Tag: study
Stress Reaction May Be In Your Dad’s DNA, Study Finds

Stress Reaction May Be In Your Dad’s DNA, Study Finds

By Geoffrey Mohan, Los Angeles Times (TNS)

Stress in this generation could mean resilience in the next, a new study suggests.
Male mice subjected to unpredictable stressors produced offspring that showed more flexible coping strategies when under stress, according to a study published online Tuesday in the journal Nature Communications.

The secret might be hidden in a small change in how certain genes are regulated in the sperm of the father and in the brains of offspring, the study found.

Several studies have shown that stress in early life not only can affect the individual’s behavior and cognitive functions, but can affect the next generation. So researchers have been eager to find any trace of changes in DNA coding that might underlie their observations.

Before you pen a “thanks for the resilience” Father’s Day card, consider: The study involved mice, not humans. More important, even the seemingly more resilient mice had lots of negative behaviors — depression and anti-social tendencies among them.

“If we look at the whole behavior of these animals, the benefit is really a very small proportion of the effects,” said study co-author Isabelle Mansuy, a neuroscientist at the University of Zurich’s Brain Research Institute. “Most other effects are fairly negative, because the animals are depressed, are anti-social, and have cognitive impairment.”

Researchers tried to mimic the effects of erratic parenting and a stressful home environment. So they separated male mouse pups from their mothers for several hours a day over the first two weeks of life, during which time they were occasionally restrained or forced to swim for five minutes — all at unpredictable intervals.

The mice then matured in social groups of four or five unrelated mice of the same sex that had equally unpredictable childhoods. Then they were matched to females, producing pups of their own. Once the pups grew up, they were subjected to various mazes that test the ability to show goal-oriented and flexible behavior under stress.

Compared with a control group, the offspring of stressed dads showed less hesitation in exploring an arm of a maze. And when offered the choice of getting a drink of water immediately or waiting for sugared water, the offspring of stressed males tended to wait for the greater reward. They also were better at figuring out changed rules — rewards that were moved from one spot to another, or cues that were changed.

Numerous studies of the effects of stress implicate a loop in the brain’s limbic system, which mediates emotion and causes the release of the stress hormone cortisol. That chemical can amp up a feedback loop to the brain.

Much of this stress-related reaction in the brain is mediated, in part, by a mineralocorticoid receptor, or MR, in brain cells.

The study found small changes in regulatory DNA sequences near an MR gene in sperm cells of the stressed mice. Such changes in gene regulation in response to the environment are known as epigenetic processes. The study found epigenetic markers associated with a half-dozen genes in the brain cells in the hippocampus of the offspring of stressed male mice.

Together, these changes offer a hint at a possible path for passing the effects of stress from one generation to the next.

Soldiers may offer a prime example, Mansuy said. “Many soldiers are people from lower socioeconomic environments and many of them have been exposed to violence, to broken families and to bad conditions when they were young,” she said. “And many of these people are stress-resilient, and they also have some adaptive advantages when they are placed in a situation of danger or challenge. They have developed coping strategies perhaps that other people have not.”

Still, she noted, these enhanced resiliency behaviors were “the only benefit” observed among the mice.

Researchers have been trying to untangle the effects of genetics and family background in post-traumatic stress disorder among soldiers returning from war.

Photo via WikiCommons

Partisans Segregate Themselves In Separate News Universes, Study Finds

Partisans Segregate Themselves In Separate News Universes, Study Finds

By David Lauter, Tribune Washington Bureau

WASHINGTON — Die-hard liberals and down-the-line conservatives have segregated themselves into strikingly different news universes, relying on sources of information that often reinforce their views and discussing politics mostly with others of like minds, according to an in-depth new study.
Although few people manage to live in a complete ideological bubble, the most politically active and aware Americans – the ones who dominate election contests, particularly primaries, and drive discussions of political issues – have gone far in that direction, according to the data from a Pew Research Center project on political polarization and the media.
The roughly 1 in 5 Americans with consistently liberal or conservative views, based on a 10-question scale of political opinions, rely on very different sources of news and information, and nearly all the sources trusted by one side are heavily distrusted by the other.
And on both sides, half or more of ideologically consistent Americans say most of their friends share their views.
Nearly half of consistent conservatives (47 percent) named Fox News as their main source of information about government and politics, and 84 percent said they got news from the cable channel in the week they were surveyed.
No single source dominates the audience on the left the way Fox dominates the right. CNN, MSNBC, NPR, and the New York Times each were cited by 10 percent or more of consistent liberals as their chief sources of political and government news. Just over half of consistent liberals said they had gotten news from NPR or CNN in the week of the survey. Almost no consistent liberals cited Fox as their main source of news.
Consistent liberals overwhelmingly said they distrust Fox, and only 3 percent of consistent conservatives said they trusted the New York Times or NPR.
The survey’s finding about Fox‘s overwhelming reach among conservatives dovetails with a 2012 USC Annenberg/Los Angeles Times poll, which found that nearly half of Republicans turned to Fox at least daily. Because of its ubiquity among conservatives, getting coverage on Fox has become crucial for Republican political candidates.
Among 36 news sources in the survey, including print, online, and broadcast outlets, liberals rated 28 as more trusted than not, and conservatives trusted just eight, including Rush Limbaugh, the radio talk show host, and the online Drudge Report.
Only the Wall Street Journal, which combines a mainstream news report with a conservative editorial page, was rated as more trusted than not by people across the ideological spectrum. At the other end of the scale, one source, BuzzFeed, was more distrusted than trusted by liberals as well as conservatives and those in between, although only about one-third of those responding to the survey had heard enough about the site to have an opinion.
About many news sources, liberals and conservatives disagreed overwhelmingly. By 81 percent to 6 percent, for example, consistent liberals said they distrusted Fox; consistent conservatives trusted the cable news channel by 88 percent to 3 percent. Although only 3 percent of consistent conservatives said they trusted either the New York Times or NPR, among consistent liberals, 72 percent trusted NPR and 62 percent trusted the New York Times.
Among respondents overall, 54 percent said they trusted CNN and 50 percent trusted ABC and NBC news. No other sources were trusted by half or more of respondents, in part because many of them were not widely recognized. CBS was trusted by 46 percent overall.
The Journal‘s audience comes about equally from each part of the ideological spectrum, the survey indicated. Many other programs, websites, and other sources that people use for political information have audiences that tilt strongly in one direction or the other. Nearly three-quarters of the audience for Comedy Central’s “The Daily Show With Jon Stewart,” for example, holds consistently or mostly liberal views. More than 80 percent of Rush Limbaugh’s audience holds consistently or mostly conservative views.
The polarization of information sources also extends to friends. Two-thirds of consistent conservatives and about half of consistent liberals said that most of their close friends shared their political views. Among consistent liberals, about one-quarter said they had stopped talking to or being friends with someone because of politics. About 1 in 6 of consistent conservatives said the same.
When asked to list three people with whom they discuss politics, half of consistent conservatives listed only people whom they identified as conservative. Just under one-third of consistent liberals listed only other liberals.
Americans who have more mixed political views don’t pay nearly as much attention to politics as those on either extreme, don’t talk about it as much with friends or family and don’t participate as much. When they do seek out news about politics and government, they rely on a more mixed array of news sources, the survey found.
Similar patterns hold true in the way people use social media, the survey found. About half of all those surveyed said that they encountered some news about government or politics on Facebook. But those who held ideological consistent views, either on the right or the left, were much more likely to pay attention to those items.
The ideologically committed were also more likely to see mostly items online that reflected their own views, largely because they are more likely to have ideologically compatible friends.
Among Americans overall, just over 1 in 5 said all or most of the posts about politics they see on Facebook are in line with their own views. But among consistent conservatives, almost half said that. Among consistent liberals, about one-third did.
The Pew study was based on an online survey this spring of 2,901 respondents selected to reflect overall U.S. demographics. The data have a margin of sampling error of plus or minus 2.3 percentage points.

Photo by Totenkopf/Wikimedia Commons

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Study: IQ, Exposure To Violence Could Predict Which Kids Will Commit Murder

Study: IQ, Exposure To Violence Could Predict Which Kids Will Commit Murder

By Sarah Mervosh, The Dallas Morning News

DALLAS — These days, experts more or less understand what puts kids at risk for becoming criminals: using drugs, carrying a gun, even just believing that they will die young.
But predicting who will commit murder? Not so easy.
A new study by a University of Texas at Dallas criminologist found that it’s nearly impossible to predict which juveniles will become murderers. Only two factors distinguished them from other offenders: lower IQ and a greater exposure to violence.
But even more notable was what the study didn’t find. Mental health issues and drug use — two popular narratives to explain crime — didn’t predict which youth offenders would commit homicide.
“It’s not always the way people think it is. In fact, with respect to homicide, it’s nothing the way people think it is,” said Alex Piquero, a UTD criminologist and an author of the study.
Piquero studied about 1,350 serious juvenile offenders (mostly felony offenses) and found that just 18 had been charged with a homicide offense. Those offenders had an IQ of about 79, compared to about 85 in the other offenders. They also were more likely to have been exposed to violence, such as having been in a dangerous situation or witnessing an assault or rape.
“Almost everything else doesn’t matter,” Piquero said. “You always hear on TV that this person had mental illness or this person had this psychological problem. The world’s full of people who have a lot of mental illness or psychological problems, but most of them never commit homicide.”
The unpredictability of murder could help explain why they happen, Piquero said.
“Our best guess is they are situationally driven,” he said. “They are assaults and drug deals gone bad.”
The lesson, Piquero said, is to focus on improving childhood education and reducing neighborhood violence. “We all benefit from having a higher IQ and less violent society,” he said.

Photo via Rob Bixby via Flickr

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