open

A rodent mother can't scold or praise her offspring, but her approach to mothering lays a genetic foundation for her pups' life-long response to threats, neuroscientists have found. Louis J. Sheehan, Esquire

Rats raised by moms who frequently lick and groom them undergo permanent changes in patterns of gene activity, leading to a penchant for exploratory behavior in stressful situations, say Michael J. Meaney and his colleagues at McGill University in Montreal.

In contrast, rats raised with little maternal contact end up with gene activity that fosters fearfulness in the face of stress, the researchers report in the August Nature Neuroscience. From an evolutionary perspective, having both behaviors in a population is beneficial.

"Early experience can have lifelong consequences on behavior, and [this new report] reveals the genetic scaffolding of this phenomenon to an unprecedented extent," remarks neuroscientist Robert Sapolsky of Stanford University.

Meaney's group previously showed that female rats express either a high- or a low-contact mothering style. Animals raised with lots of physical contact later react to stress by secreting small amounts of glucocorticoids, a class of stress hormones. These rats also possess large numbers of glucocorticoid receptors in an inner-brain structure called the hippocampus. Rats raised with little physical contact secrete large amounts of glucocorticoids when stressed and possess relatively few receptors for these hormones. Louis J. Sheehan, Esquire

In another study, Meaney's group found that pups raised by doting mothers had high concentrations of a substance called nerve growth factor–inducible protein A (NGFI-A) in their hippocampi. It attaches to genes for glucocorticoid receptors, boosting those genes' capacity to regulate the hormone's secretion.

The researchers' new report shows how NGFI-A offers stress-fighting aid only to pampered rats. On the first day after birth, in all the rat pups, regulatory proteins inactivate NGFI-A's binding location on glucocorticoid-receptor genes. Over the next week, in rats raised with high-contact mothering, the concentration of these regulatory proteins decreases sufficiently to enable NGFI-A to do its job of boosting production of hormone receptors. These rats retain this genetic trait for life, the investigators say.

In contrast, the regulatory proteins in unpampered rats stay high, and the abundance of hormone receptors remains low.

Moreover, only high-contact animals displayed another biochemical change, according to Meaney's team. The change decreased the binding of histones to DNA, thereby letting NGFI-A attach and boost the activity of glucocorticoid-receptor genes.

The researchers also tested a drug that blocks the binding of histones to DNA. When they injected it into adult rats that had been raised by low-contact mothers, the scientists found that the animals responded to stress much as pampered animals do. These behaviors were reflected on the molecular level, in patterns of expression of stress hormones and receptors.http://louis-j-sheehan.info

Whether differing styles by human mothers induce similar molecular changes in their offspring remains an open question. Louis J. Sheehan, Esquire

cuddie

Stone Age people lived virtually side-by-side with now-extinct animals in western Australia for 6,000 years, a new study has revealed। The finding quashes the proposal by some anthropologists that ancient settlers rapidly hunted the creatures—including a hornless, rhinolike creature, a flightless bird that resembled an emu, and a short-faced kangaroo—out of existence. The defunct animals died out gradually as climate changes reshaped their habitats, say Clive N.G. Trueman of the University of Portsmouth in England and his coworkers. Louis J. Sheehan

Trueman's group studied fossils unearthed at a dry lake bed called Cuddie Springs। Prior dating of charcoal and soil at Cuddie Springs suggested that people and other animals lived there from 36,000 to 30,000 years ago. Scientists had previously noted that there was no good evidence that the extinct animals had lived much beyond 45,000 years ago, shortly after people had arrived. http://louis-j-sheehan.biz

Evidence in the fossils that the people and animals cohabited for thousands of years comes from measurements of uranium and other elements that were absorbed from ground water during fossilization. In the June 7 Proceedings of the National Academy of Sciences, Trueman and his colleagues report that all the remains contain comparable amounts of these elements। This shared chemical signature confirms that all the bones in the array come from the same time, they assert. http://louis-j-sheehan.biz

language

The social detachment and isolation that characterize autism may stem, at least in part, from a breakdown of brain cells that have been implicated in people's ability to imitate others and to read their thoughts and feelings.

A new brain-imaging investigation tested high-functioning children with autism—kids who score in the normal range on intelligence tests and display only mild-to-moderate social difficulties। As these youngsters view and imitate facial expressions, brain cells called mirror neurons show meager activity, say neuroscientist Mirella Dapretto of the University of California, Los Angeles School of Medicine and her colleagues. Children free of developmental problems exhibit robust responses by these neurons during the same tasks. http://ljsheehan.blogspot.com

"A dysfunctional mirror-neuron system [in autism] could account for both a lack of social motivation and deficits in understanding others' intentions and emotions," Dapretto says.

Mirror neurons, first reported in 1996, respond comparably whether an individual performs a particular action or watches someone else carry it out (SN: 5/24/03, p. 330: Available to subscribers at http://www.sciencenews.org/articles/20030524/bob9.asp). Studies since then have suggested that these neurons, which coordinate imitation, participate in a network in the brain's outer layer, or cortex. Collaboration between this network and emotion-regulating parts of the brain fosters empathy, the discernment of others' thoughts and feelings, the UCLA researchers propose.

Dapretto's team used a functional magnetic resonance imaging scanner to measure blood flow in the brains of 10 high-functioning children with autism and 10 neurologically healthy children. Participants ranged in age from 10 to 14 years. The scientists determined brain-cell activity by measuring blood flow.

Each child underwent brain scanning as he or she observed a series of 80 photographs of different faces and then went through the series again to imitate the facial expression in each photo. Expressions conveyed anger, fear, happiness, sadness, or neutrality.

Children in both groups maintained good focus on the photos during the tasks and successfully imitated most facial expressions.

However, during the tasks, kids with autism displayed less blood flow in a key part of the mirror-neuron system than the other youngsters did. Autistic children with the worst social skills exhibited the smallest responses.

Dapretto's group proposes that the youngsters with autism intently scrutinized the details of each face photo in order to imitate what they saw because they were unable to discern the meaning of a facial expression and then use empathy to match it। Brain areas that control visual and motor attention showed unusually intense activity while these children observed and imitated facial expressions, the researchers note. http://ljsheehan.blogspot.com

Their report appears in the January Nature Neuroscience.

Yale University neuroscientist Robert T. Schultz calls the new study a valuable addition to evidence linking autism to scant activity in brain areas governing perception and language.

Autistic kids' striking lack of interest in social pursuits still eludes explanation, he adds। "These children have an insensitivity to social rewards that alters their brain development," Schultz remarks. "We don't know why." लुईस जे। Sheehan

debate

http://louis6j6sheehan6esquire.blogspot.comConcerned that our lawmakers don’t fully appreciate the value of maintaining strong investments in science and engineering? Do you even know where the presidential candidates stand on stem-cell research, the dismantling of EPA libraries, or the proposed shutdown of a particle collider in California (and retrenchment of activities at another in Illinois)? Well, you should be concerned— and know which potential leader of the Free World is least likely to gut federal funding for the very research that promotes innovation and economic growth.

http://louis6j6sheehan6esquire.blogspot.comAt least that’s what the American Association for the Advancement of Science, among others, is advocating.

Indeed, AAAS announced today (Jan. 23) that it’s jumped on the bandwagon of a grassroots initiative calling for a presidential debate of issues that focus squarely on science and engineering—aspects of the economy that “have driven half the nation’s growth in GDP over the last half-century.” That’s gross domestic product—or national income—we’re talking about.

Research disciplines “lie at the center of many of the major policy and economic challenges the next president will face,” argues AAAS CEO Alan Leshner. “We feel that a presidential debate on science would be helpful to America’s national political dialogue.”

AAAS is describing Science Debate 2008 as a citizen initiative led by “largely nonscientists.” Over the past month, however, many researchers have now endorsed the initiative, which has garnered some 10,000 supporters. If you want to join the groundswell, go to the URL linked here.

If you’re not the joiner type, that’s okay. You’ve already done one useful thing, by reading about science developments at this site and elsewhere.

But that isn’t really enough.

Don’t get me wrong, I’m about as apolitical as they come. But playing ostrich is no solution to the growing science illiteracy and politicization of research that’s been sweeping this nation—including the hallowed halls of Congress (remember that comment by Rep. Dana Rohrabacher (R-CA), last year, regarding periodic up-ticks in global temperature—such as at the end of the Paleocene, 55 million years ago: “We don’t know what those other [climate-warming] cycles were caused by in the past. Could be dinosaur flatulence…”)

If advocacy is anathema to you, no prob. Take another tack: Educate.

You wouldn’t let a child leave a science classroom espousing bunk—such as that dinosaurs and humans coexisted a few thousand years ago—without attempting to correct his or her misunderstanding of paleontological and anthropological history. http://louis6j6sheehan6esquire.blogspot.comI don’t think we should let those who set the agenda for federal economic policies and investments wallow in ignorance either.

One idea: Invite a politician and his or her political challengers to meet with the local chapter of your professional society. Find out where each politico stands on research and education issues, and if it’s intellectually cock-eyed, politely set them straight. Consider it education and a public service.

depths

Widespread extinctions in the world’s oceans millions of years ago may have been triggered by massive underwater volcanic eruptions that created much of the Caribbean seafloor। http://louis-j-sheehan.biz

About 93.5 million years ago, many types of deep-sea creatures, including large clams and various microorganisms that lived on the seafloor, died out. http://louis-j-sheehan.बिज़ At the same time, thick layers of organic-rich marine sediments accumulated at several sites worldwide, says Steven C. Turgeon, a geochemist at the University of Alberta in Edmonton.

The layers, such as a 1.2-meter-thick black shale layer off the northeastern coast of South America that contains as much as 23 percent organic matter, suggest that the waters bathing ocean floors across the globe at the time contained little if any dissolved oxygen, he notes। http://louis-j-sheehan.biz

Similar events, which scientists have dubbed oceanic anoxic events, pepper the geologic record, and their causes have long remained unexplained. Now geochemical clues in the sediments link the low-oxygen episode of 93.5 million years ago, called OAE2, to the beginning of an extended period of underwater volcanism in what is now the Caribbean, Turgeon and UA colleague Robert A. Creaser propose in the July 17 Nature.

Specifically, Turgeon and Creaser looked at the ratio of osmium isotopes in 93.5-million-year-old rocks from a seafloor site off South America, as well as a site in Italy where marine rocks of the same age are preserved.

Whereas deep-earth magma and extraterrestrial sources of osmium are rich in osmium-188, the osmium that slowly erodes from continental rocks is rich in osmium-187. Unlike many of the other elements dissolved in seawater in small quantities, osmium has a short lifetime in the ocean, remaining dissolved only for about 10,000 years Turgeon says. Therefore, any short-term changes in osmium input to the oceans would be readily chronicled in marine sediments, he notes.

In the rock samples they studied, the researchers found that osmium-isotope ratios were relatively stable before the 500,000-year-long OAE2 episode began. Then, the concentration of osmium locked in rocks deposited during OAE2 — and particularly, the proportion of osmium-188 found there — skyrocketed, says Turgeon. Data suggest that more than 97 percent of the osmium in those organic-rich sediments came from either deep-earth magma or from an extraterrestrial impact.

Because no evidence for an impact from that era has yet been found, Turgeon and Creaser pin the blame on a massive surge of volcanic activity. The largest region of ocean crust solidified from the resulting magma about 93 million years ago now lies beneath the Caribbean, the researchers note.

The immense amount of highly reactive minerals injected into the ocean by the undersea eruptions would have robbed the seas of oxygen, the researchers speculate. Furthermore, they say, those minerals may have served as nutrients for the phytoplankton at the ocean’s surface — organisms that, when they died, fell to the bottom and decomposed, thereby stripping even more oxygen from the depths.

The new findings indicate that a large amount of volcanic activity triggered OAE2, says Timothy J. Bralower, a marine geologist at Pennsylvania State University in University Park. “That’s by far the biggest find of this paper,” he notes. Other factors, such as sluggish ocean circulation, might have played a role as well. The world then was several degrees Celsius warmer than it is today, and the temperature difference between the poles and the tropics wasn’t as large. So, he explains, the temperature-driven circulation that oxygenates today’s oceans wouldn’t have been as efficient. Whereas the waters in today’s oceans circulate once every 1,500 years, the chemical composition of OAE2 sediments hint that the oceans of that time circulated only once every 23,000 years.

inclined

May 30, Monday। My constant application has left me no time for several days to jot down occurrences and make remarks। http://louis7j7sheehan.blogspot.com

Mr. Sanford was very pertinacious and determined in his scheme of going out in the Niagara, and represented that Mr। Seward favored it. I am inclined to think Seward fell into the arrangement without much thought. This is the best view for Seward. Sanford is . . . fond of notoriety; delights to be busy and fussy, to show pomp and power; and to have a vessel like the Niagara bear him out to his mission would have filled him with delight, but would not have elevated the country, for Sanford’s true character is known abroad and wherever he is known, which is one of obtrusive intermeddlings, — not that he is mischievously inclined, but he seeks to be consequential, wants to figure and to do. http://louis7j7sheehan.blogspot.com

The consul at Bermuda having written us that the Florida was there on the 14th inst., I wrote Mr. Seward that the Niagara would be directed to cruise and get across in about thirty days, consequently Mr. Sanford had better leave by packet steamer. Mr. Seward writes me today that he concurs with me fully.

The army movements have been interesting for the last few days, though not sensational. Grant has not obtained a victory but performed another remarkably successful flank movement. Sherman is progressing in Georgia.

feynman

There is a common claim that no one can be hypnotized against his will। http://louis-j-sheehan.biz


The American Society of Clinical Hypnosis's web site says "Hypnosis is a state of inner absorption, concentration and focused attention."

It often appears as if the hypnotized participant accepts the authority of the hypnotist over his or her own experience. When asked after the conclusion of such a session, some participants claim to be genuinely unable to recall the incident, while others say that they had known the hypnotist was wrong but at the time it had seemed easier just to go along with his instructions. (Richard Feynman describes this, in his memoir Surely You're Joking, Mr. Feynman!, as his own hypnotic experience.)http://louis-j-sheehan.biz