Neuroscience
Month
Procrastination and impulsivity are genetically linked, suggesting that the two traits stem from similar evolutionary origins, according to research published in Psychological Science, a journal of the Association for Psychological Science. The research indicates that the traits are related to our ability to successfully pursue and juggle goals.
“Everyone procrastinates at least sometimes, but we wanted to explore why some people procrastinate more than others and why procrastinators seem more likely to make rash actions and act without thinking,” explains psychological scientist and study author Daniel Gustavson of the University of Colorado Boulder. “Answering why that’s the case would give us some interesting insights into what procrastination is, why it occurs, and how to minimize it.”
From an evolutionary standpoint, impulsivity makes sense: Our ancestors should have been inclined to seek immediate rewards when the next day was uncertain.
Procrastination, on the other hand, may have emerged more recently in human history. In the modern world, we have many distinct goals far in the future that we need to prepare for – when we’re impulsive and easily distracted from those long-term goals, we often procrastinate.
Thinking about the two traits in that context, it seems logical that people who are perpetual procrastinators would also be highly impulsive. Many studies have observed this positive relationship, but it is unclear what cognitive, biological, and environmental influences are responsible for it.
The most effective way to understand why these traits are correlated is to study human twins. Identical twins — who share 100% of their genes — tend to show greater similarities in behavior than fraternal twins, who only share 50% of their genes (just like any other siblings). Researchers take advantage of this genetic discrepancy to figure out the relative importance of genetic and environmental influences on particular behaviors, like procrastination and impulsivity.
Gustavson and colleagues had 181 identical-twin pairs and 166 fraternal-twin pairs complete several surveys intended to probe their tendencies toward impulsivity and procrastination, as well as their ability to set and maintain goals.
They found that procrastination is indeed heritable, just like impulsivity. Not only that, there seems to be a complete genetic overlap between procrastination and impulsivity — that is, there are no genetic influences that are unique to either trait alone.
That finding suggests that, genetically speaking, procrastination is an evolutionary byproduct of impulsivity — one that likely manifests itself more in the modern world than in the world of our ancestors.
In addition, the link between procrastination and impulsivity also overlapped genetically with the ability to manage goals, lending support to the idea that delaying, making rash decisions, and failing to achieve goals all stem from a shared genetic foundation.
Gustavson and colleagues are now investigating how procrastination and impulsivity are related to higher-level cognitive abilities, such as executive functions, and whether these same genetic influences are related to other aspects of self-regulation in our day-to-day lives.
“Learning more about the underpinnings of procrastination may help develop interventions to prevent it, and help us overcome our ingrained tendencies to get distracted and lose track of work,” Gustavson concludes.
Whether at the office, dorm, PTA meeting, or any other social setting, we all know intuitively who the popular people are – who is most liked – even if we can’t always put our finger on why. That information is often critical to professional or social success as you navigate your social networks. Yet until now, scientists have not understood how our brains recognize these popular people. In new work, researchers say that we track people’s popularity largely through the brain region involved in anticipating rewards.
“Being able to track other people’s status in your group is incredibly important in survival terms,” says Kevin Ochsner of Columbia University. “Knowing who is popular or likeable is critically important in times of need or distress, when you seek an alliance, or need help – whether physical or political – etc.” While sociologists, psychologists, and anthropologists have long studied these group dynamics, neuroscientists have only begun to scratch the surface of how we think about people’s social status.
That is all changing, though, Ochsner says with many areas of work bringing together social psychology and sociology with cognitive neuroscience to better understand how individual brain processes connect to group membership. As will be presented today at the annual meeting of the Cognitive Neuroscience Society (CNS) in Boston, researchers are now studying at the neural level everything from social popularity to how ideas successfully spread in groups.
Improved thinking. Decreased appetite. Lowered blood pressure. The potential health benefits of dark chocolate keep piling up, and scientists are now homing in on what ingredients in chocolate might help prevent obesity, as well as type-2 diabetes. They found that one particular type of antioxidant in cocoa prevented laboratory mice from gaining excess weight and lowered their blood sugar levels. The report appears in ACS’ Journal of Agricultural & Food Chemistry.
Andrew P. Neilson and colleagues explain that cocoa, the basic ingredient of chocolate, is one of the most flavanol-rich foods around. That’s good for chocolate lovers because previous research has shown that flavanols in other foods such as grapes and tea can help fight weight gain and type-2 diabetes. But not all flavanols, which are a type of antioxidant, are created equal. Cocoa has several different kinds of these compounds, so Neilson’s team decided to tease them apart and test each individually for health benefits.
The scientists fed groups of mice different diets, including high-fat and low-fat diets, and high-fat diets supplemented with different kinds of flavanols. They found that adding one particular set of these compounds, known as oligomeric procyanidins (PCs), to the food made the biggest difference in keeping the mice’s weight down if they were on high-fat diets. They also improved glucose tolerance, which could potentially help prevent type-2 diabetes. “Oligomeric PCs appear to possess the greatest antiobesity and antidiabetic bioactivities of the flavanols in cocoa, particularly at the low doses employed for the present study,” the researchers state.
Cigarette smoking among obese women appears to interfere with their ability to taste fats and sweets, a new study shows. Despite craving high-fat, sugary foods, these women were less likely than others to perceive these tastes, which may drive them to consume more calories.
M. Yanina Pepino, PhD, assistant professor of medicine at Washington University School of Medicine in St. Louis, and Julie Mennella, PhD, a biopsychologist at the Monell Center in Philadelphia, where the research was conducted, studied four groups of women ages 21 to 41: obese smokers, obese nonsmokers, smokers of normal weight and nonsmokers of normal weight. The women tasted several vanilla puddings containing varying amounts of fat and were asked to rate them for sweetness and creaminess, a measure of fat content.
“Compared with the other three groups, smokers who were obese perceived less creaminess and sweetness,” Pepino said. “They also derived less pleasure from tasting the puddings.”
The findings are published in the April issue of the journal Obesity.
Pepino cautioned that the study only identified associations between smoking and taste rather than definitive reasons why obese smokers were less likely to detect fat and sweetness. But the findings imply that the ability to perceive fat and sweetness — and to derive pleasure from food — is compromised in female smokers who are obese, which could contribute to the consumption of more calories.
“Obese people often crave high-fat foods,” she said. “Our findings suggest that having this intense craving but not perceiving fat and sweetness in food may lead these women to eat more. Since smoking and obesity are risk factors for cardiovascular and metabolic diseases, the additional burden of craving more fats and sugars, while not fully tasting them, could be detrimental to health.”
Interestingly, it was the combination of smoking and obesity that created something of a “double-whammy” because smokers who were not overweight could perceive fat and sweetness that was similar to women who did not smoke.
Previous studies have linked smoking to increased food cravings and greater consumption of fat, regardless of whether a smoker is obese. Studies also have found that smokers tend to have increased waist-to-hip ratios. That is, they tend to be shaped more like apples than pears, another risk factor for heart disease and metabolic problems.
The findings contribute to a growing body of knowledge that challenges the lingering perception that smoking helps a person maintain a healthy weight.
“Women are much more likely than men to take up smoking as an aid to weight control,” Pepino said. “But there is no good evidence showing that it helps maintain a healthy weight over the long term. And in the case of obese women who smoke, it appears the smoking may make things even worse than previously thought.”
According to a new study by researchers at Ben-Gurion University of the Negev (BGU) and the University of Amsterdam, oxytocin caused participants to lie more to benefit their groups, and to do so more quickly and without expectation of reciprocal dishonesty from their group. Oxytocin is a hormone the body naturally produces to stimulate bonding.
The research was published this week in the Proceedings of the National Academy of Science (PNAS).
"Our results suggest people are willing to bend ethical rules to help the people close to us, like our team or family," says Dr. Shaul Shalvi of Ben-Gurion University of the Negev’s Department of Psychology and director of BGU’s Center for Decision Making and Economic Psychology. "This raises an interesting, although perhaps more philosophical, question: Are all lies immoral?"
Dr. Shalvi’s research focuses on ethical decision-making and the justifications people use to do wrong and still feel moral. Specifically, he looks at what determines how much people lie and which settings increase people’s honesty. Very little is known about the biological foundations of immoral behavior.
"Together, these findings fit a functional perspective on morality revealing dishonesty to be plastic and rooted in evolved neurobiological circuitries, and align with work showing that oxytocin shifts the decision-maker’s focus from self to group interests," Shalvi says.
"The results highlight the role of bonding and cooperation in shaping dishonesty, providing insight into when and why collaboration turns into corruption."
Oxytocin is a peptide of nine amino acids produced in the brain’s hypothalamus, functioning as both a hormone and neurotransmitter. Research has shown that in addition to its bonding effect in couples and between mothers and babies, it also stimulates one’s social approach.
Higher levels of oxytocin correlate with greater empathy, lower social anxiety and more pro-social choice in anonymous games; reduction in fear response; and greater trust in interpersonal exchange. It also stimulates defense-related aggression.
In the experiment designed by Shalvi and fellow researcher Carsten K. W. De Dreu of the University of Amsterdam’s Department of Psychology, 60 male participants received an intranasal dose of either oxytocin or placebo. They were then split into teams of three and asked to predict the results of 10 coin tosses.
Participants were asked to toss the coin, see the outcome and report whether their prediction was correct. They knew that for each correct prediction, they could lie and earn more money to split between their group members, who were engaging in the same task.
"The statistical probability of someone correctly guessing the results of nine or 10 coin tosses is about one percent," says Shalvi. "Yet, 53 percent of those who were given oxytocin claimed to have correctly predicted that many coin tosses, which is extremely unlikely."
Only 23 percent of the participants who received the placebo reported the same results, reflecting a high likelihood that they were also lying, but to a lesser extent compared to those receiving oxytocin.
The first UK study of the use of ketamine intravenous infusions in people with treatment-resistant depression has been carried out in an NHS clinic by researchers at Oxford Health NHS Foundation Trust and the University of Oxford.
'Ketamine is a promising new antidepressant which works in a different way to existing antidepressants. We wanted to see whether it would be safe if given repeatedly, and whether it would be practical in an NHS setting. We especially wanted to check that repeated infusions didn't cause cognitive problems,' explains principal investigator Dr Rupert McShane, a consultant psychiatrist at Oxford Health and a researcher in Oxford University's Department of Psychiatry.
The researchers confirmed that ketamine has a rapid antidepressant effect in some patients with severe depression who have not responded to other treatments. These are patients suffering from severe depression which may have lasted years despite multiple antidepressants and talking therapies. Although many patients relapsed within a day or two, 29% had benefit which lasted at least three weeks and 15% took over two months to relapse.
Ketamine did not cause cognitive or bladder side effects when given on up to six occasions, although some people did experience other side effects such as anxiety during the infusion or being sick. The team have now given over 400 infusions to 45 patients and are exploring ways to maintain the effect. They report their findings in the Journal of Psychopharmacology. The study was funded by National Institute for Health Research (NIHR) Research for Patient Benefit Programme.
Relapse is the most painful and expensive feature of drug addiction—even after addicted individuals have been drug-free for months or years, the likelihood of sliding back into the habit remains high. The National Institute on Drug Abuse estimates that 40 to 60 percent of addicted individuals will relapse, and in some studies the rates are as high as 80 percent at six months after treatment. Though some relapse triggers can be consciously avoided, such as people, places and things related to drug use, other subconscious triggers related to the brain’s reward system may be impossible to avoid— they can gain entry to the unconscious brain, setting the stage for relapse.
Researchers at Penn Medicine’s Center for Studies of Addiction have now found that the drug baclofen, commonly used to prevent spasms in patients with spinal cord injuries and neurological disorders, can help block the impact of the brain’s response to “unconscious” drug triggers well before conscious craving occurs. They suggest that this mechanism has the potential to prevent cocaine relapse. The new findings are reported in the Journal of Neuroscience.
Researchers from the Allen Institute for Brain Science have published the first comprehensive, large-scale data set on how the brain of a mammal is wired, providing a groundbreaking data resource and fresh insights into how the nervous system processes information. Their landmark paper in this week’s issue of the journal Nature both describes the publicly available Allen Mouse Brain Connectivity Atlas, and demonstrates the exciting knowledge that can be gleaned from this valuable resource.
(Image: Connectivity Dot-o-Gram)
“Understanding how the brain is wired is among the most crucial steps to understanding how the brain encodes information,” explains Hongkui Zeng, Senior Director of Research Science at the Allen Institute for Brain Science. “The Allen Mouse Brain Connectivity Atlas is a standardized, quantitative, and comprehensive resource that will stimulate exciting investigations around the entire neuroscience community, and from which we have already gleaned unprecedented details into how structures are connected inside the brain.”
Using the data, Allen Institute scientists were able to demonstrate that there are highly specific patterns in the connections among different brain regions, and that the strengths of these connections vary with greater than five orders of magnitudes, balancing a small number of strong connections with a large number of weak connections. This publication comes just as the research team wraps up more than four years of work to collect and make publicly available the data behind the Allen Mouse Brain Connectivity Atlas project, with the completion of the Atlas announced in March 2014.
First major report using data from the BrainSpan Atlas of the Developing Human Brain shines a light on where genes are turned on in the brain during mid-pregnancy, what goes wrong in developmental disorders like autism, and what makes human brains unique.
Researchers at the Allen Institute for Brain Science have generated a high-resolution blueprint for how to build a human brain, with a detailed map of where different genes are turned on and off during mid-pregnancy at unprecedented anatomical resolution. This first major report using data from the BrainSpan Atlas of the Developing Human Brain is published in the journal Nature this week. The data provide exceptional insight into diseases like autism that are linked to early brain development, and to the origins of human uniqueness. The rich data set is publicly available to everyone via the Allen Brain Atlas data portal.
“Knowing where a gene is expressed in the brain can provide powerful clues about what its role is,” says Ed Lein, Investigator at the Allen Institute for Brain Science. “This atlas gives a comprehensive view of which genes are on and off in which specific nuclei and cell types while the brain is developing during pregnancy. This means that we have a blueprint for human development: an understanding of the crucial pieces necessary for the brain to form in a normal, healthy way, and a powerful way to investigate what goes wrong in disease.”
This paper represents the first major report to make use of data collected for the BrainSpan Atlas of the Developing Human Brain, a big science consortium initiative which seeks to create a map of the transcriptome across the entire course of human development. “Coming on the first anniversary of the BRAIN Initiative, this is a terrific example of the potential for public-private partnerships to accelerate progress in neuroscience,” says Lein.
Thomas R. Insel, Director of the National Institute of Mental Health, praises the BrainSpan Atlas as an already invaluable tool to researchers. “While we have had previous reports of molecular and cellular changes during human brain growth, the BrainSpan Atlas is the first comprehensive map of the dramatic trajectory of gene expression across prenatal and postnatal development,” he says. “This atlas is already transforming the way scientists approach human brain development and neurodevelopmental disorders like autism and schizophrenia. Although the many genes associated with autism and schizophrenia don’t show a clear relationship to each other in the adult brain, the BrainSpan Atlas reveals how these diverse genes are connected in the prenatal brain.”
A new University of Illinois study finds that obese children are slower than healthy-weight children to recognize when they have made an error and correct it. The research is the first to show that weight status not only affects how quickly children react to stimuli but also impacts the level of activity that occurs in the cerebral cortex during action monitoring.
“I like to explain action monitoring this way: when you’re typing, you don’t have to be looking at your keyboard or your screen to realize that you’ve made a keystroke error. That’s because action monitoring is occurring in your brain’s prefrontal cortex,” said Charles Hillman, a U of I professor of kinesiology and faculty member in the U of I’s Division of Nutritional Sciences.
As an executive control task that requires organizing, planning, and inhibiting, action monitoring requires people to be computational and conscious at all times as they process their behavior. Because these higher-order cognitive processes are needed for success in mathematics and reading, they are linked with success in school and positive life outcomes, he said.
“Imagine a child in a math class constantly checking to make sure she’s carrying the digit over when she’s adding. That’s an example,” he added.
In the study, the scientists measured the behavioral and neuroelectric responses of 74 preadolescent children, half of them obese, half at a healthy weight. Children were fitted with caps that recorded electroencephalographic activity and asked to participate in a task that presented left- or right-facing fish, predictably facing in either the same or the opposite direction. Children were asked to press a button based on the direction of the middle (that is, target) fish. The flanking fish either pointed in the same direction (facilitating) or in the opposite direction (hindering) their ability to respond successfully.
“We found that obese children were considerably slower to respond to stimuli when they were involved in this activity,” Hillman said.
The researchers also found that healthy-weight children were better at evaluating their need to change their behavior in order to avoid future errors.
“The healthy-weight kids were more accurate following an error than the obese children were, and when the task required greater amounts of executive control, the difference was even greater,” he reported.
A second evaluation measured electrical activity in the brain “that occurs at the intersection of thought and action,” Hillman said. “We can measure what we call error-related negativity (ERN) in the electrical pattern that the brain generates following errors. When children made an error, we could see a larger negative response. And we found that healthy-weight children are better able to upregulate the neuroelectric processes that underlie error evaluation.”
Scientists in the Hillman lab and elsewhere have seen a connection between healthy weight and academic achievement, “but a study like this helps us understand what’s happening. There are certainly physiological differences in the brain activity of obese and healthy-weight children. It’s exciting to be able to use functional brain imaging to see the way children’s weight affects the aspects of cognition that influence and underlie achievement,” said postdoctoral researcher and co-author Naiman Khan.