Tuesday, May 27, 2008

Memory Loss - Aging - Alzheimer's Disease - Aging Brains Take In More Information, Studies Show - Health - NYTimes.com

Memory Loss - Aging - Alzheimer's Disease - Aging Brains Take In More Information, Studies Show - Health - NYTimes.com

“For the young people, it’s as if the distraction never happened,” said an author of the review, Lynn Hasher, a professor of psychology at the University of Toronto and a senior scientist at the Rotman Research Institute. “But for older adults, because they’ve retained all this extra data, they’re now suddenly the better problem solvers. They can transfer the information they’ve soaked up from one situation to another.”

Such tendencies can yield big advantages in the real world, where it is not always clear what information is important, or will become important. A seemingly irrelevant point or suggestion in a memo can take on new meaning if the original plan changes. Or extra details that stole your attention, like others’ yawning and fidgeting, may help you assess the speaker’s real impact.

“A broad attention span may enable older adults to ultimately know more about a situation and the indirect message of what’s going on than their younger peers,” Dr. Hasher said. “We believe that this characteristic may play a significant role in why we think of older people as wiser.”

In a 2003 study at Harvard, Dr. Carson and other researchers tested students’ ability to tune out irrelevant information when exposed to a barrage of stimuli. The more creative the students were thought to be, determined by a questionnaire on past achievements, the more trouble they had ignoring the unwanted data. A reduced ability to filter and set priorities, the scientists concluded, could contribute to original thinking.

This phenomenon, Dr. Carson said, is often linked to a decreased activity in the prefrontal cortex. Studies have found that people who suffered an injury or disease that lowered activity in that region became more interested in creative pursuits.

Jacqui Smith, a professor of psychology and research professor at the Institute for Social Research at the University of Michigan, who was not involved in the current research, said there was a word for what results when the mind is able to assimilate data and put it in its proper place — wisdom.

Saturday, May 03, 2008

Religion a figment of human imagination - being-human - 28 April 2008 - New Scientist

Religion a figment of human imagination - being-human - 28 April 2008 - New Scientist

Humans alone practice religion because they're the only creatures to have evolved imagination.

That's the argument of anthropologist Maurice Bloch of the London School of Economics. Bloch challenges the popular notion that religion evolved and spread because it promoted social bonding, as has been argued by some anthropologists.

Instead, he argues that first, we had to evolve the necessary brain architecture to imagine things and beings that don't physically exist, and the possibility that people somehow live on after they've died.

Once we'd done that, we had access to a form of social interaction unavailable to any other creatures on the planet. Uniquely, humans could use what Bloch calls the "transcendental social" to unify with groups, such as nations and clans, or even with imaginary groups such as the dead. The transcendental social also allows humans to follow the idealised codes of conduct associated with religion.

"What the transcendental social requires is the ability to live very largely in the imagination," Bloch writes.

"One can be a member of a transcendental group, or a nation, even though one never comes in contact with the other members of it," says Bloch. Moreover, the composition of such groups, "whether they are clans or nations, may equally include the living and the dead."

Modern-day religions still embrace this idea of communities bound with the living and the dead, such as the Christian notion of followers being "one body with Christ", or the Islamic "Ummah" uniting Muslims.
Stuck in the here and now

No animals, not even our nearest relatives the chimpanzees, can do this, argues Bloch. Instead, he says, they're restricted to the mundane and Machiavellian social interactions of everyday life, of sparring every day with contemporaries for status and resources.

And the reason is that they can't imagine beyond this immediate social circle, or backwards and forwards in time, in the same way that humans can.

Bloch believes our ancestors developed the necessary neural architecture to imagine before or around 40-50,000 years ago, at a time called the Upper Palaeological Revolution, the final sub-division of the Stone Age.

At around the same time, tools that had been monotonously primitive since the earliest examples appeared 100,000 years earlier suddenly exploded in sophistication, art began appearing on cave walls, and burials began to include artefacts, suggesting belief in an afterlife, and by implication the "transcendental social".

Once humans had crossed this divide, there was no going back.

"The transcendental network can, with no problem, include the dead, ancestors and gods, as well as living role holders and members of essentialised groups," writes Bloch. "Ancestors and gods are compatible with living elders or members of nations because all are equally mysterious invisible, in other words transcendental."
Nothing special

But Bloch argues that religion is only one manifestation of this unique ability to form bonds with non-existent or distant people or value-systems.

"Religious-like phenomena in general are an inseparable part of a key adaptation unique to modern humans, and this is the capacity to imagine other worlds, an adaptation that I argue is the very foundation of the sociality of modern human society."

"Once we realise this omnipresence of the imaginary in the everyday, nothing special is left to explain concerning religion," he says.

Chris Frith of University College London, a co-organiser of a "Sapient Mind" meeting in Cambridge last September, thinks Bloch is right, but that "theory of mind" – the ability to recognise that other people or creatures exist, and think for themselves – might be as important as evolution of imagination.

"As soon as you have theory of mind, you have the possibility of deceiving others, or being deceived," he says. This, in turn, generates a sense of fairness and unfairness, which could lead to moral codes and the possibility of an unseen "enforcer" - God – who can see and punish all wrong-doers.

"Once you have these additions of the imagination, maybe theories of God are inevitable," he says.

Friday, May 02, 2008

Study identifies new regulator of fat metabolism

Study identifies new regulator of fat metabolism

Study identifies new regulator of fat metabolism
Over the past several years, animal studies have shown that high-fat, low-carbohydrate “ketogenic” diets cause demonstrable changes in metabolism and subsequent weight loss. Now, researchers at Beth Israel Deaconess Medical Center (BIDMC) have identified a key mechanism behind this turn of events. Their findings, which appear in the June 2007 issue of Cell Metabolism, demonstrate that a liver hormone known as FGF21 is required to oxidize fatty acids – and thereby burn calories.

[...]

"When the diet is extremely low in starches and sugars, blood sugar levels drop substantially so that muscle and brain have to turn to alternative fuels,” explains senior author Eleftheria Maratos-Flier, MD, an investigator in the Department of Endocrinology, Diabetes and Metabolism at BIDMC and Associate Professor of Medicine at Harvard Medical School. “Consequently, fatty acids are broken down in the liver and converted to ketones, which then serve as a major fuel source.”

Known as ketosis, this metabolic state is characterized by extremely low insulin levels, as would occur during periods of fasting or starvation or while consuming a low-carb diet, such as the popular Atkins diet model.

For the past several years, Maratos-Flier’s laboratory has been studying the physiologic states of animals consuming various types of diets -- including standard “animal chow” diets and diets moderately high in both fats and carbohydrates, as well as ketogenic diets. And she has found through her experiments that even though mice are fed exactly the same number of calories, the composition of the calories causes them to gain weight in different ways.

“The differences in weight gain reflect differences in metabolic rates,” she explains. “These, in turn, result in hormonal changes that lead to different disposition of the calories.”

In this latest paper, Maratos-Flier and colleagues studied mice that had been fed a ketogenic diet high in both saturated fat and unsaturated fat and practically devoid of carbohydrates.

[...]


“Although the purpose of both of these studies was to glean insights into metabolic physiology, our findings suggest that increased levels of FGF21 may be a potential mechanism behind low-carbohydrate diets’ beneficial properties when it comes to lipid metabolism,” says Maratos-Flier. “Diets that limit carbohydrates and eliminate transfats, and at the same time emphasize fiber and good fats, appear to be healthiest, especially among individuals who are predisposed to developing diabetes.”

Diabetes Drug May Hold Potential As Treatment For Epilepsy, Using Same Mechanism As Ketogenic Diet

Diabetes Drug May Hold Potential As Treatment For Epilepsy, Using Same Mechanism As Ketogenic Diet

Two years ago, University of Wisconsin-Madison scientists reported they had suppressed epileptic seizures in rats by giving them a glycolytic-inhibitor, inhibiting the brain's ability to turn sugar into excess energy and blocking the expression of seizure-related genes. The discovery was greeted with excitement and hope for a new class of drugs for epilepsy, which afflicts more than 50 million people worldwide.

Now, in a presentation at Experimental Biology 2008 in San Diego,* Dr. Avtar Roopra describes a next step in this research that may mean a drug already widely used by people with diabetes could also be an effective and safe therapy for epilepsy, especially for that one third of patients who have recurrent seizures despite therapy with the best available antiepileptic drugs.

Although the earlier work by Dr. Roopra and his colleagues marked the first time a compound had been used for metabolic regulation of neuronal genes, epilepsy patients had been attempting to achieve the same goal - fewer seizures - for centuries through severe dietary restriction, in some cases with near starvation, more often with a high-fat, high-protein diet completely free of starches and sugars. Half of all drug-resistant people with epilepsy experience seizure control with this kind of severe ketogenic diet (although even a mild lapse can sometimes result in seizures).

The mechanism was completely unknown but the researchers reasoned it had to involve glycolysis, the recognition of sugar and its conversion to energy. And if that were correct, they asked, could they tap into this same biological pathway, bypassing dietary requirements altogether? The answer, published in Nature Neuroscience in October 2006, was 2-Deoxy-D-glucose, a compound that tricked the body into thinking it was sugar so that the cells stopped using the real thing as an energy source.

Now, in the new work, the researchers have identified a small molecule in the neurons that senses how much energy in available. Glucose turns on this sensor -- but so does Metformine, a FDA-approved prescription drug used by millions of people with diabetes to control their blood sugar. Dr. Roopra and his colleagues are now testing Metformine in the brains of mice to see how it affects the functioning of the hippocampus, the part of the brain involved with learning and memory and also the seat of seizures for many patients with epilepsy. The goal is to tamp down a mechanism called Long Term Potenciation enough to reduce the rate of epilepsy but not enough to affect the brain's ability to learn and remember.