Progress Daily

Stimulating a mouse’s brain with a magnetic coil appears to promote the growth of new neurons in areas associated with learning and memory. If the effect is confirmed in humans, it might open up new ways of treating age-related memory decline and diseases like Alzheimer’s.

Transcranial magnetic stimulation (TMS) has been used experimentally to treat a range of brain disorders, including depression and schizophrenia, and to rehabilitate people after a stroke. TMS uses a magnetic coil to induce electric fields in the brain tissue - activating or deactivating groups of neurons, although the exact mechanism has remained unknown. One theory was that it aided learning and memory by strengthening brain circuits through a process called long-term potentiation (LTP).

Fortunato Battaglia gave mice TMS for 5 days, then analysed their brains for evidence of LTP or cell proliferation.

TMS enhanced LTP in all areas of the brain tested, by modifying key glutamate receptors so that they stayed active for longer. There wer also large increases in the proliferation of stem cells in the dentate gyrus hippocampus. These cells divide throughout life and are now believed to play a crucial role in memory and mood regulation.

“The effect on the stem cells is the most exciting finding.” Physical exercise and some antidepressants also promote neuron growth, but they can be difficult to target to specific areas.

Battaglia thinks TMS could eventually be used to improve learning and memory in people with age-related memory decline and Alzheimer’s - which is associated with a loss of neurons in the hippocampus, among other areas.

“Magnets may make the brain grow stronger,” by Linda Geddes

Turning off a gene made mice smarter in the lab.

Dr. James Bibb used genetic engineering techniques to breed mice that could be manipulated to switch off Cdk5, a gene that controls production of a brain enzyme linked to diseases marked by the death of neurons in the brain, such as Alzheimer’s.

“We have shown that we can turn off a gene in an adult animal. That has never been done before.”

Altered mice did better than normal mice in a variety of tests.

“Everything is more meaningful to these mice. The increase in sensitivity to their surroundings seems to have made them smarter.”

The smart mice were better at learning to navigate a water maze and remembering that they got a shock when they were in a certain cage.

Dr. Bibb’s work was inspired by the 1999 discovery of “Doogie” mice, a smarter breed of mice that were named after the TV program Doogie Houser.

Those mice were bred by manipulating NR2B, a gene that also plays a role in associative memory.

“It turns out Cdk5 was controlling the regulation of NR2B.”

“Maybe by finding these new mechanisms we can find new drugs that improve the cognitive performance of people who have deficits.”

Bibb is working on developing drugs that could create the same effect without the need for genetic alteration.

“There are other cases — in post-traumatic stress disorder, addiction and depression — where we may want to modulate memory not so much to improve it, but to selectively modify it to remove the negative memories that are causing the problems.”

“If all of your (brain) synapses were magically strengthened all the time, that might be good for the short term, but I’m not sure if it would be good all the time,” he said.

“Gene tweak makes mice smarter,” by Julie Steenhuysen

Jorge Moll and Jordan Grafman scanned the brains of volunteers as they were asked to think about a scenario involving either donating a sum of money to charity or keeping it for themselves.

When the volunteers placed the interests of others before their own, the generosity activated a primitive part of the brain that usually lights up in response to food or sex. Altruism, the experiment suggested, is basic to the brain, hard-wired and pleasurable.

Non-human animals sometimes sacrifice their own interests: One experiment found that if each time a rat is given food, its neighbor receives an electric shock, the first rat will eventually forgo eating.

Antonio R. Damasio has shown that patients with damage to the ventromedial prefrontal cortex lack the ability to feel their way to moral answers.

When confronted with moral dilemmas, the brain-damaged patients coldly came up with “end-justifies-the-means” answers. When confronted by a difficult issue — such as whether to shoot down a passenger plane hijacked by terrorists before it hits a major city — these patients appear to reach decisions without the anguish that afflicts those with normally functioning brains.

According to Joshua D. Greene, moral decision-making often involves competing brain networks vying for supremacy.

In one 2004 brain-imaging experiment, Greene asked volunteers to imagine that they were hiding in a cellar of a village as enemy soldiers came looking to kill all the inhabitants. If a baby was crying in the cellar was it right to smother the child to keep the soldiers from discovering the cellar and killing everyone?

The reason people are slow to answer such an awful question is that emotion-linked circuits automatically signaling that killing a baby is wrong clash with areas of the brain that involve cooler aspects of cognition. One brain region activated when people process such difficult choices is the inferior parietal lobe, which has been shown to be active in more impersonal decision-making. This part of the brain was “arguing” with brain networks that reacted with visceral horror.

Marc Hauser has found that people all over the world process moral questions in the same way. Different cultures build on that framework in much the way children in different cultures learn different languages using the same neural machinery.

“If It Feels Good to Be Good, It Might Be Only Natural,” by Shankar Vedantam

A new study from New York University shows that part of your political preference is written in your DNA. “40, perhaps 50, percent of our political beliefs seem to have a basis in genetics,” said Josh Hibbing, who contributed to the study.

Hibbing’s research [.pdf file here] showed that identical twins were more likely to share political beliefs than fraternal twins, regardless of how they were raised. DNA does not “hardwire” the belief itself, it merely affects how a person responds to a given situation. A control-happy neat-freak is far more likely to be a conservative because he or she prefers order and the comfort of the familiar, whereas a touchy-feely, globe-trotting artist is more likely to be a liberal because he or she enjoys new experiences.

“Dem or Repub? Half of the Answer is in Your Genes,” by Jen Phillips

Richard Davidson has found that the brains of monks who are the most experienced meditators are different from other brains. They have a much stronger “gamma” wave, a form of electrical activity in the brain that is associated with consciousness and pulling together information and perceptions from different regions of the brain. They also have much greater activity in the left than the right prefrontal cortex (just behind the forehead), a mark of well-being and happiness.

Meditation can change brain circuits linked to attention.

Davidson taught volunteers Vipassana meditation, in which you first focus on an object such as your breath. You then let your focus expand, and let thoughts or perceptions engage your attention, but keep yourself from reacting emotionally or judgmentally.

The volunteers practiced Vipassana meditation for three months, for 10 to 12 hours a day. Another group got only a quickie one-hour course, then practiced Vipassana for 20 minutes a day for a week. Before the training, Davidson tested the volunteers on “attentional blink.” In this glitch, if you pay close attention to one thing it’s hard to notice something that comes hard on its heels, typically within half a second. For instance, Davidson had the volunteers watch a screen where capital letters flashed, one at a time, for one-twentieth of a second. Once or twice in the rapid-fire stream of 15 or so letters, a number snuck in. At the end, the volunteers typed which number or numbers had snuck in.

In general, if a second number creeps in less than half a second after the first, you don’t notice it. The meditators significantly improved their ability to detect the second number amid the barrage of letters, even when it came less than half a second later (the period when paying attention to the first number ordinarily keeps you from noticing the second). In addition, the amount of brain activity associated with seeing the first target fell in the meditators.

“Meditating Your Way to a Better Brain,” by Sharon Begley

Only 4% of the children of mothers with college degrees are born out of wedlock. Of those who first tied the knot between 1975 and 1979, 29% were divorced within ten years. Among those who first married between 1990 and 1994, only 17% were.

Among high-school dropouts, the divorce rate rose from 38% for those who first married in 1975-79 to 46% for those who first married in 1990-94. Among those with a high school diploma but no college, it rose from 35% to 38%. And many mothers avoid divorce by never marrying in the first place. The out-of-wedlock birth rate among women who drop out of high school is 15%. Among African-Americans, it is 67%.

A large majority — 92% — of children whose families make more than $75,000 a year live with two parents (including step-parents). At the bottom of the income scale — families earning less than $15,000 — only 20% of children live with two parents.

According to Barbara Dafoe Whitehead and David Popenoe, those who marry “till death do us part” end up, on average, 4 times richer than those who never marry.

According to Avner Ahituv and Robert Lerman, married men drink less, take fewer drugs and work harder, earning between 10% and 40% more than single men with similar schooling and job histories.

Using data from a big annual survey, Lerman looked at all the women who had become pregnant outside marriage. He estimated the likelihood that they would marry, using dozens of variables known to predict this, such as race, income and family background. He then found out whether they did in fact marry, and what followed.

Among those in the bottom quartile of “propensity to marry,” those who married before the baby was 6 months old were only half as likely to be raising their children in poverty five years later as those who did not (33% to 60%).

One of the most-cited measures of prosperity, household income, is misleading over time because household sizes have changed. In 1947, the average household contained 3.6 people. By 2006, that number had dwindled to 2.6.

A study by Adam Thomas and Isabel Sawhill concluded that if the black family had not collapsed between 1960 and 1998, the black child-poverty rate would have been 28% rather than 46%. And if white families had stayed like they were in 1960, the white child poverty rate would have been 11% rather than 15%.

According to Mary Parke of the Centre for Law and Social Policy, children in single-parent homes are more than 5 times as likely to be poor as those who live with 2 biological parents (26% against 5%). Children who do not live with both biological parents are also roughly twice as likely to drop out of high school and to have behavioural or psychological problems.

If parents detest each other and quarrel bitterly, their kids may actually benefit from a divorce. Paul Amato has found that 40% of American divorces leave the children better (or at least, no worse) off than the turbulent marriages that preceded them.

Two-thirds of American children born to co-habiting parents who later marry will see their parents split up by the time they are ten. Those born within wedlock face only half that risk.

Whereas most Italians say the main purpose of marriage is to have children, 70% of Americans expect their spouse to make them happy.

“The frayed knot,” The Economist

Big, dense cities, like London, NY, and Tokyo, are good for the planet.

London, the richest region in the EU, emits 40% less carbon dioxide a person than the UK average.

Londoners produce much less household waste than anywhere else in the UK. London’s households are the most likely to have no cars, and the least likely to have two or more cars.

“Urban neutral,” by Tim Harford

A nationwide study conducted by Jay Zagorsky found no strong relationship between net wealth and IQ score.

The study is based on data from 7,403 Americans who participated in the National Longitudinal Survey of Youth.

Participants completed the Armed Forces Qualification Test (AFQT), a general aptitude test, long used as a measure of intelligence.

All participants were also surveyed about their income, total wealth, and three measures of financial difficulty: if they currently have any maxed-out credit cards, if over the past five years they had any instances where they missed paying bills, and whether they ever declared bankruptcy.

The results confirmed research by other scholars that show people with higher IQ scores tend to earn higher incomes. In this study, each point increase in IQ scores was associated with $202 to $616 more income per year.

This means the average income difference between a person with an IQ score in the normal range (100) and someone in the top 2 percent of society (130) is currently between $6,000 and $18,500 a year.

But when it came to total wealth and the likelihood of financial difficulties, people of below average and average intelligence did just fine when compared with the super-intelligent — suggesting that high-IQ people are not saving as much as others.

The percentage of people who have maxed out their credit cards rises from 7.7 percent in those with an IQ of 75 and below to a peak of 12 percent among those with an IQ of 90. Then the percentage falls in an irregular pattern to 5.4 percent among those with an IQ of 115 before rising again.

“In these measures of financial difficulties, it seems that those of slightly better than average intelligence are best off,” Zagorsky said.

“You Don’t Have to be Smart to be Rich, Study Finds,” by Jeff Grabmeier

A recent Princeton study found that boys who grew up in an intact, married family were half as likely to end up in prison as young adults. Robert Sampson observed, “Family structure is one of the strongest, if not the strongest, predictor of variations in urban violence across cities in the United States.”

In the last half-century, suicide has more than tripled among teens and young adults; one recent Harvard study found the single “most important explanatory variable” was the “increased share of youth living in homes with a divorced parent.”

One study found that young adults whose parents were divorced were nearly twice as likely to report that they had a poor relationship with their mother compared to young adults who were raised in an intact, married family (30 versus 16 percent).

On the other hand, the best social-scientific evidence suggests that children do better when their parents part ways if their relationship is characterized by serious physical or emotional abuse.

But according to Paul Amato and Alan Booth two-thirds of divorces do not involve such abuse.

“The Ring Thing,” by W. Bradford Wilcox

Until 1997, on average, 5-8% of Kerala’s total fish catch was wasted, says Robert Jensen [”The Digital Provide”; .pdf file here], who has surveyed the price of sardines at 15 beach markets. On January 14th 1997, for example, 11 fishermen at Badagara beach ended up throwing away their catches, yet on that day there were 27 buyers at markets within about nine miles who would have bought their fish. There were also wide variations in the price of sardines along the coast.

But starting in 1997 mobile phones were introduced. Coverage spread gradually, providing an ideal way to gauge the effect.

As phone coverage spread between 1997 and 2000, instead of selling their fish at beach auctions, the fishermen would call around to find the best price, while still at sea. Dividing the coast into three regions, Mr Jensen found that the proportion of fishermen who ventured beyond their home markets to sell their catches jumped from zero to around 35% as soon as coverage became available in each region. At that point, no fish were wasted and the variation in prices fell dramatically. By the end of the study coverage was available in all three regions. Waste had been eliminated and the “law of one price” had come into effect, in the form of a single rate for sardines along the coast.

Fishermen’s profits rose by 8% on average and consumer prices fell by 4% on average. Higher profits meant the phones typically paid for themselves within two months.

Leonard Waverman [”The Impact of Telecoms on Economic Growth in Developing Countries”; .pdf file here] found that an extra 10 mobile phones per 100 people in a typical developing country leads to an additional 0.44 percentage points of growth in GDP per person.

“To do with the price of fish,” The Economist