Brain activity predicts promiscuity and problem drinking | Neuroscientist News


brain reactivity

Imbalance in activation of the ventral striatum (VS on vertical scale) & amygdala, predicts problem drinking in stressed students. The same areas also predict the number of new sexual partners a person will have months after the scan. Credit: A. Knodt

       

Brain areas weigh in on risk vs. reward

A pair of brain-imaging studies suggest researchers may be able to predict how likely young adults are to develop problem drinking or engage in risky sexual behavior in response to stress.

The new research is part of the ongoing Duke Neurogenetics Study (DNS), which began in 2010 to better understand how interactions between the brain, genome and environment shape risky behaviors that can predict mental illnesses including depression, anxiety, and addiction.

“By knowing the biology that predicts risk, we hope to eventually change the biology — or at least meet that biology with other forces to stem the risk,” said the senior author of both studies, Ahmad Hariri, professor of psychology and neuroscience at Duke University.

In both studies, the team used non-invasive functional MRI imaging to measure the activity of two brain areas that help shape opposing behaviors crucial for survival: the reward-seeking ventral striatum and the threat-assessing amygdala.

In a 2012 sample of 200 DNS participants, Hariri’s group showed that having both an overactive ventral striatum and an underactive amygdala was associated with problem drinking in response to stress.

Hariri’s team confirmed this finding in the new study using a larger sample of 759 undergraduate students who averaged 19 years old.

The researchers also discovered that the inverse brain pattern — low ventral striatum and high amygdala activity — predicted problem drinking in response to stress both at the time of the scan and three months after. These results were published June 30 in Molecular Psychiatry.

“We now have these two distinct profiles of risk that, in general, reflect imbalance in the function of typically complementary brain areas,” Hariri said. “If you have high activity in both areas, no problem. If you have low activity in both areas, no problem. It’s when they’re out of whack that individuals may have problems with drinking.”

Interestingly, people with the two different risk profiles may drink for different reasons.

Hariri speculates that those with high ventral striatum activity may be motivated to drink because they are impulsive; combined with a lower danger signal coming from the amygdala, they may be less inclined to reign in their behavior.

In contrast, the participants with low ventral striatum activity usually have lower mood, and an overactive amygdala may make them more sensitive to stress, so they might drink as a coping mechanism.

Balance in the activity of the ventral striatum and the amygdala also predicts sexual behavior, according to the second study, which appeared June 10 in the Journal of Neuroscience.

In that study, a team led by graduate student Elizabeth Victor asked a subset of DNS participants (70 heterosexual men and women) how many new sexual partners they acquired over an 11-month period.

For men, the same pattern of brain activity linked to problem drinking — high ventral striatum and low amygdala activity — was associated with a greater number of sexual partners compared to those men with more balanced activity of the two brain areas.

But the pattern for more sexually active women was different: they had higher-than-normal activity in both the ventral striatum and the amygdala — indicating both high reward and high threat.

“It’s not really clear why that is,” Hariri said. “One possibility is that this amygdala signal is representing different things in men and women.”

In women, amygdala activity might be driving general awareness, arousal, and responsiveness which, when combined with strong reward-related activity in the ventral striatum, leads to a greater number of partners. In contrast, in men, the amygdala signal could be more focused on detecting danger, Hariri said.

Measuring brain-based predictors of sexual behavior is largely uncharted territory, Victor said. Although a previous study tied higher ventral striatum activity to more sexual partners, no prior studies have accounted for amygdala activity.

The next step to examine both risky sex and problem drinking is to add a third brain region: the prefrontal cortex, which is the brain’s ultimate decision-maker. This part of the brain may help the researchers predict more accurately which individuals may engage in risky behaviors.

Developing brain-based predictors is important because individuals aren’t necessarily aware of their risks, Hariri said, nor are their doctors.

“The key is that these are patterns present before problems emerge,” especially in response to stress, Hariri said. “If we know this about an individual, we can anticipate the problems and anticipate what the nature of those problems will be. This knowledge brings us one step closer to preventing the problems altogether.”

 

Advances in robots needed to explore icy moons


Advances in robots needed to explore icy moons
Credit: NASA

In December 2013, researchers using the Hubble Space Telescope announced they had found evidence of a water plume emanating from Europa’s surface.

The finding excited astrobiologists because this moon of Jupiter is widely known to have ice covering its surface. If water is escaping from the ice, that implies that there could be a way for microbial life beneath to receive energy.

The plume has not been spotted since, and scientists are still trying to figure out why this is the case. In the meantime, the possibility of plumes more generally presents an intriguing question about how best to explore them. After all, even if plumes are never spotted near Europa again, they are known to be regular occurrences on Saturn’s moon, Enceladus.

“The idea is that we can develop a sort of Swiss army knife, or instruments and exploration strategies for the , and the plumes of the icy moons,” said Nathalie Cabrol, a research scientist at SETI Institute, who recently led a presentation called “Europa and beyond: Adaptive robotic exploration of planetary plumes.”

The abstract was submitted in February at a workshop entitled, “Workshop on the Potential for Finding Life in a Europa Plume,” at the NASA Ames Research Center in Mountain View, California and co-hosted by the NASA Astrobiology Institute and the Solar System Exploration Research Virtual Institute.

Communications delays

NASA is experienced at sending spacecraft to planets far from Earth. For example, the Cassini mission, a joint project with the European Space Agency, is currently imaging Saturn and its moons. The mission has been at Saturn since 2004 and is expected to work there until 2017.

Advances in robots needed to explore icy moons
Cassini imaging scientists used views like this one to help them identify the source locations for individual jets spurting ice particles, water vapor and trace organic compounds from the surface of Saturn’s moon Enceladus. Credit: NASA/JPL

Traditionally, however, spacecraft in the Outer Solar System are unable to react to events in real time. Because they are so far away from Earth, the radio signal takes hours to reach the spacecraft and hours more to get home. This means the spacecraft do their work through long pre-programmed computer routines that are directed by ground teams on Earth.

This is even an issue on Mars, which is relatively close to our planet, with at most a 40-minute lag time between sending receiving signals, Cabrol points out.

“It’s not practical to deal with it,” she said. “The rover is spending a lot of time sitting on the surface doing nothing, which is an unproductive way of using mission time.”

The solution is to use more intelligent robots that can adapt to the environment around them, she said. This has already been tested out in challenging climates here on Earth, such as in the Andes. These robots accumulate enough data to learn what is normal and what is not normal in an environment. Also, they have programs on board to let them know what are observational priorities of the mission.

“They stay alert to what is happening around them, and they have templates on how to operate if something important is happening,” Cabrol said.

Networked intelligence

Advances in robots needed to explore icy moons
The JUpiter ICy moons Explorer mission, JUICE (Artist impression ) 

Cabrol has spent the past couple of decades working on adaptive robots in several harsh environments, ranging from the Atacama Desert in Chile to mountainous areas.

She recalled a project she is working on that involves a robotic lake explorer in Chile, which is a testbed for technologies to use on the moon Titan. The saturnian moon is considered very swampy and could contain molecules that are a precursor to life.

The robot was programmed to alert the science team if events important to the mission science objectives were occurring between planned activities. Because the test took place on Earth, the alert was sent by the robot via email. The message contained a panorama as well as physicochemical data from the air and water column. One day, as a storm occurred over the lake, Cabrol received an e-mail alert from the robot.

“I opened the window and there was a gigapan panorama showing the Lake Lander buried in the snow,” she said with a laugh. “You were right. Good job.”

To do serious exploration of a planet or moon, she added, it is a good idea to send a network of robots that would have distributed intelligence They could communicate with each other from the surface and from orbit to gather a complete picture of the area and make missions substantially more productive.

Prion trials and tribulations: Finding the right tools and experimental models


Prions are fascinating, enigmatic, and might teach us not only about rare prion diseases like Creutzfeld-Jakob disease, mad cow disease, or scrapie, but also about other more common neurodgenerative diseases. Two studies published this week in PLOS Pathogens report progress with novel tools and paradigms to study prion disease.

Several research groups have recently succeeded in generating infectious prions with prion protein produced by bacteria in test tubes under consistent and controlled conditions. Such synthetic prions are a critical tool to study how prions cause disease in general and to test the “protein-only” hypothesis, which states that the mutant prion protein itself can trigger the disease by co-opting other prion proteins to form aggregates that are toxic to nerve cells. Jiyan Ma, from the Van Andel Research Institute in Grand Rapids, USA, and colleagues tested whether the properties of synthetically generated prions are the same as those of natural disease-causing prions, and whether the disease caused by synthetic prions is identical to naturally occurring prion disease.

They demonstrate that similar to the classical disease-causing prions, synthetic prions are infectious in a concentration-dependent way, and are able to cause prion disease in normal mice not only by direct injection into the brain (which is the easiest but not a naturally occurring way of prion transmission) but also by other routes. The researchers also show that the synthetic prions induced pathological changes typical for classic prion disease, including the dissemination of disease-specific prion protein accumulation and the route and mechanism of invasion of nerve cells in the brain. They conclude that their results “demonstrate the similarity of synthetically generated prion to the infectious agent in TSEs [transmissible spongiform encephalopathies, another term for prion diseases] and provide strong supporting evidence for the prion hypothesis.”

About 15% of human prion disease is heritable and caused by dominant mutations in the human PRP gene. The mutations are thought to predispose the resulting PRP protein proteins to adapt the disease conformation and trigger the cascade that kills nerve cells. Much of the study of inherited human prion disease in mice has focused on mixing mutant human prions–isolated from human patients or produced by transgenic mice carrying the mutant human gene–with normal mouse prions in order to establish whether the mutant human prions are infectious, i.e. whether they can change normal proteins to the disease-associated conformation (or shape).

John Collinge, from University College London, UK, and colleagues answered a crucial question regarding such studies, namely whether superimposition of pathogenic human PrP mutation into mouse PrP (which is similar but not identical) will have the same structural consequences as occur in the human brain. They focused on a specific mutation underlying an inherited form of human prion disease called Gerstmann-Sträussler-Scheinker (GSS) disease. This mutation causes an amino-acid substitution (proline-to-leucine) in the prion protein, human PrP 102L for short. In the brain of patients with GSS disease, this mutant prion (GSS-102L) co-exists with a heterogeneous mixture of normal PrP and other PrP derivatives, which it somehow manages to co-opt into forming aggregates that are toxic to the nerve cells.

To characterize the transmission capabilities of the GSS-associated prions, the researchers tested whether the ability of GSS P102L to cause prion disease in mice depended on what other types of prion proteins and derivatives were present. They examined whether GSS P102L prions could infect transgenic mice that express human mutant 102L PrP, human normal PrP, or normal mouse PrP. Injecting a pure preparation of GSS P102L prions into the brains of the three different types of mice, they found that GSS P102L prions can only infect transgenic mice expressing human 102L PrP, i.e. those carrying the identical mutant human gene. Mice expressing normal human PrP or normal mouse PrP were completely resistant to infection with GSS-102L prions.

“Collectively”, the researchers say, their data “establish that GSS-102L prions which replicate with high efficiency in a host expressing human PrP 102L are unable to propagate using wild-type [normal] human PrP or wild-type mouse PrP as substrate.” These results differ from the reported transmission properties of prions generated in GSS-P102L challenged mice expressing mouse PrP 101L (the equivalent mutation in the closely related but not identical mouse PrP): such prions readily infect animals expressing normal human or normal mouse PrP. Commenting on the discrepancy, the researchers suggest that the superimposition of the human on the mouse mutation might have generated experimental prion strains with different transmission characteristics from those of authentic human prion strains. Overall, they conclude that “future transgenic modeling of infectious prion diseases should focus exclusively on expression of mutant human PrP, as other approaches may generate novel experimental prion strains that are unrelated to human disease.”

Better tools and better paradigms to study prion diseases should help the understanding of how these diseases spread and devastate mammalian brains, and eventually lead to efficient treatment and prevention strategies.

Animal that can survive in space


http://www.sciencedump.com/content/animal-can-survive-space

Tardigrades or “Water Bears” are the only creatures that can survive the extreme conditions in the vacuum of outer space.

A Randomized, Controlled Trial of 3.0 mg of Liraglutide in Weight Management — NEJM


Background

Obesity is a chronic disease with serious health consequences, but weight loss is difficult to maintain through lifestyle intervention alone. Liraglutide, a glucagon-like peptide-1 analogue, has been shown to have potential benefit for weight management at a once-daily dose of 3.0 mg, injected subcutaneously.

Methods

We conducted a 56-week, double-blind trial involving 3731 patients who did not have type 2 diabetes and who had a body-mass index (BMI; the weight in kilograms divided by the square of the height in meters) of at least 30 or a BMI of at least 27 if they had treated or untreated dyslipidemia or hypertension. We randomly assigned patients in a 2:1 ratio to receive once-daily subcutaneous injections of liraglutide at a dose of 3.0 mg (2487 patients) or placebo (1244 patients); both groups received counseling on lifestyle modification. The coprimary end points were the change in body weight and the proportions of patients losing at least 5% and more than 10% of their initial body weight.

Results

At baseline, the mean (±SD) age of the patients was 45.1±12.0 years, the mean weight was 106.2±21.4 kg, and the mean BMI was 38.3±6.4; a total of 78.5% of the patients were women and 61.2% had prediabetes. At week 56, patients in the liraglutide group had lost a mean of 8.4±7.3 kg of body weight, and those in the placebo group had lost a mean of 2.8±6.5 kg (a difference of −5.6 kg; 95% confidence interval, −6.0 to −5.1; P<0.001, with last-observation-carried-forward imputation). A total of 63.2% of the patients in the liraglutide group as compared with 27.1% in the placebo group lost at least 5% of their body weight (P<0.001), and 33.1% and 10.6%, respectively, lost more than 10% of their body weight (P<0.001). The most frequently reported adverse events with liraglutide were mild or moderate nausea and diarrhea. Serious events occurred in 6.2% of the patients in the liraglutide group and in 5.0% of the patients in the placebo group.

Conclusions

In this study, 3.0 mg of liraglutide, as an adjunct to diet and exercise, was associated with reduced body weight and improved metabolic control.

New study points to link between blue eyes, alcoholism.


  • New research out of the United States is pointing to a connection between blue eyes and alcoholism.According to the new study, people with blue eyes have a higher tendency to abuse alcohol than people with darker eyes.
  • The University of Vermont study published in the July issue of theAmerican Journal of Medical Geneticsfound a correlation between European American people with light-coloured eyes like blue, green, grey and light brown – have a higher tendency of alcoholism, with the highest levels of alcoholism found among subjects who had blue eyes.

    It seems simple and Dawei Li, an assistant professor at the school, and one of the study’s authors, admitted that “we still don’t know the reason” why the light colours are associated with heavy drinking.

    But the results do suggest “an intriguing possibility,” he said in a press release.

    Li’s co-author Arvis Sulovari said it does suggest “an intriguing possibility – that eye colour can be useful in the clinic for alcohol dependence diagnosis.”

    The study’s results were borne out of a database of more than 10,000 people who had been diagnosed with at least one form of psychiatric illness, including depression, and schizophrenia, as well as drug and alcohol addiction.

    From that database, the study’s authors filtered out 1,263 alcohol-dependent people and retested three times after noticing the connection to eye colour.

    It’s not the first time scientists have looked at the eye’s association with alcohol. A 2000 study also noted that people with lighter eyes are “more likely than dark-eyed individuals to abuse alcohol.”

    That study suggested the higher consumption was linked with greater alcohol tolerance among people with light eyes.

    Are blue-eyed people more likely to consume large amounts of alcohol? One study says yes.

 

Being overweight INCREASES chances of surviving cancer, study finds


 

  • Study examined BMI and survival rates for patients with colorectal cancer
  • Those with lowest BMI from 20 to 24.9, survived 21.1 months after chemo
  • Overweight patients, with a BMI of 25 to 29, survived 23.5 months while obese patients with a BMI of 30 to 35 survived for two years
  • Experts believe thinner patients could have a lower ability to tolerate gruelling chemotherapy treatment

 

Overweight cancer patients are more likely to survive after treatment for advanced stages of the disease, new research has revealed.

Doctors branded their findings a ‘surprise’, having expected thinner patients to fare better.

Their study found patients with a low to healthy body mass index (BMI) lived on average two-and-a-half months less than overweight and obese patients.

The results shocked researchers, who had predicted obese patients would not react as well to treatments for stage 4 colorectal cancer because of their increased risk of developing the disease and it returning.

Scientists said they were surprised to discover overweight and obese cancer patients are more likely to survive longer after treatment for advanced stages of the disease than their thinner counterparts

Scientists said they were surprised to discover overweight and obese cancer patients are more likely to survive longer after treatment for advanced stages of the disease than their thinner counterparts

Past research has also shown many obese cancer patients receive less-than-optimal dosages of cancer drugs, or have other health problems that complicate their recovery.

Lead author of the new study, Dr Yousuf Zafar, of Duke University in North Carolina, said: ‘Contrary to our hypothesis, patients who had the lowest BMI were at risk for having the shortest survival.

‘In this case, patients with the lowest body weight – people who had metastatic colon cancer [that which had spread] and a BMI of less than 25 – were at the highest risk.’

According to guidelines, a healthy adult’s BMI ranges from 18.5 to 24, while a BMI below 18.5 is deemed underweight.

Researchers examined data from 6,128 patients who had previously been untreated for their metastatic colorectal cancer, from four different studies in the US and Europe.

Their average BMI at the start of cancer treatment was 25.3, considered slightly overweight.

All received the drug bevacizumab with chemotherapy as part of their treatment.

Bevacizumab, also known by the brand name Avastin, is used in patients with metastatic cancer to slow the growth of new blood vessels.

Researchers divided patients into four BMI ranges, and measured participants’ survival rates.

A study into patients battling colorectal cancer found those classified obese or overweight by their BMI survived up to three months longer

A study into patients battling colorectal cancer found those classified obese or overweight by their BMI survived up to three months longer

They also measured the length of time that patients’ tumours stopped growing, which was measured as progression-free survival.

Patients with the lowest BMI from 20 to 24.9, which would be considered a healthy weight according to BMI guidelines, survived an average of 21.1 months after starting their treatment.

Those with a BMI of 25 to 29, considered overweight, survived two-and-a-half months longer, researchers found.

Furthermore, obese patients seemed to fare best.

Patients deemed obese with a BMI of 30 to 35, survived an average of 24 months.

And those with BMIs of 35.1 and higher, survived an average of 23.7 months.

Although the study found significant differences in how long a patient lived based on their BMI ranges, patients of all weights saw similar rates of progression-free survival, or a halt in their tumour growth.

Patients whose tumours stopped growing went an average of 10 months without progression, but the stoppage in tumour growth does not necessarily improve chances of survival.

The study does not indicate that being overweight is in any way protective for patients undergoing cancer treatment, Dr Zafar said.

Instead, the results suggest that there could be an aspect of biology that could put thinner patients at a higher risk for poor outcomes, he said.

Dr Zafar said: ‘There may be a relationship between having a lower BMI and how much treatment patients can tolerate.

‘I would hypothesise that the lowest weight patients in our analysis received or tolerated less treatment, or received adequate treatment at first, but became too sick to receive additional therapy.

‘That may be where we can focus more attention on improving their outcomes.’

The study was presented at the European Society for Medical Oncology World Congress on Gastrointestinal Cancer.

 

 

The universe won’t end with the Big Crunch but the Big Rip, scientist claims


If the thought of the universe collapsing in on itself wasn’t bleak enough, a new theoretical model envisions something even more apocalyptic – every atom being ripped apart.

The Big Rip would see everything from galaxies to planets to moons to matter to space-time itself torn apart, a conclusion to the generally accepted Big Bang theory that wouldn’t happen for around 22 billion years.

“The idea of the Big Rip is that eventually even the constituents of matter would start separating from each other,” Dr Marcelo Disconzi, the mathematician leading the work at Vanderbilt University in Tennessee, told The Guardian.

The cosmological hypothesis states that the altering ratio between dark energy pressure and its energy density in the universe would lead to it being pulled apart.

“You’d be seeing all the atoms being ripped apart, it’s fair to say that it’s a dramatic scenario,” he added, putting it lightly.

The idea was first put forward in 2003, with Dartmouth College’s Robert Caldwell calculating the time from the present to the end of the universe to be:

This would put us about a third of a way through existence as we know its lifespan, with the Big Bang thought to have occurred 13.8 billion years ago.

Disconzi admits he is not certain about his theory however.

“The only thing we definitely know is that the universe is expanding and that the rate is accelerating,” he said. “That’s about the only thing we know for sure.”

Other theories for the ultimate fate of the universe include the Big Freeze, the Big Bounce, heat death and a multiverse with no complete end.

‘Digital amnesia’: Internet has made everyone forget everything


People are forgetting important information because they’ve handed over responsibility for remembering it to their phones, a new study has found.

Most people can’t remember the phone numbers of their children or their schools, or their work, the study by Kaspersky found. But 47% of people could remember their home phone number between the ages of 10 and 15.

The forgetting seems to be a consequence of people never needing to remember because the information is always accessible on a phone, with 53% of young people saying that their smartphone has all the information they need to know.

Mobile

The effect, called “digital amnesia” by the cybersecurity company, applies across all age groups and equally between men and women, it said.

As we give over the power of information to our devices, the risk of losing them becomes greater, the study found. Among women, 44% would be “overwhelmed by sadness” if they lost their devices and so lost memories they might never get back. A large number of women and young people would “panic”, since their devices are the only places they store their important data.

Novel Programs and Discoveries Aim to Combat Antibiotic Resistance


In the wake of increasing antimicrobial resistance threats, this article discusses some recent government initiatives and efforts by scientists, physicians, and public health officials to combat drug-resistant bacteria.

With increasing concerns over the continued development of bacterial resistance to antibiotic drugs, researchers and public health officials are conducting and supporting new initiatives to develop novel antibiotics and to discover the mechanisms involved with resistance in bacteria that cause urinary tract infections, pneumonia, bloodstream infections, and others.

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