In The News
New research with rats suggests that for the 15 million Americans who don’t have the typical nine-to-five workday, working the graveyard shift or rotating shifts may have serious implications for the brain.
“The body is synchronized to night and day by circadian rhythms — 24-hour cycles controlled by internal biological clocks that tell our bodies when to sleep, when to eat and when to perform numerous physiological processes,” said David Earnest, Ph.D., a professor in the Department of Neuroscience and Experimental Therapeutics at the Texas A&M Health Science Center College of Medicine.
“A person on a shift work schedule, especially on rotating shifts, challenges, or confuses, their internal body clocks by having irregular sleep-wake patterns or meal times.”
According to Earnest, it’s not the longer hours — or the weird hours — that is the problem. Instead, it is the change in the timing of waking, sleeping, and eating every few days that “unwinds” our body clocks and makes it difficult for them to maintain their natural, 24-hour cycle.
When body clocks are disrupted, as they are when people go to bed and get up at radically different times every few days, there can be a major impact on health. Earnest and his colleagues have found that shift work can lead to more severe ischemic strokes, the leading cause of disability in the United States, which occur when blood flow is cut off to part of the brain.
Earnest and his team, including colleague Farida Sohrabji, Ph.D., also a professor in the Department of Neuroscience and Experimental Therapeutics and director of the Women’s Health in Neuroscience Program, found that subjects on shift work schedules had more severe stroke outcomes. Those outcomes included both more severe brain damage and loss of sensation and limb movement than those in a control group on regular 24-hour cycles of day and night.
Supported by the American Heart Association, the study also found that males and females show major differences in the degree to which the stroke was exacerbated by circadian rhythm disruption. In males, the gravity of stroke outcomes in response to shift work schedules was much worse than in females, according to the study’s findings.
“These sex differences might be related to reproductive hormones,” Sohrabji said. “Young women are less likely to suffer strokes, as compared with men of a similar age, and when they do, the stroke outcomes are likely to be less severe.”
In females, estrogen is thought to be responsible for this greater degree of neuroprotection, she noted.
“Essentially, estrogen helps shield the brain in response to stroke,” she explained.
However, older women approaching menopause show increasing incidence of ischemic stroke and poor prognosis for recovery, compared with men at the same age.
Earnest’s earlier work showed that a high-fat diet can also alter the timing of internal body clocks, as well as dramatically increase inflammatory responses that can be a problem in cardio- and cerebrovascular disease. These conditions are caused by problems that affect the blood supply to the brain, which includes stroke.
“Next we would like to explore whether inflammation is a key link between circadian rhythm disruption and increased stroke severity,” Earnest said.
“With this information, we may be able to identify therapeutic interventions that limit damage after a stroke in patients with a history of shift work.”
“This research has clear implications for shift workers with odd schedules, but probably extends to many of us who keep schedules that differ greatly from day-to-day, especially from weekdays to weekends,” Earnest continued.
“These irregular schedules can produce what is known as ‘social jet lag,’ which similarly unwinds our body clocks so they no longer keep accurate time, and thus can lead to the same effects on human health as shift work.”
He adds that people who are in professions where they are on different shifts should be monitored more closely and more frequently for cardio- and cerebrovascular disease and risk factors such as hypertension and obesity.
In the meantime, Earnest suggests that those with irregular sleeping patterns should at least try to maintain regular mealtimes, in addition to avoiding the usual cardiovascular risk factors, such as a high-fat diet, inactivity and smoking.
The study is accepted for publication in the journal Endocrinology.
New research shows that for women with a history of migraines, estrogen levels may drop more rapidly in the days just before menstruation than for women who don’t suffer from migraines.
The study also showed that women with a history of migraines had a faster rate of estrogen decline regardless of whether they had a migraine during that particular menstrual cycle.
“These results suggest that a ‘two-hit’ process may link estrogen withdrawal to menstrual migraine. More rapid estrogen decline may make women vulnerable to common triggers for migraine attacks such as stress, lack of sleep, foods, and wine,” said study author Jelena Pavlovic, M.D., Ph.D., of Albert Einstein College of Medicine/Montefiore Medical Center in Bronx, N.Y., and a member of the American Academy of Neurology.
For the study, researchers reviewed migraine history, daily headache diaries, and hormone data for 114 women with a history of migraine and 223 women without a history of migraine. The average age of the women was 47 years old.
The researchers measured hormone levels from daily urine samples for one monthly cycle. The women’s peak hormone levels, average daily levels, and day-to-day rates of decline were calculated over the five days following each hormone peak in their cycles.
In the two days after the peak estrogen level in the luteal phase of the cycle, which is the time after ovulation and before menstruation, the estrogen levels in the women with migraine dropped by 40 percent compared to 30 percent for women without migraine, according to the study’s findings.
The rate dropped 34 picrograms per milligram of creatinine (pg/mgCr) in women with migraine, compared to 23 pg/mgCr in women without migraine.
“Future studies should focus on the relationship between headaches and daily hormone changes and explore the possible underpinnings of these results,” said Pavlovic.
While the study’s size and amount of hormone data are strengths, limitations include proportionately more Chinese and Japanese women in the group of women without migraine and more white and black women in the migraine group. The level of sex hormones may differ according to racial and ethnic differences, the researchers noted.
The study is published in Neurology, the medical journal of the American Academy of Neurology.
Source: American Academy of Neurology
An online study of male college students suggests that sexual coercion by college athletes is far more widespread than previously believed, even given the numerous recent scandals involving sexual assault.
The study, published in the journal Violence Against Women, found that more than half of those who play on intercollegiate and recreational sports teams reported engaging in sexual coercion, including rape.
In an online survey about sexual activity and attitudes, more than half the men who played an intramural or intercollegiate sport reported coercing a partner into sex.
The increased risk of sexual coercion by athletes was linked to “traditional” beliefs about women and a higher belief in rape “myths,” which are used to justify sexual assault, according to researchers at North Carolina State University.
The study also found that more than a third of non-athletes reported engaging in sexual coercion, including rape.
Previous research has shown that male college athletes are more likely than college students in general to commit sexual violence or engage in sexual coercion. In 2011, the U.S. Department of Education called for colleges and universities to institute efforts to educate athletes and address sexual violence.
“We wanted to know what these programs need to address,” said Dr. Sarah Desmarais, an associate professor of psychology at North Carolina State University and co-author of the recent study.
“What are the factors that contribute to these higher rates of sexual assault? And are these issues confined to intercollegiate athletes, or do they extend to club and intramural athletes?”
For the study, researchers surveyed 379 male undergraduates online, including 191 non-athletes, 29 intercollegiate athletes, and 159 recreational athletes.
The men were asked about their sexual behavior, their attitudes toward women and the degree to which they believed in rape myths.
“We found that 54.3 percent of the intercollegiate and recreational athletes and 37.9 percent of non-athletes had engaged in sexually coercive behaviors, almost all of which met the legal definition of rape,” said Desmarais, who conducted the study along with researchers at the University of South Florida, Northern Arizona University, and Emory University.
“As high as these numbers are, they may actually underrepresent the rates of sexual coercion, since the study relied on self-reported behavior.”
Non-athletes were much less likely to believe in rape myths, such as that if a woman is drunk or doesn’t fight back, it isn’t rape, according to the study’s findings.
And non-athletes were less likely to harbor more traditional, and frequently negative, beliefs about women, such as “women should worry less about their rights and more about becoming good wives and mothers.”
The researchers also found that there was no difference between recreational and intercollegiate athletes in regard to their views toward women, belief in rape myths, or sexual behavior.
After analyzing the data, researchers found that belief in rape myths, and more traditional beliefs about women, played a key role in the increased likelihood that athletes would commit sexual assault.
“This study shows how important it is to change these attitudes,” Desmarais said.
“The ‘Attitudes Toward Women Scale’ used in the study was created in the 1970s, and includes some truly archaic, sexist items — and we still see these results today. That shows you how far we still have to go.”
Source: North Carolina State University
A new study shows that patients with psychosis, even those with a recent onset, fail to produce adequate levels of cortisol when they first wake up in the morning. The meta-analysis conducted by researchers is the first to compare cortisol levels in schizophrenia patients with their current stage of illness.
The new findings may help doctors successfully identify people who will develop full-blown psychosis among those who seek help in the early stages of the disease.
“Only some 20 to 30 percent of individuals who are at high-risk of developing psychosis due to their clinical presentation or family history actually do so. Identifying those people early is where the cortisol measurement comes in,” said associate professor Zoltan Sarnyai, of James Cook University (JCU) in Australia.
“Biomarkers are very few and far between in psychiatry, so even though a huge amount of work is still needed, this could become a valuable technique.”
For the research, scientists conducted a meta-analysis of 11 studies. A meta-analysis is a method that scientists use to combine data from multiple research studies to examine a single hypothesis. It is considered a powerful tool in scientific analysis of data pooled from multiple investigations.
Their findings reveal that patients with schizophrenia tend to have very low levels of the stress hormone cortisol just after waking up compared to healthy people.
The levels of cortisol in a person’s body upon waking is called the cortisol awakening response (CAR). Normally there is a sharp increase in cortisol levels within a few minutes of waking up in the morning. In patients with schizophrenia, however, these levels are consistently lower.
Scientists had suspected cortisol played a role in psychotic disorders for a long time, but until now, some results had been contradictory, said co-author of the study, JCU’s Dr. Maximus Berger.
“We were able to show that patients with psychosis fail to produce cortisol after they wake up in the morning. We found this even in patients with recent onset of the illness,” said Berger.
The findings provided some evidence to suggest that high-risk individuals who later develop psychosis are already experiencing changes in cortisol even before they develop the illness.
Sarnyai added that low CAR levels are also an indicator of risk for other chronic diseases and have been linked to systemic inflammation and changes in the gut flora. This means that there is potential for early diagnosis and treatment of these conditions as well.
The findings are published in Neuroscience & Biobehavioral Reviews.
Source: James Cook University
A brainwave vital-sign test may one day become just as commonplace at the doctor’s office as checking your blood pressure and heart rate, if all goes according to plan for researchers at Simon Fraser University (SFU) in British Columbia, Canada.
“We know brainwaves provide an objective physiological measurement of brain functions,” said study leader Professor Ryan D’Arcy, SFU’s BC Leadership Chair in Medical Technologies. “We’ve been working for the last 20 years to solve the major gap in terms of utilizing this for a rapid and accessible vital sign for brain function.”
Traditionally, brain waves have been measured only after trauma or disease, and the method has relied heavily on subjective, behavior-based assessments.
“However, tracking our brain’s vital signs is critically important for establishing a baseline for a person’s objective brain activity,” D’Arcy says, adding that in the event of injury or disease, it then becomes possible to determine if brain function changes, and whether treatments are effective.
The new brainwave-assessing method was developed by scientists in D’Arcy’s NeuroTech Lab, based in Surrey Memorial Hospital. They set out to develop a simple way to measure brain health over time by using non-invasive electrodes to track the brain’s electrical activity for key brain functions — in other words, the brain’s vital signs.
Using longstanding brainwave technologies, their new method makes it possible to translate complex brainwaves into objective, usable brain vital signs.
“The brain vital-sign framework described in Frontiers in Neuroscience represents the first step towards an easy way to monitor brain health,” said D’Arcy. “Potential applications are in concussion, brain injury, stroke, dementia, and other devastating brain diseases and disorders.”
Vital sign assessments are often taken in clinics, hospitals and other healthcare centers to assess the performance of various body systems.
Researchers found that it is possible to monitor brain performance during auditory sensation, and basic attention and cognitive processing.
In the paper, published in the journal Frontiers in Neuroscience, researchers describe how their new method translates complex brainwave science into clinically accessible information and demonstrates successful measurement of brain vital signs in both younger and older adults. Their method also identifies age-related brain function changes that were not evident using traditional measures.
“We describe the world’s first physiology-driven brain vital-sign measure allowing us to quantify brain vitality over time,” said Sujoy Ghosh Hajra, a Ph.D. student working with D’Arcy and the paper’s lead author.
The measuring device was developed with Mayo Clinic, Sheba Medical Centre, and the technology company HealthTech Connex.
Source: Simon Fraser University
Potentially interesting new research, albeit in mice, discovers a dietary supplement containing a blend of thirty vitamins and minerals has anti-aging properties.
The supplement — consisting of all natural ingredients widely available in health food stores — prevents and even reverses massive brain cell loss in mice, say researchers from McMaster University.
Scientists believe the formula could someday slow the progress of catastrophic neurological diseases in humans, such as Alzheimer’s, Amyotrophic Lateral Sclerosis (ALS, also referred to as Lou Gehrig’s disease), and Parkinson’s.
“The findings are dramatic,” says Jennifer Lemon, research associate in the Department of Biology and a lead author of the study.
“Our hope is that this supplement could offset some very serious illnesses and ultimately improve quality of life.”
The formula — containing common ingredients such as vitamins B, C and D, folic acid, green tea extract, cod liver oil, and other nutraceuticals — was first designed by scientists in McMaster’s Department of Biology in 2000. Nutraceuticals are foods containing health-giving additives and having medicinal benefit.
A series of studies published over the last decade and a half have shown its benefits in mice. The health enhancing effects have been demonstrated in both normal mice and those specifically bred for such research. However, research studies have not been conducted on humans demonstrating the same results.
Improvements in the mice bred for research may be especially significant as these animals are genetically altered to age rapidly, and experience dramatic declines in cognitive and motor function in a matter of months.
The mice used in this study had widespread loss of more than half of their brain cells, severely impacting multiple regions of the brain by one year of age, the human equivalent of severe Alzheimer’s disease.
The mice were fed the supplement on small pieces of bagel each day over the course of several months. Over time, researchers found that it completely eliminated the severe brain cell loss and abolished cognitive decline.
It’s important to note that the study has not yet been independently replicated by other researchers. Nor has this research shown any benefits of “anti-aging” in humans — only mice. Most mice studies when replicated in humans do not produce the same results, or the same kind of impact of the active ingredient or treatment.
“The research suggests that there is tremendous potential with this supplement to help people who are suffering from some catastrophic neurological diseases,” says Lemon, who conducted the work with co-author Vadim Aksenov, a post-doctoral fellow in the Department of Biology at McMaster.
“We know this because mice experience the same basic cell mechanisms that contribute to neurodegeneration that humans do. All species, in fact. There is a commonality among us all.”
In addition to looking at the major markers of aging, they also discovered that the mice on the supplements experienced enhancement in vision and most remarkably in the sense of smell–the loss of which is often associated with neurological disease — improved balance and motor activity.
The next step in the research is to test the supplement on humans, likely within the next two years, and target those who are dealing with neurodegenerative diseases. The research will also need to be replicated by additional researchers to demonstrate the robustness and validity of the findings.
More than four years ago, McMaster University published a similarly optimistic news article associated with some of the same researchers, Rollo and Aksenov. In the article, the researchers claimed to have found a ‘silver bullet’ supplement that could slow brain aging.
The current research is published in the journal Environmental and Molecular Mutagenesis.
Source: McMaster University/EurekAlert
New research discovers a late diagnosis of dementia can be dangerous as individuals may engage in risky activities such as driving, cooking, and managing finances and medications.
Johns Hopkin researchers studied on data from more than 7,000 older Americans and found that those who show signs of probable dementia but are not yet formally diagnosed were nearly twice as likely as those with such a diagnosis to engage in potentially unsafe activities.
An estimated 5 million people in the U.S. have some form of dementia, including Alzheimer’s disease, and the prevalence is projected to nearly triple by 2050. Multiple studies have suggested that about one-half of those with dementia are undiagnosed.
Investigators believe the findings highlight the need for families to take proactive steps to assess an individual’s cognitive capabilities to determine if a memory disorder has developed.
“When patients receive a formal dementia diagnosis, their families are typically aware that, at some point, their loved ones will not be able to drive or will need more help with their medicine,” says study leader Halima Amjad, M.D., M.P.H.
“But when people are undiagnosed, families and friends may ignore or be unaware of functional problems that already exist.”
Previous studies have clearly documented safety issues for dementia patients, Amjad notes, but have largely focused on single issues in small patient samples. For a broader look, she and her colleagues used data from 7,609 people drawn from the National Health and Aging Trends Study.
This review is an ongoing Johns Hopkins research study started in 2011 that gathers health information on Medicare beneficiaries ages 65 and older nationwide. Subjects are periodically interviewed and take cognitive and physical exams to assess their health as they age.
In the new study, Amjad’s team classified these volunteers as:
- Having diagnosed dementia if they or a companion reported that they received a formal diagnosis from a doctor,
- Or, as having probable but undiagnosed dementia if they had no formal diagnosis but scored below a certain threshold on cognitive tests or interviews with a caregiver responding on their behalf.
- Two additional groups were classified as having possible dementia or no dementia.
All participants were asked about activities or living conditions that are potentially unsafe in dementia, including providing care to another person, driving, preparing hot meals, handling finances, managing medications, going alone to doctors’ visits or multiple falls.
In addition, they answered questions about unmet needs — whether they ever went without eating, bathing, clean laundry and groceries, or stayed in the home or in bed because they had insufficient help.
Analysis showed that those with dementia, either diagnosed or undiagnosed, were less frequently engaging in potentially unsafe activities than those with possible or no dementia. For example, about 23 percent of older adults with probable dementia were driving, compared to 59 percent with possible dementia and 84 percent with no dementia.
Of older adults with probable dementia, 37 percent managed their own medications at least some of the time, compared to 93 percent of those without dementia.
“That in itself is good news, though the numbers are still important from a public health and safety standpoint,” Amjad says.
“Either the patients themselves or their family members are self-regulating and doing these activities less frequently as their disease is progressing.”
However, she says, the results revealed that those whose dementia was undiagnosed were significantly more likely to be taking part in unsafe activities, compared to those with a formal dementia diagnosis.
For example, while about 17 percent of the volunteers with diagnosed dementia were still driving, nearly 28 percent of those with undiagnosed dementia were doing so.
Similarly, about 12 percent of those with diagnosed dementia were still handling their finances, but about 29 percent of those with undiagnosed dementia were. Overall, about 17 percent of those with diagnosed dementia were still preparing hot meals for themselves, but about 42 percent of those with undiagnosed dementia were.
Moreover, nearly 22 percent of those diagnosed were still handling their own medications, while around 50 percent of those with undiagnosed dementia were.
“There are a couple of important questions we are raising in this research,” says David Roth, Ph.D., director of the Johns Hopkins Center on Aging and Health and professor of medicine at the Johns Hopkins University School of Medicine.
“First, are those with dementia receiving adequate medical care, including accurate and up-to-date diagnoses? Second, are diagnoses of dementia being properly communicated to patients and their families?”
The findings should be a wake-up call to physicians who care for the elderly and family members whose loved ones might be developing dementia, Amjad says.
“If elderly patients are having difficulty with activities, they may benefit from a physician formally screening them for dementia,” she says.
“But families are really the front line in recognizing when someone shouldn’t be driving or needs more help with managing medicines. That means being watchful and aware as loved ones get older and dementia is more likely.”
Source: Johns Hopkins Medicine
New research suggests an effect method to help overweight or obese adolescents increase their daily physical activity is to encourage use of local parks and playgrounds.
In a pilot study, investigators from Massachusetts General Hospital found use of the everyday environment was a more sustainable method to increase physical activity than organized classes or sports programs.
Investigators found use of parks and playgrounds helped overweight and obese adolescents increase their physical activity for at least three to four months. The behavioral change was facilitated by personal coaching and use of various incentives for both teens and parents.
“There is an alarming rate of obesity in this country, and we know that most kids are not getting enough physical activity,” says Nicolas Oreskovic, MD, MPH, a pediatrician and lead author of the study.
“Past efforts have not been very successful in getting kids to increase their physical activity, but as far as we know, no one has tested whether using their ‘built environment’ — parks, playgrounds, walking paths they may pass by every day — could help increase daily activity.”
Beginning in the fall of 2013, researchers enrolled 60 adolescents ages 10 to 16 who were either overweight or obese. The teens were then randomly assigned to either the intervention group or a control group.
During a week prior to their first meeting with study staff, all participants wore both a GPS device, which recorded their location, and a research-quality activity monitor that measured any moderate-to-vigorous physical activity they engaged in.
At the first study meeting control participants received a handout outlining their current activity level, based on the recorded data, along with standard recommendations regarding diet and exercise.
Intervention group participants and a parent or guardian met with Oreskovic to discuss their physical activity during the recorded week and then reviewed a map showing their home, school and locations where they had traveled during the week.
They discussed specific locations and facilities in the area that participants could use to increase their physical activity and ways they might like to do so – skipping rope in a park, skateboarding at a skate park, using walking paths or even just sidewalks to walk to and from school.
Each participant set his or her own goal for a new physical activity to achieve two or three times a week.
During the study, intervention participants received weekly text or phone messages reminding them of their goal and were also offered an incentive to achieve their new physical activity goals. The incentive was a low-cost gift — such as a ball, frisbee or jump rope awarded upon increases in physical activity.
Participants wore the GPS and activity monitors for another week one month after the first study meeting and again two or three months later. Follow-up meetings were held after each recorded week, during which participants’ progress was reviewed.
If the activity goals had been met, participants and their families received small monetary rewards. All intervention group participants competed for a more valuable prize awarded to the one who had achieved the greatest increase in moderate-to-vigorous physical activity by the final meeting.
By the third study meeting, intervention group participants had increased their average daily moderate-to-vigorous physical activity by 7.7 minutes, compared with half a minute for the control group. Overall, intervention group participants averaged 9.3 minutes more daily moderate-to-vigorous physical activity than did control group participants (38 minutes versus 28.7 minutes).
The study also looked at how many participants in each group met national guidelines for adolescents to achieve 60 minutes of moderate-to-vigorous physical activity daily. The intervention group increased from three to five participants meeting that goal, while the control group remained at only two.
Study participant Emma Forsyth, now 12, of Winthrop, Mass., enjoyed getting outdoors and being more active with her friends during the study. She took advantage of a local soccer field to increase her walking, and now has added basketball and softball to her regular activities. “I learned that it’s good to be active and healthy, and that it’s more fun to go outside and play than to sit inside and watch TV,” she says.
Her father Bill Forsyth adds, “Now whatever kind of activity we’re going to do, she automatically jumps right in and becomes involved. Many times, Emma didn’t need to go out and practice; but she did so all the same. As a parent, I’m really proud that this is something she wanted to do.”
Oreskovic comments, “Past physical activity interventions that utilized structured, sometimes artificial settings — such as school sports programs — have had very limited success because they are not easily integrated into the participant’s life and may not be sustainable. Once the study ends and the activity created for the study is no longer available, participants return to their usual habits and activities.
“Our program, in contrast, aimed to have adolescents increase their activity using existing, permanent infrastructure — which is free and available to anyone at any time — and participate in identifying activities that could be integrated into their daily lives and continued after the study ended,” he adds.
“And when participants learn to identify opportunities within their own neighborhoods, that’s a skill they can carry with them the rest of their lives and apply wherever they live — be it in Boston, Paris or Santiago.”
Study results will appear online in the Journal of Adolescent Health.
It is an accepted fact that as we age, we take less risks. New research suggests the reason we do this may be linked to a declining chemical in our brain — rather than wisdom gained through the ages.
Researchers have now discovered dopamine, a brain neurotransmitter, declines at the same rate as our daring or risk-taking tendencies.
Dopamine helps control our brain’s reward and pleasure centers and helps regulate movement and emotional responses. It enables us not only to see rewards, but to take action to move toward them.
In the study, investigators from University College London followed over 25,000 people and found that older people were less likely to choose risky gambles to win more points in a smartphone app called The Great Brain Experiment.
However, they were no different to younger participants when it came to choosing risky gambles to avoid losing points. It is widely believed that older people don’t take risks, but the study shows exactly what kind of risks older people avoid.
Investigators discovered the steady decline in risky choices with age matches a steady decline in dopamine levels. Throughout adult life, dopamine levels fall by up to 10 percent every decade.
In a prior study, researchers found that volunteers chose significantly more risky gambles to win more money when given a drug that boosted dopamine levels.
“As we age, our dopamine levels naturally decline which could explain why we are less likely to seek rewards,” explains lead author Dr. Robb Rutledge.
“The effects we saw in the experiment may be due to dopamine decline, since age was associated with only one type of risk taking and mirrored the known effects of dopamine drugs on decision making.
Older people were not more risk-averse overall, and they didn’t make more mistakes than young people did. Older people were simply less attracted to big rewards and this made them less willing to take risks to try to get them.”
The experiment involved 25,189 smartphone users aged 18-69 who played a game in The Great Brain Experiment smartphone app that involves gambling for points.
In the game, players start with 500 points and aim to win as many points as possible in thirty different trials where they must choose between a safe option and a risky 50/50 gamble.
In the ‘gain’ trials, players can either choose a guaranteed number of points or a 50/50 chance of winning more points or gaining nothing. The ‘loss’ trials are the same in reverse, where players can lose a fixed number of points or gamble with a chance of losing more points or nothing.
In the ‘mixed’ trials, players can choose zero points or to gamble with a chance of either gaining or losing points.
On average, all age groups chose to gamble in approximately 56 percent of the loss trials and 67 percent of the mixed trials. In the gain trials, 18-24 year olds gambled in 72 percent of trials and this fell steadily to 64 percent in the 60-69 age group.
In the study, researchers developed mathematical equations which provided specific predictions for how the loss of dopamine would affect decision making.
“A loss of dopamine may explain why older people are less attracted to the promise of potential rewards,” says Dr. Rutledge. “Decisions involving potential losses were unaffected and this may be because different processes important for losses are not affected by ageing.
“Political campaigners often frame voting decisions negatively, for example saying that UK households would be £4,300 worse off if the UK decides later this month to leave the EU rather than £4,300 better off if the UK decides to remain part of the EU.
Use of negative verse positive reward statements influence demographic groups in different ways.
In the above example politicians know that negative messaging helps to persuade older people, whereas a more optimistic approach that emphasizes large potential rewards might appeal more to younger people who are less likely to vote.
Our new findings offer a potential neuroscientific explanation, suggesting that a natural decline in dopamine with age might make people less receptive to the positive approach than they would have been when they were younger.”
“This study is an excellent example of the use of digital technology to produce new and robust insights into the workings of the brain. Smartphone apps allowed the researchers to capture decision-making outside of typical ‘lab’ settings, and to reach more people from varied backgrounds than is typically possible, says Dr. Raliza Stoyanova, a member of the government team at Wellcome which funded the project.
He continues, “It will be exciting to see what else the data generated from the Great Brain Experiment will reveal about risk and decision-making, as well as other complex brain processes like memory and attention.”
A new study finds that children with attention-deficit/hyperactivity disorder (ADHD) are less inclined to intuitively notice subtle rule changes relating to behavior. For example, they may have trouble detecting the unspoken rule that behavior should shift from playful to serious — such as during the transition from a game to a test — particularly when it all takes place in the same classroom. This misunderstanding often leads to inappropriate behavior.
However, explicitly explaining these otherwise unspoken rule changes will greatly improve understanding, and therefore behavior, in children with ADHD, say the team of researchers from Japan and New Zealand.
“What we argue is that, for these children, we need to make explicit what the requirements are in any given situations,” said Professor Gail Tripp, director of the Human Developmental Neurobiology Unit at the Okinawa Institute of Science and Technology Graduate University (OIST).
“So, we are not relying on them to identify what the conditions are, but we are actually explicitly telling them: this is what you will be rewarded for. And we also need to tell them when we are no longer going to reward them for that.”
“All of us tend to repeat those actions that get rewarded. That’s how we learn: we do the things that have a positive outcome for us.”
For the study, the scientists explored how children with attention deficit disorder behave when they play a game that has rules that change slightly, without explanation. The researchers tested 167 children (more than half with ADHD) between the ages of 8 and 13 in Japan and New Zealand.
All of the young participants played a simple game in which they had to decide if there were more blue or red faces on the screen in front of them. The screen showed a ten by ten grid full of mixed blue and red faces, and the children were asked to push a blue or red button according to the predominant color they saw on the screen.
The game had some specific rules. The researchers explained to the children that they were going to receive verbal praise and a plastic token when they choose the right answer — but only sometimes and not each time they choose correctly.
At first, the children were rewarded four times more often for correct ‘blue’ answers. Then, after 20 rewards, the researchers began to reward the children more often for correct ‘red’ answers. Finally, after another 20 rewards, the game switched back to rewarding more frequently for ‘blue’ answers. This change in the rewarding system was not explained to the children.
The findings reveal that, initially, the children developed a bias for blue. In fact, when in doubt, the children started to give the answer that was rewarded more often during the first part of the game.
However, when the rewarding system switched to red, differences began to emerge among the children. Kids without attention deficit hyperactivity disorder started showing a clear bias for red, while children with ADHD shifted only slightly their answers towards red.
Furthermore, when the rewarding system switched back to favoring blue, the gap in behavior widened. Typically developing children went back to more often choosing blue, while children with ADHD almost did not change their answers’ pattern.
Therefore, as the rewarding system flip-flopped between blue and red, the children had to intuitively adapt to maximize their chances to get a reward. The data suggests that children with ADHD were not as good as typically developing children at responding to such unspoken changes.
“I am really excited about this research, because I think it has important implications for how we manage the behavior of children with ADHD,” said Tripp.
Children with ADHD are not naughty children. They may appear to misbehave and they may appear not to follow the rules, but this research suggests that this happens because they are not picking up on subtle rules changes.
“Explaining the requirements in any given situation, and rewarding them accordingly, is not spoiling them,” said Tripp. “It is a good parenting strategy. It is about trying to give them the same life opportunities.”
Their findings are published in the Journal of Child Psychology and Psychiatry.
Researchers have coined a new term for the practice of observing and interpreting bits of social information that helps to understand other people’s perspectives.
The strategy is called mind-reading motivation, an approach that has strong implications for teamwork or relationships.
For instance, observing that the person next to you is rhythmically drumming his fingers may be because he’s anxious. Likewise, you may deduce that someone is preoccupied when she is gazing off into the distance.
Mind-reading motivation (MRM) is the tendency to engage with the mental states and perspectives of others. But it’s much more than just a means of passing idle time.
Being high in MRM leads to many social benefits, including better teamwork, according to Melanie Green.
Green is an associate professor in the University at Buffalo Department of Communication and the corresponding author of the a new study published in the journal Motivation and Emotion.
“We’re not talking about the psychic phenomenon or anything like that, but simply using cues from other people’s behavior, their non-verbal signals, to try to figure out what they’re thinking,” says Green.
MRM is an entirely new construct, according to those who developed it: Green and her coauthors Jordan M. Carpenter at the University of Pennsylvania and Tanya Vacharkulksemsuk at Haas School of Business, University of California, Berkeley. The researchers also believe this approach has implications for advertising and relationships.
Individuals high in mind-reading motivation enjoy speculating on others’ thoughts based on the potentially hundreds of social cues they might receive. Those low in MRM dislike or have no interest in doing so. MRM is about the motivation to engage with other minds, and is distinct from the ability to accurately interpret others’ cues.
“We didn’t measure ability directly in our study of teamwork, but the research suggests that just the motivation to understand others, and presumably the behaviors that go along with that motivation, appear to lead to benefits,” says Green.
In addition to facilitating cooperation and better teamwork, people high in MRM also consider people in great detail and have a nuanced understanding of those around them.
That is, the practice of ‘getting into someone’s’ head can have social benefits.
“Those high in MRM seem to develop richer psychological portraits of those around them,” says Green. “It’s the difference between saying ‘this person strives for success, but is afraid of achieving it’ as opposed to ‘this person is a great cook.'”
The relevance of those portraits also appears to have implications for advertising and the salience of certain messages.
“High MRM people are more drawn to and pay more attention to messages with an identifiable source – a spokesperson or an ad focusing on company values – that is, someone whose perspective they can try to understand.” says Green.
“On the other hand, low mind-reading motivation people seem to pay more attention to ads that are more impersonal, like those that just discuss the product – a message that does not appear to come from a particular person or group.”
Although there is no previous research in MRM, there is a long history of studies on perspective taking. But much of that research has focused on situations where perspective taking, in a sense, is required.
“Think about seeing some kind of trouble and trying to figure out what’s wrong,” she says. “Or noticing your partner is upset and you try to figure out what they’re thinking.”
Green and her colleagues thought there might be a difference in how much people enjoy or were motivated to speculate on people’s thoughts in situations where there was no situational need or institutional pressure. It could be as simple as a bus passenger considering the thoughts of those across the aisle.
“This hadn’t been previously considered from the standpoint of individual differences,” says Green. “That’s where this research is something new.”
Source: University of Buffalo
Online hacking costs the private and corporate sectors more than $575 billion annually. While security agencies seek out “ethical” hackers to help combat such attacks, little is known about the personality traits that lead people to pursue and excel at hacking.
New research shows that a characteristic called systemizing provides insight into what makes and motivates a hacker. Intriguingly, the personality traits are similar to many autistic behaviors and characteristics.
“We found a positive association between an individual’s drive to build and understand systems — called systemizing — and hacking skills and expertise,” said Dr. Elena Rusconi of the Division of Psychology at Abertay University in Dundee, U.K.
“In particular, we found that this drive is positively and specifically correlated with code-breaking performance.”
What is systemizing? Systemizing is the preference to apply systematic reasoning and abstract thought to things or experiences. It is theorized to exist on a continuum with a personality trait called empathizing, a preference for being agreeable and able to empathize with others. The preference for systemizing is frequently associated with autism or Asperger’s, a milder form of autism.
In the study, Rusconi’s group found that volunteer “ethical” hackers performed far above average on a series of code-breaking challenges designed to assess their systemizing skills.
According to a cognitive and behavioral survey, these hackers also self-reported characteristics that indicated a strong tendency towards systemizing.
Because of this preference for systemizing, Rusconi decided to also profile participants for other autistic-like behaviors and skills. Although none were actually autistic, hackers self-reported higher scores for attention to detail, another autism-like trait.
Researchers also found that stronger systemizing scores, but not attention to detail, correlated with more skillful code-breaking. In contrast, participants with higher attention to detail performed better on a detail-oriented task such as X-ray image screening.
These results give insight into the psychology and skill set that might predispose an individual towards a variety of security professions.
Such information could be used to improve training programs, job candidate profiling, and predictions of job performance. Furthermore, the finding that some autism-associated skills can benefit security operations may open new employment opportunities to autistic individuals.
“We are finding evidence that the positive traits of autism can predict better performance in security tasks,” said Rusconi.
“This suggests a new way to inform personnel selection in security jobs and to improve the match between individual predispositions and job assignment.”
According to a National Autistic Society estimate, only 15 percent of autistic individuals have full-time employment, although many are both willing and able to work.
Although it remains to be seen how well autistic people would perform in similar studies, Rusconi’s findings call for further exploration of the potential benefits of security occupations for these individuals, as well as the conditions that would best help them succeed.
The research appears in the journal Frontiers in Human Neuroscience.
New research finds that men who are perceived as low in masculinity by women can significantly improve this opinion by simply applying deodorant.
Interestingly, researchers discovered application of deodorant did not enhance perceptions of masculinity among men who already have high levels of masculinity. Nor does deodorant improve one’s standing with fellow men.
In the new study, researchers investigated what effect wearing deodorant has on assessing masculinity and femininity.
Researchers examined how 130 men and women rated facial masculinity and femininity using photographs. Additionally, 239 men and women rated odor samples of 40 opposite sex individuals.
The research confirmed that women appear to be, in some way, more sensitive or attentive to odor cues than men.
All women who were wearing deodorant were rated as significantly more feminine-smelling by both men and women, compared to when they had no deodorant on. This supports the idea that fragrance may be used, as other cosmetics appear to be, to enhance potentially biologically evolved preferences.
However, without deodorant men rated by women with high and low facial masculinity received significantly different ratings of odor masculinity. Then, once a deodorant was applied, the two groups of men became indistinguishable in terms of their rated levels of masculinity.
Men who were low in face masculinity significantly increased their odor masculinity by applying a deodorant, but the highly masculine men showed no increase after deodorant application.
Dr. Caroline Allen, psychology researcher at the University of Stirling, who led the study, explains that fragrances are often marketed as being feminine or masculine. “Old Spice, for instance, has recently parodied this with hyper-masculine advertisements, claiming that their product will allow you to smell like a super masculine guy.”
“Our study found that when women apply a deodorant it does increase their rated body odor femininity, as would be expected. Though it seems as though something else is at play when it comes to male body odor and male deodorants.
Only those men who were rated low in masculinity to start with showed a significant increase after applying their deodorants, and the men who were highly masculine initially showed no increase after deodorant application.
“This means that men are able to use deodorant to artificially raise their game so to speak, leveling the playing field by making themselves comparable, at least as far as odor is concerned, to more masculine men.
Our evolutionary preferences have likely shaped this difference in fragrance design. Research findings now show that we actually don’t like high levels of masculinity which are often associated with aggressiveness and hostility, but we show no upper limit on our femininity preferences.”
The new study appears in the journal Evolution and Human Behavior.
What if you could prevent clinical depression from taking hold before it’s ever even diagnosed? That’s the promise shown by an innovative European study that included a six-week online therapy and training course and support from a personal health care coach. The new research shows that participants in the online course reduced the risk of developing depression compared to those who didn’t participate in it.
Depression is a rapidly emerging public health concern across the globe. The World Health Organization expects depression to become the main cause of premature death and disease-related disability in the near future.
Experts believe that the mood disorder will become more of a burden than coronary heart disease, Alzheimer’s disease or diabetes.
The course, called GET.ON, builds on the success of numerous Web-based health interventions. It is based on established therapy methods involving systematic problem-solving and behavioral activation.
During the course, participants completed a training unit consisting of videos, texts and tasks lasting between 30 and 90 minutes each week, with elements of cognitive-behavioral and problem-solving therapy, supported by an online trainer. Study members were asked to practice what they had learned in their day-to-day lives between units.
Throughout the six weeks they also received support from their own personal coach whom they were able to contact online.
Researchers studied 406 people who were at increased risk of developing depression but were not suffering from the disorder. In their randomized clinical study, half of the test subjects took part in the GET.ON training course while the other half received standard written instructions on preventing depression.
The participants were then examined in a diagnostic telephone interview a year later. The results showed that 27 percent of the group who had completed the GET.ON course had developed depression over the course of the year, in comparison to 41 percent of the control group who did not take part in the online training.
Investigators explain that in terms of the “number needed to treat,” this means that for each six people who take part in GET.ON, one person can be prevented from developing depression. This translates to a 39 percent reduction in relative risk.
“We were able to show with the study that GET.ON can reduce the risk of depression occurring effectively,” said researcher Dr. David Ebert.
Ebert initiated the online training course and led the study and is the chair of Clinical Psychology and Psychotherapy at Friedrich-Alexander University of Erlangen-Nuremberg, Germany. “GET.ON offers people with initial symptoms a highly effective but also flexible and low-cost way of successfully preventing the development of a depressive disorder that would require treatment,” said Ebert.
The results of the GET.ON study are highly relevant for health policy.
A study by the Robert Koch Institute indicates that around 15 percent of women and 8 percent of men will suffer from depression over the course of their lives.
“Studies show that current methods of treatment are only able to reduce the suffering caused by depression by around a third,” Ebert said.
“Effective prevention strategies that provide support at an early stage are of equal importance to sufferers, the healthcare system and the economy. For this reason, Germany’s new Prevention Act has now defined the prevention of depression as an important task for the health care system for the first time. The current study shows that this is indeed a possibility with online training.”
The joint project was carried out by researchers at FAU, Leuphana University of Lüneburg and Vrije Universiteit Amsterdam carried out in collaboration with Barmer GEK.
The training course is already being offered by Barmer GEK, making it one of the first preventative measures for depression available throughout Germany.
The results are published in the May 3 issue of the Journal of the American Medical Association (JAMA).
Source: University of Erlangen-Nuremberg
A new Australian study gives us yet another reason to embrace a high-fiber diet — it helps promote “successful aging.” This is defined as the process of growing older naturally without the heavy burden of health and mental health problems, such as dementia, depression, respiratory symptoms, cancer, coronary artery disease and stroke.
“Out of all the variables that we looked at, fiber intake, which is a type of carbohydrate that the body can’t digest, had the strongest influence,” said lead author Associate Professor Bamini Gopinath, Ph.D., from the Westmead Institute’s Centre for Vision Research.
“Essentially, we found that those who had the highest intake of fiber or total fiber actually had an almost 80 percent greater likelihood of living a long and healthy life over a 10-year follow-up. That is, they were less likely to suffer from hypertension, diabetes, dementia, depression, and functional disability.”
For the study, researchers explored the link between carbohydrate nutrition and healthy aging using data gathered by the Blue Mountains Eye Study, a benchmark population-based study that examined more than 1,600 adults aged 50 years and older for long-term sensory loss risk factors and systemic diseases.
They found that out of all the factors they examined — which included a person’s total carbohydrate intake, total fiber intake, glycemic index, glycemic load, and sugar intake — it was the fiber that made the biggest impact on successful aging. Healthy fiber can typically be found in goods such as fruits (strawberries, rasberries, oranges, bananas, pears and apples), grains (cereals, breads, and pastas), nuts and seeds, and vegetables (artichokes, green pears, broccoli, turnip greens, corn, and brussels sprouts).
Although one might assume that the level of sugar intake would have made the biggest impact on successful aging, Gopinath pointed out that the particular group they examined were older adults whose consumption of carbonated and sugary drinks was already quite low.
While it is too soon to use the study results as a basis for dietary advice, Gopinath said the research has opened up a new path for exploration.
“There are a lot of other large cohort studies that could pursue this further and see if they can find similar associations. And it would also be interesting to tease out the mechanisms that are actually linking these variables,” she said.
The new findings add to the mounting evidence showing the importance of the overall diet on healthy aging.
In a similar study published last year, researchers found that, in general, adults who closely adhered to recommended national dietary guidelines reached old age with an absence of chronic diseases and disability, and had good functional and mental health status.
The new findings are published in The Journals of Gerontology, Series A: Biological Sciences and Medical Sciences.
Sexual assault has long been a serious crime problem on most college campuses. But it’s something rarely discussed by school administrators, in glossy university websites, or on new student campus tours. Sexual assault on university campuses appears to be even worse for certain sub-groups of people.
Emerging research has found that nearly 40 percent of bisexual female college students experience sexual assault after four years in college.
This incident rate is considerably more than the 1 in 4 assault rate for gay and bisexual men and heterosexual women, on college campuses.
Researchers Jessie Ford and José Soto-Marquez of New York University identified Greek life (participation in fraternities or sororities) as a factor strongly linked to a higher prevalence of sexual assault for most of the student groups studied.
“We cannot tolerate the sexual assault of any group of men or women on our college campuses,” said Violence and Gender Editor-in-Chief Mary Ellen O’Toole, Ph.D.
“Sexual assault is a very underreported crime for a wide range of reasons, and it is underreported when it occurs on college and university campuses as well.”
Sexual assault crimes are generally investigated and adjudicated by university officials, not the local police. Investigation and judicial procedures vary widely from school to school. Most schools hold disciplinary hearings, often made up of teachers and students. Unfortunately, many times the people who sit on disciplinary hearings may have little training, but nonetheless act as prosecutor, judge, and jury.
“To really understand the breadth and depth of this problem, it is critical to understand the victimology of sexual assault, and that it includes all students, not just heterosexual females,” O’Toole said.
“As difficult as it can be for any college student to come forward following a sexual assault because they are afraid, intimidated, or ashamed, it can be even more so for bisexual females and gay and bisexual males who are at risk for this crime at similar rates as heterosexual females,” according to the study’s researchers.
Given these statistics, bisexual people — especially women — should reach out to a campus assault counselor and police to report the assault and receive trauma support services. Assaults should not go unreported, as it simply reinforces the behavior and suggests the perpetrator can get away with criminal behavior.
If you need help regarding a sexual assault, please reach out to the National Sexual Assault Telephone Hotline toll-free at 800-656-HOPE (4673).
The study appears in the journal Violence and Gender.
Researchers have found that people were more likely to act on an opinion — what psychologists call an attitude — if it was labeled as moral and were more resistant to attempts to change their mind on that subject.
Andrew Luttrell, lead author of the study and a doctoral student in psychology at Ohio State University, believes the results show why appeals to morality by politicians and advocacy groups can be so effective.
“The perception that an attitude we hold is based on morality is enough to strengthen it,” Luttrell said.
“For many people, morality implies a universality, an ultimate truth. It is a conviction that is not easily changed.”
The findings show how easy it was to strengthen people’s beliefs by using the ‘moral’ label, said Dr. Richard Petty, co-author of the study and professor of psychology at Ohio State.
“Morality can act as a trigger — you can attach the label to nearly any belief and instantly make that belief stronger,” Petty said.
Other co-authors of the study were Pablo Briñol of the Universidad Autónoma de Madrid in Spain and Benjamin Wagner of St. Thomas Aquinas College.
Researchers performed an experiment in which 183 college students read an essay favoring the adoption of a senior comprehensive exam policy at their university. They were asked to provide their thoughts in response to the essay.
The students were then told by the researchers that the views they expressed seemed to be based on morality, tradition or equality.
Participants were then asked to rate how willing they would be to sign a petition in favor of the exam policy and to put their names on a list of students who favor the exam policy, and which way they would vote on the issue.
The results showed that the attitudes of students who were told that their views on the exam policy were based on morality were more likely to predict their behavior than the attitudes of students who were told their views were based on equality or tradition.
“Morality had a lot more impact than the values of tradition and equality,” Luttrell said. “Students were more likely to act on their opinion of the student exam policy if they thought it had to do with morality.”
Two other experiments involved a more universal issue: recycling. One of these studies involved college students and the other involved older adults who were not in school.
In these experiments, participants read a brief introduction to the topic of recycling and then were asked to list the thoughts they had about the issue. In this case, the researchers told the participants that their thoughts related to either morality or to the practicality of recycling. Participants then reported their attitudes toward recycling.
Nearly all of the participants had positive views on recycling. So the researchers then asked them to read a short persuasive essay with arguments against the benefits of recycling. Then, the researchers again measured the participants’ views on recycling.
Results showed that participants who were told their views on recycling were based on morality were less likely to change their minds than those who were told their views were based on practical concerns.
“People held on to their moral beliefs in a way they didn’t for other values we studied, like tradition, equality and practicality,” Luttrell said.
“But what was remarkable was how easy it was to lead people into thinking their views were based on moral principles.”
The results suggest that appeals to morality can be very effective to groups and political candidates trying to appeal to their supporters.
“People may be more willing to vote for a candidate or give money to an advocacy group if they believe it is a matter of morality,” Luttrell said. “They’re also less likely to be swayed by the opposition.”
The study is scheduled for publication in the Journal of Experimental Social Psychology.
Source: Ohio State University
Researchers have discovered a significant gap in U.S. tracking methods for childhood concussions, and current records may be vastly underestimating these injuries, according to a new study by The Children’s Hospital of Philadelphia (CHOP) and the Centers for Disease Control and Prevention (CDC).
The researchers highlight that many current counts of pediatric concussions are based solely on emergency department (ED) visits or on organized high school and college athletics data. However, among 0- to 17-year-olds in the study who were diagnosed with a concussion, only 12 percent had their first visit at the ED.
Furthermore, about one-third of the children were under 12, and would therefore not be included in any high school sports data.
In fact, the researchers found that a vast majority (82 percent) of pediatric concussion patients were first treated at a primary care site. Another 5 percent were treated within a specialty care center (sports medicine, neurology, trauma), and 1 percent were directly admitted to the hospital.
“We learned two really important things about pediatric concussion health care practices,” said Kristy Arbogast, Ph.D., lead author and co-scientific director of CHOP’s Center for Injury Research and Prevention.
“First, four in five of this diverse group of children were diagnosed at a primary care practice — not the emergency department. Second, one-third were under age 12, and therefore represent an important part of the concussion population that is missed by existing surveillance systems that focus on high school athletes.”
For the study, researchers analyzed more than 8,000 concussion diagnoses over a recent four-year period (July 2010 – June 2014) among children up to 17 years who receive their primary care within the CHOP network. Over the course of that period, primary care visits as the point of entry increased 13 percent, with a corresponding 16 percent decrease in point-of-entry ED visits.
“This study provides direction for healthcare networks and clinicians about the critical importance of providing targeted training and resources in primary care settings,” said Christina Master, M.D., a co-author and pediatric sports medicine specialist at CHOP.
“With targeted training and support, pediatric primary care providers are well-positioned to diagnose and treat the vast majority of concussions.”
Also, compared to more specialized settings, a primary care practice can see injured patients sooner, thus getting them on the proper path for treatment more quickly. With pediatric concussions, the key to recovery is early diagnosis and treatment, including early cognitive and physical rest, followed by close supervision at home.
Using this approach, the majority of concussions will heal within a few weeks. Patients with lingering symptoms or other comorbidities can be referred for specialist care.
“We need surveillance that better captures concussions that occur in children and adolescents,” said Debra Houry, M.D., M.P.H., director of CDC’s National Center for Injury Prevention and Control. “Better estimates of the number, causes, and outcomes of concussion will allow us to more effectively prevent and treat them, which is a priority area for CDC’s Injury Center.”
The findings are published in the journal JAMA Pediatrics.
A study using high-resolution functional magnetic resonance imaging (fMRI) shows that for people with depression, the region of the brain that helps us manage expectations of bad experiences reacts in an opposite manner than what occurs in healthy adults.
The University College of London study found that activity in the habenula, a pea-sized region of the brain, functions abnormally in depressed individuals.
The finding was a follow-up to the discovery that the habenula was activated in healthy volunteers when they expected to receive an electric shock.
“A prominent theory has suggested that a hyperactive habenula drives symptoms in people with depression: we set out to test that hypothesis,” said senior author Professor Jonathan Roiser.
“Surprisingly, we saw the exact opposite of what we predicted. In people with depression, habenula activity actually decreased when they thought they would get a shock. This shows that in depressed people the habenula reacts in a fundamentally different way. Although we still don’t know how or why this happens, it’s clear that the theory needs a rethink.”
The researchers scanned the brains of 25 people with depression and 25 never-depressed individuals using fMRI.
For the study, the participants were shown a sequence of abstract pictures while they lay inside the scanner.
Over time they learned that different pictures were associated with a chance of different outcomes, either good or bad. Images predicting electric shocks were found to cause increased habenula activation in healthy volunteers, but decreased activation in depressed people.
There were no differences in average habenula size between people with depression and healthy volunteers. However, people with smaller habenulae, in both groups, were found to have more symptoms of anhedonia, a loss of interest or pleasure in life.
“The habenula’s role in depression is clearly much more complex than previously thought,” said lead author Dr. Rebecca Lawson.
“From this experimental fMRI study we can draw conclusions about the effects of anticipated shocks on habenula activation in depressed individuals compared with healthy volunteers. We can only speculate as to how this deactivation is linked to symptoms, but it could be that this ancient part of the brain actually plays a protective role against depression.
“Animal experiments have shown that stimulating the habenula leads to avoidance, and it is possible that this occurs for mental as well as physical negative events.
“So one possible explanation is that the habenula may help us to avoid dwelling on unpleasant thoughts or memories, and when this is disrupted you get the excessive negative focus that is common in depression.”
The research appears in the journal Molecular Psychiatry.
A new study discovers a link between abnormalities in circadian rhythms to changes in specific neurotransmitters in people with bipolar disorder.
In a three-year study, researchers from McLean Hospital found that people with bipolar disorder have changes in the neurons which regulate anxiety and stress.
Furthermore, the alteration in the neurotransmitters that influence neuron behavior appear to be influenced by a person’s circadian rhythm.
“For more than 50 years, there’s been evidence that there’s something wrong with circadian rhythms in people with bipolar disorder, but there has been a huge gap in terms of what we understand about their brains and how altered circadian rhythms are contributing to their symptoms,” said researcher Harry Pantazopoulos, Ph.D.
Pantazopoulos is the lead author of the study and an assistant neuroscientist at McLean’s Translational Neuroscience Laboratory and an instructor in psychiatry at Harvard Medical School.
“Growing evidence points to a key role for somatostatin, a neurotransmitter in schizophrenia and bipolar disorder,” he said. “In the amygdala, a part of the brain involved in anxiety and stress, somatostatin plays an important role in the regulation of anxiety and depression, often co-occurring in these disorders.”
The paper provides three main, previously unreported findings:
- Somatostatin neurotransmitters are decreased in the amygdala in schizophrenia and in bipolar disorder;
- The amount (or expression) of somatostatin in the human amygdala is linked to healthy circadian rhythms;
- The circadian somatostatin level is altered in subjects with bipolar disorder.
This altered circadian function of somatostatin in subjects with bipolar disorder consists of a sharp decrease in somatostatin expression by neurons in the early morning.
In contrast, the level of somatostatin rises in the same neurons during this time interval in healthy control subjects.
“We eventually saw that people with bipolar disorder have a very strong decrease of this protein in the beginning of the day while people without a psychiatric disorder normally have an increase in this protein,” Pantazopoulos said.
“The decrease of the protein correlates very strongly with the established severity of depression and anxiety symptoms in people with mood disorders, in the morning. Therefore, our findings point to potential neural correlates of circadian rhythm abnormalities associated with specific symptoms in bipolar disorder.”
The study was conducted using postmortem brains from the Harvard Brain Tissue Resource Center, in which 15 brains were used from healthy controls, 15 with bipolar disorder, and 12 with schizophrenia.
“Brain imaging technology doesn’t have the resolution at the moment to allow us to examine these neurons in the brain in people with bipolar disorder because the changes are in very specific neurocircuits that we can’t visualize very well,” said Pantazopoulos.
“With postmortem brain studies, we are able to look at changes microscopically.”
While the study validates what many researchers have long suspected, Pantazopoulos is cautious about drawing conclusions.
“We’re only scratching the surface of learning what the rhythmic expression of these proteins does biologically and how this goes awry in psychiatric disorders. We have a long way to go, as this is just one brain region and one specific protein.”
Pantazopoulos recently launched a new study that looks at neurotransmitters as well as the clock genes within the suprachiasmatic nucleus of people with bipolar disorder and those without psychotic disorders. The study aimds to characterize how the proteins’ rhythm of expression change.
“From studies on animals, we know we can treat the circadian rhythm of the suprachiasmatic nucleus non-pharmacologically by using light therapy. We could potentially correct the abnormalities in circadian rhythms in some areas, such as the amygdala by resetting the circadian rhythm with bright light therapy,” said Pantazopoulos.
“The goal is to not only understand the pathology of these disorders, but to develop new diagnostic methods and treatments down the line, possibly patient-specific bright light therapy.”
The research will appear in the journal Biological Psychiatry.
Source: McLean Hospital