantage.
The research was conducted by Sharon Thompson-Schill, the Christopher H. Browne Distinguished Professor of Psychology and director of the Center for Cognitive Neuroscience, and Evangelia Chrysikou, a member of her lab who is now an assistant professor at the University of Kansas. They collaborated with Roy Hamilton and H. Branch Coslett of the Department of Neurology at Penn’s Perelman School of Medicine and Abhishek Datta and Marom Bikson of the Department of Biomedical Engineering at the City College of New York.
Their work was published in the journal Cognitive Neuroscience.